Influence of vitamin D supplementation on bone mineral content, bone turnover markers, and fracture risk in South African schoolchildren: multicenter double-blind randomized placebo-controlled trial (ViDiKids)

Randomized controlled trials (RCTs) to determine the influence of vitamin D on BMC and fracture risk in children of Black African ancestry are lacking. We conducted a sub-study (n = 450) nested within a phase 3 RCT of weekly oral supplementation with 10 000 IU vitamin D3 vs placebo for 3 yr in HIV-uninfected Cape Town schoolchildren aged 6-11 yr. Outcomes were BMC at the whole body less head (WBLH) and LS and serum 25-hydroxyvitamin D3 (25(OH)D3), PTH, alkaline phosphatase, C-terminal telopeptide, and PINP. Incidence of fractures was a secondary outcome of the main trial (n = 1682). At baseline, mean serum 25(OH)D3 concentration was 70.0 nmol/L (SD 13.5), and 5.8% of participants had serum 25(OH)D3 concentrations <50 nmol/L. Among sub-study participants, end-trial serum 25(OH)D3 concentrations were higher for participants allocated to vitamin D vs placebo (adjusted mean difference [aMD] 39.9 nmol/L, 95% CI, 36.1 to 43.6) and serum PTH concentrations were lower (aMD -0.55 pmol/L, 95% CI, -0.94 to -0.17). However, no interarm differences were seen for WBLH BMC (aMD -8.0 g, 95% CI, -30.7 to 14.7) or LS BMC (aMD -0.3 g, 95% CI, -1.3 to 0.8) or serum concentrations of bone turnover markers. Fractures were rare among participants in the main trial randomized to vitamin D vs placebo (7/755 vs 10/758 attending at least 1 follow-up; adjusted odds ratio 0.70, 95% CI, 0.27 to 1.85). In conclusion, a 3-yr course of weekly oral vitamin D supplementation elevated serum 25(OH)D3 concentrations and suppressed serum PTH concentrations in HIV-uninfected South African schoolchildren of Black African ancestry but did not influence BMC or serum concentrations of bone turnover markers. Fracture incidence was low, limiting power to detect an effect of vitamin D on this outcome.

Comparative Study of Healthy Older and Younger Adults Shows They Have the Same Skin Concentration of Vitamin D3 Precursor, 7-Dehydrocholesterol, and Similar Response to UVR

Vitamin D3 synthesis in human skin is initiated by solar ultraviolet radiation (UVR) exposure of precursor 7-dehydrocholesterol (7DHC), but influence of age on the early stage of vitamin D3 metabolism is uncertain. We performed a prospective standardised study in healthy ambulant adults aged ≥65 and ≤40 years examining (1) if baseline skin 7DHC concentration differs between younger and older adults and (2) the impact of older age on serum vitamin D3 response to solar simulated UVR. Eleven younger (18-40 years) and 10 older (65-89 years) adults, phototype I-III, received low-dose UVR (95% UVA, 5% UVB, 1.3 SED) to ~35% of the body surface area. Biopsies were taken for 7DHC assay from unexposed skin, skin immediately and 24 h post-UVR, and blood sampled at baseline, 24 h and 7 d post-UVR for vitamin D3 assay. Samples were analysed by HPLC-MS/MS. Baseline skin 7DHC (mean ± SD) was 0.22 ± 0.07 and 0.25 ± 0.08 µg/mg in younger versus older adults (no significant difference). Baseline serum vitamin D3 concentration was 1.5 ± 1.5 and 1.5 ± 1.7 nmol/L in younger versus older adults, respectively, and showed a significant increase in both groups post-UVR (no significant differences between age groups). Thus, skin 7DHC concentration was not a limiting factor for vitamin D3 production in older relative to younger adults. This information assists public health guidance on sun exposure/vitamin D nutrition, with particular relevance to the growing populations of healthy ambulant adults ≥65 years.

Influence of vitamin D supplementation on growth, body composition, pubertal development and spirometry in South African schoolchildren: a randomised controlled trial (ViDiKids)

OBJECTIVE

To determine whether weekly oral vitamin D supplementation influences growth, body composition, pubertal development or spirometric outcomes in South African schoolchildren.

DESIGN

Phase 3 double-blind randomised placebo-controlled trial.

SETTING

Socioeconomically disadvantaged peri-urban district of Cape Town, South Africa.

PARTICIPANTS

1682 children of black African ancestry attending government primary schools and aged 6-11 years at baseline.

INTERVENTIONS

Oral vitamin D3 (10 000 IU/week) versus placebo for 3 years.

MAIN OUTCOME MEASURES

Height-for-age and body mass index-for-age, measured in all participants; Tanner scores for pubertal development, spirometric lung volumes and body composition, measured in a subset of 450 children who additionally took part in a nested substudy.

RESULTS

Mean serum 25-hydroxyvitamin D3 concentration at 3-year follow-up was higher among children randomised to receive vitamin D versus placebo (104.3 vs 64.7 nmol/L, respectively; mean difference (MD) 39.7 nmol/L, 95% CI 37.6 to 41.9 nmol/L). No statistically significant differences in height-for-age z-score (adjusted MD (aMD) -0.08, 95% CI -0.19 to 0.03) or body mass index-for-age z-score (aMD -0.04, 95% CI -0.16 to 0.07) were seen between vitamin D versus placebo groups at follow-up. Among substudy participants, allocation to vitamin D versus placebo did not influence pubertal development scores, % predicted forced expiratory volume in 1 s (FEV1), % predicted forced vital capacity (FVC), % predicted FEV1/FVC, fat mass or fat-free mass.

CONCLUSIONS

Weekly oral administration of 10 000 IU vitamin D3 boosted vitamin D status but did not influence growth, body composition, pubertal development or spirometric outcomes in South African schoolchildren.

TRIAL REGISTRATION NUMBERS

ClinicalTrials.gov NCT02880982, South African National Clinical Trials Register DOH-27-0916-5527.

Hormonal contraceptive use is associated with altered bone structural and metabolic responses to military training in women: An observational cohort study

Military training increases tibial density and size. Female sex hormones may influence the adaption of bone to loading, but it is unknown if women using different hormonal contraceptives adapt similarly to military training. One hundred and sixteen women (57 women not using hormonal contraceptives [non-users], 38 combined oral contraceptive pill [COCP] users, 21 depot medroxyprogesterone acetate [DMPA] users) completed this study. Tibial volumetric bone mineral density (vBMD) and geometry were measured by peripheral quantitative computed tomography (4 %, 14 %, 38 %, and 66 % sites) at the start (week 1) and end (week 14) of British Army basic training. Circulating markers of bone and calcium metabolism were measured at weeks 1, 2, 4, 6, 10, and 14. Training increased trabecular vBMD at the 4 % site, periosteal perimeter at the 14 % and 66 % sites, and total area, cortical area, cortical thickness, and bone strength at all sites (0.1 to 1.6 %, p ≤ 0.009), with no differences between hormonal contraceptive groups (p ≥ 0.127). Trabecular vBMD increased at the 14 % site in non-users (0.8 %, p = 0.005), but not in COCP or DMPA users (p ≥ 0.205). Periosteal perimeter increased at the 38 % site in COCP (0.4 %, p < 0.001) and DMPA (0.5 %, p < 0.001) users, but not in non-users (p = 0.058). Training had no effect on periosteal perimeter at the 4 % site or cortical vBMD or endosteal perimeter at any site (p ≥ 0.168). βCTX decreased and PINP increased during training with no difference between hormonal contraceptive groups. Training increased iPTH in non-users, but not COCP or DMPA users. Hormonal contraceptives may exert site-specific effects on the mechanobiology of bone, with higher endogenous oestradiol promoting trabecularisation and inhibiting periosteal expansion in non-users compared with hormonal contraceptive users.

Randomised trial of genetic testing and targeted intervention to prevent the development and progression of Paget's disease of bone

INTRODUCTION

Paget's disease of bone (PDB) frequently presents at an advanced stage with irreversible skeletal damage. Clinical outcomes might be improved by earlier diagnosis and prophylactic treatment.

METHODS

We randomised 222 individuals at increased risk of PDB because of pathogenic SQSTM1 variants to receive 5 mg zoledronic acid (ZA) or placebo. The primary outcome was new bone lesions assessed by radionuclide bone scan. Secondary outcomes included change in existing lesions, biochemical markers of bone turnover and skeletal events related to PDB.

RESULTS

The median duration of follow-up was 84 months (range 0-127) and 180 participants (81%) completed the study. At baseline, 9 (8.1%) of the ZA group had PDB lesions vs 12 (10.8%) of the placebo group. Two of the placebo group developed new lesions versus none in the ZA group (OR 0.41, 95% CI 0.00 to 3.43, p=0.25). Eight of the placebo group had a poor outcome (lesions which were new, unchanged or progressing) compared with none of the ZA group (OR 0.08, 95% CI 0.00 to 0.42, p=0.003). At the study end, 1 participant in the ZA group had lesions compared with 11 in the placebo group. Biochemical markers of bone turnover were significantly reduced in the ZA group. One participant allocated to placebo required rescue therapy with ZA because of symptomatic disease. The number and severity of adverse events did not differ between groups.

CONCLUSIONS

Genetic testing for pathogenic SQSTM1 variants coupled with intervention with ZA is well tolerated and has favourable effects on the progression of early PDB.

TRIAL REGISTRATION NUMBER

ISRCTN11616770.

Sex differences in iron status during military training: a prospective cohort study of longitudinal changes and associations with endurance performance and musculoskeletal outcomes

This study investigated sex differences in Fe status, and associations between Fe status and endurance and musculoskeletal outcomes, in military training. In total, 2277 British Army trainees (581 women) participated. Fe markers and endurance performance (2·4 km run) were measured at the start (week 1) and end (week 13) of training. Whole-body areal body mineral density (aBMD) and markers of bone metabolism were measured at week 1. Injuries during training were recorded. Training decreased Hb in men and women (mean change (-0·1 (95 % CI -0·2, -0·0) and -0·7 (95 % CI -0·9, -0·6) g/dl, both P < 0·001) but more so in women (P < 0·001). Ferritin decreased in men and women (-27 (95 % CI -28, -23) and -5 (95 % CI -8, -1) µg/l, both P ≤ 0·001) but more so in men (P < 0·001). Soluble transferrin receptor increased in men and women (2·9 (95 % CI 2·3, 3·6) and 3·8 (95 % CI 2·7, 4·9) nmol/l, both P < 0·001), with no difference between sexes (P = 0·872). Erythrocyte distribution width increased in men (0·3 (95 % CI 0·2, 0·4)%, P < 0·001) but not in women (0·1 (95 % CI -0·1, 0·2)%, P = 0·956). Mean corpuscular volume decreased in men (-1·5 (95 % CI -1·8, -1·1) fL, P < 0·001) but not in women (0·4 (95 % CI -0·4, 1·3) fL, P = 0·087). Lower ferritin was associated with slower 2·4 km run time (P = 0·018), sustaining a lower limb overuse injury (P = 0·048), lower aBMD (P = 0·021) and higher beta C-telopeptide cross-links of type 1 collagen and procollagen type 1 N-terminal propeptide (both P < 0·001) controlling for sex. Improving Fe stores before training may protect Hb in women and improve endurance and protect against injury.

Collagen peptide supplementation before bedtime reduces sleep fragmentation and improves cognitive function in physically active males with sleep complaints

PURPOSE

The primary aim of this study was to examine whether a glycine-rich collagen peptides (CP) supplement could enhance sleep quality in physically active men with self-reported sleep complaints.

METHODS

In a randomized, crossover design, 13 athletic males (age: 24 ± 4 years; training volume; 7 ± 3 h·wk1) with sleep complaints (Athens Insomnia Scale, 9 ± 2) consumed CP (15 g·day1) or a placebo control (CON) 1 h before bedtime for 7 nights. Sleep quality was measured with subjective sleep diaries and actigraphy for 7 nights; polysomnographic sleep and core temperature were recorded on night 7. Cognition, inflammation, and endocrine function were measured on night 7 and the following morning. Subjective sleepiness and fatigue were measured on all 7 nights. The intervention trials were separated by ≥ 7 days and preceded by a 7-night familiarisation trial.

RESULTS

Polysomnography showed less awakenings with CP than CON (21.3 ± 9.7 vs. 29.3 ± 13.8 counts, respectively; P = 0.028). The 7-day average for subjective awakenings were less with CP vs. CON (1.3 ± 1.5 vs. 1.9 ± 0.6 counts, respectively; P = 0.023). The proportion of correct responses on the baseline Stroop cognitive test were higher with CP than CON (1.00 ± 0.00 vs. 0.97 ± 0.05 AU, respectively; P = 0.009) the morning after night 7. There were no trial differences in core temperature, endocrine function, inflammation, subjective sleepiness, fatigue and sleep quality, or other measures of cognitive function or sleep (P > 0.05).

CONCLUSION

CP supplementation did not influence sleep quantity, latency, or efficiency, but reduced awakenings and improved cognitive function in physically active males with sleep complaints.

Perinatal morbidity among women with a previous caesarean delivery (PRISMA trial): a cluster-randomised trial

BACKGROUND

Women with a previous caesarean delivery face a difficult choice in their next pregnancy: planning another caesarean or attempting vaginal delivery, both of which are associated with potential maternal and perinatal complications. This trial aimed to assess whether a multifaceted intervention, which promoted person-centred decision making and best practices, would reduce the risk of major perinatal morbidity among women with one previous caesarean delivery.

METHODS

We conducted an open, multicentre, cluster-randomised, controlled trial of a multifaceted 2-year intervention in 40 hospitals in Quebec among women with one previous caesarean delivery, in which hospitals were the units of randomisation and women the units of analysis. Randomisation was stratified according to level of care, using blocked randomisation. Hospitals were randomly assigned (1:1) to the intervention group (implementation of best practices and provision of tools that aimed to support decision making about mode of delivery, including an estimation of the probability of vaginal delivery and an ultrasound estimation of the risk of uterine rupture), or the control group (no intervention). The primary outcome was a composite risk of major perinatal morbidity. This trial was registered with ISRCTN, ISRCTN15346559.

FINDINGS

21 281 eligible women delivered during the study period, from April 1, 2016 to Dec 13, 2019 (10 514 in the intervention group and 10 767 in the control group). None were lost to follow-up. There was a significant reduction in the rate of major perinatal morbidity from the baseline period to the intervention period in the intervention group as compared with the control group (adjusted odds ratio [OR] for incremental change over time, 0·72 [95% CI 0·52-0·99]; p=0·042; adjusted risk difference -1·2% [95% CI -2·0 to -0·1]). Major maternal morbidity was significantly reduced in the intervention group as compared with the control group (adjusted OR 0·54 [95% CI 0·33-0·89]; p=0·016). Minor perinatal and maternal morbidity, caesarean delivery, and uterine rupture rates did not differ significantly between groups.

INTERPRETATION

A multifaceted intervention supporting women in their choice of mode of delivery and promoting best practices resulted in a significant reduction in rates of major perinatal and maternal morbidity, without an increase in the rate of caesarean or uterine rupture.

FUNDING

Canadian Institutes of Health Research (CIHR, MOP-142448).

Prenatal paternal anxiety symptoms predict child DHEA levels and internalizing symptoms during adrenarche

Introduction

This study examined (1) whether measures of paternal anxious and depressive symptoms collected prenatally and during a follow-up assessment when the child was in middle childhood, predict child neuroendocrine outcomes, and (2) whether neuroendocrine outcomes are intermediate factors between paternal mental health and child cognitive/behavioral outcomes. Middle childhood coincides with increased autonomy as the child transitions into grade school, and with adrenarche, as the maturing adrenal gland increases secretion of dehydroepiandrosterone (DHEA) and its sulfated metabolite (DHEA-S), hormones that are implicated in corticolimbic development which regulate emotions and cognition.

Methods

Participants were recruited from a subsample of a large prospective birth cohort study (3D study). We conducted a follow-up study when children were 6-8 years old (N = 61 families, 36 boys, 25 girls). Parental symptoms of anxiety, stress and depression were assessed via validated self-report questionnaires: prenatally using an in-house anxiety questionnaire, the Perceived Stress Scale (PSS) and the Center for Epidemiologic Studies Depression (CES-D), and at the follow up, using the Beck Anxiety and Beck Depression Inventories. Children provided salivary hormone samples, and their pituitary gland volume was measured from structural Magnetic Resonance Imaging (MRI) scans. Child behaviors were measured using the Strengths and Difficulties Questionnaire and cognitive outcomes using the WISC-V. Multiple regression analyses were used to test whether paternal mental health symptoms assessed prenatally and during childhood are associated with child neuroendocrine outcomes, adjusting for maternal mental health and child sex. Indirect-effect models assessed whether neuroendocrine factors are important intermediates that link paternal mental health and cognitive/behavioral outcomes.

Results

(1) Fathers' prenatal anxiety symptoms predicted lower DHEA levels in the children, but not pituitary volume. (2) Higher prenatal paternal anxiety symptoms predicted higher child internalizing symptoms via an indirect pathway of lower child DHEA. No associations were detected between paternal anxiety symptoms measured in childhood, and neuroendocrine outcomes. No child sex differences were detected on any measure.

Conclusion

These results highlight the often-overlooked role of paternal factors during pregnancy on child development, suggesting that paternal prenatal anxiety symptoms are associated with child neuroendocrine function and in turn internalizing symptoms that manifest at least up to middle childhood.

Prenatal Exposure to Air Pollution and Respiratory Distress in Term Newborns: Results from the MIREC Prospective Pregnancy Cohort

BACKGROUND

Respiratory distress is the leading cause of neonatal morbidity and mortality worldwide, and prenatal exposure to air pollution is associated with adverse long-term respiratory outcomes; however, the impact of prenatal air pollution exposure on neonatal respiratory distress has not been well studied.

OBJECTIVES

We examined associations between prenatal exposures to fine particular matter (PM 2.5 ) and nitrogen dioxide (NO 2 ) with respiratory distress and related neonatal outcomes.

METHODS

We used data from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, a prospective pregnancy cohort (n = 2,001 ) recruited in the first trimester from 10 Canadian cities. Prenatal exposures to PM 2.5 (n = 1,321 ) and NO 2 (n = 1,064 ) were estimated using land-use regression and satellite-derived models coupled with ground-level monitoring and linked to participants based on residential location at birth. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for associations between air pollution and physician-diagnosed respiratory distress in term neonates in hierarchical logistic regression models adjusting for detailed maternal and infant covariates.

RESULTS

Approximately 7 % of newborns experienced respiratory distress. Neonates received clinical interventions including oxygen therapy (6%), assisted ventilation (2%), and systemic antibiotics (3%). Two percent received multiple interventions and 4% were admitted to the neonatal intensive care unit (NICU). Median PM 2.5 and NO 2 concentrations during pregnancy were 8.81   μ g / m 3 and 18.02  ppb , respectively. Prenatal exposures to air pollution were not associated with physician-diagnosed respiratory distress, oxygen therapy, or NICU admissions. However, PM 2.5 exposures were strongly associated with assisted ventilation (OR per 1 - μ g / m 3 increase in PM 2.5 = 1.17 ; 95% CI: 1.02, 1.35), multiple clinical interventions (OR per 1 - μ g / m 3 increase in PM 2.5 = 1.16 ; 95% CI: 1.07, 1.26), and systemic antibiotics, (OR per 1 - μ g / m 3 increase in PM 2.5 = 1.12 ; 95% CI: 1.04, 1.21). These associations were consistent across exposure periods-that is, during prepregnancy, individual trimesters, and total pregnancy-and robust to model specification. NO 2 exposure was associated with administration of systemic antibiotics (OR per 1-ppb increase in NO 2 = 1.03 ; 95% CI: 1.00, 1.06).

DISCUSSION

Prenatal exposures to PM 2.5 increased the risk of severe respiratory distress among term newborns. These findings support the development and prioritization of public health and prenatal care strategies to increase awareness and minimize prenatal exposures to air pollution. https://doi.org/10.1289/EHP12880.

Cross-sectional study of the associations between circulating vitamin D concentrations and insulin resistance in children aged 9-10 years of South Asian, black African Caribbean and white European origins

BACKGROUND

Lower circulating vitamin D 25-hydroxyvitamin D (25(OH)D) concentrations are associated with higher type 2 diabetes risk in adults, although causality remains uncertain. However, associations between 25(OH)D and type 2 diabetes risk markers in children have been little studied, particularly in ethnic minority populations. We examined whether 25(OH)D concentrations were associated with insulin resistance in children and whether lower 25(OH)D concentrations in South Asians and black African Caribbeans could contribute to their higher insulin resistance.

METHODS

Cross-sectional study of 4650 UK primary school children aged 9-10 years of predominantly South Asian, black African Caribbean and white European ethnicity. Children had fasting blood measurements of circulating 25(OH)D metabolite concentrations, insulin and glucose.

RESULTS

Lower 25(OH)D concentrations were observed in girls, South Asians and black African Caribbeans. In analyses adjusted for age, sex, month, ethnic group and school, circulating 25(OH)D was inversely associated with fasting insulin (-0.38%, 95% CI -0.49% to -0.27%), homoeostasis model assessment (HOMA) insulin resistance (-0.39%, 95% CI -0.50% to -0.28%) and fasting glucose (-0.03%, 95% CI -0.05% to -0.02%) per nmol/L increase in 25(OH)D; associations did not differ between ethnic groups. Ethnic differences in fasting insulin and HOMA insulin resistance (higher among South Asian and black African Caribbeans) were reduced by >40% after adjustment for circulating 25(OH)D concentrations.

CONCLUSION

Circulating vitamin D was inversely associated with insulin resistance in all ethnic groups; higher insulin resistance in South Asian and black African children were partly explained by their lower vitamin D levels. Whether vitamin D supplementation can reduce emerging type 2 diabetes risk needs further evaluation.

Childhood exposure to pyrethroids and neurodevelopment in Canadian preschoolers

BACKGROUND

Pyrethroid insecticides are used both residentially and agriculturally and their toxicity targets the nervous system of insects. They might also interfere with development and function of the human brain. A few epidemiological studies suggest that exposure to pyrethroids may be associated with neurobehavioral problems in children but there is little data on potential associations with cognitive outcomes. Furthermore, many studies showed that the neurotoxic effects of several pesticides are modified by sex, hence, considerations of potential sex-differences are important to investigate.

OBJECTIVE

To study the cross-sectional association between urinary levels of pyrethroid metabolites and neurodevelopment, including neurobehavioral and cognitive outcomes, in preschool-age children, and to examine whether sex might modify these associations.

METHODS

We used data from a follow-up examination of the Maternal-Infant Research on Environmental Chemicals (MIREC), the MIREC Child Development study (MIREC-CD Plus) on children at age 3-4 years living in 6 Canadian cities. For each participant, we collected a urine sample for measurements of pyrethroids metabolites (cis-DBCA, cis-DCCA, trans-DCCA, 3-PBA, 4-F-3-PBA). We assessed neurodevelopment with the Wechsler Primary and Preschool Scale of Intelligence-III (WPPSI-III) and two scales of the Behavior Rating Inventory of Executive Function-Preschool (BRIEF-P). Parents reported children's behavior using the Behavior Assessment System for Children-2 (BASC-2) and the Social Responsiveness Scale-2 (SRS-2). We examined associations between children's urinary pyrethroid metabolite concentrations and neurodevelopmental scores with multiple linear regression models, adjusting for confounders, in boys and girls separately.

RESULTS

The study included 179 children (mean age: 3.2 y, range 2.8-4.0). The detection frequencies were high for most pyrethroid metabolites (83-100%), but lower for 4-F-3-PBA (36%). Higher concentrations of cis-DBCA were significantly associated with lower verbal, performance and full-scale IQ scores in boys (e.g., for a 2-fold increase in cis-DBCA, β = -2.0; 95% CI: -3.4, -0.6 for full-scale IQ). In girls, the only metabolite associated with cognitive scores was 3-PBA, which was associated with lower verbal IQ scores (β = -1.3, 95% CI: -2.6, -0.1). For neurobehavioral outcomes in boys, there were associations between poorer BASC-2 Adaptive Skills scores with higher concentrations of cis-DCCA (β = -1.6, 95% CI: -2.3, -0.9), trans-DCCA (β = -1.5, 95% CI: -2.2, -0.8), 3-PBA (β = -1.7, 95% CI: -2.5, -0.9), and sum of pyrethroid metabolites (β = -1.8, 95% CI: -2.6, -0.9). In girls, we observed a significant association between higher concentration of cis-DCCA and better BASC-2 Adaptive Skills score (β = 1.0; 95% CI, 0.2, 1.8), but not with other urinary pyrethroids metabolites. Scores on the SRS-2 and BRIEF-P were not associated with pyrethroid metabolites.

CONCLUSION

There were associations between some pyrethroid pesticide metabolites and indicators of neurodevelopmental disorder, especially among boys. These associations are in agreement with previous studies and could suggest that exposure to pyrethroid pesticides represents a risk of potential toxicity for the cognitive development of children, and a risk for behavioral development. However, the cross-sectional nature of this study limits causal inferences.

The collagen synthesis response to an acute bout of resistance exercise is greater when ingesting 30 g versus 15 g and 0 g hydrolyzed collagen in resistance-trained young men

BACKGROUND

Resistance exercise (RE) stimulates collagen synthesis in skeletal muscle and tendon but there is limited and equivocal evidence regarding an effect of collagen supplementation and exercise on collagen synthesis. Furthermore, it is not known if a dose-response exists regarding the effect of hydrolyzed collagen (HC) ingestion and RE on collagen synthesis.

OBJECTIVE

We aimed to determine the HC dose-response effect on collagen synthesis following high-intensity RE in resistance-trained young men.

METHODS

Using a double-blind, randomized cross-over design, 10 resistance-trained men (age: 26±3 years; height: 1.77±0.04 m; mass: 79.7±7.0 kg) ingested 0g, 15g or 30g HC with 50mg vitamin C 1h prior to performing four sets' barbell back-squat RE at 10-repetition maximum load, after which they rested for six hours. Blood samples were collected throughout each of the three interventions to analyse procollagen type Ⅰ N-terminal propeptide (PⅠNP) and β-isomerized C-terminal telopeptide of type I collagen (β-CTX) concentration, and the concentration of 18 collagen amino acids.

RESULTS

The serum PⅠNP concentration×time area-under-the-curve (AUC) was greater for 30g (267±79 μg∙L-1∙h) than 15g (235±70 μg∙L-1∙h, P=0.039) and 0g HC (219±88 μg∙L-1∙h, P=0.005) but there was no difference between 0g and 15g HC (P=0.675). The AUCs of glycine and proline were greater for 30g than for 15g and 0g HC (P<0.05). Plasma β-CTX concentration decreased from -1h to +6h (P<0.05), with no differences between interventions.

CONCLUSION

The greater PINP AUC suggests 30g HC ingested prior to high-intensity RE augments whole body collagen synthesis more than 15g and 0g HC in resistance-trained young men.

Antidepressants use during pregnancy and child psychomotor, cognitive and language development at 2 years of age-Results from the 3D Cohort Study

Introduction: Approximately 5.5% of pregnant women take antidepressants. Studies on prenatal exposure to antidepressants reported no association with child cognition, and inconsistent results with motor function and language development. A limitation has been the failure to adjust for prenatal maternal distress. Objectives: Assess the associations between prenatal exposure to antidepressants and child development at age two, while adjusting for maternal depressive symptoms and stress during pregnancy. Explore indirect effects through birth complications and consider sex-specific associations. Methods: This is an ancillary study of the 3D (Design Develop, Discover) Study initiated during pregnancy. Data on antidepressants were collected through medication logs spanning the entire pregnancy. Depressive symptoms and stress were assessed during pregnancy by self-reported questionnaires, motor and cognitive development with the Bayley Scales of Infant and Toddler Development (BSID-III), and language development with the MacArthur Communicative Development Inventories at age 2. Multiple linear regressions were used to assess the associations between exposure and developmental outcomes. Mediation models were used to assess indirect effects. Interaction terms were introduced to assess sex-specific associations. Results: 1,489 mother-child dyads were included, of whom 61 (4.1%) reported prenatal antidepressant use. Prenatal exposure was negatively associated with motor development (B = -0.91, 95% CI -1.73, -0.09 for fine motor, B = -0.89, 95% CI -1.81, 0.02 for gross motor), but not with cognitive (B = -0.53, 95% CI -1.82, 0.72) and language (B = 4.13, 95% CI -3.72, 11.89) development. Adjusting for maternal prenatal distress only slightly modified these associations. No indirect effect or differential effect according to child sex were found. Conclusion: This study supports evidence of a negative association between prenatal exposure to antidepressants and motor development at age two, after adjusting for maternal distress, but the effect size remains very small, with about only one BSID-III point lower in average.

Second-trimester abortion and risk of live birth

BACKGROUND

Second-trimester abortion may result in a live birth, but the extent to which this outcome occurs is unknown.

OBJECTIVE

This study aimed to examine rates of live birth after pregnancy termination in the second trimester and identify associated risk factors.

STUDY DESIGN

We conducted a retrospective cohort study of 13,777 second-trimester abortions occurring in hospital settings between April 1, 1989 and March 31, 2021 in Quebec, Canada. The exposure was induced abortion between 15 and 29 weeks of gestation, including the indication for (fetal anomaly, maternal emergency, other) and use of feticidal injection (intracardiac/intrathoracic or intraamniotic). The primary outcome was live birth following abortion. We measured the rate of live birth per 100 abortions and used adjusted log-binomial regression models to estimate risk ratios and 95% confidence intervals for the association of fetal and maternal characteristics with the risk of live birth. We assessed the extent to which feticidal injection reduced the risk.

RESULTS

Among 13,777 abortions between 15 and 29 weeks of gestation, 1541 (11.2%) led to live birth. Fetal anomaly was a common indication for termination (48.1%), and most abortions were by labor induction (72.2%). Compared with abortion between 15 and 19 weeks, abortion between 20 and 24 weeks was associated with 4.80 times the risk of live birth (95% confidence interval, 4.20-5.48), whereas abortion between 25 and 29 weeks was associated with 1.34 times the risk (95% confidence interval, 1.00-1.79). Feticidal injection reduced the risk of live birth by 57% compared with no injection (risk ratio, 0.43; 95% confidence interval, 0.36-0.51). Intracardiac or intrathoracic injection was particularly effective at preventing live birth (risk ratio, 0.02; 95% confidence interval, 0.01-0.07).

CONCLUSION

Second-trimester abortion carries a risk of live birth, especially at 20 to 24 weeks of gestation, although feticidal injection may protect against this outcome.

Longitudinal associations between paternal mental health and child behavior and cognition in middle childhood

Introduction

Paternal mental health has been associated with adverse consequences on offspring psychosocial development, and family environmental factors may partly explain those associations. To clarify this, we need comprehensive prospective studies, particularly in middle-childhood when the child enters school and is expected to make use of behavioral and cognitive skills as part of their interactions and learning.

Method

Using data from a sub-sample of the prospective 3D birth cohort study comprised of mother-father-child triads, and a follow-up of the parents and the children at 6-8 years of age (n = 61; 36 boys, 25 girls), we examined whether paternal anxious and depressive symptoms measured during the pregnancy period (i.e., prenatally) or concurrently when the child was assessed at 6-8 years old were associated with children's cognition/behavior.

Results

In contrast to our hypotheses, we found that greater prenatal paternal depressive symptoms predicted fewer child behavioral difficulties; and that greater concurrent childhood paternal depression or anxiety symptoms were associated with higher child full-scale IQ, controlling for the equivalent maternal mental health assessment and parental education. Father parenting perception did not mediate these associations, nor were they moderated by maternal mental health at the concurrent assessment, or paternal ratings of marital relationship quality.

Discussion

These findings suggest that higher symptoms of paternal mental health symptoms are associated with fewer child behavioral difficulties and higher cognitive performance in middle childhood. Potential clinical implications and future research directions are discussed.

Cohort profile update: The Canadian Maternal-Infant Research on Environmental Chemicals Child Development study (MIREC-CD PLUS)

BACKGROUND

The pan-Canadian Maternal-Infant Research on Environmental Chemicals (MIREC) study was established to determine whether maternal environmental chemical exposures were associated with adverse pregnancy outcomes in 2001 pregnant women.

OBJECTIVES

The MIREC-Child Development (CD PLUS) study followed this cohort with the goal of assessing the potential effects of prenatal exposures on anthropometry and neurodevelopment in early childhood.

POPULATION

MIREC families with children between the ages of 15 months and 5 years who had agreed to be contacted for future research (n = 1459) were invited to participate in MIREC-CD PLUS which combines data collected from an online Maternal Self-Administered Questionnaire with biomonitoring and neurodevelopment data collected from two in-person visits.

PRELIMINARY RESULTS

Between April 2013 and March 2015, 803 children participated in the Biomonitoring visit where we collected anthropometric measures, blood, and urine from the children. The Behavioural Assessment System for Children-2, Behaviour Rating Inventory of Executive Function, MacArthur-Bates Communicative Development Inventories and the Communication subscale of the Adaptive Behaviour Scale from the Bayley Scales of Infant and Toddler Development-III are available on close to 900 children. There were 610 singleton children who completed in-person visits for neurodevelopment assessments including the Social Responsiveness Scale, Wechsler Preschool Primary Scale of Intelligence-III and NEuroPSYchological assessments (NEPSY). Currently, we are following the cohort into early adolescence to measure the impact of early life exposures on endocrine and metabolic function (MIREC-ENDO).

CONCLUSIONS

Data collection for the MIREC-CD PLUS study is complete and analysis of the data continues. We are now extending the follow-up of the cohort into adolescence to measure the impact of early life exposures on endocrine and metabolic function (MIREC-ENDO). MIREC-CD PLUS is limited by loss to follow-up and the fact that mothers are predominately of higher socioeconomic status and 'White' ethnicity, which limits our generalizability. However, the depth of biomonitoring and clinical measures in MIREC provides a platform to examine associations of prenatal, infancy and childhood exposures with child growth and development.

Vitamin D Metabolites Are Associated With Musculoskeletal Injury in Young Adults: A Prospective Cohort Study

The relationship between vitamin D metabolites and lower body (pelvis and lower limb) overuse injury is unclear. In a prospective cohort study, we investigated the association between vitamin D metabolites and incidence of lower body overuse musculoskeletal and bone stress injury in young adults undergoing initial military training during all seasons. In 1637 men and 530 women (aged 22.6 ± 7.5 years; body mass index [BMI], 24.0 ± 2.6 kg/m- 2 ; 94.3% white ethnicity), we measured serum 25-hydroxyvitamin D (25(OH)D) and 24,25-dihydroxyvitamin D (24,25(OH)2 D) by high-performance liquid chromatography tandem mass spectrometry, and 1,25-dihydroxyvitamin D (1,25(OH)2 D) by immunoassay during week 1 of training. We examined whether the relationship between 25(OH)D and 1,25(OH)2 D:24,25(OH)2 D ratio was associated with overuse injury. During 12 weeks of training, 21.0% sustained ≥1 overuse musculoskeletal injury, and 5.6% sustained ≥1 bone stress injury. After controlling for sex, BMI, 2.4 km run time, smoking, bone injury history, and Army training course (Officer, standard, or Infantry), lower body overuse musculoskeletal injury incidence was higher for participants within the second lowest versus highest quartile of 24,25(OH)2 D (odds ratio [OR] = 1.62; 95% confidence interval [CI] 1.13-2.32; p = 0.009) and lowest versus highest cluster of 25(OH)D and 1,25(OH)2 D:24,25(OH)2 D (OR = 6.30; 95% CI 1.89-21.2; p = 0.003). Lower body bone stress injury incidence was higher for participants within the lowest versus highest quartile of 24,25(OH)2 D (OR = 4.02; 95% CI 1.82-8.87; p < 0.001) and lowest versus highest cluster of 25(OH)D and 1,25(OH)2 D:24,25(OH)2 D (OR = 22.08; 95% CI 3.26-149.4; p = 0.001), after controlling for the same covariates. Greater conversion of 25(OH)D to 24,25(OH)2 D, relative to 1,25(OH)2 D (ie, low 1,25(OH)2 D:24,25(OH)2 D), and higher serum 24,25(OH)2 D were associated with a lower incidence of lower body overuse musculoskeletal and bone stress injury. Serum 24,25(OH)2 D may have a role in preventing overuse injury in young adults undertaking arduous physical training. © 2023 Crown copyright and The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR). This article is published with the permission of the Controller of HMSO and the King's Printer for Scotland.

Vitamin D supplementation to prevent tuberculosis infection in South African schoolchildren: multicenter phase 3 double-blind randomized placebo-controlled trial (ViDiKids)

OBJECTIVES

To determine whether weekly oral supplementation with 10,000 IU vitamin D3 for 3 years reduces the risk of sensitization to M. tuberculosis in South African schoolchildren aged 6-11 years with negative QuantiFERON-tuberculosis (TB) Gold Plus (QFT-Plus) assay results at baseline.

METHODS

We conducted a phase 3 randomized placebo-controlled trial in 1682 children attending 23 primary schools in Cape Town. The primary outcome was a positive end-trial QFT-Plus result, analyzed using a mixed effects logistic regression model with the school of attendance included as a random effect.

RESULTS

829 vs. 853 QFT-Plus-negative children were randomized to receive vitamin D3 vs. placebo, respectively. Mean end-study 25(OH)D concentrations in participants randomized to vitamin D vs. placebo were 104.3 vs 64.7 nmol/l, respectively (95% confidence interval for difference, 37.6 to 41.9 nmol/l). A total of 76/667 (11.4%) participants allocated to vitamin D vs. 89/687 (13.0%) participants allocated to placebo tested QFT-Plus positive at 3-year follow-up (adjusted odds ratio 0.86, 95% confidence interval 0.62-1.19, P = 0.35).

CONCLUSION

Weekly oral supplementation with 10,000 IU vitamin D3 for 3 years elevated serum 25(OH)D concentrations among QFT-Plus-negative Cape Town schoolchildren but did not reduce their risk of QFT-Plus conversion.

The additive effect of vitamin K supplementation and bisphosphonate on fracture risk in post-menopausal osteoporosis: a randomised placebo controlled trial

This study assessed whether vitamin K, given with oral bisphosphonate, calcium and/or vitamin D has an additive effect on fracture risk in post-menopausal women with osteoporosis. No difference in bone density or bone turnover was observed although vitamin K1 supplementation led to a modest effect on parameters of hip geometry.

PURPOSE

Some clinical studies have suggested that vitamin K prevents bone loss and may improve fracture risk. The aim was to assess whether vitamin K supplementation has an additive effect on bone mineral density (BMD), hip geometry and bone turnover markers (BTMs) in post-menopausal women with osteoporosis (PMO) and sub-optimum vitamin K status receiving bisphosphonate, calcium and/or vitamin D treatment.

METHODS

We conducted a trial in 105 women aged 68.7[12.3] years with PMO and serum vitamin K1 ≤ 0.4 µg/L. They were randomised to 3 treatment arms; vitamin K1 (1 mg/day) arm, vitamin K2 arm (MK-4; 45 mg/day) or placebo for 18 months. They were on oral bisphosphonate and calcium and/or vitamin D. We measured BMD by DXA, hip geometry parameters using hip structural analysis (HSA) software and BTMs. Vitamin K1 or MK-4 supplementation was each compared to placebo. Intention to treat (ITT) and per protocol (PP) analyses were performed.

RESULTS

Changes in BMD at the total hip, femoral neck and lumbar spine and BTMs; CTX and P1NP did not differ significantly following either K1 or MK-4 supplementation compared to placebo. Following PP analysis and correction for covariates, there were significant differences in some of the HSA parameters at the intertrochanter (IT) and femoral shaft (FS): IT endocortical diameter (ED) (% change placebo:1.5 [4.1], K1 arm: -1.02 [5.07], p = 0.04), FS subperiosteal/outer diameter (OD) (placebo: 1.78 [5.3], K1 arm: 0.46 [2.23] p = 0.04), FS cross sectional area (CSA) (placebo:1.47 [4.09],K1 arm: -1.02[5.07], p = 0.03).

CONCLUSION

The addition of vitamin K1 to oral bisphosphonate with calcium and/or vitamin D treatment in PMO has a modest effect on parameters of hip geometry. Further confirmatory studies are needed.

TRIAL REGISTRATION

The study was registered at Clinicaltrial.gov:NCT01232647.

The effect of calcium supplementation on calcium and bone metabolism during load carriage in women: protocol for a randomised controlled crossover trial

BACKGROUND

Military field exercises are characterised by high volumes of exercise and prolonged periods of load carriage. Exercise can decrease circulating serum calcium and increase parathyroid hormone and bone resorption. These disturbances to calcium and bone metabolism can be attenuated with calcium supplementation immediately before exercise. This randomised crossover trial will investigate the effect of calcium supplementation on calcium and bone metabolism, and bone mineral balance, during load carriage exercise in women.

METHODS

Thirty women (eumenorrheic or using the combined oral contraceptive pill, intrauterine system, or intrauterine device) will complete two experimental testing sessions either with, or without, a calcium supplement (1000 mg). Each experimental testing session will involve one 120 min session of load carriage exercise carrying 20 kg. Venous blood samples will be taken and analysed for biochemical markers of bone resorption and formation, calcium metabolism, and endocrine function. Urine will be collected pre- and post-load carriage to measure calcium isotopes for the calculation of bone calcium balance.

DISCUSSION

The results from this study will help identify whether supplementing women with calcium during load carriage is protective of bone and calcium homeostasis.

TRIAL REGISTRATION

NCT04823156 (clinicaltrials.gov).

Capturing sex-specific and hypofertility-linked effects of assisted reproductive technologies on the cord blood DNA methylome

BACKGROUND

Children conceived through assisted reproduction are at an increased risk for growth and genomic imprinting disorders, often linked to DNA methylation defects. It has been suggested that assisted reproductive technology (ART) and underlying parental infertility can induce epigenetic instability, specifically interfering with DNA methylation reprogramming events during germ cell and preimplantation development. To date, human studies exploring the association between ART and DNA methylation defects have reported inconsistent or inconclusive results, likely due to population heterogeneity and the use of technologies with limited coverage of the epigenome. In our study, we explored the epigenetic risk of ART by comprehensively profiling the DNA methylome of 73 human cord blood samples of singleton pregnancies (n = 36 control group, n = 37 ART/hypofertile group) from a human prospective longitudinal birth cohort, the 3D (Design, Develop, Discover) Study, using a high-resolution sequencing-based custom capture panel that examines over 2.4 million autosomal CpGs in the genome.

RESULTS

We identified evidence of sex-specific effects of ART/hypofertility on cord blood DNA methylation patterns. Our genome-wide analyses identified ~ 46% more CpGs affected by ART/hypofertility in female than in male infant cord blood. We performed a detailed analysis of three imprinted genes which have been associated with altered DNA methylation following ART (KCNQ1OT1, H19/IGF2 and GNAS) and found that female infant cord blood was associated with DNA hypomethylation. When compared to less invasive procedures such as intrauterine insemination, more invasive ARTs (in vitro fertilization, intracytoplasmic sperm injection, embryo culture) resulted in more marked and distinct effects on the cord blood DNA methylome. In the in vitro group, we found a close to fourfold higher proportion of significantly enriched Gene Ontology terms involved in development than in the in vivo group.

CONCLUSIONS

Our study highlights the ability of a sensitive, targeted, sequencing-based approach to uncover DNA methylation perturbations in cord blood associated with hypofertility and ART and influenced by offspring sex and ART technique invasiveness.

Small-for-gestational-age and predictors of HOMA indices, leptin and adiponectin in infancy

AIM

To assess whether small-for-gestational-age (SGA) - an indicator of poor fetal growth, may affect metabolic health biomarkers in infancy and explore the predictors.

METHODS

This was a nested matched (1:2) prospective observational study of 65 SGA (birth weight <10^th percentile) and 130 optimal-for-gestational-age (OGA, birth weight 25^th -75^th percentiles, control) infants in the 3D birth cohort with subjects recruited in Canada from 1 May 2010 to 31 August 2012. The outcomes included homeostasis model assessment of insulin resistance (HOMA-IR) and beta-cell function (HOMA-β), circulating leptin and adiponectin concentrations at age 2 years.

RESULTS

HOMA-IR, HOMA-β, leptin and adiponectin concentrations were similar in SGA vs. OGA infants. Female sex and accelerated growth in length during mid-infancy (3-12 months) were associated with higher HOMA-IR. Caucasian ethnicity and decelerated growth in weight during late infancy (12-24 months) were associated with lower HOMA-IR. Current BMI was positively associated with circulating adiponectin in SGA infants only [+13.4% (4.0-23.7%) per BMI z score increment].

CONCLUSION

Insulin resistance and secretion, circulating leptin and adiponectin levels were normal in SGA subjects in infancy at age 2 years. The novel observation in SGA-specific positive association between current BMI and circulating adiponectin suggests dysfunctional adiposity-adiponectin negative feedback loop development during infancy in SGA subjects.

The effect of sex and protein supplementation on bone metabolism during a 36-hour military field exercise in energy deficit

This study investigated sex differences in, and the effect of protein supplementation on, bone metabolism during a 36-hour military field exercise. Forty-four British Army Officer cadets (14 women) completed a 36-hour field exercise. Participants consumed their habitual diet (n = 14 women [Women] and n = 15 men [Men Controls]) or the habitual diet and an additional 46.6 g·d^-1 protein in men (n = 15 men [Men Protein]). Women and Men Protein were compared with Men Controls to examine the effect of sex and protein supplementation. Circulating markers of bone metabolism were measured before, 24 hours after (post-exercise), and 96 hours after (recovery) the field exercise. βCTX and cortisol were not different between timepoints or Women and Men Controls (p ≥ 0.094). PINP decreased from baseline to post-exercise (p < 0.001) and recovery (p < 0.001) in Women and Men Controls. PTH increased from baseline to post-exercise (p = 0.006) and decreased from post-exercise to recovery (p = 0.047) in Women and Men Controls. Total 25(OH)D increased from baseline to post-exercise (p = 0.038) and recovery (p < 0.001) in Women and Men Controls. Testosterone decreased from baseline to post-exercise (p < 0.001) and recovery (p = 0.007) in Men Controls, but did not change for Women (all p = 1.000). Protein supplementation in men had no effect on any marker. Men and women experience similar changes to bone metabolism-decreased bone formation and increased PTH-following a short field exercise. Protein had no protective effect likely because of the energy deficit.

Early renal impairment affects hormonal regulators of calcium and bone metabolism and Wnt signalling and the response to vitamin D supplementation in healthy older adults

Bone and renal metabolism are regulated by common factors and there is extensive cross-talk between these organs (the 'renal-bone-axis'). Ageing is associated with physiological changes including reduced bone mass, renal function and tissue sensitivity to regulatory hormones, impacting the renal-bone axis. We aimed to investigate the influence of estimated Glomerular Filtration Rate (eGFR) on plasma concentrations of vitamin D metabolites, Wnt signalling and bone metabolism in a dose ranging vitamin D₃ RCT (12,000 IU, 24,000 IU, 48,000 IU/month for 1 year; n = 379, >70 y) with a baseline eGFR > 30 mL/min/1.73 m². Participants were categorised on basis of eGFR (≥60 or mL/min/1.73 m²) based on 5 commonly used algorithms for eGFR. Differences between eGFR categories were tested with ANCOVA. Before supplementation commenced, a lower eGFR was associated with significantly higher concentrations of c-terminal and intact Fibroblast Growth Factor-23 (cFGF23; iFGF23), intact Parathyroid Hormone (iPTH) and Sclerostin (SOST) and lower Klotho, 1,25-dihydroxy Vitamin D (1,25(OH)₂D) and Dickkopf-related Protein 1 (DKK1) concentrations. Differences between eGFR groups in 25-hydroxy Vitamin D (25(OH)D), 24,25-dihydroxy Vitamin D (24,25(OH)₂D) and iPTH were only detected with eGFR based on Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Modification in Diet for Renal Disease (MDRD-4) algorithms. Differences in Bone Mineral Density and Content (BMD; BMC) and bone turnover markers were detected only with Cockcroft-Gault (CG). Pre- and post- supplementation comparisons showed differences in the response to supplementation by eGFR group. Plasma 25(OH)D, 24,25(OH)₂D, 1,25(OH)₂D and DKK1 increased and iPTH and C-terminal telopeptide (CTX) decreased in both groups. Plasma iFGF23, bone specific alkaline phosphatase (BAP) and Procollagen 1 intact N-terminal Propeptide (PINP) increased and phosphate decreased only in the group with eGFR ≥ 60 mL/min/1.73 m². Findings were largely consistent across all eGFR algorithms. Post-supplementation, cFGF23, iFGF23, iPTH and SOST remained significantly higher in the lower eGFR group. Plasma 1,25(OH)₂D and Klotho did no longer differ between eGFR groups. This was found for all eGFR algorithms, with the exception of iPTH and iFGF23, which were not significantly different with eGFR based on CG. Differences in BMD and BMC were detected with CKD-EPI-creatinine and MDRD-4 but not GC. This study showed that even a moderate decline in eGFR is associated with alterations in vitamin D metabolism, Wnt signalling and bone turnover markers. Renal function influenced the response to vitamin D supplementation. Supplementation increased Vitamin D metabolites in the group with moderate renal impairment to concentrations comparable to those found in the group with normal renal function. However, although CTX decreased, an increase in bone formation markers was not found in the group with eGFR 60 mL/min/1.73 m². In conclusion, vitamin D supplementation had beneficial effects on markers of the renal-bone axis in older people with both normal and impaired renal function.

Individual, Independent, and Joint Associations of Toxic Metals and Manganese on Hypertensive Disorders of Pregnancy: Results from the MIREC Canadian Pregnancy Cohort

BACKGROUND

Toxic metals, such as lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg), may be associated with a higher risk of gestational hypertension and preeclampsia, whereas manganese (Mn) is an essential metal that may be protective.

OBJECTIVES

We estimated the individual, independent, and joint associations of Pb, Cd, As, Hg, and Mn on the risk of developing gestational hypertension and preeclampsia in a cohort of Canadian women.

METHODS

Metal concentrations were analyzed in first and third trimester maternal blood (n=1,560). We measured blood pressure after 20 wk gestation to diagnose gestational hypertension, whereas proteinuria and other complications defined preeclampsia. We estimated individual and independent (adjusted for coexposure) relative risks (RRs) for each doubling of metal concentrations and examined interactions between toxic metals and Mn. We used quantile g-computation to estimate the joint effect of trimester-specific exposures.

RESULTS

Each doubling of third trimester Pb (RR=1.54; 95% CI: 1.06, 2.22) and first trimester blood As (RR=1.25; 95% CI: 1.01, 1.58) was independently associated with a higher risk of developing preeclampsia. First trimester blood As (RR=3.40; 95% CI: 1.40, 8.28) and Mn (RR=0.63; 95% CI: 0.42, 0.94) concentrations were associated with a higher and lower risk, respectively, of developing gestational hypertension. Mn modified the association with As such that the deleterious association with As was stronger at lower concentrations of Mn. First trimester urinary dimethylarsinic acid concentrations were not associated with gestational hypertension (RR=1.31; 95% CI: 0.60, 2.85) or preeclampsia (RR=0.92; 95% CI: 0.68, 1.24). We did not observe overall joint effects for blood metals.

DISCUSSION

Our results confirm that even low blood Pb concentrations are a risk factor for preeclampsia. Women with higher blood As concentrations combined with lower Mn in early pregnancy were more likely to develop gestational hypertension. These pregnancy complications impact maternal and neonatal health. Understanding the contribution of toxic metals and Mn is of public health importance. https://doi.org/10.1289/EHP10825.

YBX1-interacting small RNAs and RUNX2 can be blocked in primary bone cancer using CADD522

Primary bone cancer (PBC) comprises several subtypes each underpinned by distinctive genetic drivers. This driver diversity produces novel morphological features and clinical behaviour that serendipitously makes PBC an excellent metastasis model. Here, we report that some transfer RNA-derived small RNAs termed tRNA fragments (tRFs) perform as a constitutive tumour suppressor mechanism by blunting a potential pro-metastatic protein-RNA interaction. This mechanism is reduced in PBC progression with a gradual loss of tRNAGly^TCC cleavage into 5' end tRF-Gly^TCC when comparing low-grade, intermediate-grade and high-grade patient tumours. We detected recurrent activation of miR-140 leading to upregulated RUNX2 expression in high-grade patient tumours. Both tRF-Gly^TCC and RUNX2 share a sequence motif in their 3' ends that matches the YBX1 recognition site known to stabilise pro-metastatic mRNAs. Investigating some aspects of this interaction network, gain- and loss-of-function experiments using small RNA mimics and antisense LNAs, respectively, showed that ectopic tRF-Gly^TCC reduced RUNX2 expression and dispersed 3D micromass architecture in vitro. iCLIP sequencing revealed YBX1 physical binding to the 3' UTR of RUNX2. The interaction between YBX1, tRF-Gly^TCC and RUNX2 led to the development of the RUNX2 inhibitor CADD522 as a PBC treatment. CADD522 assessment in vitro revealed significant effects on PBC cell behaviour. In xenograft mouse models, CADD522 as a single agent without surgery significantly reduced tumour volume, increased overall and metastasis-free survival and reduced cancer-induced bone disease. Our results provide insight into PBC molecular abnormalities that have led to the identification of new targets and a new therapeutic.

Association between toxic metals, vitamin D and preterm birth in the Maternal-Infant research on environmental chemicals study

BACKGROUND

Toxic metals, like lead, are risk factors for preterm birth (PTB), but few studies have examined low levels found in most Canadians. Vitamin D, which may have antioxidant activity, protects against PTB.

OBJECTIVES

In this study, we investigated the impact of toxic metals (lead, mercury, cadmium and arsenic) on PTB and examined if maternal plasma vitamin D concentrations modify these associations.

METHODS

We investigated whether concentrations of metals in whole blood measured in early and late pregnancy were associated with PTB (<37 weeks) and spontaneous PTB in 1851 live births from the Maternal-Infant Research on Environmental Chemicals Study using discrete time survival analysis. We also investigated whether the risk of PTB was modified by first-trimester plasma 25-hydroxyvitamin D (25OHD) concentrations.

RESULTS

Of 1851 live births, 6.1% (n = 113) were PTBs and 4.9% (n = 89) were spontaneous PTB. A 1 μg/dL increase in blood lead concentrations during pregnancy was associated with an increased risk of PTB (relative risk [RR] 1.48, 95% confidence interval [CI] 1.00, 2.20) and spontaneous PTB (RR 1.71, 95% CI 1.13, 2.60). The risk was higher in women with insufficient vitamin D concentrations (25OHD <50 nmol/L) for both PTB (RR 2.42, 95% CI 1.01, 5.79) and spontaneous PTB (RR 3.04, 95% CI 1.15, 8.04). However, an interaction on the additive scale was not present. Arsenic was associated with a higher risk of PTB (RR 1.10, 95% CI 1.02, 1.19) and spontaneous PTB (RR 1.11, 95% CI 1.03, 1.20) per 1 μg/L.

CONCLUSIONS

Gestational exposure to low levels of lead and arsenic may increase the risk of PTB and spontaneous PTB; individuals with insufficient vitamin D may be more susceptible to the adverse effects of lead. Given our relatively small number of cases, we encourage testing of this hypothesis in other cohorts, especially those with vitamin D-deficient populations.

Differences in mirex [dechlorane] and dechlorane plus [syn- and anti-] concentrations observed in Canadian human milk

As part of the pan-Canadian Maternal-Infant Research on Environmental Chemicals (MIREC) study, human milk samples were collected between 2008 and 2011, and analyzed for mirex, an organochlorine insecticide and flame retardant, in addition to dechlorane plus (syn- and anti-DDC-CO), the flame retardant replacement for mirex. Mirex was analyzed separately, using a method for the analysis of existing organochlorine insecticides, while the presence of DDC-CO isomers was determined using a method developed for the detection of emerging flame retardants. Mirex was detected in all samples analyzed (n = 298), while syn- and anti-DDC-CO were present in 61.0% and 79.5% of the samples, respectively (n = 541). Mirex concentrations have declined in human milk since the 1990s. Since this is the first pan-Canadian dataset reporting DDC-CO concentrations in human milk, no temporal comparisons can be made. Maternal age was correlated with concentrations of both compounds although parity did not impact concentrations of either analyte. Given the presence of this relatively recently identified flame retardant (DDC-CO) in human milk from women across Canada, studies to identify dominant sources of this compound are critical. Despite low concentrations of environmental chemicals in human milk from Canadian women, Health Canada supports breastfeeding of infants because of the important health benefits to both the mothers and their infants.

An intergenerational life-course approach to address early childhood obesity and adiposity: the Healthy Life Trajectories Initiative (HeLTI)

BACKGROUND

Interactions between genes and early-life exposures during conception, fetal life, infancy, and early childhood have been shown to affect an individual's health later in life. Maternal undernutrition and obesity, gestational diabetes, and impaired growth in utero and in early life are associated with adiposity and overweight and obesity in childhood, which are risk factors for poor health trajectories and non-communicable diseases. In Canada, China, India, and South Africa, 10-30% of children aged 5-16 years are overweight or obese.

METHODS

The application of developmental origins of health and disease principles offers a novel approach to prevention of overweight and obesity and reduction of adiposity by delivering integrated interventions across the life course, starting before conception and continuing through early childhood. The Healthy Life Trajectories Initiative (HeLTI) was established in 2017 through a unique collaboration between national funding agencies in Canada, China, India, South Africa, and WHO. The aim of HeLTI is to evaluate the effect of an integrated four-phase intervention starting preconceptionally and continuing through pregnancy, infancy, and early childhood on reducing childhood adiposity (fat mass index) and overweight and obesity, and optimising early child development, nutrition, and other healthy behaviours.

FINDINGS

Approximately 22 000 women are being recruited in Shanghai (China), Mysore (India), Soweto (South Africa), and across various provinces of Canada. Women who conceive (an expected 10 000) and their children will be followed up until the child reaches the age of 5 years.

INTERPRETATION

HeLTI has harmonised the intervention, measures, tools, biospecimen collection, and analysis plans for the trial to be run across four countries. HeLTI will help establish whether an intervention aimed at addressing maternal health behaviours, nutrition, and weight; providing psychosocial support to reduce maternal stress and prevent mental illness; optimising infant nutrition, physical activity, and sleep; and promoting parenting skills can reduce the intergenerational risk of excess childhood adiposity and overweight and obesity across diverse settings.

FUNDING

Canadian Institutes of Health Research; National Science Foundation of China; Department of Biotechnology, India; and South African Medical Research Council.

3' Untranslated Region Structural Elements in CYP24A1 Are Associated With Infantile Hypercalcemia Type 1

Loss-of-function mutations in the CYP24A1 protein-coding region causing reduced 25 hydroxyvitamin D (25OHD) and 1,25 dihydroxyvitamin D (1,25(OH)₂ D) catabolism have been observed in some cases of infantile hypercalcemia type 1 (HCINF1), which can manifest as nephrocalcinosis, hypercalcemia and adult-onset hypercalciuria, and renal stone formation. Some cases present with apparent CYP24A1 phenotypes but do not exhibit pathogenic mutations. Here, we assessed the molecular mechanisms driving apparent HCINF1 where there was a lack of CYP24A1 mutation. We obtained blood samples from 47 patients with either a single abnormality of no obvious cause or a combination of hypercalcemia, hypercalciuria, and nephrolithiasis as part of our metabolic and stone clinics. We used liquid chromatography tandem mass spectrometry (LC-MS/MS) to determine serum vitamin D metabolites and direct sequencing to confirm CYP24A1 genotype. Six patients presented with profiles characteristic of altered CYP24A1 function but lacked protein-coding mutations in CYP24A1. Analysis upstream and downstream of the coding sequence showed single nucleotide variants (SNVs) in the CYP24A1 3' untranslated region (UTR). Bioinformatics approaches revealed that these 3' UTR abnormalities did not result in microRNA silencing but altered the CYP24A1 messenger RNA (mRNA) secondary structure, which negatively impacted translation. Our experiments showed that mRNA misfolding driven by these 3' UTR sequence-dependent structural elements was associated with normal 25OHD but abnormal 1,25(OH)₂ D catabolism. Using CRISPR-Cas9 gene editing, we developed an in vitro mutant model for future CYP24A1 studies. Our results form a basis for future studies investigating structure-function relationships and novel CYP24A1 mutations producing a semifunctional protein. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

A harmonized analysis of five Canadian pregnancy cohort studies: exploring the characteristics and pregnancy outcomes associated with prenatal alcohol exposure

BACKGROUND

As a teratogen, alcohol exposure during pregnancy can impact fetal development and result in adverse birth outcomes. Despite the clinical and social importance of prenatal alcohol use, limited routinely collected information or epidemiological data exists in Canada. The aim of this study was to pool data from multiple Canadian cohort studies to identify sociodemographic characteristics before and during pregnancy that were associated with alcohol consumption during pregnancy and to assess the impact of different patterns of alcohol use on birth outcomes.

METHODS

We harmonized information collected (e.g., pregnant women's alcohol intake, infants' gestational age and birth weight) from five Canadian pregnancy cohort studies to consolidate a large sample (n = 11,448). Risk factors for any alcohol use during pregnancy, including any alcohol use prior to pregnancy recognition, and binge drinking, were estimated using binomial regressions including fixed effects of pregnancy cohort membership and multiple maternal risk factors. Impacts of alcohol use during pregnancy on birth outcomes (preterm birth and low birth weight for gestational) were also estimated using binomial regression models.

RESULTS

In analyses adjusting for multiple risk factors, women's alcohol use during pregnancy, both any use and any binge drinking, was associated with drinking prior to pregnancy, smoking during pregnancy, and white ethnicity. Higher income level was associated with any drinking during pregnancy. Neither drinking during pregnancy nor binge drinking during pregnancy was significantly associated with preterm delivery or low birth weight for gestational age in our sample.

CONCLUSIONS

Pooling data across pregnancy cohort studies allowed us to create a large sample of Canadian women and investigate the risk factors for alcohol consumption during pregnancy. We suggest that future pregnancy and birth cohorts should always include questions related to the frequency and amount of alcohol consumed before and during pregnancy that are prospectively harmonized to support data reusability and collaborative research.

Hormonal contraceptive use, bone density and biochemical markers of bone metabolism in British Army recruits

INTRODUCTION

Hormonal contraceptive use might impair bone health and increase the risk of stress fracture by decreasing endogenous oestrogen production, a central regulator of bone metabolism. This cross-sectional study investigated bone density and biochemical markers of bone metabolism in women taking hormonal contraceptives on entry to basic military training.

METHODS

Forty-five female British Army recruits had biochemical markers of bone metabolism, areal bone mineral density (aBMD) and tibial speed of sound (tSOS) measured at the start of basic military training. Participants were compared by their method of hormonal contraception: no hormonal contraception (NONE), combined contraceptive pill (CP) or depot-medroxyprogesterone acetate (DMPA) (20±2.8 years, 1.64±0.63 m, 61.7±6.2 kg).

RESULTS

aBMD was not different between groups (p≥0.204), but tSOS was higher in NONE (3%, p=0.014) when compared with DMPA users. Beta C-terminal telopeptide was higher in NONE (45%, p=0.037) and DMPA users (90%, p=0.003) compared with CP users. Procollagen type 1 N-terminal propeptide was higher in DMPA users compared with NONE (43%, p=0.045) and CP users (127%, p=0.001), and higher in NONE compared with CP users (59%, p=0.014). Bone alkaline phosphatase was higher in DMPA users compared with CP users (56%, p=0.044).

CONCLUSIONS

DMPA use was associated with increased bone turnover and decreased cortical bone integrity of the tibia. Lower cortical bone integrity in DMPA users was possibly mediated by increased intracortical remodelling, but trabecular bone was not affected by contraceptive use.

The effects of collagen peptides on exercise-induced gastrointestinal stress: a randomized, controlled trial

PURPOSE

We examined the effects of collagen peptides (CP) supplementation on exercise-induced gastrointestinal (GI) stress.

METHODS

In a randomized, crossover design, 20 volunteers (16 males: [Formula: see text]O_2max, 53.4 ± 5.9 ml·kg^-1) completed 3 trials: a non-exercise rest trial, with no supplement (REST) and then an exercise trial with CP (10 g·day^-1) or placebo control (CON) supplements, which were consumed for 7 days prior to, and 45 min before, a 70 min run at 70-90% of [Formula: see text]O_2max. Outcome measures included urinary lactulose and rhamnose (L/R), intestinal fatty acid binding protein (I-FABP), lipopolysaccharide (LPS), anti-LPS antibody, monocyte-chemoattractant protein-1 (MCP-1), interleukin (IL) 6 and 8, cortisol, alkaline phosphatase (ALP) (measured pre, 10 min post and 2 h post) and subjective GI symptoms.

RESULTS

There were no differences in heart rate, perceived exertion, thermal comfort, or core temperature during exercise in the CP and CON trials (all P > 0.05). I-FABP was higher in CP (2538 ± 1221 pg/ml) and CON (2541 ± 766 pg/ml) vs. REST 2 h post (1893 ± 1941 pg/ml) (both P < 0.05). LPS increased in CON vs. REST 2 h post (+ 71.8 pg/ml; P < 0.05). Anti-LPS antibody decreased in CON and CP vs. REST at post (both P < 0.05). There were no differences in MCP-1, IL-6, and IL-8 between the CP and CON trials (all P > 0.05), and no differences in L/R or GI symptoms between CON and CP (all P > 0.05).

CONCLUSION

Collagen peptides did not modify exercise-induced changes in inflammation, GI integrity or subjective GI symptoms but LPS was higher in CON 2 h post-exercise and thus future studies may be warranted.

Association between residential proximity to municipal solid waste incinerator sites and birth outcomes in Shanghai: a retrospective cohort study of births during 2014-2018

We tested the hypothesis of whether maternal residential proximity to municipal solid waste incinerator (MSWI) sites could significantly affect birth outcomes. This retrospective birth cohort study conducted at the International Peace Maternity and Infant Hospital, Shanghai, China, included 59,606 mothers with singleton live births during 2014-2018. Multivariate generalized linear models were used to examine associations between residential proximity to MSWI sites and birth outcomes. Small for gestational age (SGA) was significantly more common among children with maternal residential proximity to MSWI sites (odds ratio [OR]=1.20, 95% confidence interval [CI]: 1.07-1.34). Maternal prepregnancy body mass index (BMI) influenced this association. Infants of underweight mothers (prepregnancy BMI <18.5 kg/m2) with MSWI exposure (OR=2.00, 95% CI: 1.58-2.52) had higher risks of SGA than their counterparts. Our findings underscore the need to prevent adverse environmental effects of MSWI on birth outcomes; improved exposure assessment measures are warranted in future studies.

UK national chronic hypoparathyroidism audit

OBJECTIVES

Individuals with chronic hypoparathyroidism may experience suboptimal medical care with high frequency of unplanned hospitalisation and iatrogenic harm. In 2015 the European Society for Endocrinology published consensus guidelines on the management of chronic hypoparathyroidism. We set out to audit compliance with these guidelines.

METHODS

Using these recommendations as audit standards we worked with the Society for Endocrinology and Parathyroid UK to conduct a national audit of management of chronic hypoparathyroidism in the United Kingdom. Endocrine leads in 117 endocrine departments were invited to participate in the survey by completing a data collection tool on up to 5 sequential cases of chronic hypoparathyroidism seen in their outpatient clinics in the preceding 12 months. Data were collected on 4 treatment standards and 9 monitoring standards. Data on hospitalisations and Quality of Life monitoring were also collected.

RESULTS

Responses were received from 22 departments giving a response rate of 19%, concerning 80 individual cases. The mean age of subjects was 48.4 years. The main findings were that the commonest cause of hypoparathyroidism was post surgical (66.3%). Treatments taken by the group included activated vitamin D analogues (96.3%), oral calcium salts (66.3%), vitamin D supplements (17.5%), thiazide diuretics (5%) and rhPTH_1-34 (1.3%). Compliance with the audit standards varied between 98.8% and 60% for the treatment standards and between 91.3% and 20% for the monitoring standards. Some of the areas of weakness revealed include low rates of 24 h urinary calcium excretion monitoring, serum magnesium monitoring and low rates of renal imaging where indicated. In addition and importantly, 16.3% of subjects had experienced at least one hospital admission in the preceding 12 months.

CONCLUSION

We conclude that further improvements in the UK national standard of management of chronic hypoparathyroidism should be made and that this will benefit both quality of life, morbidity and potentially mortality in this group of patients.

Breastfeeding Practices and Associated Factors in Shanghai: A Cross-Sectional Study

The status of breastfeeding practices remains unsatisfactory across China, but regional differences persist. However, disaggregated data for specific provinces are limited. This representative survey determined the status of breastfeeding and factors associated with breastfeeding practices in Shanghai. The questionnaire was designed in compliance with indicators for assessing infant and young child-feeding practices defined by the World Health Organization and the United Nations Children's Fund (UNICEF). A total of 2665 children aged two years and younger (0-730 days) were investigated, among whom 1677 were aged under six months. The early initiation of breastfeeding (EIBF) rate was 60.3%. Among children aged under six months, 43.4% were exclusively breastfed (EBF). The univariate regression analysis showed that the EBF rate was influenced by multiple factors, including individual, socioeconomic, workplace and employment, and health system. The subsequent multivariate analysis suggested that mothers with a higher rate of EBF shared the following characteristics: intention to breastfeed during pregnancy, breastfeeding knowledge, and higher satisfaction with support through the healthcare system after delivery. The rate of EBF in Shanghai is over 40%, and supporting breastfeeding requires measures at multiple levels, including individual attributes, women's work and employment conditions, breastfeeding knowledge, and health services.

Maternal Folate Status and the Relation between Gestational Arsenic Exposure and Child Health Outcomes

Gestational arsenic exposure adversely impacts child health. Folate-mediated 1-carbon metabolism facilitates urinary excretion of arsenic and may prevent arsenic-related adverse health outcomes. We investigated the potential for maternal folate status to modify associations between gestational arsenic exposure and child health. We used data from 364 mother-child pairs in the MIREC study, a prospective pan-Canadian cohort. During pregnancy, we measured first trimester urinary arsenic concentrations, plasma folate biomarkers, and folic acid supplementation intake. At age 3 years, we evaluated twelve neurodevelopmental and anthropometric features. Using latent profile analysis and multinomial regression, we developed phenotypic profiles of child health, estimated covariate-adjusted associations between arsenic and these phenotypic profiles, and evaluated whether folate status modified these associations. We identified three phenotypic profiles of neurodevelopment and three of anthropometry, ranging from less to more optimal child health. Gestational arsenic was associated with decreased odds of optimal neurodevelopment. Maternal folate status did not modify associations of arsenic with neurodevelopmental phenotypic profiles, but gestational arsenic was associated with increased odds of excess adiposity among those who exceed recommendations for folic acid (>1000 μg/day). However, arsenic exposure was low and folate status was high. Gestational arsenic exposure may adversely impact child neurodevelopment and anthropometry, and maternal folate status may not modify these associations; however, future work should examine these associations in more arsenic-exposed or lower folate-status populations.

Perfluorinated alkyl substances in Canadian human milk as part of the Maternal-Infant Research on Environmental Chemicals (MIREC) study

Perfluorinated alkyl substances (PFAS) were determined in human milk samples (n = 664) from participants in the Maternal-Infant Research on Environmental Chemicals (MIREC) study. ΣPFAS concentrations (sum of seven PFAS) ranged from 3.1 ng L^-1 to 603 ng L^-1, with a median concentration of 106 ng L^-1 in the Canadian mothers' milk analyzed. These data comprise the first pan-Canadian dataset of PFAS in human milk. Perfluorooctanoic acid (PFOA) and linear perfluorooctanesulfonate (L-PFOS) were the dominant contributors to ΣPFAS in human milk samples. An inverse relationship between ΣPFAS concentrations and age was observed (Spearman correlation - 0.184). Primiparous women had elevated PFAS concentrations in milk relative to women who had children previously (p < 0.001). In contrast, the region of maternal birth did not influence ΣPFAS concentrations (p = 0.156). Although China and Norway have observed consistently detectable levels of perfluoroundecanoic acid (PFUdA) in human milk, PFAS with long carbon chains (n ≥ 11) were not present above method detection limits in Canadian human milk samples analyzed as part of the MIREC study. In conclusion, despite the presence of low levels of environmental contaminants in human milk, Health Canada supports breastfeeding due to the benefits to both infants and mothers.

Sex differences in tibial adaptations to arduous training: An observational cohort study

Military training increases tibial density and size, but it is unknown if men and women adapt similarly to the same arduous training. Seventy-seven men and 57 women not using hormonal contraceptives completed this study. Tibial volumetric bone mineral density (vBMD) and geometry were measured by peripheral quantitative computed tomography (4%, 14%, 38%, and 66% sites) at the start (week 1) and end (week 14) of British Army basic training. Training increased trabecular vBMD (4% site in men; 4% and 14% sites in women), cortical vBMD (38% site), total area (14% and 38% sites), trabecular area (14% site), cortical area and thickness (14%, 38%, and 66% sites), periosteal perimeter (14%, 38%, and 66% sites), and all indices of estimated strength (14%, 38%, and 66% sites); and, decreased endosteal perimeter (66% site) in men and women (all p ≤ 0.045). The increase in trabecular vBMD (4% and 14% sites) was greater in women and the increases in cortical area and strength (38% site) were greater in men (sex × time interactions, all p ≤ 0.047). P1NP increased and βCTX and sclerostin decreased during training in men and women, consistent with adaptive bone formation. PTH decreased in men but increased in women. Arduous weight-bearing activity increased the density and size of the tibia after 14 weeks. Women experienced similar tibial adaptations as men, however, a greater increase in trabecular vBMD in women compared with men could be due to higher loading at this skeletal site in women, whereas the small increase in cortical area could be due to inhibitory effects of oestradiol.

Transition from preschool to school: Children's pattern of change in morning cortisol concentrations

Many studies show a general increase in stress hormones at the exposure to school entry, but inconsistencies among them due to small samples with varying methodologies and very few time-points, preclude robust conclusions. The current study aimed to describe the pattern of morning cortisol concentration in children across the transition from preschool to school by examining whether we could identify a response to the school entry, but also an anticipatory stress response (pre-entry) and a stress adaptation response (post-entry). We further tested the robustness of this pattern across several characteristics. Participants were 384 children recruited from two cohorts of the 3D pregnancy study, and followed across their transition from preschool to kindergarten. Children's morning salivary cortisol samples were collected over five time-points: twice before school entry, once at school entry and twice after school entry (one sample per time-point). Although no anticipatory stress response was observed two weeks before school entry, latent growth curve models showed that most children's morning cortisol concentrations increased during the first two weeks of school, and was not associated with any sociodemographic characteristics, supporting the hypothesis that school entry is a normative environmental stressor. In contrast, two months after school entry, some children showed stress adaptation whereas others showed a prolonged stress response to school entry. This between-children variance could not be explained by any specific sociodemographic characteristic. This study showed that the morning stress response rises at school entry and is sustained for at least two weeks in most children. However, the observed variability in the stress adaptation response remains to be elucidated and linked to functional correlates.

Vitamin D Supplementation for 12 Months in Older Adults Alters Regulators of Bone Metabolism but Does Not Change Wnt Signaling Pathway Markers

Vitamin D status and supplementation regulates bone metabolism and may modulate Wnt signaling. We studied the response of hormonal regulators of bone metabolism, markers of Wnt signaling and bone turnover and bone mineral density (BMD) and bone mineral content (BMC) in a randomized vitamin D intervention trial (12,000 IU, 24,000 IU, 48,000 IU/mo for 1 year; men and women aged >70 years; n = 379; ISRCTN35648481). Associations with total and free 25(OH)D concentrations were analyzed by linear regression. Baseline vitamin D status was (mean ± SD) 25(OH)D: 40.0 ± 20.1 nmol/L. Supplementation dose-dependently increased total and free 25(OH)D concentrations and decreased plasma phosphate and parathyroid hormone (PTH) (all p < 0.05). The procollagen 1 intact N-terminal (PINP)/C-terminal telopeptide (CTX) ratio, C-terminal fibroblast growth factor-23 (cFGF23), and intact FGF23 (iFGF23) significantly increased with no between-group differences, whereas Klotho was unchanged. 1,25(OH)₂D and PINP significantly increased in the 24 IU and 48,000 IU groups. Sclerostin (SOST), osteoprotegerin (OPG), receptor activator of NF-κB ligand (RANKL), BMD, BMC, and CTX remained unchanged. Subgroup analyses with baseline 25(OH)D <25 nmol/L (n = 94) provided similar results. Baseline total and free 25(OH)D concentrations were positively associated with 1,25(OH)₂D, 24,25(OH)₂D (p < 0.001), vitamin D binding protein (DBP) (p < 0.05), BMD, and BMC (p < 0.05). Associations with PTH (p <0.001), cFGF23 (p < 0.01), and BAP (p < 0.05) were negative. After supplementation, total and free 25(OH)D concentrations remained positively associated only with 24,25(OH)₂D (p < 0.001) and DBP (p < 0.001) and negatively with estimated glomerular filtration rate (eGFR) (p < 0.01). PTH and SOST were significantly associated only with free 25(OH)D. There were no significant relationships with BMD and BMC after supplementation. The decrease in PTH and increase in PINP/CTX ratio suggest a protective effect of supplementation on bone metabolism, although no significant effect on BMD or pronounced changes in regulators of Wnt signaling were found. The increase in FGF23 warrants caution because of its negative association with skeletal and cardiovascular health. Associations of total and free 25(OH)D with biomarkers were similar and known positive associations between vitamin D status and BMD were confirmed. The change in associations after supplementation might suggest a threshold effect. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Prevalence and Determinants of Vitamin D Deficiency in 1825 Cape Town Primary Schoolchildren: A Cross-Sectional Study

Vitamin D deficiency (25-hydroxyvitamin D[25(OH)D] <50 nmol/L) is common among adults in Cape Town, South Africa, but studies investigating vitamin D status of children in this setting are lacking. We conducted a cross-sectional study to determine the prevalence and determinants of vitamin D deficiency in 1825 Cape Town schoolchildren aged 6−11 years. Prevalence of vitamin D deficiency was 7.6% (95% Confidence Interval [CI] 6.5% to 8.9%). Determinants of vitamin D deficiency included month of sampling (adjusted odds ratio [aOR] for July−September vs. January−March 10.69, 95% CI 5.02 to 22.77; aOR for October−December vs. January−March 6.73, 95% CI 2.82 to 16.08), older age (aOR 1.25 per increasing year, 95% CI: 1.01−1.53) and higher body mass index (BMI; aOR 1.24 per unit increase in BMI-for-age Z-score, 95% CI: 1.03−1.49). In a subset of 370 participants in whom parathyroid hormone (PTH) concentrations were measured; these were inversely related to serum 25(OH)D concentrations (p < 0.001). However, no association between participants with hyperparathyroidism (PTH >6.9 pmol/L) and vitamin D deficiency was seen (p = 0.42). In conclusion, we report that season is the major determinant of vitamin D status among Cape Town primary schoolchildren, with prevalence of vitamin D deficiency ranging from 1.4% in January−March to 22.8% in July−September.

Age and vitamin D affect the magnitude of the antibody response to the first dose of the SARS-CoV-2 BNT162b2 vaccine

Background

Most approved vaccines utilise a two-dose strategy. To enable larger groups of patients to receive the first dose, the UK government increased the gap between the two doses from three to twelve weeks. Here we report on the immunogenicity of the first dose, including effect of age and vitamin D status on these levels over an 8 week-period.

Methods

Blood samples were collected from healthcare workers (HCW) receiving their first BNT162b2 vaccine dose between January and February 2021. Antibody (Ab) production was measured, prior to and weekly for 4 weeks post immunization, and a final measurement was performed at 8 weeks. Serum vitamin D concentrations were also measured at baseline.

Findings

Immunization of 97 HCW induced an Ab response that peaked 3•2 weeks post immunization to decrease thereafter. Ab levels remained positive at 8 weeks. IgG peak concentration was negatively associated with age (β=-0•440, p<0.001). Response to immunization was also significantly affected by vitamin D status (p=0•022), on average 29•3% greater peak value in individuals with 25(OH)D>50nmol/L. No other variable showed significant effect.

Interpretation

The first dose of BNT162b2 produced Ab levels that remained positive after 8 weeks. Peak was greater in younger subjects and 25(OH)D>50nmol/L was beneficial. Booster campaigns should take into consideration vitamin D status which is at its highest following a period of sunshine exposure or following oral supplementation (400-1000IU daily).

Funding

Abbott Diagnostics Ltd supplied the kits used to quantify the anti-SARS -CoV-2 Spike IgG and technical support as well as provided financial support for sample collections.

Large-for-Gestational-Age, Leptin, and Adiponectin in Infancy

CONTEXT

Fetal overgrowth "programs" an elevated risk of obesity and type 2 diabetes in adulthood. Plausibly, adipokines may be involved in programming metabolic health.

OBJECTIVE

This work aimed to evaluate whether large-for-gestational-age (LGA), an indicator of fetal overgrowth, is associated with altered circulating leptin and adiponectin levels in infancy, and assess the determinants.

METHODS

In the Canadian 3D birth cohort, we studied 70 LGA (birth weight > 90th percentile) and 140 optimal-for-gestational-age (OGA, 25th-75th percentiles) infants matched by maternal ethnicity, smoking, and gestational age at delivery. The primary outcomes were fasting leptin, and total and high-molecular-weight (HMW) adiponectin concentrations at age 2 years.

RESULTS

LGA infants had higher body mass index (BMI) than OGA infants. However, there were no significant differences in leptin, and total and HMW adiponectin concentrations. Leptin concentrations were positively associated with female sex, weight (z score) gain 0 to 24 months, current BMI, and the sum of triceps and subscapular skinfold thickness, and negatively associated with maternal age and White ethnicity. Female sex was associated with lower total and HMW adiponectin concentrations. Weight (z score) gain 0 to 24 months and current BMI were positively correlated with total and HMW adiponectin concentrations in LGA infants only.

CONCLUSION

This study is the first to demonstrate that LGA does not matter for circulating leptin and adiponectin concentrations in infancy, and there may be LGA-specific positive associations between weight gain or current BMI and adiponectin concentrations in infancy, suggesting dysfunction in establishing the adiposity-adiponectin negative feedback loop in LGA individuals.

Breast-feeding, rapid growth in the first year of life and excess weight at the age of 2 years: the 3D Cohort Study

OBJECTIVE

To assess relationships between breast-feeding, rapid growth in the first year of life and overweight/obesity status at the age of 2 years.

DESIGN

As part of an observational, longitudinal study beginning in early pregnancy, multivariable logistic regressions were used to assess associations between breast-feeding duration (total and exclusive) and rapid weight gain (RWG) between birth and 1 year of age, and to determine predictors of overweight/obesity status at the age of 2 years.

SETTING

Nine hospitals located in the province of Quebec, Canada.

PARTICIPANTS

A sample of 1599 term infants who participated in the 3D Cohort Study.

RESULTS

Children having RWG in the first year and those having excess weight at the age of 2 years accounted for 28 % and < 10 %, respectively. In multivariable models, children breastfed < 6 months and from 6 months to < 1 year were, respectively, 2·5 times (OR 2·45; 95 % CI 1·76, 3·41) and 1·8 times (OR 1·78; 95 % CI 1·29, 2·45) more likely to show RWG up to 1 year of age compared to children breastfed ≥ 1 year. Children exclusively breastfed < 3 months had significantly greater odds of RWG in the first year (OR 1·94; 95 % CI 1·25, 3·04) compared to children exclusively breastfed for ≥ 6 months. Associations between breast-feeding duration (total or exclusive) and excess weight at the age of 2 years were not detected. RWG in the first year was found to be the main predictor of excess weight at the age of 2 years (OR 6·98; 95 % CI 4·35, 11·47).

CONCLUSIONS

The potential beneficial effects of breast-feeding on rate of growth in the first year of life suggest that interventions promoting breast-feeding are relevant for obesity prevention early in life.

Critical Time Windows for Air Pollution Exposure and Birth Weight in a Multicity Canadian Pregnancy Cohort

BACKGROUND

Maternal prenatal exposure to air pollution has been associated with adverse birth outcomes. However, previous studies focused on a priori time intervals such as trimesters reported inconsistent associations.

OBJECTIVES

We investigated time-varying vulnerability of birth weight to fine particulate matter (PM2.5) and nitrogen dioxide (NO2) using flexible time intervals.

METHODS

We analyzed 1,300 live, full-term births from Maternal-Infant Research on Environmental Chemicals, a Canadian prospective pregnancy cohort spanning 10 cities (2008-2011). Daily PM2.5 and NO2 concentrations were estimated from ground-level monitoring, satellite models, and land-use regression, and assigned to participants from pre-pregnancy through delivery. We developed a flexible two-stage modeling method-using a Bayesian Metropolis-Hastings algorithm and empirical density threshold-to identify time-dependent vulnerability to air pollution without specifying exposure periods a priori. This approach identified critical windows with varying lengths (2-363 days) and critical windows that fell within, or straddled, predetermined time periods (i.e., trimesters). We adjusted the models for detailed infant and maternal covariates.

RESULTS

Critical windows associated with reduced birth weight were identified during mid- to late-pregnancy for both PM2.5 and NO2: -6 g (95% credible interval: -11, -1 g) and -5 g (-10, -0.1 g) per µg/m3 PM2.5 during gestational days 91-139 and 249-272, respectively; and -3 g (-5, -1 g) per ppb NO2 during days 55-145.

DISCUSSION

We used a novel, flexible selection method to identify critical windows when maternal exposures to air pollution were associated with decrements in birth weight. Our results suggest that air pollution impacts on fetal development may not be adequately captured by trimester-based analyses.