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.

Effect of Maternal Docosahexaenoic Acid Supplementation on Very Preterm Infant Growth: Secondary Outcome of a Randomized Clinical Trial

INTRODUCTION

The aim of the study was to determine the effect of a maternal docosahexaenoic acid (DHA) supplementation during lactation, compared with a placebo, on the neonatal growth profile of breastfed very preterm infants.

METHODS

Preterm infants' growth profile, growth velocity from birth to 36 weeks' postmenstrual age (PMA), and growth at 36 weeks' PMA were pre-specified secondary outcomes of a randomized placebo-controlled trial conducted in 16 Canadian neonatal intensive care units (2015-2018). Lactating mothers who delivered before 29 weeks' gestation were given 1.2 g of DHA daily or a placebo within 72 h of delivery and up to 36 weeks' PMA. Analyses were performed using a linear regression model with generalized estimating equations.

RESULTS

461 mothers and their 528 infants (DHA, N = 273; placebo, N = 255) were included with mean gestational age of 26.5 weeks (standard deviation [SD] = 1.6); 275 (52.1%) were males; mean birth weight was 895 g (SD = 240). DHA interaction with sex was significant on weight profile (interaction p < 0.001), weight velocity (interaction p = 0.05), and weight at 36 weeks' PMA (interaction p = 0.02). Females in the DHA group gained more weight compared to the placebo group (mean difference [MD], 52.6 g [95% confidence interval [CI]: 24.5-80.8], p < 0.001). Weight velocity was significantly higher in females of the DHA group (MD, 3.4 g/kg/day [95% CI: 0.6-6.2], p = 0.02). At 36 weeks' PMA, the weight of males in the DHA group was significantly smaller (MD, -88.9 g [95% CI: -166.2 to -11.6], p = 0.02).

CONCLUSION

DHA positively affected female infants' neonatal weight profile and velocity and negatively affected male infants' weight at 36 weeks' PMA.

Sedentary behaviour and bone health in older adults: a systematic review

Older adults spend more than 8 h/day in sedentary behaviours. Detrimental effects of sedentary behaviour (SB) on health are established, yet little is known about SB and bone health (bone mineral density; BMD) in older adults. The purpose of this review is to examine associations of SB with BMD in older adults. Five electronic databases were searched: Web of Science (Core Collection); PubMed; EMBASE; Sports Medicine and Education and PsycInfo. Inclusion criteria were healthy older adults mean age ≥ 65 years; measured SB and measured BMD using dual-energy X-ray absorptiometry. Quality was assessed using National Institute of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. After excluding duplicates 17813 papers were assessed; 17757 were excluded on title/abstract, 49 at full text, resulting in two prospective and five cross-sectional observational studies reviewed. Four were rated 'good' and three were rated 'fair' using the quality assessment criteria. Findings varied across the studies and differed by gender. In women, four studies reported significant positive associations of SB with BMD at different sites, and two found significant negative associations. Five studies which examined both men and women, men reported negative or no associations of SB with femoral neck, pelvic, whole body, spine or leg BMD. Whilst these findings suggest differences between men and women in the associations of SB with BMD, they may be due to the varying anatomical sections examined for BMD, the different methods used to measure SB, the varied quality of the studies included and the limited number of published findings.

The effects of short-term low energy availability, achieved through diet or exercise, on cognitive function in oral contraceptive users and eumenorrheic women

To date, no research has explored the effects of low energy availability on cognitive performance using dietary and exercise regimens relevant to athletes. Twenty female participants (10 eumenorrheic, 10 oral contraceptive [OC] users) completed three 3-day conditions: 1) controlled-balanced energy availability without exercise (BAL; 45 kcal·kg lean body mass [LBM]^-1·day^-1); 2) diet-induced low energy availability without exercise (DIET; 15 kcal·kg LBM^-1·day^-1); and 3) exercise-induced low energy availability (EX; 15 kcal·kg LBM^-1·day^-1, including 30 kcal·kg LBM^-1·day^-1 treadmill running at 70% maximal oxygen uptake). A cognitive test battery was completed before and after each 3-day condition. Mental rotation test accuracy improved in the BAL condition, but there was a decline in accuracy in the EX condition (BAL, +2.5%; EX, -1.4%; P = 0.042, d = 0.85). DIET (+1.3%) was not different to BAL or EX (P > 0.05). All other measures of cognitive performance were not affected by condition (P > 0.05) and OC use did not affect cognitive responses (P > 0.05). Accuracy in the mental rotation test was impaired when low energy availability was induced through increased exercise energy expenditure. All other aspects of cognition were unaffected by 3 days of low energy availability through diet or exercise. OC use did not mediate the effect of low energy availability on cognition. Novelty: Cognitive function was not affected by 3 days of diet-induced low energy availability. Only spatial awareness was impaired during 3 days of exercise-induced low energy availability. Reproductive hormones affected spatial awareness independent of energy availability.

Dental amalgams and risk of gestational hypertension in the MIREC study

BACKGROUND

The potential association between the presence or replacement of dental amalgams and gestational hypertension (GH) is unclear.

OBJECTIVE

To assess the association between the presence or replacement of dental amalgams and the risk of GH in a prospective cohort study.

METHODS

We assessed dental amalgam status (presence or replacement), blood mercury concentrations, and measured blood pressure (BP) in 1817 pregnant women recruited in 10 Canadian cities. BP was assessed in each trimester of pregnancy and mercury concentrations in 1st and 3rd trimesters. Logistic regression analysis was performed to estimate the adjusted odds ratios (aOR) and 95% confidence intervals (CI) for the associations between dental amalgam status and GH. Concurrent measures with systolic BP (SBP) and diastolic BP (DBP) were assessing through linear generalized estimating equations.

RESULTS

Dental amalgam status was weakly statistically correlated with mercury concentrations but there was no evidence of an association with GH in women having 1-4 (aOR = 1.31 (0.92, 1.85)) or ≥ 5 dental amalgams (aOR = 1.32 (0.86, 2.04)), compared to women without amalgam reported at first trimester. Dental amalgam replacement reported in the first or third trimester was similarly not associated with GH (aOR = 0.75 (0.40, 1.42) and 0.73 (0.39, 1.34), respectively) but with SBP (beta = -1.58 (-2.95, -0.02)).

CONCLUSION

We found weak correlations between dental amalgams and blood mercury among pregnant women. However, the presence of dental amalgams or their replacement was not associated with GH but with decreased SBP for the replacement. Further studies are required.

Gestational hypercalcemia: Prevalence and biochemical profile

Gestational hypercalcemia is associated with an increased risk of maternal, fetal and neonatal morbidity and mortality. Hypercalcemia may develop during pregnancy in individuals who were previously asymptomatic. The increased sensitivity during pregnancy may be related to physiological, gestational alterations in vitamin D and calcium metabolism and may be influenced by gene variants. The prevalence is unknown. We investigated the prevalence of hypercalcemia in trimester 3 (T3) in a population representative prospective cohort study (n = 1832) in South-West Sweden. Women with serum albumin (Alb) adjusted calcium (Ca_Alb) ≥ 2.65 mmol/L in T3 (n = 30) were matched to normo-calcemic controls, and markers of calcium and vitamin D metabolism were investigated in trimester 1 (T1) and T3. Serum concentrations of Ca, phosphate (P), Magnesium (Mg), Alb and creatinine (Cr), parathyroid hormone (PTH; T3 only), vitamin D metabolites (total 25(OH)D, 1,25(OH)₂D, 24,25(OH)₂D, and free 25(OH)D) were analysed in T1 and T3. Ca_Alb (Payne; inter-laboratory difference: UEA = 0.15 + 0.9*UGOT; UEA 2.54 = UGOT 2.65) and estimated glomerular filtration rate (eGFR; modified 4-variable MDRD) and vitamin D metabolites ratios (VMR) were calculated. Normally and non-normally distributed data were presented as mean (SD) or median (95 %CI). Group differences in relationships between vitamin D metabolites and with PTH were investigated with multiple regression analyses. Hypercalcemia in T3 was found in 1.7 % of women. PTH concentrations suggestive of primary hyperparathyroidism was found in 1 woman and none had 25(OH)D or 24,25(OH)₂D concentrations in the toxicity range or suggestive of mutations in the CYP24A1 gene. Ca_Alb was significantly higher in hypercalcemic cases compared to controls in T1 (2.44 (2.30-2.80) vs 2.37 (2.25-2.49) mmol/L) and T3 (2.63 (2.52-2.78) vs 2.46 (2.31-2.58) mmol/L). Serum P was higher among cases than controls in T3 (1.12 (0.16) vs 1.07 (0.18) mmol/L) but not in T1 (1.12 (0.18) and 1.12 (0.16) mmol/L). PTH in T3 was lower in cases (1.6 (1.6-2.8) vs 2.3 (2.1-2.8) pmol/L) but 1,25(OH)₂D concentrations were similar. There were no significant group differences in serum 25(OH)D, free 25(OH)D, 24,25(OH)₂D, Mg, Alb, Cr and eGFR. Regression analyses did not show significant differences between cases and controls in relationships between vitamin D metabolites and with PTH, except for the free 25(OH)D-PTH relationship and a higher free:total 25(OH)D ratio in cases at T1. In conclusion, most common causes of hypercalcemia were excluded in the majority of women. Hypercalcemic women had a relatively high serum 1,25(OH)₂D concentration despite an appropriately suppressed PTH, suggestive of abnormal gestational adaptions.

Associations between Maternal Exposure to Bisphenol A or Triclosan and Gestational Hypertension and Preeclampsia: The MIREC Study

BACKGROUND

Little is known about the association between bisphenol A (BPA) or triclosan (TCS) exposure and hypertension in pregnancy.

OBJECTIVE

To investigate potential associations between maternal urinary concentrations of BPA or TCS and gestational hypertension (GH) and preeclampsia.

STUDY DESIGN

Among 1,909 pregnant women participating in the maternal-infant research on environmental chemicals (MIREC) study, urinary concentrations of BPA and TCS were measured in the first trimester by liquid chromatography-tandem mass spectrometry using isotope dilution. Blood pressure was measured during each trimester. Multinomial regression was performed to estimate the adjusted odds ratio (aOR) and 95% confidence intervals (CI) for the associations between these phenols and GH and preeclampsia.

RESULTS

BPA and TCS were not associated with GH or preeclampsia. However, in multiparous women, BPA (0.50-1.30 µg/L) was associated with decreased risk of GH (aOR =0.45; 95%CI: 0.21-0.98) while among nulliparous women, TCS was associated with an increased risk of GH (3.60-32.60 µg/L; aOR = 2.58; 95% CI: 1.09-6.13 and > 32.60 µg/L: aOR = 2.74; 95% CI: 1.15-6.51).

CONCLUSION

BPA and TCS urinary concentrations were not associated with GH or preeclampsia; however, our results suggest an association between TCS and GH in nulliparous women. Additional studies are required to confirm our results.

Cord blood insulin, IGF-I, IGF-II, leptin, adiponectin and ghrelin, and their associations with insulin sensitivity, β-cell function and adiposity in infancy

AIM

Vulnerability to insulin resistance and Type 2 diabetes may originate in early life, but little is known about whether any perinatal biomarkers are predictive of later metabolic health. We sought to assess whether cord blood insulin, insulin-like growth factor (IGF)-I, IGF-II, leptin, adiponectin and ghrelin are associated with metabolic health indicators in infancy.

METHODS

In a prospective singleton birth cohort, we assessed cord blood insulin, IGF-I, IGF-II, leptin, adiponectin and ghrelin concentrations in relation to the homeostasis model assessment of insulin resistance (HOMA-IR), β-cell function (HOMA-β), fasting proinsulin-to-insulin ratio, BMIz-score, and the sum of triceps and subscapular skinfold thickness (an indicator of adiposity) in infants at age 1 year (n = 185).

RESULTS

Adjusting for maternal and infant characteristics, one standard deviation (sd) increase in cord blood adiponectin was associated with an 11.1% (95% confidence interval 1.8-19.5%) decrease in HOMA-β (P = 0.02) and a 13.6% (1.8-26.8%) increase in proinsulin-to-insulin ratio (P = 0.02), indicating worse β-cell function in infants at age 1 year. One sd increase in cord blood insulin was associated with a 0.5 (0.1-1.0) mm increase in skinfold thickness (P = 0.01). One sd increase in cord blood ghrelin was associated with a 0.2 (0.02-0.3) decrease in BMIz-score (P = 0.02) and a 0.5 (0.1-0.9) mm decrease (P = 0.02) in skinfold thickness. Cord blood IGF-I and IGF-II were not associated with the observed metabolic health indicators at age 1 year.

CONCLUSION

The study is the first to show that cord blood adiponectin may be negatively predictive of β-cell function, whereas cord blood ghrelin may be negatively predictive of adiposity in infancy.

Vaginal microbiome in early pregnancy and subsequent risk of spontaneous preterm birth: a case-control study

OBJECTIVES

To explore differences in the vaginal microbiome between preterm and term deliveries.

DESIGN

Nested case-control study in 3D cohort (design, develop, discover).

SETTING

Quebec, Canada.

SAMPLE

Ninety-four women with spontaneous preterm birth as cases [17 early (<34 weeks) and 77 late (34-36 weeks) preterm birth] and 356 women as controls with term delivery (≥37 weeks).

METHODS

To assess the vaginal microbiome by sequencing the V4 region of the 16S ribosomal RNA (rRNA) gene in swabs self-collected during early pregnancy.

MAIN OUTCOME MEASURES

Comparison of relative abundance of bacterial operational taxonomic units and oligotypes and identifying vaginal community state types (CSTs) in early or late spontaneous preterm and term deliveries.

RESULTS

Lactobacillus gasseri/ Lactobacillus johnsonii (coefficient -5.36, 95% CI -8.07 to -2.65), Lactobacillus crispatus (99%)/ Lactobacillus acidophilus (99%) (-4.58, 95% CI -6.20 to -2.96), Lactobacillus iners (99%)/ Ralstonia solanacearum (99%) (-3.98, 95% CI -6.48 to -1.47) and Bifidobacterium longum/ Bifidobacterium breve (-8.84, 95% CI -12.96 to -4.73) were associated with decreased risk of early but not late preterm birth. Six vaginal CSTs were identified: four dominated by Lactobacillus; one with presence of bacterial vaginosis-associated bacteria (Gardnerella vaginalis, Atopobium vaginae and Veillonellaceae bacterium) (CST IV); and one with nondominance of Lactobacillus (CST VI). CST IV was associated with increased risk of early (4.22, 95% CI 1.24-24.85) but not late (1.63, 95% CI 0.68-5.04) preterm birth, compared with CST VI.

CONCLUSIONS

Lactobacillus gasseri/L. johnsonii, L. crispatus/L. acidophilus, L. iners/R. solanacearum and B. longum/B. breve may be associated with decreased risk of early preterm birth. A bacterial vaginosis-related vaginal CST versus a CST nondominated by Lactobacillus may be associated with increased risk of early preterm birth.

TWEETABLE ABSTRACT

Largest study of its kind finds certain species of vaginal Lactobacillus + Bifidobacterium may relate to lower risk of preterm birth.

Longevity of daily oral vitamin D3 supplementation: differences in 25OHD and 24,25(OH)2D observed 2 years after cessation of a 1-year randomised controlled trial (VICtORy RECALL)

To determine how long vitamin D lasts after supplementation ceases, the marker of status was measured 2 and 3 years after a 1-year trial. Compared to placebo, the proportion of vitamin D-deficient women was still lower, if they had taken daily vitamin D3, after 2 years, indicating its longevity.

INTRODUCTION

The purpose of this study was to determine longevity of vitamin D status following cessation of vitamin D3 supplementation, 2 and 3 years after a 1-year randomised, double-blind placebo controlled trial and to investigate possible predictive factors.

METHODS

Caucasian non-smoking postmenopausal women randomised to ViCtORY (2009-2010), who had not taken vitamin D supplements since the trial ended, were invited to attend follow-up visits. Total 25-hydroxyvitamin D (25OHD) and 24,25-dihydroxyvitamin D (24,25OH2D) were measured by dual tandem mass spectrometry of serum samples following removal of protein and de-lipidation; the original randomised controlled trial (RCT) samples were re-analysed simultaneously. Vitamin D-binding protein (VDBP) was measured by monoclonal immunoassay.

RESULTS

In March 2012 and March 2013, 159 women (mean (SD) age 67.6 (2.1) years) re-attended, equally distributed between the original treatment groups: daily vitamin D3 (400 IU, 1000 IU) and placebo. One month after the RCT ended (March 2010), the proportion of women in placebo, 400 IU and 1000 IU vitamin D3 groups, respectively, with 25OHD < 25 nmol/L was 15, 0 and 0 (chi-square p < 0.001, n = 46, 44, 54). After 2 years (March 2012), it was 22, 4 and 4% (p = 0.002, n = 50, 48, 57); after 3 years, it was 23, 13 and 15% (p = 0.429, n = 48, 45, 52). The respective proportions of women with 24,25OH2D < 2.2 nmol/L were 50, 2 and 2% (1 month, p < 0.001, n = 46, 44, 54); 42, 33 and 12% (2 years, p = 0.002, n = 50, 48, 57); and 45, 27 and 29% (3 years, p = 0.138, n = 47, 45, 51). VDBP was a predictor of circulating 25OHD longevity (beta for VDBP in μg/mL 0.736; 95% CI 0.216-1.255, p = 0.006) but not 24,25OH2D.

CONCLUSION

Four hundred international units or 1000 IU of daily vitamin D3 showed benefits over placebo 2 years after supplementation ceased in keeping 25OHD > 25 nmol/L.

Does regional loss of bone density explain low trauma distal forearm fractures in men (the Mr F study)?

The pathogenesis of low trauma wrist fractures in men is not fully understood. This study found that these men have lower bone mineral density at the forearm itself, as well as the hip and spine, and has shown that forearm bone mineral density is the best predictor of wrist fracture.

INTRODUCTION

Men with distal forearm fractures have reduced bone density at the lumbar spine and hip sites, an increased risk of osteoporosis and a higher incidence of further fractures. The aim of this case-control study was to investigate whether or not there is a regional loss of bone mineral density (BMD) at the forearm between men with and without distal forearm fractures.

METHODS

Sixty-one men with low trauma distal forearm fracture and 59 age-matched bone healthy control subjects were recruited. All subjects underwent a DXA scan of forearm, hip and spine, biochemical investigations, health questionnaires, SF-36v2 and Fracture Risk Assessment Tool (FRAX). The non-fractured arm was investigated in subjects with fracture and both forearms in control subjects.

RESULTS

BMD was significantly lower at the ultradistal forearm in men with fracture compared to control subjects, in both the dominant (mean (SD) 0.386 g/cm² (0.049) versus 0.436 g/cm² (0.054), p < 0.001) and non-dominant arm (mean (SD) 0.387 g/cm² (0.060) versus 0.432 g/cm² (0.061), p = 0.001). Fracture subjects also had a significantly lower BMD at hip and spine sites compared with control subjects. Logistic regression analysis showed that the best predictor of forearm fracture was ultradistal forearm BMD (OR = 0.871 (0.805-0.943), p = 0.001), with the likelihood of fracture decreasing by 12.9% for every 0.01 g/cm² increase in ultradistal forearm BMD.

CONCLUSIONS

Men with low trauma distal forearm fracture have significantly lower regional BMD at the ultradistal forearm, which contributes to an increased forearm fracture risk. They also have generalised reduction in BMD, so that low trauma forearm fractures in men should be considered as indicator fractures for osteoporosis.

Habitual levels of higher, but not medium or low, impact physical activity are positively related to lower limb bone strength in older women: findings from a population-based study using accelerometers to classify impact magnitude

This study assessed the effect of accelerometry-measured higher impacts resulting from habitual weight-bearing activity on lower limb bone strength in older women. Despite higher impacts being experienced rarely in this population-based cohort, positive associations were observed between higher vertical impacts and lower limb bone size and strength.

INTRODUCTION

We investigated whether the benefit of habitual weight-bearing physical activity (PA) for lower limb bone strength in older women is explained by exposure to higher impacts, as previously suggested by observations in younger individuals.

METHODS

Four hundred and eight women from the Cohort for Skeletal Health in Bristol and Avon (COSHIBA), mean 76.8 years, wore tri-axial accelerometers at the waist for a mean of 5.4 days. Y-axis peaks were categorised, using previously identified cutoffs, as low (0.5-1.0 g), medium (1.0-1.5 g), and higher (≥1.5 g) impacts. Mid and distal peripheral quantitative computed tomography scans of the tibia and radius were performed, as were hip and lumbar spine Dual X-ray Absorptiometry (DXA) scans. Regressions between (log transformed) number of low, medium and high impacts, and bone outcomes were adjusted for artefact error grade, age, height, fat and lean mass and impacts in other bands.

RESULTS

Eight thousand eight hundred and nine (4047, 16,882) low impacts were observed during the measurement week, 345 (99, 764) medium impacts and 42 (17, 106) higher impacts (median with 25th and 75th quartiles). Higher vertical impacts were positively associated with lower limb bone strength as reflected by cross-sectional moment of inertia (CSMI) of the tibia [0.042 (0.012, 0.072) p = 0.01] and hip [0.067 (0.001, 0.133) p = 0.045] (beta coefficients show standard deviations change per doubling in impacts, with 95 % confidence interval). Higher impacts were positively associated with tibial periosteal circumference (PC) [0.015 (0.003, 0.027) p = 0.02], but unrelated to hip BMD. Equivalent positive associations were not seen for low or medium impacts.

CONCLUSIONS

Despite their rarity, habitual levels of higher impacts were positively associated with lower limb bone size and strength, whereas equivalent relationships were not seen for low or medium impacts.

The relationship between vitamin D status and muscle strength in young healthy adults from sunny climate countries currently living in the northeast of Scotland

The current study examined the relationship between vitamin D status and muscle strength in young healthy adults: residents (>6 months) and newcomers (0-3 months), originally from sunny climate countries but currently living in the northeast of Scotland. Our longitudinal data found a positive, albeit small, relationship between vitamin D status and knee extensor isometric strength.

INTRODUCTION

Vitamin D has been suggested to play a role in muscle health and function, but studies so far have been primarily in older populations for falls prevention and subsequent risk of fractures.

METHODS

Vitamin D status was assessed in a healthy young adults from sunny climate countries (n = 71, aged 19-42 years) with 56% seen within 3 months of arriving in Aberdeen [newcomers; median (range) time living in the UK = 2 months (9-105 days)] and the remainder resident for >6 months [residents; 23 months (6-121 months)]. Participants attended visits every 3 months for 15 months. At each visit, fasted blood samples were collected for analysis of serum 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), carboxy-terminal collagen crosslinks (CTX) and N-terminal propeptide of type I collagen (P1NP). Maximal voluntary contractions (MVC) were performed for grip strength (both arms) and for maximal isometric strength of the knee extensors (right knee).

RESULTS

There were small seasonal variations in 25(OH)D concentrations within the newcomers and residents, but no seasonal variation in bone turnover markers. There was a positive, albeit small, association between 25(OH)D and knee extensor maximal isometric strength. Mixed modelling predicted that for each 1 nmol/L increase in 25(OH)D, peak torque would increase by 1 Nm (p = 0.04).

CONCLUSIONS

This study suggests that vitamin D may be important for muscle health in young adults migrating from sunnier climates to high latitudes, yet the potential effect is small.

High Bone Mass is associated with bone-forming features of osteoarthritis in non-weight bearing joints independent of body mass index

OBJECTIVES

High Bone Mass (HBM) is associated with (a) radiographic knee osteoarthritis (OA), partly mediated by increased BMI, and (b) pelvic enthesophytes and hip osteophytes, suggestive of a bone-forming phenotype. We aimed to establish whether HBM is associated with radiographic features of OA in non-weight-bearing (hand) joints, and whether such OA demonstrates a bone-forming phenotype.

METHODS

HBM cases (BMD Z-scores≥+3.2) were compared with family controls. A blinded assessor graded all PA hand radiographs for: osteophytes (0-3), joint space narrowing (JSN) (0-3), subchondral sclerosis (0-1), at the index Distal Interphalangeal Joint (DIPJ) and 1st Carpometacarpal Joint (CMCJ), using an established atlas. Analyses used a random effects logistic regression model, adjusting a priori for age and gender. Mediating roles of BMI and bone turnover markers (BTMs) were explored by further adjustment.

RESULTS

314 HBM cases (mean age 61.1years, 74% female) and 183 controls (54.3years, 46% female) were included. Osteophytes (grade≥1) were more common in HBM (DIPJ: 67% vs. 45%, CMCJ: 69% vs. 50%), with adjusted OR [95% CI] 1.82 [1.11, 2.97], p=0.017 and 1.89 [1.19, 3.01], p=0.007 respectively; no differences were seen in JSN. Further adjustment for BMI failed to attenuate ORs for osteophytes in HBM cases vs. controls; DIPJ 1.72 [1.05, 2.83], p=0.032, CMCJ 1.76 [1.00, 3.06], p=0.049. Adjustment for BTMs (concentrations lower amongst HBM cases) did not attenuate ORs.

CONCLUSIONS

HBM is positively associated with OA in non-weight-bearing joints, independent of BMI. HBM-associated OA is characterised by osteophytes, consistent with a bone-forming phenotype, rather than JSN reflecting cartilage loss. Systemic factors (e.g. genetic architecture) which govern HBM may also increase bone-forming OA risk.

Current assays overestimate 25-hydroxyvitamin D3 and underestimate 25-hydroxyvitamin D2 compared with HPLC: need for assay-specific decision limits and metabolite-specific assays

Background: Clinical demand for quick, cheap, precise and accurate 25-hydroxyvitamin D (25(OH)D) results has led to the development of a variety of assay methods. Lack of standardization of these methods has resulted in intermethod disagreement and challenged whether current assays recognize 25(OH)D2 and 25(OH)D3 equally.

Methods: We studied 172 patient samples from hip fracture cases using DiaSorin (DS) and IDS radioimmunoassays and the Nichols Advantage-automated protein binding assay (NA-CLPBA) in comparison to high-performance liquid chromatography (HPLC). 52 patient samples were analysed before and after three months treatment with 1000 IU of daily ergocalciferol (vitamin D2).

Results: Linear regression analysis in pre-treatment samples demonstrated a positive Y-intercept for each immunoassay compared with HPLC, and a slope that varied from 0.64 (IDS) to 0.97 (DS, NA-CLPBA). Bland Altman analysis demonstrated that all the three assays had a proportional positive bias relative to HPLC at values from 20 to 50 nmol/L. Regression analysis of post-treatment samples demonstrated a slope that was not significantly different from zero for the IDS and NA-CLPBA and 0.2 for the DS method, with a positive intercept for all assays of between 8 and 22, indicating less than 50% of 25(OH)D2 measured by HPLC was detected.

Conclusions: These results demonstrate the need for assay-specific decision limits for 25(OH)D3 in order to define appropriate thresholds for treatment institution. Treatment with vitamin D2 may not be accurately monitored with any of the three commercial assays studied. Clinicians and biochemists who continue to use 25(OH)D assays need to be urgently informed of these issues.

Longitudinal circulating concentrations of long-chain polyunsaturated fatty acids in the third trimester of pregnancy in gestational diabetes

AIM

Gestational diabetes mellitus is a common complication of pregnancy. Long-chain polyunsaturated fatty acids (LCPUFA) are essential for fetal neurodevelopment. Docosahexaenoic acid (DHA) is the predominant n-3 LCPUFA in the brain and retina. Circulating absolute concentrations of total n-3 and n-6 LCPUFAs rise during normal pregnancy. It remains unclear whether gestational diabetes may affect the normal rise in circulating concentrations of LCPUFAs in the third trimester of pregnancy - a period of rapid fetal neurodevelopment. This study aimed to address this question.

METHODS

In a prospective singleton pregnancy cohort, fatty acids in fasting plasma total lipids were measured at 24-28 and 32-35 weeks of gestation in women with (n = 24) and without gestational diabetes mellitus (n = 116). Fatty acid desaturase activity indices were estimated by relevant product-to-precursor fatty acid ratios. Dietary nutrient intakes were estimated by a food frequency questionnaire.

RESULTS

Plasma absolute concentrations of total n-6 LCPUFAs rose significantly between 24-28 and 32-35 weeks of gestation in women with or without gestational diabetes, whereas total n-3 LCPUFAs and DHA concentrations rose significantly only in women without gestational diabetes (all P < 0.01). Delta-5 desaturase indices (20:4n-6/20:3n-6) were similar, but delta-6 desaturase indices (18:3n-6/18:2n-6) were significantly lower in women with gestational diabetes at 32-35 weeks of gestation. Dietary intakes of all fatty acids were comparable.

CONCLUSION

The normal rise in circulating absolute concentrations of DHA and total n-3 LCPUFAs in the third trimester of pregnancy may be compromised in gestational diabetes, probably due to impaired synthesis or mobilization rather than dietary intake difference.

Female digit length ratio (2D:4D) and time-to-pregnancy

STUDY QUESTION

Is the female 2th- to 4th-finger ratio (2D:4D) associated with fecundity as measured by time-to-pregnancy (TTP)?

SUMMARY ANSWER

Our study does not support an association between female 2D:4D and TTP.

WHAT IS KNOWN ALREADY

The 2th- to 4th-finger ratio (2D:4D) has been proposed as a potential indicator of greater androgen exposure during fetal development. Women exposed in utero to unbalanced steroid hormones may have impaired fecundity in the adulthood. Fecundity is often measured by TTP, an epidemiological tool commonly used to assess the impact of environmental factors in human conception.

STUDY DESIGN, SIZE, DURATION

The Maternal-Infant Research on Environmental Chemicals (MIREC) Study is a pregnancy and birth cohort of 2001 women recruited before 14 weeks of gestation in 10 cities across Canada between 2008 and 2011. The present analysis is part of MIREC-CD Plus, a follow-up study in a subsample of some 800 MIREC mothers and their children from 2012 to 2015.

PARTICIPANTS/MATERIALS, SETTING, METHODS

TTP and maternal characteristics were collected from questionnaires administered during the first trimester of pregnancy as part of the MIREC study. Digital pictures of the ventral surface of both hands were obtained in the MIREC mothers at the MIREC-CD Plus follow-up study. The 2D:4D was calculated as the ratio of the second and fourth fingers of each hand. The exposure of interest was the 2D:4D of the women categorized by tertiles, or dichotomized as ≥1 (index finger longer than the ring finger) or <1 (ring finger longer than the index finger, implying greater androgen exposure during fetal development). The final sample included 696 mothers. Statistical analyses included discrete-time Cox proportional hazard models, allowing adjustment for potential confounding factors.

MAIN RESULTS AND THE ROLE OF CHANCE

There was no evidence of diminished/increased fecundability according to the 2D:4D, neither on the right nor on the left hand. In our analysis by tertiles, the smallest 2D:4D (i.e. higher androgen exposure during fetal life) resulted in FORs higher than 1 (i.e. shorter TTP) in both hands, although this was not statistically significant (FOR 1.19 [95% CI 0.93, 1.51] in the right hand and 1.16 [95% CI 0.91, 1.47] in the left hand). In the dichotomous analysis, 2D:4D <1 resulted in FORs higher than 1 (i.e. shorter TTP), but this was also not statistically significant (FOR 1.08 [95% CI 0.88, 1.33] in the right hand and 1.14 [95% CI 0.92, 1.42] in the left hand). Our large sample size resulted in a high statistical power to exclude an association between female 2D:4D and TTP.

LIMITATIONS, REASONS FOR CAUTION

The MIREC Study is a cohort of pregnant women, and therefore, women with infertility were excluded by design from our study.

WIDER IMPLICATIONS OF THE FINDINGS

Our data do not provide evidence for an association between female 2D:4D and fecundity as measured by TTP. Whether the female 2D:4D is a marker of in utero androgen exposure and whether it is associated with fecundity have yet to be determined.

STUDY FUNDING/COMPETING INTEREST

The MIREC Study was funded by Health Canada's Chemicals Management Plan, the Canadian Institute of Health Research (CIHR grant # MOP - 81285), and the Ontario Ministry of the Environment. MIREC-CD Plus was funded by Health Canada's Chemicals Management Plan Research Fund. The 2D:4D component was funded by a research grant from the CIHR-Quebec Training Network in Perinatal Research (QTNPR). M.P. Vélez was supported by a CIHR Fellowship Award, and a QTNPR scholarship. P. Monnier is supported by the Research Institute of the McGill University Health Centre. W.D Fraser is supported by a CIHR Canada Research Chair. There are no conflicts of interest to declare.

Mental Health Disorders Among Women Victims of Conflict-Related Sexual Violence in the Democratic Republic of Congo

To assess the effects of sexual violence (SV) in armed conflicts on women's mental health, on its own and in conjunction with reproductive health issues such as fistula or chronic pelvic pain (CPP). A cross-sectional population-based study of 320 women living in Goma, the Democratic Republic of Congo, aged 15 to 45 years, was conducted. Women who experienced conflict-related sexual violence (CRSV) were compared with those who experienced non-conflict-related sexual violence (NCRSV) and those who never experienced such acts. Data were gathered through individual interviews by local staff using standardized questionnaires. The outcomes investigated were post-traumatic stress disorder (PTSD) symptoms severity and psychological distress symptoms (PDS) severity. Experience of SV in either context was associated with more severe PDS (p < .0001). Only CRSV was associated with more severe PTSD symptoms (p < .0001). Women who suffered from fistula or CPP also had a higher PDS score mean (p < .0001 and p = .007) and a higher PTSD symptoms score mean (p < .0001, for both reproductive health issues). Multivariate analyses showed that compared with women who never experienced SV and never suffered from fistula or CPP, those who experienced CRSV and suffered from fistula or CPP had the most severe PDS and PTSD symptoms after adjustment for potential confounders. The differences in PDS and PTSD symptoms severity were all significant (p < .0001). Psychological and physical health care are urgently needed for women who experienced CRSV, particularly those with additional issues of fistula or CPP. Current interventions should simultaneously seek to improve both reproductive and mental health.

Maternal exposure to perfluorinated chemicals and reduced fecundity: the MIREC study

STUDY QUESTION

What is the effect of maternal exposure to perfluorooctane sulfonate (PFOS), perflurooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS) on female fecundity?

SUMMARY ANSWER

Increasing concentrations of PFOA or PFHxS in maternal plasma were associated with reduced fecundability and infertility.

WHAT IS KNOWN ALREADY

Perfluorinated chemicals (PFCs) are a group of synthetic compounds used in industrial production. There is a concern about the effect of PFCs on fecundity, as measured by time-to-pregnancy (TTP). Although some recent studies suggest that increasing concentrations of PFCs may decrease fecundity, divergence in the methodological approaches used to evaluate this association have prevented firm conclusions being reached.

STUDY DESIGN, SIZE, DURATION

The Maternal-Infant Research on Environmental Chemicals (MIREC) Study is a cohort study of 2,001 women recruited before 14 weeks of gestation in 10 cities across Canada between 2008 and 2011.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A questionnaire was administered and medical chart data and biospecimens were collected from participants. After excluding women who withdrew, those for whom data were incomplete, those whose pregnancies followed birth control failure, and accounting for male fertility, 1743 participants remained. TTP was defined as the number of months of unprotected intercourse needed to become pregnant in the current pregnancy, as self-reported in the first trimester of pregnancy. Plasma concentrations of PFOA, PFOS and PFHxS measured in the first trimester were considered as a surrogate of preconception exposure. Fecundability odds ratios (FORs) were estimated using Cox proportional hazard models for discrete time. FOR < 1 denote a longer TTP and FORs >1 denote a shorter TTP. The odds of infertility (TTP > 12 months or infertility treatment in the index pregnancy) were estimated using logistic regression. Each chemical concentration (ng/ml) was log-transformed and divided by its SD.

MAIN RESULTS AND THE ROLE OF CHANCE

The cumulative probabilities of pregnancy at 1, 6 and 12 months were 0.42 (95% confidence interval (CI) 0.40-0.45), 0.81 (95% CI 0.79-0.83) and 0.90 (95% CI 0.89-0.92), respectively. The mean maternal age was 32.8 (SD 5.0) years. The geometric means (ng/ml) of PFOA, PFOS and PFHxS were 1.66 (95% CI 1.61-1.71), 4.59 (95% CI 4.46-4.72) and 1.01 (95% CI 0.97-1.05), respectively. After adjustment for potential confounders, PFOA and PFHxS were associated with a 11 and 9% reduction in fecundability per one SD increase (FOR = 0.89; 95% CI 0.83-0.94; P < 0.001 for PFOA and FOR = 0.91; 95% CI 0.86-0.97; P = 0.002 for PFHxS), while no significant association was observed for PFOS (FOR = 0.96; 95% CI 0.91-1.02; P = 0.17). In addition, the odds of infertility increased by 31% per one SD increase of PFOA (odds ratio (OR) = 1.31; 95% CI 1.11-1.53; P = 0.001) and by 27% per one SD increase of PFHxS (OR = 1.27; 95% CI 1.09-1.48; P = 0.003), while no significant association was observed for PFOS (OR = 1.14; 95% CI 0.98-1.34; P = 0.09).

LIMITATIONS, REASONS FOR CAUTION

Women with the highest concentrations of PFCs might have been excluded from the study if there is a causal association with infertility. The MIREC study did not assess concentrations of PFCs in males, semen quality, menstrual cycle characteristics or intercourse frequency.

WIDER IMPLICATIONS OF THE FINDINGS

Our results add to the evidence that exposure to PFOA and PFHxS, even at lower levels than previously reported, may reduce fecundability.

STUDY FUNDING/COMPETING INTERESTS

The MIREC study is supported by the Chemicals Management Plan of Health Canada, the Canadian Institutes for Health Research (CIHR, grant no. MOP - 81285) and the Ontario Ministry of the Environment. M.P.V. was supported by a CIHR Fellowship Award, and a CIHR-Quebec Training Network in Perinatal Research (QTNPR) Ph.D. scholarship. W.D.F. is supported by a CIHR Canada Research Chair. There are no conflicts of interest to declare.

Female fetus is associated with greater maternal insulin resistance in pregnancy

AIM

To explore the hypothesis that female fetus is associated with greater maternal insulin resistance during pregnancy.

METHODS

In a singleton pregnancy cohort study (n = 299), we compared maternal insulin resistance according to fetal sex, based on plasma biomarkers from a 50-g 1-h oral glucose tolerance test at 24-28 weeks gestation. The primary outcome was plasma glucose-to-insulin ratio. Other outcomes included plasma proinsulin-to-insulin ratio, and insulin, proinsulin, leptin, adiponectin and insulin-like growth factor I and II concentrations.

RESULTS

After adjusting for maternal race, age, parity, education, pre-pregnancy BMI, smoking and alcohol use, history of gestational diabetes, and gestational age at blood sampling, plasma insulin concentrations were significantly higher (mean ± sd: 66.4 ± 50.5 vs. 51.0 ± 46.1 mU/l; adjusted P = 0.001), and glucose-to-insulin ratios significantly lower (2.60 ± 2.03 vs. 3.77 ± 4.98 mg/dl/mU/l; adjusted P = 0.002) in women bearing a female vs those bearing a male fetus, despite similar glucose levels (116.4 ± 27.2 vs. 117.0 ± 31.9 mg/dl; adjusted P = 0.92).There were no significant differences in proinsulin-to-insulin ratios, or leptin, adiponectin, insulin-like growth factor I and insulin-like growth factor II concentrations by fetal sex.

CONCLUSION

Female fetus may be associated with greater maternal insulin resistance during pregnancy.

Maternal 25-hydroxyvitamin D and its association with childhood atopic outcomes and lung function

Background

It has been suggested that maternal vitamin D status in pregnancy influences the risk of asthma and atopy in the offspring. The epidemiological evidence to support these claims is conflicting and may reflect chance findings and differences in how vitamin D was assessed.

Objective

To examine the association between blood total maternal 25-hydroxy vitamin D (25(OH)D) concentrations in pregnancy and offspring asthma, atopy and lung function in the largest birth cohort study to date.

Methods

Participants were largely of white European origin and resident in the South West of England. We examined the associations of maternal 25(OH)D concentrations in pregnancy with the following outcomes in the offspring: wheeze, asthma, atopy, eczema, hayfever, at mean age 7.5 years (n = 3652–4696 depending on outcome), IgE at 7 years (n = 2915) and lung function and bronchial responsiveness at mean age 8.7 years (n = 3728–3784).

Results

Sixty-eight per cent of mothers had sufficient (> 50 nmol/L) concentrations of 25(OH)D, 27% were insufficient (27.5–49.99 nmol/L) and 5% were deficient (< 27.5 nmol/L). There was no evidence to suggest that maternal 25(OH)D concentration in pregnancy was associated with any respiratory or atopic outcome in the offspring. These findings remained after adjustment for season of measurement and for potential confounders. There was also no evidence that these relationships followed a non-linear form and no evidence that either deficient or high concentrations of maternal 25(OH)D were associated with atopic or respiratory outcomes.

Conclusions

We found no evidence that maternal blood 25(OH)D concentration in pregnancy is associated with childhood atopic or respiratory outcomes.

Lifelong training preserves some redox-regulated adaptive responses after an acute exercise stimulus in aged human skeletal muscle

Several redox-regulated responses to an acute exercise bout fail in aged animal skeletal muscle, including the ability to upregulate the expression of antioxidant defense enzymes and heat shock proteins (HSPs). These findings are generally derived from studies on sedentary rodent models and thus may be related to reduced physical activity and/or intraspecies differences as opposed to aging per se. This study, therefore, aimed to determine the influence of age and training status on the expression of HSPs, antioxidant enzymes, and NO synthase isoenzymes in quiescent and exercised human skeletal muscle. Muscle biopsy samples were obtained from the vastus lateralis before and 3 days after an acute high-intensity-interval exercise bout in young trained, young untrained, old trained, and old untrained subjects. Levels of HSP72, PRX5, and eNOS were significantly higher in quiescent muscle of older compared with younger subjects, irrespective of training status. 3-NT levels were elevated in muscles of the old untrained but not the old trained state, suggesting that lifelong training may reduce age-related macromolecule damage. SOD1, CAT, and HSP27 levels were not significantly different between groups. HSP27 content was upregulated in all groups studied postexercise. HSP72 content was upregulated to a greater extent in muscle of trained compared with untrained subjects postexercise, irrespective of age. In contrast to every other group, old untrained subjects failed to upregulate CAT postexercise. Aging was associated with a failure to upregulate SOD2 and a downregulation of PRX5 in muscle postexercise, irrespective of training status. In conclusion, lifelong training is unable to fully prevent the progression toward a more stressed muscular state as evidenced by increased HSP72, PRX5, and eNOS protein levels in quiescent muscle. Moreover, lifelong training preserves some (e.g., CAT) but not all (e.g., SOD2, HSP72, PRX5) of the adaptive redox-regulated responses after an acute exercise bout. Collectively, these data support many but not all of the findings from previous animal studies and suggest parallel aging effects in humans and mice at rest and after exercise that are not modulated by training status in human skeletal muscle.

A parallel group double-blind RCT of vitamin D3 assessing physical function: is the biochemical response to treatment affected by overweight and obesity?

Vitamin D may affect skeletal muscle function. In a double-blind, randomised, placebo-controlled trial, we found that vitamin D3 supplementation (400 or 1,000 I.U. vs. placebo daily for 1 year with bimonthly study visits) does not improve grip strength or reduce falls.

INTRODUCTION

This study aimed to test the supplementation effects of vitamin D3 on physical function and examine associations between overweight/obesity and the biochemical response to treatment.

METHODS

In a parallel group double-blind RCT, healthy postmenopausal women from North East Scotland (latitude-57° N) aged 60-70 years (body mass index (BMI), 18-45 kg/m(2)) were assigned (computer randomisation) to daily vitamin D3 (400 I.U. (n = 102)/1,000 I.U. (n = 101)) or matching placebo (n = 102) (97, 96 and 100 participants analysed for outcomes, respectively) from identical coded containers for 1 year. Grip strength (primary outcome), falls, diet, physical activity and ultraviolet B radiation exposure were measured bimonthly, as were serum 25(OH)D, adjusted calcium (ACa) and phosphate. Fat/lean mass (dual energy X-ray absorptiometry), anthropometry, 1,25-dihydroxyvitamin D and parathyroid hormone were measured at baseline and 12 months. Participants and researchers were blinded throughout intervention and analysis.

RESULTS

Treatment had no effect on grip strength (mean change (SD)/year = -0.5 (2.5), -0.9 (2.7) and -0.4 (3.3) kg force for 400/1,000 I.U. vitamin D3 and placebo groups, respectively (P = .10, ANOVA)) or falls (P = .65, chi-squared test). Biochemical responses were similar across BMI categories (<25.25-29.99, ≥30 kg/m(2)) with the exception of a small change at 12-months in serum ACa in overweight compared to non-overweight participants (P = .01, ANOVA; 1,000 I.U. group). In the placebo group, 25(OH)D peak concentration change (winter to summer) was negatively associated with weight (r = -.268), BMI (r = -.198), total (r = -.278) and trunk fat mass (r = -.251), with total and trunk fat mass predictive of winter to summer 25(OH)D change (P = .01/.004 respectively, linear regression).

CONCLUSION

We found no evidence of an improvement in physical function following vitamin D3 supplementation for 1 year.

Distinct relationships of intramuscular and subcutaneous fat with cortical bone: findings from a cross-sectional study of young adult males and females

CONTEXT

Intracellular fat within muscle and visceral tissue has been suggested to adversely influence bone development.

OBJECTIVE

The aim of the study was to evaluate associations between im fat, as reflected by muscle density as measured by peripheral quantitative computed tomography, and cortical bone parameters in young adults.

DESIGN/SETTING/PARTICIPANTS

We conducted a cross-sectional analysis of 1703 males and 2243 females aged 17.8 years from the Avon Longitudinal Study of Parents and Children.

OUTCOME MEASURES

We measured cortical bone parameters from midtibial peripheral quantitative computed tomography scans.

RESULTS

Muscle density (inversely related to im fat) was inversely associated with periosteal circumference (PC) (beta = -0.07 [95% confidence interval (CI), -0.1, -0.04]), cortical bone mineral density (BMDC) (beta = -0.21 [95% CI, -0.26, -0.17]), and cortical thickness (CT) (beta = -0.37 [95% CI, -0.42, -0.33]) (males and females combined, adjusted for age, height, gender, and muscle cross-sectional area). In contrast, sc fat area was positively associated with PC (beta = 0.10 [95% CI, 0.07, 0.12]), but no association was seen with BMDC or CT. To examine the role of candidate intermediary metabolic pathways, analyses were repeated after adjustment for insulin, C-reactive protein, and β-C-telopeptides of type I collagen. Whereas similar associations were observed after adjustment for insulin and C-reactive protein, the association between muscle density and BMDC was partially attenuated by adjustment for β-C-telopeptides of type I collagen (beta = -0.14 [95% CI, -0.20, -0.08]).

CONCLUSION

Although im and sc fat were both positively associated with cortical bone mass, the nature of these relationships differed in that im fat was predominantly associated with CT and BMDC, whereas sc fat was mainly associated with PC. These relationships were largely independent of candidate metabolic pathways, such as altered bone resorption, insulin resistance, or inflammation.

Effect of a 300 000-IU loading dose of ergocalciferol (Vitamin D2) on circulating 1,25(OH)2-vitamin D and fibroblast growth factor-23 (FGF-23) in vitamin D insufficiency

CONTEXT

Several trials have reported an increased risk of fractures and falls after intermittent high-dose vitamin D. Treatment with loading doses of vitamin D may increase 1,25(OH)(2) vitamin D catabolism through changes in calcium/phosphate homeostasis and fibroblast growth factor-23 (FGF-23).

OBJECTIVE

The aim was to determine the effects of high-dose vitamin D on circulating concentrations of 1,25(OH)(2) vitamin D and FGF-23 in patients with osteoporosis and vitamin D insufficiency.

DESIGN, SETTING, PATIENTS, AND INTERVENTION

We carried out a prospective study of 45 subjects with vitamin D deficiency/insufficiency treated with a bolus dose of 300 000 IU of vitamin D(2) im. Blood samples were obtained at baseline and 1, 2, and 3 months after treatment.

OUTCOME MEASURES

Changes in 1,25(OH)(2)-vitamin D and FGF-23 were measured.

RESULTS

Loading dose of vitamin D(2) increased 1,25(OH)(2)-vitamin D(2) at 3 months, with a mean [SD] of 41 [56] pmol/L at baseline and 162.3 [137.8] pmol/L at 3 months (P < .001). FGF-23 increased significantly at all time points with a peak at 3 months, with percent change from baseline (mean [SEM]) of 50% [48%] at 3 months (P < .01). There was a positive correlation between FGF-23 and serum phosphate (r = 0.36, P = .024) and calcium (r = 0.532, P < .001) and a negative correlation between total 1,25(OH)(2)-vitamin D and FGF-23 (r = -0.32, P = .036) at 3 months.

CONCLUSIONS

High-dose vitamin D increases 1,25(OH)(2)-vitamin D and FGF-23 concentration. Further studies are required to determine whether adjusting vitamin D dose and frequency to minimize increases in FGF-23 may prevent the adverse outcomes associated with high-dose intermittent vitamin D supplementation.

Markers of bone health, renal function, liver function, anthropometry and perception of mood: a comparison between Flat and National Hunt Jockeys

Given the requirement of professional jockeys to make-weight daily, we tested the hypothesis that Flat and National Hunt (Jump) jockeys would display compromised health markers (bone health, vitamin D, liver and kidney function and mood) compared with established clinical norms, with Flat jockeys affected the greater. Daily energy intake was lower in Flat compared with Jump jockeys (6.11±1.25 vs. 7.47±0.83 MJ.day - 1, P=0.01) whereas there was no difference in urine osmolality (811±198 vs. 678±317 mOsmol x kg(-1) respectively, P=0.13). Serum total 25(OH)D was insufficient in Flat and Jump jockeys (37.6±28 vs. 35.1±14 nmol x L(-1) respectively although there was no difference between groups (P=0.79). Markers of bone metabolism (Plasma β-carboxy-terminal cross-linked teleopeptide (CTX) and Intact Parathyroid Hormone (PTH) and liver and kidney function were within clinical normative ranges although CTX and PTH were higher than average. Abnormal mood profiles were observed in both groups although significantly poorer in the Flat jockeys (P=0.01). We conclude that the current practices of jockeys to make-weight may have detrimental effects upon their health with Flat jockeys affected more so than Jump jockeys. Future studies should investigate the effects of improved dietary practices on the mental and physical health of Flat and Jump jockeys.

Assessment of vitamin D concentration in non-supplemented professional athletes and healthy adults during the winter months in the UK: implications for skeletal muscle function

The current study implemented a two-part design to (1) assess the vitamin D concentration of a large cohort of non-vitamin D supplemented UK-based athletes and 30 age-matched healthy non-athletes and (2) to examine the effects of 5000 IU · day(-1) vitamin D(3) supplementation for 8-weeks on musculoskeletal performance in a placebo controlled trial. Vitamin D concentration was determined as severely deficient if serum 25(OH)D < 12.5 nmol · l(-1), deficient 12.5-30 nmol · l(-1) and inadequate 30-50 nmol · l(-1). We demonstrate that 62% of the athletes (38/61) and 73% of the controls (22/30) exhibited serum total 25(OH)D < 50 nmol · l(-1). Additionally, vitamin D supplementation increased serum total 25(OH)D from baseline (mean ± SD = 29 ± 25 to 103 ± 25 nmol · l(-1), P = 0.0028), whereas the placebo showed no significant change (53 ± 29 to 74 ± 24 nmol · l(-1), P = 0.12). There was a significant increase in 10 m sprint times (P = 0.008) and vertical-jump (P = 0.008) in the vitamin D group whereas the placebo showed no change (P = 0.587 and P = 0.204 respectively). The current data supports previous findings that athletes living at Northerly latitudes (UK = 53° N) exhibit inadequate vitamin D concentrations (<50 nmol · l(-1)). Additionally the data suggests that inadequate vitamin D concentration is detrimental to musculoskeletal performance in athletes. Future studies using larger athletic groups are now warranted.

Circulating sclerostin and Dickkopf-1 (DKK1) in predialysis chronic kidney disease (CKD): relationship with bone density and arterial stiffness

Abnormalities of bone metabolism and increased vascular calcification are common in chronic kidney disease (CKD) and important causes of morbidity and mortality. The Wnt signaling pathway may play a role in the bone and vascular disturbances seen in CKD, termed collectively "CKD-MBD." The aim of the study was to investigate the possible association of circulating concentrations of the secreted Wnt signaling inhibitors DKK1 and sclerostin with BMD and arterial stiffness in predialysis CKD. Seventy-seven patients (48 M, 29 F), mean age 57 (SD = 14) years with CKD stages 3B (n = 32) and 4 (n = 45) were studied. Sclerostin, DKK1, PTH, and 1,25(OH)(2)D were analyzed. BMD was measured at the lumbar spine (LS), femoral neck (FN), total hip (TH), and forearm (FARM). Arterial stiffness index was determined by contour analysis of digital volume pulse (SI(DVP)). There was a positive correlation between sclerostin and age (r = 0.47, p < 0.000). Sclerostin was higher in men than women (p = 0.013). Following correction for age and gender, there was a negative association between GFR and sclerostin (p = 0.002). We observed a positive association between sclerostin and BMD at the LS (p = 0.0001), FN (p = 0.004), and TH (p = 0.002). In contrast, DKK1 was negatively associated with BMD at the FN (p = 0.038). A negative association was seen between DKK1 and SI(DVP) (p = 0.027). Our data suggest that the Wnt pathway may play a role in CKD-MBD. Prospective studies are required to establish the clinical relevance of sclerostin and DKK1 as serological markers in CKD.

Longitudinal vitamin D status in pregnancy and the risk of pre-eclampsia

OBJECTIVE

Whether vitamin D deficiency in pregnancy is a cause of pre-eclampsia remains controversial. Most previous studies to date have assessed exposure at only one time-point in pregnancy. We assessed longitudinal vitamin D status during pregnancy and the risk of pre-eclampsia.

DESIGN

Prospective cohort study.

SETTING

Seventeen urban obstetric hospitals, Canada.

POPULATION

Pregnant women who were participants in a trial of vitamin C and E supplementation for the prevention of pre-eclampsia. Canadian participants who consented to participate in a biobank with plasma specimens available at the baseline visit were included (n = 697).

METHODS

Maternal plasma 25-hydroxyvitamin D (25(OH)D) concentrations were measured at 12-18 and 24-26 weeks of gestation using chemiluminescence immunoassay.

MAIN OUTCOME MEASURES

Pre-eclampsia.

RESULTS

Of the women, 39% were vitamin D deficient (25(OH)D <50 nmol/l). A strong positive correlation was observed in maternal 25(OH)D concentrations between the two gestational age windows (r = 0.69, P < 0.0001). Mean maternal 25(OH)D concentrations at 24-26 weeks of gestation were significantly lower in women who subsequently developed pre-eclampsia compared with those who did not (mean ± SD: 48.9 ± 16.8 versus 57.0 ± 19.1 nmol/l, P = 0.03). Women with 25(OH)D < 50 nmol/l at 24-26 weeks gestation experienced an increased risk of pre-eclampsia (adjusted odds ratio 3.24, 95% confidence interval 1.37-7.69), whereas the association was not statistically significant for maternal 25(OH)D level at 12-18 weeks of gestation.

CONCLUSIONS

Lower maternal 25(OH)D levels at late mid-trimester were associated with an increased risk of pre-eclampsia.

Diabetes in pregnancy may differentially affect neonatal outcomes for twins and singletons

AIM

We tested the hypothesis that diabetes in pregnancy may differentially affect neonatal outcomes in twin vs. singleton pregnancies.

METHODS

In a retrospective cohort analysis of twins (n = 422 068) and singletons (n = 14 298 367) born in the USA from 1998 to 2001, we evaluated the adjusted odds ratios of adverse neonatal outcomes comparing diabetic vs. non-diabetic pregnancies, controlling for maternal characteristics. Primary outcomes include macrosomia (birthweight for gestational age > 90th percentile), congenital anomalies, low 5-min Apgar score (< 4) and neonatal death.

RESULTS

Diabetes in pregnancy was associated with a similarly increased risk of congenital anomalies (adjusted odds ratios 1.52 vs. 1.59) and smaller increased risks of preterm birth (adjusted odds ratios 1.27 vs. 1.49) and macrosomia (adjusted odds ratios 1.38 vs. 2.03) in twins vs. singletons, but reduced risks of low 5-min Apgar score (adjusted odds ratio 0.74) and neonatal death (adjusted odds ratio 0.76) in twins but not singletons.

CONCLUSIONS

Diabetes in pregnancy may differentially affect neonatal outcomes in twins and singletons, indicating a need for further studies to differentiate the effects by clinical subtypes of diabetes in pregnancy, and to consider/evaluate differential clinical management protocols of diabetes in multiple vs. singleton pregnancies.

Sunlight and dietary contributions to the seasonal vitamin D status of cohorts of healthy postmenopausal women living at northerly latitudes: a major cause for concern?

We assessed sunlight and dietary contributions to vitamin D status in British postmenopausal women. Our true longitudinal 25-hydroxyvitamin D (25(OH)D) measurements varied seasonally, being lower in the north compared to the south and lower in Asian women. Sunlight exposure in summer and spring provided 80% total annual intake of vitamin D.

INTRODUCTION

Vitamin D deficiency is highlighted as a potential problem for countries at high latitude, but there are few true longitudinal, seasonal data to allow regional comparisons. We aimed to directly compare seasonal variation in vitamin D status (25(OH)D) in postmenopausal women at two northerly latitudes and to assess the relative contributions of sunlight exposure and diet.

METHODS

Vitamin D status was assessed in 518 postmenopausal women (age 55-70 years) in a two-centre cohort study with serum collected at fixed three-monthly intervals from summer 2006 for immunoassay measurement of 25(OH)D and parathyroid hormone. At 57° N (Aberdeen, Scotland, UK), there were 338 Caucasian women; at 51° N (Surrey, South of England, UK), there were 144 Caucasian women and 35 Asian women. UVB exposure (polysulphone film badges) and dietary vitamin D intakes (food diaries) were also estimated.

RESULTS

Caucasian women had lower 25(OH)D (p < 0.001) at 57° N compared to 51° N. Median (interquartile range) in nanomoles per litre for summer (June-August) at 57° N was 43.0 (20.9) and at 51° N was 62.5 (26.6) and for winter (December-February) at 57° N was 28.3 (18.9) and at 51° N was 39.9 (24.0). For Asian women at 51° N, median 25(OH)D was 24.0 (15.8) nmol/L in summer and 16.9 (15.9) nmol/L in winter. Median dietary vitamin D intakes were 80-100 IU for Caucasians and 50-65 IU for the Asian women. Sunlight was the main contributor to 25(OH)D with spring and summer providing >80% total annual intake.

CONCLUSIONS

These longitudinal data show significant regional and ethnic differences in UVB exposure and vitamin D status for postmenopausal women at northerly latitudes. The numbers of women who are vitamin D deficient is a major concern and public health problem.

Identification of alkaptonuria in the general population: a United Kingdom experience describing the challenges, possible solutions and persistent barriers

Progress in research into rare diseases is challenging. This paper discusses strategies to identify individuals with the rare genetic disease alkaptonuria (AKU) within the general population. Strategies used included a questionnaire survey of general practitioners, a dedicated website and patient network contact, targeted family screening and medical conference targeting. Primary care physicians of the UK were targeted by a postal survey that involved mailing 11,151 UK GPs; the response rate was 18.2%. We have identified 75 patients in the UK with AKU by the following means: postal survey (23), targeted family screening (11), patient networks and the website (41). Targeting medical conferences (AKU, rare diseases, rheumatology, clinical biochemistry, orthopaedics, general practitioners) did not lead to new identification in the UK but helped identify overseas cases. We are now aware of 626 patients worldwide including newly identified non-UK people with AKU in the following areas: Slovakia (208), the rest of Europe (including Turkey) (79), North America (including USA and Canada) (110), and the rest of the world (154). A mechanism for identifying individuals with AKU in the general population-not just in the UK but worldwide-has been established. Knowledge of patients with AKU, both in the UK and outside, is often confined to establishing their location in a particular GP practice or association with a particular medical professional. Mere identification, however, does not always lead to full engagement for epidemiological research purposes or targeting treatment since further barriers exist.

A case-control study of nutritional factors associated with chronic suppurative otitis media in Yemeni children

BACKGROUND/OBJECTIVES

Undernutrition and chronic suppurative otitis media (CSOM) in children are common in low resource settings, but there are few studies of their interactions. The aim is to evaluate nutritional factors associated with CSOM in Yemeni children.

SUBJECTS/METHODS

A case-control study of 75 children with CSOM and 74 healthy controls. Assessment included dietary history, anthropometry, haemoglobin (Hb) and serum analytes zinc (Zn), copper (Cu), selenium (Se), iron, calcium, phosphate (PO(4)) and total 25-hydroxy vitamin D (25(OH)D).

RESULTS

Cases had lower mean Z-scores for weight-for-age, weight-for-height, body mass index and mid-upper arm circumference (MUAC) (all P<0.05), and lower mean concentrations of serum Zn (P=0.032), Se (P<0.001) and calcium adjusted for albumin (P=0.026). Age-adjusted Hb and iron biomarkers did not differ between cases and controls. There was high prevalence of low serum Zn concentration (≥ 90%) and vitamin D deficiency in both cases (80%) and controls (96%). Duration of ear discharge was negatively correlated with total 25(OH)D (P=0.028), calcium adjusted for albumin (P<0.001), PO(4) (P=0.002), transferrin receptor/log ferritin ratio (P<0.001) and Cu (P<0.001), and positively correlated with child age and MUAC (both P<0.001).

CONCLUSIONS

Children with CSOM were more undernourished than controls with lower mean serum Zn, Se and calcium concentrations. Vitamin D-deficient and iron-replete children had longer duration of infection, although this association was lost with age adjustment. Trials evaluating specific micronutrients are required in order to investigate specific nutrient-infection interactions in CSOM.

Effects of Atenolol, Labetalol and Methyldopa on Endogenous Antioxidants In-vitro

The aim of this study was to investigate whether atenolol, labetalol and methyldopa, which are commonly used for the treatment of hypertension in pregnancy, can induce antioxidant activity.

Reactive oxygen species scavengers (plasma thiol, red cell lysate thiol, red cell superoxide dismutase, red cell membrane thiol and plasma glutathione) were measured after incubation of peripheral blood with atenolol and methyldopa, respectively.

The results showed that atenolol and labetalol could significantly raise the levels of plasma thiol and membrane thiol but had no effects on lysate thiol, superoxide dismutase and glutathione. The effects on membrane thiol occurred after 60 min incubation and on plasma thiol after 120 min incubation.

The data also suggest that atenolol and labetalol at lower concentrations tend to have additive effects on reactive oxygen species scavengers but at higher concentrations do not.

Methyldopa had no significant effect on any of the parameters measured.

These findings suggest that atenolol and labetalol are able to induce higher levels of antioxidant activity.

Effect of oral phosphate and alendronate on bone mineral density when given as adjunctive therapy to growth hormone replacement in adult growth hormone deficiency

BACKGROUND

Adult GH deficiency (AGHD) is associated with osteoporosis, which occurs as the result of reduced sensitivity of the bone and kidney to the effect of PTH.

AIM

The aim of the study was to examine the effect of oral phosphate and alendronate therapy on PTH sensitivity, bone turnover, and bone mineral density (BMD) in AGHD patients.

METHODS

Forty-four AGHD patients were hospitalized for 24 h, and half-hourly blood and 3-hourly urine samples were collected for PTH, nephrogenous cAMP (marker of renal PTH activity), procollagen type-I amino-terminal propeptide, and type-I collagen β C-telopeptide. Patients were randomized to one of six groups: patients who were previously naive to GH were randomized to receive GH replacement (GHR) alone, GHR+alendronate, or GHR+phosphate-sandoz, whereas patients already receiving GHR were randomized to continue GHR alone, GHR+alendronate, or GHR+phosphate-sandoz. Study visits were repeated after 1, 3, 6, and 12 months in the previously GH-naive group and after 12 months in the previously GH-replaced group. BMD was measured at 0 and 12 months.

RESULTS

Patients receiving GHR+phosphate had greater increases in nephrogenous cAMP and bone markers than patients receiving GHR alone (P < 0.01), and this was associated with greater increases in BMD (P < 0.01). In the GHR+alendronate groups, type-I collagen β C-telopeptide decreased (P < 0.001), and BMD increases were greater than in those receiving GHR alone (P < 0.05). The greatest increases in BMD were seen in patients receiving GHR+phosphate.

CONCLUSIONS

Phosphate and alendronate therapy given in combination with GHR confer advantage in terms of BMD increase. Phosphate appears to exert its effect by increasing PTH target-organ action, whereas alendronate acts primarily through reduction in bone resorption.

Proceedings of the Rank Forum on Vitamin D

The Rank Forum on Vitamin D was held on 2nd and 3rd July 2009 at the University of Surrey, Guildford, UK. The workshop consisted of a series of scene-setting presentations to address the current issues and challenges concerning vitamin D and health, and included an open discussion focusing on the identification of the concentrations of serum 25-hydroxyvitamin D (25(OH)D) (a marker of vitamin D status) that may be regarded as optimal, and the implications this process may have in the setting of future dietary reference values for vitamin D in the UK. The Forum was in agreement with the fact that it is desirable for all of the population to have a serum 25(OH)D concentration above 25 nmol/l, but it discussed some uncertainty about the strength of evidence for the need to aim for substantially higher concentrations (25(OH)D concentrations>75 nmol/l). Any discussion of 'optimal' concentration of serum 25(OH)D needs to define 'optimal' with care since it is important to consider the normal distribution of requirements and the vitamin D needs for a wide range of outcomes. Current UK reference values concentrate on the requirements of particular subgroups of the population; this differs from the approaches used in other European countries where a wider range of age groups tend to be covered. With the re-emergence of rickets and the public health burden of low vitamin D status being already apparent, there is a need for urgent action from policy makers and risk managers. The Forum highlighted concerns regarding the failure of implementation of existing strategies in the UK for achieving current vitamin D recommendations.

Dietary patterns, bone resorption and bone mineral density in early post-menopausal Scottish women

BACKGROUND/OBJECTIVES

Several nutrients affect bone turnover. Dietary patterns may provide insights into which foods are important and how nutrition affects bone health. The aim of this study was to investigate the associations between dietary patterns, bone turnover and bone mineral density (BMD).

SUBJECTS/METHODS

This cross-sectional study examined 3236 Scottish women age 50-59 years, who were members of the Aberdeen Prospective Osteoporosis Screening Study. They had hip and spine BMD measurements (dual-energy X-ray absorptiometry) and provided samples for bone turnover markers. Diet was assessed by a validated food frequency questionnaire encompassing 98 foods, from which 35 food groups were systematically created. Dietary patterns were defined by principal components analysis. The bone measures were regressed onto the dietary pattern and adjusted for potential confounders.

RESULTS

Five dietary patterns were identified, three of which were associated with bone health. The 'healthy' pattern was associated with decreased bone resorption (r = 0.081, P < 0.001). Two other patterns (processed foods and snack food) were associated with lower BMD (femoral neck r = -0.056, r = -0.044, P < 0.001, respectively).

CONCLUSIONS

Dietary pattern may influence bone turnover and BMD. A healthy dietary pattern with high intakes of fruit and vegetables may lead to less bone resorption, and a poor dietary pattern rich in processed foods is associated with a decrease in BMD. This study confirms that a healthy diet is required for strong bones, and highlights that a nutrient-poor diet is a risk factor for osteoporosis.

Circulating fibroblast growth factor-23 increases following intermittent parathyroid hormone (1-34) in postmenopausal osteoporosis: association with biomarker of bone formation

Uncertainties exist regarding whether FGF-23 production is influenced by PTH and its involvement in bone formation. We evaluated FGF-23 response and its relation to changes in biomarkers of bone formation following intermittent PTH treatment. Twenty-seven women with a mean [SD] age of 75.8 [5.4] years with postmenopausal osteoporosis were treated with PTH(1-34) for 18 months. Bone mineral density (BMD) was measured at 6 and 18 months at the lumbar spine (LS) and total hip (TH). Blood samples were obtained at baseline, 1-3, 6-9, and 12-18 months. Serum calcium, phosphate, PTH, 25(OH)vitamin D, 1,25(OH)(2)vitamin D, markers of bone turnover, FGF-23, and sclerostin were measured. BMD increased at both the LS (11.6%, P < 0.001) and TH (2.5%, P < 0.01). The bone formation marker P1NP increased early (baseline mean [SD] 39.9 [24.4] μg/l, 1-3 months 88 [37.9] μg/l; P < 0.001) and remained higher than baseline throughout 18 months. FGF-23 also increased, with a peak response at 6-9 months (increase 65%, P = 0.002). Serum phosphate remained stable. A significant increase in 1.25(OH)(2)vitamin D (P = 0.02) was seen at 1-3 months only. A small but significant reduction in sclerostin was seen at 6-9 (P = 0.02) and 12-18 months (P = 0.06). There was a positive correlation between changes in P1NP and FGF-23 (6-9 months r = 0.78, P < 0.001). FGF-23 is increased by intermittent PTH(1-34). This is related to early changes in P1NP, suggesting that the skeletal effects of PTH may involve FGF-23. Further studies are required to elucidate this.

Fibroblast growth factor-23 is associated with C-reactive protein, serum phosphate and bone mineral density in chronic kidney disease

We investigated the association between fibroblast growth factor-23 (FGF-23) and (1) the biochemical parameters implicated in chronic kidney disorder (CKD)-bone and mineral disorder (CKD-MBD) and (2) bone mineral density (BMD) in patients with CKD 1-4. C-reactive protein (CRP) and serum phosphate correlated with FGF-23. A significant association was seen between FGF-23 and BMD at the hip.

INTRODUCTION

Circulating FGF-23 is elevated in CKD, although the primary stimulus remains unclear. Moreover, it is still unknown whether increase in FGF-23 has a biological effect on bone metabolism. The aim of the study was to investigate the association of FGF-23 with (1) the biochemical parameters linked with CKD-bone and mineral disorder (CKD-MBD) and (2) bone mineral density in CKD.

METHODS

We studied 145 patients (74 M, 71 F) aged (mean [SD]) 53 [14] years with CKD 1-4. Serum calcium, phosphate, parathyroid hormone, FGF-23, 25 (OH) vitamin D, 1, 25 (OH)(2) vitamin D, bone turnover markers, CRP were determined. BMD was measured at the lumbar spine, femoral neck (FN), forearm, and total hip (TH). Multivariate analysis was undertaken to explore the association between (1) the biochemical variables and FGF-23 and (2) FGF-23 and BMD.

RESULTS

Elevations in FGF-23 occurred in CKD stage 3 compared to CKD stage 1/2, although no significant differences in serum phosphate were observed. Serum phosphate (p<0.001), CRP (p<0.001) and diabetes mellitus (p<0.05) were associated with FGF-23. BMD Z-score was significantly lower at the TH and FN in CKD 4 (p<0.05). A significant association was seen between BMI, FGF-23, bone specific alkaline phosphatase and BMD at the TH (p<0.05).

CONCLUSIONS

The data suggest that FGF-23 may be associated with parameters implicated in the complications of CKD. Longitudinal studies are required for further clinical evaluation.

Seasonal 25-hydroxyvitamin D changes in British postmenopausal women at 57 degrees N and 51 degrees N: a longitudinal study

The UK has insufficient intensity of sunlight at wavelengths 290-315 nm to enable cutaneous synthesis of vitamin D from October to April. There are regional differences in UVB strength throughout the UK but whether this translates to differences in vitamin D status is not known. We have reported seasonal variations in a cross-sectional study of over 3000 Scottish women in Aberdeen. The aim of this longitudinal study was to compare the seasonal variation of serum 25-hydroxyvitamin D [25(OH)D] in postmenopausal women residing in Aberdeen (57 degrees N) and Surrey (51 degrees N). Women attended 3-monthly visits over 12 months, starting summer 2006. In Aberdeen, 338 Caucasian women (mean age+/-SD, 61.7+/-1.5 years); and at Surrey, 138 Caucasian women (61.4+/-4.5 years) and 35 Asian women (59.9+/-6.4 years) had serum 25(OH)D measured by IDS enzyme immunoassay. In winter/spring none of the Caucasian women living in Surrey had 25(OH)D<20 nmol/L, but nearly a quarter of women in Aberdeen were vitamin D-deficient. This number decreased to 4.2% in summer/autumn. For the Asian women 17.1% were vitamin D-deficient in summer, increasing to 58.1% in winter. Using higher 25(OH)D deficiency cut-offs, the percentage of women affected was much higher. These longitudinal data show clear differences in vitamin D status between the north and south of the UK, and marked ethnic differences. They are consistent with our previous data and with cross-sectional data from the 1958 birth cohort. The low vitamin D status may have implications for bone health and other health outcomes, which is currently being investigated in this publication group. The extent of vitamin D deficiency in Asian women residing in the South of England is of concern.

Correlation of serum-adjusted calcium with ionized calcium over a 24-h period in patients with adult growth hormone deficiency before and after growth hormone replacement

Background

Difficulties associated with measuring ionized calcium in clinical practice have led to the use of total calcium, with or without adjustment for albumin concentration, as an estimate of calcium metabolism. We examined the correlation between ionized and total/adjusted calcium over a 24-h period in patients with adult growth hormone deficiency (AGHD), a group of patients with previously reported alterations in calcium metabolism.

Methods

Four patients with AGHD were consented to the study. They were hospitalized for 24 h where half-hourly blood samples were collected for ionized calcium, total calcium, albumin and creatinine, before and one month after the commencement of growth hormone replacement. Total calcium concentration was adjusted for serum albumin.

Results

Strong correlations were found between ionized calcium and adjusted calcium ( r2 = 0.840 and 0.766 for visits 1 and 2, respectively, P < 0.001), and between ionized calcium and total calcium ( r2 = 0.828 and 0.731 for visits 1 and 2, respectively, P < 0.001). Correlations remained significant during the day (ionized versus adjusted calcium: r2 = 0.847 and 0.780 for visits 1 and 2, respectively; ionized versus total calcium: r2 = 0.860 and 0.792 for visits 1 and 2, respectively, all P < 0.001) and at night (ionized versus adjusted calcium: r2 = 0.831 and 0.802 for visits 1 and 2, respectively; ionized versus total calcium: r2 = 0.767 and 0.722 for visits 1 and 2, respectively, all P < 0.001).

Conclusion

The results of our study suggest that total calcium and serum-adjusted calcium can be used in place of ionized calcium as a reliable indicator of calcium metabolism over a 24-h period in patients with AGHD.

Use of risedronate to prevent bone loss following a single course of glucocorticoids: findings from a proof-of-concept study in inflammatory bowel disease

SUMMARY

We performed a randomised controlled trial (RCT) to determine whether risedronate 35 mg once weekly prevents bone loss following an 8-week reducing course of prednisolone given for an exacerbation of inflammatory bowel disease (IBD). The greatest change in bone mineral density (BMD) was at Ward's triangle (WT), which fell by 2.2% in the placebo group, compared with a reduction of 0.8% in the risedronate group.

INTRODUCTION

Whether bisphosphonates can prevent bone loss associated with intermittent glucocorticoid (GC) therapy is unknown, reflecting the difficulty in performing RCTs in this context.

METHOD

To explore the feasibility of RCTs to examine this question, lumbar spine (LS; L2-4) and hip dual X-ray absorptiometry (DXA) scans were performed in 78 patients commencing a GC therapy course for a relapse of IBD. They were then randomised to receive placebo or risedronate 35 mg weekly for 8 weeks, after which the DXA scan was repeated.

RESULTS

For LS BMD, there was no change in the placebo group (0.1 +/- 0.4, p = 0.9), but there was an increase after risedronate (0.8 +/- 0.4, p = 0.04; mean% +/- SEM by paired Student's t test). There were small decreases in both groups at the total hip (-0.5 +/- 0.3, p = 0.04; -0.5 +/- 0.3, p < 0.05, placebo and risedronate, respectively). At WT, BMD fell after placebo (-2.2 +/- 0.5, p = 0.001) but not risedronate (-0.8 +/- 0.5, p = 0.09; p = 0.05 for between-group comparison).

CONCLUSION

RCTs can be used to examine whether bisphosphonates prevent bone loss associated with intermittent GC therapy, providing metabolically active sites such as WT are employed as the primary outcome.

Oral calcium supplementation reverses the biochemical pattern of parathyroid hormone resistance in underprivileged Indian toddlers

BACKGROUND

Toddlers in Pune, India, accustomed to low dietary calcium intake but vitamin D replete have low serum ionised calcium and inappropriately raised serum inorganic phosphorus concentrations together with elevated serum parathyroid hormone (PTH) concentrations. We hypothesised that dietary calcium deficiency leads to end organ resistance to PTH, thus resulting in mild hypocalcaemia and hyperphosphataemia, and that this would be reversed by oral calcium supplementation.

METHODS

51 subjects (25 male; mean (SD) age 2.4 (0.8) years) from an urban slum in Pune were randomised to 500 mg of oral calcium supplement or placebo, daily, for 8 weeks. All subjects received 20 mg of oral elemental iron, daily, as 90% had a serum ferritin concentration <12 microg/l. All subjects were examined for clinical stigmata of rickets and had a wrist radiograph performed. Serum concentrations of ionised calcium, phosphorus, PTH and fibroblast growth factor-23 (FGF-23) were measured at the start and end of the trial.

RESULTS

No subject had clinical or radiological evidence of rickets. There was a significant increase in mean serum ionised calcium concentration (p<0.001) in the supplemented but not the placebo group (p = 0.32). The decrease in mean serum phosphorus concentration in the supplemented group was greater (p<0.001) than in the placebo group (p = 0.003). Mean serum PTH fell in the calcium supplemented (p = 0.001) but not in the placebo (p = 0.303) group. The mean serum FGF-23 concentration did not change in response to calcium supplementation.

CONCLUSIONS

From these data the authors conclude that low dietary calcium intake is associated with resistance to PTH.

Acidification and urine calcium: is it a preanalytical necessity?

Background

It has been suggested that for the accurate measurement of calcium in urine, samples must be collected into bottles containing acid. Acidification poses risks to both patients and laboratory staff. Here we reappraise whether acidification is a preanalytical necessity.

Methods

Twenty-four-hour urine samples were collected from 133 patients into bottles without acid or preservatives. In a subset of 29 patients, 10 mL aliquots were prepared to test the effect on urine calcium of 0.1, 1.0 and 5.0 mol/L hydrochloric acid (HCl). Calcium was then measured immediately after acidification, after 12 h and seven days storage at 4°C. In a separate study, urine calcium concentrations in paired control (non-acidified) and acidified (with 5 mol/L HCl) samples were compared in 133 patients. When available, we recorded the time from start of urine collection to time of analysis. Calcium was measured using the cresolphthalein complexone colorimetric endpoint assay on the Roche Modular system.

Results

There was no significant difference in the calcium concentration in the 29 cases studied between the varying acid concentrations tested compared with non-acidified urine ( P = 0.987). Overall, in 133 patients there was no difference between control and acidified samples ( P = 0.888). We found no correlation between basal urine pH and urine calcium at all time points studied.

Conclusions

Our results suggest that the acidification of urine samples is not a preanalytical necessity for the measurement of urine calcium.

Nutritional factors in the pathogenesis of ear disease in children: a systematic review

BACKGROUND

Ear disease is a major health problem in poorly resourced countries. The role of nutritional deficiencies in its pathogenesis and in relation to chronic suppurative otitis media (CSOM) has not been reviewed previously.

METHODS

A systematic review was undertaken using Pubmed, SCOPUS, Cinahl on Ovid, the Cochrane Database and selected medical journals, with no language restriction. Nutritional mechanisms potentially related to ear disease and CSOM risks were reviewed. All studies (observational, case-control, cohort and clinical trials including randomised controlled trials) with nutrition-related information were included. The titles and/or abstracts of all retrieved studies were reviewed and full articles were obtained for relevant studies. Exclusion criteria were multiple publication or studies which did not report nutritional information.

RESULTS

Supplementation studies using single micronutrients and vitamins to determine efficacy in reducing acute or chronic otitis media provided some evidence for an association of middle-ear pathology with deficiencies of zinc or vitamin A. Multi-micronutrient supplementation studies provided further support for a beneficial effect, although the number of studies was small and they were heterogeneous and uncontrolled. No human study was identified which specifically examined the association between copper, selenium or vitamin D status and middle-ear disease or infection.

CONCLUSION

Particularly in developing countries, research on micronutrient status and vitamin deficiency and their influence on middle-ear disease is required to improve knowledge of the pathogenesis of middle-ear infection and to determine the relevance of nutritional interventions in prevention and treatment.

Primary birthing attendants and birth outcomes in remote Inuit communities--a natural "experiment" in Nunavik, Canada

BACKGROUND

There is a lack of data on the safety of midwife-led maternity care in remote or indigenous communities. In a de facto natural "experiment", birth outcomes were assessed by primary birthing attendant in two sets of remote Inuit communities.

METHODS

A geocoding-based retrospective birth cohort study in 14 Inuit communities of Nunavik, Canada, 1989-2000: primary birth attendants were Inuit midwives in the Hudson Bay (1529 Inuit births) vs western physicians in Ungava Bay communities (1197 Inuit births). The primary outcome was perinatal death. Secondary outcomes included stillbirth, neonatal death, post-neonatal death, preterm, small-for-gestational-age and low birthweight birth. Multilevel logistic regression was used to obtain the adjusted odds ratios (aOR) controlling for maternal age, marital status, parity, education, infant sex and plurality, community size and community-level random effects.

RESULTS

The aORs (95% confidence interval) for perinatal death comparing the Hudson Bay vs Ungava Bay communities were 1.29 (0.63 to 2.64) for all Inuit births and 1.13 (0.48 to 2.47) for Inuit births at > or =28 weeks of gestation. There were no statistically significant differences in the crude or adjusted risks of any of the outcomes examined.

CONCLUSION

Risks of perinatal death were somewhat but not significantly higher in the Hudson Bay communities with midwife-led maternity care compared with the Ungava Bay communities with physician-led maternity care. These findings are inconclusive, although the results excluding extremely preterm births are more reassuring concerning the safety of midwife-led maternity care in remote indigenous communities.

Sex steroids and bone turnover markers in men with symptomatic vertebral fractures

Sex steroids play an important role in the maintenance of bone density in men and women, but the circulating, biologically active unbound fraction is influenced by the concentration of sex hormone binding globulin (SHBG). SHBG increases with advancing age in men and leads to a reduction in serum free testosterone and oestradiol, which may then affect bone turnover, bone mineral density (BMD) and the risk of fractures. We have therefore measured total and unbound sex steroids, SHBG, bone turnover markers and BMD in 57 men with symptomatic low trauma vertebral fractures and 57 age-matched male control subjects. Fasting blood and urine samples were collected from all subjects, who also underwent BMD measurement of the lumbar spine and hip. Serum testosterone, oestradiol, SHBG, bone specific alkaline phosphatase (bone ALP) and urine free deoxypyridinoline/creatinine ratio (fDPD/Cr) were measured. Free sex steroid concentrations were calculated using their ratio with SHBG and albumin and bioavailable testosterone was measured using radioimmunoassay. The two groups were then compared and regression models developed to determine the best predictors of BMD and fracture. Men with vertebral fractures had significantly lower weight and BMD at all sites than control subjects (p<0.0001). Serum total testosterone and oestradiol did not differ between the two groups, but calculated free androgen and free oestradiol indices were lower in the fracture group than the control subjects (p=0.04), due to higher SHBG (46.6 versus 36.1 nmol/L: p=0.005). The men with vertebral fractures had significantly higher mean bone ALP (15.8 versus 11.8 microg/L: p=0.002) and fDPD/Cr (5.5 versus 4.0 nmol/mmol: p=0.03). Stepwise multiple regression analysis in both fracture and control groups found body weight to be the best predictor of BMD. In the fracture group weight predicted between 19.7 and 30.7% of the variance in BMD and in control subjects this was between 12.3 and 13.2%. SHBG contributed to the model for hip BMD in the fracture group alone, so that weight and SHBG together accounted for 32 to 42.9% of the variance. A model combining BMD at the spine, total femur and femoral neck with height loss best predicted fracture. In conclusion, men with symptomatic vertebral fractures have higher SHBG and lower calculated free sex steroid indices, increased bone turnover and lower BMD. Whilst body weight was the best predictor of BMD, symptomatic vertebral fracture was best predicted by BMD and height loss.