The effect of prepubertal calcium carbonate supplementation on skeletal development in Gambian boys-a 12-year follow-up study

Perinatal HIV infection is associated with deficits in muscle function in children and adolescents in Zimbabwe

OBJECTIVES

To determine how muscle strength, power, mass, and density (i.e. quality) differ between children living with HIV (CWH) and those uninfected, and whether antiretroviral therapy (ART) regime is associated with muscle quality.

DESIGN

A cross-sectional study in Harare, Zimbabwe.

METHODS

The study recruited CWH aged 8-16 years, taking ART for at least 2 years, from HIV clinics, and HIV-uninfected children from local schools. Muscle outcomes comprised grip strength measured by hand-held Jamar dynamometer, lower limb power measured by standing long-jump distance, lean mass measured by dual-energy X-ray absorptiometry, and muscle density (reflecting intramuscular fat) by peripheral quantitative computed tomography. Linear regression calculated adjusted mean differences (aMD) by HIV status.

RESULTS

Overall, 303 CWH and 306 without HIV, had mean (SD) age 12.5 (2.5) years, BMI 17.5 (2.8), with 50% girls. Height and fat mass were lower in CWH, mean differences (SE) 7.4 (1.1) cm and 2.7 (0.4)kgs, respectively. Male CWH had lower grip strength [aMD 2.5 (1.1-3.9) kg, P  < 0.001], long-jump distance [7.1 (1.8-12.5) cm, P  = 0.006], muscle density [0.58 (0.12-1.05) mg/cm 3 , P  = 0.018, but not lean mass 0.06 (-1.08 to 1.21) kg, P  = 0.891) versus boys without HIV; differences were consistent but smaller in girls. Mediation analysis suggested the negative effect of HIV on jumping power in boys was partially mediated by muscle density ( P  = 0.032). CWH taking tenofovir disoproxil fumarate (TDF) had lower muscle density [0.56 (0.00-1.13)mg/cm 3 , P  = 0.049] independent of fat mass, than CWH on other ART.

CONCLUSION

Perinatally acquired HIV is associated, particularly in male individuals, with reduced upper and lower limb muscle function, not mass. Intra-muscular fat (poorer muscle quality) partially explained reductions in lower limb function. TDF is a novel risk factor for impaired muscle quality.

The effect of calcium supplementation in people under 35 years old: A systematic review and meta-analysis of randomized controlled trials

Background:

The effect of calcium supplementation on bone mineral accretion in people under 35 years old is inconclusive. To comprehensively summarize the evidence for the effect of calcium supplementation on bone mineral accretion in young populations (≤35 years).

Methods:

This is a systematic review and meta-analysis. The Pubmed, Embase, ProQuest, CENTRAL, WHO Global Index Medicus, Clinical Trials.gov, WHO ICTRP, China National Knowledge Infrastructure (CNKI), and Wanfang Data databases were systematically searched from database inception to April 25, 2021. Randomized clinical trials assessing the effects of calcium supplementation on bone mineral density (BMD) or bone mineral content (BMC) in people under 35 years old.

Results:

This systematic review and meta-analysis identified 43 studies involving 7,382 subjects. Moderate certainty of evidence showed that calcium supplementation was associated with the accretion of BMD and BMC, especially on femoral neck (standardized mean difference [SMD] 0.627, 95% confidence interval [CI] 0.338–0.915; SMD 0.364, 95% CI 0.134–0.595; respectively) and total body (SMD 0.330, 95% CI 0.163–0.496; SMD 0.149, 95% CI 0.006–0.291), also with a slight improvement effect on lumbar spine BMC (SMD 0.163, 95% CI 0.008–0.317), no effects on total hip BMD and BMC and lumbar spine BMD were observed. Very interestingly, subgroup analyses suggested that the improvement of bone at femoral neck was more pronounced in the peripeak bone mass (PBM) population (20–35 years) than the pre-PBM population (<20 years).

Conclusions:

Our findings provided novel insights and evidence in calcium supplementation, which showed that calcium supplementation significantly improves bone mass, implying that preventive calcium supplementation before or around achieving PBM may be a shift in the window of intervention for osteoporosis.

Funding:

This work was supported by Wenzhou Medical University grant [89219029].

Osteoporosis and bone fractures are common problems among older people, particularly older women. These conditions cause disability and reduce quality of life. Progressive loss of bone mineral density is usually the culprit. So far, strategies to prevent bone weakening with age have produced disappointing results. For example, taking calcium supplements in later life only slightly reduces the risk of osteoporosis or fracture. New approaches are needed.

Bone mass increases gradually early in life and peaks and plateaus around 20-35 years of age. After that period, bone mass slowly declines. Some scientists suspect that increasing calcium intake during this period of peak bone mass may reduce osteoporosis or fracture risk later in life.

A meta-analysis by Liu, Le et al. shows that boosting calcium intake in young adulthood strengthens bones. The researchers analyzed data from 43 randomized controlled trials that enrolled 7,382 participants. About half the studies looked at the effects of taking calcium supplements and the other half analyzed the effects of a high calcium diet. Boosting calcium intake in people younger than age 35 improved bone mineral density throughout the body. It also increased bone mineral density at the femoral neck, where most hip fractures occur. Calcium supplementation produced larger effects in individuals between the ages of 20 and 35 than in people younger than 20.

Both high calcium diets and calcium supplements with doses less than 1000 mg/d boosted bone strength. Higher dose calcium supplements did not provide any extra benefits. The analysis suggests people should pay more attention to bone health during early adulthood. Large randomized clinical trials are needed to confirm the long-term benefits of boosting calcium intake during early adulthood. But if the results are validated, taking calcium supplements, or eating more calcium-rich foods between the ages of 20 and 35 may help individuals build healthier bones and prevent fractures and osteoporosis later in life.

Nutrition in adolescent growth and development

During adolescence, growth and development are transformative and have profound consequences on an individual's health in later life, as well as the health of any potential children. The current generation of adolescents is growing up at a time of unprecedented change in food environments, whereby nutritional problems of micronutrient deficiency and food insecurity persist, and overweight and obesity are burgeoning. In a context of pervasive policy neglect, research on nutrition during adolescence specifically has been underinvested, compared with such research in other age groups, which has inhibited the development of adolescent-responsive nutritional policies. One consequence has been the absence of an integrated perspective on adolescent growth and development, and the role that nutrition plays. Through late childhood and early adolescence, nutrition has a formative role in the timing and pattern of puberty, with consequences for adult height, muscle, and fat mass accrual, as well as risk of non-communicable diseases in later life. Nutritional effects in adolescent development extend beyond musculoskeletal growth, to cardiorespiratory fitness, neurodevelopment, and immunity. High rates of early adolescent pregnancy in many countries continue to jeopardise the growth and nutrition of female adolescents, with consequences that extend to the next generation. Adolescence is a nutrition-sensitive phase for growth, in which the benefits of good nutrition extend to many other physiological systems.

Perspectives on the systematic review for the 2020 Dietary Reference Intakes for Koreans for calcium

An accurate assessment of the recommended calcium (Ca) intake may contribute to reducing the risk of fractures and chronic diseases, ultimately improving quality of life. This review was performed to summarize key findings of Ca studies, investigate the effect of Ca intake on health outcomes, and determine the adequacy of evidence to revise the 2015 Dietary Reference Intakes for Koreans (KDRIs) for Ca in 2020. Databases were searched for intervention studies that assessed health outcomes by providing Ca in diets or as supplements. The framework of the systematic review comprised conducting literature searches, data extraction, quality assessment of the literature, and summarizing key findings relevant to set the Estimated Average Requirement (EAR) and Tolerable Upper Intake Level (UL) for Ca for the 2020 KDRI. The final search was performed in June 2019. A total of 13,309 studies were identified through databases and manual search. Sixtyfive studies were included in the final quality assessment and were summarized according to health indicators. As bone health was used as an indicator of the EAR for Ca, literature reports on bone health were further categorized by the life-cycle stage of the participants. This systematic review did not find new evidence that could be applied to the general Korean adult population, including postmenopausal women, for defining a new EAR for Ca in the 2020 KDRIs. Evidence in most of the reviewed literature was considered weak; however, some evidence was found that could improve the criteria on how the EAR for Ca was determined in children and adolescents. A review of the literature for the 2020 KDRIs for Ca did not find strong evidence in order to change the recommended values of the 2015 KDRIs. More clinical interventions are required among Koreans to strengthen the body of evidence to warrant the revision of the KDRIs.

Tenth year reenrollment randomized trial investigating the effects of childhood probiotics and calcium supplementation on height and weight at adolescence

Microbiota and its modification with specific probiotics in early life could provide long term health benefits. Probiotics and calcium strengthen intestinal integrity and may support linear growth. This study investigated the long-term effects of childhood probiotics and calcium supplementation on growth in adolescence. We re-enrolled 238 adolescents aged 11-18 years from 494 children 10-years after 6-months of supplementation with either low-lactose milk fortified with low levels of calcium (LC, ∼50 mg/day, n = 53/124), with regular levels of calcium (RC, ∼440 mg/day, n = 70/126), or with regular calcium + 5 x 108 CFU/day Lactobacillus reuteri DSM 17938 (Reuteri, n = 55/124), or regular calcium + 5 x 108 CFU/day L. casei CRL 431 (Casei, n = 60/120). Changes in height-for-age z-score (HAZ) and body mass index-for-age z-score (BMIZ) were determined from the end of intervention to re-enrollment. General linear models were used to assess the effects on HAZ and BMIZ of group, gender, living area, maternal education, family income, physical activity, diet quality, nutritional status, and gut integrity as determined by urinary lactulose/mannitol ratio (L:M). Adolescent mean age was 15.3 years, mean HAZ was - 1.11, mean BMIZ was - 0.2 and median L:M (n = 155) was 0.23. Changes in HAZ and BMIZ were not significantly different between Casei, Reuteri, LC compared to RC. However, a significant decrease in BMIZ was observed among female adolescents in the Casei compared to RC group (- 0.5 SD, 95% CI - 0.8 to - 0.003, p = 0.048). Childhood probiotic and calcium supplementation may therefore selectively affect female adolescents.Clinical trial registration: This follow-up study has been registered at www.clinicaltrials.gov , Registry name: Rina Agustina, Registration number: NCT04046289, First Registration Date 06/08/19. web link: https://www.clinicaltrials.gov/ct2/show/NCT04046289 .

Hard facts and misfits: essential ingredients of public health nutrition research

Policy decisions and the practice of public health nutrition need to be based on solid evidence, developed through rigorous research studies where objective measures are used and results that run counter to dogma are not dismissed but investigated. In recent years, enhancements in study designs, and methodologies for systematic reviews and meta-analysis, have improved the evidence-base for nutrition policy and practice. However, these still rely on a full appreciation of the strengths and limitations of the measures on which conclusions are drawn and on the thorough investigation of outcomes that do not fit expectations or prevailing convictions. The importance of ‘hard facts’ and ‘misfits’ in research designed to advance knowledge and improve public health nutrition is illustrated in this paper through a selection of studies from different stages in my research career, focused on the nutritional requirements of resource-poor populations in Africa and Asia.

Sex differences in requirements for micronutrients across the lifecourse

For many people, micronutrient requirement means the amount needed in the diet to ensure adequacy. Dietary reference values (DRV) provide guidance on the daily intake of vitamins and minerals required to ensure the needs of the majority in the population are covered. These are developed on estimates of the quantity of each micronutrient required by the average person, the bioavailability of the micronutrient from a typical diet and the interindividual variability in these amounts. Sex differences are inherent in the requirements for many micronutrients because they are influenced by body size or macronutrient intake. These are reflected in different DRV for males and females for some micronutrients, but not all, either when data from males and females are combined or when there is no evidence of sex differences. Pregnancy and lactation represent times when micronutrient requirements for females may differ from males, and separate DRV are provided. For some micronutrients, no additional requirement is indicated during pregnancy and lactation because of physiological adaptations. To date, little account has been taken of more subtle sex differences in growth and maturation rates, health vulnerabilities and in utero and other programming effects. Over the years, the MRC Nutrition and Bone Health Group has contributed data on micronutrient requirements across the lifecourse, particularly for calcium and vitamin D, and shown that supplementation can have unexpected sex-specific consequences that require further investigation. The present paper outlines the current issues and the need for future research on sex differences in micronutrient requirements.

Sex-specific maternal calcium requirements for the prevention of nonalcoholic fatty liver disease by altering the intestinal microbiota and lipid metabolism in the high-fat-diet-fed offspring mice

The significance of maternal appropriate calcium intakes for energy metabolism in the offspring has been recognized. Nonalcoholic fatty liver disease (NAFLD) is considered as the hepatic manifestation of metabolic syndrome. So in this study, we proposed that there were long-term effects of maternal calcium status on the progress of NAFLD by altering the intestinal microbiota and lipid metabolism with attention to potential sex differences among the mouse offspring. Thirty-four-week female C57BL/6 J mice were subjected to obtain low, normal and high calcium reproductive diets throughout the gestation and lactation. After weaning, both the male and female mouse offspring were fed with the high-fat diet for 16 weeks, with the normal diet as control. Biochemical indicators in the plasma and hepatic tissue were measured using ELISA or enzymatic methods. The expression of lipid metabolism, inflammatory and fibrosis related genes was determined by RT-PCR. The intestinal microbiota was analyzed by 16S rRNA high-throughput sequencing. Maternal normal and low calcium intake could, respectively, inhibit the progress of high-fat diet induced NAFLD in the male and female mouse offspring, which was characterized by the least lipid droplets, inflammatory infiltration and fibrosis, the lowest concentrations of free fatty acids and triglyceridethe lowest expression of genes involving in de novo lipogenesis and the highest expression of genes related to lipid oxidation and  hydrolysis, inflammatory, and fibrosis. Pyrosequencing of 16S rRNA genes revealed that the male mouse offspring with maternal normal calcium intake and the female mouse offspring with maternal low calcium intake, after the high-fat diet feeding, had distinct intestinal microbiota, which was closer to thosein mice with the normal diet feeding. Analysis of the functional features for the different microbiota was compatible with the expression of genes associated with lipogenesis, lipid oxidation and hydrolysis. Thus, there is a sex-specific manner for maternal calcium requirement to inhibit the progress of offspring NAFLD, that might be less for the female offspring and more for the male offspring.

Anthropometric nutritional status, and social and dietary characteristics of African and Indian adolescents taking part in the TALENT (Transforming Adolescent Lives through Nutrition) qualitative study

OBJECTIVE

To describe the anthropometry, socioeconomic circumstances, diet and screen time usage of adolescents in India and Africa as context to a qualitative study of barriers to healthy eating and activity.

DESIGN

Cross-sectional survey, including measured height and weight and derived rates of stunting, low BMI, overweight and obesity. Parental schooling and employment status, household assets and amenities, and adolescents' dietary diversity, intake of snack foods, mobile/smartphone ownership and TV/computer time were obtained via a questionnaire.

SETTING

Four settings each in Africa (rural villages, West Kiang, The Gambia; low-income urban communities, Abidjan, Cote D'Ivoire; low/middle-class urban communities, Jimma, Ethiopia; low-income township, Johannesburg, South Africa) and India (rural villages, Dervan; semi-rural villages, Pune; city slums, Mumbai; low-middle/middle-class urban communities, Mysore).

PARTICIPANTS

Convenience samples (n 41-112 per site) of boys and girls, half aged 10-12 years and another half aged 15-17 years, were recruited for a qualitative study.

RESULTS

Both undernutrition (stunting and/or low BMI) and overweight/obesity were present in all settings. Rural settings had the most undernutrition, least overweight/obesity and greatest diet diversity. Urban Johannesburg (27 %) and Abidjan (16 %), and semi-rural Pune (16 %) had the most overweight/obesity. In all settings, adolescents reported low intakes of micronutrient-rich fruits and vegetables, and substantial intakes of salted snacks, cakes/biscuits, sweets and fizzy drinks. Smartphone ownership ranged from 5 % (West Kiang) to 69 % (Johannesburg), higher among older adolescents.

CONCLUSIONS

The 'double burden of malnutrition' is present in all TALENT settings. Greater urban transition is associated with less undernutrition, more overweight/obesity, less diet diversity and higher intakes of unhealthy/snack foods.

Effects of preventive nutrition interventions among adolescents on health and nutritional status in low- and middle-income countries: A systematic review

Background

Malnutrition is one of the most common causes of morbidity and mortality among children and adolescents and is now considered to be one of the largest risk factors responsible for the global burden of diseases along with poor diet.

Objectives

The objective of this review was to assess the impact of preventive nutrition interventions (including nutrition education and counselling; micronutrient supplementation/fortification and macronutrient supplementation) to improve the health and nutritional status of adolescents aged 10-19 years in low- and middle-income countries (LMICs). The secondary objective of the review was to assess various contextual factors based on the World Health Organisation (WHO) health system building blocks framework that might potentially impact the effectiveness of these interventions for this age group.

Search Methods

The search was conducted on Cochrane Controlled Trials Register (CENTRAL), MEDLINE, EMBASE, CINAHL, PsycINFO, the WHO nutrition databases, CAB Global Health, Social Science Citation Index, Scopus, WHO Global Health Index, ADOLEC and EPPI until February 5, 2019. We searched Google Scholar along with key nutrition agencies database such as Nutrition International, the Global Alliance for Improved Nutrition, the World Food Programme and HarvestPlus to search for nonindexed, grey literature to locate relevant programme evaluations and any additional trials. All searches were performed without any restrictions on publication date, language or publication status.

Selection Criteria

We included randomised controlled trials, quasiexperimental studies, controlled before-after studies and interrupted time series evaluating the effectiveness of preventive nutrition interventions among adolescents between 10 and 19 years of age from LMICs.

Data Collection and Analysis

Two review authors independently assessed trials for inclusion, assessed risk of bias and extracted data from included studies. Meta-analysis was conducted separately for each outcome and intervention. For dichotomous data, we reported risk ratios (RR) with 95% confidence intervals (CI). For continuous data, we reported the mean difference (MD) or standard mean difference (SMD) with 95% CI.

Main Results

This review summarises findings from a total of 10 studies from 15 papers including 10,802 participants. All the studies included in this review assessed the impact of micronutrient supplementation/fortification on health and nutritional status among adolescents in LMIC. We did not find any study assessing the impact of nutrition education and counselling or on macronutrient supplementation among adolescents. Micronutrient supplementation/fortification interventions included calcium/vitamin D supplementation/fortification, iron supplementation with or without folic acid, zinc supplementation and multiple micronutrient (MMN) fortification. The majority of the studies (eight out of 10 studies) included adolescent girls aged between 10 and 19 years of age. We did not find any large scale preventive nutrition intervention programmes targeting adolescents in LMICs. We are uncertain of the effect of iron supplementation with or without folic acid on anaemia (daily supplementation; RR: 1.04, 95% CI 0.88, 1.24; one study; 1,160 participants; low quality evidence. Weekly supplementation; RR: 1.07, 95% CI: 0.91, 1.26; one study; 1,247 participants; low quality evidence). We are uncertain of the effect of various micronutrient supplementation/fortification on body mass index (calcium/vitamin D supplementation; (MD: -0.01 kg/m2; 95% CI: -1.20, 1.17; two studies; 730 participants; I 2 94%; very low quality evidence, iron supplementation with or without folic acid; MD: 0.29 kg/m2; 95% CI: -0.25, 0.83; two studies; 652 participants; I 2 69%; very low quality evidence, zinc supplementation; MD: 0.35 kg/m2; 95% CI: -0.15, 0.85; one study; 382 participants; very low quality evidence) and MMN fortification; MD: 0.23 kg/m2, 95% CI: -0.11, 0.57; two studies; 943 participants; I 2 22%; very low quality evidence). None of the included studies reported any other primary outcomes including morbidity or adverse effects. Iron supplementation with or without folic acid may improve haemoglobin concentrations (MD: 0.42 g/dL, 95% CI: 0.13, 0.71; four studies; 1,020 participants; I 2 89%; low quality evidence). Calcium/vitamin D supplementation may improve serum 25(OH) D levels (standardised mean difference [SMD]: 2.85, 95% CI: 0.89, 4.82; two studies; 395 participants; I 2 99%; low quality evidence). We are uncertain of the effect of calcium only supplementation (MD: 0.02 g/cm2, 95% CI: -0.00, 0.04; one study; 233 participants; low quality outcome) and calcium + vitamin D supplementation (MD: 0.02 g/cm2, 95% CI: -0.00, 0.04; one study; 235 participants; low quality evidence) on total bone mineral density (BMD). We are uncertain of the effect of MMN fortification on haemoglobin concentrations (MD: -0.10 g/dL, 95% CI: -0.88, 0.68; two studies; 1102 participants; I 2 100%; very low quality evidence); calcium supplementation on total body bone mineral content (BMC); (MD: 30.20 g, 95% CI: -40.56, 100.96; one study; 233 participants; low quality evidence), calcium + vitamin D supplementation on total body BMC (MD: 21.60 g, 95% CI: -45.32, 88.52; one study; 235 participants; low quality evidence) and zinc supplementation on serum zinc levels (SMD: 6.94, 95% CI: -4.84, 18.71; two studies; 494 participants; very low quality evidence). One study reported the impact of iron supplementation with or without folic acid on cognition of adolescent girls suggesting improved cognition in most of the tests with daily or twice weekly supplementation compared to once weekly or no supplementation. None of the other secondary outcomes were reported including any other development outcomes and all-cause mortality. These findings warrant caution while interpreting due to very few studies and high heterogeneity.

Authors' Conclusions

There is limited evidence of micronutrient supplementation/fortification among adolescents on health and nutritional status in LMICs, with lack of evidence on nutrition education and counselling and macronutrient supplementation. The findings are generaliseable for adolescent girls since all studies (except one) targeted female adolescents.

Four decades of socio-economic inequality and secular change in the physical growth of Guatemalans

Objective:

To investigate changes in socio-economic inequalities in growth in height, weight, BMI and grip strength in children born during 1955–1993 in Guatemala, a period of marked socio-economic-political change.

Design:

We modelled longitudinal data on height, weight, BMI and hand grip strength using Super-Imposition by Translation and Rotation (SITAR). Internal Z-scores summarising growth size, timing and intensity (peak growth velocity, e.g. cm/year) were created to investigate inequalities by socio-economic position (SEP; measured by school attended). Interactions of SEP with date of birth were investigated to capture secular changes in inequalities.

Setting:

Urban and peri-urban schools in the region of Guatemala City, Guatemala.

Participants:

Participants were 40 484 children and adolescents aged 3–19 years of Ladino and Maya ancestry (n_observations 157 067).

Results:

The difference in height (SITAR size) between lowest and highest SEP decreased from −2·0 (95 % CI −2·2, −1·9) sd to −1·4 (95 % CI −1·5, −1·3) sd in males, and from −2·0 (95 % CI −2·1, −1·9) sd to −1·2 (95 % CI −1·3, −1·2) sd in females over the study period. Inequalities also reduced for weight, BMI and grip strength, due to greater secular increases in lowest-SEP groups. The puberty period was earlier and shorter in higher-SEP individuals (earlier SITAR timing and higher SITAR intensity). All SEP groups showed increases in BMI intensity over time.

Conclusions:

Inequality narrowed between the 1960s and 1990s. The lowest-SEP groups were still >1 sd shorter than the highest. Risks remain for reduced human capital and poorer population health for urban Guatemalans.

Prenatal influences on bone health in children

INTRODUCTION

Optimising bone health might reduce the burden of both fractures in childhood and fragility fractures in later life. A number of maternal dietary and non-dietary factors have been identified that might influence offspring bone health and represent targets for intervention.

AREAS COVERED

This article will outline the accrual of bone mineral throughout the life course and how observational and intervention studies have shown that maternal diet, in particular maternal calcium and 25-hydroxyvitamin D [25(OH)D] status, and lifestyle are associated with offspring bone mineralization. Studies examining the effects of maternal micronutrient supplementation on offspring bone mineral density (BMD) will also be discussed.

EXPERT COMMENTARY

There is a wealth of observational evidence relating maternal diet to offspring BMD. However, high quality randomized controlled trials, such as the ongoing MAVIDOS study, are needed before these findings can be definitively translated into public health advice.

Pregnancy supplementation of Gambian mothers with calcium carbonate alters mid-childhood IGF1 in a sex-specific manner

CONTEXT

Sex-specific effects of pregnancy calcium carbonate supplementation have been reported in 8-12 year old Gambian children, indicating faster growth in boys but slower growth in girls born to calcium-supplemented mothers.

OBJECTIVE

To determine whether the pregnancy supplement resulted in sex-specific effects on offspring IGF1 and other growth-related indices in mid-childhood.

DESIGN

Analysis of archived data obtained in mid-childhood from the children of rural Gambian mothers who had been randomised to 1500 mgCa/d (Ca) or placebo (P) from 20 weeks pregnancy to delivery (ISRCTN96502494).

PARTICIPANTS AND METHODS

Of the 526 children born and followed in infancy, 290 had early-morning, fasting plasma assayed for IGF1, IGFBP3, leptin, insulin and calcium-related indices and had anthropometry performed at age 7.5 (SD1.2) years (N/group: Males(M)-Ca = 64, Females(F)-Ca = 77; M-P = 76, F-P = 73). Sex-specific effects of maternal supplementation were considered using regression with sexes separated and together to test for sex ∗ supplement interactions.

RESULTS

Boys had lower IGF1, IGFBP3, leptin and insulin than girls (P ≤ 0.004). IGF1 was higher in M-Ca than M-P (+14.2 (SE7.7)%, P = 0.05) but lower in F-Ca than F-P (-17.8 (SE7.4)%, P = 0.01); sex ∗ supplement interaction P = 0.001. IGF1 concentrations (ng/ml, geometric mean [-1SE,+1SE]) were M-Ca = 78.1[4.3,4.5], M-P = 67.8[3.4,3.6]; F-Ca = 99.5[4.8,5.1], F-P = 118.9[6.4,6.8]. Similar sex ∗ supplement interactions were seen for IGFBP3 and IGF1-adjusted-for-IGFBP3 but group differences were smaller. There were no significant supplement effects on the other biochemical indices.

CONCLUSIONS

Calcium carbonate supplementation of pregnant Gambian mothers resulted in higher IGF1 in boys and lower IGF1 in girls during mid-childhood, consistent with the reported maternal supplement effects on growth of the offspring in later childhood.

Higher Longitudinal Milk Intakes Are Associated with Increased Height in a Birth Cohort Followed for 17 Years

Background

Height is an indicator of nutritional status; linear growth faltering has recognized consequences for cognitive, emotional, and chronic disease risk. Although height is routinely studied in developing countries, less attention is given to height in the United States.

Objective

The objective of this study was to identify longitudinal associations between childhood and adolescent beverage intakes, nutrient adequacy, or energy intake and height in a birth cohort.

Methods

Data for participants through ages 2-17 y (n = 717; 353 males, 364 females) recruited at birth for the longitudinal Iowa Fluoride Study (IFS) were used in the current cohort analyses. Beverage intakes (n = 708) were collected by beverage-frequency questionnaires at 3- to 6-mo intervals, whereas nutrient data (n = 652) were obtained from 3-d food diaries completed at 3- to 6-mo intervals through age 8.5 y and from Block Kids' food-frequency questionnaires at 2-y intervals after age 8.5 y. Nutrient adequacy ratios were calculated with the use of age- and sex-specific Estimated Average Requirements. Height was measured at clinic visits when the participants were approximately ages 5, 9, 11, 13, 15, and 17 y. Linear mixed models were used to identify longitudinal associations between dietary variables and height. A baseline model that adjusted for changing growth patterns during adolescence was established. Dietary and potential confounding variables were added to this baseline model.

Results

Milk intake adjusted for mean adequacy ratio, energy intake, and baseline socioeconomic status was associated with height; for each additional 8 ounces (236 mL) of milk consumed per day throughout childhood and adolescence, height increased, on average, by 0.39 cm (95% CI: 0.18, 0.60 cm; P < 0.001).

Conclusions

IFS participants' height increased by 0.39 cm for each additional 8 ounces (236 mL) of milk consumed throughout childhood and adolescence. The clinical implications of the mild linear growth faltering observed in healthy youth are unknown. This trial was registered at www.clinicaltrials.gov as 199112665.

Low-mineral direct drinking water in school may retard height growth and increase dental caries in schoolchildren in China

Although direct drinking water (DDW) systems that utilize a reverse-osmosis technique are thought to be harmful to children's development by reducing their daily mineral intake, few population data are available regarding this topic. We conducted an eco-epidemiological study to investigate the influence of low-mineral DDW on the development of schoolchildren. We collected developmental parameters of 13,723 girls and 16,161 boys before and after the introduction of DDW systems in 25 schools and measured the mineral levels in the DDW of each school. The DDW in 22 schools had lower-than-recommended levels of magnesium and calcium (magnesium, 10 mg/L and calcium, 20 mg/L, WHO). We found that children exposed to low-mineral DDW exhibited reduced height and diminished height increases as well as higher prevalences and incidences of hypoevolutism and dental caries (p < 0.01). This exposure was a risk factor for a greater incidence of both hypoevolutism and dental caries in children (RR = 7.110 (1.688, 29.953) and 1.813 (1.309, 2.509), respectively; p < 0.01). Our results suggest that low-mineral DDW may retard height growth and promote the incidence of dental caries in schoolchildren; thus, schools should choose DDW treatment systems that retain the minerals in water.

In rural Gambia, do adolescents have increased nutritional vulnerability compared with adults?

Adolescents may be particularly susceptible to malnutrition owing to the energy and nutrient costs of the pubertal growth spurt. Here, our aim is to compare differences in selected markers of nutritional status between adolescents and adults in rural Gambia. The Keneba Biobank collects cross‐sectional data and samples for all consenting individuals resident in the West Kiang region of the Gambia. For this study, participants between the ages of 10 and 40 years were selected (n = 4201, females 2447). Height, body mass index, body composition, hemoglobin concentration, fasting glucose concentration, and blood pressure were compared using linear regression models adjusting for age, parity, season of measurement, and residence, across three age groups: early adolescent (10–14.9 years), late adolescent (15–19.9 years), and adult (20–39.9 years). Adolescents, particularly early‐adolescent girls and boys, were shorter, lighter, and leaner than adults. By late adolescence, differences were smaller, particularly in girls where, notably, the prevalence of overweight, hypertension, and impaired fasting glucose was low. Given the importance of maternal health for reproductive outcomes and intergenerational health, the results of the study, albeit with limited biomarkers available, indicate that adolescent girls are no more compromised than adult women or males from the same population.

Long-term effects of maternal calcium supplementation on childhood growth differ between males and females in a population accustomed to a low calcium intake

The importance of adequate calcium intakes for healthy growth and bone development has long been recognised. Recent evidence suggests that calcium supplementation may have sex-specific effects on bone growth in childhood. The aim was to describe the long-term effects of calcium supplementation in pregnant Gambian women with a low calcium intake (ISCRTN96502494) on offspring height, weight, bone and body composition in childhood, and whether the effects differ by sex. Children of mothers who participated in the original calcium supplementation trial were measured at age 8-12years using dual-energy X-ray absorptiometry and peripheral quantitative computed tomography. Linear models tested for sex*supplement interactions before and after adjusting for current age and size in early life. 447 children, aged 9.2(SD 0.9) years, were measured. Significant sex*supplement interactions (p<0.05) were observed for many of the anthropometric and bone outcomes, Females whose mothers received calcium (F-Ca) were shorter, lighter with smaller bones and less bone mineral than those whose mothers received placebo (F-P), differences (SE) ranged from height=-1.0 (0.5)% to hip BMC -5.5 (2.3)%. Males from mothers in the calcium group (M-Ca) had greater mid-upper arm circumference (MUAC) (+2.0 (1.0)%, p=0.05) and fat mass (+11.6 (5.1)%, p=0.02) and tended towards greater BMC and size than those whose mothers were in the placebo group (M-P). The differences in anthropometry and body composition were robust to adjustment for current height and weight, whereas all bone differences became non-significant. F-P were taller with more BMC than M-P, whereas F-Ca had similar sized bones and mineral content to M-Ca. Calcium supplementation of pregnant women with low calcium intakes altered the childhood trajectories of growth and bone and body composition development of their offspring in a sex-specific manner, resulting in slower growth among females compared to placebo and accelerated growth among males by age 8-12years.

Classifying Gestational Weight Gain Trajectories Using the SITAR Growth Model

BACKGROUND

Gestational weight gain is often characterized by the total amount of weight gained during pregnancy, however, the pattern of gain may be an important determinant of health outcomes. The SITAR (Super Imposition by Translation And Rotation) model has been used to describe childhood growth trajectories and has appeal because of the biological interpretability of its parameters. The objective of this study was to determine the feasibility of applying this model to gestational weight gain trajectories.

METHODS

The study cohort included 3470 normal-weight, overweight, and obese women delivering at Magee-Womens Hospital in Pittsburgh, Pennsylvania, 1998 to 2010. We applied the SITAR model, a non-linear mixed effects model, to serial prenatal weight gain measurements in each pre-pregnancy body mass index (BMI) category. We fit models of varying complexity, and chose the best-fitting model to describe the pattern of weight gain (by its absolute amount, timing, and acceleration) for each BMI group.

RESULTS

The most complex SITAR models failed to converge, but reduced models could successfully be fit by specifying fewer random effects and simplifying the modelling of gestational age. Best-fitting models for each BMI group explained between 95% and 97% of the variation in weight gain trajectories. Peak rates of weight gain were reached between the 20th and 22nd weeks, and were higher for normal and overweight women (0.59 kg/week and 0.57 kg/week, respectively) than obese women (0.46 kg/week).

CONCLUSIONS

Following some modifications, the SITAR model can be used to characterize pregnancy weight gain patterns.

Building better bones in childhood: a randomized controlled study to test the efficacy of a dietary intervention program to increase calcium intake

Background/Objectives

Many children do not consume the recommended daily allowance of calcium. Inadequate calcium intake in childhood may limit bone accrual. The objective of this study was to determine if a behavioral modification and nutritional education (BM-NE) intervention improved dietary calcium intake and bone accrual in children.

Subjects/Methods

139 (86 female) healthy children, 7–10 years of age, were enrolled in this randomized controlled trial conducted over 36 months. Participants randomized to the BM-NE intervention attended five sessions over a six-week period designed to increase calcium intake to 1500 mg/day. Participants randomized to the usual care (UC) group received a single nutritional counseling session. The Calcium Counts^© Food Frequency Questionnaire was used to assess calcium intake; DXA was used to assess areal bone mineral density (aBMD) and bone mineral content (BMC). Longitudinal mixed effects models were used to assess for an effect of the intervention on calcium intake, BMC and aBMD.

Results

BM-NE participants had greater increases in calcium intake that persisted for 12 months following the intervention compared to UC. The intervention had no effect on BMC or aBMD accrual. Secondary analyses found a negative association between calcium intake and adiposity such that greater calcium intake was associated with lesser gains in BMI and fat mass index.

Conclusions

A family-centered BM-NE intervention program in healthy children was successful in increasing calcium intake for up to 12 months but had no effect on bone accrual. A beneficial relationship between calcium intake and adiposity was observed and warrants future study.

The Gambian Bone and Muscle Ageing Study: Baseline Data from a Prospective Observational African Sub-Saharan Study

The Gambian Bone and Muscle Ageing Study is a prospective observational study investigating bone and muscle ageing in men and women from a poor, subsistence farming community of The Gambia, West Africa. Musculoskeletal diseases, including osteoporosis and sarcopenia, form a major part of the current global non-communicable disease burden. By 2050, the vast majority of the world's ageing population will live in low- and middle-income countries with an estimated two-fold rise in osteoporotic fracture. The study design was to characterise change in bone and muscle outcomes and to identify possible preventative strategies for fracture and sarcopenia in the increasing ageing population. Men and women aged ≥40 years from the Kiang West region of The Gambia were recruited with stratified sampling by sex and age. Baseline measurements were completed in 488 participants in 2012 who were randomly assigned to follow-up between 1.5 and 2 years later. Follow-up measurements were performed on 465 participants approximately 1.7 years after baseline measurements. The data set comprises a wide range of measurements on bone, muscle strength, anthropometry, biochemistry, and dietary intake. Questionnaires were used to obtain information on health, lifestyle, musculoskeletal pain, and reproductive status. Baseline cross-sectional data show preliminary evidence for bone mineral density and muscle loss with age. Men had greater negative differences in total body lean mass with age than women following adjustments for body size. From peripheral quantitative computed tomography scans, greater negative associations between bone outcomes and age at the radius and tibia were shown in women than in men. Ultimately, the findings from The Gambian Bone and Muscle Ageing Study will contribute to the understanding of musculoskeletal health in a transitioning population and better characterise fracture and sarcopenia incidence in The Gambia with an aim to the development of preventative strategies against both.

Persistent Effect of Vitamin D Supplementation on Musculoskeletal Parameters in Adolescents One Year After Trial Completion

We showed a beneficial effect of vitamin D supplementation on musculoskeletal parameters in adolescent girls in a 1-year, randomized, double-blinded placebo-controlled trial (RCT). Our objective for this study was to investigate the residual effect of vitamin D supplementation on bone mineral content (BMC), bone mineral density (BMD), at the lumbar spine and hip, lean mass, and height, 1 year after trial completion. We performed post hoc analyses in 167 adolescents, 86 girls and 81 boys, age 13.9 ± 2 years, who received vitamin D or placebo during the trial, and continued into the follow-up trial. Musculoskeletal parameters were measured at baseline, 12 months (intervention), and 24 months (follow-up). ANOVA and t tests were used to compare results between the placebo group and the merged vitamin D arms (200 or 2000 IU/day), by gender. Baseline characteristics were comparable between treatment groups at entry into the extension. Girls who had received vitamin D during the trial, had significantly larger hip BMC increments compared to those assigned to placebo, at 24 months compared to study entry, but not 24 compared to 12 months, which persisted in adjusted analyses. There were no significant differences in bone mass changes between treatment groups in boys, at 24 months compared to 12 months or to baseline. The beneficial effect of vitamin D supplementation on hip bone mass, achieved in girls during the trial, persisted 1 year after trial completion. These net cumulative increments, 1 year after discontinuation of supplementation, may have important implications on optimizing peak bone mass accretion in adolescent girls. © 2016 American Society for Bone and Mineral Research.

Factors influencing bone mass accrual: focus on nutritional aspects

Until recently, much of the research exploring the role of nutrition on bone mass accrual has focused on single nutrients. Although randomised controlled trials have provided key information about the effects of calcium and vitamin D on bone, they also have limitations, e.g. generalisation, implementation of the results and long-term consequences. Human subjects do not eat single nutrients, but foods, and describing healthy food patterns for optimising bone mineral accrual is warranted. Recent advances in research suggest that the effects of whole diet are larger than those of single nutrients on bone health. Research should focus on younger age groups to identify the life-course determinants of osteoporosis during prenatal, infancy, childhood and adolescence that would help to maximise peak bone mass. Food patterns that describe the variability, quality and choices of individuals give broader insight and may provide new strategies for preventing osteoporosis.

The longitudinal effects of physical activity and dietary calcium on bone mass accrual across stages of pubertal development

Childhood and adolescence are critical periods of bone mineral content (BMC) accrual that may have long-term consequences for osteoporosis in adulthood. Adequate dietary calcium intake and weight-bearing physical activity are important for maximizing BMC accrual. However, the relative effects of physical activity and dietary calcium on BMC accrual throughout the continuum of pubertal development in childhood remains unclear. The purpose of this study was to determine the effects of self-reported dietary calcium intake and weight-bearing physical activity on bone mass accrual across the five stages of pubertal development in a large, diverse cohort of US children and adolescents. The Bone Mineral Density in Childhood study was a mixed longitudinal study with 7393 observations on 1743 subjects. Annually, we measured BMC by dual-energy X-ray absorptiometry (DXA), physical activity and calcium intake by questionnaire, and pubertal development (Tanner stage) by examination for up to 7 years. Mixed-effects regression models were used to assess physical activity and calcium intake effects on BMC accrual at each Tanner stage. We found that self-reported weight-bearing physical activity contributed to significantly greater BMC accrual in both sexes and racial subgroups (black and nonblack). In nonblack males, the magnitude of the activity effect on total body BMC accrual varied among Tanner stages after adjustment for calcium intake; the greatest difference between high- and low-activity boys was in Tanner stage 3. Calcium intake had a significant effect on bone accrual only in nonblack girls. This effect was not significantly different among Tanner stages. Our findings do not support differential effects of physical activity or calcium intake on bone mass accrual according to maturational stage. The study demonstrated significant longitudinal effects of weight-bearing physical activity on bone mass accrual through all stages of pubertal development.