Effect of calcium supplementation on bone mineral accretion in gambian children accustomed to a low-calcium diet

Calcium and Iron Nutrition through the Reproductive Life Course

BACKGROUND

Two essential micronutrients over the life course are calcium and iron, and both are especially important during the reproductive cycle. The role of calcium in maternal and offspring bone health and in the prevention of pre-eclampsia in pregnancy are well described, although results from randomised controlled trials for both outcomes vary. Iron is essential for synthesis of red blood cells, being a core component of haemoglobin, which carries oxygen around the body, and hence is key in the prevention of anaemia and sequelae.

SUMMARY

This article reviews the evidence across the reproductive life course for dietary calcium and iron intakes and health outcomes. For calcium, focusing on bone health and prevention of pre-eclampsia, for iron considering its crucial role in foetal and neonatal development and how requirements may be impacted through inflammation and infection, particularly in environments where iron availability may be low.

The role of vitamin D metabolism in regulating bone turnover in adolescents with perinatally-acquired HIV in Southern Africa: a cross-sectional study in Zimbabwe and Zambia

Vitamin D dysregulation can occur in people living with HIV, disrupting calcium homeostasis, and bone turnover. We aimed to investigate the potential mechanisms by which vitamin D regulates bone turnover in adolescents living with perinatally-acquired HIV (ALWH) in Southern Africa. A pre-planned secondary analysis was performed of baseline data from the vitamin D for adolescents with HIV to reduce musculoskeletal morbidity and immunopathology trial (PACTR20200989766029) which enrolled ALWH (11-19 yr) taking antiretroviral therapy for ≥6 mo, and recorded socio-demographic, clinical and dietary data. After over-night fasting, vitamin D metabolites (25(OH)D, 1,25(OH)2D, and 24,25(OH)2D), intact parathyroid hormone (PTH), and bone turnover markers (BTMs) (C-terminal telopeptide of type I collagen (CTX) and procollagen type 1 N-terminal propeptide (P1NP)) were measured. Tandem Mass Spectrometry measured vitamin D metabolites, while intact PTH and BTMs were analyzed by electrochemiluminescence immunoassay. Stratified by 25(OH)D (<75 vs ≥75 nmol/L), associations between standardized concentrations (β = standard deviations) of vitamin D metabolites, intact PTH and BTMs were assessed using structural equations modelling (SEM) adjusted for age, sex, and country (Zimbabwe/Zambia). Among the 842 ALWH enrolled, the median dietary calcium intake was 100 mg (IQR: 55-145). The SEM showed PTH was positively associated (β: 0.21; 95% CI, 0.1, 0.32) with 1,25(OH)2D, only when 25(OH)D was <75 vs ≥75 nmol/L (β: 0.23; 95%CI, -0.13, 0.59), with evidence of an interaction (β: -0.11; 95%CI, -0.20, -0.02). A positive relationship between 25(OH)D and 24,25(OH)2D was seen irrespective of 25(OH)D concentration. 24,25(OH)2D was inversely related to BTMs, particularly when 25(OH)D was <75 nmol/L (CTX: β: -0.15; 95% CI, -0.24, -0.06 and P1NP: β: -0.14; 95%CI, -0.22, -0.06). There was interaction between dietary calcium and 25(OH)D on PTH (β: -0.15; 95% CI, -0.22, -0.07) suggesting an interaction between low 25(OH)D and low dietary calcium which increases PTH. In conclusion, associations between 25(OH)D, PTH, 1,25(OH)2D, and BTMs in ALWH appear dependent upon 25(OH)D concentrations <75 nmol/L and calcium intake. A novel, potentially causal pathway between 25(OH)D, 24,25(OH)2D, and BTMs was seen. Findings enhance understanding of vitamin D metabolism in people living with HIV.

Rickets, resorption and revolution: An investigation into the relationship between vitamin D deficiency in childhood and osteoporosis in adulthood in an 18th-19th century population

OBJECTIVE

This study employs a Developmental Origins of Health and Disease (DOHaD) approach to assess the effect of vitamin D deficiency (VDD) in childhood on the risk of osteoporosis in adulthood in an archaeological sample of skeletons dating from the 18th to 19th centuries.

MATERIALS

Femora and lumbar vertebrae of 65 adults aged 18+ years (26 diagnosed with residual rickets and 39 without) from an 18th-19th century Quaker burial ground at Coach Lane, North Shields, England.

METHODS

Bone mineral density (BMD) was measured for the femoral neck and first four lumbar vertebrae of each individual using a dual energy X-ray absorptiometry (DXA) scanner as a proxy for assessing osteoporotic fracture risk.

RESULTS

3-way ANOVA revealed no statistically significant differences in BMD between individuals with and without residual rickets across age and sex.

CONCLUSIONS

A combination of lifestyle and environmental factors likely influenced the BMD of people buried at Coach Lane across the life course. The impact of childhood VDD on BMD later in life can be mitigated through other factors such as physical activity and diet.

SIGNIFICANCE

This is one of the first bioarchaeological studies to take a DOHaD approach to understand osteoporosis risk in 18th-19th century England. It highlights the complexity of aetiological factors for osteoporosis and that VDD in early life does not necessarily predispose a person to osteoporosis in adulthood.

LIMITATIONS

BMD is not the only indicator of osteoporosis. Microscopic methods for the assessment of childhood vitamin D deficiency, such as inter-globular dentine analysis, were not applied.

Impact of dairy supplementation on bone acquisition in children's limbs: a 12-month cluster-randomized controlled trial and meta-analysis

The impact of milk on bone health in rural preschoolers is under-researched. This study, through a clinical trial and a meta-analysis, finds that milk supplementation enhances forearm and calcaneus bone acquisition in children, supporting the benefits of daily milk consumption.

PURPOSE

This study evaluated the impact of dairy supplementation on bone acquisition in children's limbs through a cluster-randomized controlled trial and a meta-analysis.

METHODS

The trial involved 315 children (4-6 year) from Northwest China, randomized to receive either 390 ml of milk daily (n = 215) or 20-30 g of bread (n = 100) over 12 months. We primarily assessed bone mineral density (BMD) and content (BMC) changes at the limbs, alongside bone-related biomarkers, measured at baseline, the 6th and 12th months. The meta-analysis aggregated BMD or BMC changes in the forearm/legs/calcaneus from published randomized trials involving children aged 3-18 years supplemented with dairy foods (vs. control group).

RESULTS

Of 278 completed the trial, intention-to-treat analysis revealed significant increases in BMD (4.05% and 7.31%) and BMC (4.69% and 7.34%) in the left forearm at the 6th and 12th months in the milk group compared to controls (P < 0.001). The calcaneus showed notable improvements in BMD (2.01%) and BMC (1.87%) at 6 months but not at 12 months. Additionally, milk supplementation was associated with beneficial changes in bone resorption markers, parathyroid hormone (- 12.70%), insulin-like growth factor 1 (6.69%), and the calcium-to-phosphorus ratio (2.22%) (all P < 0.05). The meta-analysis, encompassing 894 children, indicated that dairy supplementation significantly increased BMD (SMD, 0.629; 95%CI: 0.275, 0.983) and BMC (SMD, 0.616; 95%CI: 0.380, 0.851) (P < 0.05) in the arms, but not in the legs (P > 0.05).

CONCLUSION

Milk supplementation significantly improves bone health in children's forearms, underscoring its potential as a strategic dietary intervention for bone development. Trial registration NCT05074836.

Cohort profile of an early life observational cohort in China: Bone and MicroBiOme onset (BAMBOO) study

PURPOSE

The Bone And MicroBiOme Onset (BAMBOO) study is an ongoing prospective observational cohort study conducted in Tianjin, China, aiming to determine age-appropriate trajectories for microbiome maturation and bone development and to identify the influence of dietary factors in the process.

PARTICIPANTS

The recruitment started in September 2021 and was completed in February 2023. A total of 1380 subjects were recruited, 690 at birth (group 1) and 690 at 6 months of age (group 2). Groups 1 and 2 will be followed up for 12 months and 36 months, respectively.

FINDINGS TO DATE

The age of the mothers was 31.1±3.7 (mean±SD), and the birth weight of infants was 3.3±0.5 kg with an incidence of caesarean section 50.4%. Food diary information of the first 100 subjects showed that 64 food items were introduced by 6 months. A pilot microbiome analysis revealed that at the species level, bacterial communities were composed of mostly Bacteroides dorei, Bacteroides vulgatus and Escherichia coli, which were consistent with that of previous reports. Feasibility assessments of breast milk vitamin D and human milk oligosaccharides were validated through certified reference measurements. The early data assessment showed a high reliability of the data generated from this study.

FUTURE PLANS

Data collection will be completed in August 2025. Four stage-statistical analyses will be performed as the cohort reaches certain age thresholds before the final report. Analysis of BAMBOO data will be used to develop age-appropriate trajectories for microbiome maturation and bone development for children aged 0-3 years and investigate the contribution of dietary factors in the process.

TRIAL REGISTRATION NUMBER

ChiCTR2100049972.

Running exercise with and without calcium supplementation from tuna bone reduced bone impairment caused by low calcium intake in young adult rats

Inadequate calcium intake during childhood and adolescence is detrimental to bone metabolism. Here, we postulated that calcium supplement prepared from tuna bone with tuna head oil should benefit for skeletal development than CaCO₃. Forty female 4-week-old rats were divided into calcium-replete diet (0.55% w/w, S1, n = 8) and low-calcium groups (0.15% w/w for 2 weeks; L; n = 32). Then L were subdivided into 4 groups (8/group), i.e., remained on L, L + tuna bone (S2), S2 + tuna head oil + 25(OH)D₃ and S2 + 25(OH)D₃. Bone specimens were collected at week 9. We found that 2 weeks on low calcium diet led to low bone mineral density (BMD), reduced mineral content, and impaired mechanical properties in young growing rats. Intestinal fractional calcium absorption also increased, presumably resulting from higher plasma 1,25(OH)₂D₃ (1.712 ± 0.158 in L vs. 1.214 ± 0.105 nM in S1, P < 0.05). Four-week calcium supplementation from tuna bone further increased calcium absorption efficacy, which later returned to the basal level by week 9. Calcium supplementation successfully restored BMD, bone strength and microstructure. However, 25(OH)D₃ + tuna head oil + tuna bone showed no additive effect. Voluntary running also effectively prevented bone defects. In conclusion, both tuna bone calcium supplementation and exercise are effective interventions for mitigating calcium-deficient bone loss.

Formula Milk Supplementation and Bone Acquisition in 4-6 Years Chinese Children: A 12-Month Cluster-Randomized Controlled Trial

Dairy foods are crucial for adequate calcium intake in young children, but scarce data are available on the effects of formula milk on bone acquisition. This cluster-randomized controlled trial investigated the effects of the supplementation of formula milk on bone health in rural children accustomed to a low-calcium diet between September 2021 and September 2022. We recruited 196 healthy children aged 4-6 years from two kindergartens in Huining County, Northwest China. A class-based randomization was used to assign them to receive 60 g of formula milk powder containing 720 mg calcium and 4.5 µg vitamin D or 20-30 g of bread per day for 12 months, respectively. Bone mineral density (BMD) and bone mineral content (BMC) at the left forearm and calcaneus, bone biomarkers, bone-related hormones/growth factors, and body measures were determined at baseline, 6, and 12 months. A total of 174 children completed the trial and were included in the analysis. Compared with the control group, formula milk intervention showed significant extra increments in BMD (3.77% and 6.66%) and BMC (4.55% and 5.76%) at the left forearm at 6th and 12th months post-intervention (all p < 0.001), respectively. Similar trends were observed in BMD (2.83%) and BMC (2.38%) in the left calcaneus at 6 months (p < 0.05). The milk intervention (vs. control) also showed significant changes in the serum concentrations of osteocalcin level (-7.59%, p = 0.012), 25-hydroxy-vitamin-D (+5.54%, p = 0.001), parathyroid hormone concentration (-15.22%, p = 0.003), and insulin-like growth factor 1 (+8.36%, p = 0.014). The percentage increases in height were 0.34%, 0.45%, and 0.42% higher in the milk group than in the control group after 3-, 6-, and 9-month intervention, respectively (p < 0.05). In summary, formula milk supplementation enhances bone acquisition at the left forearm in young Chinese children.

The Relationship between Dietary Pattern and Bone Mass in School-Age Children

Early bone accrual significantly influences adult bone health and osteoporosis incidence. We aimed to investigate the relationship between dietary patterns (DPs), bone mineral content (BMC) and bone mineral density (BMD) in school-age children in China. Children aged six-nine years (n = 465) were enrolled in this cross-sectional study. DPs were identified by principal component factor analysis. Total body (TB) and total body less head (TBLH) BMC and BMD were measured using dual-energy X-ray absorptiometry. Five DPs were identified. After adjustment for covariates, multiple linear regression analysis showed that the "fruit-milk-eggs" dietary pattern was positively associated with TB (β = 10.480; 95% CI: 2.190, 18.770) and TBLH (β = 5.577; 95% CI: 0.214, 10.941) BMC, the "animal organs-refined cereals" pattern was associated with low TB BMC (β = -10.305; 95% CI: -18.433, -2.176), TBLH BMC (β = -6.346; 95% CI: -11.596, -1.096), TB BMD (β = -0.006; 95% CI: -0.011, -0.001) and TBLH BMD (β = -0.004; 95% CI: -0.007, -0.001). In conclusion, our study recommends home or school meals should be rich in fruit, milk, eggs with a moderate amount of vegetables, coarse grains and meat to promote bone development for school-age children.

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.

Exploring influences on adolescent diet and physical activity in rural Gambia, West Africa: food insecurity, culture and the natural environment

OBJECTIVE

To explore, from the perspectives of adolescents and caregivers, and using qualitative methods, influences on adolescent diet and physical activity in rural Gambia.

DESIGN

Six focus group discussions (FGD) with adolescents and caregivers were conducted. Thematic analysis was employed across the data set.

SETTING

Rural region of The Gambia, West Africa.

PARTICIPANTS

Participants were selected using purposive sampling. Four FGD, conducted with forty adolescents, comprised: girls aged 10-12 years; boys aged 10-12 years; girls aged 15-17 years, boys aged 15-17 years. Twenty caregivers also participated in two FGD (mothers and fathers).

RESULTS

All participants expressed an understanding of the association between salt and hypertension, sugary foods and diabetes, and dental health. Adolescents and caregivers suggested that adolescent nutrition and health were shaped by economic, social and cultural factors and the local environment. Adolescent diet was thought to be influenced by: affordability, seasonality and the receipt of remittances; gender norms, including differences in opportunities afforded to girls, and mother-led decision-making; cultural ceremonies and school holidays. Adolescent physical activity included walking or cycling to school, playing football and farming. Participants felt adolescent engagement in physical activity was influenced by gender, seasonality, cultural ceremonies and, to some extent, the availability of digital media.

CONCLUSIONS

These novel insights into local understanding should be considered when formulating future interventions. Interventions need to address these interrelated factors, including misconceptions regarding diet and physical activity that may be harmful to health.

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 .

Impact of serum calcium levels on total body bone mineral density: A mendelian randomization study in five age strata

BACKGROUND & AIMS

Mendelian randomization (MR) studies have reported the causal association between serum calcium levels and bone mineral density (BMD). The results showed that genetically increased serum calcium levels in individuals with normal calcium levels did not increase BMD and could even reduce BMD. However, whether there are differences in the association between serum calcium and BMD in different age strata remains unclear.

METHODS

We selected eight serum calcium genetic variants with genome-wide significance (P < 5.00E-08) as the potential instrumental variables. We conducted an MR analysis to evaluate the impact of serum calcium levels on total body BMD in five age strata, 0-15, 15-30, 30-45, 45-60, and ≥60 years, using large-scale serum calcium (61,079 individuals) and total body BMD genome-wide association study (66,628 individuals) datasets. For pleiotropy analysis, we used a manual method and four common statistical methods, namely the MR-Egger intercept, MR-PRESSO, heterogeneity, and Steiger filtering tests. For MR analysis, we selected four MR methods, namely inverse-variance weighted, weighted median, MR-Egger, and MR-PRESSO. In addition to the univariable MR analysis, we conducted a multivariate MR analysis taking into account the effect of serum parathyroid hormone levels.

RESULTS

Univariable MR analysis using the inverse-variance weighted method indicated that per 0.5-mg/dL increase (about 1 standard deviation) in serum calcium levels was statistically significantly associated with reduced total body BMD only in the ≥60 years stratum (effect estimate (beta) = -0.545, 95% confidence interval (CI): -0.892 to -0.198, P = 0.002). The weighted median regression (beta = -0.446, 95% CI: -0.821 to -0.094, P = 1.40E-02) and MR-PRESSO (beta = -0.545, 95% CI: -0.892 to -0.198, P = 0.022) MR methods further supported this suggestive association. The multivariable MR analysis also found a significant association between increased serum calcium levels and reduced total body BMD in the ≥60 years stratum (beta = -0.547, 95% CI: -0.934 to -0.16, P = 0.006).

CONCLUSIONS

Our results provide genetic evidence that increased serum calcium levels did not improve BMD in the general population and that the elevated serum calcium levels in generally healthy populations, especially in adults older than 60 years, may even reduce the BMD. Our results are comparable with those of recent MR findings.

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.

Factors influencing peak bone mass gain

Bone mass is a key determinant of osteoporosis and fragility fractures. Epidemiologic studies have shown that a 10% increase in peak bone mass (PBM) at the population level reduces the risk of fracture later in life by 50%. Low PBM is possibly due to the bone loss caused by various conditions or processes that occur during adolescence and young adulthood. Race, gender, and family history (genetics) are responsible for the majority of PBM, but other factors, such as physical activity, calcium and vitamin D intake, weight, smoking and alcohol consumption, socioeconomic status, age at menarche, and other secondary causes (diseases and medications), play important roles in PBM gain during childhood and adolescence. Hence, the optimization of lifestyle factors that affect PBM and bone strength is an important strategy to maximize PBM among adolescents and young people, and thus to reduce the low bone mass or osteoporosis risk in later life. This review aims to summarize the available evidence for the common but important factors that influence bone mass gain during growth and development and discuss the advances of developing high PBM.

Dietary Patterns and Pediatric Bone

PURPOSE OF REVIEW

Much of what we know about dietary patterns (DPs) and bone is derived from cross-sectional studies in adults. Given, establishing healthy bones during childhood serves as a blueprint for adult bone, it is important to better understand the role of DPs on pediatric bone. The purpose of this review is to determine if DPs influence bone strength in children.

RECENT FINDINGS

The majority of studies investigating the role of DPs on pediatric bone are cross-sectional in design and examine data-derived "a posterori" DPs. Overall, the DPs characterized by high intakes of fruits and vegetables demonstrated positive effects on pediatric bone. Results from both "a posteriori" and "a priori" DPs approaches in children suggests that DPs dominated by the intake of fruits and vegetables might be beneficial for pediatric bone. Future studies may consider "a priori" DPs interventions to better understand relationship between DPs and pediatric bone.

Low Bone Mineral Density in Early Pubertal Transgender/Gender Diverse Youth: Findings From the Trans Youth Care Study

CONTEXT

Transgender youth may initiate GnRH agonists (GnRHa) to suppress puberty, a critical period for bone-mass accrual. Low bone mineral density (BMD) has been reported in late-pubertal transgender girls before gender-affirming therapy, but little is known about BMD in early-pubertal transgender youth.

OBJECTIVE

To describe BMD in early-pubertal transgender youth.

DESIGN

Cross-sectional analysis of the prospective, observational, longitudinal Trans Youth Care Study cohort.

SETTING

Four multidisciplinary academic pediatric gender centers in the United States.

PARTICIPANTS

Early-pubertal transgender youth initiating GnRHa.

MAIN OUTCOME MEASURES

Areal and volumetric BMD Z-scores.

RESULTS

Designated males at birth (DMAB) had below-average BMD Z-scores when compared with male reference standards, and designated females at birth (DFAB) had below-average BMD Z-scores when compared with female reference standards except at hip sites. At least 1 BMD Z-score was < -2 in 30% of DMAB and 13% of DFAB. Youth with low BMD scored lower on the Physical Activity Questionnaire for Older Children than youth with normal BMD, 2.32 ± 0.71 vs. 2.76 ± 0.61 (P = 0.01). There were no significant deficiencies in vitamin D, but dietary calcium intake was suboptimal in all youth.

CONCLUSIONS

In early-pubertal transgender youth, BMD was lower than reference standards for sex designated at birth. This lower BMD may be explained, in part, by suboptimal calcium intake and decreased physical activity-potential targets for intervention. Our results suggest a potential need for assessment of BMD in prepubertal gender-diverse youth and continued monitoring of BMD throughout the pubertal period of gender-affirming therapy.

Association between Dairy Intake and Linear Growth in Chinese Pre-School Children

Stunting remains a major public health issue for pre-school children globally. Dairy product consumption is suboptimal in China. The aim of this study was to investigate the relationship between dairy intake and linear growth in Chinese pre-school children. A national representative survey (Chinese Nutrition and Health Surveillance) of children aged under 6 years was done in 2013. Stratified multistage cluster sampling was used to select study participants. A food frequency questionnaire was used to collect dietary information. We calculated height-for-age Z-scores (HAZs) and estimated stunting using the 2006 WHO growth standard. In total, 12,153 children aged two to four years old (24 to <60 months) were studied from 55 counties in 30 provinces in China. Approximately 39.2% (4759/12,153) of those children consumed dairy at least once per day, 11.9% (1450/12,153) consumed dairy at least once in the last week, and nearly half (48.9%, 5944/12,153) did not have any dairy in the last week. The HAZ was −0.15 ± 1.22 and the prevalence of stunting was 6.5% (785/12,153). The HAZ for children who consumed dairy at least once per day or per week was 0.11 points or 0.13 points higher than the children without dairy intake. The risk of stunting for children who consumed dairy at least once per day was 28% lower than the children without dairy intake in the last week, and the risk was similar between weekly dairy consumption and no dairy consumption (AOR: 1.03, 95% CI: 0.74–1.42) after adjusting for potential confounders, including socioeconomic characteristics, lifestyle, health status, and the intake frequency of other foods. Dairy intake was significantly associated with a higher HAZ and a lower risk of stunting for children aged 2–4 years old in China. The proportion of dairy intake was still low in Chinese pre-school children. The promotion of dairy consumption might be an effective and feasible measurement for improving linear growth in Chinese pre-school children.

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.

Effects of Preventive Nutrition Interventions among Adolescents on Health and Nutritional Status in Low- and Middle-Income Countries: A Systematic Review and Meta-Analysis

The objective of this review was to assess the impact of preventive nutrition interventions on health and nutritional status of adolescents aged 10–19 years in low- and middle-income countries (LMICs). We searched the databases until 5 February 2019 without any restrictions on publication, date, language, or publication status. A total of 10 studies (15 papers) including 10,802 participants assessing the impact of micronutrient supplementation/fortification were included in this review. We did not find any study assessing the impact of nutrition education and counseling or macronutrient supplementation among adolescents. Among primary outcomes, we are uncertain of the effect of iron supplementation with or without folic acid on anemia (daily supplementation; relative risk (RR): 1.04, 95% confidence interval (CI) 0.42, 2.57; one study; 1160 participants; low-quality evidence; weekly supplementation; RR: 1.07, 95% CI: 0.46, 2.52; one study; 1247 participants; low-quality evidence). We are also uncertain of the effect of various micronutrient supplementation/fortification on body mass index (BMI) (calcium/vitamin D supplementation; (MD: −0.01 kg/m²; 95% CI: −1.20, 1.17; two studies; 730 participants; I² 94%; very-low-quality evidence, iron supplementation with or without folic acid; MD: 0.47 kg/m²; 95% CI: −0.17, 1.11; two studies; 652 participants; I² 37%; 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 multiple micronutrient (MMN) fortification; MD: 0.23 kg/m², 95% CI: −0.11, 0.57; two studies; 943 participants; I² 22%; very-low-quality evidence). None of the included studies reported any other primary outcomes including morbidity or adverse effects. Among secondary outcomes, iron supplementation with or without folic acid may improve hemoglobin concentrations, and calcium/vitamin D supplementation may improve serum 25(OH)D levels, while calcium only supplementation and calcium and vitamin D supplementation may marginally improve total body bone mineral density (BMD). We are uncertain of the effect of MMN fortification on hemoglobin concentrations, calcium supplementation on total body bone mineral content (BMC), calcium + vitamin D supplementation on total body BMC, and zinc supplementation on zinc levels. There is limited evidence of micronutrient supplementation/fortification among adolescents, especially adolescent boys, on health and nutritional status in LMICs. These findings should be interpreted with caution due to the low quality and limited number of studies.

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.

The good, the bad, and the ugly of calcium supplementation: a review of calcium intake on human health

Calcium is an important integrative component of the human body and critical for human health. It has been well established that calcium intake is helpful in the prevention and treatment of osteoporosis, which has become one of the most serious public health problems across the world. However, community-dwelling adults with and without osteoporosis are rarely concerned or even not aware of the potential side effects of high or inappropriate doses of calcium intake. Some recent studies have revealed that excessive calcium intake might increase the risks of cardiovascular diseases. The purpose of this article was to review the health benefits, costs, and consequences of calcium supplementation on osteoporosis/osteoporotic fractures, cardiovascular events, kidney stones, gastrointestinal diseases, and other important diseases. In the end, we suggest that calcium supplementation should be prescribed and taken cautiously, accounting for individual patients' risks and benefits. Clearly, further studies are needed to examine the health effects of calcium supplementation to make any solid recommendations for people of different genders, ages, and ethnicities.

Assessing bone mineral changes in response to vitamin D supplementation using natural variability in stable isotopes of Calcium in Urine

Osteoporosis is a chronic disease of public health importance, particularly in low and middle income countries. Measuring the bone mineral balance (BMB) in a non-invasive manner, and its response to different interventions, is critical to the definition of optimal strategies for its prevention and management. In this study, we demonstrate the usefulness of natural variability in calcium isotopes (δ^44/40Ca) of urine and the derived BMB estimates as a biomarker of bone health and its responsiveness to interventions. Vitamin D₃ is commonly used as a supplement for the prevention and treatment of osteoporosis, along with calcium supplements. We studied the effect of a short term vitamin D₃ supplementation on changes in urine δ^44/40Ca and the derived BMB. δ^44/40Ca before and after the vitamin D₃ supplementation yielded a statistically significant change (p = 0.050) with a positive δ^44/40Ca enrichment. The mean derived BMB was net positive (0.04 ± 0.05) in comparison to a net negative value for the control group (−0.03 ± 0.01). These results indicate the potential usefulness of urinary natural δ^44/40Ca and the derived BMB, which, along with bone mineral density could be used as a sensitive marker for precision in the prevention and treatment of osteoporosis.

Increased calcium uptake and improved trabecular bone properties in intestinal alkaline phosphatase knockout mice

Previous studies have demonstrated a negative correlation between intestinal alkaline phosphatase (IAP) activity and calcium (Ca) absorption in the gut, as IAP acts as a protective mechanism inhibiting high Ca entry into enterocytes, preventing Ca overload. Here we evaluated Ca absorption and bone properties in knockout mice (KO) completely devoid of duodenal IAP (Akp3 ^-/- mice). Female C57BL/6 control mice (WT, n = 7) and KO mice (n = 10) were used to determine Ca absorption in vivo and by in situ isolated duodenal loops followed by histomorphometric analysis of duodenal villi and crypts. Bone mineral density, morphometry, histomorphometry and trabecular connectivity and biomechanical properties were measured on bones. We observed mild atrophy of the villi with lower absorption surface and a significantly higher Ca uptake in KO mice. While no changes were seen in cortical bone, we found better trabecular connectivity and biomechanical properties in the femurs of KO mice compared to WT mice. Our data indicate that IAP KO mice display higher intestinal Ca uptake, which over time appears to correlate with a positive effect on the biomechanical properties of trabecular bone.

Whole egg consumption and cortical bone in healthy children

Eggs contain bioactive compounds thought to benefit pediatric bone. This cross-sectional study shows a positive link between childhood egg intake and radius cortical bone. If randomized trials confirm our findings, incorporating eggs into children's diets could have a significant impact in preventing childhood fractures and reducing the risk of osteoporosis.

INTRODUCTION

This study examined the relationships between egg consumption and cortical bone in children.

METHODS

The cross-sectional study design included 294 9-13-year-old black and white males and females. Three-day diet records determined daily egg consumption. Peripheral quantitative computed tomography measured radius and tibia cortical bone. Body composition and biomarkers of bone turnover were assessed using dual-energy X-ray absorptiometry and ELISA, respectively.

RESULTS

Egg intake was positively correlated with radius and tibia cortical bone mineral content (Ct.BMC), total bone area, cortical area, cortical thickness, periosteal circumference, and polar strength strain index in unadjusted models (r = 0.144-0.224, all P < 0.050). After adjusting for differences in race, sex, maturation, fat-free soft tissue mass (FFST), and protein intakes, tibia relationships were nullified; however, egg intake remained positively correlated with radius Ct.BMC (r = 0.138, P = 0.031). Egg intake positively correlated with total body bone mineral density, BMC, and bone area in the unadjusted models only (r = 0.119-0.224; all P < 0.050). After adjusting for covariates, egg intake was a positive predictor of radius FFST (β = 0.113, P < 0.050) and FFST was a positive predictor of Ct.BMC (β = 0.556, P < 0.050) in path analyses. There was a direct influence of egg on radius Ct.BMC (β = 0.099, P = 0.035), even after adjusting for the mediator, FFST (β = 0.137, P = 0.020). Egg intake was positively correlated with osteocalcin in both the unadjusted (P = 0.005) and adjusted (P = 0.049) models.

CONCLUSION

If the positive influence of eggs on Ct.BMC observed in this study is confirmed through future randomized controlled trials, whole eggs may represent a viable strategy to promote pediatric bone development and prevent fractures.

Adolescent Undernutrition: Global Burden, Physiology, and Nutritional Risks

BACKGROUND

Adolescents, comprised of 10-19 year olds, form the largest generation of young people in our history. There are an estimated 1.8 billion adolescents in the world, with 90% residing in low- and middle-income countries. The burden of disease among adolescents has its origins in infectious and injury-related causes, but nutritional deficiencies, suboptimal linear growth, and undernutrition are major public health problems, even as overweight may be on the rise in many contexts. Summary and Key Messages: Girls are most vulnerable to the influences of cultural and gender norms, which often discriminate against them. Dietary patterns and physical activity, in addition to schooling and countervailing social norms for early marriage, influence health and nutritional well-being of adolescents. Nutrient requirements - -including those for energy, protein, iron, calcium, and -others - increase in adolescence to support adequate growth and development. In settings where dietary intakes are suboptimal, anemia and micronutrient deficiencies are high. Endocrine factors are essential for promoting normal adolescent growth and are sensitive to undernutrition. Growth velocity increases during puberty when peak height velocity occurs and catch-up is possible; in girls, about 15-25% of adult height is attained. A premature pregnancy can halt linear growth and increase the risk of adverse birth outcomes. Research is needed to fill the huge data gaps related to nutrition and growth during adolescence, in addition to testing interventions during this second window of opportunity to enhance growth and development, improve human capital, and to end the intergenerational cycle of growth failure.

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.

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.

Low Habitual Dietary Calcium and Linear Growth from Adolescence to Young Adulthood: results from the China Health and Nutrition Survey

Evidences from clinical trials and meta-analyses of calcium supplementation in linear growth have given conflicting results, and few longitudinal studies have investigated the long-term associations between dietary calcium and linear growth, especially in the population with low-calcium plant-based diets. We investigated the prospective associations of low habitual dietary calcium with adult height and height-for-age z-score (HAZ) from adolescence to adulthood among 2019 adolescents from the China Health and Nutrition Survey (CHNS). The average dietary calcium intakes were 426(standard deviation: 158) mg/d in boys and 355(134) mg/d in girls during adolescence. During a median follow-up of 7.0 (interquartile range: 5.9–9.0) years, boys reached an average of 169.0(6.7) cm and girls reached 158.4(5.8) cm in adulthood. After adjusting for other potential confounders, non-linear regression found that boys with dietary calcium intakes below 327 mg/d had shorter adult stature, and those taking over 566 mg/d had faster height growth whether adjusting for physical exercises level or not. No significant associations were found in girls. Our study suggests that in boys with plant-based diets, higher dietary calcium intake during adolescence is associated with faster height growth, but not with adult height; calcium intake below 300 mg/d may result in shorter adult stature.

The Impact of Nutritional Interventions beyond the First 2 Years of Life on Linear Growth: A Systematic Review and Meta-Analysis

A large body of evidence suggests that the first 1000 d from conception is a critical window in which interventions to address malnutrition will be most effective, but little is known about the impact on linear growth of nutritional interventions in children ≥2 y of age. The aim of this analysis was to evaluate the effectiveness of several nutrition-based interventions, specifically iron, zinc, calcium, iodine, vitamin A, multiple (≥2) micronutrients, protein, and food, at improving growth in children ≥2 y of age. A systematic search of MEDLINE and EMBASE retrieved 7794 articles. A total of 69 studies met prespecified inclusion criteria. Baseline height-for-age z score, age, nutrient dose, and study duration were examined as potential sources of heterogeneity. Zinc (mean effect size: 0.15; 95% CI: 0.06, 0.24), vitamin A (0.05; 95% CI: 0.01, 0.09), multiple micronutrients (0.26; 95% CI: 0.13, 0.39), and protein (0.68; 95% CI: 0.30, 1.05) had significant positive effects on linear growth, with baseline height-for-age z score as a significant inverse predictor of the effect size. Iron, calcium, iodine, and food-based interventions had no significant effect on growth. Age at baseline, study duration, and dose were not related to effect size for any nutrient examined. These findings suggest that zinc, vitamin A, multiple micronutrients, and protein interventions delivered after 24 mo of age can have a positive effect on linear growth, especially in populations that have experienced growth failure.

Optimal Dose of Calcium for Treatment of Nutritional Rickets: A Randomized Controlled Trial

Calcium supplementation is indicated for the treatment of nutritional rickets. Our aim was to determine the optimal dose of calcium for treatment of children with rickets. Sixty-five Nigerian children with radiographically confirmed rickets were randomized to daily supplemental calcium intake of 500 mg (n = 21), 1000 mg (n = 23), or 2000 mg (n = 21). Venous blood, radiographs, and forearm areal bone density (aBMD) were obtained at baseline and at 8, 16, and 24 weeks after enrollment. The primary outcome was radiographic healing, using a 10-point radiographic severity score. The radiographic severity scores improved in all three groups, but the rate of radiographic healing (points per month) was significantly more rapid in the 1000-mg (-0.29; 95% confidence interval [CI] -0.13 to -0.45) and 2000-mg (-0.36; 95% CI -0.19 to -0.53) supplementation groups relative to the 500-mg group. The 2000-mg group did not heal more rapidly than the 1000-mg group. Of those who completed treatment for 24 weeks, 12 (67%), 20 (87%), and 14 (67%) in the 2000-mg, 1000-mg, and 500-mg groups, respectively, had achieved a radiographic score of 1.5 or less (p = 0.21). Serum alkaline phosphatase decreased and calcium increased similarly in all groups. Forearm diaphyseal aBMD improved significantly more rapidly in the 2000-mg group than in the 500-mg and 1000-mg groups (p < 0.001). Daily calcium intakes of 1000 mg or 2000 mg produced more rapid radiographic healing of rickets than 500 mg, but 2000 mg did not have greater benefit than 1000 mg. Some children require longer than 24 weeks for complete healing of nutritional rickets. © 2016 American Society for Bone and Mineral Research.

Nutrient Intake Is Insufficient among Senegalese Urban School Children and Adolescents: Results from Two 24 h Recalls in State Primary Schools in Dakar

Due to rapid urbanization and high food prices and in the absence of nutrition programs, school children from urban areas in West Africa often have insufficient and inadequate diet leading to nutrient deficiencies that affect their health and schooling performance. Acute malnutrition and micronutrient deficiencies are prevalent in children from primary state schools of Dakar (Senegal). The objectives of the present study were to assess the overall diet of these children, to report insufficient/excessive energy and nutrient intakes and to investigate association between insufficient nutrient intake and micronutrient deficiencies. Children attending urban state primary schools in the Dakar area were selected through a two-stage random cluster sampling (30 schools × 20 children). Dietary intake data were obtained from two 24 h recalls and blood samples were collected from 545 children (aged 5-17 years, 45% < 10 years, 53% girls) and adjusted for intra-individual variability to estimate nutrient usual intakes. Energy intake was insufficient and unbalanced with insufficient contribution of protein and excessive contribution of fat to global energy intake in one third of the children. Proportions of children with insufficient intake were: 100% for calcium, 100% for folic acid, 79% for vitamin A, 69% for zinc, 53% for vitamin C and 46% for iron. Insufficient iron and protein intake were risk factors for iron deficiency (odds ratio, OR 1.5, 2.2). Insufficient zinc intake and energy intake from protein were risk factors for zinc deficiency (OR 1.8, 3.0, 1.7, 2.9). Insufficient iron and vitamin C intake, and insufficient energy intake from protein were risk factors for marginal vitamin A status (OR 1.8, 1.8, 3.3). To address nutritional deficiencies associated with a diet deficient in energy, protein and micronutrients, nutrition education or school feeding programs are needed in urban primary schools of Senegal.

Cow's Milk Allergy and Bone Mineral Density in Prepubertal Children

BACKGROUND AND OBJECTIVES

Recent data suggest that cow's milk allergy (CMA) has become more persistent, prolonging treatment via strict elimination of cow's milk products into a period of skeletal growth. The objectives of this study were to compare bone mineral density (BMD), vitamin D status, and dietary intakes of calcium and vitamin D between prepubertal children with persistent CMA and those with non-cow's milk food allergies (NCMA) as control subjects and to assess the use of and compliance to calcium and vitamin D supplementation among children with persistent CMA.

METHODS

Fifty-two children with persistent CMA and 29 with NCMA were recruited. BMD was measured by using dual energy radiograph absorptiometry, and vitamin D status was assessed by using plasma 25-hydroxyvitamin D concentrations. Calcium and vitamin D intakes, as well as compliance to calcium and vitamin D supplementation, were recorded.

RESULTS

Lumbar spine BMD z scores were significantly lower in children with CMA. Low bone mass was detected in 6% of the CMA group compared with none in the NCMA group. Children with CMA displayed significantly lower calcium intakes than control subjects. Vitamin D status was not reduced in children with CMA compared with control subjects. Fewer than one-half of children with CMA reported the use of calcium and vitamin D supplements. However, adherence was high among supplement users, with a mean compliance rate of 5.5 days per week.

CONCLUSIONS

These prepubertal children with persistent CMA had lower lumbar spine BMD z scores than children with NCMA, which likely resulted from lower calcium intake.

The National Osteoporosis Foundation's position statement on peak bone mass development and lifestyle factors: a systematic review and implementation recommendations

Lifestyle choices influence 20-40 % of adult peak bone mass. Therefore, optimization of lifestyle factors known to influence peak bone mass and strength is an important strategy aimed at reducing risk of osteoporosis or low bone mass later in life. The National Osteoporosis Foundation has issued this scientific statement to provide evidence-based guidance and a national implementation strategy for the purpose of helping individuals achieve maximal peak bone mass early in life. In this scientific statement, we (1) report the results of an evidence-based review of the literature since 2000 on factors that influence achieving the full genetic potential for skeletal mass; (2) recommend lifestyle choices that promote maximal bone health throughout the lifespan; (3) outline a research agenda to address current gaps; and (4) identify implementation strategies. We conducted a systematic review of the role of individual nutrients, food patterns, special issues, contraceptives, and physical activity on bone mass and strength development in youth. An evidence grading system was applied to describe the strength of available evidence on these individual modifiable lifestyle factors that may (or may not) influence the development of peak bone mass (Table 1). A summary of the grades for each of these factors is given below. We describe the underpinning biology of these relationships as well as other factors for which a systematic review approach was not possible. Articles published since 2000, all of which followed the report by Heaney et al. [1] published in that year, were considered for this scientific statement. This current review is a systematic update of the previous review conducted by the National Osteoporosis Foundation [1]. [Table: see text] Considering the evidence-based literature review, we recommend lifestyle choices that promote maximal bone health from childhood through young to late adolescence and outline a research agenda to address current gaps in knowledge. The best evidence (grade A) is available for positive effects of calcium intake and physical activity, especially during the late childhood and peripubertal years-a critical period for bone accretion. Good evidence is also available for a role of vitamin D and dairy consumption and a detriment of DMPA injections. However, more rigorous trial data on many other lifestyle choices are needed and this need is outlined in our research agenda. Implementation strategies for lifestyle modifications to promote development of peak bone mass and strength within one's genetic potential require a multisectored (i.e., family, schools, healthcare systems) approach.

Selecting best-fit models for estimating the body mass from 3D data of the human calcaneus

Body mass (BM) estimation could facilitate the interpretation of skeletal materials in terms of the individual's body size and physique in forensic anthropology. However, few metric studies have tried to estimate BM by focusing on prominent biomechanical properties of the calcaneus. The purpose of this study was to prepare best-fit models for estimating BM from the 3D human calcaneus by two major linear regression analysis (the heuristic statistical and all-possible-regressions techniques) and validate the models through predicted residual sum of squares (PRESS) statistics. A metric analysis was conducted based on 70 human calcaneus samples (29 males and 41 females) taken from 3D models in the Digital Korean Database and 10 variables were measured for each sample. Three best-fit models were postulated by F-statistics, Mallows' Cp, and Akaike information criterion (AIC) and Bayes information criterion (BIC) for each available candidate models. Finally, the most accurate regression model yields lowest %SEE and 0.843 of R(2). Through the application of leave-one-out cross validation, the predictive power was indicated a high level of validation accuracy. This study also confirms that the equations for estimating BM using 3D models of human calcaneus will be helpful to establish identification in forensic cases with consistent reliability.

The Preventive Effect of Calcium Supplementation on Weak Bones Caused by the Interaction of Exercise and Food Restriction in Young Female Rats During the Period from Acquiring Bone Mass to Maintaining Bone Mass

Increasing calcium (Ca) intake is important for female athletes with a risk of weak bone caused by inadequate food intake. The aim of the present study was to examine the preventive effect of Ca supplementation on low bone strength in young female athletes with inadequate food intake, using the rats as an experimental model. Seven-week-old female Sprague-Dawley rats were divided into four groups: the sedentary and ad libitum feeding group (SED), voluntary running exercise and ad libitum feeding group (EX), voluntary running exercise and 30% food restriction group (EX-FR), and a voluntary running exercise, 30% food-restricted and high-Ca diet group (EX-FR+Ca). To Ca supplementation, we used 1.2% Ca diet as "high-Ca diet" that contains two-fold Ca of normal Ca diet. The experiment lasted for 12 weeks. As a result, the energy availability, internal organ weight, bone strength, bone mineral density, and Ca absorption in the EX-FR group were significantly lower than those in the EX group. The bone strength and Ca absorption in the EX-FR+Ca group were significantly higher than those in the EX-FR group. However, the bone strength in the EX-FR+Ca group did not reach that in the EX group. These results suggested that Ca supplementation had a positive effect on bone strength, but the effect was not sufficient to prevent lower bone strength caused by food restriction in young female athletes.

Prevalence of rickets-like bone deformities in rural Gambian children

The aim of this study was to estimate the burden of childhood rickets-like bone deformity in a rural region of West Africa where rickets has been reported in association with a low calcium intake. A population-based survey of children aged 0.5-17.9 years living in the province of West Kiang, The Gambia was conducted in 2007. 6221 children, 92% of those recorded in a recent census, were screened for physical signs of rickets by a trained survey team with clinical referral of suspected cases. Several objective measures were tested as potential screening tools. The prevalence of bone deformity in children <18.0 years was 3.3%. The prevalence was greater in males (M = 4.3%, F = 2.3%, p < 0.001) and in children <5.0 years (5.7%, M = 8.3%, F = 2.9%). Knock-knee was more common (58%) than bow-leg (31%) or windswept deformity (9%). Of the 196 examined clinically, 36 were confirmed to have a deformity outside normal variation (47% knock-knee, 53% bow-leg), resulting in more conservative prevalence estimates of bone deformity: 0.6% for children <18.0 years (M = 0.9%, F = 0.2%), 1.5% for children < 5.0 years (M = 2.3%, F = 0.6%). Three of these children (9% of those with clinically-confirmed deformity, 0.05% of those screened) had active rickets on X-ray at the time of medical examination. This emphasises the difficulties in comparing prevalence estimates of rickets-like bone deformities from population surveys and clinic-based studies. Interpopliteal distance showed promise as an objective screening measure for bow-leg deformity. In conclusion, this population survey in a rural region of West Africa with a low calcium diet has demonstrated a significant burden of rickets-like bone deformity, whether based on physical signs under survey conditions or after clinical examination, especially in boys < 5.0 years.

The Child with Multiple Fractures, What Next?

Fractures are common during childhood; however, they can also be the presenting symptom of primary or secondary causes of bone fragility. The challenge is to identify those children who warrant further investigation. In children who present with multiple fractures that are not commonly associated with mild to moderate trauma or whose fracture count is greater than what is typically seen for their age, an initial evaluation, including history, physical examination, biochemistry, and spinal radiography, should be performed. In children with bone pain or evidence of more significant bone fragility, referral for specialist evaluation and consideration of pharmacologic treatment may be warranted.

Peak bone strength is influenced by calcium intake in growing rats

In this study we investigated the effect of supplementing the diet of the growing male rat with different levels of calcium (from low to higher than recommended intakes at constant Ca/P ratio), on multiple factors (bone mass, strength, size, geometry, material properties, turnover) influencing bone strength during the bone accrual period. Rats, age 28days were supplemented for 4weeks with high Ca (1.2%), adequate Ca (0.5%) or low Ca level (0.2%). Bone metabolism and structural parameters were measured. No changes in body weight or food intake were observed among the groups. As anticipated, compared to the adequate Ca intake, low-Ca intake had a detrimental impact on bone growth (33.63 vs. 33.68mm), bone strength (-19.7% for failure load), bone architecture (-58% for BV/TV) and peak bone mass accrual (-29% for BMD) due to the hormonal disruption implied in Ca metabolism. In contrast, novel, surprising results were observed in that higher than adequate Ca intake resulted in improved peak bone strength (106 vs. 184N/mm for the stiffness and 61 vs. 89N for the failure load) and bone material properties (467 vs. 514mPa for tissue hardness) but these effects were not accompanied by changes in bone mass, size, microarchitecture or bone turnover. Hormonal factors, IGF-I and bone modeling were also evaluated. Compared to the adequate level of Ca, IGF-I level was significantly lower in the low-Ca intake group and significantly higher in the high-Ca intake group. No detrimental effects of high Ca were observed on bone modeling (assessed by histomorphometry and bone markers), at least in this short-term intervention. In conclusion, the decrease in failure load in the low calcium group can be explained by the change in bone geometry and bone mass parameters. Thus, improvements in mechanical properties can be explained by the improved quality of intrinsic bone tissue as shown by nanoindentation. These results suggest that supplemental Ca may be beneficial for the attainment of peak bone strength and that multiple factors linked to bone mass and strength should be taken into account when setting dietary levels of adequate mineral intake to support optimal peak bone mass acquisition.

[Advances in the treatment of secondary osteoporosis]

Osteoporosis is being increasingly recognised in paediatric practice as a consequence of the increasing life expectancy of children who suffer from chronic diseases and other factors. There are many non-pharmacological measures that can improve children' bone health, for example, avoiding inflammatory activity and osteotoxic treatments; increasing sun exposure and weight-bearing exercise, and maintaining an adequate nutritional status. Vitamin D and calcium supplements have been proposed as a measure to increase bone mass, but their effect and therapeutic indications are not completely clear. On the other hand, bisphosphonates are currently the only pharmacological alternative for the patients with infantile secondary osteoporosis. However, more studies are required on the therapeutic indications, posology, and long term secondary effects of biphosphonates. The aim of this article is to analyze the scientific evidence of the effectiveness of the therapeutic alternatives for childhood secondary osteoporosis and their safety in children.

Calcium supplementation and bone mineral accretion in Chinese adolescents aged 12–14 years: a 12-month, dose–response, randomised intervention trial

A 12-month, dose–response, randomised, intervention trial was conducted to determine adequate Ca intake levels for Chinese adolescents by investigating the effect of Ca supplementation on bone mineral accretion. A total of 220 Han adolescents (111 girls and 109 boys) aged 12–14 years were recruited. All subjects were randomly divided into three groups. The bone mineral content (BMC) and bone mineral density (BMD) of the whole body, lumbar spine (L1–L4), left hip and femoral neck were measured by dual-energy X-ray absorptiometry. Girls in the high-Ca group (actual Ca intake: 1243 (sd 193) mg/d) exhibited greater increases in the femoral neck BMC compared with those in the low-Ca group (9·7 v. 6·4 %, P =0·04) over the 1-year intervention period. The increases in femoral neck BMC were greater in boys in the high-Ca and medium-Ca groups (actual Ca intake: 985 (sd 168) mg/d) than in those in the low-Ca group (15·7 v. 11·7 %, P =0·03; 15·8 v. 11·7 %, P =0·03). Ca supplementation had significant effects on the whole-body BMC and BMD in subjects with physical activity levels>34·86 metabolic equivalents and on the spine BMD and BMC and BMD of most sites in subjects with Tanner stage < 3. Increasing Ca intake levels with Ca supplementation enhanced femoral neck mineral acquisition in Chinese adolescents. Furthermore, high physical activity levels and low Tanner stage appeared to significantly contribute to the effect of Ca supplementation on bone mass. Whether this is a lasting beneficial effect leading to the optimisation of peak bone mass needs to be determined in other long-term prospective studies.

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

CONTEXT

Calcium intake during growth is essential for future bone health but varies widely between individuals and populations. The impact on bone of increasing calcium intake is unknown in a population where low calcium intake, stunting, and delayed puberty are common.

OBJECTIVE

To determine the effect of prepubertal calcium supplementation on mean age at peak velocity for bone growth and mineral accrual.

DESIGN AND SETTING

Prospective follow-up of boys in rural Gambia, West Africa, who had participated in a double-blind, randomized, placebo-controlled trial of calcium supplementation.

PARTICIPANTS

Eighty boys, initially aged 8.0-11.9 years, were followed up for 12 years.

INTERVENTIONS

Subjects received 1 year of calcium carbonate supplementation (1000 mg daily, 5 d/wk).

MAIN OUTCOME MEASURES

Dual-energy x-ray absorptiometry measurements were carried out for whole body (WB), lumbar spine, and total hip bone mineral content, bone area (BA), and WB lean mass. Super imposition by translation and rotation models was made to assess bone growth.

RESULTS

Age at peak velocity was consistently earlier in the calcium group compared to the placebo group, for WB bone mineral content (mean, -6.2 [SE, 3.1]; P = .05), WB BA (mean, -7.0 [SE, 3.2] mo; P = .03), lumbar spine and total hip BA. By young adulthood, supplementation did not change the amount of bone accrued (mineral or size) or the rate of bone growth.

CONCLUSIONS

Twelve months of prepubertal calcium carbonate supplementation in boys with a low calcium diet advanced the adolescent growth spurt but had no lasting effect on bone mineral or bone size. There is a need for caution when applying international recommendations to different populations.

Dietary mineral supplies in Africa

Dietary micronutrient deficiencies (MNDs) are widespread, yet their prevalence can be difficult to assess. Here, we estimate MND risks due to inadequate intakes for seven minerals in Africa using food supply and composition data, and consider the potential of food-based and agricultural interventions. Food Balance Sheets (FBSs) for 46 countries were integrated with food composition data to estimate per capita supply of calcium (Ca), copper (Cu), iron (Fe), iodine (I), magnesium (Mg), selenium (Se) and zinc (Zn), and also phytate. Deficiency risks were quantified using an estimated average requirement (EAR) 'cut-point' approach. Deficiency risks are highest for Ca (54% of the population), followed by Zn (40%), Se (28%) and I (19%, after accounting for iodized salt consumption). The risk of Cu (1%) and Mg (<1%) deficiency are low. Deficiency risks are generally lower in the north and west of Africa. Multiple MND risks are high in many countries. The population-weighted mean phytate supply is 2770 mg capita(-1) day(-1). Deficiency risks for Fe are lower than expected (5%). However, 'cut-point' approaches for Fe are sensitive to assumptions regarding requirements; e.g. estimates of Fe deficiency risks are 43% under very low bioavailability scenarios consistent with high-phytate, low-animal protein diets. Fertilization and breeding strategies could greatly reduce certain MNDs. For example, meeting HarvestPlus breeding targets for Zn would reduce dietary Zn deficiency risk by 90% based on supply data. Dietary diversification or direct fortification is likely to be needed to address Ca deficiency risks.

Evidence of an overweight/obesity transition among school-aged children and youth in Sub-Saharan Africa: a systematic review

BACKGROUND

Prevalence of childhood overweight/obesity has increased considerably in recent years. The transition to higher rates of overweight/obesity has been well documented in high income countries; however, consistent or representative data from lower income countries is scarce. It is therefore pertinent to assess if rates of overweight/obesity are also increasing in lower income countries, to inform public health efforts.

OBJECTIVE

This systematic review aimed to investigate the evidence for an overweight/obesity transition occurring in school-aged children and youth in Sub Saharan Africa.

METHODS

Studies were identified by searching the MEDLINE, Embase, Africa Index Medicus, Global Health, Geobase, and EPPI-Centre electronic databases. Studies that used subjective or objective metrics to assess body composition in apparently healthy or population-based samples of children and youth aged 5 to 17 years were included.

RESULTS

A total of 283 articles met the inclusion criteria, and of these, 68 were used for quantitative synthesis. The four regions (West, Central, East, and South) of Sub Saharan Africa were well represented, though only 11 (3.9%) studies were nationally representative. Quantitative synthesis revealed a trend towards increasing proportions of overweight/obesity over time in school-aged children in this region, as well as a persistent problem of underweight. Weighted averages of overweight/obesity and obesity for the entire time period captured were 10.6% and 2.5% respectively. Body composition measures were found to be higher in girls than boys, and higher in urban living and higher socioeconomic status children compared to rural populations or those of lower socioeconomic status.

CONCLUSIONS

This review provides evidence for an overweight/obesity transition in school-aged children in Sub Saharan Africa. The findings of this review serve to describe the region with respect to the growing concern of childhood overweight/obesity, highlight research gaps, and inform interventions.

PROSPERO REGISTRATION NUMBER

CRD42013004399.

Bone mineral density in Nigerian children after discontinuation of calcium supplementation

BACKGROUND

Nigerian toddlers with low dietary calcium intakes increased forearm bone mineral density (BMD) after 18 months of calcium supplementation compared with placebo. However, it is not known if this bone mineral accretion is sustained after calcium supplement withdrawal. We therefore investigated the influence of prior calcium supplementation on forearm BMD 12 months after withdrawal of the supplement.

METHODS

Nigerian toddlers aged 12-18 months from three urban communities were enrolled in a controlled trial of calcium supplementation. Two communities received daily calcium supplements, one as calcium carbonate (400mg), and the other as ground fish (529±109 mg), for a duration of 18 months, and all three communities received vitamin A (2500 IU daily) as placebo. Forearm BMD was measured 5 times during 18 months of calcium supplementation and at 12 months after supplement withdrawal.

RESULTS

Of 647 children enrolled, 390 completed the trial of calcium supplementation and 261 of these returned for the final follow-up 12 months after discontinuation of supplementation. During the 18 months of supplementation, an adjusted model demonstrated that the increase in both distal and proximal forearm BMD over time was significantly greater in the calcium supplemented groups than in the placebo group (P<0.04). However, after supplement withdrawal, the increase in BMD over time was largely attenuated and only remained significant at the proximal forearm in the ground fish group (P=0.03).

CONCLUSION

The benefit of calcium supplementation on forearm BMD in young Nigerian children is not sustained after supplement withdrawal.

Critical windows for nutritional interventions against stunting

An analysis of early growth patterns in children from 54 resource-poor countries in Africa and Southeast Asia shows a rapid falloff in the height-for-age z score during the first 2 y of life and no recovery until ≥5 y of age. This finding has focused attention on the period -9 to 24 mo as a window of opportunity for interventions against stunting and has garnered considerable political backing for investment targeted at the first 1000 d. These important initiatives should not be undermined, but the objective of this study was to counteract the growing impression that interventions outside of this period cannot be effective. We illustrate our arguments using longitudinal data from the Consortium of Health Oriented Research in Transitioning collaboration (Brazil, Guatemala, India, Philippines, and South Africa) and our own cross-sectional and longitudinal growth data from rural Gambia. We show that substantial height catch-up occurs between 24 mo and midchildhood and again between midchildhood and adulthood, even in the absence of any interventions. Longitudinal growth data from rural Gambia also illustrate that an extended pubertal growth phase allows very considerable height recovery, especially in girls during adolescence. In light of the critical importance of maternal stature to her children's health, our arguments are a reminder of the importance of the more comprehensive UNICEF/Sub-Committee on Nutrition Through the Life-Cycle approach. In particular, we argue that adolescence represents an additional window of opportunity during which substantial life cycle and intergenerational effects can be accrued. The regulation of such growth is complex and may be affected by nutritional interventions imposed many years previously.

The effect of prepubertal calcium carbonate supplementation on the age of peak height velocity in Gambian adolescents

BACKGROUND

Limited evidence suggests that calcium intake before puberty influences adolescent height growth and the timing of puberty. Such an effect might be particularly marked in populations in whom low calcium intake, stunting, and delayed puberty are common.

OBJECTIVE

The objective was to test whether 12 mo of calcium supplementation at age 8-12 y to increase intakes toward international recommendations had long-term effects on adolescent growth and pubertal development in rural Gambian children.

DESIGN

This was a longitudinal study of 160 Gambian boys (n = 80) and girls (n = 80) who had participated in a 12-mo, randomized, double-blind, placebo-controlled, calcium carbonate supplementation trial (1000 mg Ca/d, 5 d/wk) at age 8-12 y. Anthropometric measures were made every 1-2 y until age 21-25 y; pubertal status and menarche data were collected. Repeated-measures ANCOVA and Superimposition by Translation and Rotation Method (SITAR) growth models were used to assess the effects of treatment.

RESULTS

In boys, midadolescent height growth was advanced in the calcium group, which resulted in greater stature at a mean age of 15.5 y (mean ± SEM: 2.0 ± 0.8 cm; P = 0.01) and an earlier age of peak height velocity by 7.4 ± 2.9 mo. Subsequently, the calcium group stopped growing earlier (P = 0.02) and was 3.5 ± 1.1 cm shorter (P = 0.002) at a mean age of 23.5 y. Weight and midupper arm circumference paralleled height. No significant effects were observed in girls, but a sex-by-supplement interaction on height growth could not be confirmed.

CONCLUSION

Calcium supplementation of boys in late childhood advanced the age of peak height velocity and resulted in shorter adult stature in a population in whom low calcium intakes and delayed puberty are common. This trial was registered at isrctn.org as ISRCTN28836000.