Symposium on ‘Nutrition and health in children and adolescents’ Session 1: Nutrition in growth and development Nutrition and bone growth and development

Growing Strong and Healthy with Mister Bone: An Educational Program to Have Strong Bones Later in Life

Optimal peak bone mass and bone health later in life are favored by a sufficient calcium intake in infancy, childhood and adolescence. The purpose of this study was to test a new educational program created to monitor and to improve calcium and vitamin D intake in children. Nutritional habits in children were evaluated through a food frequency questionnaire (FFQ) to assess the intake of calcium, vitamin D, dairy products, and total caloric energy at baseline and after seven months of exposure to a unique educational program applied between November 2013 and May 2014 in 176 schoolchildren (48% male, 52% female) attending the fourth and fifth grades of two selected primary schools in Florence, Italy. A significant increase of calcium (from 870 ± 190 to 1100 ± 200 mg/day, p < 0.05), and vitamin D (from 3.6 ± 1.53 to 4.1 ± 2 µg/day) intake in children was documented after the educational program. The amount of specific foods important for bone health consumed, such as milk and vegetables, increased significantly, both in male and female children (p < 0.05). The proposed educational program appears to be effective in modifying calcium intake in children, with a significant increase in the consumption of dairy products and vegetables, but without a significant change in the total caloric intake.

Effects of school meals with weekly fish servings on vitamin D status in Danish children: secondary outcomes from the OPUS (Optimal well-being, development and health for Danish children through a healthy New Nordic Diet) School Meal Study

Children's vitamin D intake and status can be optimised to meet recommendations. We investigated if nutritionally balanced school meals with weekly fish servings affected serum 25-hydroxyvitamin D (25(OH)D) and markers related to bone in 8- to 11-year-old Danish children. We conducted an explorative secondary outcome analysis on data from 784 children from the OPUS School Meal Study, a cluster-randomised cross-over trial where children received school meals for 3 months and habitual lunch for 3 months. At baseline, and at the end of each dietary period, 25(OH)D, parathyroid hormone (PTH), osteocalcin (OC), insulin-like growth factor-1 (IGF-1), bone mineral content (BMC), bone area (BA), bone mineral density (BMD), dietary intake and physical activity were assessed. School meals increased vitamin D intake by 0·9 (95 % CI 0·7, 1·1) μg/d. No consistent effects were found on 25(OH)D, BMC, BA, BMD, IGF-1 or OC. However, season-modified effects were observed with 25(OH)D, i.e. children completing the school meal period in January/February had higher 25(OH)D status (5·5 (95 % CI 1·8, 9·2) nmol/l; P = 0·004) than children completing the control period in these months. A similar tendency was indicated in November/December (4·1 (95 % CI –0·12, 8·3) nmol/l; P = 0·057). However, the effect was opposite in March/April (–4·0 (95 % CI –7·0, –0·9) nmol/l; P = 0·010), and no difference was found in May/June (P = 0·214). Unexpectedly, the school meals slightly increased PTH (0·18 (95 % CI 0·07, 0·29) pmol/l) compared with habitual lunch. Small increases in dietary vitamin D might hold potential to mitigate the winter nadir in Danish children's 25(OH)D status while higher increases appear necessary to affect status throughout the year. More trials on effects of vitamin D intake from natural foods are needed.

Risk of fracture prevention in spina bifida patients: correlation between bone mineral density, vitamin D, and electrolyte values

PURPOSE

The aim of our study was to investigate the relationship between bone mineral density (BMD), vitamin D, and electrolyte blood values in patients with spina bifida, to find a possible therapeutic regimen and an intervention to reduce the risk of fractures in this population.

METHODS

BMD values were measured in 49 patients (32 females, 17 males; aged 14.1 ± 3.86 years; range 5-20 years) using dual-energy X-ray absorptiometry (DEXA) and were analyzed based on sex, the level of spinal involvement, vitamin D, and electrolyte values, physical activity, body mass index (BMI), and ambulatory status [patients were divided into three subgroups: full-time wheelchair (FTWC), limited ambulator (LA), and full-time ambulator (FTA)]. These data were analyzed considering sex-, age-, and BMD-matched values and compared with those of normal population.

RESULTS

BMD was significantly lower in these patients compared with that in the general healthy population (Z-score: -1.2 ± 1.8); in particular, females had Z-score values significantly lower that of the males (Z-score: -2.43 ± 2.02; P < 0.0004). In FTWC subgroup, Z-score was lower than that of the other two subgroups (P < 0.009). Vitamin D values were significantly lower compared with those in the general healthy population (vitamin D spina bifida group: 14.6 ± 8.7 mg/dL; normal subjects: 35 ± 9.8 mg/dL; P < 0.001). Subjects with spina bifida showed hypophosphatemia (<3 mg/dL) because of the lower levels of vitamin D (3.1 ± 0.9 mg/dL; P < 0.001).

CONCLUSIONS

Spina bifida patients showed lower BMD, vitamin D, and electrolyte values than the healthy population; hence, they have an increase risk of developing pathological fractures. Vitamin D supplementation for a longer time period could reduce this risk.

Infant dietary patterns and bone mass in childhood: the Generation R Study

Early life nutrition affects peak bone mass attainment. In this prospective cohort study, children with high adherence to a "dairy and whole grains" pattern in infancy had higher bone mineral density at the age of 6 years. Although the observed effects are small, our study provides insight into mechanisms linking early nutrition to bone acquisition in childhood.

INTRODUCTION

Nutrition in early life may affect peak bone mass attainment. Previous studies on childhood nutrition and skeletal health mainly focused on individual nutrients, which does not consider the cumulative effects of nutrients. We investigated the associations between dietary patterns in infancy and childhood bone health.

METHODS

This study included 2850 children participating in a population-based prospective cohort study. Dietary information was obtained from a food frequency questionnaire at the age of 13 months. Using principal component analysis, three major dietary patterns were extracted, explaining in total 30% of the variation in dietary intake. At the age of 6 years, a total body dual-energy X-ray absorptiometry (DXA) scan was performed, and bone mineral density (BMD), bone mineral content (BMC), area-adjusted BMC (aBMC), and bone area (BA) were analyzed.

RESULTS

Higher adherence score to a "dairy and whole grains" pattern was positively associated with BMD and aBMC, but not with BMC and BA. Accordingly, children in the highest quartile of the "dairy and whole grains" pattern had higher BMD (difference 3.98 mg/cm(2), 95% confidence interval (CI) 0.36 to 7.61) and aBMC (difference 4.96 g, 95% CI 1.27 to 8.64) than children in the lowest quartile. Stratification for vitamin D supplementation showed that the positive associations between the "dairy and whole grains" pattern and bone outcomes were only observed in children who did not receive vitamin D supplementation. A "potatoes, rice, and vegetables" and a "refined grains and confectionery" pattern were not consistently associated with bone outcomes.

CONCLUSIONS

An infant dietary pattern characterized by high intakes of dairy and cheese, whole grains, and eggs is positively associated with bone development in childhood. Further research is needed to investigate the consequences for bone health in later life.

Environmental temperature impact on bone and cartilage growth

Environmental temperature can have a surprising impact on extremity growth in homeotherms, but the underlying mechanisms have remained elusive for over a century. Limbs of animals raised at warm ambient temperature are significantly and permanently longer than those of littermates housed at cooler temperature. These remarkably consistent lab results closely resemble the ecogeographical tenet described by Allen's "extremity size rule," that appendage length correlates with temperature and latitude. This phenotypic growth plasticity could have adaptive significance for thermal physiology. Shortened extremities help retain body heat in cold environments by decreasing surface area for potential heat loss. Homeotherms have evolved complex mechanisms to maintain tightly regulated internal temperatures in challenging environments, including "facultative extremity heterothermy" in which limb temperatures can parallel ambient. Environmental modulation of tissue temperature can have direct and immediate consequences on cell proliferation, metabolism, matrix production, and mineralization in cartilage. Temperature can also indirectly influence cartilage growth by modulating circulating levels and delivery routes of essential hormones and paracrine regulators. Using an integrated approach, this article synthesizes classic studies with new data that shed light on the basis and significance of this enigmatic growth phenomenon and its relevance for treating human bone elongation disorders. Discussion centers on the vasculature as a gateway to understanding the complex interconnection between direct (local) and indirect (systemic) mechanisms of temperature-enhanced bone lengthening. Recent advances in imaging modalities that enable the dynamic study of cartilage growth plates in vivo will be key to elucidating fundamental physiological mechanisms of long bone growth regulation.

Food insecurity and nutritional biomarkers in relation to stature in Inuit children from Nunavik

OBJECTIVES

Inuit in Canada experience alarming levels of food insecurity, but nutritional and physiological consequences are poorly documented, especially in school-age children. The objective of this study was to assess the relation of food insecurity to iron deficiency and stature in school-aged Inuit children from Nunavik (Northern Quebec).

METHODS

Food insecurity, iron deficiency, and stature were assessed in a cohort of children. Food insecurity was determined by interviewing the children's mothers. Multiple logistic regression was used to evaluate the association of food insecurity to iron deficiency and short stature. We defined short stature as a height in the lowest tertile for age and sex, based on Canadian growth charts. The relation of food insecurity to height (cm) was analyzed with a general linear model. Statistical models controlled for age, sex, normal/overweight/obese status, prenatal lead exposure and postnatal polychlorinated biphenyls exposure.

RESULTS

Half of the children (49.7%, n=145) were food insecure, while one third were iron depleted, 12.6% had anaemia, and 8.7% had iron-deficiency anaemia. The multivariate odds ratio of anaemia was 1.82 (95% CI: 0.97, 3.42, p=0.06) for food-insecure children. Prevalence of short stature was 18.7%. Food-insecure children were an average of 2 cm shorter (95% CI: -0.48, -3.17) than food-secure children (p<0.01).

CONCLUSION

In this population, food-insecure children have greater burdens of nutritional deficiencies and slower linear growth. Considering the high prevalence of food insecurity among Inuit children in Nunavik, nutritional deficiencies and adverse effects on development should be carefully monitored.

Bone nutrients for vegetarians

The process of bone mineralization and resorption is complex and is affected by numerous factors, including dietary constituents. Although some dietary factors involved in bone health, such as calcium and vitamin D, are typically associated with dairy products, plant-based sources of these nutrients also supply other key nutrients involved in bone maintenance. Some research suggests that vegetarian diets, especially vegan diets, are associated with lower bone mineral density (BMD), but this does not appear to be clinically significant. Vegan diets are not associated with an increased fracture risk if calcium intake is adequate. Dietary factors in plant-based diets that support the development and maintenance of bone mass include calcium, vitamin D, protein, potassium, and soy isoflavones. Other factors present in plant-based diets such as oxalic acid and phytic acid can potentially interfere with absorption and retention of calcium and thereby have a negative effect on BMD. Impaired vitamin B-12 status also negatively affects BMD. The role of protein in calcium balance is multifaceted. Overall, calcium and protein intakes in accord with Dietary Reference Intakes are recommended for vegetarians, including vegans. Fortified foods are often helpful in meeting recommendations for calcium and vitamin D. Plant-based diets can provide adequate amounts of key nutrients for bone health.

Vitamin D deficiency in reproductive age Mongolian women: a cross sectional study

Vitamin D production is critical not only for rickets prevention but for its role in several chronic diseases of adulthood. Maternal vitamin D status also has consequences for the developing fetus. This study assessed the prevalence of vitamin D deficiency (serum 25-hydroxyvitamin D [25(OH)D]<20ng/ml) and insufficiency [25(OH)D=20-29ng/ml] in spring, among reproductive age Mongolian women. Blood was drawn in March and April, 2009 from 420 Mongolian women, 18-44 years of age. Serum 25(OH)D concentrations were measured, anthropometric measurements were performed and information was collected by interview on lifestyle, dietary and reproductive factors. Logarithm-transformed 25(OH)D levels were compared across risk factor categories by analysis of variance. Linear regression analysis was used to assess the independent associations of factors with vitamin D status. Cutaneous vitamin D3 synthesis was assessed between December and July using a standard 7-dehydrocholesterol ampoule model. The vast majority of women 415 (98.8%) had serum 25(OH)D<20ng/ml (50nmol/l) with an additional 4 women (<1%) in the insufficient range (20-29ng/ml); only one women (0.2%) had sufficient levels (>30ng/ml or 75nmol/l). 25(OH)D concentrations were positively and independently associated with educational status and use of vitamin D supplements, but not with other demographic, lifestyle, reproductive, or anthropometric factors. 25(OH)D levels were not associated with dietary factors in this population, as there is little access to foods containing vitamin D in Mongolia. No production of previtamin D3 was observed until March and was maximally effective in April and was sustained through July. These data suggest that the prevalence of vitamin D deficiency in spring among reproductive age women in Mongolia is high. Given the lack of naturally vitamin D-rich food in the diet and limited use of vitamin D supplements, food fortification and/or supplementation with vitamin D should be considered among these women.

Associations between a priori-defined dietary patterns and longitudinal changes in bone mineral density in adolescents

OBJECTIVE

To quantify short- and long-term associations between dietary patterns defined a priori and bone mineral density (BMD) during adolescence.

DESIGN

Dietary patterns were defined at 13 years old using a Mediterranean diet (MD) quality index, the Dietary Approaches to Stop Hypertension (DASH) diet index and the Oslo Health Study (OHS) dietary index. Linear regression coefficients were used to estimate associations between dietary patterns and forearm BMD at 13 and 17 years, measured by dual-energy X-ray absorptiometry.

SETTING

Public and private schools of Porto, Portugal.

SUBJECTS

The EPITeen cohort comprising 1180 adolescents born in 1990, recruited at schools during the 2003/2004 school year and re-evaluated in 2007/2008.

RESULTS

In girls, at 13 years, mean BMD (g/cm2) in the first and third tertiles was 0·369 and 0·368 for the MD pattern, 0·368 and 0·369 for the DASH diet, and 0·370 and 0·363 for the OHS index. In boys, mean BMD (g/cm2) in the first and third tertiles was 0·338 and 0·347 for the MD pattern, 0·342 and 0·346 for the DASH diet, and 0·344 and 0·342 for the OHS index. None of these differences were significant. Mean BMD at 17 years and prospective variation were also not significantly different between tertiles of adherence to each score. However, a trend of increased BMD at 13 years with greater adherence to the MD pattern was observed in boys (adjusted coefficient = 0·248; 95% CI 0·052, 0·444).

CONCLUSIONS

The selected dietary patterns may not capture truly important dietary differences in determining BMD or diet may not be, beyond nutrient adequacy, a limiting determinant of BMD.

Association between fruits and vegetables intake and frequency of breakfast and snacks consumption: a cross-sectional study

Background

There are very few studies on the frequency of breakfast and snack consumption and its relation to fruit and vegetable intake. This study aims to fill that gap by exploring the relation between irregular breakfast habits and snack consumption and fruit and vegetable intake in Tuscan adolescents. Separate analyses were conducted with an emphasis on the potentially modifying factors of sex and age.

Methods

Data was obtained from the 2010 Tuscan sample of the Health Behaviour in School-aged Children (HBSC) study. The HBSC study is a cross-sectional survey of 11-, 13- and 15-year-old students (n = 3291), selected from a random sample of schools. Multivariate logistic regression was used for analyzing the food-frequency questionnaire.

Results

A significant relation was found between low fruit and vegetable intake and irregular breakfast habits. Similarly, low fruit intake was associated with irregular snack consumption, whereas vegetable intake did not prove to be directly related to irregular snack consumption. Different patterns emerged when gender and age were considered as modifying factors in the analyses. A statistically significant relation emerged only among female students for irregular breakfast habits and fruit and vegetable intake. Generally, older female participants with irregular breakfast habits demonstrated a higher risk of low fruit and vegetable intake. Age pattern varied between genders, and between fruit and vegetable consumption.

Conclusions

Results suggest that for those adolescents who have an irregular consumption of breakfast and snacks, fruit intake occurs with a lower frequency. Lower vegetable consumption was associated with irregular breakfast consumption. Gender and age were shown to be moderators and this indicated the importance of analyzing fruit and vegetable intake and meal types separately.

This study also confirmed that health-promotion campaigns that aim to promote regular meal consumption and consumption of fruits and vegetables need to take into account gender and age differences in designing promotional strategies. Future research should identify evidence-based interventions to facilitate the achievement of the Italian guidelines for a healthy diet for fruit, vegetables and meals intake.

Comparative evaluation of serum levels of main minerals and postmenopausal osteoporosis

OBJECTIVE

The purpose of this study was to determine the relationship between serum main minerals and postmenopausal osteoporosis.

STUDY DESIGN

A total of 728 postmenopausal women were included in this study. Women were separated into two groups according to presence or absence of osteoporosis (OP). BMD was measured in total femur (TF), femoral neck (FN) and lumbar spine (L1-L4) by dual-energy X-ray absorptiometry. Risk factors for OP were recorded by using a structured questionnaire.

MAIN OUTCOME MEASURES

Women's blood were collected and serum concentrations of iron, copper, zinc, sodium, potassium, magnesium, calcium, ionized calcium, inorganic phosphorus were measured.

RESULTS

Low serum copper levels were significantly associated with OP according to BMD values for TF, FN and L1-L4. There was a significant relationship between low serum zinc levels and OP for L1-L4 spines. Low iron serum levels were also significantly associated with OP in BMD measurements of TF. Low serum magnesium levels had significant association with OP of L1-L4 spines and TF. Serum levels of calcium, ionized calcium, potassium, sodium and inorganic phosphorus were not associated with OP.

CONCLUSIONS

In postmenopausal women, the low serum levels of copper, zinc, iron and magnesium appear to be an important risk factor for OP.

Nutritional rickets around the world

Nutritional rickets is a major public health problem in many countries of the world. The disease is characterized by deformities of the long bones, enlargement of the wrists and costochondral junctions, hypotonia and, in infants, craniotabes and delayed fontanelle closure. Predominantly caused by severe vitamin D deficiency, rickets can also be associated with hypocalcemic seizures and cardiac failure. First presentation is typically at 6-24 months of age, although hypocalcemia may be evident in younger infants. In many affluent industrialized countries, the prevalence of rickets in the general population diminished after the introduction of clean-air legislation and dietary supplementation. However, in such countries, vitamin-D deficiency rickets has re-emerged in recent years, particularly among groups with limited exposure to UVB-containing sunshine. Infants at risk of rickets tend to be those whose mothers had poor vitamin D status during pregnancy and those exclusively breast-fed for a prolonged period with little skin exposure to UVB. In other countries of the world, the prevalence of rickets can be high, even in regions with abundant year-round UVB-containing sunshine. In general, this is also due to vitamin D deficiency related to limited sun exposure. However, reports from Africa and Asia suggest that there may be other etiological factors involved. Studies in South Africa, Nigeria, The Gambia and Bangladesh have identified rickets in children, typically 3-5 years old at first presentation, in whom plasma 25-hydroxyvitamin D concentrations are higher than those characteristic of primary vitamin D deficiency. Calcium deficiency has been implicated, and in some, but not all, disturbances of phosphate metabolism, renal compromise and iron deficiency may also be involved. Continuing studies of the etiology of nutritional rickets will provide evidence to underpin guidelines for the prevention and treatment of rickets world-wide. This article is part of a Special Issue entitled 'Vitamin D Workshop'.

Does excess weight interfere with bone mass accumulation during adolescence?

Obesity and osteoporosis are important global health problems characterized by increasing prevalence with high impact on morbidity and mortality. The objective of this review was to determine whether excess weight during adolescence interferes with bone mass accumulation. If bone mineral gain can be optimized during puberty, adults are less likely to suffer from the devastating complications of osteoporosis. The increased fracture risk in obese children has also been attributed to a lower bone mass for weight compared to non-obese children. Thus, adiposity present in this age group may not result in the protection of bone mass, in contrast to what has been observed in adults. However, studies involving adolescents have reported both protective and detrimental effects of obesity on bone. The results and mechanisms of these interactions are controversial and have not been fully elucidated, a fact highlighting the extreme relevance of this topic and the need to monitor intervening and interactive variables.

Absorption Studies Show that Phytase from Aspergillus niger Significantly Increases Iron and Zinc Bioavailability from Phytate-Rich Foods

Background

Iron and zinc deficiency are major public health problems affecting many parts of the world, including Southeast Asia. Infants, young children, and women of reproductive age are particularly vulnerable due to their high requirements. Even though iron and zinc are present in significant amounts in the plant-based diets typically consumed in developing countries, their bioavailability is low due to high levels of absorption inhibitors such as phytate. Phytase has been used in animal nutrition for decades to improve the bioavailability of certain minerals in feed.

Objective

To show the effect of phytase in human nutrition based on evidence from human studies. Phytase can be used either during processing or as an active food ingredient degrading dietary phytate during stomach transit time.

Methods

Evidence from human studies testing the effect of phytase on iron and zinc bioavailability using stable isotopes was reviewed.

Results

Twelve studies tested the effect of phytase on iron and five tested its effect on zinc bioavailability. Most of these studies used a phytase derived from Aspergillus niger. They found a beneficial effect unless phytate concentrations were too low or levels of inhibitors or enhancers of iron absorption were too high. Twenty to 320 phytase units per 100 g of flour significantly improved iron absorption, even though higher levels might further increase iron bioavailability. For zinc, not enough information is available to determine optimal activities.

Conclusions

Phytase clearly has a beneficial effect on iron and zinc absorption from phytate-rich foods. It also has the potential to increase the absorption of magnesium, calcium, and phosphorus in areas such as Southeast Asia where mineral deficiencies are widespread.

Associations of dietary calcium, vitamin D, milk intakes, and 25-hydroxyvitamin D with bone mass in Spanish adolescents: the HELENA study

Adequate nutrition is needed for the accrual of bone mass during the pre- and postpubertal growth periods. This study aimed to examine the associations between dietary calcium, vitamin D (calciferol), and milk intakes and 25-hydroxyvitamin D [25(OH)D] status and bone mineral content (BMC) and bone mineral density (BMD) in Spanish adolescents, aged 12.5-17.5 years, participating in the Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study (HELENA-CSS). Bone mass was measured with dual-energy X-ray absorptiometry and diet via 2 nonconsecutive 24-h dietary recalls (n=227; 48% males). A random subsample of 101 adolescents (46% males) had available measures of 25(OH)D. Multiple linear regression was applied. Significant adjusted associations were observed in males, among milk intakes and BMC and BMD. Also in males, whole-body, head, and right arm BMD were positively related to calcium intakes. In females, 25(OH)D was positively related among others to whole-body, subtotal, and left and right arm BMC and BMD. It could be speculated that diet is not a limiting factor of bone mass development in this group of healthy adolescents, and further research on the effect of other factors in addition to diet in a larger sample should be undertaken.

Calcium economy in human pregnancy and lactation

Pregnancy and lactation are times of additional demand for Ca. Ca is transferred across the placenta for fetal skeletal mineralisation, and supplied to the mammary gland for secretion into breast milk. In theory, these additional maternal requirements could be met through mobilisation of Ca from the skeleton, increased intestinal Ca absorption efficiency, enhanced renal Ca retention or greater dietary Ca intake. The extent to which any or all of these apply, the underpinning biological mechanisms and the possible consequences for maternal and infant bone health in the short and long term are the focus of the present review. The complexities in the methodological aspects of interpreting the literature in this area are highlighted and the inter-individual variation in the response to pregnancy and lactation is reviewed. In summary, human pregnancy and lactation are associated with changes in Ca and bone metabolism that support the transfer of Ca between mother and child. The changes generally appear to be independent of maternal Ca supply in populations where Ca intakes are close to current recommendations. Evidence suggests that the processes are physiological in humans and that they provide sufficient Ca for fetal growth and breast-milk production, without relying on an increase in dietary Ca intake or compromising long-term maternal bone health. Further research is needed to determine the limitations of the maternal response to the Ca demands of pregnancy and lactation, especially among mothers with marginal and low dietary Ca intake, and to define vitamin D adequacy for reproductive women.

Vitamin C and zinc intakes are related to bone macroarchitectural structure and strength in prepubescent girls

The extent to which nutrient intake may influence bone structure and strength during maximal rates of skeletal growth remains uncertain. We examined the relationship of dietary intake of micronutrients and bone macroarchitectural structure in young girls. This cross-sectional analysis included baseline data from 363 fourth- and sixth-grade girls enrolled in the Jump-In study. Nutrient intake was assessed using the Harvard Youth/Adolescent Food Frequency Questionnaire. Volumetric BMD (vBMD), bone geometry, and strength were measured by peripheral quantitative computed tomography. Correlations and regression modeling assessed relations between usual nutrient intake and bone parameters. In fourth-grade girls, metaphyseal and diaphyseal area and circumferences as well as diaphyseal strength were associated with vitamin C intake (r = 0.15-0.19, p < 0.05). Zinc intake was correlated with diaphyseal vBMD (r = 0.15-0.16, p < 0.05). Using multiple linear regression to adjust for important covariates, we observed significant independent associations for vitamin C and zinc with bone parameters. For every milligram per day of vitamin C intake trabecular area increased by 11 %, cortical strength improved by 14 %, and periosteal and endosteal circumferences increased by 5 and 8.6 %, respectively. For every milligram per day of zinc intake, cortical vBMD increased by <1 %. No significant associations were observed in sixth-grade girls. Results of this study suggests that vitamin C and zinc intake are positively associated with objective measures of bone geometry, size, and strength in fourth-grade girls. This indicates that potential differences in micronutrient and bone associations at various age-associated stages of bone maturation may be indicative of competing hormonal influences.

Vitamin D and calcium status in urban children attending an ambulatory clinic service in the United Arab Emirates

Background: Maintaining a normal vitamin D status is important for both skeletal and extra-skeletal health. Recent data show that vitamin D deficiency is endemic in women residing in the Arabian Gulf and is common in pregnant women and their newborns. The purpose of this study was to establish the vitamin D and calcium status of children in an urban ambulatory pediatric clinic in Abu Dhabi to determine for the prevalence of vitamin D deficiency in this cohort.

Methods: Patients were recruited prospectively from the pediatric outpatient clinic visits, if they were having blood taken for laboratory investigations other than those related to vitamin D and calcium status. The vitamin D status was compared between 4 age groups (0–0.9 y, 1–1.9 y, 2–7.9 y and 8 -14 y) using the following definitions: deficiency < 25 nmol/l, insufficiency 25–50 nmol/l and sufficiency > 50 nmol/l.

Results: A total of 183 children were included in the study. The percentage of females and males in the deficient range was 21% and 16% respectively, while 32% and 46% of females and males respectively were vitamin D sufficient. The highest prevalence of vitamin D deficiency occurred in the 8–14 y old age group with 31.2% being deficient.

Conclusions: The study highlights that in an ambulatory pediatric clinic population, peri-pubescent children are most at risk of vitamin D deficiency. This age group is often not considered in the discussion for the need for vitamin D supplementation. Serious consideration should be given to including vitamin D supplementation in a school public health program in the UAE.

Human biology at the interface of paediatrics: measuring bone mineral accretion during childhood

BACKGROUND

Professor Tanner established a paradigm for the study of growth and development that demands precise growth measurements, description of normal variability through development to adulthood, consideration of the effects of tempo and the study of factors that influence growth outcomes. The relatively new field of paediatric bone health assessment fits this paradigm and reflects the collaboration of human biologists and paediatricians in understanding the growth of the human skeleton.

REVIEW

This review describes the reasons for clinical assessment of bone density in children, the technological developments in bone health assessment in children, the development of reference curves and the effects of growth, body composition, pubertal timing, genetics and lifestyle on bone health outcomes.

Vitamin D during pregnancy and maternal, neonatal and infant health outcomes: a systematic review and meta-analysis

Vitamin D has well-defined classical functions related to calcium metabolism and bone health but also has non-classical effects that may influence other aspects of health. There has been considerable recent interest in the role of vitamin D on outcomes related to pregnancy and young child health but few efforts have been made to systematically consolidate this evidence to inform the research and policy agenda for low-income countries. A systematic review was undertaken to identify intervention and observational studies of vitamin D supplementation, intake or status (25-hydroxy-vitamin D) during pregnancy on perinatal and infant health outcomes. Data from trials and observational studies isolating the effect of vitamin D supplementation and intake were extracted and study quality was evaluated. Meta-analysis was used to pool effect estimates. We identified five randomised trials with outcomes of relevance to our review. All had small sample size and dosage amount, duration and frequency varied as did the ability to correct deficiency. Pooled analysis of trials using fixed-effects models suggested protective effects of supplementation on low birthweight (three trials, risk ratio (RR) = 0.40 [95% confidence interval (CI) 0.23, 0.71]) and non-significant but suggestive effects of daily supplementation on small-for-gestational age (two trials, RR = 0.67 [0.40, 1.11]). No effect on preterm delivery (<37 weeks) was evident (two trials, RR = 0.77 [0.35, 1.66]). Little evidence from trials exists to evaluate the effect of vitamin D supplementation during pregnancy on maternal, perinatal or infant health outcomes. Based on both trials and observational studies, we recommend that future research explore small-for-gestational age, preterm delivery, pre-eclampsia, and maternal and childhood infections, as outcomes of interest. Trials should focus on populations with a high prevalence of vitamin D deficiency, explore the relevance of timing of supplementation, and the dosage used in such trials should be sufficient to correct deficiency.

Endochondral bone growth, bone calcium accretion, and bone mineral density: how are they related?

Endochondral bone growth in young growing mammals or adult mammals with persistent growth plates progresses from proliferation, maturation and hypertrophy of growth plate chondrocytes to mineralization of cartilaginous matrix to form an osseous tissue. This complex process is tightly regulated by a number of factors with different impacts, such as genetics, endocrine/paracrine factors [e.g., PTHrP, 1,25(OH)(2)D(3), IGF-1, FGFs, and prolactin], and nutritional status (e.g., dietary calcium and vitamin D). Despite a strong link between growth plate function and elongation of the long bone, little is known whether endochondral bone growth indeed determines bone calcium accretion, bone mineral density (BMD), and/or peak bone mass. Since the process ends with cartilaginous matrix calcification, an increase in endochondral bone growth typically leads to more calcium accretion in the primary spongiosa and thus higher BMD. However, in lactating rats with enhanced trabecular bone resorption, bone elongation is inversely correlated with BMD. Although BMD can be increased by factors that enhance endochondral bone growth, the endochondral bone growth itself is unlikely to be an important determinant of peak bone mass since it is strongly determined by genetics. Therefore, endochondral bone growth and bone elongation are associated with calcium accretion only in a particular subregion of the long bone, but do not necessarily predict BMD and peak bone mass.

Perinatal maternal dietary supplementation of ω3-fatty acids transiently affects bone marrow microenvironment, osteoblast and osteoclast formation, and bone mass in male offspring

It is increasingly evident that micronutrient environment experienced before birth and in infancy is important for achieving optimal bone mass by adolescence and maintaining bone health. This study determined whether maternal supplementation with ω3-polyunsaturated fatty acids (n3FA) improved offspring bone growth and adult bone mass. Female rats were fed a diet containing 0.1% (control, n = 10) or 1% (n3FA, n = 11) docosahexanoic acid (DHA) during pregnancy and lactation. Offspring were weaned onto a control rat chow diet. Tibial growth plate and metaphysis structure, osteoblast/osteoclast density and differentiation, and gene expression were assessed in offspring at 3 wk (weaning), 6 wk (adolescent), and 3 months (adult). Maternal n3FA supplementation elevated offspring plasma n3FA levels at 3 and 6 wk. Although total growth plate heights were unaffected at any age, the resting zone thickness was increased in both male and female offspring at 3 wk. In n3FA males, but not females, bone trabecular number and thickness were increased at 3 wk but not other ages. The wk 3 n3FA males also exhibited an increased bone volume, an increased osteoblast but decreased osteoclast density, and lower expression of osteoclastogenic cytokines receptor activator of nuclear factor-κB ligand, TNF-α, and IL-6. No effects were seen at 6 wk or 3 months in either sex. Thus, perinatal n3FA supplementation is associated with increased bone formation, decreased resorption, and a higher bone mass in males, but not in females, at weaning; these effects do not persist into adolescence and adulthood and are unlikely to produce lasting improvements in bone health.

Parental income and child health in Germany

Using newly available data from Germany, we study the relationship between parental income and child health. We find a strong gradient between parental income and subjective child health as has been documented earlier in the United States, Canada, and the United Kingdom. The relationship in Germany is about as strong as in the United States and stronger than in the United Kingdom. However, in contrast to US results, we do not find consistent evidence that the disadvantages associated with low parental income accumulate as the child ages, nor that children from low socioeconomic background are more likely to suffer from doctor-diagnosed conditions. There is some evidence, however, that high-income children are better able to cope with the adverse consequences of chronic conditions. Investigating potential diagnosis bias, we find only weak evidence for health disadvantages for low-income children when using objective health measures, but some evidence for under-utilization of health services among low-income families.

Human health effects of conjugated linoleic acid from milk and supplements

The primary purpose of the present review was to determine if the scientific evidence available for potential human health benefits of conjugated linoleic acid (CLA) is sufficient to support health claims on foods based on milk naturally enriched with cis-9, trans-11-CLA (c9, t11-CLA). A search of the scientific literature was conducted and showed that almost all the promising research results that have emerged in relation to cancer, heart health, obesity, diabetes and bone health have been in animal models or in vitro. Most human intervention studies have utilised synthetic CLA supplements, usually a 50:50 blend of c9, t11-CLA and trans-10, cis-12-CLA (t10, c12-CLA). Of these studies, the only evidence that is broadly consistent is an effect on body fat and weight reduction. A previous review of the relevant studies found that 3.2 g CLA/d resulted in a modest body fat loss in human subjects of about 0.09 kg/week, but this effect was attributed to the t10, c12-CLA isomer. There is no evidence of a consistent benefit of c9, t11-CLA on any health conditions; and in fact both synthetic isomers, particularly t10, c12-CLA, have been suspected of having pro-diabetic effects in individuals who are already at risk of developing diabetes. Four published intervention studies using naturally enriched CLA products were identified; however, the results were inconclusive. This may be partly due to the differences in the concentration of CLA administered in animal and human studies. In conclusion, further substantiation of the scientific evidence relating to CLA and human health benefits are required before health claims can be confirmed.

Musculoskeletal phenotype through the life course: the role of nutrition

This review considers the definition of a healthy bone phenotype through the life course and the modulating effects of muscle function and nutrition. In particular, it will emphasise that optimal bone strength (and how that is regulated) is more important than simple measures of bone mass. The forces imposed on bone by muscle loading are the primary determinants of musculoskeletal health. Any factor that changes muscle loading on the bone, or the response of bone to loading results in alterations of bone strength. Advances in technology have enhanced the understanding of a healthy bone phenotype in different skeletal compartments. Multiple components of muscle strength can also be quantified. The critical evaluation of emerging technologies for assessment of bone and muscle phenotype is vital. Populations with low and moderate/high daily Ca intakes and/or different vitamin D status illustrate the importance of nutrition in determining musculoskeletal phenotype. Changes in mass and architecture maintain strength despite low Ca intake or vitamin D status. There is a complex interaction between body fat and bone which, in addition to protein intake, is emerging as a key area of research. Muscle and bone should be considered as an integrative unit; the role of body fat requires definition. There remains a lack of longitudinal evidence to understand how nutrition and lifestyle define musculoskeletal health. In conclusion, a life-course approach is required to understand the definition of healthy skeletal phenotype in different populations and at different stages of life.

Vitamin D in pregnancy and lactation in humans

Concerns exist about the adequacy of vitamin D in pregnant and lactating women. This review assesses the evidence that maternal vitamin D status influences maternal, fetal, and breast-fed infant bone health; maternal adverse outcomes (preeclampsia, gestational diabetes, obstructed labor, and infectious disease); fetal adverse outcomes (growth, gestational age, and developmental programming); and infant adverse outcomes. The evidence for all of these outcomes is contradictory (except for maternal infectious disease) and lacking causality; thus, it is inconclusive. The 2011 Dietary Reference Intakes for vitamin D and their implications for assessing vitamin D status are discussed. An estimated 5% to 29% of American pregnant women may have inadequate vitamin D status, with the higher prevalence in African Americans. Little is known about the prevalence of inadequacy in American lactating women. Research needs are also identified, especially the need for rigorous and well-designed randomized clinical trials to determine the role of vitamin D in nonbone health outcomes in pregnancy and lactation.

Effect of diet and lifestyle factors on bone health in postmenopausal women

Our objective was to examine the effect of nutritional intake and lifestyle factors on bone mass in postmenopausal Saudi women. A total of 122 apparently healthy postmenopausal Saudi women were recruited from the Center of Excellence for Osteoporosis Research in Jeddah. A questionnaire on lifestyle habits and dietary intake was administered to all participants. Anthropometric and bone mineral density (BMD) values were measured. Fasting blood samples were taken to measure concentrations of bone-related parameters and hormones. Most of the sample population was found to be vitamin D deficient with a serum vitamin D level below 50 nmol/l. Those participants with normal BMD values had significantly lower serum vitamin D levels than osteopenic individuals (P < 0.05). Overall, mean total caloric, total fat, and saturated fat intakes were above recommended levels. Almost 60% of the total study population had lower calcium intake than the estimated average requirements whereas the whole population had vitamin D intake level below the estimated average requirements. Only BMD of the femoral neck showed significant correlations with serum vitamin D level and dietary cholesterol intake. After adjustment for confounding variables; serum vitamin D levels were significantly correlated with cholesterol intake. Dietary calcium intake was significantly correlated with intake of protein and fiber whereas dietary vitamin D intake was significantly correlated with intake level of total fat, all fatty acids, cholesterol, and fiber. Our findings reveal the important role of dietary vitamin D and calcium in osteopenic patients and the likely requirement for supplementation of these nutrients in the Saudi population.

Effects of lifestyle and diet on bone health in young adult Chinese women living in Hong Kong and Beijing

BACKGROUND

Dietary and lifestyle variations may be too small to detect possible associations with bone mineral density (BMD) within a community. Pooled data from communities with different diets and lifestyle but of the same ethnicity may help explore these associations.

OBJECTIVE

To examine the effects of dietary and lifestyle factors on BMD in young Chinese women.

METHODS

Baseline data were analyzed from 441 women aged 20 to 35 years in Hong Kong and Beijing who were participating in a longitudinal study evaluating the effect of milk supplementation on bone health. Data on demographic characteristics, lifestyle, use of oral contraceptives, diet, physical activity, and BMD of total hip, femoral neck, and total spine measured by dual-energy x-ray absorptiometry were pooled for analysis.

RESULTS

Hong Kong subjects had significantly lower BMD and higher body-size-adjusted dietary intakes of protein, fat, fiber, vitamins, potassium, sodium, and selenium than Beijing subjects. Multivariate regression of pooled data showed that body mass index was the most important determinant of BMD at all sites. Age was negatively associated and use of oral contraceptives was positively associated with femoral neck BMD. Carbohydrate intake was positively associated with total hip BMD. Fiber intake was negatively associated with BMD at total hip and total spine. Increased vitamin E intake was associated with greater total spine BMD. None of the nutrients were associated with BMD at the femoral neck.

CONCLUSIONS

Diet, lifestyle, and BMD differed greatly between young women from Hong Kong and Beijing. Body mass index was the most important determinant of BMD in young Chinese women, whereas age, use of oral contraceptives, and diet had less pronounced effects.

Physical activity and dietary intake of children aged 9-11 years and the influence of peers on these behaviours: a 1-year follow-up

BACKGROUND

This study investigated physical activity and dietary intake of children aged 9-11 years, and the influence of peers on these behaviours over a 2-year period.

METHODS

A total of 106 (64 girls; 42 boys) children were investigated annually, over 2 years. Measures included physical activity (sealed pedometer), self-report measures of dietary intake and physical activity, and a peer influence questionnaire. Anthropometric measures of height and weight were also obtained.

RESULTS

The findings reveal insufficient energy intakes, physical activity levels and fruit and vegetable consumption but high intakes of saturated fat and sodium, over time, in both boys and girls. Both male calcium and female iron intakes were also of concern. Throughout the survey, peers were found to influence physical activity behaviour but not dietary intake.

CONCLUSIONS

The fact that youth consistently failed to meet established nutrition and physical activity recommendations highlights the importance of promoting physical activity and healthy eating to children younger than 9 years of age. The finding that peers significantly influence physical activity behaviour over time should be considered when designing new physical activity interventions aimed at young people.

Low maternal vitamin D status and fetal bone development: cohort study

Recent findings suggest that maternal vitamin D insufficiency during pregnancy has consequences for the offspring's bone health in later life. To investigate whether maternal vitamin D insufficiency affects fetal femur growth in ways similar to those seen in childhood rickets and study the timing during gestation of any effect of maternal vitamin D status, we studied 424 pregnant women within a prospective longitudinal study of maternal nutrition and lifestyle before and during pregnancy (Southampton Women's Survey). Using high-resolution 3D ultrasound, we measured fetal femur length and distal metaphyseal cross-sectional area, together with the ratio of femoral metaphyseal cross-sectional area to femur length (femoral splaying index). Lower maternal 25-hydroxyvitamin vitamin D concentration was not related to fetal femur length but was associated with greater femoral metaphyseal cross-sectional area and a higher femoral splaying index at 19 weeks' gestation [r = -0.16, 95% confidence interval (CI) -0.25 to -0.06 and r = -0.17, 95% CI -0.26 to -0.07, respectively] and at 34 weeks' gestation (r = -0.10, 95% CI -0.20 to 0.00 and r = -0.11, 95% CI -0.21 to -0.01, respectively). Three groups of women were identified with 25-hydroxyvitamin vitamin D concentrations that were sufficient/borderline (> 50 nmol/L, 63.4%), insufficient (25 to 50 nmol/L, 30.7%), and deficient (< or = 25 nmol/L, 5.9%). Across these groups, the geometric mean femoral splaying indices at 19 weeks' gestation increased from 0.074 (sufficient/borderline) to 0.078 (insufficient) and 0.084 (deficient). Our observations suggest that maternal vitamin D insufficiency can influence fetal femoral development as early as 19 weeks' gestation. This suggests that measures to improve maternal vitamin D status should be instituted in early pregnancy.

Plenary Lecture 3: Food and the planet: nutritional dilemmas of greenhouse gas emission reductions through reduced intakes of meat and dairy foods

Legally-binding legislation is now in place to ensure major reductions in greenhouse gas emissions in the UK. Reductions in intakes of meat and dairy products, which account for approximately 40% of food-related emissions, are an inevitable policy option. The present paper assesses, as far as is possible, the risk to nutritional status of such a policy in the context of the part played by these foods in overall health and well-being and their contribution to nutritional status for the major nutrients that they supply. Although meat may contribute to saturated fat intakes and a higher BMI, moderate meat consumption within generally-healthy population groups has no measurable influence on morbidity or mortality. However, high consumption of red and processed meat has been associated with increased risk of colo-rectal cancer and recent advice is to reduce intakes to a maximum of 70 g/d. Such reductions in meat and haem-Fe intake are unlikely to influence Fe status in functional terms. However, overall protein intakes would probably fall, with the potential for intakes to be less than current requirements for the elderly. Whether it is detrimental to health is uncertain and controversial. Zn intakes are also likely to fall, raising questions about child growth that are currently unanswerable. Milk and dairy products, currently specifically recommended for young children and pregnant women, provide 30-40% of dietary Ca, iodine, vitamin B12 and riboflavin. Population groups with low milk intakes generally show low intakes and poor status for each of these nutrients. Taken together it would appear that the reductions in meat and dairy foods, which are necessary to limit environmental damage, do pose serious nutritional challenges for some key nutrients. These challenges can be met, however, by improved public health advice on alternative dietary sources and by increasing food fortification.

Correlation analysis between bone mineral density and serum element contents of postmenopausal women in Xi'an urban area

The objective of this paper is to investigate the correlation between serum macro-element and trace element contents and bone mineral density (BMD) as well as the occurrence of osteoporosis. After the epidemiological investigation of 290 postmenopausal women from ages 45 to 65 in the Xi'an urban area, their blood was collected and serum concentrations of macro-elements, calcium, phosphonium, potassium, sodium, magnesium, and trace elements, zinc, iron, copper, and selenium were determined using atomic absorption spectrometry. Their BMD was measured by QDR-2000 dual-energy X-ray absorptiometry (DEXA). The correlation analysis between BMD and serum element contents was done with the software of SPSS 13.0. The correlation analysis of serum elements of postmenopausal women showed that there was a significant correlation between serum calcium and the other elements, and also a significant correlation between serum phosphonium and the others except serum potassium. The serum potassium content had a significant correlation with serum calcium, sodium and iron, but sodium content showed a significant correlation with the others except iron and selenium. In addition, copper had a significant correlation with the others except potassium and selenium. In correlation analysis between BMD and the elements contents, only did the potassium content show a significant positive correlation with BMD of lumbar vertebra and proximal femora. The comparison results between osteoporosis group, osteopenia group, and healthy group showed that there was no significant difference in the element contents between the groups, but there existed a tendency that potassium content increased with the rise of BMD. There exist significant correlations between the contents of serum elements such as calcium, phosphonium, sodium, potassium, magnesium, zinc, iron, copper, and selenium, but no significant differences in these elements contents between the osteoporosis group, osteopenia group, and healthy group. Serum potassium content shows a significant positive correlation with BMD, suggesting potassium may be involved in the development of osteoporosis in postmenopausal women.

Vitamin B(12) deficiency stimulates osteoclastogenesis via increased homocysteine and methylmalonic acid

The risk of nutrient deficiencies increases with age in our modern Western society, and vitamin B(12) deficiency is especially prevalent in the elderly and causes increased homocysteine (Hcy) and methylmalonic acid (MMA) levels. These three factors have been recognized as risk factors for reduced bone mineral density and increased fracture risk, though mechanistic evidence is still lacking. In the present study, we investigated the influence of B(12), Hcy, and MMA on differentiation and activity of bone cells. B(12) deficiency did not affect the onset of osteoblast differentiation, maturation, matrix mineralization, or adipocyte differentiation from human mesenchymal stem cells (hMSCs). B(12) deficiency caused an increase in the secretion of Hcy and MMA into the culture medium by osteoblasts, but Hcy and MMA appeared to have no effect on hMSC osteoblast differentiation. We further studied the effect of B(12), Hcy, and MMA on the formation of multinucleated tartrate-resistant acid phosphatase-positive osteoclasts from mouse bone marrow. We observed that B(12) did not show an effect on osteoclastogenesis. However, Hcy as well as MMA were found to induce osteoclastogenesis in a dose-dependent manner. On the basis of these results, we conclude that B(12) deficiency may lead to decreased bone mass by increased osteoclast formation due to increased MMA and Hcy levels.

Minerals and vitamins in bone health: the potential value of dietary enhancement

Nutrition is important to bone health, and a number of minerals and vitamins have been identified as playing a potential role in the prevention of bone diseases, particularly osteoporosis. Despite this, there is currently no consensus on maximum levels to allow in food or as dietary supplements. The benefits of supplementation of populations at risk of osteoporosis with Ca and vitamin D are well established. Prolonged supplementation of Ca and vitamin D in elderly has been shown to prevent bone loss, and in some intervention studies to prevent fragility fractures. Although P is essential to bone health, the average intake is considered to be more than sufficient and supplementation could raise intake to adverse levels. The role of vitamin K in bone health is less well defined, though it may enhance the actions of Ca and vitamin D. Sr administered in pharmacological doses as the ranelate salt was shown to prevent fragility fractures in postmenopausal osteoporosis. However, there is no hard evidence that supplementation with Sr salts would be beneficial in the general population. Mg is a nutrient implicated in bone quality, but the benefit of supplementation via foodstuffs remains to be established. A consensus on dietary supplementation for bone health should balance the risks, for example, exposure of vulnerable populations to values close to maximal tolerated doses, against evidence for benefits from randomised clinical trials, such as those for Ca and vitamin D. Feedback from community studies should direct further investigations and help formulate a consensus on dietary supplementation for bone health.

Vitamin D deficiency: a global perspective

The prevalence of clinical vitamin D deficiency (rickets and osteomalacia) is high in many parts of the world, and there is a resurgence of rickets among children of ethnic minority groups in Europe and Australasia. Plasma 25-hydroxyvitamin D concentration (25OHD) is a useful risk marker of clinical vitamin D deficiency. This review summarizes the factors that contribute to differences in 25OHD among populations and provides an overview of the prevalence of low vitamin D status worldwide. It discusses the controversies that surround the interpretation of 25OHD, other proposed indices of vitamin D adequacy and dietary reference values for vitamin D, and describes the emerging evidence that a very low calcium intake may contribute to the etiology of rickets in Africa and Asia. There is an urgent need for action to address the global burden of rickets and osteomalacia.

Health effects of soda drinking in adolescent girls in the United Arab Emirates

BACKGROUND

There is a growing concern in the medical and scientific communities about the harmful effects associated with carbonated soft drinks. In several observational studies, intake of carbonated beverages was associated with reduced bone mass, decreased calcium level in the blood, and increased fracture risk. Soda drinks is a contributing factor in the prevalence and incidence of both dental caries and obesity especially among adolescents and young adults so they are more likely to be diagnosed as diabetic.

OBJECTIVES

This study aims at studying the prevalence of soda drinking among adolescent girls and discovering its health effects.

SUBJECTS AND METHODS

A cross-sectional study was designed, and a multistage random sample was performed in schools and colleges in Dubai. A total of 275 students were selected. A self-administrative questionnaire was distributed and blood, and urine samples were collected. Anthropometric measures and laboratory investigations (lipid profile, renal function, and blood and urine electrolytes) were done.

RESULTS

Age range was 10 to 22 years, with mean of 16.2 years. Prevalence of soda drinking was 81.8%. About half of the ever-drinkers (47.5%) have tried to quit drinking. There was no significant difference in body mass index between drinkers and nondrinkers (chi(2) = 2.1, P > .05). The concentration of blood sodium was less in drinkers, whereas the concentrations of urea and creatinine were not affected by drinking. There was no significant difference in blood calcium between drinkers and non drinkers (P > .05). Drinkers were associated with higher risk of increased calcium and phosphorus excretion in urine (odds ratio, 1.1; 95% confidence interval, 0.38-3.3).

CONCLUSION

Soda drinking was associated with higher risk of obesity and decreasing level of blood calcium and increasing urinary calcium excretion, which may lead to osteoporosis later in life. Soda drinking did not have any effect on renal function tests in our study group.

Increased spontaneous osteoclastogenesis from peripheral blood mononuclear cells in phenylketonuria

Phenylketonuria (PKU) is commonly complicated by a progressive bone impairment of uncertain aetiology. The therapeutic phenylalanine (Phe)-restricted diet and the possible noxious effects of high plasma Phe concentrations on bone have previously been suggested as possible determinant factors. Since osteoclasts are involved in bone reabsorption, they could play a role in determining bone damage in PKU. The reported increased excretion of bone resorption markers in PKU patients is consistent with this hypothesis. Although different diseases characterized by bone loss have been related to increased spontaneous osteoclastogenesis from peripheral blood mononuclear cells (PBMCs), to date there is no evidence of increased osteoclast formation in PKU. In this study, we compared the spontaneous osteoclastogenesis from PBMCs in 20 patients affected by PKU with that observed in age- and sex-matched healthy subjects. Phenylketonuric patients showed the number of osteoclasts to be almost double that observed in controls (159.9 ± 79.5 and 87.8 ± 44.7, respectively; p = 0.001). Moreover, a strict direct correlation between the spontaneous osteoclastogenesis in PKU patients and the mean blood Phe concentrations in the preceding year was observed (r = 0.576; p = 0.010). An imbalance between bone formation and bone resorption might explain, at least in part, the pathogenesis of bone loss in this disease. These findings could provide new insights into the biological mechanisms underlying bone damage in PKU.

Physical activity and dietary behaviour in a population-based sample of British 10-year old children: the SPEEDY study (Sport, Physical activity and Eating behaviour: environmental Determinants in Young people)

Background

The SPEEDY study was set up to quantify levels of physical activity (PA) and dietary habits and the association with potential correlates in 9–10 year old British school children. We present here the analyses of the PA, dietary and anthropometry data.

Methods

In a cross-sectional study of 2064 children (926 boys, 1138 girls) in Norfolk, England, we collected anthropometry data at school using standardised procedures. Body mass index (BMI) was used to define obesity status. PA was assessed with the Actigraph accelerometer over 7 days. A cut-off of ≥ 2000 activity counts was used to define minutes of moderate-to-vigorous PA (MVPA). Dietary habits were assessed using the Health Behaviour in School Children food questionnaire. Weight status was defined using published international cut-offs (Cole, 2000). Differences between groups were assessed using independent t-tests for continuous data and chi-squared tests for categorical data.

Results

Valid PA data (>500 minutes per day on ≥ 3 days) was available for 1888 children. Mean (± SD) activity counts per minute among boys and girls were 716.5 ± 220.2 and 635.6 ± 210.6, respectively (p < 0.001). Boys spent an average of 84.1 ± 25.9 minutes in MVPA per day compared to 66.1 ± 20.8 among girls (p < 0.001), with an average of 69.1% of children accumulating 60 minutes each day. The proportion of children classified as overweight and obese was 15.0% and 4.1% for boys and 19.3% and 6.6% for girls, respectively (p = 0.001). Daily consumption of at least one portion of fruit and of vegetables was 56.8% and 49.9% respectively, with higher daily consumption in girls than boys and in children from higher socioeconomic backgrounds.

Conclusion

Results indicate that almost 70% of children meet national PA guidelines, indicating that a prevention of decline, rather than increasing physical activity levels, might be an appropriate intervention target. Promotion of daily fruit and vegetable intake in this age group is also warranted, possibly focussing on children from lower socioeconomic backgrounds.

Importance of calcium, vitamin D and vitamin K for osteoporosis prevention and treatment

Throughout the life cycle the skeleton requires optimum development and maintenance of its integrity to prevent fracture. Bones break because the loads placed on them exceed the ability of the bone to absorb the energy involved. It is now estimated that one in three women and one in twelve men aged >55 years will suffer from osteoporosis in their lifetime and at a cost in the UK of > 1.7 pounds x 10(9) per year. The pathogenesis of osteoporosis is multifactorial. Both the development of peak bone mass and the rate of bone loss are determined by key endogenous and exogenous factors. Ca supplements appear to be effective in reducing bone loss in women late post menopause (>5 years post menopause), particularly in those with low habitual Ca intake (<400 mg/d). In women early post menopause (<5 years post menopause) who are not vitamin D deficient, Ca supplementation has little effect on bone mineral density. However, supplementation with vitamin D and Ca has been shown to reduce fracture rates in the institutionalised elderly, but there remains controversy as to whether supplementation is effective in reducing fracture in free-living populations. Re-defining vitamin D requirements in the UK is needed since there is evidence of extensive hypovitaminosis D in the UK. Low vitamin D status is associated with an increased risk of falling and a variety of other health outcomes and is an area that requires urgent attention. The role of other micronutrients on bone remains to be fully defined, although there are promising data in the literature for a clear link between vitamin K nutrition and skeletal integrity, including fracture reduction.

Low Vitamin D Status in a Representative Sample of Youth From Québec, Canada

Background: Adequate vitamin D status is important for bone growth and mineralization and has been implicated in the regulation of autoimmunity, metabolic function, and cancer prevention. There are no reports of population-based studies on the vitamin D status of Canadian youth, a population with mandatory fortification of foods.

Methods: We measured plasma 25-hydroxyvitamin D [25(OH)D], the best indicator of vitamin D status, in a school-based cross-sectional sample of representative French Canadian youth (n = 1753) ages 9, 13, and 16 years living in Québec (latitude: 45°–48°N). Blood samples were collected from January to May 1999. We defined 25(OH)D deficiency as ≤27.5 nmol/L, hypovitaminosis as ≤37.5 nmol/L, and optimal as &gt;75.0 nmol/L.

Results: More than 93% of youth in each age and sex group had suboptimal 25(OH)D concentrations. The prevalence of 25(OH)D deficiency increased with age in both sexes (P &lt; 0.0001). It was 2%, 3%, and 13% in 9-, 13-, and 16-year-old boys and 2%, 8%, and 10% in 9-, 13-, and 16-year-old girls. Girls with higher body mass index and girls from households with lower income had lower 25(OH)D concentrations. These effects were not observed in boys.

Conclusions: Inadequate vitamin D status is a potentially serious public health problem among children and adolescents in Québec. Youth living at high latitudes in countries with and without mandatory fortification of vitamin D are likely at heightened risk of 25(OH)D deficiency. These results call for renewed efforts to ensure adequate vitamin D intake among growing children and adolescents.

Vitamin D deficiency in children and adolescents: epidemiology, impact and treatment

Vitamin D deficiency is highly prevalent among children and adolescents worldwide. The high rates of vitamin D deficiency during childhood are of major public health relevance, given the growing evidence that vitamin D deficiency may play a key role in the pathophysiology of many chronic diseases beyond rickets, including autoimmune conditions, cardiovascular diseases, and cancer. Identification, treatment, and prevention of vitamin D deficiency in childhood may therefore have profound health effects throughout the life span. In this review, we discuss the definitions, epidemiology, clinical implications, and treatment of vitamin D deficiency in children and adolescents.