Randomized trial of physical activity and calcium supplementation on bone mineral content in 3- to 5-year-old children

Calcium revisited: part II calcium supplements and their effects

Calcium supplements were tested in pregnancy and lactation, in childhood and adolescence, in pre- and postmenopausal women and in elderly persons with various effects on bone density and fracture incidence. They must be properly chosen and adequately used. In this case, the reported minor negative side-effects do not restrict their use. All these aspects are reviewed here.

A review of preschool children's physical activity and sedentary time using objective measures

CONTEXT

Identifying current physical activity levels and sedentary time of preschool children is important for informing government policy and community initiatives. This paper reviewed studies reporting on physical activity and time spent sedentary among preschool-aged children (2-5 years) using objective measures.

EVIDENCE ACQUISITION

Databases were searched for studies published up to and including April 2013 that reported on, or enabled the calculation of, the proportion of time preschool children spent sedentary and in light- and moderate to vigorous-intensity physical activity. A total of 40 publications met the inclusion criteria for physical activity and 31 met the inclusion criteria for sedentary time. Objective measures included ActiGraph, Actiwatch, Actical, Actiheart, and RT3 accelerometers, direct observation, and Quantum XL telemetry heart rate monitoring. Data were analyzed in May 2013.

EVIDENCE SYNTHESIS

Considerable variation in prevalence estimates existed. The proportion of time children spent sedentary ranged from 34% to 94%. The time spent in light-intensity physical activity and moderate to vigorous-intensity physical activity ranged from 4% to 33% and 2% to 41%, respectively.

CONCLUSIONS

The considerable variation of prevalence estimates makes it difficult to determine the "true" prevalence of physical activity and sedentary time in preschool children. Future research should aim to reduce inconsistencies in the employed methodologies to better understand preschoolers' physical activity levels and sedentary behavior.

Bone morbidity in childhood leukemia: epidemiology, mechanisms, diagnosis, and treatment

Skeletal abnormalities are commonly seen in children and adolescents with leukemia. The spectrum ranges from mild pain to debilitating osteonecrosis (ON) and fractures. In this review, we summarize the skeletal manifestations, provide an update on therapeutic strategies for prevention and treatment, and discuss the most recent advances in musculoskeletal research. Early recognition of skeletal abnormalities and strategies to optimize bone health are essential to prevent long-term skeletal sequelae and diminished quality of life observed in children and adolescents with leukemia.

A 6-year exercise program improves skeletal traits without affecting fracture risk: a prospective controlled study in 2621 children

Most pediatric exercise intervention studies that evaluate the effect on skeletal traits include volunteers and follow bone mass for less than 3 years. We present a population-based 6-year controlled exercise intervention study in children with bone structure and incident fractures as endpoints. Fractures were registered in 417 girls and 500 boys in the intervention group (3969 person-years) and 835 girls and 869 boys in the control group (8245 person-years), all aged 6 to 9 years at study start, during the 6-year study period. Children in the intervention group had 40 minutes daily school physical education (PE) and the control group 60 minutes per week. In a subcohort with 78 girls and 111 boys in the intervention group and 52 girls and 54 boys in the control group, bone mineral density (BMD; g/cm(2) ) and bone area (mm(2) ) were measured repeatedly by dual-energy X-ray absorptiometry (DXA). Peripheral quantitative computed tomography (pQCT) measured bone mass and bone structure at follow-up. There were 21.7 low and moderate energy-related fractures per 1000 person-years in the intervention group and 19.3 fractures in the control group, leading to a rate ratio (RR) of 1.12 (0.85, 1.46). Girls in the intervention group, compared with girls in the control group, had 0.009 g/cm(2) (0.003, 0.015) larger gain annually in spine BMD, 0.07 g (0.014, 0.123) larger gain in femoral neck bone mineral content (BMC), and 4.1 mm(2) (0.5, 7.8) larger gain in femoral neck area, and at follow-up 24.1 g (7.6, 40.6) higher tibial cortical BMC (g) and 23.9 mm(2) (5.27, 42.6) larger tibial cross-sectional area. Boys with daily PE had 0.006 g/cm(2) (0.002, 0.010) larger gain annually in spine BMD than control boys but at follow-up no higher pQCT values than boys in the control group. Daily PE for 6 years in at study start 6- to 9-year-olds improves bone mass and bone size in girls and bone mass in boys, without affecting the fracture risk.

Evidence for an interaction between exercise and nutrition for improving bone and muscle health

Regular exercise and adequate nutrition, particularly dietary calcium, vitamin D, and protein, are prescribed as strategies to optimize peak bone mass and maintain bone and muscle health throughout life. Although the mechanism of action of exercise and nutrition on bone and muscle health are different-exercise has a site-specific modifying effect, whereas nutrition has a permissive generalized effect-there is evidence that combining calcium (or calcium rich dairy foods) or dietary protein with exercise can have a synergetic effect on bone mass and muscle health, respectively. However, many questions still remain as to whether there is a threshold level for these nutrients to optimize the exercise-induced gains. Further studies are also needed to investigate whether other dietary factors, such as vitamin D, soy isoflavones or omega-3 fatty acids, or a multinutrient supplement, can enhance the effects of exercise on bone and muscle health.

Bone densitometry in infants and young children: the 2013 ISCD Pediatric Official Positions

Infants and children <5 yr were not included in the 2007 International Society for Clinical Densitometry Official Positions regarding Skeletal Health Assessment of Children and Adolescents. To advance clinical care of very young children, the International Society for Clinical Densitometry 2013 Position Development Conference reviewed the literature addressing appropriate methods and skeletal sites for clinical dual-energy X-ray absorptiometry (DXA) measurements in infants and young children and how results should be reported. DXA whole-body bone mineral content and bone mineral density for children ≥3 yr and DXA lumbar spine measurements for infants and young children 0-5 yr were identified as feasible and reproducible. There was insufficient information regarding methodology, reproducibility, and reference data to recommended forearm and femur measurements at this time. Appropriate methods to account for growth delay when interpreting DXA results for children <5 yr are currently unknown. Reference data for children 0-5 yr at multiple skeletal sites are insufficient and are needed to enable interpretation of DXA measurements. Given the current scarcity of evidence in many areas, it is likely that these positions will change over time as new data become available.

Effects of weight-bearing activities on bone mineral content and density in children and adolescents: a meta-analysis

Osteoporosis and associated fractures are a major health concern in Western industrialized nations. Exercise during growth is suggested to oppose the involutional bone loss later in life by increasing peak bone mass. The primary aim of the present meta-analysis was to provide a robust estimate of the effect of weight-bearing activities (WBAs) on bone mineral content (BMC) and areal bone mineral density (aBMD), during childhood and adolescence. To locate relevant studies up to June 2012, computerized searches of multiple bibliographic databases and hand searches of key journals and reference lists were performed. Results were extracted by two independent reviewers. The quality of the included trials was assessed via the Physiotherapy Evidence Database (PEDro) score. The study group effect was defined as the difference between the standardized mean change for the treatment and control groups divided by the pooled pretest SD. From 109 potentially relevant studies, only 27 met the inclusion criteria. The analyzed training programs were capable of significantly increasing BMC and aBMD during growth. However, the weighted overall effect sizes (ESs) for changes in BMC (ES 0.17; 95% confidence interval [CI], 0.05-0.29; p < 0.05) and aBMD (ES 0.26; 95% CI, 0.02-0.49) were small. Stepwise backward regression revealed that more than one-third of the observed variance (r(2)  = 0.35) between subgroups of the BMC dataset could be explained by differences in the amount of habitual calcium intake per day (beta 0.54, p < 0.01) and the maturational stage (beta -0.28, p < 0.01) at baseline. No significant moderators were identified for aBMD, possibly due to the small number of trials investigating WBAs on aBMD. The results of this meta-analysis conclude that WBAs alongside high calcium intake provide a practical, relevant method to significantly improve BMC in prepubertal children, justifying the application of this exercise form as an osteoporosis prophylaxis in this stage of maturity.

A cluster randomized trial of a multi-level intervention, delivered by service staff, to increase physical activity of children attending center-based childcare

OBJECTIVE

To evaluate the impact of a multi-level intervention on the physical activity levels of 3-5 year old children attending center-based childcare services.

METHOD

The trial was conducted in New South Wales Australia in 2010 in 20 centers with 459 children. The intervention, included: fundamental movement skill sessions; structured activities; staff role modelling; limiting small screen recreation and sedentary time; and anactivity promoting physical environment. Control services continued with usual routines. Physical activity during care was assessed using pedometers at baseline and at six months after baseline. Intervention implementation was assessed via observation of staff physical activity practices and audits of service environment and policy.

RESULTS

Mean step counts at baseline and follow-up were 17.20 (CI 15.94-18.46) and 16.12 (CI 14.86-17.30) in the intervention group and 13.78 (CI 12.76-14.80) and 13.87 (CI 12.57-15.17) in the control group (p=0.12). Intervention services showed significantly greater increases in the total minutes that teachers led structured activities, relative to control group services (p=0.02).

CONCLUSION

The intervention showed no significant effect on child step counts per minute despite increasing time that staff delivered structured activity which is likely to be attributable to difficulties experienced by service staff in delivering a number of intervention components.

Physical activity is associated with bone geometry of premenarcheal girls in a dose-dependent manner

OBJECTIVE

To determine the relationship between habitual physical activity (PA) level and peripheral qualitative computed tomography-determined quantitative tibia characteristics of premenarcheal girls.

METHODS

Premenarcheal girls matched for age (10-13 years), bone age and maturity level were assigned into: a) low PA group (LPA, n=25), b) moderate PA group (MPA, n=17), and c) high PA group (HPA, n=18). Participants' daily dietary intake, tibia's geometry and serum levels of calcium and vitamin D were assessed.

RESULTS

Premenarcheal girls demonstrating HPA exhibited greater pericortical thickness, cross-sectional area (CSA) and bone mineral content (BMC) (p<.001) in cortical bone, greater BMC, volumetric bone density (vBMD) and polar stress strength index (SSIp) in trabecular bone (p<0.001-0.05) and greater total BMC (p<.05) and vBMD (p<.01) when compared to their physically inactive or moderately active counterparts. MPA exhibited greater values of cortical BMC (p<.01) and SSIp (p<.05) than LPA. Partial correlation analysis (adjusted for BMI) revealed modest associations between PA score and bone geometry parameters (r=0.36-0.49, p<.05) at 38% of tibia length.

CONCLUSIONS

Habitual PA affects geometry of both cortical and trabecular areas of a long bone of premenarcheal girls in a dose-dependent manner. Specifically, PA increases both the density and size of cortical bone but only the density of trabecular bone during preadolescence. Given the importance of peak bone mass for future fracture risk, high levels of PA during childhood could be a major target for public health interventions aimed at optimising bone health in prepubertal children when the greatest bone gains occur.

Effect of a school-based active play intervention on sedentary time and physical activity in preschool children

Early childhood is a critical time for promoting physical activity. Few studies have investigated the effect of interventions in this population. The aim of this study was to investigate the effect of a school-based active play intervention on preschool children's sedentary time and physical activity. Preschool children were recruited from randomly selected preschools. Schools were randomly assigned to an intervention or comparison group. One teacher per intervention school received training from active play professionals in the delivery of a 6-week active play programme. Comparison schools continued their usual practice. Children wore a uni-axial accelerometer for 7 days at baseline, immediately after and at 6-month post-intervention. No significant intervention effects were observed for sedentary time or physical activity. However, sex and hours spent at school were significant predictors of physical activity. Children who spent fewer hours (half-day children) at school were significantly more active than their full-day counterparts. Physical activity during the intervention classes was high even though neither daily physical activity nor sedentary time changed. Notably children who spent more time at preschool were less active suggesting that preschool was not as conducive to physical activity engagement as other environments.

Active video games as an exercise tool for children with cystic fibrosis

BACKGROUND

Active video games are used in many hospitals as exercise tools for children with cystic fibrosis. However, the exercise intensity associated with playing these games has not been examined in this population.

METHODS

Children with cystic fibrosis [n=30, aged 12.3 (2.6) years, 17 boys, BMI 17.7 (2.8) kg/m(2)] were recruited from outpatient clinics in Dublin hospitals. Age and gender matched control children were recruited from local schools. Oxygen consumption, metabolic equivalents (METs) calculated from resting V˙O2, and heart rate were measured while playing Nintendo Wii™ (Nintendo Co. Ltd., Tokyo, Japan) Sports Boxing and Nintendo Wii Fit Free Jogging using a portable indirect calorimeter (Oxycon Mobile).

RESULTS

Playing Wii Boxing resulted in light intensity activity (2.46METs) while playing Wii Fit Free Jogging resulted in moderate intensity physical activity (4.44METs). No significant difference was seen between groups in the energy cost of playing active video games.

CONCLUSION

Active video games are a useful source of light to moderate intensity physical activity in children with cystic fibrosis.

Can physical activity improve peak bone mass?

The pediatric origin of osteoporosis has led many investigators to focus on determining factors that influence bone gain during growth and methods for optimizing this gain. Bone responds to bone loading activities by increasing mass or size. Overall, pediatric studies have found a positive effect of bone loading on bone size and accrual, but the types of loads necessary for a bone response have only recently been investigated in human studies. Findings indicate that responses vary by sex, maturational status, and are site-specific. Estrogen status, body composition, and nutritional status also may influence the bone response to loading. Despite the complex interrelationships among these various factors, it is prudent to conclude that increased physical activity throughout life is likely to optimize bone health.

Objective assessment of levels and patterns of physical activity in preschool children

BACKGROUND

The aim of this study was to examine in detail levels and patterns of physical activity in preschool children and the effects of gender and BMI on this activity.

METHODS

Two hundred and fifty-three children aged 5 y participating in the Copenhagen Prospective Studies on Asthma in Childhood wore an accelerometer day and night over a 4-wk period. The main outcome measure was level of physical activity using the raw data. A secondary measure was time spent in moderate to vigorous physical activity (MVPA). A Fourier series analysis was applied to study in detail patterns over time.

RESULTS

Activity profiles throughout the year were unique for each sex, with boys being overall more active than girls except for winter months. Preschool children also showed distinct patterns of physical activity during weekdays as compared with weekends and were most active during weekdays. Preschool children in the highest tertile of BMI had a flat yearly activity profile and tended to be less active as compared with those in the lowest tertile.

CONCLUSION

Preschool children showed significant gender differences in physical activity, with distinct patterns throughout the year as well as between weekdays and weekends. A high BMI tended to be associated with lower levels of physical activity.

Monitoring activities of teenagers to comprehend their habits: study protocol for a mixed-methods cohort study

BACKGROUND

Efforts to increase physical activity in youth need to consider which activities are most likely to be sustained over time in order to promote lifelong participation in physical activity. The Monitoring Activities of Teenagers to Comprehend their Habits (MATCH) study is a prospective cohort study that uses quantitative and qualitative methods to develop new knowledge on the sustainability of specific physical activities.

METHODS/DESIGN

Eight hundred and forty-three grade 5 and 6 students recruited from 17 elementary schools in New Brunswick, Canada, are followed-up three times per year. At each survey cycle, participants complete self-report questionnaires in their classroom under the supervision of trained data collectors. A sub-sample of 24 physically active students is interviewed annually using a semi-structured interview protocol. Parents (or guardians) complete telephone administered questionnaires every two years, and a health and wellness school audit is completed for each school.

DISCUSSION

MATCH will provide a description of the patterns of participation in specific physical activities in youth, and enable identification of the determinants of maintenance, decline, and uptake of participation in each activity. These data will inform the development of interventions that take into account which activities are the most likely to be maintained and why activities are maintained or dropped.

Bone mineral density measured by a portable X-ray device agrees with dual-energy X-ray absorptiometry at forearm in preschool aged children

Dual-energy X-ray absorptiometry (DXA) measures of bone mineral density (BMD) are generally not feasible in fieldwork. The present study determined the agreement between BMD measured by DXA and portable peripheral DXA in preschool aged children. Fifty-seven children (4.2 ± 1.0 yr) had their nondominant distal forearm scanned using a peripheral DXA scanner (PIXI; GE Medical Systems Lunar, Madison, WI) at their daycare and a DXA (4500A Discovery Series; Hologic Inc., Bedford, MA) at our research clinic. Correlation analysis, one-way analysis of variance, and Bland-Altman plots were performed to examine the agreement between measurements. Data were also divided into tertiles for cross-classification analysis and calculation of kappa coefficients. Distal forearm BMD measured by PIXI was significantly correlated with DXA measures of total forearm BMD (r > 0.51; p < 0.001), proximal 1/3 BMD (r > 0.41; p < 0.001), mid-BMD (r > 0.37; p < 0.001), and ultradistal (UD) BMD (r > 0.57; p < 0.001). Cross-classification in the same or adjacent tertile between measures (UD forearm: 96.5%; UD radius: 94.4%; total forearm: 87.7%; total radius: 84.2%) resulted in weighted kappa coefficients of 0.46, 0.58, 0.42, and 0.43, respectively. Bland-Altman plots further clarified these agreements as all had low bias (UD forearm: bias = 0.003 ± 0.002; UD radius: -0.015 ± 0.021; total forearm: -0.062 ± 0.027; total radius: -0.077 ± 0.026). These results demonstrate that portable DXA measures of forearm BMD agree moderately with DXA.

Bone mass following physical activity in young years: a mean 39-year prospective controlled study in men

This is a study on exercise-associated bone mineral density (BMD) which in men is maintained three decades after cessation of sports. In this prospective controlled cohort study active athletes had a BMD Z-score of 1.0 and after 39 years 0.5 to 1.2 depending on the measured region), using the same single-photon absorptiometry device, dual X-ray absorptiometry (DXA), and peripheral computed tomography (pQCT).

INTRODUCTION

The aims of this study were to prospectively evaluate BMD changes in male athletes from activity into long-term retirement and to simultaneously evaluate other bone traits.

METHODS

Bone mineral density (grams per square centimeter) was measured in 46 male athletes with a mean age of 22 years (range, 15-40) by using the same single-photon absorptiometry device, both at active career and a mean of 39 years (range, 38-40) later when they had long-term retired. At follow-up, BMD was also evaluated by DXA and pQCT. Twenty-four non-athletic males of similar age served as controls. Between-group differences are presented as means with 95% confidence intervals.

RESULTS

The active athletes (baseline) had a BMD Z-score of 1.0 (0.7, 1.4) in the femoral condyles. The retired athletes (follow-up) had a BMD Z-score of 0.5 to 1.2 depending on the measuring technique and the measured region. The tibial cortical area Z-score at follow-up was 0.8 (0.5, 1.2) and the tibial strength index Z-score 0.7 (0.4, 1.0). There were no changes in BMD Z-scores from activity to retirement, neither when estimated by the same device in different regions [∆ Z-score -0.3 (-0.8, 0.2)] nor in the same region with different devices [∆ Z-score 0.0 (-0.4, 0.4)]. The benefits remained after adjustments for anthropometrics and lifestyle. No correlation was seen with years since retirement.

CONCLUSIONS

Exercise-associated high BMD in young years seems, in men, to be maintained three decades after cessation of high-level physical activity.

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.

Body size and pubertal development explain ethnic differences in structural geometry at the femur in Asian, Hispanic, and white early adolescent girls living in the U.S

Variation in structural geometry is present in adulthood, but when this variation arises and what influences this variation prior to adulthood remains poorly understood. Ethnicity is commonly the focus of research of skeletal integrity and appears to explain some of the variation in quantification of bone tissue. However, why ethnicity explains variation in skeletal integrity is unclear.

METHODS

Here we examine predictors of bone cross sectional area (CSA) and section modulus (Z), measured using dual-energy X-ray absorptiometry (DXA) and the Advanced Hip Analysis (AHA) program at the narrow neck of the femur in adolescent (9-14 years) girls (n=479) living in the United States who were classified as Asian, Hispanic, or white if the subject was 75% of a given group based on parental reported ethnicity. Protocols for measuring height and weight follow standardized procedures. Total body lean mass (LM) and total body fat mass (FM) were quantified in kilograms using DXA. Total dietary and total dairy calcium intakes from the previous month were estimated by the use of an electronic semi-quantitative food frequency questionnaire (eFFQ). Physical activity was estimated for the previous year by a validated self-administered modifiable activity questionnaire for adolescents with energy expenditure calculated from the metabolic equivalent (MET) values from the Compendium of Physical Activities. Multiple regression models were developed to predict CSA and Z.

RESULTS

Age, time from menarche, total body lean mass (LM), total body fat mass (FM), height, total calcium, and total dairy calcium all shared a significant (p<0.05), positive relationship with CSA. Age, time from menarche, LM, FM, and height shared significant (p<0.05), positive relationships with Z. For both CSA and Z, LM was the most important covariate. Physical activity was not a significant predictor of geometry at the femoral neck (p≥0.339), even after removing LM as a covariate. After adjusting for covariates, ethnicity was not a significant predictor in regression models for CSA and Z.

CONCLUSION

Variability in bone geometry at the narrow neck of the femur is best explained by body size and pubertal maturation. After controlling for these covariates there were no differences in bone geometry between ethnic groups.

A cross-sectional study of the relationship between cortical bone and high-impact activity in young adult males and females

CONTEXT

The factors that govern skeletal responses to physical activity remain poorly understood.

OBJECTIVE

The aim of this study was to investigate whether gender or fat mass influences relationships between cortical bone and physical activity, after partitioning accelerometer outputs into low (0.5-2.1 g), medium (2.1-4.2 g), or high (>4.2 g) impacts, where g represents gravitational force.

DESIGN/SETTING

We conducted a cross-sectional analysis in participants from the Avon Longitudinal Study of Parents and Children.

PARTICIPANTS

We studied 675 adolescents (272 boys; mean age, 17.7 yr).

OUTCOME MEASURES

We measured cortical bone parameters from peripheral quantitative computed tomography scans of the mid-tibia, adjusted for height, fat mass, and lean mass.

RESULTS

High-impact activity was positively associated with periosteal circumference (PC) in males but not females [coefficients (95% confidence intervals), 0.054 (0.007, 0.100) and 0.07 (-0.028, 0.041), respectively; showing sd change per doubling in activity]. There was also weak evidence that medium impacts were positively related to PC in males but not females (P=0.03 for gender interaction). On stratifying by fat mass, the positive relationship between high-impact activity and PC was greatest in those with the highest fat mass [high impact vs. PC in males, 0.01 (-0.064, 0.085), 0.045 (-0.040, 0.131), 0.098 (0.012, 0.185), for lower, middle, and upper fat tertiles, respectively; high impact vs. PC in females, -0.041 (-0.101, 0.020), -0.028 (-0.077, 0.022), 0.082 (0.015, 0.148), P=0.01 for fat mass interaction]. Similar findings were observed for strength parameters, cross-sectional moment of inertia, and strength-strain index.

CONCLUSIONS

In late adolescence, associations between high-impact activity and PC are attenuated by female gender and low body fat, suggesting that the skeletal response to high-impact activity is particularly reduced in young women with low fat mass.

Habitual levels of high, but not moderate or low, impact activity are positively related to hip BMD and geometry: results from a population-based study of adolescents

Whether a certain level of impact needs to be exceeded for physical activity (PA) to benefit bone accrual is currently unclear. To examine this question, we performed a cross-sectional analysis between PA and hip BMD in 724 adolescents (292 boys, mean 17.7 years) from the Avon Longitudinal Study of Parents and Children (ALSPAC), partitioning outputs from a Newtest accelerometer into six different impact bands. Counts within 2.1 to 3.1g, 3.1 to 4.2g, 4.2 to 5.1g, and >5.1g bands were positively related to femoral neck (FN) BMD, in boys and girls combined, in our minimally adjusted model including age, height, and sex (0.5-1.1g: beta = -0.007, p = 0.8; 1.1-2.1g: beta = 0.003, p = 0.9; 2.1-3.1g: beta = 0.042, p = 0.08; 3.1-4.2g: beta = 0.058, p = 0.009; 4.2-5.1g: beta = 0.070, p = 0.001; >5.1g: beta = 0.080, p < 0.001) (beta = SD change per doubling in activity). Similar positive relationships were observed between high-impact bands and BMD at other hip sites (ward's triangle, total hip), hip structure indices derived by hip structural analysis of dual-energy X-ray absorptiometry (DXA) scans (FN width, cross-sectional area, cortical thickness), and predicted strength (cross-sectional moment of inertia). In analyses where adjacent bands were combined and then adjusted for other impacts, high impacts (>4.2g) were positively related to FN BMD, whereas, if anything, moderate (2.1-4.2g) and low impacts (0.5-2.1g) were inversely related (low: beta = -0.052, p = 0.2; medium: beta = -0.058, p = 0.2; high: beta = 0.137, p < 0.001). Though slightly attenuated, the positive association between PA and FN BMD, confined to high impacts, was still observed after adjustment for fat mass, lean mass, and socioeconomic position (high: beta = 0.096, p = 0.016). These results suggest that PA associated with impacts >4.2g, such as jumping and running (which further studies suggested requires speeds >10 km/h) is positively related to hip BMD and structure in adolescents, whereas moderate impact activity (eg, jogging) is of little benefit. Hence, PA may only strengthen lower limb bones in adolescents, and possibly adults, if this comprises high-impact activity.

Role of calcium during pregnancy: maternal and fetal needs

Although the demand for additional calcium during pregnancy is recognized, the dietary reference intake for calcium was lowered for pregnant women in 1997 to amounts recommended for nonpregnant women (1,000 mg/day), and recently (November 2010) the Institute of Medicine report upheld the 1997 recommendation. It has been frequently reported that women of childbearing age do not consume the dietary reference intake for calcium and that calcium intake in the United States varies among ethnic groups. Women who chronically consume suboptimal amounts of calcium (<500 mg/day) may be at risk for increased bone loss during pregnancy. Women who begin pregnancy with adequate intake may not need additional calcium, but women with suboptimal intakes (<500 mg) may need additional amounts to meet both maternal and fetal bone requirements. The objective of this review is to elucidate the changes in calcium metabolism that occur during pregnancy as well as the effect of maternal calcium intake on both maternal and fetal outcomes.

Systematic review of physical activity and health in the early years (aged 0–4 years)

The early years represent a critical period for promoting physical activity. However, the amount of physical activity needed for healthy growth and development is not clear. Using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework, we aimed to present the best available evidence to determine the relationship between physical activity and measures of adiposity, bone and skeletal health, motor skill development, psychosocial health, cognitive development, and cardiometabolic health indicators in infants (1 month – 1 year), toddlers (1.1–3.0 years), and preschoolers (3.1–4.9 years). Online databases, personal libraries, and government documents were searched for relevant studies. Twenty-two articles, representing 18 unique studies and 12 742 enrolled participants, met inclusion criteria. The health indicators of interest were adiposity (n = 11), bone and skeletal health (n = 2), motor development (n = 4), psychosocial health (n = 3), cognitive development (n = 1), and cardiometabolic health indicators (n = 3); these indicators were pre-specified by an expert panel. Five unique studies involved infants, 2 involved toddlers, and 11 involved preschoolers. In infants, there was low- to moderate-quality evidence to suggest that increased or higher physical activity was positively associated with improved measures of adiposity, motor skill development, and cognitive development. In toddlers, there was moderate-quality evidence to suggest that increased or higher physical activity was positively associated with bone and skeletal health. In preschoolers, there was low- to high-quality evidence on the relationship between increased or higher physical activity and improved measures of adiposity, motor skill development, psychosocial health, and cardiometabolic health indicators. There was no serious inconsistency in any of the studies reviewed. This evidence can help to inform public health guidelines. (PROSPERO registration: CRD42011001243)

Bone mechanotransduction may require augmentation in order to strengthen the senescent skeleton

Physical exercise is thought to hold promise as a non-invasive countermeasure against skeletal fragility arising from post-menopausal and age-related osteoporosis. Importantly, mechanical loading and exercise are capable of increasing bone size via periosteal expansion, which by far, is the most effective means of strengthening the structure of a given bone. The focus of this review was to therefore explore whether exercise has the potential to increase periosteal modeling and bone size in the senescent skeleton. A survey of exercise trials in humans suggests that exercise interventions that enhance periosteal modeling in the young skeleton fail to do the same in the elderly skeleton. Underlying this ineffectiveness, in vitro studies indicate that aging lowers basal levels of cell function and degrades bone mechanotransduction at a variety of levels from altered second messenger signaling to gene expression driving proliferation and/or differentiation. Given these age-related alterations, the ultimate efficacy of an exercise intervention may depend upon concurrent supplementation that directly address deficits in signaling and/or cell function. In this context, in vivo animal models of mechanical loading that simulate the muted periosteal adaptation in the elderly hold potential to examine the efficacy of countermeasures. Preliminary in vivo experiments suggest that pharmacologically counteracting age-related deficits in cellular function can restore exercise induced periosteal modeling in the senescent skeleton to levels observed in young animals. If the safety and efficacy of this strategy were to be confirmed for human use, it would enable the utilization of exercise as a viable countermeasure against skeletal fragility at senescence.

Physical activity as a strategy to reduce the risk of osteoporosis and fragility fractures

Childhood and adolescence are critical periods for the skeleton. Mechanical load has then been shown to be one of the best stimuli to enhance not only bone mass, but also structural skeletal adaptations, as both contributing to bone strength. Exercise prescription also includes a window of opportunity to improve bone strength in the late pre- and early peri-pubertal period. There is some evidence supporting the notion that skeletal gains obtained by mechanical load during growth are maintained at advanced age despite a reduction of physical activity in adulthood. The fact that former male athletes have a lower fracture risk than expected in their later years does not oppose the view that physical activity during growth and adolescence is important and it should be supported as one feasible strategy to reduce the future incidence of fragility fractures.

Prevention of nutritional rickets in Nigerian children with dietary calcium supplementation

Nutritional rickets in Nigerian children usually results from dietary calcium insufficiency. Typical dietary calcium intakes in African children are about 200mg daily (approximately 20-28% of US RDAs for age). We sought to determine if rickets could be prevented with supplemental calcium or with an indigenous food rich in calcium. We enrolled Nigerian children aged 12 to 18months from three urban communities. Two communities were assigned calcium, either as calcium carbonate (400mg) or ground fish (529±109mg) daily, while children in all three communities received vitamin A (2500IU) daily as placebo. Serum markers of mineral homeostasis and forearm bone density (pDEXA) were measured and radiographs were obtained at enrollment and after 18months of supplementation. The overall prevalence of radiographic rickets at baseline was 1.2% and of vitamin D deficiency [serum 25(OH)D<12ng/ml] 5.4%. Of 647 children enrolled, 390 completed the 18-month follow-up. Rickets developed in 1, 1, and 2 children assigned to the calcium tablet, ground fish, and control groups, respectively (approximate incidence 6.4/1000 children/year between 1 and 3years of age). Children who developed rickets in the calcium-supplemented groups had less than 50% adherence. Compared with the group that received no calcium supplementation, the groups that received calcium had a greater increase in areal bone density of the distal and proximal 1/3 radius and ulna over time (P<0.04). We conclude that calcium supplementation increased areal bone density at the radius and ulna, but a larger sample size would be required to determine its effect on the incidence of rickets.

Accelerometer-derived physical activity levels of preschoolers: a meta-analysis

OBJECTIVES

This study synthesized the published estimates of daily moderate-to-vigorous physical activity (MVPAd(-1)) of preschooler-age children (3-5 years).

DESIGN

Meta-analysis of previously published studies reporting accelerometer-derived estimates of daily MVPA of preschoolers.

METHODS

A comprehensive literature review was conducted to identify studies published by March 2010 that reported daily minutes of accelerometer-derived MVPA in preschool-age children (3-5 years). Random effects point estimates and 95% confidence intervals (95% CIs) were calculated based on study weighted means and standard deviations of raw accelerometer counts per minute (cpm) and reported minutes of MVPA and/or percentage of time spent in MVPAd(-1).

RESULTS

29 articles representing 6309 preschoolers were included. Overall, preschoolers engaged in 42.8 min (95% CI 28.9-56.8) of MVPAd(-1), and 54.4 min (95% CI 29.9-78.9) and 45.4 min (95% CI 25.2-65.6) for boys and girls separately. This translated into approximately 5.5% (95% CI 3.7-7.2%) of time spent in MVPAd(-1), and 7.1% (95% CI 3.9-10.3%) for boys and 6.3% (95% CI 3.9-8.7%) for girls. Studies (76%) using ActiGraph accelerometers reported an average of 714 cpm (95% CI 678-751), with boys and girls having 783 cpm (95% CI 753-813) and 696 cpm (95% CI 665-727), respectively.

CONCLUSIONS

Interpretation of accelerometer-derived MVPA is confounded by differences in cutpoints applied within a study. Great care, therefore, should be taken when interpreting the activity levels of preschoolers to inform policy decisions, such as the development of physical activity guidelines. Hence, considerable attention is required to unify accelerometer-derived MVPA so that unbiased comparisons across studies can be made.

Critical narrative review to identify educational strategies promoting physical activity in preschool

The aim of this narrative review is critically to evaluate educational strategies promoting physical activity that are used in the preschool setting in the context of obesity prevention programmes. Literature search was conducted between April and August 2010 in English and German databases (PubMED, PsychINFO, PSYNDEX, ERIC, FIS Bildung). Outcomes considered were time and intensity of physical activity, motor skills or measures of body composition. A total of 19 studies were included. Ten studies added physical activity lessons into their curriculum, one study provided more time for free play, eight studies focused on the social and play environment. Studies reporting positive outcomes implemented physical activity sessions that lasted at least 30 min d(-1). Several studies showed that children are most active in the first 10-15 min. The existence or installation of playground markings or fixed play equipment had no effect, whereas the presence or addition of portable play equipment was positively correlated with moderate-to-vigorous physical activity. Teacher training may be a key element for successful interventions. To overcome time constraints, a suggested solution is to integrate physical activity into daily routines and other areas of the preschool curriculum.

Longitudinal effects of fat and lean mass on bone accrual in infants

There are conflicting reports on the influence of lean and fat mass on bone accrual during childhood. No infant's studies have been reported that describe the influence of changes in body composition with changes in bone accrual during the first year of life. The objective of this research was to test the hypothesis that greater gains in lean mass will have a positive effect on bone mineral content (BMC) accrual, while greater gains in fat mass will have a negative effect on BMC accrual in infants. Longitudinal data from 3 previous infant studies were used. Linear mixed models, adjusting for age, sex, dietary calcium, and length were used to investigate longitudinal and cross-sectional associations between total body BMC and lean and fat mass in the individual studies and in a combined analysis. In both individual and combined analyses, we found that lean and fat mass were positively associated with whole body BMC accrual (all, P<0.001). The cross-sectional association of BMC and dietary calcium was negative in one study (P<0.05). No differences in BMC change between sexes were observed in three studies. Our results showed positive cross-sectional and longitudinal associations between total body BMC and lean mass in infants. In contradiction to our hypothesis for fat mass, we found a positive cross-sectional and longitudinal association between total body BMC and fat mass in infants.

Bone mineral density changes after physical training and calcium intake in students with attention deficit and hyper activity disorders

In this study we investigate the effects of weight bearing exercise and calcium intake on bone mineral density (BMD) of students with attention deficit and hyper activity (ADHD) disorder. For this reason 54 male students with ADHD (age 8-12 years old) were assigned to four groups with no differences in age, BMD, calcium intake, and physical activity: exercise groups with or without calcium supplementation (Ex+Ca+ and Ex+Ca-) and non-exercise groups with or without calcium supplementation (Ex-Ca+ and Ex-Ca-). The intervention involved 50 min of weight bearing exercise performed 3 sessions a week and/or the addition of dietary calcium rich food using enriched cow milk with vitamin D containing 250 mg calcium per serving, over 9 months. Paired-samples t-test, one way ANOVA analysis, and Tukey tests were used to determine the main and combined effects of training and calcium on BMD. All groups showed greater femoral neck BMD after 9 months. The increase in femoral neck BMD was significantly different between all groups (p < 0.05). Ex+Ca+ group has greater increase in BMD than other groups. Apparently, the effect of training was greater than calcium intake (p < 0.05). These results help to provide more evidence for public health organizations to deal with both exercise and nutrition issues in children with ADHD disorder for the achievement of peak BMD.

Physical activity in child-care centers: do teachers hold the key to the playground?

Many (56%) US children aged 3-5 years are in center-based childcare and are not obtaining recommended levels of physical activity. In order to determine what child-care teachers/providers perceived as benefits and barriers to children's physical activity in child-care centers, we conducted nine focus groups and 13 one-on-one interviews with 49 child-care teachers/providers in Cincinnati, OH. Participants noted physical and socio-emotional benefits of physical activity particular to preschoolers (e.g. gross motor skill development, self-confidence after mastery of new skills and improved mood, attention and napping after exercise) but also noted several barriers including their own personal attitudes (e.g. low self-efficacy) and preferences to avoid the outdoors (e.g. don't like hot/cold weather, getting dirty, chaos of playground). Because individual teachers determine daily schedules and ultimately make the decision whether to take the children outdoors, they serve as gatekeepers to the playground. Participants discussed a spectrum of roles on the playground, from facilitator to chaperone to physical activity inhibitor. These findings suggest that children could have very different gross motor experiences even within the same facility (with presumably the same environment and policies), based on the beliefs, creativity and level of engagement of their teacher.

Physical activity, calcium intake and childhood bone mineral: a population-based cross-sectional study

In a free-living cohort of 4-year old children, mean daily time in moderate-vigorous physical activity and daily calcium intake at 3 years, were positively related to hip bone size and density. Relationships between physical activity and bone indices were stronger when calcium intake was above compared with below median (966 mg/day).

INTRODUCTION

We examined the cross-sectional relationships between childhood physical activity, dietary calcium intake and bone size and density.

METHODS

Children aged 4 years were recruited from the Southampton Women's Survey. They underwent measurement of bone mass by DXA (Hologic Discovery). Physical activity was assessed by accelerometry (Actiheart, Cambridge Neurotechnology Ltd, Cambridge, UK) for seven continuous days.

RESULTS

Four hundred twenty-two children (212 boys) participated. In a cross-sectional analysis, after adjusting for gender, daily mean time(minutes per day) spent in moderate to very vigorous activity (MVPA) was positively related to hip BA (R(2) = 3%, p < 0.001), BMC (R(2) = 4%, p < 0.001), aBMD (R (2) = 3%, p = 0.001) and estimated vBMD (R(2) = 2%, p = 0.01), but not height (r (s) = 0.04, p = 0.42) or weight (r(s) = 0.01, p = 0.76). Mean daily calcium intake (assessed at 3 years old) positively predicted bone indices in those with a calcium intake below the median (966 mg/day), but there was a much attenuated relationship in those above this. These associations persisted after inclusion of total energy, protein and phosphorus in multivariate models. The relationships between MVPA and bone indices were stronger in children with calcium intakes above the median. Thus, for aBMD, the variance explained by MVPA when daily calcium intake was below the median was 2% (p = 0.1) and above median was 6% (p = 0.001).

CONCLUSIONS

These results support the notion that adequate calcium intake may be required for optimal action of physical activity on bone development and that improving levels of physical activity and calcium intake in childhood may help to optimise accrual of bone mass.

Variation in childhood skeletal robustness is an important determinant of cortical area in young adults

A better understanding of bone growth will benefit efforts to reduce fracture incidence, because variation in elderly bone traits is determined primarily by adulthood. The natural variation in robustness was used as a model to understand how variable growth patterns define adult bone morphology. Longitudinally acquired hand radiographs of 29 boys and 30 girls were obtained from the Bolton-Brush study for 6 time points spanning 8 to 18 years of age. Segregating individuals into tertiles based on robustness revealed that the biological activity underlying bone growth varied significantly with the natural variation in robustness. For boys, slender metacarpals used an osteoblast-dependent growth pattern to establish function, whereas robust metacarpals used an osteoclast-dependent growth pattern. In contrast, differences in biological activity between girls with slender and robust metacarpals were largely based on the age at which the marrow surface changed from expansion to infilling. Importantly, cortical area for slender metacarpals was as much as 19.7% and 32.2% lower than robust metacarpals for boys and girls, respectively, indicating that robustness was a major determinant of adult cortical area. Finally, after accounting for robustness and body weight effects, we found that the inter-individual variation in cortical area was established as early as 8 years of age. While variation in the amount of bone acquired during growth has primarily been attributed to factors like nutrition, exercise, and genetic background, we showed that the natural variation in robustness was also a major determinant of cortical area, which is an important determinant of bone mass. This predictable relationship between robustness and cortical area should be incorporated into clinical diagnostic measures and experimental studies.

Skeletal health of children and adolescents with inflammatory bowel disease

Current evidence points to suboptimal bone health in children and adolescents with inflammatory bowel disease (IBD) when compared with their healthy peers. This compromise is evident from diagnosis. The clinical consequences and long-term outcome of this finding are still unknown. The mechanism of suboptimal bone health in children and adolescents with IBD lays mainly in reduced bone formation, but also reduced bone resorption, processes necessary for bone growth. Factors contributing to this derangement are inflammation, delayed growth and puberty, lean mass deficits, and use of glucocorticoids. We recognize that evidence is sparse on the topic of bone health in children and adolescents with IBD. In this clinical guideline, based on current evidence, we provide recommendations on screening and monitoring bone health in children and adolescents with IBD, including modalities to achieve this and their limitations; monitoring of parameters of growth, pubertal development, and reasons for concern; evaluation of vitamin D status and vitamin D and calcium intake; exercise; and nutritional support. We also report on the current evidence of the effect of biologics on bone health in children and adolescents with IBD, as well as the role of bone active medications such as bisphosphonates. Finally, we summarize the existing numerous gaps in knowledge and potential subjects for future research endeavors.

Habitual levels of vigorous, but not moderate or light, physical activity is positively related to cortical bone mass in adolescents

CONTEXT

The intensity of habitual physical activity (PA) needed to affect skeletal development in childhood is currently unclear.

OBJECTIVE

To examine associations between light PA, moderate PA, and vigorous PA (as assessed by accelerometry), and tibial cortical bone mass (BMC(C)) as measured by peripheral quantitative computed tomography.

DESIGN/SETTING

Cross-sectional analysis based on the Avon Longitudinal Study of Parents and Children.

PARTICIPANTS

A total of 1748 boys and girls (mean age 15.5 yr) participated in the study.

OUTCOME MEASURES

We measured BMC(C), cortical bone mineral density, periosteal circumference, and endosteal circumference by tibial peripheral quantitative computed tomography.

RESULTS

Multivariable models, adjusted for height and other activity levels, indicated vigorous PA was positively related to BMC(C) (P = 0.0001). There was little evidence of a relationship with light PA or moderate PA (both P ≥ 0.7). In path analyses, the relationship between vigorous PA and BMC(C) [0.082 (95% confidence interval [CI]: 0.037, 0.128), P = 0.0004] (SD change per doubling of vigorous PA) was minimally attenuated by adjusting for body composition [0.070 (95% CI: 0.026, 0.115), P = 0.002]. In analyses adjusted for body composition, the relationship between vigorous PA and BMC(C) was explained by the periosteal circumference pathway [0.043 (95% CI: 0.004, 0.082), P = 0.03] and the endosteal circumference adjusted for periosteal circumference pathway [0.031 (95% CI: 0.011, 0.050), P = 0.002], while there was little contribution from the cortical bone mineral density pathway (P = 0.3).

CONCLUSIONS

Vigorous day-to-day PA is associated with indices of BMC(C) and geometry in adolescents, whereas light or moderate PA has no detectable association. Therefore, promoting PA in childhood is unlikely to benefit skeletal development unless high-impact activities are also increased.

Determinants of bone mineral content and bone area in Indian preschool children

The objective of this study was to examine the lifestyle factors that influence total body bone mineral content (TB BMC) and total body bone area (TB BA) in Indian preschool children. TB BMC and TB BA were measured by dual-energy X-ray absorptiometry (Lunar DPX PRO) in 71 apparently healthy children aged 2-3 years. A fasting blood sample was analyzed for serum concentrations of ionized calcium (iCa), intact parathyroid hormone (iPTH), phosphorus (iP) and 25-hydroxyvitamin D(3) (25 OHD). Dietary intake of energy, protein, calcium and phosphorus was estimated from a 3-day diet recall. The daily physical activity and sunlight exposure were recorded by a questionnaire. The study children were shorter than their age-gender matched WHO counterparts with a mean height for age Z score of -1.3 ± 1.5. The mean dietary intake of calcium was 46% of the Indian recommended dietary intakes (RDI). Seventy-three percent of children had low iCa concentrations, and 57% were deficient in vitamin D. Generalized linear model analysis revealed that height, lean body mass, weight, activity, sunlight exposure in minutes and dietary intakes of calcium, zinc and iron were the significantly influencing factors (p < 0.05) of TB BMC and TB BA. In conclusion, attaining optimal height for age, achieving the goals of overall nutrition with adequate calcium, iron and zinc intakes as well as adequate physical activity and sunlight exposure play an important role in achieving better TB BMC and TB BA in preschool children.

Associations of physical activity duration, frequency, and load with volumetric BMD, geometry, and bone strength in young girls

SUMMARY

More efficacious physical activity (PA) prescriptions for optimal bone development are needed. This study showed that PA duration, frequency, and load were all independently associated with bone parameters in young girls. Increased PA duration, frequency, and load are all important osteogenic stimuli that should be incorporated into future PA interventions.

INTRODUCTION

This study evaluated the associations of physical activity (PA) duration, frequency, load, and their interaction (total PA score = duration × frequency × load) with volumetric bone mineral density, geometry, and indices of bone strength in young girls.

METHODS

Four hundred sixty-five girls (aged 8-13 years) completed a past year physical activity questionnaire (PYPAQ) which inquires about the frequency (days per week) and duration (average minutes per session) of leisure-time PA and sports. Load (peak strain score) values were assigned to each activity based on ground reaction forces. Peripheral quantitative computed tomography was used to assess bone parameters at metaphyseal and diaphyseal sites of the femur and tibia of the non-dominant leg.

RESULTS

Correlations across all skeletal sites between PA duration, frequency, load and periosteal circumference (PC), bone strength index (BSI), and strength-strain index (SSI) were significant (p ≤ 0.05), although low (0.10-0.17). A 2.7-3.7% greater PC across all skeletal sites was associated with a high compared to a low PYPAQ score. Also, a high PYPAQ score was associated with greater BSI (6.5-8.7%) at metaphyseal sites and SSI (7.5-8.1%) at diaphyseal sites of the femur and tibia. The effect of a low PYPAQ score on bone geometric parameters and strength was greater than a high PYPAQ score.

CONCLUSIONS

PA duration, frequency, and load were all associated with bone geometry and strength, although their independent influences were modest and site specific. Low levels of PA may compromise bone development whereas high levels have only a small benefit over more average levels.

Maternal vitamin D status affects bone growth in early childhood--a prospective cohort study

In this prospective study, 87 children were followed up from birth to 14 months with data on maternal vitamin D status during the pregnancy. Postnatal vitamin D supplementation improved vitamin D status but only partly eliminated the differences in bone variables induced by maternal vitamin D status during the fetal period.

INTRODUCTION

Intrauterine nutritional deficits may have permanent consequences despite improved nutritional status postnatally. We evaluated the role of prenatal and postnatal vitamin D status on bone parameters in early infancy.

METHODS

Eighty-seven children were followed from birth to 14 months. Background data were collected with a questionnaire and a 3-day food record. At 14 months bone variables were measured with peripheral computed tomography (pQCT) from the left tibia. Serum 25-OHD and bone turnover markers were determined. Findings were compared with maternal vitamin D status during pregnancy.

RESULTS

The children were divided into two groups based on vitamin D status during pregnancy. Despite discrepant S-25-OHD at baseline (median 36.3 vs. 52.5 nmol/l, p < 0.001), the values at 14 months were similar (63 vs. 66 nmol/l, p = 0.58) in Low D and High D. Serum 25-OHD increased more in Low D (p < 0.001) despite similar total intake of vitamin D (mean 12.3 μg/day). In Low D, tibial bone mineral content (BMC) was lower at birth but BMC gain was greater (multivariate analysis of variance [MANOVA]; p = 0.032) resulting in similar BMC at 14 months in the two groups. In High D, tibial total bone cross-sectional area was higher at baseline; the difference persisted at 14 months (MANOVA; p = 0.068). Bone mineral density (BMD) and ΔBMD were similar in the two groups.

CONCLUSIONS

Postnatal vitamin D supplementation improved vitamin D status but only partly eliminated the differences in bone variables induced by maternal vitamin D status during the fetal period. Further attention should be paid to improving vitamin D status during pregnancy.

Pediatric inflammatory bowel disease and bone health

Childhood and adolescence are important periods for bone development. Any disease that affects bone health has the potential to affect the bones not only in the short term but also later in life. Bone health abnormalities in patients with inflammatory bowel disease are being increasingly recognized. Screening the at-risk patient is important so that appropriate treatments can be instituted. Treatment options are limited to vitamin D and calcium supplementation, control of underlying disease activity, and appropriate physical activity. The role of bisphosphonates in these patients needs to be better studied, and treatment with bisphosphonates may be considered for some patients in consultation with a bone health expert.

Calcium and vitamin-D supplementation on bone structural properties in peripubertal female identical twins: a randomised controlled trial

A randomised controlled trial was used in assessing the impact of 6 months of daily calcium and vitamin-D supplementation on trabecular and cortical bone acquisition at distal tibial and radial sites using peripheral quantitative computed tomography (pQCT). Daily supplementation was associated with increased bone density and bone strength at the distal tibia and radius.

INTRODUCTION

pQCT has not been used to assess bone responses to calcium and vitamin-D supplementation on peripubertal children. This randomised controlled trial aimed to assess the impact of a 6-month daily calcium and vitamin-D supplementation on trabecular and cortical bone acquisition at distal tibial and radial sites using pQCT.

METHODS

Twenty pairs of peripubertal female identical twins, aged 9 to 13 years, were randomly assigned to receive either 800 mg of calcium and 400 IU of vitamin D3, or a matched placebo. Bone structural properties at the distal tibia and distal radius were acquired at baseline and 6 months.

RESULTS

The calcium-supplemented group showed greater gains in trabecular density, trabecular area and strength strain index at the 4% of distal tibial and radial sites compared with the placebo group (p=0.001). Greater gains in cortical area at the 38% and 66% of tibial sites were also found in twins receiving the calcium supplement (p=0.001).

CONCLUSIONS

Daily supplementation for a period of 6 months was associated with increased trabecular area, trabecular density and strength strain index at the ultra-distal tibia and radius and increased cortical area at tibial mid-shaft.

A pilot randomized controlled trial of oral calcium and vitamin D supplementation using fortified laddoos in underprivileged Indian toddlers

BACKGROUND/OBJECTIVES

Low habitual dietary calcium intake and vitamin D deficiency are common among Indian children. Using 'laddoo', an Indian snack, as a vehicle for administering calcium and vitamin D supplements, a randomized double-blind controlled trial was conducted for 12 months to assess its efficacy on total body less head (TBLH) bone mineral content (BMC) in underprivileged toddlers.

SUBJECTS/METHODS

A total of 60 toddlers (mean age 2.7±0.52 years, boys=31) were randomized to two groups, (i) study group receiving one calcium fortified laddoo (cereal-legume snack) containing 405 mg calcium per day and (ii) control receiving a non-fortified laddoo, containing 156 mg of indigenous calcium. Both groups also received a laddoo fortified with 30,000 IU of vitamin D(3) per month. Outcome measures included TBLH bone area (BA) and TBLH BMC by GE-Lunar DPX Pro Pencil Beam Dual-Energy X-ray absorptiometry.

RESULTS

At baseline, mean energy, protein and calcium intakes were 71, 72 and 47% of Indian Recommended Dietary allowances. In all, 87 and 83% toddlers were hypocalcaemia and vitamin D deficient, respectively. Mean TBLH BMC was 289.5±45.8 g. Post supplementation, mean TBLH BMC of study group showed a significantly greater (P<0.01) increase of 35% as against 28% in controls and the difference remained significant after adjusting for vitamin D status, calcium intake, height and TBLH BA.

CONCLUSIONS

Daily supplementation with calcium fortified laddoo, and monthly vitamin D supplement resulted in a significant increase in TBLH BMC of underprivileged toddlers. We believe that such strategies have the potential of addressing nutritional problems in developing countries.

Growth in childhood predicts hip fracture risk in later life

The incidence of hip fracture was estimated in 6,370 women born in Helsinki between 1934 and 1944. Women in the lowest quarter of adiposity gain had an 8.2-fold increase in hip fracture risk compared with those in the highest quarter (p < 0.001). These data point to a relationship between childhood growth and fracture risk during later life.

INTRODUCTION

Previous findings show that discordance between childhood increase in height and weight is associated with an increased risk of osteoporotic fractures during later life.

METHODS

We studied 6,370 women born in Helsinki between 1934 and 1944. Each woman's birth weight and length at birth was recorded, as well as her height and weight through childhood. We identified the occurrence of hip fracture through the National Finnish Hospital discharge register.

RESULTS

There were 49 hip fractures in the 6,370 women over 187,238 person-years of follow-up. Hip fracture was associated with increasing Z-scores for height between 1 and 12 years, not matched by a corresponding increase in weight. Therefore, reduction in the Z-score for body mass index was associated with increased risk of hip fracture. Women in the lowest quarter of change in Z-scores for body mass index had an 8.2-fold increase in hip fracture risk (95% CI 1.9 to 35), compared with those in the highest quarter (p < 0.001).

CONCLUSION

Thinness in childhood is a risk factor for hip fracture in later life. This could be a direct effect of low fat mass on bone mineralization, or represent the influence of altered timing of pubertal maturation.

Prevalence and burden of pediatric-onset systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic, multisystem autoimmune disease with a highly variable clinical course. Pediatric-onset SLE (pSLE) represents 10-20% of all SLE cases, and is associated with higher disease severity, including more-rapid damage accrual, than adult-onset SLE. As in adults, pSLE disease expression varies according to ethnicity, with a milder disease course in white patients. The majority of pSLE patients will have developed damage within 5-10 years of disease onset, most frequently involving the musculoskeletal, ocular, renal and neuropsychiatric systems. Owing to improvements in disease management and recognition over the past 20-30 years, patients now live longer, but as a result have increased disease damage. Premature atherosclerosis and osteoporosis have become increasingly prevalent morbidities in pSLE patients. Early atherosclerosis leads to a considerable rise in cardiovascular and cerebrovascular events, and failure to develop adequate peak bone mass during adolescence-a crucial period of bone accrual-is likely to lead to early osteoporosis and fractures. Patients with pSLE have an incurable, potentially devastating disease that occurs during a vulnerable period of psychosocial development, leading to specific and unique psychosocial stressors. Additional large, long-term follow-up studies in pSLE are needed to better understand the disease prognosis and to facilitate development of tailored treatments.

Quantifying calcium intake in school age children: development and validation of the Calcium Counts! food frequency questionnaire

Quantifying dietary behavior is difficult and can be intrusive. Calcium, an essential mineral for skeletal development during childhood, is difficult to assess. Few studies have examined the use of food frequency questionnaires (FFQs) for assessing calcium intake in school-age children. This study evaluated the validity and reliability of the Calcium Counts! FFQ (CCFFQ) for estimating calcium intake in school children in the US. Healthy children, aged 7-10 years (n = 139) completed the CCFFQ and 7-day weighed food records. A subset of subjects completed a second CCFFQ within 3.6 months. Concurrent validity was determined using Pearson correlations between the CCFFQ and food record estimates of calcium intake, and the relationship between quintiles for the two measures. Predictive validity was determined using generalized linear regression models to explore the effects of age, race, and gender. Inter- and intra-individual variability in calcium intake was high (>300 mg/day). Calcium intake was approximately 300 mg/day higher by CCFFQ compared to food records. Concurrent validity was moderate (r = 0.61) for the entire cohort and higher for selected subgroups. Predictive validity estimates yielded significant relationships between CCFFQ and food record estimates of calcium intake alone and in the presence of such potential effect modifiers as age group, race, and gender. Test-retest reliability was high (r = 0.74). Although calcium intake estimated by the CCFFQ was greater than that measured by food records, the CCFFQ provides valid and reliable estimates of calcium intake in children. The CCFFQ is especially well-suited as a tool to identify children with low calcium intakes.

Interventions to prevent obesity in 0-5 year olds: an updated systematic review of the literature

The small number and recency of the early childhood obesity-prevention literature identified in a previous review of interventions to prevent obesity, promote healthy eating, physical activity, and/or reduce sedentary behaviors in 0-5 year olds suggests this is a new and developing research area. The current review was conducted to provide an update of the rapidly emerging evidence in this area and to assess the quality of studies reported. Ten electronic databases were searched to identify literature published from January 1995 to August 2008.

INCLUSION CRITERIA

interventions reporting child anthropometric, diet, physical activity, or sedentary behavior outcomes and focusing on children aged 0-5 years of age.

EXCLUSION CRITERIA

focusing on breastfeeding, eating disorders, obesity treatment, malnutrition, or school-based interventions. Two reviewers independently extracted data and assessed study quality. Twenty-three studies met all criteria. Most were conducted in preschool/childcare (n = 9) or home settings (n = 8). Approximately half targeted socioeconomically disadvantaged children (n = 12) and three quarters were published from 2003 onward (n = 17). The interventions varied widely although most were multifaceted in their approach. While study design and quality varied most studies reported their interventions were feasible and acceptable, although impact on behaviors that contribute to obesity were not achieved by all. Early childhood obesity-prevention interventions represent a rapidly growing research area. Current evidence suggests that behaviors that contribute to obesity can be positively impacted in a range of settings and provides important insights into the most effective strategies for promoting healthy weight from early childhood.

Maximizing bone mineral mass gain during growth for the prevention of fractures in the adolescents and the elderly

Bone mass is a key determinant of fracture risk. Maximizing bone mineral mass during childhood and adolescence may contribute to fracture risk reduction during adolescence and possibly in the elderly. Although more than 60% of the variance of peak bone mass (PBM), the amount of bone present in the skeleton at the end of its maturation process, is genetically determined, the remainder is likely influenced by factors amenable to positive intervention, such as adequate dietary intake of dairy products as a natural source of calcium and proteins, vitamin D, and regular weight-bearing physical activity. Low calcium and vitamin D intakes are associated with negative effects on bone, including suboptimal PBM acquisition. As suggested by intervention studies, regular intake of dairy products may have positive and possibly sustained effects on bone mineral mass gain, contributing thereby to fracture risk reduction. Further evidence from intervention studies suggests that weight-bearing physical activities, such as jumping, may contribute to bone mineral mass gain in children. Optimizing PBM acquisition through dietary and physical exercise measures may represent a valuable primary method for the prevention of fractures.

Management of osteoporosis in central and eastern Europe (CEE): conclusions of the "2nd Summit on Osteoporosis-CEE", 21-22 November 2008, Warsaw, Poland

In November 2008, the "2nd Summit on Osteoporosis-Central and Eastern Europe (CEE)" was held in Warsaw, Poland. Discussions at this meeting focused on the identification and discussion of diagnostic, preventive, and therapeutic measures used in CEE. Evaluated information was used to identify issues regarding diagnosis and therapy of osteoporosis in these countries to facilitate the subsequent setup of appropriate support and development strategies. The main debate was structured according to the following five subjects: (1) present status and future perspectives for implementation of FRAX(R) into local (CEE) diagnostic algorithms, (2) principles of drug selection in osteoporosis treatment in CEE countries, (3) nonpharmacological interventions in osteoporosis treatment and prophylaxis in CEE countries, (4) treatment benefit evaluation, and (5) cost-effectiveness and evaluation of reimbursement policies in CEE countries. The most important and substantial comments of the delegates are summarized in the present article. The multinational panel of experts with representatives from many CEE countries as well as Austria and Switzerland made the "2nd Summit on Osteoporosis-CEE" a perfect platform to identify issues and needs regarding diagnosis and therapy of osteoporosis as well as the cost-effectiveness of osteoporosis management in CEE countries. The information gained will serve as a basis for the development of strategies to resolve the identified issues at the "3rd Summit on Osteoporosis-CEE" in November 2009.