Vitamin D status is associated with bone mineral density and bone mineral content in preschool-aged children.

This study examined the associations between vitamin D status, bone mineral content (BMC), areal bone mineral density (aBMD), and markers of calcium homeostasis in preschool-aged children. Children (n=488; age range: 1.8-6.0 y) were randomly recruited from Montreal. The distal forearm was scanned using a peripheral dual-energy X-ray absorptiometry scanner (Lunar PIXI; GE Healthcare, Fairfield, CT). A subset (n=81) had clinical dual-energy X-ray absorptiometry (cDXA) scans (Hologic 4500A Discovery Series) of lumbar spine (LS) 1-4, whole body, and ultradistal forearm. All were assessed for plasma 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone concentrations (Liaison; Diasorin), ionized calcium (ABL80 FLEX; Radiometer Medical A/S), and dietary vitamin D and calcium intakes by survey. Age (p<0.001) and weight-for-age Z-score (p<0.001) were positively associated with BMC and aBMD in all regression models, whereas male sex contributed positively to forearm BMC and aBMD. Having a 25(OH)D concentration of >75 nmol/L positively associated with forearm and whole body BMC and aBMD (p<0.036). Sun index related to (p<0.029) cDXA forearm and LS 1-4 BMC and whole-body aBMD. Nutrient intakes did not relate to BMC or aBMD. In conclusion, higher vitamin D status is linked to higher BMC and aBMD of forearm and whole body in preschool-aged children.

Higher concentrations of vitamin D in Canadian children with juvenile idiopathic arthritis compared to healthy controls are associated with more frequent use of vitamin D supplements and season of birth.

A number of studies have demonstrated that patients with autoimmune disease have lower levels of vitamin D prompting speculation that vitamin D might suppress inflammation and immune responses in children with juvenile idiopathic arthritis (JIA).  The objective of this study was to compare vitamin D levels in children with JIA at disease onset with healthy children. We hypothesized that children and adolescents with JIA have lower vitamin D levels than healthy children and adolescents. Data from a Canadian cohort of children with new-onset JIA (n= 164, data collection 2007-2012) were compared to Canadian Health Measures Survey (CHMS) data (n=4027, data collection 2007-2011). We compared 25-hydroxy vitamin D (25(OH)D) concentrations with measures of inflammation, vitamin D supplement use, milk intake, and season of birth. Mean 25(OH)D level was significantly higher in patients with JIA (79 ± 3.1 nmol/L) than in healthy controls (68 ± 1.8 nmol/L P <.05). Patients with JIA more often used vitamin D containing supplements (50% vs. 7%; P <.05). The prevalence of 25(OH)D deficiency (<30 nmol/L) was 6% for both groups. Children with JIA with 25(OH)D deficiency or insufficiency (<50 nmol/L) had higher C-reactive protein levels. Children with JIA were more often born in the fall and winter compared to healthy children. In contrast to earlier studies, we found vitamin D levels in Canadian children with JIA were higher compared to healthy children and associated with more frequent use of vitamin D supplements. Among children with JIA, low vitamin D levels were associated with indicators of greater inflammation.

Postnatal vitamin D supplementation following maternal dietary vitamin D deficiency does not affect bone mass in weanling guinea pigs.

Although vitamin D deficiency is common at birth, the consequences to growth and bone mass by weaning are unclear. This study was designed to determine whether maternal dietary vitamin D deficiency in pregnancy has a negative impact on the bone mass of full-term neonates and if postnatal supplementation could restore bone mass. Forty guinea pigs were randomized to receive a control (C) or deficient (D) diet (0.03 microg vs. 0.00 microg cholecalciferol/g) during pregnancy. Offspring were randomized at birth to receive 0.25 microg of cholecalciferol supplement (S) or a placebo (P) orally per day for 28 d. Measurements at birth and d 28 included whole body and regional bone mass and serum osteocalcin and deoxypyridinoline, plus biomechanical testing and peripheral quantitative computed tomography of excised tibias and femurs. Main and interactive effects were tested using mixed model ANOVA and post hoc Bonferroni's tests. At birth and d 28, offspring of the D sows had lower serum vitamin D and osteocalcin concentration, lower body weight, length, whole body and total tibia bone mineral content, and lower biomechanical integrity of tibia compared with those of the C sows, regardless of supplementation. Although postnatal vitamin D supplementation improved vitamin D status at d 28 in D offspring, values remained significantly lower than C groups. This study suggests that efforts should be made to optimize maternal vitamin D status in pregnancy, along with maintenance of vitamin D status in infancy, rather than relying on postnatal supplementation to normalize vitamin D status and bone mass.

Vitamin D and juvenile idiopathic arthritis.

BACKGROUND: Vitamin D has been implicated in the pathogenesis of autoimmune diseases. While the roles of vitamin D in other autoimmune diseases have been investigated, less is known about the role of vitamin D in chronic childhood arthritis. MAIN BODY: This review summarizes and evaluates evidence relating to 25-hydroxyvitamin D (25(OH)D) and chronic childhood arthritis. A scoping literature review was conducted using Ovid Medline, Ovid Embase, Cumulative Index to Nursing and Allied Health Literature, Web of Science and Scopus. Further, we geo-mapped the results of the studies to identify the patterns of the association between vitamin D and chronic childhood arthritis across the globe. Of 38 studies reporting 25(OH)D concentrations in childhood chronic arthritis, 32 (84.2%) reported that a significant number of children had suboptimal (< 75 nmol/L) status. CONCLUSION: The data indicate suboptimal vitamin D status in children with chronic arthritis. Further, the association between low vitamin D and increased arthritis activity follow a north-south geographical gradient.

Impact of replacing regular chocolate milk with the reduced-sugar option on milk consumption in elementary schools in Saskatoon, Canada.

Excess sugar consumption in children has led to the removal of chocolate milk from some schools. Lower-sugar formulations, if accepted, would provide the benefits of milk consumption. In a cross-over trial, milk consumption was measured in 8 schools over 6 weeks in 2 phases: phase 1 provided standard 1% chocolate milk and plain 2% milk choices for the first 3 weeks, and phase 2 provided reduced-sugar 1% chocolate milk and plain 2% milk for the next 3 weeks. Milk selection and milk wasted were measured by sex and grade (1-8). Children chose chocolate milk more often than white milk in both phases (phase 1, 8.93% ± 0.75% vs. 0.87% ± 0.11% (p < 0.001), and phase 2, 5.76% ± 0.29% vs. 0.78% ± 0.14% (p < 0.001), respectively). Fewer children chose reduced-sugar chocolate milk in phase 2 (p < 0.001). A greater percentage of younger students (grades 1-4) than older students (grades 5-8) purchased milk in both phases (phase 1, 11.10% ± 0.81% vs. 8.36% ± 0.74%, p = 0.020, and phase 2, 8.47% ± 0.43% vs. 4.62% ± 0.40%, p < 0.001, respectively); older children drank more milk at lunch. Schoolchildren preferred chocolate milk over plain milk even when a reduced-sugar formula was offered; however, switching to reduced-sugar chocolate milk led to a decrease in the number of students choosing milk. Longer-duration studies are required to determine if students would purchase reduced-sugar chocolate milk at the same rate as they would purchase regular chocolate milk.

Impact of the removal of chocolate milk from school milk programs for children in Saskatoon, Canada.

Studies in the United States report inclusion of flavoured milk in the diets of children and youth improves nutrient intakes. No research has investigated the contribution of flavoured milk to overall milk intake or the milk preferences of Canadian children. The objective of the study was to measure milk consumption (plain milk and flavoured milk) by children in an elementary school environment and investigate factors contributing to milk choice. A mixed-method research design was applied across 6 schools for 12 weeks. Milk waste was measured in grades 1-8 for 12 weeks. Weeks 1-4 (phase 1) and 9-12 (phase 3) provided both plain milk and flavoured milk as chocolate milk while weeks 5-8 (phase 2) provided plain milk only. Beverage Frequency Questionnaires were used in each phase (in grades 5-8 only) to assess usual beverage consumption. Statistical nutrient modelling was conducted to determine the effects of removing chocolate milk during phase 2 as a milk choice. Later, focus groups were conducted with students in grades 5-8 to determine what influences them to choose/not choose to drink milk. Total milk intake decreased by 12.3% when chocolate milk was removed from the schools (26.6% ± 5.2% to 14.31% ± 1.6%, p < 0.001). Milk choice was influenced by environmental factors as well as taste, cost, convenience, and variety. Total milk intake was associated with location (p = 0.035) and cost (p < 0.001), with rural students and/or those students receiving free milk drinking the greatest amount of milk. Nutrient modelling revealed chocolate milk is more cost-efficient and convenient at providing nutrients than alternative food/drink combinations.

Normative data and predictors of leg muscle function and postural control in children.

INTRODUCTION: At the present there are limited tools available to measure muscle function in young children. Ground reaction force plates measure lower-body function and postural control in older children and adults. The purpose of this study was threefold: 1) develop normative data for evaluating global muscle development; 2) determine the reproducibility of ground reaction force plates for assessing muscle function in preschool-age children; and 3) identify predictors of skeletal muscle function. METHODS: Children's (n = 81, 1.8 to 6.0 yr; M = 52%) muscle function and postural control was measured for jump (JMP), sit-to-stand (STS), and both undistracted and distracted body sway tests using a ground reaction force plate (Kistler 9200A). Whole body composition used dual-energy x-ray absorptiometry (Hologic 4500A Discovery Series). Plasma 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone concentrations were measured by chemiluminescence (Liaison, Diasorin, Mississauga, ON, Canada) as well as ionized calcium (ABL80 FLEX, Radiometer Medical A/S). Demographics, and anthropometry were collected. ANOVA and linear regression were used to identify predictors. Reproducibility was assessed by intersubject coefficient of variation. RESULTS: Age was a consistent predictor in all models; body size or fat and lean mass were important predictors in 3 of the models - STS peak force, STS peak power, and JMP peak power. STS was the most reproducible maneuver (average coefficient of variation =15.7%). Distracted body sway testing was not appropriate in these youngsters. CONCLUSION: The novel data presented in this study demonstrate a clear age (developmental) effect without any effect of sex on muscle function and postural control in young children. Lean muscle mass was important in some models (STS peak force and JMP peak power). The STS test was the best of the 4 maneuvers.