Changes in vitamin D status of overweight and obese 6 to 12- year old children: Results from a 1 year, family-centred lifestyle intervention
Bibliographic record
Abstract
Background: Vitamin D status is lower in Canadian children who are overweight or obese compared to children of healthy weights. Objective: The objectives of this study are 1) to determine the vitamin D status of overweight and obese children, 2) to examine the association between changes in fat mass (FM) and vitamin D status, and 3) to determine if there is a relationship between regional adiposity and blood concentrations of 25-hydroxyvitamin D (25(OH)D).Methods: Data was collected at baseline, and then every 3 months for a one year period, from participants enrolled in the McGill Youth and Lifestyle Intervention with Food and Exercise (MYLIFE) study (NCT01290016); healthy children aged 6-12 y with body mass index (BMI)-for-age >85th percentile were included. Chemiluminescence immunoassay was used to measure plasma 25(OH)D. Standard measurements of weight, height and waist circumference (WC) were taken at each visit; BMI and BMI z-scores were calculated (WHO AnthroPlus, Geneva, Switzerland, 2009). Body composition was measured using dual-energy X-ray absorptiometry to determine whole body and regional adiposity. Z-scores for adiposity indicators were calculated based on reference data from the National Health and Nutrition Examination Survey; children were then separated into tertiles based on these z-scores. Constitutive and facultative skin pigmentation was measured using a hand-held spectrophotometer in order to determine Fitzpatrick skin types. Children were categorized according to cutaneous UVB synthesis period. Ethnicity was self-disclosed and pubertal status was reported at baseline and categorized according to Tanner stages. Differences in 25(OH)D among tertiles of each adiposity indicator (eg: % body fat (%BF), FM, WC) were tested using a mixed model ANOVA. Logistic regression was used to determine the odds ratio of not meeting recommended 25(OH)D cutoffs. Results: Data from 101 children (46 boys and 55 girls) were used in this study. The mean 25(OH)D concentration at baseline was 59.8 ± 1.3 nmol/L, with no significant difference between sexes (p=0.740). Boys had lower %BF (p=0.012), greater BMI z-scores (p=0.001) and greater WC (p=0.013) than girls. After one year, those who decreased FM appeared to have better plasma 25(OH)D than those who maintained or gained FM (59.2 vs. 55.3 nmol/L; p=0.310), although significance was not reached. Every kg increase in FM was associated to increased odds of not reaching plasma 25(OH)D cutoffs of 75 nmol/L (OR: 1.2, 95% CI: 1.1-1.4, p=0.006). Arm fat (OR: 2.6, 95% CI: 1.3-5.2, p=0.009) was associated to greater odds of missing the cutoff than leg fat (OR: 1.6, 95% CI: 1.1-2.3, p=0.009). Android:gynoid fat patterning was not significant (p=0.066). Conclusion: Adiposity in overweight and obese children, irrespective of location, has an inverse relationship with vitamin D status. Therefore, adiposity likely needs to be considered when establishing dietary intake recommendations to match population cutoffs for vitamin D status. Future large-scale longitudinal research is required to examine if a reduction in FM would lead to a significant increase in vitamin D status.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".