Association Between Single Gene Polymorphisms and Bone Biomarkers and Response to Calcium and Vitamin D Supplementation in Young Adults Undergoing Military Training.
Study Goal
The researchers aimed to determine whether genetic variations influence biomarkers of bone metabolism and responses to calcium and vitamin D supplementation in young adults undergoing initial military training.
Results Summary
The study found that calcium and vitamin D supplementation reduced stress fracture incidence, suppressed parathyroid hormone, and improved bone health measures compared to placebo. A specific genetic variant (DBP SNP rs7041) was associated with higher baseline vitamin D levels.
Population
Young adults entering Army or Air Force initial military training (n=748, with 391 completers).
Effective Dosage
2000 mg calcium and 1000 IU vitamin D daily.
Duration
7 to 9 weeks.
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
supplemental calcium (Ca) and vitamin D provided daily throughout IMT | decrease | stress fracture incidence | young adults entering IMT | - | reduced | #1 |
supplemental calcium (Ca) and vitamin D provided daily throughout IMT | decrease | parathyroid hormone (PTH) | young adults entering IMT | - | suppressed | #2 |
supplemental calcium (Ca) and vitamin D provided daily throughout IMT | increase | measures of bone health | young adults entering IMT | - | improved | #3 |
- | increase | 25OHD | volunteers starting IMT | B = 4.46, p = 1.97E-10 | positively associated | #4 |
- | increase | 1,25(OH)2D | volunteers starting IMT | - | positively associated | #5 |
Initial military training (IMT) is associated with increased stress fracture risk. In prior studies, supplemental calcium (Ca) and vitamin D provided daily throughout IMT reduced stress fracture incidence, suppressed parathyroid hormone (PTH), and improved measures of bone health compared with placebo. Data were analyzed from a randomized, double-blind, placebo-controlled trial to determine whether single-nucleotide polymorphisms (SNPs) in Ca and vitamin D-related genes were associated with circulating biomarkers of bone metabolism in young adults entering IMT, and whether responses to Ca and vitamin D supplementation were modulated by genotype. Associations between SNPs, including vitamin D receptor (VDR), vitamin D binding protein (DBP), and 1-alpha-hydroxylase (CYP27B1), and circulating biomarkers were measured in fasting blood samples from volunteers (n = 748) starting IMT. Volunteers were block randomized by race and sex to receive Ca (2000 mg) and vitamin D (1000 IU) or placebo daily throughout Army or Air Force IMT (7 to 9 weeks). Total Ca and vitamin D intakes were calculated as the sum of supplemental intake based on intervention compliance and dietary intake. Relationships between SNPs, Ca, and vitamin D intake tertile and change in biomarkers were evaluated in trial completers (n = 391). At baseline, the minor allele of a DBP SNP (rs7041) was positively associated with both 25OHD (B = 4.46, p = 1.97E-10) and 1,25(OH)