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Association Between Single Gene Polymorphisms and Bone Biomarkers and Response to Calcium and Vitamin D Supplementation in Young Adults Undergoing Military Training.
Gaffney-Stomberg, E, Lutz, LJ, Shcherbina, A, Ricke, DO, Petrovick, M, Cropper, TL, Cable, SJ, McClung, JP
Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research. 2017;32(3):498-507
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The risk of stress fracture is increased in initial military training (IMT) largely because of unaccustomed activity, resulting in a change in calcium and vitamin D levels. Genetic polymorphisms are variations in a gene that affect the level of gene expression, and bone metabolism and absorption is impacted by this. The primary aim of this randomised, double-blind, placebo controlled trial was to determine whether genes related to Calcium and vitamin D were associated with markers of bone metabolism in 748 young adults entering military training. Participants were randomised to consume bars between meals that were either supplemented with Calcium and vitamin D or placebo that were matched in taste and appearance. Fasting blood samples were taken before and after the 7- to 9-week IMT programme to assess circulating biomarkers and genes. This study found that genetic polymorphisms related to Calcium and vitamin D were associated with vitamin D status and markers of bone metabolism. It also found that genes could predict change in vitamin D absorption levels. Based on these results, the authors conclude this study provides novel insight that helps further understanding between genetics, environment and bone metabolism.
Abstract
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)2 D3 (B = 9.63, p < 0.001). Combined genetic risk score (GRS) for this SNP and a second SNP in the VDR gene (rs1544410) was inversely associated with baseline 25OHD (r = -0.28, p < 0.001) and response to Ca and vitamin D intake differed by GRS (p < 0.05). In addition, presence of the minor allele of a second VDR SNP (rs2228570) was associated with lower P1NP (B = -4.83, p = 0.04) and osteocalcin (B = -0.59, p = 0.03). These data suggest that VDR and DBP SNPs are associated with 25OHD status and bone turnover and those with the highest GRS require the greatest vitamin D intake to improve 25OHD during IMT. © 2016 American Society for Bone and Mineral Research.
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The association of calcium and vitamin D with risk of colorectal adenomas.
Hartman, TJ, Albert, PS, Snyder, K, Slattery, ML, Caan, B, Paskett, E, Iber, F, Kikendall, JW, Marshall, J, Shike, M, et al
The Journal of nutrition. 2005;135(2):252-9
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Calcium and vitamin D may play a role in colorectal cancer incidence. One possible explanation is that they may act synergistically on a number of mechanisms to protect against recurrence of colonic adenomas. The aim of the study was to determine the effects of a high-fibre, high-fruit and vegetable, and low-fat diet on the recurrence of adenomatous polyps in the large bowel. For the present study, 1905 participants from the 2079 Polyp Prevention Trial participants who completed the full trial follow-up were evaluated. The participants’ diet was assessed at baseline and annually, and they also received full colonoscopies at baseline, their 1-year visit and at the end of the trial i.e. 4 years after randomization. Results show that there were no significant associations between any of the adenoma recurrence outcome variables and dietary or total calcium intake, consumption of low or high-fat dairy products or dietary vitamin D intake. However, total vitamin D intake was weakly inversely associated with adenoma recurrence. Calcium and vitamin D supplementation were also inversely associated with single and multiple adenoma recurrence. The study shows that calcium and vitamin D intake may provide weakly protective associations with the risk for recurrence of adenoma polyps.
Abstract
The Polyp Prevention Trial (PPT) was a multicenter randomized clinical trial designed to determine the effects of a high-fiber, high-fruit and vegetable, low-fat diet on the recurrence of adenomatous polyps in the large bowel. Detailed dietary intake and supplement use data were collected at baseline and at each of 4 annual study visits. Adenoma recurrence was ascertained by complete colonoscopy at baseline and after 1 and 4 y. Recurrence was found in 754 of the 1905 trial participants. We evaluated the association between calcium and vitamin D intake and adenomatous polyp recurrence after adjusting for intervention group, age, gender, nonsteroidal anti-inflammatory drug use, total energy intake, and the interaction of gender and intervention group. Vitamin D models were also adjusted for the location of the clinic site. Dietary variables were adjusted for total energy intake via the residual method. There were no overall significant associations between adenoma recurrence and dietary calcium intake [odds ratio (OR) for the 5th compared with the lowest quintile = 0.91; 95% CI = 0.67-1.23; P-trend = 0.68], total calcium intake (OR = 0.86; 95% CI = 0.62-1.18; P-trend = 0.20), or dietary vitamin D intake (OR = 0.93; 95% CI = 0.69-1.25; P-trend = 0.43) averaged over follow-up. Total vitamin D intake was weakly inversely associated with adenoma recurrence (OR = 0.84; 95% CI = 0.62-1.13; P-trend = 0.03). Supplemental calcium and vitamin D use during follow-up also were inversely associated with adenoma recurrence (OR for any compared with no use = 0.82; 95% CI = 0.68-0.99; and OR = 0.82; 95% CI = 0.68-0.99; for calcium and vitamin D, respectively). Slightly stronger associations were noted for the prevention of multiple recurrences. Our analyses did not suggest a significant effect modification between total calcium and total vitamin D intake (P = 0.14) on risk for adenoma recurrence. This trial cohort provides some evidence that calcium and vitamin D may be inversely associated with adenoma recurrence.