What factors modify the effect of monthly bolus dose vitamin D supplementation on 25-hydroxyvitamin D concentrations?

• Published in: The Journal of steroid biochemistry and molecular biology Vol. 201; p. 105687
• Main Authors: Wu, Zhenqiang, Camargo, Carlos A., Reid, Ian R., Beros, Angela, Sluyter, John D., Waayer, Debbie, Lawes, Carlene M.M., Toop, Les, Khaw, Kay-Tee, Scragg, Robert
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.07.2020; Elsevier BV
• Subjects: 25-Hydroxyvitamin D; Asthma; Body mass index; Bone density; Chronic obstructive pulmonary disease; Dietary supplements; Effect modification; Ethnicity; Minority & ethnic groups; Physical activity; Randomized controlled trial; Supplements; Tobacco; Tobacco smoking; Vitamin D; Vitamin D supplementation; Vitamin D3; Effect modification; Randomized controlled trial; Vitamin D supplementation; 25-Hydroxyvitamin D
• ISSN: 0960-0760; 1879-1220; 1879-1220
• DOI: 10.1016/j.jsbmb.2020.105687

•The 25(OH)D response to vitamin D supplementation differs between studies.•There is little research on factors that modify the 25(OH)D response to vitamin D.•We investigated effect modifiers in participants in a vitamin D supplement trial.•Age, sex, 25(OH)D, BMI and sun exposure modify the 25(OH)D response to vitamin D. The increasing use of vitamin D supplements has stimulated interest in identifying factors that may modify the effect of supplementation on circulating 25-hydroxyvitamin D (25(OH)D) concentrations. Such information is of potential interest to researchers, clinicians and patients when deciding on bolus dose of vitamin D supplementation. We carried out a large randomized controlled trial of 5110 adults aged 50–84 years, of European/Other (84%), Polynesian (11%) and Asian (5%) ethnicity, to whom we gave a standard dose of vitamin D3 supplements (200,000 IU initially, then 100,000 IU monthly) which was taken with high adherence. All participants provided a baseline blood sample, and follow-up blood samples were collected at 6 months and annually for 3 years in a random sample of 441 participants, and also at 2 years in 413 participants enrolled in a bone density sub-study. Serum 25(OH)D was measured by LC/MSMS. Mixed model analyses were carried out on all 854 participants providing follow-up blood samples in multivariable models that included age, sex, ethnicity, body mass index (kg/m2), tobacco smoking, alcohol intake, physical activity, sun exposure, season, medical prescription of high-dose vitamin D3 (Cal.D.Forte tablets), asthma/COPD and the study treatment (vitamin D or placebo). The adjusted mean difference in 25(OH)D in the follow-up points between vitamin D supplementation and placebo groups was inversely related (all p for interaction <0.05) to baseline 25(OH)D, BMI, and hours of sun exposure, and higher in females, elders, and those with high frequency of alcohol, medical prescription of vitamin D, and asthma/COPD. The mean difference was not significantly related to ethnicity (p = 0.12), tobacco (p = 0.34), and vigorous activity (p = 0.33). In summary, these data show that vitamin D status, BMI, sun exposure hours, sex and asthma/COPD modify the 25(OH)D response to vitamin D supplementation. By contrast, ethnicity, tobacco smoking, and vigorous activity do not.