Review
Predictors of serum 25(Oh)D increase following bimonthly supplementation with 100,000 IU vitamin D in healthy, men aged 25–65 years

https://doi.org/10.1016/j.jsbmb.2013.12.005Get rights and content

Highlights

  • The effect of vitamin D supplementation was tested among men with insufficient 25(OH)D levels.

  • Increase in serum 25(OH)D levels following supplementation was related mainly to BMI.

  • Age, sun-exposure, baseline 25(OH)D levels, seasonality and other predictors were insignificant.

  • Vitamin D supplementation model across BMI levels is proposed.

  • Adaptation of vitamin D supplementation in obese people maybe required.

Abstract

Vitamin D replenishment therapy typically entails standard dosages, but related increases in serum 25(OH)D levels vary between individuals. This study was aimed to identify factors that affect the efficacy of vitamin D supplementation.

Subjects and methods

79 healthy men aged 25–65 with 25(OH)D < 20 ng/ml participated in a vitamin D supplementation study. All participants received 100,000 IU vitamin D bimonthly, e.g., 1666 IU/day. Personal and demographic information, physical activity and sun-exposure questionnaires were completed by the participants. Weight, height, and waist circumference were recorded. Serum calcium, creatinine, 25(OH)D, PTH, lipid profile, and liver-enzyme levels were assessed. All measurements were repeated after 6 and 12 months. The difference between baseline serum 25(OH)D and 12-month measurements was calculated (delta). Linear regression was performed to identify predictors for increases in 25(OH)D levels.

Results

Mean serum 25(OH)D level increases according to BMI were 12.6 ± 5.29 ng/ml for BMI  25, 10.12 ± 4.95 ng/ml for 25 < BMI < 30, and only 6.39 ± 5.33  ng/ml for BMI > 30, which differed significantly from the other BMI categories (p = 0.003). In a regression model to predict 25(OH)D increase, BMI was the main predictor (p < 0.001), explaining 21.6% of the variance in serum 25(OH)D (inverse association). Age, sun-exposure, serum cholesterol, physical-activity, baseline 25(OH)D levels and seasonality were insignificant. The full model explained 27.9% of the variance in serum 25(OH)D.

Conclusion

This study's main findings are that BMI affect vitamin D response in healthy men. Quantitative supplementation adjustments may be warranted in obese men, for whom the dose may need to be doubled.

This article is part of a special issue entitled ‘16th Vitamin D Workshop’.

Introduction

The relationship between vitamin D intake and the increase in serum 25(OH)D levels is often inconsistent and is influenced by factors such as seasonality, age, ethnicity, BMI, physical activity and genetic factors [1], [2], [3], [4]. Although the rise in serum 25(OH)D levels following standard vitamin D supplementation varies between individuals, the recommended dosage is the same for everyone, regardless of individual characteristics. Thus, understanding the predictors of the serum 25(OH)D response is needed to determine which factors may influence the status of 25(OH)D. The study aims to determine personal and environmental predictors for the response of 25(OH)D to vitamin D treatment as demonstrated in healthy young men.

Section snippets

Subjects and methods

Predictors for increase in serum 25(OH)D were evaluated in a 12-month vitamin D supplementation trial of healthy men (aged 25–65) with serum 25 (OH) D < 20 ng/ml. Participants were recruited during their annual periodic examinations at the Rambam Medical Center in Haifa, Israel, and via the study's website. The study was approved by the Rambam Health Care Campus review board and registered in ClinicalTrials.gov as NCT01016184 and funded by a grant from The Preventive Action, Safety & Health

Results

The range of baseline serum 25(OH)D levels was 4.0–19.8 ng/ml with a mean increase of 10.18 ± 5.46 ng/ml after 12 months. 29.1% (n = 23) of the participants had BMI < 25 kg/m 53.2%n = 42) had BMI 25–30 kg/m2 and 17.7% (n = 14) had BMI  30 kg/m2 There was a significant difference in lipid levels and age across BMI categories (Table 1). Overall serum 25(OH)D levels were associated with seasons (p = 0.024), such that significantly lower levels were found in the winter than in the autumn (p = 0.017) (data not shown).

Discussion

We showed that BMI is the most powerful predictor for the increase in serum 25(OH)D levels following vitamin D supplementation among generally healthy men. Our findings are in accord with those of Gallagher et al., who showed that BMI is the strongest predictor for the increase in 25(OH)D levels following vitamin D supplementation in healthy postmenopausal women [8]. Similar findings were shown in the Tromsø study among men and women aged 56.7 ± 9.2 years [9], among the elderly [10], and in

References (14)

There are more references available in the full text version of this article.

Cited by (0)

View full text