Heritability and seasonal variability of vitamin D concentrations in male twins

Cristina Karohl, Shaoyong Su, Meena Kumari, Vin Tangpricha, Emir Veledar, Viola Vaccarino, Paolo Raggi

Research output: Contribution to journalArticlepeer-review

100 Scopus citations


Background: Serum 25-hydroxyvitamin D [25(OH)D] concentrations can be affected by several environmental and individual factors. It is not clear to what extent genetic influences play a role in determining vitamin D status. Thus far, studies on the heritability of vitamin D have provided conflicting results. Objective: We estimated the heritability of vitamin D concentrations and the effect of season on heritability estimates. Design: We measured serum 25(OH)D concentrations in 510 middle-aged, male twins (310 monozygotic and 200 dizygotic twins) selected from the Vietnam Era Twin Registry. Generalized estimating equations were used to test the association between 25(OH)D and other study factors. Structural equation modeling was used to estimate the heritability of 25(OH)D. Results: The twins' mean (±SD) age was 55 ± 2.8 y. The mean (±SD) 25(OH)D concentration was 38.4 ± 23.3 ng/mL with a substantial seasonal variation (a 6.1-ng/mL lower value during the winter than during the summer, P = 0.003). Approximately 70% of the variation in 25(OH)D concentrations during the winter was explained by genetic factors. However, in the summer, 25(OH)D concentrations were not heritable. During the summer, 53% of the variation in 25(OH)D concentrations was due to shared environmental factors, and 47% of the variation in 25(OH)D concentrations was due to unique environmental factors. Conclusions: Serum 25(OH)D concentrations are highly heritable during the winter season only. In the summer, environmental conditions (eg, sun exposure) prevail over genetic backgrounds in determining serum 25(OH)D concentrations. This trial was registered at clinicaltrials.gov as NCT00017836.

Original languageEnglish (US)
Pages (from-to)1393-1398
Number of pages6
JournalAmerican Journal of Clinical Nutrition
Issue number6
StatePublished - Dec 1 2010
Externally publishedYes

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics


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