This Article Full Text Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Google Scholar Articles by Arguelles, L. M. Articles by Wang, X. PubMed PubMed Citation Articles by Arguelles, L. M. Articles by Wang, X. Related Collections Calcium and Bone Metabolism

Heritability and Environmental Factors Affecting Vitamin D Status in Rural Chinese Adolescent Twins

Mary Ann and J. Milburn Smith Child Health Research Program (L.M.A., C.B.L., A.J.A., Xi.L., S.Z., X.H., B.W., X.W.), Children’s Memorial Hospital and Children’s Memorial Research Center, and the Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60208; Kidney Diseases (C.B.L., F.N.A., H.P.), and Hematology, Oncology, and Transplantation (K.D.), Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60208; Institute for Biomedicine (H.X., Z.L., Xu.L., W.Z.), Anhui Medical University, Hefei 230032, China; and Center for Population Genetics (X.X.), University of Illinois at Chicago School of Public Health, Chicago, Illinois 60612

Address all correspondence and requests for reprints to: Lester M. Arguelles, M.S., Ph.D., Mary Ann and J. Milburn Smith Child Health Research Program, Children’s Memorial Hospital and Children’s Memorial Research Center, 2300 Children’s Plaza, Box 157, Chicago, Illinois 60614-3394. E-mail: LArguelles{at}childrensmemorial.org.

Context: Factors associated with the high prevalence of vitamin D deficiency in China are not well described, especially among Chinese adolescents.

Objectives: The aim of the study was to examine important environmental or sociodemographic factors influencing 25-hydroxyvitamin D [25(OH)D] levels and estimate its heritability.

Design: A sample of 226 male and female adolescent twins aged 13–20 yr from a large prospective twin cohort of rural Chinese children and adolescents that has been followed for 6 yr were evaluated.

Main Outcome Measure(s): Blood level of 25(OH)D was measured using tandem mass spectrometry methodology.

Results: The overall mean (SD) 25(OH)D level was 18.0 (9.4) ng/ml, with wide variation by gender and season. In males (47.4% of subjects), the mean (SD) 25(OH)D level was 12.1 (4.2) ng/ml in non-summer and 27.4 (8.8) ng/ml in summer; in females, it was 10.1 (4.1) ng/ml in non-summer and 19.5 (6.3) ng/ml in summer. A multivariate model that included gender, age, season, physical activity, and student status demonstrated that male gender, summer season, and high physical activity significantly increased 25(OH)D levels. Summer season and male gender also significantly decreased the risk of being in the lowest 25(OH)D tertile. Overall, 68.9% of the variability in 25(OH)D level was attributable to additive genetic influence. Stratification by gender found that in males, 85.9% of the variability in 25(OH)D level was attributable to such influence, but in females, it was only 17%.

Conclusion: In this sample of rural Chinese adolescents, 25(OH)D level was influenced by gender, season, and physical activity level. There was a strong genetic influence on 25(OH)D level in males only.