Familial Clustering of Vitamin D Deficiency Via Shared Environment: The Korean National Health And Nutrition Examination Survey 2008-2012

Vitamin D deficiency is a modifiable risk factor for poor bone health. Familial correlation of serum 25-hydroxyvitamin D concentration (25(OH)D) was reported in twin- or family-based studies, mostly from Caucasian parent-offspring pairs. However, data on the familial association of 25(OH)D in extended family structure and the relative contribution of genetic and shared environmental factors on serum 25(OH)D level are limited in Asian populations. In this study, the investigators aimed to assess the relative contribution of additive genetic and environmental components on serum 25(OH)D level by variance components method in a nationwide family-based cohort. Further, the investigators will evaluate the association of vitamin D status of index individual with prevalent vitamin D deficiency of each family member including spouse, offspring, sibling, and grand-offspring. Additive influences of paternal and maternal vitamin D status on offspring will be also investigated.