Familial Clustering of Vitamin D Deficiency Via Shared Environment: The Korean National Health And Nutrition Examination Survey 2008-2012
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.
From the Korean National Health and Nutritional Examination Survey (KNHANES) conducted
 between 2008 and 2012, familial correlations for 25(OH)D will be estimated in different types
 of family relation pairs in 28551 subjects from 10882 families. The relative contribution of
 additive genetic and shared or individual environmental factors for variance of 25(OH)D level
 will be calculated using variance component method. Interactions between paternal and
 maternal vitamin D status for 25(OH)D level of offspring will be evaluated.
Inclusion Criteria:

 -  KNHANES(Korean National Health and Nutrition Examination Survey) 2008-2012
 participants

 Exclusion Criteria:

 -  missing value on 25-hydroxyvitamin D levels

 -  data on another household member was unavailable

 -  the precise family relationship between the subjects was unclear