Background: Vitamin D is synthesized in the skin under the action of solar ultraviolet-B radiation. The objective of this study was to determine whether a simple question exploring sun exposure (When weather is nice, do you stay more than 15 minutes ...
Background: Diet is a major exogenous source of vitamin D. The objective of this analysis was to determine whether the yes/no answer to a simple question exploring diet (Do you eat fatty fish at least once a week and/or eggs several times per week?) ...