Univariate analysis of study participants with 25(OH)D values <20 ng/mL and >20 ng/mL.

*All categorical variables were analyzed by Fisher's exact test. Continuous variables were analyzed by Mann Whitney test. † Mean UV index during month of blood draw in Oklahoma, residence of all participants. aBMI = Body Mass Index; bCI = Confidence Interval; cUV = Ultraviolet, Vitamin use refers to self-reported multivitamin use with vitamins containing vitamin D, or calcium with vitamin D; dvariables included in the multivariate regression analysis.