Table 1.

Ancestry estimation and other characteristics of 758 SCCS participants

CharacteristicAfrican-American (N = 379)White (N = 379)
No. of females/males187/192187/192
Median (IQR) percentage African ancestry0.971 (0.887-0.997)0.004 (0.003-0.009)
Median (IQR) percentage European ancestry0.029 (0.003-0.113)0.996 (0.991-0.997)
Ancestry categories
    White/European 0379 (100%)
    African - low (<85%)60 (16%)0
    African - medium (85%-94.99%)106 (28%)0
    African - high (≥95%)213 (56%)0
Mean (SD) serum 25(OH)D levels, ng/mL17.5 (8.6)27.2 (11.1)
Mean (SD) age, y51.9 (9.0)54.1 (9.5)
Mean (SD) body mass index,* kg/m228.3 (5.6)28.4 (5.8)
Mean (SD) daily dietary intake of vitamin D, IU218 (213)269 (236)
Mean (SD) residential UV radiation score5.2 (1.9)5.2 (2.0)
Season of enrollment
    % In winter 17%22%
    % In spring 30%27%
    % In summer25%26%
    % In fall28%25%
% Current smoker*34%34%
% Currently working41%34%
% With less than high school education35%27%

Abbreviations: IQR, interquartile range.

  • *Selection/matching factor.

  • From food sources, and multivitamin and calcium supplement sources.

  • Winter: December to February; spring: March to May; summer: June to August; fall: September to November.