Table 1.

Baseline characteristics of participantsa

Intervention (n = 19,541)Comparison (n = 29,294)
N (%)N (%)
Age, y
 50–597,206 (36.9)10,792 (36.8)
 60–699,083 (46.5)13,632 (46.5)
 70–793,252 (16.6)4,870 (16.6)
Race/ethnicity
 White15,871 (81.2)23,891 (81.6)
 Black2,135 (10.9)3,127 (10.7)
 Hispanic751 (3.8)1,094 (3.7)
 American Indian88 (0.5)114 (0.4)
 Asian/Pacific Islander431 (2.2)674 (2.3)
 Unknown265 (1.4)394 (1.3)
Education
 Less than high school diploma or GED4,267 (21.8)6,468 (22.1)
 Some school after high school diploma7,712 (39.5)11,597 (39.6)
 College degree or higher7,446 (38.1)11,044 (37.7)
Body mass index (kg/m2)
 <255,072 (26.0)7,587 (25.9)
 25–<306,944 (35.5)10,452 (35.7)
 ≥307,442 (38.1)11,125 (38.0)
Smoking status
 Never9,918 (50.8)15,029 (51.3)
 Past8,121 (41.6)11,979 (40.9)
 Current1,273 (6.5)1,977 (6.7)
NSAID use
 Yes6,316 (32.3)9,796 (33.4)
 No13,224 (67.7)19,498 (66.6)
Total vitamin D intake, IUb
 <200 IU7,763 (39.7)11,892 (40.6)
 200 to <400 IU3,986 (20.4)5,787 (19.8)
 400 to <600 IU4,454 (22.8)6,602 (22.5)
 ≥600 IU3,226 (16.5)4,892 (16.7)
Total energy intake, kcal
 <1,2964,820 (24.7)7,327 (25.0)
 1,296 to <1,6774,924 (25.2)7,226 (24.7)
 1,677 to <2,1504,879 (25.0)7,267 (24.8)
 ≥2,1504,807 (24.6)7,353 (25.1)
Percent energy from total fat,%
 <33.84,892 (25.0)7,109 (24.3)
 33.8 to <36.94,885 (25.0)7,536 (25.7)
 36.9 to <40.84,752 (24.3)7,285 (24.9)
 ≥40.84,901 (25.1)7,243 (24.7)
Total fat intake, grams
 <52.44,828 (24.7)7,322 (25.0)
 52.4 to <69.04,897 (25.1)7,265 (24.8)
 69.0 to <91.24,893 (25.0)7,243 (24.7)
 ≥91.24,812 (24.6)7,343 (25.1)
Total vegetable and fruit servings per day
 <2.35,013 (25.7)7,500 (25.6)
 2.3 to <3.34,696 (24.0)7,090 (24.2)
 3.3 to <4.64,755 (24.3)7,104 (24.3)
 ≥4.64,966 (25.4)7,479 (25.5)
Total grain servings per day
 <3.04,789 (24.5)7,250 (24.7)
 3.0 to <4.35,096 (26.1)7,407 (25.3)
 4.3 to <5.94,727 (24.2)7,029 (24.0)
 ≥5.94,818 (24.7)7,487 (25.6)
Regional solar radiation, langleysc
 300–3255,661 (29.0)8,512 (29.1)
 3503,801 (19.5)5,701 (19.5)
 375–3802,292 (11.7)3,435 (11.7)
 400–4303,398 (17.4)5,088 (17.4)
 475–5004,381 (22.4)6,548 (22.4)
Total outdoor walking energy expenditure, METs/wk
 06,714 (34.4)9,817 (33.5)
 ≤3.53,791 (19.4)5,790 (19.8)
 3.6–7.03,341 (17.1)5,114 (17.5)
 >7.03,661 (18.7)5,532 (18.9)
History of cancerd
 Yes853 (4.4)1,286 (4.4)
 No18,688 (95.6)28,008 (95.6)
History of melanoma
 Yes122 (0.6)170 (0.6)
 No19,419 (99.4)29,124 (99.4)
History of nonmelanoma skin cancer
 Yes1,264 (6.5)1,996 (6.8)
 No18,277 (93.5)27,298 (93.2)
Hormone therapy use
 Never used8,072 (41.3)12,102 (41.3)
 Past user2,813 (14.4)4,181 (14.3)
 Current user8,639 (44.2)12,979 (44.3)
Hormone therapy intervention assignment
 Not randomly assigned16,359 (83.7)24,426 (83.4)
 Active1,587 (8.1)2,496 (8.5)
 Placebo1,595 (8.2)2,372 (8.1)
Calcium/vitamin D intervention assignment
 Not randomly assigned9,896 (50.6)13,729 (46.9)
 Active4,767 (24.4)7,827 (26.7)
 Placebo4,878 (25.0)7,738 (26.4)

GED, general equivalency diploma; MET, metabolic equivalent tasks.

  • aPercentages may not total 100% because of missing data.

  • bFrom diet and supplements.

  • cBased on the mean annual amount of sunlight reaching the clinic site as measured by the U.S. Weather Bureau; 1 langley = 1 g-cal/cm2.

  • dHistory of cancer (cancers diagnosed more than 10 years before enrollment) is defined as any cancer except nonmelanoma skin cancer.