Table 1.
Baseline demographic, health, and behavioral characteristics among VITAL participants, according to randomized treatment assignmenta
| Baseline Characteristic | Total cohortb (n=25,874) | Vitamin D and Omega-3 fatty acid (n=6,463) | Vitamin D and Placebo (n=6,464) | Placebo and Omega-3 fatty acid (n=6,472) | Placebo and Placebo (n=6,475) |
|---|---|---|---|---|---|
| Demographic characteristics | |||||
| Sex, % | 25,874 / 100.0 | ||||
| Male | 12,793 / 49.4 | 49.4 | 49.4 | 49.4 | 49.5 |
| Female | 13081 / 50.6 | 50.6 | 50.6 | 50.6 | 50.5 |
| Mean age (SD), years | 67.1 (7.1) | 67.1 (7.1) | 67.1 (7.0) | 67.2 (7.1) | 67.1 (7.1) |
| Age group, years, % | 25,874 / 100.0 | ||||
| 50–54 | 977 / 3.8 | 3.8 | 3.8 | 3.7 | 3.8 |
| 55–64 | 8,871 / 34.3 | 34.2 | 34.3 | 34.3 | 34.3 |
| 65–74 | 12,708 / 49.1 | 49.1 | 49.2 | 49.2 | 49.1 |
| ≥75 | 3,318 / 12.8 | 12.9 | 12.7 | 12.8 | 12.8 |
| Race/ethnicity, %c | 25,307 / 97.8 | ||||
| Non-Hispanic White | 18,047 / 71.3 | 71.3 | 71.2 | 71.6 | 71.1 |
| African American | 5,107 / 20.2 | 20.2 | 20.2 | 20.1 | 20.2 |
| Hispanic (not African American) | 1,013 / 4.0 | 3.9 | 4.3 | 3.9 | 4.0 |
| Asian/Pacific Islander | 389 / 1.5 | 1.6 | 1.4 | 1.5 | 1.6 |
| American Indian/Alaskan Native | 228 / 0.9 | 1.0 | 0.9 | 0.9 | 0.8 |
| Other/unknown | 523 / 2.1 | 2.0 | 2.1 | 1.9 | 2.2 |
| Geographic region, % | 25,873 / 100.0 | ||||
| West (Far west, Southwest, Mtn) | 5,928 / 22.9 | 23.1 | 22.3 | 23.1 | 23.1 |
| Midwest | 5,541 / 21.4 | 22.1 | 20.8 | 21.0 | 21.7 |
| Southeast | 7,242 / 28.0 | 27.6 | 28.3 | 28.1 | 27.9 |
| Northeast | 7,162 / 27.7 | 27.1 | 28.6 | 27.7 | 27.3 |
| Education, % | 25,821 / 99.8 | ||||
| Did not complete high school | 359 / 1.4 | 1.5 | 1.6 | 1.2 | 1.3 |
| High school diploma or GED | 2,945 / 11.4 | 11.7 | 10.8 | 11.6 | 11.5 |
| Attended or graduated from college | 10,853 / 42.0 | 42.0 | 42.4 | 42.0 | 41.8 |
| Post-college | 11,664 / 45.2 | 44.8 | 45.3 | 45.2 | 45.4 |
| Income, % | 23,276 / 90.0 | ||||
| <$15,000 | 1,474 / 6.3 | 6.1 | 6.4 | 6.5 | 6.4 |
| $15,000–49,999 | 7,050 / 30.3 | 30.8 | 30.6 | 29.5 | 30.4 |
| $50,000–89,999 | 6,752 / 29.0 | 29.4 | 28.3 | 29.5 | 28.9 |
| $90,000–120,000 | 3,786 /16.3 | 15.8 | 16.3 | 16.6 | 16.4 |
| >$120,000 | 4214 / 18.1 | 17.9 | 18.5 | 18.0 | 18.0 |
| Health history | |||||
| Mean body mass index (SD), kg/m2 | 28.1 (5.7) | 28.1 (5.7) | 28.1 (5.7) | 28.1 (5.8) | 28.0 (5.8) |
| Obesity, %d | 7,205 / 28.8 | 29.4 | 28.7 | 29.1 | 28.1 |
| Hypertension, %e | 13,721 / 53.6 | 52.2 | 54.3 | 54.3 | 53.7 |
| Ever use of anti-hypertensive medication, % | 13,169 / 51.2 | 49.8 | 52.0 | 51.8 | 51.4 |
| Current use of cholesterol-lowering medication, % | 9,525 / 37.5 | 38.0 | 37.9 | 37.4 | 36.5 |
| Diabetes, %f | 3,402 / 13.2 | 13.8 | 13.3 | 13.1 | 12.8 |
| Current use of antidiabetic medication, % | 2,728 / 10.5 | 10.9 | 10.6 | 10.2 | 10.5 |
| Parental history of premature myocardial infarction, %g | 3,632 / 16.0 | 15.9 | 16.0 | 16.4 | 15.6 |
| History of cancer in first-degree relative | |||||
| Colorectal, % | 3,158 /13.4 | 13.7 | 13.4 | 13.8 | 12.7 |
| Breast cancer, % (women only) | 2,137 / 17.7 | 16.7 | 17.6 | 18.4 | 18.3 |
| Prostate cancer, % (men only) | 1,750 / 15.2 | 15.8 | 14.4 | 15.4 | 15.1 |
| Lung cancer, % | 3,403 / 14.5 | 14.3 | 14.0 | 15.1 | 14.4 |
| Behavioral characteristics, including medication use | |||||
| Smoking, % | 25,488 / 98.5 | ||||
| Current | 1,836 / 7.2 | 7.2 | 7.3 | 7.3 | 7.1 |
| Past | 10,465 / 41.1 | 41.0 | 41.4 | 41.5 | 40.4 |
| Never | 13,187 / 51.7 | 51.9 | 51.3 | 51.3 | 52.5 |
| Leisure-time physical activity and stair climbing, total MET-hours/week, median (interquartile range)h | 15.4 (4.6–31.6) | 15.5 (4.6–31.5) | 15.1 (4.4–31.3) | 15.4 (4.7–31.5) | 15.6 (4.7–32.4) |
| Alcohol use, % | 25365 / 98.0 | ||||
| Never | 7,971 / 31.4 | 30.8 | 31.9 | 31.5 | 31.5 |
| Rarely-<weekly | 1,901 / 7.5 | 7.4 | 7.3 | 7.9 | 7.3 |
| 1–6/week | 8,872 / 35.0 | 36.2 | 34.8 | 33.9 | 35.0 |
| Daily | 6,621 / 26.1 | 25.5 | 26.0 | 26.7 | 26.2 |
| Aspirin use in past month, % | 11,571 / 45.4 | 45.2 | 45.2 | 45.4 | 45.8 |
| Postmenopausal hormone use, % (women only) i | 12,801 / 97.9 | ||||
| Current | 1,481 / 11.6 | 10.7 | 11.7 | 12.3 | 11.6 |
| Past | 5,504 / 43.0 | 43.9 | 42.6 | 42.0 | 43.5 |
| Never | 5,816 / 45.4 | 45.4 | 45.7 | 45.7 | 44.9 |
| Screening behaviors in past 10 years | |||||
| Colonoscopy/sigmoidoscopy, % | 19,327 / 78.4 | 78.7 | 78.4 | 78.9 | 77.7 |
| Prostate-specific antigen test (men only), % | 8,806 / 75.2 | 75.1 | 74.8 | 74.9 | 75.8 |
| Number of mammograms (women only), % | 12,618 / 96.5 | ||||
| 0 | 742 / 5.9 | 6.3 | 6.2 | 4.8 | 6.2 |
| 1–4 | 3,237 / 25.7 | 25.1 | 25.3 | 26.2 | 26.1 |
| ≥5 | 8639 / 68.5 | 68.6 | 68.6 | 69.0 | 67.7 |
| Current use of multivitamins, % | 11,406 / 44.8 | 44.9 | 45.6 | 44.1 | 44.8 |
| Current use of supplemental vitamin D (≤800 IU/dayj), % | 11,030 / 42.6 | 42.3 | 42.7 | 42.7 | 42.8 |
| Current use of supplemental calcium (≤1200 mg/dayk), % | 6,831 / 26.4 | 26.5 | 27.2 | 25.6 | 26.3 |
| Intake of foods related to vitamin D and/or omega-3 fatty acids, mean (SD)l | |||||
| Milk, servings/daym | 0.71 (0.91) | 0.70 (0.90) | 0.71 (0.88) | 0.73 (0.92) | 0.71 (0.92) |
| Other vitamin D-fortified foods, servings/dayn | 0.63 (0.78) | 0.63 (0.82) | 0.63 (0.76) | 0.65 (0.77) | 0.63 (0.77 |
| Dark-meat fish, servings/weeko | 1.05 (1.84) | 1.04 (1.86) | 1.05 (2.01) | 1.06 (1.99) | 1.04 (1.47 |
| Other fish and seafood, servings/weekp | 1.11 (2.32) | 1.11 (2.08) | 1.14 (2.76) | 1.11 (2.60) | 1.09 (1.70 |
P-values for all 4-way comparisons between treatment groups were >0.05.
For categorical variables, this column contains # participants in category / % of nonmissing responses. For continuous variables, this column contains mean (standard deviation) or median (interquartile range) for nonmissing responses. The prevalence of missing responses for all variables ranged from 0 to <5%, except for the following: income (10% missing), parental history of premature myocardial infarction (12.1%), history of cancer in first-degree relative (colorectal, 9.0%; breast, 7.9%; prostate, 10.0%; lung, 9.0%), and PSA test (8.4%).
Race/ethnicity: Non-Hispanic white; African American (whether or not Hispanic); Hispanic (not African American); Asian/Pacific Islander (not Hispanic); American Indian/Alaskan Native (not Hispanic)
Obesity: Body mass index ≥30 kg/m2
Hypertension: Ever diagnosed with high blood pressure or ever use of anti-hypertensive medication
Diabetes: Ever diagnosed with diabetes or current use of anti-diabetic medication
Parental history of premature myocardial infarction: prior to age 60 for father; prior to age 65 for mother
Leisure-time physical activities: walking or hiking; jogging; running; bicycling; aerobic exercise/aerobic dance/exercise machines; lower intensity exercise/yoga/stretching/toning; tennis/squash/racquetball; lap swimming; weight lifting/strength training; other exercise
Virtually all female participants are postmenopausal (>99%).
≤800 IU/day from all supplemental sources of vitamin D combined (individual vitamin D supplements, calcium+vitamin D supplements, medications with vitamin D [e.g., Fosamax Plus D], and multivitamins)
≤1200 mg/day from all supplemental sources of calcium combined
As assessed by a modified version of the Harvard Food Frequency Questionnaire (34).
Milk: Dairy and soy milk
Other vitamin-D fortified foods: vitamin D-fortified cereal, vitamin D-fortified orange juice, yogurt
Dark-meat fish: e.g., mackerel, salmon, sardines, bluefish, swordfish; canned tuna p.
Other fish and seafood: e.g., cod, haddock, halibut; breaded fish cakes, pieces, or fish sticks; shrimp, lobster, scallops