Table 1. Age-standardized characteristics of the Health Professionals Follow-up Study at baseline in 1987 by categories of sleep duration.
| Sleep Duration Categories | ||||||
|---|---|---|---|---|---|---|
|
| ||||||
| Characteristic | <=5 hours (n=701) |
6 hours (n=6,257) |
7 hours (n=15,220) |
8 hours (n=8,328) |
9 hours (n=1,432) |
10+ hours (n=203) |
| Mean age, y* | 58 | 55 | 55 | 57 | 61 | 64 |
| Mean BMI, kg/m2 | 25.8 | 25.4 | 25.2 | 25.3 | 25.5 | 25.9 |
| White race, % | 93 | 94 | 97 | 97 | 97 | 88 |
| Former smoker, quit > 10 years ago | 28 | 30 | 31 | 30 | 30 | 31 |
| Former smoker, quit ≤ 10 years ago | 11 | 12 | 12 | 13 | 15 | 18 |
| Current smoker | 9 | 8 | 8 | 9 | 11 | 15 |
| Married, % | 84 | 89 | 91 | 91 | 90 | 91 |
| Currently working, % | 89 | 88 | 87 | 84 | 78 | 75 |
| Vigorous activity (% highest quintile) | 18 | 17 | 15 | 14 | 10 | 10 |
| Family history of prostate cancer, % | 15 | 13 | 13 | 14 | 14 | 5 |
| History of diabetes, % | 4 | 3 | 3 | 3 | 4 | 7 |
| Snoring regularly, % | 28 | 28 | 27 | 28 | 27 | 33 |
| Current beta-blocker users, % | 11 | 10 | 9 | 10 | 13 | 16 |
| Current multivitamin user, % | 44 | 42 | 41 | 40 | 39 | 34 |
| Antidepressant user, 1990, % | 3 | 2 | 2 | 2 | 2 | 7 |
| 2+ times urinate at night, 1992, % | 21 | 22 | 22 | 24 | 31 | 35 |
| PSA test, 1994, % | 40 | 44 | 43 | 42 | 38 | 30 |
| PSA test, 2006, % | 67 | 70 | 72 | 72 | 70 | 60 |
| Coffee intake, 3+ cups/day, % | 11 | 11 | 10 | 9 | 10 | 6 |
| Mean dietary intakes | ||||||
| Total calories, kcal/day | 1907 | 1917 | 1952 | 1976 | 2012 | 2004 |
| Alcohol use, g/day | 9.7 | 10.1 | 10.8 | 12.4 | 15.0 | 18.6 |
| Vitamin E, mg/day | 48.2 | 39.9 | 36.7 | 34.1 | 29.9 | 32.1 |
*
All variables (except age) are standardized to the age distribution of the cohort at baseline.
BMI = body mass index; PSA = prostate-specific antigen