Table 1.
Baseline Characteristics of Study Participants by Caffeinated Coffee Consumptiona
| Caffeinated Coffee Consumption (cupsb)
|
|||||||||
|---|---|---|---|---|---|---|---|---|---|
| Women (NHS, 1992–2008) | Women (NHS II, 1993–2007) | Men (HPFS, 1988–2008) | |||||||
|
| |||||||||
| ≤1/week (n=17,049) |
1/day (n=20,134) |
≥4/day (n=6,894) |
≤1/week (n=41,459) |
1/day (n=11,633) |
≥4/day (n=8,121) |
≤1/week (n=17,910) |
1/day (n=5,646) |
≥4/day (n=4,769) |
|
| Age (y) | 57.5±7.4 | 58.6±7.1 | 57.6±6.7 | 37.6±4.8 | 38.3±4.6 | 39.6±4.3 | 55.3±9.7 | 56.0±9.7 | 54.3±8.6 |
| Physical activity (MET-hr/wk) | 19.5±23.6 | 19.4±23.5 | 18.1±23.2 | 20.2±26.0 | 21.8±27.9 | 21.2±30.0 | 30.3±34.6 | 29.9±32.6 | 27.9±31.9 |
| Body-mass index (kg/m2) | 26.4±5.4 | 26.1±5.0 | 25.9±4.8 | 24.9±5.7 | 24.3±5.1 | 24.7±5.0 | 25.3±3.2 | 25.5±3.2 | 25.9±3.1 |
| Past smoker (%) | 32.1 | 43.2 | 36.5 | 16.0 | 26.3 | 26.4 | 32.2 | 41.0 | 45.6 |
| Current smoker (%) | 7.4 | 11.2 | 32.8 | 6.6 | 9.8 | 35.4 | 6.0 | 8.7 | 20.0 |
| Married/Partnership (%) | 71.1 | 73.5 | 57.1 | 73.3 | 72.8 | 65.9 | 70.3 | 70.4 | 68.6 |
| Current menopausal hormones (%) | 28.2 | 29.5 | 21.7 | 4.7 | 4.4 | 4.6 | na | na | na |
| Minor tranquilizers (%) | 2.7 | 2.3 | 1.7 | 1.7 | 1.7 | 1.8 | 1.0 | 0.8 | 0.8 |
| Antidepressants (%) | 7.1 | 6.3 | 5.4 | 14.4 | 14.1 | 16.9 | 1.0 | 1.1 | 1.3 |
| Diet intakec | |||||||||
| Caffeine (mg/day)d | 81±84 | 234±159 | 684±174 | 80±76 | 199±58 | 733±113 | 53±69 | 190±56 | 723±113 |
| Decaffeinated coffee (cups/day) | 0.5±1.0 | 0.9±1.2 | 0.4±1.1 | 0.3±0.8 | 0.5±0.8 | 0.2±0.7 | 0.7±1.2 | 0.7±1.2 | 0.3±0.8 |
| Tea (cups/day) | 1.1±1.5 | 0.6±1.0 | 0.3±0.8 | 0.8±1.3 | 0.6±1.0 | 0.5±1.0 | 0.5±0.9 | 0.5±0.8 | 0.4±0.9 |
| Alcohol intake (g/day) | 3.3±7.8 | 5.5±9.5 | 5.8±10.4 | 1.9±4.6 | 3.5±5.7 | 4.5±7.8 | 8.5±13.6 | 12.0±14.7 | 15.0±18.8 |
| ≥30 g/day (%) | 2.3 | 3.4 | 4.6 | 0.5 | 0.8 | 2.3 | 7.6 | 11.0 | 18.0 |
Abbreviations: HPFS, Health Professionals Follow-up Study; NHS, Nurses’ Health Study; MET, metabolic equivalents of task.
a
Values are reported as mean±SD unless otherwise indicated. Means and percentages are standardized to the age distribution of the study population. Coffee consumption was computed as the cumulative average of intake, but not including changes in intake during the 2-year preceding follow-up periods.
b
One cup= 8 oz or 237 ml.
c
Information on diet was obtained in 1990 for the NHS, 1991 for the NHS II, and 1986 for the HPFS.
d
Caffeine was calculated from coffee and non-coffee sources (tea, caffeinated soft drink, chocolate).