Table 1. Baseline characteristics of study participants by smoking statusa.
| Smoking status | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
|
|||||||||
| Women (NHS, 1976–2008) | Women (NHS II, 1989–2007) | Men (HPFS, 1986–2008) | |||||||
|
| |||||||||
| Never (n=50,897) |
Former (n=27,065) |
Current (n=38,604) |
Never (n=60,932) |
Former (n=19,835) |
Current (n=11,884) |
Never (n=20,911) |
Former (n=18,384) |
Current (n=4,521) |
|
| Age,y | 42.7 (7.4) | 43.0 (7.1) | 42.8 (7.1) | 34.3 (4.7) | 34.7 (4.4) | 34.5 (4.6) | 52.6 (9.6) | 55.3 (9.5) | 53.9 (9.1) |
| Married/Partnership (%) | 94.1 | 93.7 | 91.1 | 79.5 | 79.7 | 67.7 | 91.3 | 91.8 | 85.3 |
| Current menopausal hormones (%) | 6.1 | 6.7 | 6.8 | 3.6 | 3.6 | 4.6 | na | na | na |
| Minor tranquilizers (%) | 3.0 | 3.9 | 4.2 | 1.3 | 1.9 | 2.7 | 0.6 | 0.9 | 1.4 |
| Antidepressants (%) | 5.6 | 6.6 | 7.5 | 12.7 | 16.9 | 20.9 | 0.9 | 1.1 | 1.6 |
| BMI (%)b | |||||||||
| < 25 kg/m2 | 68.4 | 70.5 | 75.6 | 70.6 | 70.3 | 69.3 | 51.5 | 45.3 | 48.7 |
| 25–29.9 kg/m2 | 21.3 | 19.8 | 17.6 | 18.2 | 18.7 | 19.1 | 41.6 | 46.0 | 43.9 |
| ≥ 30 kg/m2 | 9.3 | 8.7 | 5.9 | 11.2 | 11.0 | 11.6 | 6.9 | 8.7 | 7.3 |
| Diet intakec | |||||||||
| Caffeinated coffee, cups/dayd | 1.4 (1.8) | 1.8 (1.9) | 2.2 (2.2) | 0.9 (1.3) | 1.6 (1.5) | 2.2 (1.9) | 1.0 (1.4) | 1.5 (1.6) | 2.1 (1.9) |
| Caffeine, mg/daye | 256 (260) | 303 (278) | 352 (321) | 197 (190) | 278 (214) | 384 (257) | 181 (202) | 252 (234) | 337 (274) |
| Alcohol intake, g/day | 4.0 (7.8) | 7.5 (10.6) | 8.7 (12.9) | 2.3 (4.8) | 4.3 (6.9) | 5.0 (8.9) | 8.0 (12.1) | 13.7 (16.5) | 17.4 (20.2) |
| ≥30 g/day (%) | 1.7 | 4.0 | 6.7 | 0.5 | 1.5 | 2.9 | 6.2 | 14.5 | 24.1 |
Abbreviations: HPFS, Health Professionals Follow-up Study; NHS, Nurses' Health Study.
a
Values are reported as mean (SD) unless otherwise indicated. Means and percentages are standardized to the age distribution of the study population. Coffee and caffeine consumption were computed as the cumulative average of intake.
b
The body-mass index is the weight in kilograms divided by the square of the height in meter.
c
Information on diet was obtained in 1980 for the NHS, 1991 for the NHS II, and 1986 for the HPFS.
d
One cup= 8 oz or 237 ml.
e
Caffeine was calculated from coffee and non-coffee sources (tea, caffeinated soft drink, chocolate).