Table 1.
Age standardised baseline characteristics (1990) according to physical inactivity, Nurses’ Health Study (n=69 950). Figures are percentages of participants unless stated otherwise
| Amount of time sitting (2=lowest, 6=highest)* | |||||
|---|---|---|---|---|---|
| 2 | 3 | 4 | 5 | 6 | |
| No of participants | 12 451 | 20 718 | 24 549 | 10 403 | 1829 |
| Mean age in 1990 | 56.6 (7.2) | 56.0 (7.1) | 56.0 (7.1) | 56.0 (7.0) | 59.0 (6.9) |
| Amount of time sitting in 1988 (hours/week): | |||||
| <10 | 100 | 36 | 2 | 0 | 0 |
| 11-40 | 0 | 64 | 81 | 12 | 0 |
| ≥41 | 0 | 0 | 17 | 88 | 100 |
| Amount of time sitting at home in 1990 (hours/week): | |||||
| <10 | 100 | 64 | 17 | 0 | 0 |
| 11-40 | 0 | 36 | 81 | 88 | 0 |
| ≥41 | 0 | 0 | 2 | 12 | 100 |
| White race/ethnicity | 96 | 98 | 98 | 99 | 98 |
| Smoking: | |||||
| Non-smokers | 45 | 45 | 46 | 43 | 42 |
| Ex-smokers | 37 | 39 | 40 | 42 | 41 |
| Current smokers | 18 | 16 | 14 | 15 | 17 |
| Missing | 0.3 | 0.2 | 0.1 | 0.2 | 0.1 |
| Pack years among ever smokers†‡ | 23 | 22 | 23 | 24 | 30 |
| Spouse’s educational attainment: | |||||
| High school | 36 | 36 | 38 | 37 | 41 |
| College | 23 | 24 | 24 | 24 | 23 |
| Graduate school | 18 | 20 | 20 | 21 | 21 |
| Missing | 23 | 20 | 18 | 18 | 15 |
| Body mass index (BMI) | 25.3 | 25.5 | 25.6 | 26.3 | 27.3 |
| Total physical activity (metabolic equivalents/week)†§ | 19.6 | 19.7 | 19.7 | 17.8 | 15.7 |
| Total caloric intake (kilocalories/day)† | 1682 | 1722 | 1783 | 1803 | 1840 |
| Parity: | |||||
| Nulliparous | 5 | 5 | 6 | 6 | 7 |
| 1 | 7 | 7 | 7 | 7 | 8 |
| 2-3 | 55 | 55 | 56 | 57 | 52 |
| ≥4 | 31 | 32 | 30 | 29 | 32 |
| Missing | 2 | 1 | 1 | 1 | 1 |
| Premenopausal | 21 | 23 | 23 | 23 | 12 |
| Hormone replacement therapy after menopause: | |||||
| None | 27 | 26 | 26 | 27 | 32 |
| Past user | 16 | 15 | 15 | 14 | 20 |
| Current user of oestrogen replacement therapy | 13 | 13 | 13 | 13 | 14 |
| Current user of oestrogen-progesterone replacement therapy | 9 | 9 | 10 | 10 | 9 |
| Missing | 14 | 14 | 13 | 13 | 13 |
| Use of NSAIDs | 43 | 45 | 44 | 44 | 42 |
| Warfarin use | 0.9 | 0.8 | 0.9 | 0.9 | 2 |
| Multivitamin supplement use | 37 | 38 | 38 | 39 | 39 |
| Hypertension | 18 | 18 | 18 | 20 | 25 |
| Coronary heart disease¶ | 1 | 3 | 3 | 3 | 5 |
| Rheumatological disease** | 3 | 3 | 3 | 3 | 4 |
| Dietary intake (servings/day)†: | |||||
| Fruits | 1.7 | 1.7 | 1.7 | 1.6 | 1.5 |
| Vegetables | 3.5 | 3.5 | 3.4 | 3.4 | 3.3 |
| Fish | 0.36 | 0.36 | 0.35 | 0.34 | 0.32 |
| Whole grain cereals | 1.3 | 1.3 | 1.4 | 1.4 | 1.4 |
| Refined grain cereals | 1.1 | 1.2 | 1.2 | 1.3 | 1.4 |
| Cured meat | 0.19 | 0.21 | 0.22 | 0.24 | 0.28 |
| Dessert | 0.9 | 1.0 | 1.1 | 1.1 | 1.2 |
| Chips (French fries) | 0.04 | 0.04 | 0.05 | 0.05 | 0.06 |
NSAIDs=non-steroidal anti-inflammatory drugs.
*Data describing amount of time sitting available from 1988 and 1990 questionnaires. See text for details describing categories of physical activity.
†Age adjusted mean (all such values).
‡No of packs smoked/day×No of years smoked, among past and current smokers.
§Metabolic equivalent hours/week, sum of average time/week spent in each activity×metabolic equivalent value of each activity.
¶Coronary heart disease includes any history of myocardial infarction, coronary artery stenosis, or angina.
**Includes any history of systemic lupus erythematosis or rheumatoid arthritis.