Table 1.
Age and Age-adjusted Characteristics of 7,813 Women in the Nurses’ Health Study by Total Physical Activity Reported in 1988a,b
| Characteristic | Total Activity in 1988, MET-hours/weekc |
P Valued | |||||
| <3 (n = 1,605) |
9–<18 (n = 1,680) |
≥27 (n = 1,337) |
|||||
| % | Mean (SD) | % | Mean (SD) | % | Mean (SD) | ||
| Age at blood collection, yearse | 58.5 (6.7) | 59.1 (6.6) | 59.5 (6.5) | <0.001 | |||
| Ever oral contraceptive use | 42.8 | 44.2 | 41.8 | 0.57 | |||
| Nulliparous | 5.4 | 6.0 | 7.2 | 0.33 | |||
| Parity, no. of childrenf | 3.2 (1.7) | 3.1 (1.7) | 3.0 (1.7) | 0.08 | |||
| Age at menarche, years | 12.5 (1.4) | 12.6 (1.3) | 12.7 (1.5) | 0.01 | |||
| Postmenopausal | 83.5 | 82.1 | 81.6 | 0.08 | |||
| Age at menopause, years | 50.2 (7.7) | 50.5 (7.7) | 50.1 (7.3) | 0.74 | |||
| Postmenopausal hormone use | |||||||
| Never | 45.9 | 40.3 | 40.1 | <0.001 | |||
| Past | 17.0 | 16.5 | 15.0 | 0.18 | |||
| Current | 36.6 | 42.6 | 44.1 | <0.001 | |||
| Smoking status | |||||||
| Never | 43.9 | 45.3 | 41.3 | 0.40 | |||
| Past | 35.9 | 40.7 | 46.5 | <0.001 | |||
| Current | 20.1 | 13.9 | 11.7 | <0.001 | |||
| Body mass index at age 18 yearsg | 21.6 (3.3) | 21.4 (2.9) | 21.3 (2.7) | 0.04 | |||
| Body mass index at blood collectiong | 26.6 (5.7) | 25.3 (4.5) | 24.8 (4.4) | <0.001 | |||
| Waist circumference, cm | 62.8 (36.5) | 62.6 (33.0) | 64.2 (31.1) | 0.31 | |||
| Waist/hip ratio | 0.8 (0.1) | 0.8 (0.1) | 0.8 (0.08) | <0.001 | |||
| Weight gain since age 18 years, kg | 13.3 (13.1) | 10.5 (11.2) | 9.4 (11.1) | <0.001 | |||
| Energy intake, kcal/day | 1,754.5 (529.4) | 1,765.2 (508.4) | 1,797.9 (518.7) | 0.008 | |||
| Total sitting in 1992, hours/week | 39.0 (23.7) | 38.3 (22.6) | 35.7 (22.0) | <0.001 | |||
| Total activity in 1988, MET-hours/week | 1.4 (0.9) | 12.9 (2.7) | 46.0 (18.4) | ||||
Abbreviations: MET-hours/week, metabolic equivalent hours of activity/week; SD, standard deviation.
a
Values are standardized to the age distribution of the study population at blood collection.
b
Values may not add to 100% because of missing data.
c
Lowest, middle, and highest categories of total activity are presented.
d
Two-sided P values were calculated by using multivariate linear regression adjusted for age.
e
Value not age adjusted.
f
Among parous women.
g
Body mass index: weight (kg)/height (m)2.