Table 1. Multivariate relative risks (RR) and 95% confidence intervals (CI) of endometrial cancer in relation to time spent sitting per day and joint categories of sitting and vigorous intensity physical activity among 69 648 women in the NIH-AARP Diet and Health Study.
|
Time spent sitting per day
|
||||||
|---|---|---|---|---|---|---|
| <3 h | 3–4 h | 5–6 h | 7–8 h | 9+ h | P trend | |
| All women | ||||||
| No. of cases | 150 | 232 | 274 | 152 | 80 | |
| Multivariatea RR (95% CI) | 1.0 (ref) | 1.15 (0.94, 1.42) | 1.48 (1.22, 1.81) | 1.61 (1.28, 2.02) | 1.59 (1.21, 2.10) | <0.01 |
| Multivariateb RR (95% CI) | 1.0 (ref) | 1.13 (0.92, 1.39) | 1.43 (1.17, 1.75) | 1.52 (1.21, 1.91) | 1.45 (1.10, 1.92) | <0.01 |
| Multivariatec RR (95% CI) | 1.0 (ref) | 1.07 (0.87, 1.32) | 1.29 (1.05, 1.57) | 1.33 (1.05, 1.67) | 1.15 (0.87, 1.53) | <0.01 |
| Actived women | ||||||
| No. of cases | 74 | 94 | 97 | 51 | 16 | |
| Multivariateb RR (95% CI) | 1.0 (ref) | 1.04 (0.77, 1.42) | 1.34 (0.99, 1.81) | 1.54 (1.07, 2.21) | 1.19 (0.69, 2.05) | <0.01 |
| Multivariatec RR (95% CI) | 1.0 (ref) | 0.99 (0.73, 1.35) | 1.22 (0.90, 1.66) | 1.37 (0.96, 1.97) | 0.98 (0.57, 1.70) | 0.08 |
| Inactive women | ||||||
| No. of cases | 76 | 138 | 177 | 101 | 64 | |
| Multivariateb RR (95% CI) | 1.0 (ref) | 1.21 (0.92, 1.61) | 1.51 (1.16, 1.98) | 1.55 (1.15, 2.10) | 1.60 (1.14, 2.24) | <0.01 |
| Multivariatec RR (95% CI) | 1.0 (ref) | 1.14 (0.86, 1.51) | 1.35 (1.03, 1.76) | 1.33 (0.99, 1.80) | 1.25 (0.89, 1.76) | 0.04 |
| Joint effects of vigorous physical activity and sitting time | ||||||
| Active women | 1.0 (ref) | 1.04 (0.77, 1.42) | 1.34 (0.99, 1.81) | 1.55 (1.08, 2.21) | 1.19 (0.69, 2.05) | |
| Inactive women | 1.35 (0.94, 1.93) | 1.63 (1.18, 2.26) | 2.03 (1.48, 2.79) | 2.09 (1.49, 2.93) | 2.14 (1.48, 3.10) | |
Multivariate models are adjusted for age (continuous), race (white vs other/unknown), smoking status (never, former, current or unknown), parity (nulliparous, one, two, ⩾three births or unknown), ever use of contraceptives (no, yes, unknown), age at menopause (premenopausal, natural menopause at <45, 45–49, 50–54, or ⩾55 years of age or unknown age at menopause), and hormone therapy formulation (never used, estrogen therapy use, estrogen plus progestin therapy use or unknown hormone therapy use).
Relative risks are additionally adjusted for level of vigorous physical activity (never/rarely, 1–3 times/month, 1–2 times/week, 3–4 times/week, 5+ times/week).
Relative risks are further adjusted for body mass index.
Active women are those who engaged in vigorous physical activity for a bout of 20 or more minutes at least three times per week. Inactive women did vigorous physical activity fewer than three times per week.