Sleep quality and breast cancer risk in a cohort of Finnish women, 1976 to 1996
| . | No. of women (n = 12,084) . | No. of breast cancers . | Age-adjusted HR (95% CI) . | Multivariable HR (95% CI)* . | ||||
|---|---|---|---|---|---|---|---|---|
| Sleep quality in 1975, follow-up 1976 to 1996 | ||||||||
| Good | 5,245 | 103 | 1.00 | 1.00 | ||||
| Fairly good | 5,803 | 113 | 0.84 (0.64-1.10) | 0.84 (0.63-1.12) | ||||
| Fairly poor | 787 | 16 | 0.66 (0.39-1.13) | 0.78 (0.45-1.35) | ||||
| Poor | 249 | 8 | 0.99 (0.47-2.07) | 1.15 (0.54-2.43) | ||||
| P for linear trend (categorical) | 0.21 | 0.52 | ||||||
| Subjects with the same sleep quality in 1975 and 1981, follow-up 1976 to 1996 | ||||||||
| Good | 3,047 | 56 | 1.00 | 1.00 | ||||
| Fairly good | 3,270 | 70 | 0.95 (0.67-1.35) | 0.91 (0.62-1.32) | ||||
| Fairly poor | 219 | 5 | 0.75 (0.30-1.90) | 0.89 (0.35-2.27) | ||||
| Poor | 58 | 3 | 1.58 (0.45-5.52) | 1.87 (0.52-6.73) | ||||
| P for linear trend (categorical) | 0.92 | 0.97 | ||||||
| . | No. of women (n = 12,084) . | No. of breast cancers . | Age-adjusted HR (95% CI) . | Multivariable HR (95% CI)* . | ||||
|---|---|---|---|---|---|---|---|---|
| Sleep quality in 1975, follow-up 1976 to 1996 | ||||||||
| Good | 5,245 | 103 | 1.00 | 1.00 | ||||
| Fairly good | 5,803 | 113 | 0.84 (0.64-1.10) | 0.84 (0.63-1.12) | ||||
| Fairly poor | 787 | 16 | 0.66 (0.39-1.13) | 0.78 (0.45-1.35) | ||||
| Poor | 249 | 8 | 0.99 (0.47-2.07) | 1.15 (0.54-2.43) | ||||
| P for linear trend (categorical) | 0.21 | 0.52 | ||||||
| Subjects with the same sleep quality in 1975 and 1981, follow-up 1976 to 1996 | ||||||||
| Good | 3,047 | 56 | 1.00 | 1.00 | ||||
| Fairly good | 3,270 | 70 | 0.95 (0.67-1.35) | 0.91 (0.62-1.32) | ||||
| Fairly poor | 219 | 5 | 0.75 (0.30-1.90) | 0.89 (0.35-2.27) | ||||
| Poor | 58 | 3 | 1.58 (0.45-5.52) | 1.87 (0.52-6.73) | ||||
| P for linear trend (categorical) | 0.92 | 0.97 | ||||||
Adjusted for the effects of age, zygosity, social class, number of children, use of oral contraceptives, body mass index, alcohol use, smoking, and physical activity.