Table 3b.
Risk of breast cancer associated with chronotype: results from logistic regression analysis among 39334 California Teacher Study participants, excluding cases who were diagnosed within two years of completing the Q5 questionnaire (n=352).
| Chronotype | # cases | Crude Odds Ratio a | 95% CI | Multivariate Adjusted Odds Ratiob | 95% CI |
|---|---|---|---|---|---|
| Definite morning | 844 | 1.00 | – | 1.00 | – |
| More morning than evening | 492 | 1.09 | 0.97 – 1.22 | 1.08 | 0.96 – 1.21 |
| Neither morning/evening | 336 | 1.11 | 0.98 – 1.27 | 1.09 | 0.96 – 1.25 |
| More evening than morning | 359 | 1.09 | 0.96 – 1.24 | 1.07 | 0.94 – 1.22 |
| Definite evening type | 336 | 1.20 | 1.05 – 1.37 | 1.16 | 1.02 – 1.33 |
a
Adjusted for age
b
Adjusted for age, race, family history of breast cancer, age at menarche, smoking pack-years, BMI, alcohol consumption, physical activity, age at first full-term pregnancy, breast feeding history, age at menopause, ever use of hormone therapy.