Associations of self-reported sleep duration and snoring with colorectal cancer risk in men and women.

OBJECTIVE

We assessed the relationship between sleep duration, snoring and colorectal cancer risk.

METHODS

Prospective cohort studies.

METHODS

United States.

METHODS

A total of 30,121 men aged 41 to 79 years in the Health Professionals Follow-up Study and 76,368 women aged 40 to 73 years in the Nurses' Health Study.

METHODS

None.

RESULTS

We queried information on sleep duration and snoring in 1986/87. Cox proportional hazards regression models were used to estimate multivariable hazard ratios (HRs, 95% CIs). We documented 1,973 incident colorectal cancer cases (709 men and 1,264 women) over a 22-year follow-up period. Compared to sleep an average 7 h, ≥ 9 h of sleep was significantly associated with a higher risk of colorectal cancer among men (HR = 1.35, 95% CI: 1.00, 1.82), and to a lesser degree, among women (HR = 1.11, 95% CI: 0.85, 1.44). The risk associated with longer sleep was restricted to individuals who regularly snored (men: HR = 1.80, 95% CI: 1.14, 2.84; women: HR = 2.32, 95% CI: 1.24, 4.36) and to overweight individuals (i.e., BMI ≥ 25 kg/m2) (men: HR = 1.52, 95% CI: 1.04, 2.21; women: HR = 1.37, 95% CI: 0.97, 1.94). Short sleep duration (≤ 5 h) was not associated with an increased risk of colorectal cancer in the entire sample or in subgroups stratified by snoring or BMI.

CONCLUSIONS

Longer sleep duration was associated with an increased risk of developing colorectal cancer among individuals who were overweight or snored regularly. This observation raises the possibility that sleep apnea and its attendant intermittent hypoxemia may contribute to cancer risk.