A short-term increase in cancer risk associated with daytime napping is likely to reflect pre-clinical disease: prospective cohort study

作者：Cairns B J^*; Travis R C; Wang X S; Reeves G K; Green J; Beral V

来源：British Journal of Cancer, 2012, 107(3): 527-530.

DOI：10.1038/bjc.2012.291

• daytime napping
• sleep disturbance
• breast cancer
• reverse causation
• pre-clinical cancer

BACKGROUND: Sleep disturbance, a correlate of which is daytime napping, has been hypothesised to be associated with risk of breast and other cancers.
METHODS: We estimated relative risks (RR) of breast and other invasive cancers by the reported frequency of daytime napping in a large prospective cohort of middle-aged women in the UK.
RESULTS: During an average of 7.4 years of follow-up, 20 058 breast cancers and 31 856 other cancers were diagnosed. Over the first 4 years of follow-up, daytime napping (sometimes/usually vs rarely/never) was associated with slightly increased risks of breast cancer (RR = 1.10, 95% CI 1.06-1.15) and of other cancers (RR = 1.12, 1.08-1.15), but the RRs decreased significantly with increasing follow-up time (P = 0.001 and P = 0.01, respectively, for trend). Four or more years after baseline, there was no elevated risk of breast cancer (RR = 1.00, 0.96-1.05), and only marginally greater risk of other cancers (RR = 1.04, 1.01-1.07).
CONCLUSION: The effect of pre-clinical disease is a likely explanation for the short-term increased risk of breast and other cancers associated with daytime napping. British Journal of Cancer (2012) 107, 527-530. doi: 10.1038/bjc.2012.291 www.bjcancer.

• 出版日期2012-7-24