A short-term increase in cancer risk associated with daytime napping is likely to reflect pre-clinical disease: prospective cohort study.
Br J Cancer
; 107(3): 527-30, 2012 Jul 24.
Article
in En
| MEDLINE
| ID: mdl-22782344
ABSTRACT
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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Breast Neoplasms
/
Neoplasms
Type of study:
Etiology_studies
/
Incidence_studies
/
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Limits:
Female
/
Humans
/
Middle aged
Country/Region as subject:
Europa
Language:
En
Journal:
Br J Cancer
Year:
2012
Type:
Article
Affiliation country:
United kingdom