A population-based cohort study on sun habits and endometrial cancer.
BACKGROUND
No large cohort study has examined the risk of endometrial cancer in relation to sun exposure.


METHODS
A population-based cohort study of 29,508 women who answered a questionnaire in 1990-92, of whom 24,098 responded to a follow-up enquiry in 2000-02. They were followed for an average of 15.5 years.


RESULTS
Among the 17,822 postmenopausal women included, 166 cases of endometrial cancer were diagnosed. We used a multivariate Cox regression analysis adjusting for age and other selected demographic variables to determine the risk of endometrial cancer. Women using sun beds >3 times per year reduced their hazard risk (HR) by 40% (0.6, 95% confidence interval (CI) 0.4-0.9) or by 50% when adjusting for body mass index or physical activity (HR 0.5, 95% CI 0.3-0.9), and those women who were sunbathing during summer reduced their risk by 20% (HR 0.8 95% CI 0.5-1.5) compared with women who did not expose themselves to the sun or to artificial sun (i.e., sun beds).


CONCLUSIONS
Exposure to artificial sun by the use of sun beds >3 times per year was associated with a 40% reduction in the risk of endometrial cancer, probably by improving the vitamin D levels during winter.
Epstein
E
E
Department of Obstetrics and Gynaecology, Institute of Clinical Sciences Lund, Lund University Hospital, 221 85 Lund, Sweden. elisabeth.epstein@med.lu.se
Lindqvist
P G
PG
Geppert
B
B
Olsson
H
H
D000328:Adult; D015331:Cohort Studies; D016889:Endometrial Neoplasms / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D012307:Risk Factors; D013472:Sunlight; D014807:Vitamin D / Q000008:administration & dosage
D014807:Vitamin D