Night shift work and risk of melanoma: a prospective cohort study among 59,384 female nurses in the Netherlands

Abstract

Background: Night shift work may be a risk factor for Results: During 10 years of follow-up, 307 women developed melanoma, potentially due to suppressed melatonin and de- melanoma. Melanoma risk did not differ between women who creased vitamin D levels. We examine the potential association worked night shifts and those who never worked night shifts between night shift work and melanoma risk using detailed, (age-adjusted HR ¼ 0.98; 95% confidence interval, 0.73–1.30). No lifetime information on night shift work in a large cohort of statistically significantly increased risks were found for a longer Dutch nurses. night shift work duration, a higher cumulative number of nights Methods: We used questionnaire data from the Nightin- worked, a higher number of consecutive nights worked per gale Study obtained from 59,384 (former) female nurses month, or a shorter time since quitting night shift work. ages 19 to 65 years (median: 48.7; IQR: 39.6–55.3). HRs and Conclusions: We found no association between night shift 95% confidence intervals for melanoma risk in relation to work exposure and melanoma risk. various lifetime night shift work exposure variables were Impact: This study should reassure nurses that working night estimated. shifts is not associated with an increased risk of melanoma.