Data from Night Shift Work and Risk of Melanoma: A Prospective Cohort Study among 59,384 Female Nurses in the Netherlands

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