Gender differences, UV exposure and risk of lentigo maligna in a nationwide healthcare population cohort study

Background Our understanding of the relationship between ultraviolet (UV) radiation exposure and lentigo maligna (LM) has been largely derived from epidemiologic/clinical studies based on invasive melanoma. Recent studies have shown gender differences in melanocytic tumours incidence. Objective To examine the association of UV light with LM by gender remains unclear. Methods Two prospective cohort study [Nurses’ Health Study (1980–2012)] and [Health Professionals Follow‐up Study (1986–2010)] were analysed. All participants with LM or MIS, non‐LM type were included in analysis. UV index at birth, age 15, and age 30 were calculated by gender. Lifetime UV flux was calculated. Hazard ratios (HRs) were calculated. Results A total of 110 485 women from NHS and 41 015 men from HPFS were examined. A total of 281 LM and 776 melanoma in situ (MIS), non‐LM cases were reported. Risk of LM increased with increasing UV flux exposure in multivariate‐adjusted models for men (P for trend = 0.04), but not for women (P for trend = 0.91). Conclusions UV flux may be associated with LM in men but not in women.