Marriage, cohabitation and incidence trends of invasive penile squamous cell carcinoma in Denmark 1978–2010

Few population‐based studies have investigated the relation between living arrangements and risk of invasive penile squamous cell carcinoma (iP‐SCC). Using long‐term national cancer registry data in Denmark we examined incidence trends of iP‐SCC. Furthermore, we examined the relation between marital status, cohabitation status and risk of iP‐SCC using hazard ratios (HRs) with 95% confidence intervals (CIs) obtained in Cox proportional hazards regression analyses as our measure of relative risk. Overall, 1,292 cases of iP‐SCC were identified during 65.6 million person‐years of observation between 1978 and 2010. During this period, the WHO world age‐standardized incidence remained relatively stable (p‐trend = 0.41) with an average incidence of 1.05 cases per 100,000 person‐years. When compared to married men, those who were unmarried (HR 1.37; 95% CI: 1.13–1.66), divorced (HR 1.49; 95% CI: 1.24–1.79) or widowed (HR 1.36; 95% CI: 1.13–1.63) were at increased risk of iP‐SCC. Regarding cohabitation status, single‐living men were at increased risk of iP‐SCC compared to men in opposite‐sex cohabitation (HR 1.43; 95% CI: 1.26–1.62). Risk increased with increasing numbers of prior opposite‐sex (p‐trend = 0.02) and same‐sex (p‐trend