Obesity is associated with increased risk of invasive penile cancer

Background: To validate the association between obesity and penile cancer at a population level, we conducted a matched case-control study linking the Iowa Department of Motor Vehicles Drivers' License Database (DLD) with cancer surveillance data collected by the State Health Registry of Iowa (SHRI). Methods: All men diagnosed with invasive penile squamous cell carcinoma from 1985 to 2010 were identified by SHRI. Two hundred sixty-six cancer cases and 816 cancer-free male controls, selected from the Iowa DLD, were matched within 5-year age and calendar year strata. Body mass index (BMI) was calculated using self- reported height and weight from the DLD. Results: Conditional logistic regression was used to evaluate the association between BMI and the risk of developing invasive penile cancer. Obesity was significantly associated with an increased risk of developing penile cancer. For every five-unit increase in BMI the risk of invasive penile cancer increased by 53 % (OR 1.53, 95 % CI 1.29-1.81, p < 0.0001). Conclusion: We previously reported an association between obesity and higher risk of invasive penile cancer and advanced cancer stage at diagnosis in a hospital-based retrospective study. This population-based study confirms an association between obesity and invasive penile cancer.