KLK3 and obesity due to melanocortin 4 receptor deficiency: Although different times of adoption of prostate-specific antigen (PSA) as a screening tool in different countries may partly explain the discrepant trends observed in different ethnicities, genetic variations and changes in the prevalence of risk factors such as population aging and changes in dietary patterns with increasing rates of animal fat consumption and lifestyle changes with less physical activity and lack of exercise leading to obesity etc. are also possible explanations (2).