Clinically the prevalence of signifcant lower urinary tract symptoms and/or poor flow rises from around 13% in the 5th decade of life to between 28–43% by the 7th and 8th decades of life. Histologically, benign prostatic hypertrophy is seen on autopsy from the age of 30 years with 88% of those beyond 80 years old afected. The risk of urinary retention in the 8th decade of life is between 0.9–3.4% per year for symptomatic men.