Prostate disorders and cancer Quiz: Ace Your Exams

A 68-year-old man comes to the office because of weak urinary stream. He has been experiencing this for the past year, but it has been gradually worsening, and he now has to strain to urinate. He also complains of urinary frequency and urgency but denies incontinence or pain with micturition. He was recently treated for a presumed urinary tract infection with antibiotics for 2 weeks. Past medical history is significant for type II diabetes mellitus and hypertension. Medications include metformin and hydrochlorothiazide. He has smoked a pack of cigarettes daily for 20 years. Vitals are within normal limits. Digital rectal examination shows a symmetrically enlarged, smooth, firm, non-tender prostate with a rubbery texture. The rest of the examination is noncontributory. The most recent HbA1c 2 months ago was 5.6% (reference range: less than or equal to 6%). Urinalysis at this visit is as follows:  

Prostate specific antigen is 5.5 ng/mL (reference range: 1-1.5 ng/mL). Which of the following factors in the patient’s history is the strongest predisposing factor for this condition?