Objective: To examine the effect of cigarette smoking (CS) status and total testosterone (TT) levels after testosterone replacement therapy (TRT) on all-cause mortality, myocardial infarction (MI), and stroke in male smokers and nonsmokers without history of MI and stroke.
Participants and methods: Data from 18,055 males with known CS status and low TT levels who received TRT at the Veterans Health Administration between December 1, 1999, and May 31, 2014, were grouped into (1) current smokers with normalized TT, (2) current smokers with nonnormalized TT, (3) nonsmokers with normalized TT, and (4) nonsmokers with nonnormalized TT. Combined effect of CS status and TT level normalization after TRT on all-cause mortality, MI, and stroke was compared using propensity score-weighted Cox proportional hazard models.
Results: Normalization of serum TT levels in nonsmokers was associated with a significant decrease in all-cause mortality (hazard ratio [HR]=0.526; 95% CI, 0.477-0.581; P<.001) and MI (HR=0.717; 95% CI, 0.522-0.986; P<.001). Among current smokers, normalization of serum TT levels was associated with a significant decrease in only all-cause mortality (HR=0.563; 95% CI, 0.488-0.649; P<.001) without benefit in MI (HR=1.096; 95% CI, 0.698-1.720; P=.69). Importantly, compared with nonsmokers with normalized TT, all-cause mortality (HR=1.242; 95% CI, 1.104-1.396; P<.001), MI (HR=1.706; 95% CI, 1.242-2.342; P=.001), and stroke (HR=1.590; 95% CI, 1.013-2.495; P=.04) were significantly higher in current smokers with normalized TT.
Conclusion: We conclude that active CS may negate the protective effect of testosterone level normalization on all-cause mortality and MI after TRT.
Keywords: BMI, body mass index; CAD, coronary artery disease; CDW, Corporate Data Warehouse; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; CS, current smoking; CV, cardiovascular; CVD, cardiovascular disease; DM, diabetes mellitus; HR, hazard ratio; ICD-9, International Classification of Diseases, Ninth Revision; IPTW, inverse probability of treatment weights; LDL, low-density lipoprotein; MI, myocardial infarction; OSA, obstructive sleep apnea; PVD, peripheral vascular disease; TRT, testosterone replacement therapy; TT, total testosterone; VA, Veterans Administration; VHA, Veterans Health Administration.