Endogenous testosterone and mortality in men: A systematic review and meta-analysis

Abstract

Context: Low testosterone levels have been associated with outcomes that reduce survival in men. Objective: Our objective was to perform a systematic review and meta-analysis of published studies to evaluate the association between endogenous testosterone and mortality. Data Sources: Data sources included MEDLINE (1966 to December 2010), EMBASE (1988 to December 2010), and reference lists. Study Selection: Eligible studies were published English-language observational studies of men that reported the association between endogenous testosterone and all-cause or cardiovascular disease (CVD) mortality. A two-stage process was used for study selection. 1) Working independently and in duplicate, reviewers screened a subset (10%) of abstracts. Results indicated 96% agreement, and thereafter, abstract screening was conducted in singlicate. 2) All full-text publications were reviewed independently and in duplicate for eligibility. Data Extraction: Reviewers working independently and in duplicate determined methodological quality of studies and extracted descriptive, quality, and outcome data. Data Synthesis: Of 820 studies identified, 21 were included in the systematic review, and 12 were eligible for meta-analysis [n = 11 studies of all-cause mortality (16,184 subjects); n = 7 studies of CVD mortality (11,831 subjects)]. Subject mean age and testosterone level were 61 yr and 487 ng/dl, respectively, and mean follow-up time was 9.7 yr. Between-study heterogeneity was observed among studies of all-cause (P