Older men with higher circulating androgen levels combined with higher levels of physical activity are less likely to develop metabolic syndrome or die of cardiovascular disease than men with lower androgen levels combined with low physical activity, according to a cross-sectional analysis published in Clinical Endocrinology.
“In older men, having higher testosterone concentrations and being more physically active may reflect being healthier, or may contribute to better health,” Bu Beng Yeap, MBBS, FRACP, PhD, a professor at the University of Western Australia Medical School and endocrinologist at Fiona Stanley Hospital in Perth, Western Australia, told Endocrine Today.
Yeap and colleagues analyzed data from 3,351 older men participating in the population-based Health in Men Study who completed questionnaires assessing physical activity and attended physical exams between 1996 and 1999 and again between 2001 and 2004 (mean age, 77 years; mean BMI, 26.4 kg/m²). Metabolic syndrome was defined as meeting at least three of five criteria: hypertension, hyperglycemia, hypertriglyceridemia, low HDL cholesterol or central obesity. Follow-up of hospital admissions and death were assessed via the Western Australia Data Linkage System.
Based on using median splits to determine “high” vs. “low,” researchers stratified the cohort by four groups: high hormone and high physical activity; high hormone and low physical activity; low hormone and high physical activity; and low hormone and low physical activity.
Researchers used linear regression to compare mean BMI and waist circumference across the four groups and logistic regression to compare the prevalence of metabolic syndrome across groups. In follow-up analysis, researchers used Cox proportional hazard models to compare risk for fatal and nonfatal CV events across the four groups.
During a mean follow-up period of 10 years, researchers observed 865 CVD events and 499 CV deaths.
Researchers found that, in models adjusted for age, prevalent CVD, smoking and cardiometabolic factors, men with higher total testosterone and higher levels of physical activity had a lower risk for CV events during follow-up than men with low testosterone and low physical activity (HR = 0.81; 95% CI, 0.67-0.98), as did men with higher testosterone but low levels of physical activity (HR = 0.73; 95% CI, 0.6-0.89).
“Thus, higher [testosterone] was associated with lower incidence of CVD events irrespective of [physical activity] levels,” the researchers wrote.
In similarly adjusted models, men with higher levels of testosterone or dihydrotestosterone and higher physical activity were less likely to die of CV causes during follow-up vs. men with low levels of testosterone or dihydrotestosterone, with HRs of 0.76 (95% CI, 0.59-0.98) in the testosterone group and 0.71 (95% CI, 0.55-0.92) for the dihydrotestosterone group.
Researchers also observed an inverse association between higher androgens and higher physical activity with a lower, age-adjusted risk for metabolic syndrome, with men in the high hormone, high physical activity group seeing the greatest benefit. Results for calculated free testosterone mirrored findings observed with total testosterone, according to the researchers.
Yeap said the findings provide a rationale for further research.
“A randomized controlled trial in which men are treated with testosterone and provided with an exercise program would be needed to prove whether or not this would improve their health,” Yeap said.
For more information:
Bu Beng Yeap, MBBS, FRACP, PhD, can be reached at the Harry Perkins Institute of Medical Research, 11 Robin Warren Drive, Murdoch 6150, Western Australia, Australia; email: bu.yeap@uwa.edu.au.