University Park, Pa. -- Higher levels of testosterone can have significant health benefits for some middle-aged men, according to a Penn State study.
"Men with higher testosterone are less vulnerable to high blood pressure, heart attacks, frequent colds and obesity," says Dr. Alan Booth, professor of sociology and human development. "In addition, they are more likely to rate their health as excellent or good rather than fair or poor. Studies show self ratings of health correlate highly with physicians' assessments.
"The benefits of higher testosterone levels have a down side, however," Booth notes. "Some, but not all, men with higher levels of testosterone are more likely to engage in behavior that cancels out the beneficial effects of testosterone."
Those with higher levels of testosterone are more inclined to smoke, drink alcohol excessively and indulge in risky behavior that leads to injury. The biggest detriment to health by far is the tendency for high testosterone men to smoke.
Booth; Dr. Douglas A. Granger, assistant professor of biobehavioral health and director of Penn State's Behavioral Endocrinology Laboratory in the College of Health and Human Development; and Dr. David R. Johnson, professor of sociology at the University of Nebraska-Lincoln, have published their work in the paper, "Testosterone and Men's Health, in a recent issue of the Journal Of Behavioral Medicine.
The researchers studied testosterone and health in a sample of 4,393 men between the ages of 32 and 44 who had served in the military between 1965 and 1971. The men were interviewed and medically examined. Testosterone was measured in plasma from blood drawn at 8 a.m. Concentrations ranged from 53 nanograms per deciliter (ng/dl) to 1,500 with an average of 679.
"Comparison of men with slightly average levels of testosterone (400/ng/dl) with men with slightly above average levels (800 ng/dl) revealed significant differences in the indicators of health," Booth says.
Men at the higher level were 45 percent less likely to have high blood pressure, 72 percent less likely to have experienced a heart attack, 8 percent less likely to have 3 or more colds in a year, and 45 percent less likely to rate their health as fair or poor.
On the negative side, men at the higher level were 25 percent more likely to report one or more injuries, 32 percent more likely to imbibe 5 or more drinks in a single day and 151 percent more likely to smoke.
"We don't yet fully understand how testosterone benefits health or leads to behaviors detrimental to health," Booth says. "More studies are needed to discover the missing pieces to this puzzle. What is clear is that men with higher testosterone levels are at higher risk for negative health outcomes. But there are many men with higher testosterone who don't engage in health risk behavior and who do realize testosterone-related health benefits."
Increasing men's awareness of their testosterone levels may be worthwhile in terms of health promotion and disease prevention efforts, say the researchers. Regular monitoring of testosterone levels would make it easier to optimize the sensitive balance between testosterone's positive and negative effects, especially if it is done as part of overall physical checkups.
"Monitoring testosterone through saliva samples is now possible and offers distinct advantages over the traditional means of assaying blood," Granger notes. "Saliva sampling is non-invasive, samples can be self-collected, repeated samples can be obtained with minimal effort and the accuracy of saliva assays has substantially improved in recent years."