FRIDAY, Oct. 27 (HealthDay News) -- The testosterone-fueled American male may be losing his punch.They controlled for smoking and obesity, but should should have controlled for having feminist wives and voting for John Kerry.
Over the past two decades, levels of the sex hormone in U.S. men have been falling steadily, a new study finds.
For example, average total testosterone levels in men aged 65 to 69 fell from 503 nanograms/decileter (ng/dL) in 1988 to 423 ng/dL in 2003.
The reasons for this trend are unclear, said researchers at the New England Research Institutes in Waterdown, Mass. They noted that neither aging nor certain other health factors, such as smoking or obesity, can fully explain the decline. ...
"In 1988, men who were 50 years and older had higher serum testosterone concentrations than did comparable 50-year-old men in 1996. This suggests that some factor other than age may be contributing to the observed declines in testosterone over time," Travison said.
He and his colleagues analyzed blood samples -- along with health and other information -- from about 1,500 men in the greater Boston area who took part in the Massachusetts Male Aging Study. That study collected data in 1987-89, 1995-97, and 2002-04. ...
The findings were published in the Journal of Clinical Endocrinology and Metabolism.
Barbara blames pesticides:
(Beyond Pesticides, January 19, 2006) A study published in the January issue of Epidemiology has found inverse associations between pesticides and male testosterone levels. The study, conducted by researchers at University of Michigan, Harvard University, and the Centers for Disease Control and Prevention in Atlanta, has found that high levels of the urinary metabolites of chlorpyrifos (TCPY) and carbaryl and naphthalene (1N) correlate directly with low levels of testosterone in male subjects.