Low testosterone linked with metabolic syndrome in middle-aged Japanese
MedWire News: Low testosterone levels are associated with the metabolic syndrome (MetS) in middle-aged Japanese men, a study has shown.
The findings, published in the journal Hypertension Research, join those from earlier studies showing an association between MetS and low testosterone levels in Caucasians.
Low testosterone was positively related to MetS, MetS components, and additional metabolic risk factors.
The researchers say: “Our results reinforce the need to address the causal relationship and pathophysiological interactions between sex hormones and MetS.”
Masahiro Akishita (University of Tokyo, Japan) and colleagues conducted their study after previously finding evidence linking testosterone and cardiovascular pathology.
To investigate further, they studied 194 men aged 30 to 64 years, from whom blood samples were taken in the morning after a 12-hour fast.
MetS was diagnosed in 23% of the men according to the Japanese criteria and in 32% using the International Diabetes Federation definition for MetS in people of Japanese ethnicity.
Both definitions of MetS showed an association with low testosterone levels, with corresponding hazard ratios of 2.02 and 1.68 by quartile decline in the sex hormone.
Age-adjusted regression analysis showed that testosterone was significantly related to obesity (a parameter of MetS), including waist circumference and body mass index.
The same was true for hypertension, both systolic and diastolic blood pressure, and dyslipidemia, including triglycerides and high-density lipoprotein cholesterol, as well as insulin resistance and adiponectin.
Including waist circumference in the model weakened the association of testosterone with other metabolic risk factors.
In contrast, high estradiol was associated with MetS and its parameters, which was mostly attributable to a positive correlation between estradiol and obesity.
“Dehydroepiandrosterone sulfate was not associated with MetS or its parameters,” note the researchers.
They add: “Taken together, results in this statistical model suggest that abdominal obesity is an important contributor to the association between low testosterone and MetS, but additional factors may also impact testosterone.”
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By Anita Wilkinson