In the Journals

Higher testosterone associated with insulin resistance, metabolic syndrome, CVD in women

Women aged 65 years or older with high testosterone levels were more likely to have insulin resistance, metabolic syndrome and cardiovascular disease than women with normal levels of the hormone.

Researchers evaluated 344 women aged 65 to 98 enrolled in the Cardiovascular Health Study. Researchers then performed cross-sectional analyses to investigate the associations between total and free testosterone, and insulin resistance, metabolic syndrome and CVD.

Mean total testosterone levels were 19.1 ng/dL and mean free testosterone levels were 2.8 pg/mL. Mean BMI was 26.9.

The researchers reported a stepwise increase in insulin resistance associated with increasing levels of total (P=.003) and free testosterone (P=.02). There was a similar stepwise decrease in insulin sensitivity as total (P≤.001) and free testosterone (P=.002) increased.

They observed a strong relationship between total testosterone levels and metabolic syndrome in both crude (P<.001) and adjusted models (P=.007) when examining the prevalence of metabolic syndrome by quartile of total testosterone level. The odds for metabolic syndrome for women in the top quartile of total testosterone levels was three times greater than the odds for those in the bottom quartile (OR=3.15; 95% CI, 1.57–6.35). That effect held even when researchers adjusted for BMI (OR=2.81; 95% CI, 1.32–5.98).

The association between total testosterone levels and metabolic syndrome persisted even when researchers excluded women with diabetes. Women in the highest quartile for total testosterone levels still had a threefold greater chance metabolic syndrome compared with women in the lowest quartile (OR=2.89; 95% CI 1.36–6.16).

Similarly, women in the top quartile for total testosterone levels had threefold greater odds for CVD compared with women in the reference quartile (OR=2.95; 95% CI, 1.2–7.3). The association was independent of sociodemographic and traditional CV risk factors.

Free testosterone levels were also associated with high fasting glucose (OR=2.37; 95% CI, 1.17–4.79) and abdominal obesity (OR 2.23; 95% CI, 1.08–4.61).

“Our findings suggest that even at the physiologically low levels of testosterone found in these older women, the association between testosterone and insulin resistance found in perimenopausal and early postmenopausal women persists into old age,” the researchers wrote. “Further studies are required to determine whether a causal relationship exists between testosterone and insulin resistance and to provide more insight into the role testosterone plays in the pathogenesis of CVD in women.”

Patel SM. J Clin Endocrinol Metab. 2009;doi:10.1210/jc.2009-0740.

PERSPECTIVE

These data are not surprising. Higher testosterone levels have been associated with higher CV risk in men so why not women?

- George Bakris, MD
Endocrine Today Editorial Board member

Women aged 65 years or older with high testosterone levels were more likely to have insulin resistance, metabolic syndrome and cardiovascular disease than women with normal levels of the hormone.

Researchers evaluated 344 women aged 65 to 98 enrolled in the Cardiovascular Health Study. Researchers then performed cross-sectional analyses to investigate the associations between total and free testosterone, and insulin resistance, metabolic syndrome and CVD.

Mean total testosterone levels were 19.1 ng/dL and mean free testosterone levels were 2.8 pg/mL. Mean BMI was 26.9.

The researchers reported a stepwise increase in insulin resistance associated with increasing levels of total (P=.003) and free testosterone (P=.02). There was a similar stepwise decrease in insulin sensitivity as total (P≤.001) and free testosterone (P=.002) increased.

They observed a strong relationship between total testosterone levels and metabolic syndrome in both crude (P<.001) and adjusted models (P=.007) when examining the prevalence of metabolic syndrome by quartile of total testosterone level. The odds for metabolic syndrome for women in the top quartile of total testosterone levels was three times greater than the odds for those in the bottom quartile (OR=3.15; 95% CI, 1.57–6.35). That effect held even when researchers adjusted for BMI (OR=2.81; 95% CI, 1.32–5.98).

The association between total testosterone levels and metabolic syndrome persisted even when researchers excluded women with diabetes. Women in the highest quartile for total testosterone levels still had a threefold greater chance metabolic syndrome compared with women in the lowest quartile (OR=2.89; 95% CI 1.36–6.16).

Similarly, women in the top quartile for total testosterone levels had threefold greater odds for CVD compared with women in the reference quartile (OR=2.95; 95% CI, 1.2–7.3). The association was independent of sociodemographic and traditional CV risk factors.

Free testosterone levels were also associated with high fasting glucose (OR=2.37; 95% CI, 1.17–4.79) and abdominal obesity (OR 2.23; 95% CI, 1.08–4.61).

“Our findings suggest that even at the physiologically low levels of testosterone found in these older women, the association between testosterone and insulin resistance found in perimenopausal and early postmenopausal women persists into old age,” the researchers wrote. “Further studies are required to determine whether a causal relationship exists between testosterone and insulin resistance and to provide more insight into the role testosterone plays in the pathogenesis of CVD in women.”

Patel SM. J Clin Endocrinol Metab. 2009;doi:10.1210/jc.2009-0740.

PERSPECTIVE

These data are not surprising. Higher testosterone levels have been associated with higher CV risk in men so why not women?

- George Bakris, MD
Endocrine Today Editorial Board member