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Low testosterone in men raises risk for atherosclerosis
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Lower levels of total and free testosterone in men are associated with a higher risk for coronary atherosclerosis, but a lower risk for carotid intima-media thickness, according to research in Clinical Endocrinology.
Bahram Khazai, MD, of the Los Angeles Biomedical Research Institute and UCLA School of Medicine in Torrance, California, and colleagues analyzed baseline endogenous sex hormone levels from 3,164 men without a known history of cardiovascular disease (mean age, 62 years) participating in the Multi-Ethnic Study of Atherosclerosis (MESA), a prospective cohort study of subclinical CVD between 2000 and 2002. Blood samples were drawn from participants after a 10- to 12-hour fast between 7:30 a.m. and 10:30 a.m.; researchers measured levels of total testosterone, free testosterone and bioavailable testosterone, as well as estradiol, sex hormone-binding globulin and albumin concentrations. Participants underwent CT scans to measure coronary artery calcium and B-mode ultrasound to measure carotid intima-media thickness.
Researchers examined the cross-sectional associations of tertiles of endogenous sex hormones with both coronary artery calcium and carotid intima-media thickness, using the lowest limit for diagnosis of hypogonadism in the European Male Aging Study for serum total testosterone (8 nmol/L), the lower limit of the generally accepted reference range for serum total testosterone in adult males (10.4 nmol/L), the level commonly used to determine testosterone replacement (9.54 nmol/L) or no treatment (12.1 nmol/L) as cutoff points. Results were adjusted for age and CVD risk factors.
Researchers found free testosterone was negatively associated with the presence of coronary artery calcium, with a significant trend over tertiles of free testosterone for coronary artery calcium (P = .02). Researchers also found a marginally significant positive trend over tertiles for SHBG (P = .08) for coronary artery calcium.
Researchers also found significantly higher log coronary artery calcium in men with lower total testosterone levels vs. higher levels when using 9.54 nmol/L and 10.4 nmol/L as cutoff points, but not for 8 nmol/L or 12.1 nmol/L cutoff points.
There was a positive trend in mean carotid intima-media thickness over bioavailable testosterone tertiles (P = .003), but not for other sex hormones. After adjustment for CVD risk factors, there was lower carotid intima-media thickness for those with lower total testosterone levels vs. those with high levels.
“Because the prevalence of [coronary artery calcium] corresponds to the prevalence of CVD, our findings regarding the [coronary artery calcium] when using several [total testosterone] cutoff points suggest that [total testosterone] above 9.54 nmol/L to 10.4 nmol/L may be correlated with lower prevalence of CVD in men,” the researchers wrote. “The fact that we found a positive association between [bioavailable testosterone] and [carotid intima-media thickness] may suggest that correlation of endogenous sex hormones with atherosclerosis might be different in carotid arteries compared to coronary arteries.” – by Regina Schaffer
Disclosure: Endocrine Today was unable to determine relevant financial disclosures.
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