Framingham Heart Study: Serum testosterone linked to vascular calcification
HOUSTON — Low circulating testosterone levels in men are associated with increased vascular calcification that is not otherwise explained by age, new data suggest. However, researchers said this could be due to their co-occurrence with established cardiovascular risk factors.
Thomas G. Travison, PhD, associate professor in the department of biostatistics at the School of Public Health at Boston University School of Medicine, and colleagues used data on 1,678 patients from Generation 2 and Generation 3 of the Framingham Heart Study cohort to analyze the link between serum testosterone and vascular calcification in adult men. Data were collected in clinical study from 1998 to 2008.
Patients were aged 31 to 80 years, with a mean BMI of 28. Average total testosterone was 616 ng/dL, free testosterone was 111 pg/mL and sex hormone-binding globulin (SHBG) was 46 nmol/L.
Researchers measured early-morning serum total testosterone by liquid chromatography-tandem mass spectrometry, and free testosterone was calculated using mass action equations. They measured SHBG using immunofluorometric assay. CT scan was used to measure thoracic aortic calcification, abdominal aortic calcification and coronary artery calcification.
Covariables included age, BMI, smoking, fasting lipids and comorbid conditions. Travison said they found that total testosterone and free testosterone displayed positive associations, whereas SHBG exhibited a negative association, with vascular calcification (P<.001).
Data indicated no relationship between SHBG and vascular calcification. When scaled to the average sample coronary artery calcification, researchers found that a 100-ng/dL between-subject increase in total testosterone was associated with an average age-adjusted decrease in coronary artery calcium of –8.6% (4.5%; P=.04).
Similarly, a 10 pg/mL positive difference in free testosterone was associated with a mean decrease in coronary artery calcium of –5.1% (2.5%; P=0.04). Trends of similar magnitude were observed for abdominal aortic calcification and thoracic aortic calcification.
“Total and free testosterone split a negative association with coronary and aortic calcification, risk factors and markers for atherosclerosis,” Travison said.
For more information:
Travison TG. Abstract #OR28-1. Presented at: the Endocrine Society’s 94th Annual Meeting & Expo; June 23-26, 2012; Houston.
Disclosure: The researchers report no relevant financial disclosures.