Associations of total testosterone, sex hormone-binding globulin, calculated free testosterone, and luteinizing hormone with prevalence of abdominal aortic aneurysm in older men.

CONTEXT

Abdominal aortic aneurysm (AAA) is associated with mortality in older adults, and increasing aortic diameter predicts incident cardiovascular events. Although AAA occurs predominantly in men, its association with male sex hormones is unclear.

OBJECTIVE

The objective of the study was to examine whether male sex hormones are independently associated with AAA or increased abdominal aortic diameter.

DESIGN

This was a cross-sectional analysis.

SETTING AND PARTICIPANTS

Participants included 3620 community-dwelling men aged 70-88 yr.

MAIN OUTCOME MEASURES

Abdominal aortic diameter was measured with ultrasound. Early morning sera were assayed for total testosterone, SHBG, and LH. Free testosterone was calculated using mass action equations.

RESULTS

AAA (aortic diameter > or =30 mm) was present in 262 men (7.2%). Men with AAA had lower serum total and free testosterone (mean +/- sd 14.5 +/- 6.0 vs. 15.5 +/- 5.6 nmol/liter, P = 0.005 and 256 +/- 87 vs. 280 +/- 97 pmol/liter, P < 0.001, respectively) compared with men without. LH was higher in men with AAA (median, interquartile range: 4.9, 3.1-7.9 vs. 4.3, 3.0-6.4 IU/liter, P = 0.013). In multivariate analysis adjusting for potential confounders, free testosterone was negatively associated with AAA (odds ratio per 1 sd increase: 0.84, 95% confidence interval 0.72-0.98, P = 0.026). LH was positively associated (odds ratio 1.14, 95% confidence interval 1.03-1.25, P = 0.008). Comparable results were seen with aortic diameter analyzed as a continuous variable.

CONCLUSIONS

Lower free testosterone and higher LH levels are independently associated with AAA in older men. Impaired gonadal function may be involved in arterial dilatation as well as occlusive vascular disease in older men. Additional studies are needed to clarify direction of causality and determine possible scope for preventive intervention.