Insight on pathogenesis of varicoceles: relationship of varicocele and body mass index

Varicoceles, present in 15% to 20% of men, are the most common abnormal finding among men presenting with infertility, yet controversy exists regarding their etiology. Anecdotal experience suggests that varicoceles are more prevalent in lean men, supporting the "nutcracker" effect of the superior mesenteric artery compressing the left renal vein over the aorta. We examined this hypothesis in a large adult population.

A total of 2106 men were evaluated for infertility or erectile dysfunction from 1990 to 1996. The men were examined for the presence and severity of a varicocele. The association between age, height, body mass index, year of evaluation, and reason for consultation and the presence and severity of a varicocele was examined using logistic regression analysis.

The mean age was 47 years (range 18 to 85), and the median body mass index was 26.4 kg/m2 (range 15.4 to 53.3). A varicocele was present in 398 men (18.9%). Stratified by grade, 59 (14.8%) were grade III, 155 (38.9%) were grade II, and 184 (46.2%) were grade I. The prevalence of varicoceles in the erectile dysfunction group (12.7%) was significantly less (P <0.001) than in the infertile group (32.2%). Multivariate logistic regression analysis revealed a statistically significant inverse relationship between body mass index and the presence of a varicocele.

Varicoceles were less likely to be diagnosed among obese men. Although this suggests that the "nutcracker" phenomenon or other biophysical effects of increased adiposity may play a role in the pathogenesis, other factors could not be excluded as contributing to our findings.