An age-related increase in estrogen may be the culprit behind inguinal hernia, a condition common among elderly men that often requires corrective surgery, suggests new study.

One consequence of ageing in men is that a larger share of the male sex hormone testosterone is converted to estrogen by a hormone called aromatase. In the study, the researchers found the lower abdominal muscles of mice are particularly sensitive to estrogen, developing scar tissue in response to increases in estrogen levels that weaken the abdominal wall and eventually cause a hernia.

When the investigators reduced estrogen with a drug compound, it prevented the hernia, suggesting a therapy with preventive potential in humans, said the study published in the journal Proceedings of the National Academy of Sciences. "It may make sense to treat at-risk men with an aromatase inhibitor that could decrease estrogen and strengthen the muscle," said lead researcher Serdar Bulun, Professor at Northwestern University Feinberg School of Medicine in Chicago, US.

Inguinal hernia occurs when tissue, such as the intestines, protrudes through the inguinal canal, a weak spot near the groin in the human abdominal wall. This hernia is the most common reason men undergo surgery. While the chances of an inguinal hernia increases as men age, the root cause remains unknown.

When the investigators gave the mice a drug that blocked aromatase, and therefore the conversion of testosterone to estrogen, the hernias stopped, pointing toward estrogen as the cause and indicating potential for an aromatase inhibitor therapy that may be able to prevent surgery in at-risk patients, Bulun said.