Men with low testosterone levels may have an increased mortality rate, according to a study published in the journal Heart.

Over the course of approximately seven years, researchers monitored the health of 930 men who had been diagnosed with coronary artery heart disease. The team then took tissue samples from the participants, which allowed them to measure bioavailable testosterone (bio-T) or total testosterone (TT). As a result, one in four of the individuals were found to have low testosterone levels.

Throughout the trial, approximately 42 percent or 1 out of every 5 participants who had low levels of testosterone died. However, among those with normal hormone levels, an estimated 12 percent or 1 out of every 8 men had passed away.

While patients with irregular testosterone levels may benefit from hormone replacement therapies, the investigators determined that further research will be needed to prove if cardiovascular problems could affect the effectiveness of these treatments.

In addition to heart problems, low testosterone levels can lead to an increased risk of Alzheimer’s disease in men, according to a study conducted at Saint Louis University.