Women 60 and older who take antibiotics for more than a couple of months have a higher risk of all-cause and cardiovascular death, according to research presented March 22 at the American Heart Association’s Epidemiology and Prevention/Lifestyle and Cardiometabolic Health scientific sessions.

“Gut microbiota alterations have been associated with a variety of life-threatening disorders, such as cardiovascular diseases and certain types of cancer,” study author Lu Qi, MD, PhD, a professor of epidemiology at Tulane University, said in a press release. “Antibiotic exposure affects balance and composition of the gut microbiome even after one stops taking antibiotics. So, it is important to better understand how taking antibiotics might impact risks for chronic diseases and death.”

Qi and colleagues studied 37,510 women who were at least 60 years old and free of cancer and heart disease when they enrolled in the trial. Over an eight-year follow-up, women who took antibiotics for at least two months demonstrated a 58 percent greater risk of cardiovascular death and a 27 percent greater chance of dying from any cause than women who didn’t take antibiotics at all.

In addition, women who also reported using antibiotics in middle-age (40 to 59 years old) had a higher risk of all-cause death than those who didn’t use antibiotics during that timeframe.

However, it remains unclear whether taking the medications had a causal effect on mortality or if those individuals were just sicker in general, Qi said.

 “These results … contribute to a better understanding of risk factors for all-cause and cardiovascular death,” he said. “We now have good evidence that people who take antibiotics for long periods during adulthood may be a high-risk group to target for risk-factor modification to prevent heart disease and death.”