Study Links Antibiotic Use to Development of CVD in Women

Long-term antibiotic use in women 40 and older could lead to an increased risk of developing cardiovascular disease (CVD), according to a new study.

After examining more than 35,000 women, investigators found taking antibiotics for 2 months or more later in life could result in a 32% in likelihood of developing a CVD.

In response to data that suggests antibiotic exposure is associated with a long-lasting alteration in gut microbiota and may be related to subsequent cardiovascular disease, investigators sought to investigate the associations of life-stage and duration of antibiotic exposure during adulthood with subsequent CVD events.

Investigators obtained data through the Nurses’ Health Study, which is an ongoing cohort study established in 1976 of more than 100,000 female registered nurses in the US. Investigators chose 2004 as the baseline year and a total of 90,853 women returned the 2004 questionnaire.

Investigators excluded 33,147 women for missing data on antibiotic usage, 17,659 were excluded due to prior history of CVD, 2469 were excluded because there was no available data on demographic factors, 747 women were excluded because they only returned the 2004 questionnaire, and 422 were excluded because they were under the age of 60. A total of 36,429 women were included in the study. Respondents filled out a questionnaire every 2 years that asked about use of antibiotics during their young (20-39), middle-age (40-59), and later (60 and older) stages of life.

Investigators examined data from 2004 to June 2012 and categorized participants into 4 groups: those who had never taken antibiotics, those who had taken them for time periods of less than 15 days, 15 days to two months, or for two months or longer. A total of 1056 participants developed CVD during the study.

After analyses, investigators determined that women who consumed antibiotics for 2 months or longer in middle age or later life had an increased risk of developing CVD than those who did not use antibiotics. Women who took them in later life were 32% more likely to develop CVD and women who took them in middle age had a 28% increased risk. Investigators noted that while they found a link between CVD and antibiotic use in middle-age and later life, they found no increased risk from antibiotic use in young adults.

The findings suggest that among women who take antibiotics for 2 months or more late adulthood, six women per 1,000 would develop a cardiovascular disease, compared to three per 1,000 among women who had not taken antibiotics.

“By investigating the duration of antibiotic use in various stages of adulthood we have found an association between long-term use in middle age and later life and an increased risk of stroke and heart disease during the following eight years,” said Yoriko Heianza, RD, PhD, study author and research fellow at Tulane University. “As these women grew older they were more likely to need more antibiotics, and sometimes for longer periods of time, which suggests a cumulative effect may be the reason for the stronger link in older age between antibiotic use and cardiovascular disease.”

The authors noted several limitations within their study. As they were using self-reported information, use of antibiotics could be misremembered. Investigators lacked information on what type of antibiotics were used. Additionally, the study only examined women and the results cannot be extrapolated to younger ages and men.

This study, titled “Duration and life-stage of antibiotic use and risk of cardiovascular events in women,” was published in the European Heart Journal.