High levels of occupational exposure to pesticides may be associated with increased risk for cardiovascular disease (CVD), according to study results published in Journal of the American Heart Association.

Previous studies have shown that pesticides are associated with CVD, especially in subjects wearing little or no proper personal protective equipment. However, most of the studies have focused on CVD mortality. The goal of the current study was to explore the association between occupational exposure to pesticides and the incidence of CVD, coronary heart disease (CHD), and cerebrovascular accident (CVA).

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Findings come from data collected by the Kuakini Honolulu Heart Program, established in 1965 to study CVD in a cohort of middle-aged Japanese-American men living on the island of Oahu, Hawaii. In addition to undergoing multiple examinations, researchers tracked all causes of death and some disease outcomes among participants. Data on rates of CHD and CVA were available through December 1999, for up to 34 years of follow-up.

All preexisting cases of CVD (CHD or CVA) at baseline were excluded, leaving a sample of 7557 participants. Pesticide exposure was assessed using a scale from the Occupational Safety Health Administration that assesses the intensity and length of occupational exposure of each job.

Compared to men who were not exposed to pesticides at work, in the first 10 years of follow-up there was a positive association between CVD incidence and high levels of pesticides exposure following adjustment for age (hazard ratio=1.46; 95% CI, 1.10-1.95; P =.009) and for other CVD risk factors (hazard ratio=1.42; 95% CI, 1.05-1.92; P =.021).

Separate analysis for outcomes of incident CHD and CVA showed no significant association, which researchers attributed to the smaller number of outcomes with inadequate power to detect differences. The maximum effect of exposure to pesticides was seen within 10 years of exposure, with no association in follow-up periods >10 years and up to 34 years after exposure.

“After following the men for 34 years, the link between being exposed to pesticides at work and heart disease and stroke was no longer significant,” said Beatriz L Rodriguez, MD, PhD, MPH, co-author of the study and professor of geriatric medicine at the University of Hawaii at Manoa. She added, “this was probably because other factors tied to aging became more important, masking the possible relation of pesticides and cardiovascular disease later in life.”

Factors that may have limited findings of this study included a lack of information regarding the specific pesticides to which each participant was exposed, that the study population was limited to men of Japanese ancestry, the relatively small sample size of patients with a moderate intensity of exposure to pesticides, and the inability to adjust for all possible CVD risk factors.

The researchers concluded that these findings provide insight into the adverse effects of pesticides on the cardiovascular system and confirm a positive association between high levels of pesticide exposure and CVD incidence. Dr Rodriguez also noted that the study “emphasizes the importance of using personal protective equipment during exposure to pesticides on the job and the importance of documenting occupational exposure to pesticides in medical records, as well as controlling standard heart disease risk factors.”

Reference

Berg ZK, Rodriguez B, Davis J, Katz AR, Cooney RV, Masaki K. Association between occupational exposure to pesticides and cardiovascular disease incidence: the Kuakini Honolulu Heart Program (published online September 25, 2019). J Am Heart Assoc. doi:10.1161/JAHA.119.012569