Veterans Health Administration

Study of nearly 4,000 Veterans in the Army Chemical Corps between 1965 and 1973

VA researchers found a link between service-related occupational exposure to herbicides and high blood pressure (hypertension) risk among U.S. Army Chemical Corps (ACC) Veterans, a group of Veterans assigned to do chemical operations during the Vietnam War. Researchers also found an association between military service in Vietnam and hypertension risk among these Veterans.

Researchers at VA’s Post Deployment Health Services Epidemiology Program, Office of Patient Care Services, conducted the Army Chemical Corps Vietnam-Era Veterans Health Study, a three-phase study of nearly 4,000 Veterans who served in the U.S. Army Chemical Corps between 1965 and 1973. The study included a survey that requested information on these Veterans’ exposure to herbicides, whether they were ever diagnosed with hypertension by a physician, and their health behaviors such as cigarette smoking and alcohol use. To confirm self-reported hypertension, researchers conducted in-home blood pressure measurements and a medical records review for a portion of study participants.  

Hypertension highest among Veterans who distributed or maintained herbicides (sprayers) in Vietnam.

ACC Veterans were studied because of their documented occupational involvement with chemical distribution, storage, and maintenance while in military service.This study follows a request by former Secretary of Veterans Affairs Eric K. Shinseki for VA to conduct research on the association between herbicide exposure and hypertension to learn more about if hypertension is related to military service in Vietnam. The research was originally designed and led by Han Kang, Dr.P.H., former director of VA’s Epidemiology Program (now retired). Yasmin Cypel, Ph.D., M.S., another researcher with VA’s Epidemiology Program, is currently the principal investigator on this study, which extends prior research on these Veterans.

“This study expands our knowledge of the relationship between hypertension risk and both herbicide exposure and service in Vietnam among Veterans who served during the War by focusing on a specific group of Vietnam era Veterans who were occupationally involved in chemical operations,” said Dr. Cypel.     

Self-reported hypertension was the highest among Veterans who distributed or maintained herbicides (sprayers) in Vietnam (81.6%), followed by Veterans who sprayed herbicides and served during the Vietnam War but never in Southeast Asia (non-Vietnam Veterans) (77.4%), Veterans who served in Vietnam but did not spray herbicides (72.2%), and Veterans who did not spray herbicides and were non-Vietnam Veterans (64.6%).

The odds of hypertension among herbicide sprayers were estimated to be 1.74 times the odds among non-sprayers, whereas the odds of hypertension among those who served in Vietnam was 1.26 times the odds among non-Vietnam Veterans.

The researchers would like to extend their thanks to all those Army Chemical Corps Vietnam Era Veterans who participated in this study for their contribution to the research.  Without their input there would be no findings to report and no additions to existing findings on the health consequences of military service during the Vietnam War. 

VA will review the results from this research, along with findings from other similar studies and recommendations from the recent National Academies of Science report on Veterans and Agent Orange, when considering whether to add hypertension as a presumptive service condition for Vietnam Veterans.

To read more about the Army Chemical Corps Vietnam-Era Veterans Health Study, go to http://www.publichealth.va.gov/epidemiology/studies/vietnam-army-chemical-corps.asp.  To read the published article containing findings from this study, go to https://www.ncbi.nlm.nih.gov/pubmed/27820763.