Psychological traits such as optimism and hostility affect coronary heart disease (CHD) risk, but mechanisms for this association are unclear. We hypothesized that optimism and hostility may affect CHD risk via changes in heart rate variability (HRV).
We conducted a longitudinal analysis using data from the Women's Health Initiative Myocardial Ischemia and Migraine Study. Participants underwent 24-hour ambulatory electrocardiogram monitoring 3 years after enrollment. Optimism (Life Orientation Test-Revised), cynical hostility (Cook-Medley), demographics, and coronary risk factors were assessed at baseline. HRV measures included standard deviation of average N-N intervals (SDNN); standard deviation of average N-N intervals for 5 minutes (SDANN); and average heart rate (HR). CHD was defined as the first occurrence of myocardial infarction, angina, coronary angioplasty, and bypass grafting. Linear and Cox regression models adjusted for CHD risk factors were used to examine, respectively, associations between optimism, hostility, and HRV and between HRV and CHD risk.
Final analyses included 2655 women. Although optimism was not associated with HRV, hostility was inversely associated with HRV 3 years later (SDANN: adjusted β = −0.54; 95% CI = −0.97 to −0.11; SDNN: −0.49; 95% CI = −0.93 to −0.05). HRV was inversely associated with CHD risk; for each 10-millisecond increase in SDNN or SDANN, there was a decrease in CHD risk of 9% (p = .023) and 12% (p = .006), respectively.
HRV did not play a major role in explaining why more optimistic women seem to be somewhat protected from CHD risk. Although hostility was inversely associated with HRV, its role in explaining the association between hostility and CHD risk remains to be established.
Hostility and optimism have been shown to predict coronary heart disease risk. Salmoirago-Blotcher et al. used data from the Women's Health Initiative to examine the role of heart rate variability in explaining this association. Heart rate variability was inversely associated with hostility, but not with optimism. Although heart rate variability was associated with higher risk of coronary heart disease, its role in explaining the association between these traits and coronary risk remains to be determined.
From the The Miriam Hospital (Salmoirago-Blotcher); Brown University School of Medicine (Salmoirago-Blotcher, Eaton), Providence, Rhode Island; University at Buffalo (Hovey), Buffalo, New York; University of Michigan (Andrews), Ann Arbor, Michigan; UC San Diego (Allison), La Jolla, California; University of Nevada (Brunner), Reno, Nevada; University of Iowa (Denburg), Iowa City, Iowa; Brown University School of Medicine and School of Public Health (Eaton), Providence, Rhode Island; UC Davis (Garcia), Davis, California; Ohio State University (Sealy-Jefferson), Columbus, Ohio; University of Washington (Zaslavsky), Seattle, Washington; Northwestern University (former affiliation), Evanston, Illinois; US Centers for Disease Control and Prevention (Kang), Atlanta, Georgia; UC San Francisco (López), San Francisco, California; Stony Brook University (Post), Stony Brook, New York; Vanderbilt University (Tindle), Nashville, Tennessee; and Albert Einstein College of Medicine (Wassertheil-Smoller), New York, New York.
Address correspondence to Elena Salmoirago-Blotcher, MD, PhD, Centers for Behavioral and Preventive Medicine, The Miriam Hospital, Coro Building, suite 309, One Hoppin St, Providence RI 02903. E-mail: Elena_Salmoirago-Blotcher@brown.edu
Received for publication March 21, 2018; revision received December 12, 2018.