Risk for CVD Increased for Individuals With Definite Evening Chronotype

WEDNESDAY, Jan. 28, 2026 (HealthDay News) -- Individuals with definite evening chronotype have a higher risk for cardiovascular disease (CVD), with most of the association mediated by Life's Essential 8 (LE8), calculated from eight CVD risk factors, according to a study published online Jan. 28 in the Journal of the American Heart Association.Sina Kianersi, Ph.D., from Brigham and Women's Hospital and Harvard Medical School in Boston, and colleagues conducted a prospective study involving 322,777 U.K. Biobank participants aged 39 to 74 years, free of known CVD, to examine the association between chronotype, self-reported using a single representative question, and CVD risk. The role of LE8 in the chronotype-CVD association was assessed by splitting the total effect into natural direct effect (independent of LE8) and natural indirect effect (mediated by LE8).The researchers found that compared with those with an intermediate chronotype, participants with a definite evening chronotype had a 79 percent higher prevalence of an overall poor LE8 score (<50 points). There were 17,584 incident CVD events during a median 13.8 years of follow-up. The hazard ratios for total CVD were 1.03 (95 percent confidence interval, 0.998 to 1.07) and 1.16 (95 percent confidence interval, 1.10 to 1.22) for the definite morning and definite evening chronotypes, respectively, compared with the intermediate chronotype. Comparing the definite evening with the intermediate chronotype, LE8 explained 75 percent of the association with CVD (natural indirect effect; hazard ratio, 1.11; 95 percent confidence interval, 1.09 to 1.13)."Evening people may be more likely to have behaviors that can affect cardiovascular health, such as poorer diet quality, smoking and inadequate or irregular sleep," Kianersi said in a statement.One author disclosed ties to the pharmaceutical industry.Abstract/Full Text.Sign up for our weekly HealthDay newsletter