Both current and lifetime night shift exposure are associated with increased risk of atrial fibrillation (AF), according to a study published online Aug. 10 in the European Heart Journal.
Ningjian Wang, from Shanghai Jiao Tong University, and colleagues assessed whether current and past night shift work was associated with incident AF and whether this association was modified by genetic vulnerability. Analysis included 283,657 participants (in paid employment or self-employed) without AF and 276,009 participants in the U.K. Biobank who were free of coronary heart disease, stroke, and heart failure at baseline.
The researchers found that over a median 10.4 years of follow-up, there was a significant increasing trend in the risk of incident AF from “day workers,” “shift but never/rarely night shifts,” and “some night shifts” to “usual/permanent night shifts” (P for trend = 0.013; hazard ratio [HR] for usual or permanent night shifts, 1.16; 95 percent confidence interval, 1.02 to 1.32). Participants with a duration over 10 years (HR, 1.18; 95 percent confidence interval, 0.99 to 1.40) and an average of three to eight nights/month frequency of night shift work exposure (HR, 1.22; 95 percent confidence interval, 1.02 to 1.45) showed higher AF risk than those who never worked nights over their lifetime. Genetic predisposition to AF did not modify these associations between current and lifetime night shifts and AF.
“Although a study like this cannot show a causal link between night shifts and atrial fibrillation and heart disease, our results suggest that current and lifetime night shift work may increase the risk of these conditions,” a coauthor said in a statement. “Our findings have public health implications for preventing atrial fibrillation. They suggest that reducing both the frequency and the duration of night shift work may be beneficial for the health of the heart and blood vessels.”