Study finds night shift work linked to high risk of heart problems, women more susceptible

A study led by a team of international researchers reveals that people working in night shifts are more prone to developing heart-related diseases such as Atrial Fibrillation (AF), which makes a person go through an irregular and often abnormally fast heart rhythm. The study, published in the European Heart Journal, is considered the first to investigate the links between night shift work and AF. The researchers made their report based on the information collected from at least 2,83,657 people in the UK Biobank database. The study further says that night shift work is linked to an increased risk of heart disease, but not stroke or heart failure. 

Meanwhile, the researchers, led by Professor Yingli Lu, of Shanghai Ninth People's Hospital and Shanghai JiaoTong University School of Medicine, China, and Professor Lu Qi, of Tulane University School of Public Health and Tropical Medicine, USA, also investigated whether genetic predisposition to AF could play a role in the increased risk. Evaluating the overall genetic risk based on 166 genetic variations, they found that genetic risk levels did not affect the link between working night shifts and AF risk, no matter whether participants had a low, medium, or high genetic risk. Prof. Lu said that although a study like this cannot show a causal link between night shifts and Atrial Fibrillation and heart disease, the findings suggest that lifetime night shift work may increase the risk of these conditions. 

"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," he claimed. 

Women more susceptible to Atrial Fibrillation 

The researchers adjusted their analyses for factors affecting the results, such as age, sex, ethnicity, education, socioeconomic status, smoking, physical exercise, diet, body mass index, blood pressure, sleep duration and chronotype. The study shows that people who currently worked night shifts on a usual or permanent basis had a 12% increased risk of AF compared to people who only worked during the day, and the risk increased to 18% after ten or more years for those who work permanently in night shifts. Meanwhile, Prof Qi said that two interesting findings show that women were more susceptible to Atrial Fibrillation than men when working night shifts for more than ten years. Their risk increased significantly by 64% compared to day workers. 

"People reporting an ideal amount of physical activity of 150 minutes a week or more of moderate-intensity, 75 minutes a week or more of vigorous-intensity, or an equivalent combination, had a lower risk of atrial fibrillation than those with non-ideal physical activity when exposed to a lifetime of night shift work. Thus, women and less physically active people may benefit particularly from a reduction in night shift work," Prof Qi added. The researchers, however, also claimed that there were some limitations to the study that include several factors. They said that the people in UK Biobank were mainly white British, so it may not be possible to generalise the findings to other ethnic groups.

(With inputs from agency)

Image Credits: ANI/Representative