Night shift work is linked to increased risk of heart problems

Date:
August 16, 2021
Source:
European Society of Cardiology
Summary:
Using data from over 283,600 people in UK Biobank, researchers
have found that people who work night shifts are at increased risk
of developing an irregular and often abnormally fast heart rhythm
called atrial fibrillation, and they are also at an increased risk
of heart disease.

Women and people who don't exercise regularly are most at risk.



FULL STORY ========================================================================== People who work night shifts are at increased risk of developing
an irregular and often abnormally fast heart rhythm called atrial
fibrillation (AF), according to research published in the European
Heart Journal.


==========================================================================
The study is the first to investigate the links between night shift work
and AF. Using information from 283,657 people in the UK Biobank database, researchers found that the longer and more frequently that people worked
night shifts over their lifetimes, the greater their risk of AF. Night
shift work was also linked to an increased risk of heart disease, but
not to stroke or heart failure.

In addition, the researchers, led by Professor Yingli Lu, of Shanghai
Ninth People's Hospital and Shanghai JiaoTong University School of
Medicine, Shanghai, China, and Professor Lu Qi, of Tulane University
School of Public Health and Tropical Medicine, New Orleans, USA,
investigated whether genetic predisposition to AF could play a role in
the increased risk. They evaluated the overall genetic risk on the basis
of 166 genetic variations known to be associated with the condition but
found that the genetic risk levels did not affect the link between working night shifts and AF risk, regardless of whether participants had a low,
medium or high genetic risk.

Prof. Lu said: "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.

"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." The study included 286,353 people who were
in paid employment or self-employed.

A total of 283,657 of these participants did not have AF when they
enrolled in UK Biobank, and 276,009 did not have heart failure or
stroke. Information on genetic variants was available for 193,819
participants without AF, and 75,391 of them answered in-depth questions
about their lifetime employment in a questionnaire sent out in 2015. Among
the participants free of heart disease and stroke when they joined the
study, 73,986 provided information on their employment history. During
an average follow-up time of over ten years, there were 5,777 AF cases.



==========================================================================
The researchers adjusted their analyses for factors that could affect the results, such as age, sex, ethnicity, education, socioeconomic status,
smoking, physical exercise, diet, body mass index, blood pressure,
sleep duration and chronotype (whether someone was a 'morning' or an
'evening' person).

They found 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. The risk increased to 18% after ten or more years
for those who had a lifetime duration of night shifts. Among people who
worked an average of three to eight night shifts a month for ten years
or more, the risk of AF increased to 22% compared to daytime workers.

Among participants currently working night shifts, or working night
shifts for ten or more years, or working a lifetime of three to eight
night shifts a month, the risk of coronary heart disease increased by 22%,
37% and 35% respectively compared to daytime workers.

Prof. Qi said: "There were two more interesting findings. We found
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." A strength
of the study is its size, with detailed information on over 283,000
people. In addition, it is the first study to link these data with
genetic information in a population that also has detailed histories
available on current shift work and lifetime employment.

Limitations of the study include the fact that it cannot show shift
work causes heart problems, only that it is associated with them; some
cases of atrial fibrillation may have been missed; lifetime employment
was assessed only when people joined UK Biobank, was self-reported and, therefore, may have changed or be prone to some errors; there may be
unknown factors that might affect the results; and the people in UK
Biobank were mainly white British and so it may not be possible to
generalise the findings to other ethnic groups.

Prof. Lu said: "We plan to analyse the association between night shift
work and atrial fibrillation in different groups of people. This may
strengthen the reliability of these results and serve as a warning to
groups working in certain types of occupations to get their hearts
checked early if they feel any pain or discomfort in their chests." ========================================================================== Story Source: Materials provided by European_Society_of_Cardiology. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Ningjian Wang, Ying Sun, Haojie Zhang, Bin Wang, Chi Chen,
Yuying Wang,
Jie Chen, Xiao Tan, Jihui Zhang, Fangzhen Xia, Lu Qi, Yingli
Lu. Long- term night shift work is associated with the risk of
atrial fibrillation and coronary heart disease. European Heart
Journal, 2021; DOI: 10.1093/ eurheartj/ehab505 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210816111941.htm

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