People who work more than 40 hours a week for three decades or more are at greater risk of developing chronic, life-threatening diseases by the time they reach their 40s or 50s, according to a study published recently in the Journal of Occupational and Environmental Medicine (JOEM)
This finding is particularly relevant for women. Their increased risk begins to climb as soon as they pass the 40-hour-a-week mark, and then shoots up significantly at 50 hours, the study found.
“Women — especially women who have to juggle multiple roles — feel the effects of intensive work experiences and that can set the table for a variety of illnesses and disability,” said Allard Dembe, the study’s lead author and a professor of health services management and policy at Ohio State University, in a released statement.
Dembe and his co-author, Xiaoxi Yao, now a research fellow at the Mayo Clinic in Rochester, used data from almost 7,500 American adults who had participated in the National Longitudinal Survey of Youth 1979, which tracked the job history and health status of adults born between 1957 and 1964 over a 32-year period.
The researchers looked specifically at whether the survey’s respondents had developed one or more of eight chronic diseases: heart disease, non-skin cancer, arthritis/rheumatism, diabetes, chronic lung disease (including bronchitis or emphysema), asthma, depression or high blood pressure.
They found that most of the respondents who reported having full-time jobs tended to work longer than the “conventional” 40-hour workweek. Some 56 percent said they averaged 41-50 hours per week, while 13 percent said they put in an average of 51-60 hours.
Three percent reported averaging 60 hours per week or more.
Incidence of illness
Dembe and Yao then compared those workweeks with the development of chronic disease. They found that working long hours was “significantly associated” with an elevated risk for four types of chronic conditions: non-skin cancer, heart disease, arthritis and diabetes.
For example, people who worked 51 or more hours a week were 1.7 times more likely to have developed heart disease and 1.6 times more likely to have developed diabetes by their 40s and 50s than their full-time working peers who averaged shorter workweeks.
They were also more likely to develop non-skin cancer (2.0 times higher at 51-60 hours per week and 2.8 times higher at more than 60 hours per week) and arthritis (1.9 times higher at 51-60 hours per week and 2.9 at more than 60 hours per week).
A gender gap
Those results are interesting. As Dembe and Yao point out in their study, previous studies have found links between long working hours and heart disease, but the findings regarding other chronic conditions have tended to be inconclusive and contradictory.
But most “striking,” say Dembe and Yao, was the current study’s findings regarding gender.
“For men, long hours of work appeared only to affect the risk of contracting arthritis,” they write. “No adverse effects were found for other conditions. In fact, working moderately long hours (41-50 hours per week) was actually associated with less risk of contracting heart disease, chronic lung disease, or depression.”
By contrast, “[w]omen consistently showed a markedly strong relationship between long work hours and the prevalence of heart disease, non-skin cancer, arthritis, and diabetes,” they add.
And, unlike with men, women who worked long hours (51-60 hours per week) had a slightly elevated risk for asthma and high blood pressure.
Caveats and implications
This study shows only a correlation between working long hours and an increased risk for chronic disease, not a cause-and-effect. Other factors not related to hours worked may explain the study’s findings.
In addition, the results rely on average hours worked per week. It’s not clear if the health risk changes if people are able to cut back on their hours as they grow older — or if the long hours are discretionary rather than mandatory.
“It could make a difference,” said Dembe. “You might still be working hard, but the fact that it’s your choice might help you stay healthier.”
Still, the study’s findings are troubling, particularly for working women. Six percent of women in the U.S. work 50 or more hours a week, and almost 2 percent work more than 60 hours a week, according to the Bureau of Labor Statistics.
“Averaged over many years, women working more than 60 hours per week have a nearly three-fold risk of chronic disease, including heart disease, non-skin cancer, arthritis, and diabetes,” write Dembe and Yao.
The researchers call on employers and safety officials, as well as workers, to take note and make workplace-related changes, particularly the adopting of work schedules with fewer hours.
“People don’t think that much about how their early work experiences affect them down the road,” stated Dembe. “Women in their 20s, 30s and 40s are setting themselves up for problems later in life.”
FMI: You’ll find an abstract of the study on JOEM’s website, but, unfortunately, the full study is behind a paywall.