Men working long hours ‘should be physically fit’
MedWire News: Unfit men who work long hours are at increased risk for ischemic heart disease (IHD) mortality, a 30-year follow-up study suggests.
The authors say that men who work long hours "should be physically fit" and note that their findings support the implementation of work-time limits for the benefit of public health.
It is already known that working long hours is associated with an increased risk for cardiovascular disease and this is recognized in the European Union's working hours directive. However, other countries including the United States do not have such regulations and dispute the link between working hours and health outcomes.
In this study, Andreas Holtermann (National Research Centre for the Working Environment, Copenhagen, Denmark) and team examined whether physical fitness influenced the association between work hours and cardiovascular mortality.
Their subjects were 5249 men from the Copenhagen Male Study who were aged 40-59 years, free of cardiovascular disease, and "gainfully employed" at enrolment. All were assessed for physical fitness and activity levels at baseline and followed-up for 30 years, during which time 587 (11.9%) had died from IHD.
Reporting their findings in the journal Heart, Holtermann et al reveal that the majority of participants (n=3404) worked between 41 and 45 hours per week while 638 worked no more than 40 hours per week and 922 worked for 46 hours per week or more.
Men who worked 41-45 hours/week had a 59% higher age-adjusted risk for IHD mortality but no greater risk for all-cause mortality as compared with men working 40 hours/week or less.
"The particularly high risk for IHD mortality among this subgroup is largely influenced by the over-representation of lower social class," the authors remark.
Among men with the lowest physical fitness, the fully adjusted hazard ratio for IHD mortality was 1.37 for those working 41-45 hours/week and 2.10 for those working >45 hours/week, as compared with those working 36-40 hours/week.
By contrast, among the most physically fit men, the fully adjusted hazard ratios were 0.74 and 0.84 for those working 41-45 and >45 hours/week, respectively, as compared with those working 36-40 hours/week.
"The hypothesis that level of physical fitness modifies the association between long work hours and risk of IHD mortality was supported," the authors conclude.
"This finding strengthens the present documentation of adverse health effects from long work hours, and supports that the lack of work time directives in some countries (eg, USA) may be a public health problem."
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By Joanna Lyford