01/15/2009

Long working hours may be a risk factor for decline in cognitive function

Long working hours may predict decline in cognitive function, says recent
research, coordinated by the Finnish Institute of Occupational Health and
University College London. Results were published in the international American
Journal of Epidemiology. In Finland overwork is most common in information
technology, administration, and transport branches.

This is probably the first large prospective study on the association between
long working hours and cognitive function. Results indicate clearly that
advances attained by working overtime may be lost in terms of reduced wellbeing
and cognitive function of employees. "Therefore the disadvantages of overtime
work should be taken seriously", says Dr. Marianna Virtanen from the Finnish
Institute of Occupational Health.

It is yet not known why long working hours have adverse effect on cognitive
function. Several factors may contribute to the process, for example increased
sleeping problems, depression, unhealthy lifestyle and cardiovascular diseases.
All these factors together may have an effect to the brain function which
eventually is shown as a decline in cognitive function.

More than 2000 civil servants participated in the study
2214 middleaged British civil servants participated in the present study which
was a part of the Whitehall II study. They took five different cognitive tests
in 1997and again in 2002 When compared with employees with normal working hours
(35-40 per week), employees working very long hours (> 55 hours per week) and
those with an average length of working week (41hours) performed worse in a
vocabulary test already at the baseline study. At follow-up, both over-time
groups performed again worse in a vocabulary test and also had a declined test
score in a cognitive reasoning test.

The effects were cumulative; the longer the working week was the worse the test
results were. Employees with long working hours also had shorter sleeping
hours, reported more symptoms of depression and used more alcohol than those
with normal working hours. "We will go on with this study question in the
future. It is particularly important to examine whether the effects are
long-lasting and whether long working hours predict more serious conditions
such as dementia", says Professor Mika Kivimki.


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AplusA-online.de - Source: Finnish Institute of Occupational Health (FIOH)