NEW YORK (Reuters Health) – People who work rotating night
shifts appear to have a lower risk of Parkinson’s disease, the
results of a study published in the American Journal of
Epidemiology indicate. Conversely, an increased risk of
developing this condition is linked to a longer average
duration of sleep.
“Working rotating night shifts disrupts circadian rhythms
and may have a wide range of physiologic, psychological and
social effects on shift workers,” Dr. Honglei Chen, of the
National Institutes of Health, Research Triangle Park, North
Carolina, and colleagues write.
“In previous studies, shift work has been linked to higher
risks of some chronic diseases, including cardiovascular
disease and certain types of cancers,” they note, but any
effect on the risk of developing Parkinson’s disease has not
been investigated.
The researchers therefore evaluated data from the U.S.
Nurses’ Health Study, which enrolled 84,794 female nurses, to
see if there was an association between working rotating night
shifts and Parkinson’s disease risk.
Nurses who reported at least 15 years of night shift work
were older and more likely to be current smokers and users of
nonsteroidal antiinflammatory drugs (NSAID), such as ibuprofen
or naproxen, compared with those who never worked rotating
night shifts.
Night shift workers also tended to drink more coffee but
less alcohol and to have a higher body mass index. Women who
worked night shifts slept slightly less than non-night shift
workers.
A total of 181 cases of Parkinson’s disease were reported
between1988 and 2000. The risk of Parkinson’s disease was
50-percent lower among women who had at least 15 years of night
shift work compared with those who never worked rotating night
shifts.
After accounting for differences in age and smoking status,
the investigators found that a longer sleep duration was
associated with a higher risk of Parkinson’s disease. Compared
with nurses who slept no more than 6 hours per day, those who
slept 9 or more hours per day had a 84-percent increased risk.
Plausible biologic explanations for these results are
lacking, Chen’s team points out. They note that shift work has
been associated with modest increases in blood levels of
estradiol and uric acid, “both of which may be protective
against Parkinson’s disease.”
Conversely, they suggest that the data could be interpreted
as showing that a “low tolerance for night shift work is an
early marker of Parkinson’s disease.”
SOURCE: American Journal of Epidemiology, April 2006.
Comments