more: "People who work in rotating night shifts have a lower risk of Parkinson's disease, results of a study published in the April issue of the American Journal of Epidemiology indicate. Conversely, a longer average duration of sleep is linked to an increased risk.

'Working rotating night shift 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 develop Parkinson's disease has not been investigated.

The researchers therefore examined the association between working rotating night shifts and the risk of Parkinson's disease using data from the U.S. Nurses' Health Study (1988 to 2000), which enrolled 84,794 female nurses.
Nurses who reported at least 15 years of night shift work were older and more likely to be current smokers and NSAID users compared to 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 tended to sleep slightly less than non-night shift workers....."
[Abstract - Medscape]