Severe influenza doubles the odds that a person will develop Parkinson's disease later in life, according to University of British Columbia researchers.

However, the opposite is true for people who contracted a typical case of red measles as children -- they are 35 per cent less likely to develop Parkinson's, a nervous system disorder marked by slowness of movement, shaking, stiffness, and in the later stages, loss of balance.

The findings by researchers at UBC's School of Population and Public Health and the Pacific Parkinson's Research Centre, published online this month in the journal Movement Disorders, are based on interviews with 403 Parkinson's patients and 405 healthy people in British Columbia, Canada.

Lead author Anne Harris also examined whether occupational exposure to vibrations -- such as operating construction equipment -- had any effect on the risk of Parkinson's. In another study, published online this month by the American Journal of Epidemiology, she and her collaborators reported that occupational exposure actually decreased the risk of developing the disease by 33 percent, compared to people whose jobs involved no exposure.

Meanwhile, Harris found that those exposed to high-intensity vibrations -- for example, by driving snowmobiles, military tanks or high-speed boats -- had a consistently higher risk of developing Parkinson's than people whose jobs involved lower-intensity vibrations (for example, operating road vehicles). The elevated risk fell short of the statistical significance typically used to establish a correlation, but was strong and consistent enough to suggest an avenue for further study, Harris says.

"There are no cures or prevention programs for Parkinson's, in part because we still don't understand what triggers it in some people and not others," says Harris, who conducted the research while earning her doctorate at UBC. "This kind of painstaking epidemiological detective work is crucial in identifying the mechanisms that might be at work, allowing the development of effective prevention strategies."

Background information

Parkinson's disease results when brain cells that make the neurotransmitter dopamine are destroyed, preventing the brain from transmitting messages to muscles. The disease typically strikes people over age 50. Although some cases are genetic in origin, the cause for most cases of the disease is still unknown; possible explanations include repeated head trauma, or exposure to viruses or chemical compounds.

Treatment: There is no cure for Parkinson's, only medications to treat the symptoms.