Symptoms may precede Parkinson's diagnosis BOSTON, July 2 (UPI) -- There is growing evidence Parkinson's disease often starts with non-motor symptoms that precede diagnosis by several years, U.S. researchers found. Lead investigator Natalia Palacios of the Harvard School of Public Health and colleagues examined patterns in the quality-of-life of Parkinson' disease patients prior to diagnosis. The researchers documented declines in physical and mental health, as well as pain and emotional health, beginning several years before the onset of the disease and continuing thereafter. "We observed a decline in physical function in PD patients relative to their healthy counterparts beginning three years prior to diagnosis in men and seven and a half years prior to diagnosis in women," Palacios said in a statement. The decline continues at a rate that is five to seven times faster than the average yearly decline caused by normal aging in individuals without the disease. The study involved 51,350 male health professionals enrolled in the Health Professionals Follow Up Study and 121,701 female registered nurses enrolled in the Nurses' Health Study. Researchers identified 454 men and 414 women with Parkinson's disease in the two groups. The study, published in the Journal of Parkinson's Disease, found a decline began approximately three years prior to diagnosis in men and approximately 7.5 years prior to diagnosis in women.