Symptoms of Parkinson's disease typically start with non-motor symptoms that can begin long before the condition is diagnosed, new Harvard University research shows.
The first-of-its-kind study, published in the Journal of Parkinson's Disease, documented declines in patients’ physical and mental health – as well as pain and emotional problems – that started many years before the formal onset of the disease.
"We observed a decline in physical function in [Parkinson’s] 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," said lead researcher Natalia Palacios, of the Harvard School of Public Health. "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 is based on an analysis of the health records of 51,350 men enrolled in the Health Professionals Follow Up Study and 121,701 female participants in the Nurses' Health Study. Both are long-running studies that have been tracking health professions who fill out biannual questionnaires about a variety of lifestyle characteristics and document the occurrence of major chronic disease.
Researchers identified 454 men and 414 women with Parkinson’s who experienced notable mental and physical health declines years before their diagnoses.
"Our hope is that, with future research, biological markers of the disease process may be recognizable in this preclinical phase," said Palacios