Life quality declines before diagnosis

A study examining patterns in the quality of life of Parkinson’ disease patients prior to diagnosis, shows declines in physical and mental health, pain, and emotional health beginning several years before the onset of the disease and continues after diagnosis.

Their results, recently reported in Journal of Parkinson’s Disease, describes a decline in physical function in Parkinson’s patients, beginning three years prior to diagnosis in men and seven and a half years prior to diagnosis in women.

Lead investigator, Natalia Palacios, of the Department of Nutrition, Harvard School of Public Health, says the decline continues at a rate five to seven times faster than the average yearly decline caused by normal ageing in individuals without the disease.

The study included 51,350 male health professionals enrolled in the Health Professionals Follow Up Study (HPFS) and 121,701 female registered nurses enrolled in the Nurses’ Health Study (NHS).

In both ongoing studies, participants completed biannual questionnaires about a variety of lifestyle characteristics and document the occurrence of major chronic disease.

In the NHS study, questionnaires measured health-related quality of life in eight areas: physical functioning, role limitations due to physical problems, role limitations due to emotional problems, vitality, bodily pain, social functioning, mental health, and general health perceptions. In the HPFS, only physical functioning was assessed.

Researchers identified 454 men and 414 women with Parkinson’s in the two cohorts. At seven and a half years prior to diagnosis, physical function among Parkinson’s cases, in both men and women, was comparable to that in the overall cohort.

In comparison, the average yearly decline in individuals without PD was 0.23 in men and 0.42 in women. Other measures of quality of life, available only in women, declined in a similar pattern.

Dr Palacios notes a strength of the study is the availability of prospective data on both Parkinson’s patients and a healthy comparison group, and the ability to chart the deterioration in functioning and quality of life over the whole study follow-up, which included many years prior to diagnosis.

“This result provides support to the notion that the pathological process leading to Parkinson’s disease may start several years before a diagnosis,” Dr Palacios said.

He added: “Our hope is that, with future research, biological markers of the disease process may be recognisable in this preclinical phase.”