Occupational Characteristics and Patterns as Risk Factors for Parkinson's Disease: A Case Control Study

Occupation and Parkinson disease in the Women's Health Initiative Observational Study

INTRODUCTION

There is a lack of consistent study findings on associations between workplace exposures and the risk of Parkinson disease (PD) and a paucity of such data on women. We assessed PD risk among occupational groups to derive insights about potential occupation-specific exposures in a large cohort of women.

METHODS

The Women's Health Initiative Observational Study (WHI-OS) is a prospective cohort that enrolled 91 627 postmenopausal women, 50 to 79 years of age, from 01 October 1993 through 31 December 1998, at 40 clinical centers across the United States, with average follow-up interval of 11 years. These women reported up to three paid jobs, held the longest since age 18; these jobs were coded and duration of employment calculated. We defined a case by self-report of doctor-diagnosed PD (at baseline or follow-up), death attributed to PD, or taking medication consistent with PD.

RESULTS

Among 2590 PD cases, we found evidence of excess risk among "counselors, social workers, and other community and social service specialists," and there was a suggestion of increased in risk among postsecondary teachers, and "building and grounds cleaning and maintenance" workers. There was also evidence of a deficit in risk among women who worked in sales. Results according to ever-employed and job duration were similar, except for evidence of excess risk among "health technologists and technicians" with more than 20 years of employment. Longer duration of life on a farm was associated with higher risk.

CONCLUSION

Our findings paint a largely reassuring picture of occupational risks for PD among US women.

Reduced workforce participation 5 years prior to first Parkinson's disease sick-leave

The importance of understanding the prodromal phase of Parkinson’s disease (PD) by systematic recording of prediagnostic symptoms and reductions in body functions has been highlighted. The aim of this study was to investigate whether persons later diagnosed with PD exhibit increased physician-certified sickness absence 1, 2, and 5 years prior to a first sick-leave episode attributed to PD. A case-control study was performed to analyze data from all nontrivial (exceeding 14 days) sick-leave episodes in Sweden between 2008 and 2014. The 537 incident PD sick-leave episodes were identified as PD sick-leave cases and compared to 537 sick-leave controls identified by matching age, sex, and date of the first day of the sick-leave episode. The total sickness absence and sickness absence due to musculoskeletal diagnoses were found to be increased among the PD sick-leave cases from 5 years prior to the first sick-leave episode ascribed to PD when compared to the controls. No differences between PD sick-leave cases and sick-leave controls were found with regard to mental and behavioral diagnoses. We conclude that the capacity to participate in working life is reduced already at the early prediagnostic stages of PD. This finding can be used as a basis for further research into the process of identifying individuals at risk for developing PD, particularly in combination with further investigation into biochemical, genetic, and imaging biomarkers.

A Swedish study shows that Parkinson’s disease (PD) patients had more sick-leave episodes in the years before diagnosis than matched controls not diagnosed with PD. There is growing evidence that prior PD diagnosis, patients experience a variety of nonmotor symptoms and subtle motor signs. Further understanding these symptoms could prompt earlier therapeutic intervention and increase the likelihood of slowing down or even halting disease progression. A study led by Jonathan Timpka at Lund University examined the sickness leave history of 537 workers 1, 2 and 5 years before a first sick-leave episode due to PD. These workers took more sick-leave due to musculoskeletal symptoms, but not due to mental or behavioral issues, than the control group. These findings highlight a potential effect of preclinical PD on patients’ ability to work.