BACKGROUND: The etiology of Parkinson's disease (PD) remains unclear, and environmental risk-factors such as occupation have attracted interest. OBJECTIVE: The goal was to investigate occupational complexity in relation to PD. METHODS: We conducted a population-based cohort study based on the Swedish Twin Registry that included 28,778 twins born between 1886 and 1950. We identified 433 PD cases during the study period. Data on occupation were collected from either the 1970 or 1980 Swedish census, and occupational complexity was assessed via a job exposure matrix. Cox proportional hazard regression analyses with age as the underlying time scale were used to assess PD risk as a function of the three domains of occupational complexity: data, people, and things. Sex and smoking were included as covariates. Analyses stratified by twin pair were conducted to test for confounding by familial factors. RESULTS: High occupational complexity with data and people was associated with increased risk overall (Hazard Ratio [HR] = 1.07, 95% confidence interval [CI] 1.02-1.14, and HR = 1.10, 95% CI 1.01-1.21, respectively), and in men (HR = 1.08, 95% CI 1.01-1.16, and HR = 1.15, 95% CI 1.03-1.28, respectively). Complexity with things was not associated with risk of PD. When the analyses were stratified by twin pair, the HRs for occupational complexity with data and people were attenuated in men. CONCLUSIONS: High complexity of work with data and people is related to increased risk of PD, particularly in men. The attenuation of risk observed in the twin pair-stratified analyses suggests that the association may partly be explained by familial factors, such as inherited traits contributing to occupational selection or other factors shared by twins.

Karolinska Institutet Department of Medical Epidemiology and Biostatistics Stockholm Sweden

Karolinska Institutet Department of Medical Epidemiology and Biostatistics Stockholm Sweden; Karolinska Institutet Department of Clinical Neurosciences Stockholm Sweden

Karolinska Institutet Department of Medical Epidemiology and Biostatistics Stockholm Sweden; University of Southern California Department of Psychology Los Angeles California United States of America

University of South Florida School of Aging Studies Tampa Florida United States of America

University of South Florida School of Aging Studies Tampa Florida United States of America; St Anne's University Hospital International Research Center Brno Czech Republic

Zobrazit více v PubMed

de Lau LML, Breteler MMB (2006) Epidemiology of Parkinson's disease. The Lancet: Neurology 5: 525–535. PubMed

Dorsey ER, Constantinescu R, Thompson JP, Biglan KM, Holloway RG, et al. (2007) Projected number of people with Parkinson disease in the most populous nations, 2005 through 2030. Neurology 68: 384–386. PubMed

Wirdefeldt K, Gatz M, Reynolds CA, Prescott CA, Pederson NL (2011) Heritability of Parkinson's disease in Swedish twins: A longitudinal study. Neurobiology of Aging 32: e1–e8. PubMed PMC

Frigerio R, Elbaz A, Sanfit KR, Peterson BJ, Bower JH, et al. (2005) Education and occupations preceding Parkinson disease. Neurology 65: 1575–1583. PubMed

Tanner CM, Ross GW, Jewell SA, Hauser RA, Jankovic J, et al. (2009) Occupation and risk of Parkinsonism: A multicenter case-control study. Archives of Neurology 66: 1106–1113. PubMed

Li X, Sundquist J, Sundquist K (2009) Socioeconomic and occupational groups and Parkinson's disease: A nationwide study based on hospitalizations in Sweden. International Archives of Occupational and Environmetal Health 82: 235–241. PubMed

Karp A, Kareholt I, Qui C, Bellander T, Winblad B, et al. (2004) Relation of education and occupation-based socioeconomic status to incident Alzheimer's disease. American Journal of Epidemiology 159: 175–183. PubMed

Andel R, Crowe M, Pederson NL, Mortimer JA, Crimmins E, et al. (2005) Complexity of work and risk of Alzheimer's disease: A population-based study of Swedish twins. Journals of Gerontology Series B, Psychological Sciences and Social Sciences 60B: 251–258. PubMed

Wirdefeldt K, Gatz M, Pawitan Y, Pederson NL (2005) Risk and protective factors for Parkinson's disease: A study in Swedish twins. Annals of Neurology 57: 27–33. PubMed

Wirdefeldt K, Adami H, Cole P, Trichopoulos D, Mandel J (2011) Epidemiology of etiology of Parkinson's disease: A review of the evidence. European Journal of Epidemiology 26: 1–58. PubMed

Kohn ML, Schooler C (1983) Work and personality: An inquiry into the impact of social stratification. Norwood, NJ: Ablex Publishing Corporation.

Lichtenstein P, De Faire U, Floderus B, Svartengren M, Svedberg P, et al. (2002) The Swedish Twin Registry: A unique source for clinical, epidemiological, and genetic studies. Journal of Internal Medicine 252: 184–205. PubMed

International Labour Organization International Standard Classification of Occupations.

Miller AR, Treiman DJ, Cain PS, Roos PA (1980) Work, jobs, and occupations: A critical review of occupational titles. Washington, DC: National Academy Press.

Cain PS, Treiman DJ (1981) The Dictionary of Occupational Titles as a source of occupational data. American Sociological Review 46: 253–278.

National Board of Health and Welfare (2012) The National Patient Register.

National Board of Health and Welfare (2012) The Cause of Death Register.

Ludvigsson JF, Andersson E, Ekbom A, Feychting M, Kim J, et al. (2011) External review and validation of the Swedish national inpatient register. BMC Public Health 11: 450. PubMed PMC

Feldman AL, Johansson AL, Gatz M, Flensburg M, Petzinger GM, et al. (2012) Accuracy and sensitivity of Parkinsonian disorder diagnoses in two Swedish national health registers. Neuroepidemiology 38: 186–193. PubMed PMC

SAS Institute The SAS System for Windows, release 9.2. Cary, NC.

von Campenhausen S, Bornschein B, Wixk R, Botzel K, Sampaio C, et al. (2005) Prevalence and incidence of Parkinson's disease in Europe. European Neuropsychopharmacology 15: 473–490. PubMed

Menza MM (2000) The personality associated with Parkinson's disease. Current Psychiatry Reports 2: 421–426. PubMed

Tomer R, Aharon-Peretz J (2003) Novelty seeking and harm avoidance in Parkinson's disease: Effects of asymmetric dopamine deficiency. Journal of Neurology, Neurosurgery & Psychiatry 75: 972–975. PubMed PMC

Kaasinen V, Aalto S, Nagren K, Rinne JO (2004) Insular dopamine D2 receptors and novelty seeking personality in Parkinson's disease. Movement Disorders 19: 1348–1351. PubMed

Gatto NM, Bordelon Y, Gatz M, Ritz B (2011) Personality characterisitcs and motor skills attributed to occupations in Parkinson Disease. Cognitive and Behavioral Neurology 24: 18–25. PubMed PMC

Allen TD, Poteet ML, Burroughs SM (1997) The mentor's perspective: A qualitative inquiry and future research agenda. Journal of Vocational Behavior 51: 70–89.

Allen TD, Poteet ML, Russel JEA, Dobbins GH (1997) A field study of factors related to supervisors' willingness to mentor others. Journal of Vocational Behavior 50: 1–22.

Wood GE, Young LT, Reagan LP, Chen B, McEwen BS (2004) Stress-induced structural remodeling in hippocampus: prevention by litium treatment. PNAS 101: 3973–3978. PubMed PMC

Mitchell IJ, Clarke CE, Boyce S, Robertson RG, Peggs D, et al. (1989) Neural mechanisms underlying parkinsonian symptoms based upon regional uptake of 2-deoxxyglucose in monkeys exposed to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Neuroscience 32: 213–226. PubMed

Oyer P (2008) Wage structure and labor mobility in Sweden, 1970–1990. In: E. P Lazear and K. L Shaw, editors. The Structure of Wage, an International Comparison. Chicago, IL: University of Chicago Press. pp. 419–448.

Van Doorslaer E, Masseria C, Koolman X (2006) Inequalities in access to medical care by income in developed countries. Canadian Medical Association Journal 174: 177–183. PubMed PMC