Age-, gender-, and socioeconomic status-specific incidence of Parkinson's disease and parkinsonism in North East Scotland: The PINE study

https://doi.org/10.1016/j.parkreldis.2013.01.014Get rights and content

Abstract

There have been few high quality incidence studies of Parkinson's disease (PD). We measured age-, gender- and socioeconomic-specific incidence rates for parkinsonism and PD in north-east Scotland, and compared our results with those of previous high quality studies.

Incident patients were identified prospectively over three years by several overlapping methods from primary care practices (total population 311,357). Parkinsonism was diagnosed if patients had two or more cardinal motor signs. Drug-induced parkinsonism was excluded. Patients had yearly follow-up to improve diagnostic accuracy.

Incidence rates using clinical diagnosis at latest follow-up were calculated for all parkinsonism and for PD by age, gender and socioeconomic status. Meta-analysis with similar studies was performed.

Of 377 patients identified at baseline with possible or probable parkinsonism, 363 were confirmed as incident patients after median follow-up of 26 months (mean age 74.8 years, SD 9.8; 61% men). The crude annual incidence of parkinsonism was 28.7 per 100,000 (95% confidence interval (CI) 25.7–31.8) and PD 17.9 per 100,000 (95% CI 15.5–20.4). PD was more common in men (age-adjusted male to female ratio 1.87:1, 95% CI 1.55–2.23) but there was no difference by socioeconomic status. Meta-analysis of 12 studies showed an incidence of PD (adjusted to the 1990 Scottish population) of 14.6 per 100,000 (95% CI 12.2–17.3) with considerable heterogeneity (I2 95%), partially explained by population size and recruitment duration.

The incidence of PD was similar to other high quality studies. The incidence of PD was not affected by socioeconomic status.

Introduction

Knowledge of the incidence of a condition is important both in terms of planning the allocation of healthcare resources and, when compared between populations, in identifying potential aetiological factors. A systematic review of incidence studies of Parkinson's disease (PD) carried out in 2001 [1], found only five comparable, high quality studies, none of which had prospective follow-up of the incident cohort. Follow-up is required to improve the accuracy of the diagnosis of PD, which may be poor in the early stages of the condition [2], [3] and to provide the most accurate and representative data on prognosis.

We undertook a large, two-phase, prospective, community-based incidence study of Parkinson's disease and other degenerative or vascular parkinsonian conditions with planned long-term follow-up of the incident cohort in order to calculate age-gender specific incidence figures. Further, as the role of socioeconomic status in the aetiology of PD has not been extensively studied, we aimed to calculate incidence by socioeconomic group. A previous study in the same area carried out 20 years previously found a prevalence of around 165 per 100,000 but did not report a figure for incidence [4].

Section snippets

Methods

The Parkinsonism Incidence in North-East Scotland (PINE) study attempted to identify all incident patients with degenerative or vascular parkinsonism in a well-defined population in and around Aberdeen, UK. This was done in two phases: a pilot phase in 148,600 people registered with 18 general (primary care) practices over 18 months from November 2002, and the main phase extended to 317,357 people from all 37 general practices in the area over 36 months from April 2006 (Fig. S1). Everyone in

Results

The study profile is shown in Fig. 1. Out of 828 potentially incident patients assessed, 697 were assessed in the study outpatient clinic, 41 (mean age 81.0 (standard deviation (SD) 7.7), 61% of whom became incident patients) were assessed at home or in their nursing home and a further 72 (mean age 79.0 (SD 9.2); 65% became incident patients) were initially assessed as hospital inpatients. All but eighteen patients (2% of those identified) were assessed in person by a study doctor. Four died

Discussion

This study found the crude incidence of clinically probable PD in the North East of Scotland to be 17.9/100,000/year, and of clinically probable vascular or neurodegenerative parkinsonism to be 28.7/100,000/year. These are likely to be underestimates given that some older patients remain undiagnosed in the community [6], [7].

As expected, the incidence both of PD and parkinsonism was higher in men [30] and increased with age, peaking in the 9th decade. However, given there were only 5644.5

Conclusion

This study found a similar incidence of PD and parkinsonism in north-east Scotland to the few other high quality studies with no variation by socioeconomic status. Ongoing follow-up of this and other incident cohorts will yield important new information regarding the prognosis of these conditions, which up until now has largely been based on younger non-representative cohorts of patients. Further high quality incidence studies are required especially from Asia, North America and the southern

Author contributions

R. Caslake performed the literature search and updated the systematic review, recruited participants and collected data, analysed data and wrote the first draft of the paper.

K. Taylor performed the initial systematic review, recruited patients and collected data.

N. Scott provided statistical support.

J. Gordon and C. Harris recruited participants and collected data and performed electronic database searching.

K. Wilde provided IT and data management support.

A. Murray provided diagnostic radiology

Funders

Parkinson's UK, Doris Hillier BMA Award, BUPA Foundation, SPRING, NHS Grampian Endowments.

Conflicts of interest

None declared.

Acknowledgements

We thank our funders (Parkinson's UK, Doris Hillier BMA Award, the BUPA Foundation, SPRING, NHS Grampian Endowments), Susan Kilpatrick for secretarial support, and all the patients and general practices that took part.

References (36)

  • K.S. Taylor et al.

    Screening for undiagnosed parkinsonism in people aged 65 years and over in the community

    Parkinsonism Relat Disord

    (2006)
  • D. Twelves et al.

    Systematic review of incidence studies of Parkinson's disease

    Mov Disord

    (2003)
  • A.H. Rajput et al.

    Accuracy of clinical diagnosis in parkinsonism–a prospective study

    Can J Neurol Sci

    (1991)
  • R. Caslake et al.

    Changes in diagnosis with follow-up in an incident cohort of patients with parkinsonism

    J Neurol Neurosurg Psychiatr

    (2008)
  • W.J. Mutch et al.

    Parkinson's disease in a Scottish city

    BMJ

    (1986)
  • K.S.M. Taylor et al.

    Pilot study of the incidence and prognosis of degenerative Parkinsonian disorders in Aberdeen, United Kingdom: methods and preliminary results

    Mov Disord

    (2006)
  • K.S. Taylor et al.

    Screening for undiagnosed parkinsonism among older people in general practice

    Age Ageing

    (2005)
  • S. Fahn et al.

    Members of the UPDRS Development Committee. Unified Parkinson's disease rating scale

  • K.R. Chaudhuri et al.

    Long duration asymmetrical postural tremor is likely to predict development of Parkinson's disease and not essential tremor: clinical follow up study of 13 cases

    J Neurol Neurosurg Psychiatr

    (2005)
  • A.J. Hughes et al.

    Accuracy of clinical diagnosis of idiopathic Parkinson's disease. A clinico-pathological study of 100 cases

    J Neurol Neurosurg Psychiatr

    (1992)
  • I.G. McKeith et al.

    Consortium on DLB. Diagnosis and management of dementia with Lewy bodies: third report of the DLB consortium

    Neurology

    (2005)
  • S. Gilman et al.

    Second consensus statement on the diagnosis of multiple system atrophy

    Neurology

    (2008)
  • I. Litvan et al.

    Clinical research criteria for the diagnosis of progressive supranuclear palsy (Steele–Richardson–Olszewski syndrome): report of the NINDS-SPSP International Workshop

    Neurology

    (1996)
  • J.C.M. Zijlmans et al.

    Clinicopathological investigation of vascular parkinsonism, including clinical criteria for diagnosis

    Mov Disord

    (2004)
  • A.E. Lang et al.

    Cortico-basal ganglionic degeneration

  • D.E. Riley et al.

    Clinical diagnostic criteria

  • V. Carstairs et al.

    Deprivation and health in Scotland

    Health Bull

    (1990)
  • P. McLoone

    Carstairs scores for Scottish postcode sectors from the 2001 Census

    (2004)
  • Cited by (75)

    • Update: Descriptive epidemiology of Parkinson disease

      2024, Parkinsonism and Related Disorders
    • Disparities in diagnosis, treatment and survival between Black and White Parkinson patients

      2021, Parkinsonism and Related Disorders
      Citation Excerpt :

      It also allows further assessments on important underlying factors associated with medication use and survival. We found no male predominance among Black PD patients, in contrast to White patients here and in other studies predominantly on White population [20,21]. It is unclear whether this difference reflects a biological fact or others.

    View all citing articles on Scopus
    View full text