A Population-Based Study of Parkinsonism in an Amish Community

Abstract

Background: Parkinson’s disease (PD) is a neurodegenerative disorder with unknown cause. Genetic mutations account for a minority of cases but the role of environmental factors is unclear. Methods: We performed a population-based screening for PD in subjects in an Amish community over age 60. PD was diagnosed using standard clinical criteria and the Unified Parkinson Disease Rating Scale motor subsection 3 (UPDRS3). Community prevalence was calculated. We constructed a community pedigree and calculated kinship coefficients, a measure of relatedness between 2 subjects, for every pair of subjects in diagnostic categories: clinically definite PD, UPDRS3 score >9, Mini-Mental State Exam (MMSE) score <25, and normal. Results: Of 262 eligible subjects, 213 agreed to participate, 15 had PD, 43 had MMSE <25, 73 had UPDRS3 >9. The prevalence of PD was 5,703/100,000 with increasing prevalence in every decade of age. Excluding first-degree relatives, normal subjects were more related to each other (0.0102, SD = 0.0266) than subjects with clinically definite PD (0.0054, SD = 0.0100; p = 0.00003), subjects with UPDRS >9 (0.0076, SD = 0.0155; p = 0.00001), and subjects with MMSE <25 (0.0090, SD = 0.0180; p = 0.00003). Conclusions: PD and parkinsonian signs are common in this population and the prevalence increases with age. The finding that subjects with PD were not more related than normal subjects suggests that environmental factors may contribute to the parkinsonian phenotype in this community.

Parkinson’s disease-related motor and non-motor symptoms are not more prevalent in the Lancaster Amish

“…Contrary to our initial hypothesis based on results from other Amish communities [4,5], we found that the prevalence of clinical PD diagnoses (1.2%) to be similar to that reported in the general U.S. older adult populations [6]. For those without a PD diagnoses, the prevalence of motor symptoms defined as positive for at least one nine-item motor questionnaire to screen for PD (10.5%) is not higher than the general population based on based on face-face exam in older populations (16%-48%) [15,16] farming, manual labor) that may decrease constipation [10].…”

“…In a community-based survey of 4,369 Amish in Missouri, Racette et al [4] reported that 7% of 213 participants older than 60 years met the criteria of clinical diagnosis of PD and 35% had subclinical parkinsonian signs based on Unified PD Rating Scale-Part III motor (UPDRS) exams. Similarly, Cummings et al [5] reported a prevalence of ~5% (33/647) for clinical PD in Amish subjects ≥60 years old from Indiana and Ohio.…”

Association between Various Brain Pathologies and Gait Disturbance

“…GM volume has also been associated with more severe measures of motor dysfunction (bradykinesia and gait disturbance), which is prevalent even among older adults without neurological conditions [42,51,52]. Among 307 community-dwelling older adults (mean age=83) without PD, smaller GM sensorimotor cortical and posterior parietal lobe volumes were associated with bradykinesia and gait disturbance.…”

Associations of welding and manganese exposure with Parkinson disease

“…Because the method of ascertainment of cases was different in these studies, the obtained prevalence ratio (10.19) reported in this study is unlikely to be valid. A more recent study by the same investigators 56 showed that utilization of a similar method to that used to assess parkinsonism in Alabama welders generated a very high rate in the general population as well, bringing into question the conclusion from the Alabama welding study that welders have higher risk of PD.…”