Case ascertainment uncertainties in prevalence surveys of Parkinson's disease

Using unpublished data from five completed prevalence surveys of Parkinson's disease (PD), we investigated case ascertainment uncertainties that potentially have a direct effect on prevalence. These uncertainties arise from the choice of diagnostic criteria, the choice of screening method, and the amount of information lost because of nonresponse. The surveys were conducted in Argentina, India, China, Italy, and the Netherlands. Our analyses consisted of simple comparisons of prevalence results, positive predictive values (a screening measure), and nonresponse percentages. We found that (a) prevalence comparisons between surveys have diminished value if the surveys used different diagnostic criteria for PD; (b) screening performance may be affected adversely if symptom questions are answered by one family member for the entire family living together rather than by each family member individually; and (c) nonresponse from refusal or unavailability does not necessarily lead to bias, but special caution may be appropriate with prevalence results pertaining to elderly women

Novelty seeking and introversion do not predict the long-term risk of Parkinson disease

OBJECTIVE: It has been suggested that people who develop Parkinson disease (PD) may have a characteristic premorbid personality. We tested this hypothesis using a large historical cohort study with long follow-up. METHODS: We conducted a historical cohort study in the region including the 120-mile radius centered in Rochester, MN. We recruited 7,216 subjects who completed the Minnesota Multiphasic Personality Inventory (MMPI) for research at the Mayo Clinic from 1962 through 1965 and we considered 5 MMPI scales to measure sensation seeking, hypomania, positive emotionality, social introversion, and constraint. A total of 6,822 subjects (94.5% of the baseline sample) were followed over 4 decades either actively (via interview and examination) or passively (via medical records). RESULTS: During follow-up, 227 subjects developed parkinsonism (156 developed PD). The 3 MMPI scales that we selected to measure the extroverted personality construct (sensation seeking, hypomania, and positive emotionality) did not show the expected pattern of higher scores associated with reduced risk of PD. Similarly, the 2 MMPI scales that we selected to measure the introverted personality construct (social introversion and constraint) did not show the expected pattern of higher scores associated with increased risk of PD. However, higher scores for constraint were associated with an increased risk of all types of parkinsonism pooled together (hazard ratio 1.39; 95% CI 1.06-1.84; p = 0.02). CONCLUSIONS: We suggest that personality traits related to introversion and extroversion do not predict the risk of PD. © 2010 by AAN Enterprises, Inc

A network of investigator networks in human genome epidemiology

The task of identifying genetic determinants for complex, multigenetic diseases is hampered by small studies, publication and reporting biases, and lack of common standards worldwide. The authors propose the creation of a network of networks that include groups of investigators collecting data for human genome epidemiology research. Twenty-three networks of investigators addressing specific diseases or research topics and representing several hundreds of teams have already joined this initiative. For each field, the authors are currently creating a core registry of teams already participating in the respective network. A wider international registry will include all other teams also working in the same field. Independent investigators are invited to join the registries and existing networks and to join forces in creating additional ones as needed. The network of networks aims to register these networks, teams, and investigators; be a resource for information about or connections to the many networks; offer methodological support; promote sound design and standardization of analytical practices; generate inclusive overviews of fields at large; facilitate rapid confirmation of findings; and avoid duplication of effort. Copyright \ua9 2005 by the Johns Hopkins Bloomberg School of Public Health All rights reserved