American journal of epidemiology
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In this nationwide population-based cohort study using national Danish registries, in the period 1980-2008, our aim was to study employment and receipt of disability pension after central nervous system infections. All patients diagnosed between 20 and 55 years of age with meningococcal (n = 451), pneumococcal (n = 553), or viral (n = 1,433) meningitis or with herpes simplex encephalitis (n = 115), who were alive 1 year after diagnosis, were identified. Comparison cohorts were drawn from the general population, and their members were individually matched on age and sex to patients. ⋯ The differences in probability of being employed or receiving disability pension in former meningococcal or viral meningitis patients versus members of the comparison cohorts were small. In conclusion, pneumococcal meningitis and herpes simplex encephalitis were associated with substantially decreased employment and increased need for disability pension. These associations did not seem to apply to meningococcal meningitis or viral meningitis.
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Clinical Trial
Measurement error of self-reported physical activity levels in New York City: assessment and correction.
Because it is difficult to objectively measure population-level physical activity levels, self-reported measures have been used as a surveillance tool. However, little is known about their validity in populations living in dense urban areas. We aimed to assess the validity of self-reported physical activity data against accelerometer-based measurements among adults living in New York City and to apply a practical tool to adjust for measurement error in complex sample data using a regression calibration method. ⋯ Two self-reported health measures (obesity and diabetes) were included as outcomes. Participants with higher accelerometer values were more likely to underreport the actual levels. (Accelerometer values were considered to be the reference values.) After correcting for measurement errors, we found that associations between outcomes and physical activity levels were substantially deattenuated. Despite difficulties in accurately monitoring physical activity levels in dense urban areas using self-reported data, our findings show the importance of performing a well-designed validation study because it allows for understanding and correcting measurement errors.