Assessment of the quality of the childhood physical abuse measure in the National Population Health Survey

Background: The long-term health consequences of childhood physical abuse are often studied using retrospective self-reports collected from adults. This study assesses the quality of a question on childhood physical abuse in the National Population Health Survey (NPHS). Data and methods: All NPHS respondents aged 18 or older (n = 15,027) were asked a question about childhood physical abuse in cycles 1 (1994/1995), 7 (2006/2007) and 8 (2008/2009). The reliability of this question was assessed over these periods. Associations between response patterns to the abuse item and health conditions that are related to childhood physical abuse were examined. Results: Across all NPHS cycles, very few respondents refused to answer or replied "don't know" to the item on childhood physical abuse. Reliability, as measured by Cohen's kappa statistic, was "substantial" for the two-year interval between cycles 7 and 8, and "moderate" for the 12- and 14-year intervals from cycle 1. Kappa estimates were similar when examined by various demographic factors. Compared with consistent deniers, respondents who consistently affirmed childhood physical abuse and those who provided inconsistent responses had increased odds of depression, fair or poor self-perceived health, disability, migraine, and heart disease. Interpretation: Despite some limitations, the NPHS question on childhood physical abuse allows researchers to investigate long-term health consequences of abuse.