Validity and reliability of adult recall of past sun exposure in a case-control study of multiple sclerosis

Abstract

Background: Measurement of past sun exposure through recall by adults has the potential for measurement error. We aimed to investigate aspects of validity and reliability of self-reported past sun exposure. Methods: A population-based case-control study was conducted in Tasmania on 136 cases with multiple sclerosis and 272 age- and sex-matched community controls. Repeat interviews on 52 cases and 52 controls were done on average 11 weeks after the initial interview. Sun exposure was assessed by questionnaire and lifetime calendar. Other measurements included serum 25-hydroxyvitamin D, actinic damage, and skin phenotype. Results: There was an association between recent sun exposure and serum ..