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 vitamin D (time in the sun: r = 0.22, P < 0.01; activities outside: r = 0.31, P < 0.01 for controls) and between lifetime sun exposure and actinic damage [correlation between 0.34 (P < 0.01) and 0.17 (P = 0.01) for controls]. The test-retest weighted κ statistic of self-reported sun exposure ranged from 0.43 to 0.74. Recall of childhood/adolescent sun exposure by standardized questioning was no less reproducible than recall of recent adult sun exposure and no less reliable when made with the calendar method. Comparing the questionnaire and calendar method, the measures of childhood/adolescent sun exposure had a similar predictive validity for multiple sclerosis. Conclusions: The results of this study provide further evidence that adults are able to recall past sun exposure with shown validity and reliability and present information about the possible reasons for the good reliability of recalled sun exposure measures. Copyright © 2006 American Association for Cancer Research.

Item Type:	Refereed Article
Research Division:	Health Sciences
Research Group:	Epidemiology
Research Field:	Epidemiology not elsewhere classified
Objective Division:	Health
Objective Group:	Clinical health
Objective Field:	Clinical health not elsewhere classified
UTAS Author:	Van der Mei, IAF (Professor Ingrid van der Mei)
UTAS Author:	Blizzard, CL (Professor Leigh Blizzard)
ID Code:	39894
Year Published:	2006
Web of Science® Times Cited:	88
Deposited By:	Menzies Institute for Medical Research
Deposited On:	2006-08-01
Last Modified:	2009-09-10
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