Comparability of surrogate and self-reported information on melanoma risk factors

Abstract

1987 and reported to the Queensland Cancer Registry. Of 6,404 cases for whom we were able to obtain a contract address and the doctor's agreement, 1,924 index subjects were selected from 5,475 (85%) who responded to a brief one-page questionnaire about family history of melanoma.The index subjects, here referred to as probands, comprised all cases who reported one or more first degree relatives with melanoma, and an equal sized random sample of cases who reported no first degree relatives with melanoma. Data collection Surrogate reports by probands about relatives A questionnaire was mailed to the probands, asking for information about standard melanoma risk factors for themselves and for their first degree relatives (parents, siblings, and children); the names and addresses of these relatives; and whether any relatives had had a melanoma diagnosed by a doctor. An abbreviated version of the risk factor questionnaire, asking about the same items but without cross-reporting on family members, was then mailed to the probands' living first degree relatives aged between 18 and 75 years. The standard risk factors studied were pigmentary traits (hair colour at age 21, and skin colour); sensitivity of the skin to the sun (average propensity to burn, ability to suntan, and tendency to acute sunburn); the number of episodes of painful sunburn; and a qualitative rating of the number of moles on the body (none, few, a moderate number, and very many moles, as represented in four graphical illustrations (Dubin et al., 1986)). Questions were asked with identical wording in both versions of the risk factor questionnaire, except that a 'Don't know' category was included in most questions in which cross-reporting was required (see Appendix).One thousand, two hundred and fifty-nine (65%) probands returned the cross-reporting questionnaire, of whom 1,242 named one or more first degree relatives. In many instances the same person was mentioned by more than one proband, and a total of 9,078 reported relatives comprised 8,992 individuals. The questionnaire without cross-reporting was

Early-life sun exposure and risk of melanoma before age 40 years

“…The much lower reporting of childhood sunburns by parents could suggest that parents' recall of sunburns is less accurate than their children's recall, and the observed strong association of parentrecalled sunburn with melanoma is due to recall bias. A previous Australian study also found low agreement between self-and surrogate reports of sunburn [30]. Published pooled risk estimates for the association of melanoma with sunburn range from 1.2 to 2.0 and are generally only slightly higher for sunburns during childhood than in adulthood [15,31,32].…”

Melanocortin-1 Receptor Polymorphisms and Risk of Melanoma: Is the Association Explained Solely by Pigmentation Phenotype?

“…Of a total of 7,619 living relatives, 5,158 (68%) responded after intensive telephone follow-up. Index patients and other family members provided proxy reports (the quality of which we have previously reported [Aitken et al 1993]) for an additional 4,588 relatives, providing a total of 9,746 relatives with risk-factor information. Only medically verified cases among relatives were included in the analysis.…”

“…Because the frequencies of the different MC1R variants do vary according to skin color, even when there is control for other confounders, we believe that this argues against the possibility that this effect is mediated solely by reporting bias. This explanation is made less likely by evidence relating subjective reports of skin color to objective measurements of skin reflectance and to independent clinical ratings (Green and Martin 1990;Aitken et al 1993). Otherwise, one might suggest that light-skinned individuals who have more exposure to the sun might tend to report a darker skin color and might have more melanoma.…”

Measurement of Ultraviolet Exposure in Epidemiological Studies of Skin and Skin Cancers

“…In another case–control study out of Australia, questionnaires regarding sun exposure were given to patients with melanoma and to controls, as well as to family members and friends (41). While the correlation is somewhat lower, the results were surprisingly similar to those described previously in which adult respondents were given two questionnaires separated by a few years.…”

“…The number of painful sunburns did not correlate as well, which seems logical as the memory of pain is likely much stronger in the memory of the patient than in that of his family members or friends. While the correlation between family members’ responses and that of the patients is somewhat lower than that provided by patients alone, the use of surrogate responses seems to provide a fairly reliable method for assessing a patient’s sun exposure (41).…”