The effect of point of reference on the association between self-rated health and mortality.
This study examines the effect of point of reference on the predictive validity of self-rated health for mortality in a 5-year follow-up period. Two self-rated health measures are examined: an age group comparative question and a global question with no explicit point of reference. The baseline data (SweOld) is a nationally representative interview survey among Swedish people aged 77+ in 1992. Mortality for the 1992-1996 period was analysed using Cox proportional hazards regression models. Age-referential self-rated health was found to be a better predictor of elderly men's mortality both in non-adjusted models and in models adjusting for age and both self-rated health measures. In separate analyses, both measures were found to be equally strong predictors of women's mortality. When adding both measures into the model simultaneously, the age-referential question lost much of its predictive power. The findings suggest that self-rated health measures are not insensitive to differences in question wording.
Manderbacka
Kristiina
K
National Research and Development Centre for Welfare and Health, Health Services Research, FIN-00531, Helsinki, Finland. kristina.manderbacka@stakes.fi
Kåreholt
Ingemar
I
Martikainen
Pekka
P
Lundberg
Olle
O
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D015577:Geriatric Assessment / Q000379:methods*; D006304:Health Status; D006801:Humans; D008297:Male; D009026:Mortality; D016016:Proportional Hazards Models; D018570:Risk Assessment / Q000379:methods; D012647:Self-Assessment; D011795:Surveys and Questionnaires / Q000592:standards*; D013548:Sweden / Q000453:epidemiology