Background and objective: The SF-36 Health Survey questionnaire is the most widely used instrument to measure health-related quality of life. Reference measures are needed to interpret its results in clinical and population studies. In 1996, a study provided population-based norms for Spain, but these were not disaggregated by age in subjects aged 75 years and over, even though health status changes with aging among those who overpass such age. Moreover, health status in elderly people from developed countries has improved over the last years. This study obtains population-based norms for the Spanish version of the SF-36 Health Survey in five-year age-groups for those aged 60 to 85 and over.
Subjects and method: Cross-sectional survey on a sample of 3,949 non-institutionalised subjects representative of the Spanish population aged 60 years and over. Information on the SF-36 Health Survey was obtained through house-hold personal interviews. Central position and dispersion statistics, as well as percentiles, were calculated for each of the eight SF-36 scales by age and sex. Cronbach's alpha coefficients were calculated to assess the internal reliability of each scale.
Results: Subjects reported higher scores for emotional role (mean [SD] 84.8 [32.9]), social functioning (79.2 [28.0]) and physical role (73.3 [41.1]). For all scales, mean scores were higher (better perceived health) among men than women (p < 0.0001). As age increased, mean scores in all scales decreased (p for linear trend < 0.001) except for mental health (p for linear trend = 0.29 in women, p for lineal trend = 0.14 in men), yet the decrease was greater for physical functioning and physical role. Reliability was very high for all scales (Cronbach's alpha from 0.84 to 0.95). RESULTS were similar to those of the study carried out in 1996.
Conclusions: These results extend those obtained in 1996 and facilitate the interpretation of the SF-36 Health Survey values in clinical and population studies in the Spanish population aged 60 years and older.