Disentangling cultural issues in quality of life data

Objective: To describe a process for understanding ethnic differences in health-related quality of life (HRQL). Design: Analyses are based on the baseline data from the Study of Women's Health Across the Nation (SWAN), a multiethnic longitudinal study of women transitioning through menopause. There were a total of 3,302 women aged 42 to 52 entered into the cohort, which included white, African American, Hispanic, Chinese, and Japanese women enrolled at seven sites in the United States. Five domains from the Medical Outcomes Short Form Health Survey (SF-36) were used to measure HRQL. Acculturation was assessed by language of questionnaire completion. Covariates included socioeconomic status, sociodemographics, health, lifestyle, and social circumstances. Logistic regression was used to examine the relationship between acculturation and HRQL. Results: Previous unadjusted analyses found ethnic differences on all five domains of the SF-36. However, ethnic differences largely disappeared after adjusting for covariates. Remaining differences showed that less acculturated Hispanic women reported more bodily pain and more impaired social functioning than non-Hispanic white women. Less acculturated Japanese women were less likely to report problems on the role-emotional scale. Conclusions: The majority of ethnic differences in HRQL could be explained by covariates. These findings highlight the importance of controlling for differences in sample characteristics in any multiethnic study.