title: Relative and combined effects of socioeconomic status and diabetes on mortality: A nationwide cohort study.
abstract: Both low socioeconomic status (SES) and diabetes mellitus (DM) are important risk factors for mortality. However, little is known about their combined effects and relative contribution to the mortality risk.From a nationwide cohort provided by the National Health Insurance Service in Korea, 153,075 subjects who were over 30 years of age from 2003 to 2004 were followed-up until 2010. The SESs of the subjects in the DM and non-DM (NDM) groups were categorized into 3 groups (highest 30% as S1, middle 40% as S2, and lowest 30% as S3) based on the subjects' income levels.During the 7.9-year follow-up, 3933 deaths occurred. When the subjects were stratified into 6 groups by their socioeconomic and diabetes status, a linearly increasing pattern of the hazard ratio (HR) of mortality from the higher SES without diabetes group (NDM-S1, as a reference) to the lower SES with diabetes group (DM-S3; HR, 2.04, 95% confidence interval (CI), 1.80-2.36) was observed (P for trend < 0.001). Notably, subjects with DM in the highest SES group (DM-S1) had a significantly higher mortality risk than did non-DM subjects in the lowest SES group (NDM-S3). This pattern was maintained in cause-specific mortality but was more prominent in cardiovascular disease (CVD) and less prominent in cancer mortality. The association was not affected by gender; however, in individuals <60 years of age, the combined effects of SES and DM on mortality were more prominent (DM-S3; HR, 3.68, 95% CI, 2.95-4.60) than in those ≥60 years of age.Low SES and DM were major determinants of mortality and synergistically increased the risks of all-cause, CVD, and cancer mortality.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Korea University College of Medicine Department of Statistics, Korea University, Seoul, Korea.
authors.forename: Nam Hoon
authors.initials: NH
authors.lastname: Kim
authors.forename: Tae Joon
authors.initials: TJ
authors.lastname: Kim
authors.forename: Nan Hee
authors.initials: NH
authors.lastname: Kim
authors.forename: Kyung Mook
authors.initials: KM
authors.lastname: Choi
authors.forename: Sei Hyun
authors.initials: SH
authors.lastname: Baik
authors.forename: Dong Seop
authors.initials: DS
authors.lastname: Choi
authors.forename: Yousung
authors.initials: Y
authors.lastname: Park
authors.forename: Sin Gon
authors.initials: SG
authors.lastname: Kim
mesh_terms: D000328:Adult; D002318:Cardiovascular Diseases / Q000401:mortality; D002423:Cause of Death; D015331:Cohort Studies; D003920:Diabetes Mellitus / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000401:mortality; D016016:Proportional Hazards Models; D056910:Republic of Korea; D012306:Risk; D012307:Risk Factors; D012959:Socioeconomic Factors; D013223:Statistics as Topic