Occurrence of metabolic syndrome in young adults and inequalities according to sex, skin color, and socioeconomic status: evidence from two birth cohorts in Southern Brazil

The aim of the present study was to identify the prevalence of metabolic syndrome at 22 and 30 years of age, determine inequalities by sex, skin color, and socioeconomic status, and investigate the intersections of these variables. A cross-sectional analysis was conducted using data from the 1993 (22 years of age) and 1982 (22 and 30 years of age) Pelotas (Brazil) birth cohort. Metabolic syndrome was defined based on the criteria of the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) and the International Diabetes Federation (IDF). Inequalities in terms of sex, skin color, and socioeconomic status were described in Equiplots and analyzed by absolute measures (prevalence ratio and slope index of inequality - SII]) and relative measures (difference in prevalence and concentration index - CIX]). At 22 years of age, the prevalence of metabolic syndrome was 18.2% (IDF) and 13.5% (NCEP-ATP III) in the 1993 cohort, and 11.3% (IDF) and 8.6% (NCEP-ATP III) in the 1982 cohort. At 30 years of age (1982 cohort), the prevalence was 15.5% (IDF) and 10.7% (NCEP-ATP III). The greatest inequality in terms of socioeconomic status occurred in the 1982 cohort at 22 years of age based on the NCEP-ATP III criteria among women (SII: -8.7p.p. [95%CI: -13.2; -4.2]; CIX: -20.1% [95%CI: -29.7; -10.5]) and men (SII: 6.5p.p. [95%CI: 0.1; 12.9]; CIX: 7.9% [95%CI: 0.6; 15.3]). The most affected subgroups were White women with a lower socioeconomic status and Black/Mixed-race men (1993 cohort) and White men (1982 cohort) with a higher socioesconomic status. Our results demonstrate that metabolic syndrome is not evenly distributed in this population and that its occurrence may be influenced by intersections between socioeconomic status, sex, and skin color.