Association of lipoprotein(a) concentration with age in two ethnic groups (Kyrgyz and Slavs) in a population-based sample of residents of the Chui region of the Kyrgyz Republic

Objective: To perform a comparative analysis of lipoprotein(a) (Lp(a)) concentration in Kyrgyz and Slavic ethnic groups and to assess its association with age, adjusted for sex. Methods: This cross-sectional study included 1161 residents of the Chui Region of the Kyrgyz Republic: 714 Kyrgyz and 447 Slavs. The mean age of participants was 41.2 (13.1) years; men accounted for 40.8% of the sample. Lp(a) concentration was measured using an ARCHITECT c4000 automated analyzer (Abbott). Because of the skewed distribution of Lp(a), data are presented as median and interquartile range. Between-group differences were assessed with the Mann–Whitney U test. The association of Lp(a) with age was examined using Spearman correlation analysis and linear regression analysis. Results: The median Lp(a) concentration in the total sample was 6.2 mg/dL; a level >30 mg/dL was found in 9.3% of participants. Lp(a) concentration did not differ significantly between Kyrgyz and Slavs: 6.2 (2.9; 12.7) vs 6.5 (2.9; 16.1) mg/dL, respectively (p=0.117). A positive but weak correlation of Lp(a) with age was found in Kyrgyz (r s =0.148; p=0.002) and Slavs (r s =0.173; p<0.001). Among Kyrgyz, the association persisted in both men (r s =0.138; p=0.015) and women (r s =0.105; p=0.035). In Slavs, the association was present in women (r s =0.227; p<0.001) but absent in men (r s =0.098; p=0.206). The linear regression coefficient in Slavic women was higher than in Kyrgyz women (0.285 vs 0.100 mg/dL per year; p=0.033). Conclusion: Lp(a) concentration did not differ between the ethnic groups studied. The observed age-related associations were weak and heterogeneous with respect to sex and ethnicity. The cross-sectional design does not allow these findings to be interpreted as an intra-individual increase in Lp(a) with age.