[Spousal correlations of blood lipid based on a family design]

To explore the spousal correlations of total cholesterol (TC), total triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C), and to investigate the reasons behind these spousal correlations.

Participants and data were from the baseline survey of family-based cohort studies in Fangshan, Beijing and Tulou, Fujian. The origin of spousal correlations were explored from perspectives of convergence, assortative mating, social homogamy. Pearson ' s correlation and generalized linear models (GLM) were used to estimate the spousal correlation. Convergence was assessed by Pearson ' s correlation between the phenotypic differences between couples and the duration of marriage, with GLM used for further validation. Pearson ' s correlation of genetic risk scores (GRS) and couple-specific Mendelian randomization (MR) were calculated to assess the genetic correlation and possible causal relationships between spouses. Two-independent-sample t-tests were used to compare GRS consistency across subgroups divided by education attainment, couple-specific MR and Q statistics used to test assortative mating in subgroups and intergroup differences.

In the study, 342 couples (287 couples from Fangshan and 55 couples from Fujian) were included, with the average age of (64.91±8.76) years. Spousal correlations of TC, TG, HDL-C, and LDL-C showed statistically significant associations both before and after adjusting for covariates, with effect sizes of 0.229 (95%CI: 0.125-0.327), 0.257 (95%CI: 0.155-0.354), 0.179 (95%CI: 0.074-0.280), and 0.181 (95%CI: 0.076-0.282). For convergence, for each additional year of marriage, ΔTC increased by 0.016 mmol/L (95%CI: 0.001-0.033 mmol/L), and ΔLDL-C increased by 0.017 mmol/L (95%CI: 0.002-0.031 mmol/L). For assortative mating, GRS correlations and results of couple specific MR didn ' t show any statistical significance. For social homogamy, no differences in GRS or assortative mating were found between subgroups stratified by education attainment.

The blood lipid in participants exhibit spousal phenotypic correlations, however, no effects of convergence, assortative mating or social homogamy were observed. More independent studies with larger sample sizes are warranted to further validate these findings in the future.