Lipoprotein lipase gene S447X polymorphism modulates the relation between central obesity and serum lipids, a twin study

Objective: To investigate the impact of lipoprotein lipase (LPL) gene S447X polymorphism on the relation between central obesity and lipid levels. Design: A total of 961 adult twin pairs were included from the program of Chinese Twin Registry, between 2001 and 2002. Central obesity was defined as waist circumference >= 90cm for male and >= 80cm for female. Two statistical methods were performed to test the modification effect of S447X polymorphism of LPL gene on the relation between central obesity and lipid levels: one was Generalized Estimating Equation (GEE) models for all twin pairs and the other was co-twin matched case - control analysis in 82 central obesity discordant monozygotic twin pairs. Results: In GEE models for all twins, central obesity was significantly associated with serum lipids except for high-density lipoprotein (HDL), while X447 allele had favorable effects on the levels of triglyceride (TG), HDL and TG to HDL ratio (TG/HDL). The interactions of S447X polymorphism and central obesity were statistically significant for TG/HDL and HDL. In central obesity discordant monozygotic twin pairs, central obesity was significantly related with 26.2% increase of TG and 27.2% increase of TG/HDL in S/S447 genotype, while in 447X allele carrier, central obesity was significantly related with 13.7% increase of HDL. Conclusion: These results suggest that LPL gene S447X polymorphism modifies the relation between central obesity and serum lipids, which also stresses the importance of reducing waist circumference to improve serum lipids for people with central obesity, especially those with S/S447 genotype.