Association of the Lipoprotein Lipase Gene T+495G Polymorphism With Central Obesity and Serum Lipids in a Twin Study

Abstract

The lipoprotein lipase (LPL) gene polymorphism is possibly involved in the pathophysiology of central obesity and dyslipidemia. The aim of this study was to investigate the association of LPL gene T+495G polymorphism with central obesity and serum lipids. A total of 961 adult twin pairs were enrolled from the program of Chinese Twin Registry, between 2001 and 2002. We used 90 cm of waist circumference in male and 80 cm in female as cut-off values of central obesity. The LPL gene T+495G polymorphism was analyzed with the use of genomic polymerase chain reaction and HindIII-restriction fragment length polymorphism. Two statistical methods were performed to test the effect of T+495G polymorphism of LPL gene on the relation between central obesity and lipid levels: one was the generalized estimating equation model for all twin pairs and the other was co-twin matched case-control analysis in 82 central obesity discordant monozygotic twin pairs. In male twins, central obesity was significantly associated with serum lipids except for high-density lipoprotein (HDL). In female twins, obesity twins had significantly higher levels of triglyceride (TG) and TG/HDL than nonobesity twins. There was no significant association between T+495G polymorphism and lipid levels for all twins, although +495G allele carrier was related with 6.7% decrease of TG was observed only in female twins. The interactions of T+495G polymorphism and central obesity were not found for TG, HDL, and TG/HDL. In central obesity discordant monozygotic twin pairs, central obesity was significantly related with 24.2%, 26.1%, and 4.1% increase of TG ,TG/HDL, and TC, respectively, in +495T/T genotype. These results suggest no association and interaction of T+495G polymorphism with central obesity and serum lipids for all twin pairs. Meanwhile, a modest genetic-environmental effect of T+495G polymorphism and central obesity was found in discordant monozygotic twin pairs. Therefore, the +495T/T genotype may be an independent risk factor associated with central obesity and lipids level. However, the role of LPL gene T+195G polymorphism in central obesity and dyslipidemia is complex and remains controversial. This hypothesis needs further investigation.