Polymorphism Ncol in tumor necrosis factor B is associated with fasting glycemia and lipid parameters in healthy non-obese caucasian subjects

BACKGROUND: The study was designed to investigate the associations among polymorphisms TNF-B Ncol and TNF-alpha -308G/A, plasma TNF-alpha levels and metabolic and anthropometric parameters related to insulin sensitivity in a set of 113 Caucasian subjects undergoing oral glucose tolerance test (oGTT). METHODS: Genotypes were detected by PCR; BMI, WHR, glycemia during oGTT, fasting immunoreactive insulin, fasting C-peptide, HbA(1c), total cholesterol, triglycerides, HDL, LDL and plasma TNF-alpha levels were measured in each subject. RESULTS: Type 2 diabetes was diagnosed in 10 subjects, impaired glucose tolerance (IGT) in 41, normal glucose tolerance (NGT) in 62. Significant differences among genotypes of the TNF-B Ncol were observed for FPG (P=0.0063), LDL (P=0.0179) and marginally for total cholesterol (P=0.0763) in NGT group. After the classification of NGT subjects into obese and non-obese according to BMI, associations of TNF-B Ncol with FPG, LDL and cholesterol were proved in non-obese subgroup only. TNF-alpha -308G/A polymorphism was not associated with any of the parameters studied. TNF-alpha levels did not revealed difference among NGT, IGT and DM groups or genotype-dependent differences. CONCLUSIONS: Our results indicate significant association of the TNF-B Ncol polymorphism with FPG, LDL and total cholesterol in normoglycemic non-obese Caucasian subjects. This polymorphism could be involved in genetic modulation of glucose and lipid homeostasis and regulation of insulin sensitivity already in healthy state. Disturbances of this regulation could be component of pathogenesis of type 2 diabetes mellitus.