A paraoxonase gene polymorphism, PON 1 (55), as an independent risk factor for increased carotid intima-media thickness in middle-aged women

Paraoxonase (PON) gene polymorphisms have been proposed as genetic markers of risk for cardiovascular disease (CVD). Sporadic results suggest they are correlated with intima-media thickness (IMT), an indicator of preclinical atherosclerotic disease. We have investigated whether polymorphisms PON 1 (M/L) 55, (Q/R) 192, PON 2 (S/C) 311 are related to site-specific carotid plaques in 310 middle-aged women. Subjects were also investigated for physical and biochemical parameters including oxidative markers to evaluate their effect on development of atherosclerotic plaques (IMT>1.2 mm) identified by high resolution B-mode ultrasound. We demonstrate that PON 1 (LL+ML) 55 is associated with plaques both at the bifurcation (OR=2.40; 95% CI 1.00–5.90) and at the common carotid artery (OR=2.75; 95% CI 1.01–7.50), and to the total number of plaques at any site (P<0.05). This polymorphism is an independent parameter with respect to other variables that are significantly associated with plaques, i.e. systolic blood pressure (OR=2.06; 95% CI 1.11–3.81) and oxidized low-density lipoprotein (LDL) antibodies (OR=1.96; 95% CI 1.05–3.69) in cases of common carotid plaques, and lipid peroxides (OR=1.86; 95% CI 1.00–3.50) in cases of bifurcation plaques. In conclusion, PON 1 (LL+ML) 55 but not PON 1 (Q/R) 192 or PON 2 (S/C) 311, appears to be an independent risk factor for increased carotid IMT in middle-aged women.