The haptoglobin 2-2 genotype is associated with inflammation and carotid artery intima-media thickness

Abstract

The haptoglobin 2-2 genotype is associated with atherosclerosis in type 2 diabetes mellitus. We examined the associations of the haptoglobin 2-2 genotype with C-reactive protein (high-sensitivity C-reactive protein) and carotid artery intima-media thickness, adjusting for age, gender, ethnicity, type 2 diabetes mellitus, smoking status, body mass index, blood pressure, glycated haemoglobin, non-high-density lipoprotein cholesterol and medications via logistic multivariate regression in 200 subjects (160 type 2 diabetes mellitus versus 40 healthy individuals). The prevalence of the haptoglobin 2-2 genotype was 58% (115/200), higher in the Indians than in Chinese (72% versus 45%, p = 0.001). Multivariate analysis showed that the haptoglobin 2-2 genotype was associated with high-sensitivity C-reactive protein [mean: 3.5 ± 3.9 versus 2.2 ± 2.6 mg/L (non-haptoglobin 2-2), p < 0.001], haptoglobin concentration [mean: 116.9 ± 54.4.0 versus 147.2 ± 54.5 mg/dL (non-haptoglobin 2-2), p < 0.001] and average carotid artery intima-media thickness (multiplied by 10) [6.15 ± 1.22 versus 5.98 ± 1.20 mm (non-haptoglobin 2-2), p = 0.013]. This pilot study shows an association of the haptoglobin 2-2 genotype with low-grade inflammation, haptoglobin concentration and carotid artery intima-media thickness in multi-ethnic Singapore.