Sex-related Association of Serum Uric Acid and Carotid Atherosclerosis in a Hypertensive Nigerian Population

Background: Atherosclerosis is a primary cause of cardiovascular morbidity and mortality. Dyslipidemia is a key risk factor for the development of atherosclerosis. Carotid intima-media thickness (CIMT) is an established tool for the detection and assessment of progression of atherosclerosis. Serum uric acid (SUA) a product of purine metabolism has been recognized as a marker of endothelial dysfunction. The aim of this study was to determine the effect of gender difference in serum uric acid on subclinical carotid atherosclerosis as determined by CIMT in hypertensive patients attending the cardiology clinic of the UPTH.

Methods: 144 Hypertensive subjects and 72 age- and sex- matched controls were recruited. Their waist circumference, body mass indices and fasting lipid profile and SUA were determined. Diabetics and patients receiving uric acid-lowering drugs were excluded. CIMT was measured in all study subjects using standard protocol. Results were subjected to linear, multiple, and logistic regression analyses.

Results: Eighty-seven (61.7%) of the cases had hyperuricemia while it was present in 29(39.7%) of the controls (p=0.002). The mean uric acid was significantly higher among the cases when compared to the control group (382.8 ±109.2 µmol/l versus 347.8 ±97.4 µmol/l, p=0.021). The male subjects had a higher SUA levels than the female subjects (415.1± 98.53 µmol/l versus 334.7± 98.50 µmol/l, p<0.001). The mean CIMT of the hypertensive subjects was significantly higher than that of the control cohorts (0.79± 0.19 mm versus 0.62± 0.78 mm, p<0.001). Binary logistic regression analysis of the whole population after adjusting for age, sex, waist circumference, SBP, TG, revealed that the association between SUA and carotid atherosclerosis was significant in men but not in women.

Conclusion: A significantly positive association between SUA level and CIMT was observed in the present sample of hypertensive Nigerian adult population. This association was evident in men with essential hypertension, but not in the women.