IL-18: relationship with anthropometry, body composition parameters, leptin and arterial hypertension

Interleukin-18 (IL-18) is a potent pro-inflammatory cytokine with potential atherogenic properties whose role in human obesity has been recently suggested. The aim of our study was to analyze the physiologic distribution of IL-18 among sexes and all decades of the adult life in a healthy population randomly selected and to study its relationship with anthropometric, body composition measurements and leptin concentrations. We also studied the relationship of IL-18 with smoking and arterial hypertension, known risk factors implicated in atherogenesis.

One hundred and thirty four men and 127 healthy women were included in the study. Plasma concentrations of IL-18 and leptin were determined in all subjects. Body composition was evaluated by bioelectrical impedanciometry.

IL-18 was distributed similarly in men and women and throughout decades. No significant differences were found in IL-18 between obese and normal-weight men and women according to their body mass index and body fat content. Higher IL-18 concentrations were found in subjects with arterial hypertension. In the bivariate correlation analysis only waist to hip ratio correlated weakly with IL-18 in the whole population (r=0.12, p=0.04). In the multiple regression analysis the relationship between IL-18 and waist to hip ratio lost significance after adjusting for age, sex and body mass index. However, IL-18 remained associated with arterial hypertension (adjusted r2=0.25, p=0.023).

The lack of correlation between IL-18 with anthropometric, body composition variables and leptin in our healthy population argues against a role of this cytokine in obesity. Moreover, our findings suggest the implication of this interleukin in the atherogenic process induced by arterial hypertension.