YKL-40 Level and Hypertension Incidence: A Population-Based Nested Case-Control Study in China

Background-Human cartilage glycoprotein-39 (YKL-40) has been suggested to be a new marker of inflammation, atherosclerosis, and endothelial dysfunction. However, whether a higher level of YKL-40 is an independent risk factor for hypertension incidence is still unknown. Methods and Results-In a nested case-control study within a prospective cohort of 12 423 initially healthy Chinese adults, we measured baseline plasma concentrations of YKL-40 among 700 new-onset hypertension cases and 700 age-and sex-matched controls. Multiple conditional logistic regression analyses were used to calculate the odds ratios (95% CIs) of hypertension associated with higher levels of YKL-40 both in the total population and in the age-(> 55 and <= 55 years) and sex-matched subgroups. Among the total population, YKL-40 levels were not associated with hypertension risk. In the subgroup older than 55 years, odds ratios (95% CIs) of hypertension for those in the two higher tertiles of YKL-40 were 1.23 (0.77-1.97) and 1.59 (0.99-2.55) (P for linear trend=0.05). In the male subgroup, odds ratios (95% CIs) of hypertension for those in the two higher tertiles of YKL-40 were 1.55 (0.88-2.72) and 2.09 (1.14-3.82) (P for linear trend=0.02). An interaction effect was observed between YKL-40 and sex (P for interaction < 0.01) but not between YKL-40 and age (P for interaction=0.21). High YKL-40 level significantly increased hypertension risk in men but decreased hypertension risk with a trend although not significant in women. Conclusions-This study suggests that YKL-40 is associated with hypertension incidence only among men. The study findings need to be further verified by prospective cohort studies or clinical trials.