Air pollution and serum C-reactive protein concentration in children

BACKGROUND: Few biological markers that allow evaluation of the effects of air pollution on human health have been identified. This study evaluated the association of serum C-reactive protein (CRP) concentration in children with their respiratory symptoms and air pollution. METHODS: Respiratory symptoms and serum concentrations of CRP were examined in 2,094 school children living in 3 communities with different concentrations of air pollutants in Chiba Prefecture, Japan in 2001. The relationships between serum CRP concentration and sex, age, respiratory symptoms, and various environmental factors were analyzed. RESULTS: Serum CRP concentration decreased with age, and was significantly higher both in children who were bottle-fed in infancy and whose mothers smoked. Children with wheeze had significantly higher serum CRP concentration than those without wheeze. After adjustment for potential confounding factors, increased serum CRP concentrations of the 90th percentile (1.4 mg/L) or above were significantly associated with atmospheric concentration of suspended particulate matter (SPM) (odds ratio [OR] =1.49 for the range of observed concentrations, 95% confidence interval [CI]: 1.07-2.06) and sulfur dioxide (SO2) (OR = 1.45, 95% CI: 1.04-2.03). In a two-pollutant model including SPM and nitrogen dioxide (NO2) concentrations, increased serum CRP concentrations were also associated with SPM (OR = 1.94, 95% CI: 1.08-3.50), but no such association was found with NO2 (OR = 0.62, 95% CI: 0.26-1.48). CONCLUSION: Serum CRP concentration is related to wheezing and the degree of air pollution. Because the concentrations of air pollutants are highly correlated, it is difficult to elaborate on which pollutant has a stronger effect on serum CRP concentrations.