Association of air pollution and hematologic parameters in children and adolescents

To assess the relationship between air pollution and hematologic parameters in a population-based sample of children and adolescents.

This cross-sectional study was conducted in 2009-2010 among school students randomly selected from different areas of Isfahan city, the second largest and most air-polluted city in Iran. The association of air pollutant levels with hemoglobin, platelets, red and white blood cells (RBC and WBC, respectively) was determined by multiple linear and logistic regression analyses, after adjustment for age, gender, anthropometric measures, meteorological factors, and dietary and physical activity habits.

The study participants consisted of 134 students (48.5% boys) with a mean age of 13.10±2.21 years. While the mean Pollutant Standards Index (PSI) was at moderate level, the mean particulate matter ≤ 10 µm (PM10) was more than twice the normal level. Multiple linear regression analysis showed that PSI and most air pollutants, notably PM10, had significant negative relationship with hemoglobin and RBC count, and positive significant relationship with WBC and platelet counts. The odds ratio of elevated WBC increased as the quartiles of PM10, ozone and PSI increased, however these associations reached significant level only in the highest quartile of PM10 and PSI. The corresponding figures for hemoglobin and RBC were in opposite direction.

The association of air pollutants with hematologic parameters and a possible pro-inflammatory state is highlighted. The presence of these associations with PM10 in a moderate mean PSI level underscores the necessity to re-examine environmental health policies for the pediatric age group.