Exposure to air pollution, noise and green space may be associated with children’s body mass index. However, no studies have examined the combined effects of these environmental exposures on markers of adiposity in children. We investigated the individual and combined associations of air pollution, road traffic noise and green space with overweight in children aged 12 years.Methods
Weight and height were measured at age 12 years in 1508 participants of the Dutch PIAMA birth cohort study. Annual average air pollution levels (NO2, PM2.5, PM10, PMcoarse, and PM2.5 absorbance) at the children’s homes were estimated by land-use regression models. Road traffic noise exposure was assessed by linking children’s home addresses to modelled road traffic noise levels. We used different indicators to assess exposure to green space: the average Normalised Difference Vegetation Index (NDVI) and percentages of urban, agricultural and natural green space in buffers of 300 m and 3000 m around the children’s homes, and the distance from the homes to the nearest park. We analysed the associations between the exposures and overweight by logistic regression.Results
Twelve percent of the children were overweight. Neither in single- nor in multi-exposure models we found significant associations of air pollution, road traffic noise, and green space with overweight. For example, we found an OR per interquartile range increase in exposure of 1.12 [95% CI: 0.90 to 1.39] for NO2, OR 1.03 [95% CI: 0.84 to 1.26] for PM2.5 absorbance, OR 1.15 [95% CI: 0.94 to 1.40] for road traffic noise and OR 0.85 [95% CI: 0.68 to 1.05] and OR 0.87 [95% CI: 0.71 to 1.06] for the average NDVI in the 300 m and 3000 m buffer, respectively, in single-exposure models. The associations changed only slightly when the other environmental exposures were added in multi-exposure models.Conclusion
Our results do not provide support for adverse effects of air pollution and road traffic noise or beneficial effects of green space exposure on overweight in children aged 12 years. We will perform longitudinal analyses to examine the associations of air pollution, road traffic noise and green space with overweight throughout childhood.