Air pollution exposure and bone mineral density in young children: results from the ENVIRONAGE birth cohort

Abstract

Previous epidemiological studies have suggested that air pollution exposure has an adverse effect on bone health in older individuals. However , no studies on early life exposure to air pollution and childhood bone mineral density have been reported. Therefore, this study aims to investigate whether long-term exposure to air pollution is associated with a change in bone mineral density in young children. Within the ongoing prospective birth cohort ENVIRONAGE (Envi-ronmental Influence on Ageing in Early Life), a total of 478 children aged 4-6 were followed-up. Radial bone mineral density (m/s) was assessed using a quantitative ultrasound method. The residential air pollution exposure (μg/m 3) one year before the follow-up was estimated using a high-resolution spatial-temporal interpolation method. Multiple linear regression models were used after adjusting for relevant covariates and potential confounders. Radial bone mineral density was on average (SD) 3680.84 (112.39) m/s. An interquartile (IQR) increment in long-term exposure to PM 2.5 (2.54 μg/m 3) and PM 10 (3.65 μg/m 3) was associated with a decrease of 24.81 m/s (95% CI:-42.55% to-7.07%, p=0.006) and 26.24 m/s (95% CI:-41.95% to 10.54%, p=0.001) in bone mineral density, respectively. On the other hand, no significant associations were observed for long-term exposure to nitrogen dioxide and black carbon. These findings provide evidence that long-term exposure to particulate matter has a relevant effect on childhood bone mineral density. Moreover, this study reinforces the need for increased public health policies and awareness campaigns on air quality improvement with long-term implications on bone health.