Exposure to urban air pollution and bone health in clinically healthy six-year-old-children

Air pollution induces systemic infl ammation, as well as respiratory, myocardial and brain infl ammation in children. Peak bone mass is infl uenced by environmental factors. We tested the hypothesis that six-yearolds with lifetime exposures to urban air pollution will have alterations in infl ammatory markers and bone mineral density (BMD) as opposed to low-polluted city residents when matched for BMI, breast feeding history, skin phototype, age, sex and socioeconomic status. This pilot study included 20 children from Mexico City (MC) (6.17 years ± 0.63 years) and 15 controls (6.27 years ± 0.76 years). We performed full paediatric examinations, a history of outdoor exposures, seven-day dietary recalls, serum infl ammatory markers and dual-energy X-ray absorptiometry (DXA). Children in MC had signifi cantly higher concentrations of IL-6 (p=0.001), marked reductions in total blood neutrophils (p= 0.0002) and an increase in monocytes (p=0.005). MC children also had an insuffi cient Vitamin D intake and spent less time outdoors than controls (p<0.001) in an environment characterized by decreased UV light, with ozone and fi ne particulates concentrations above standard values. There were no signifi cant differences between the cohorts in DXA Z scores. The impact of systemic infl ammation, vitamin D insuffi ciency, air pollution, urban violence and poverty may have long-term bone detrimental outcomes in exposed paediatric populations as they grow older, increasing the risk of low bone mass and osteoporosis. The selection of reference populations for DXA must take into account air pollution exposures.