Association between greenspace and lung function in Italian children-adolescents

Few studies have examined the impact of urban greenspace exposure on lung function in children-adolescents, and the available evidence is still inconsistent. The aim of the current study was to verify the hypothesis that the effects of greenspace exposure vary with differing levels of lung function of children-adolescents.

Between November 2005 and May 2006, 2150 children-adolescents (age-range: 10-15 years) living in the city of Palermo were enrolled in a cross-sectional survey. Parents were interviewed through a modified version of the Italian Studies on Respiratory Disorders in Children and the Environment (SIDRIA) questionnaire. All children-adolescents performed spirometry and were tested for allergic sensitization. Exposures to greenspace and grey space at the home addresses were measured using the CORINE land-cover classes. Parametric quantile regression models were applied for assessing the association between greenspace exposure and spirometry parameters, accounting for possible confounders and effect modifiers. A p-value lower than 0.05 was considered statistically significant.

From the 1^st to the 21^st percentile, children-adolescents living within greenspace had higher FEV₁ than those living within grey space. In particular, the estimated effects were: 1^st (β = 0.238 L, p = 0.01), 5^th (β = 0.140 L, p = 0.01), 10^th (β = 0.097 L, p = 0.015), and 15^th (β = 0.073 L, p = 0.025). Similarly, from the 1st to the 29^th percentile, children-adolescents living within greenspace had higher FVC than those living within grey space. In particular, the estimated effects were: 1^st (β = 0.367 L, p = 0.0003), 5^th (β = 0.215 L, p = 0.0003), 10^th (β = 0.150 L, p = 0.0004), and 15^th (β = 0.112 L, p = 0.001). No significant associations were found for FEV₁/FVC, FEF_25-75 and FEF_25-75/FVC.

Quantile regression techniques may provide new insights into the evaluation of the association between greenspace exposure and lung function in children-adolescents, showing substantially heterogeneous effects from lower to higher quantiles of spirometry parameters. These results may help implementing policies for planning sustainable housing and surrounding greenspaces.