title: Panel studies of air pollution in patients with COPD: Systematic review and meta-analysis.
abstract: BACKGROUND
  Epidemiological studies have shown an increase in morbidity and mortality rates in patients with chronic obstructive pulmonary disease (COPD) following exposure to elevated levels of air pollution. Panel studies have been used to assess short-term effects of air pollution which are not detected by registry studies, specifically lung function and symptoms. The aim of this systematic review was to assess the evidence of panel studies on acute effects of air pollution among patients with COPD.
  
  
  METHODS
  We searched the PubMed database, and identified additional studies by inspecting reference lists and literature reviews. We identified and summarized 25 panel studies that were published between 1993 and February 2016. Results were presented in forest plots and effect estimates of sufficiently comparable outcomes and pollutants were summarized by a random-effects meta-analysis.
  
  
  RESULTS
  Meta-analysis showed that a 10µg/m3increase in ambient levels of particles less than 10µm in diameter (PM10) had a small, but statistically significant impact on FEV1(-3.38mL, 95% CI -6.39 to -0.37) and PEF (-0.61L/min, -1.20 to -0.01). There was significant heterogeneity across the included studies. A forest plot showing associations between PM10and respiratory symptoms was also suggestive of an adverse effect of particulate air pollution, but this was not formally tested in a meta-analysis due to the heterogeneity of outcomes. Results for gaseous pollutants were inconsistent for lung function or symptoms.
  
  
  CONCLUSIONS
  Evidence from the identified panel studies indicated statistically significant associations of particulate matter air pollution with lung function in patients with COPD.
authors: Division Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
authors: Lizan D
authors: LD
authors: Bloemsma
authors: Division Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
authors: Gerard
authors: G
authors: Hoek
authors: Division Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands. Electronic address: L.A.Smit@uu.nl.
authors: Lidwien A M
authors: LAM
authors: Smit
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity; D000397:Air Pollution / Q000009:adverse effects*; D006801:Humans; D029424:Pulmonary Disease, Chronic Obstructive
chemical_list: D000393:Air Pollutants
keywords: Air pollution; COPD; Panel studies