Table 5

Back-extrapolated from ESCAPE-period exposures (2008–11) to early 1990s ‘historic exposure estimates’: fixed-effect meta-analysis on cross-sectional results from SALIA (1985–1994), SAPALDIA (1991): all participants (upper section) and never-smokers (lower section), main model 3.

All participantsBack-extrapolated NO2, 10 µg/m3Back-extrapolated PM10, 10 µg/m3
Chronic bronchitisChronic coughChronic bronchitisChronic cough
OR95% CIOR95% CIOR95% CIOR95% CI
Cohort (year)
 SALIA (1985–94)1.08(0.96 to 1.21)1.08(0.98 to 1.20)1.04(0.85 to 1.29)1.10(0.92 to 1.33)
 SAPALDIA (1991)1.17(0.96 to 1.44)1.17(0.96 to 1.42)1.19(0.49 to 2.91)1.16(0.48 to 2.79)
 Overall effect1.10(1.00 to 1.22)1.10(1.01 to 1.20)1.05(0.86 to 1.29)1.11(0.92 to 1.33)
 Phet:0.4740.5100.7760.909
Never-smokers
 SALIA (1985–94)1.09(0.94 to 1.26)1.03(0.91 to 1.17)1.04(0.80 to 1.35)1.02(0.81 to 1.27)
 SAPALDIA (1991)1.24(0.85 to 1.79)1.25(0.86 to 1.80)0.90(0.19 to 4.30)0.81(0.17 to 3.77)
 Overall effect1.11(0.97 to 1.27)1.05(0.93 to 1.18)1.04(0.80 to 1.34)1.01(0.81 to 1.26)
 Phet:0.5380.3300.8580.774
  • Bold type denotes statistical significance, p <0.05. phet, p Value for heterogeneity.

  • Only outcomes available for both SALIA and SAPALDIA are included—analyses of phlegm alone could not be conducted in SALIA due to questionnaire wording.

  • ESCAPE, European Study of Cohorts for Air Pollution Effects; PM, particulate matter; SALIA, Study on the influence of Air pollution on Lung function, Inflammation and Aging; SAPALDIA, Swiss cohort study on Air Pollution And Lung and heart Diseases in Adults.