TABLE 5

Lung function subgroup analyses for fine particulate matter with diameter <2.5 μm (PM2.5) and nitrogen dioxide (NO2)#

FEV1 mLFVC mLFEV1/FVC
PM2.5 per 5 μg·m−3NO2 per 10 μg·m−3PM2.5 per 5 μg·m−3NO2 per 10 μg·m−3PM2.5 per 5 μg·m−3NO2 per 10 μg·m−3
β (95% CI)Interaction p-valueβ (95% CI)Interaction p-valueβ (95% CI)Interaction p-valueβ (95% CI)Interaction p-valueβ (95% CI)Interaction p-valueβ (95% CI)Interaction p-value
Sex<0.001<0.001<0.001<0.0010.9280.883
 Male−102.32 (−118.16– −86.48)−41.22 (−45.44– −37.00)−78.48 (−97.42– −59.54)−40.85 (−45.89– −35.81)−9.52 (−11.25– −7.80)−2.27 (−2.73– −1.80)
 Female−68.14 (−78.68– −57.59)−28.01 (−30.82– −25.21)−50.47 (−63.28– −37.67)−27.66 (−31.06– −24.26)−9.79 (−11.26– −8.32)−2.25 (−2.65– −1.86)
Age0.5740.1130.1870.014<0.001<0.001
 <65 years−83.63 (−93.85– −73.40)−32.55 (−37.27– −31.83)−65.06 (−77.40– −52.71)−34.86 (−38.15– −31.58)−8.92 (−10.11– −7.73)−2.04 (−2.36– −1.72)
 ≥65 years−85.32 (−108.62– −62.01)−31.64 (−37.82– −25.47)−54.05 (−81.85– −26.25)−27.41 (−34.78– −20.05)−13.73 (−16.91– −10.54)−3.50 (−4.35– −2.65)
Obesity0.0680.0030.4600.0820.0050.005
 Non-obese−78.68 (−89.31– −68.04)−31.69 (−34.51– −28.87)−58.93 (−71.78– −46.08)−31.65 (−35.05– −28.24)−9.07 (−10.36– −7.79)−2.07 (−2.41– −1.73)
 Obese−95.53 (−115.24– −75.82)−40.36 (−45.68– −35.04)−76.78 (−100.30– −53.27)−40.78 (−47.12– −34.45)−10.99 (−13.32– −8.67)−2.61 (−3.24– −1.98)
Smoking status0.388<0.001<0.001<0.001<0.001<0.001
 Never-smoker−84.49 (−96.74– −72.25)−38.11 (−41.37– −34.85)−76.56 (−91.51– −61.60)−41.89 (−45.87– −37.91)−6.91 (−8.35– −5.47)−1.61 (−2.00– −1.23)
 Current or past  smoker−87.08 (−101.61– −72.55)−30.42 (−34.28– −26.56)−49.66 (−66.87– −32.46)−24.42 (−28.99– −19.85)−13.80 (−15.59– −12.00)−3.31 (−3.79– −2.83)
Household income<0.001<0.001<0.001<0.001<0.001<0.001
 <GBP 31 000−78.85 (−93.56– −64.13)−35.76 (−39.79– −31.73)−95.83 (−112.86– −78.79)−46.92 (−51.58– −42.25)−13.70 (−15.49– −11.91)−3.46 (−3.96– −2.97)
 ≥GBP 31 000−39.12 (−52.30– −25.94)−21.81 (−25.24– −18.37)−31.69 (−46.76– −16.62)−22.15 (−26.08– −18.23)−6.38 (−7.82– −4.95)−1.41 (−1.78– −1.03)
Asthma status0.0020.0330.0940.3190.0130.113
 Never had  asthma−84.84 (−94.61– −75.08)−33.93 (−36.53– −31.33)−63.17 (−75.10– −51.24)−33.21 (−36.38– −30.04)−9.78 (−10.92– −8.64)−2.27 (−2.57– −1.96)
 Ever had  asthma−70.01 (−99.76– −40.26)−33.13 (−41.08– −25.17)−54.57 (−89.32– −19.81)−34.12 (−43.40– −24.85)−9.25 (−13.30– −5.21)−2.43 (−3.51– −1.34)
Occupational status0.001<0.0010.002<0.0010.4310.594
 Non-“at-risk”  occupation−71.88 (−83.25– −60.51)−30.88 (−33.87– −27.89)−57.95 (−71.67– −44.24)−32.20 (−35.81– −28.59)−6.94 (−8.25– −5.62)−1.57 (−1.92– −1.22)
 “At-risk”  occupation−183.85 (−271.13– −96.56)−77.71 (−101.86– −53.57)−192.19 (−296.36– −88.01)−91.28 (−120.11– −62.46)−9.18 (−19.57–1.20)−1.81 (−4.71–1.09)

FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity. #: adjusted for age (continuous), age-squared, sex, height, body mass index (kg·m−2), household income (<GBP 31 000/≥GBP 31 000), education level (lower vocational or less/higher vocational or more), smoking status (never/former/current) and passive smoking exposure at home (none/any).