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. 2020 May 13;18:134. doi: 10.1186/s12916-020-01570-5

Table 3.

Results of stratified analyses by habitual physical activity and PM2.5 quartiles in Taiwanese adults

Stratified by PM2.5 1st quartile 2nd quartile 3rd quartile 4th quartile
% difference P % difference P % difference P % difference P
FVC
 Low PA 0.14 (− 0.08, 0.35) 0.209 0.09 (− 0.09, 0.26) 0.326 0.17 (0.01, 0.33) 0.036 − 0.20 (− 0.35, − 0.05) 0.009
 Moderate PA 0.49 (0.26, 0.72) < 0.001 0.43 (0.23, 0.62) < 0.001 0.45 (0.27, 0.63) < 0.001 0.14 (− 0.02, 0.31) 0.088
 High PA 0.82 (0.57, 1.07) < 0.001 1.23 (1.01, 1.46) < 0.001 0.87 (0.65, 1.09) < 0.001 0.57 (0.37, 0.76) < 0.001
 Per 10 MET-h 0.14 (0.08, 0.19) < 0.001 0.23 (0.17, 0.28) < 0.001 0.20 (0.15, 0.25) < 0.001 0.20 (0.15, 0.24) < 0.001
FEV1
 Low PA 0.03 (− 0.16, 0.22) 0.766 0.23 (0.06, 0.40) 0.010 −0.14 (− 0.29, 0.02) 0.078 − 0.06 (− 0.22, 0.09) 0.416
 Moderate PA 0.43 (0.22, 0.63) < 0.001 0.33 (0.14, 0.52) 0.001 0.13 (−0.04, 0.31) 0.136 0.44 (0.27, 0.60) < 0.001
 High PA 0.93 (0.70, 1.16) < 0.001 1.13 (0.90, 1.35) < 0.001 0.51 (0.30, 0.72) < 0.001 1.10 (0.90, 1.30) < 0.001
 Per 10 MET-h 0.22 (0.17, 0.27) < 0.001 0.18 (0.13, 0.23) < 0.001 0.14 (0.09, 0.19) < 0.001 0.20 (0.19, 0.22) < 0.001
MMEF
 Low PA − 0.49 (− 0.78, − 0.2) 0.001 0.26 (− 0.01, 0.54) 0.061 0.13 (−0.13, 0.39) 0.320 −0.07 (− 0.33, 0.19) 0.581
 Moderate PA 0.20 (− 0.11, 0.52) 0.202 0.08 (− 0.22, 0.39) 0.594 0.29 (0.00, 0.58) 0.048 0.21 (−0.07, 0.50) 0.140
 High PA 1.04 (0.70, 1.40) < 0.001 1.00 (0.65, 1.36) < 0.001 0.33 (−0.01, 0.68) 0.060 0.76 (0.43, 1.09) < 0.001
 Per 10 MET-h 0.31 (0.23, 0.39) < 0.001 0.22 (0.14, 0.30) < 0.001 0.10 (0.01, 0.18) 0.021 0.13 (0.05, 0.20) 0.001
Stratified by PA Inactive PA Low PA Moderate PA High PA
% difference P % difference P % difference P % difference P
FVC
 2nd quartile − 1.59 (− 1.73, − 1.45) < 0.001 − 0.86 (− 1.06, − 0.65) < 0.001 − 1.28 (− 1.50, − 1.06) < 0.001 − 1.13 (− 1.16, − 1.11) < 0.001
 3rd quartile − 2.32 (− 2.48, − 2.15) < 0.001 − 1.20 (− 1.44, − 0.96) < 0.001 − 1.84 (− 2.10, − 1.58) < 0.001 − 2.62 (− 2.64, − 2.60) < 0.001
 4th quartile − 4.96 (− 5.17, − 4.75) < 0.001 − 4.14 (− 4.44, − 3.84) < 0.001 − 4.40 (− 4.72, − 4.07) < 0.001 − 4.55 (− 4.57, − 4.52) < 0.001
 Per 10 μg/m3 − 2.20 (− 2.31, − 2.09) < 0.001 − 1.97 (− 2.12, − 1.82) < 0.001 −2.48 (− 2.50, − 2.47) < 0.001 − 3.07 (− 3.26, − 2.87) < 0.001
FEV1
 2nd quartile − 1.81 (− 1.96, − 1.67) < 0.001 − 1.16 (− 1.36, − 0.95) < 0.001 − 1.82 (− 2.04, − 1.59) < 0.001 − 2.52 (− 2.77, − 2.27) < 0.001
 3rd quartile − 2.63 (− 2.80, − 2.46) < 0.001 − 1.90 (− 2.14, − 1.67) < 0.001 −2.75 (− 3.01, − 2.49) < 0.001 − 3.78 (− 4.08, − 3.48) < 0.001
 4th quartile − 5.05 (− 5.27, − 4.83) < 0.001 − 4.60 (− 4.91, − 4.29) < 0.001 − 5.38 (− 5.71, − 5.05) < 0.001 − 6.18 (− 6.57, − 5.80) < 0.001
 Per 10 μg/m3 − 2.68 (− 2.80, − 2.57) < 0.001 − 2.31 (− 2.47, − 2.16) < 0.001 −2.87 (− 3.04, − 2.70) < 0.001 − 3.36 (− 3.57, − 3.16) < 0.001
MMEF
 2nd quartile − 3.16 (− 3.38, − 2.94) < 0.001 − 2.13 (− 2.45, − 1.80) < 0.001 − 2.88 (− 3.23, − 2.54) < 0.001 − 3.92 (− 4.31, − 3.54) < 0.001
 3rd quartile − 4.65 (− 4.90, − 4.40) < 0.001 − 3.45 (− 3.82, − 3.08) < 0.001 − 5.02 (− 5.42, − 4.62) < 0.001 − 6.24 (− 6.69, − 5.78) < 0.001
 4th quartile − 6.34 (− 6.65, − 6.02) < 0.001 − 4.68 (− 5.14, − 4.22) < 0.001 − 6.41 (− 6.90, − 5.91) < 0.001 − 7.91 (− 8.46, − 7.35) < 0.001
 Per 10 μg/m3 − 3.30 (− 3.46, − 3.13) < 0.001 − 2.56 (− 2.79, − 2.33) < 0.001 − 3.03 (− 3.28, − 2.78) < 0.001 − 3.81 (− 4.11, − 3.51) < 0.001

Lung function was logarithmically transformed to normalise the data for analysis and then the original scale was transformed back to present the effects as percentage (%) difference in lung function parameters with 95% confidence interval for every 10 MET-h increase in PA or with inactive PA as the reference and for each 10 μg/m3 increase of PM2.5 or with the first quartile of the PM2.5 as the reference

All results were fully adjusted for age, sex, educational level, body mass index, season, year, physical labour at work, smoking, drinking, vegetable intake, fruit intake, occupational exposure to dust and organic solvent, hypertension, diabetes, dyslipidaemia, self-reported cardiovascular disease, and self-reported cancer

The 1st, 2nd, 3rd, and 4th quartile of PM2.5 was < 21.67, 21.67–24.14, 24.14–28.81, and ≥ 28.81 μg/m3, respectively

PA physical activity, FVC forced vital capacity, FEV1 forced expiratory volume in 1 s, MMEF maximum mid-expiratory flow