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. 2023 Jun 13;13:9609. doi: 10.1038/s41598-023-36682-4

Table 2.

Association of five-knot group of air pollutant concentration with annual eGFR slope by a linear regression model.

Model 1 P-value Model 2 P-value
Regression coefficient 95% CI Regression coefficient 95% CI
CO, ppm 0.33 0.08
 < 0.42 0.00 [Reference] – 0.00 [Reference] –
 0.42 ≤ CO < 0.44 0.28 (− 0.91–1.46) 0.65 0.57 (− 0.88–2.01) 0.44
 0.44 ≤ CO < 0.47 0.16 (− 1.05–1.37) 0.80 0.47 (− 1.71–2.66) 0.67
 0.47 ≤ CO < 0.48 − 0.16 (− 1.35–1.03) 0.79 1.32 (− 1.58–4.22) 0.37
 0.48 ≤ CO < 0.49 0.78 (− 0.44–2.00) 0.21 2.38 (− 1.00–5.76) 0.17
 ≥ 0.49 0.36 (− 1.28–1.99) 0.67 2.08 (− 1.93–6.08) 0.31
NO, ppb 0.23 0.14
 < 2.36 0.00 [Reference] – 0.00 [Reference] –
 2.36 ≤ NO < 2.39 0.67 (− 0.53–1.86) 0.27 0.62 (− 0.81–2.04) 0.40
 2.39 ≤ NO < 2.41 0.93 (− 0.25–2.12) 0.12 0.87 (− 0.51–2.25) 0.21
 2.41 ≤ NO < 2.43 0.27 (− 0.90–1.44) 0.65 0.07 (− 1.22–1.36) 0.92
 2.43 ≤ NO < 2.55 0.01 (− 1.18–1.20) 0.98 − 0.18 (− 1.44–1.08) 0.78
 ≥ 2.55 0.62 (− 0.92–2.16) 0.43 − 0.02 (− 1.52–1.47) 0.98
NO2, ppb 0.69 0.15
 < 12.15 0.00 [Reference] – 0.00 [Reference] –
 12.15 ≤ NO2 < 13.19 0.18 (− 0.98–1.34) 0.76 0.05 (− 1.18–1.28) 0.93
 13.19 ≤ NO2 < 13.69 − 0.07 (− 1.25–1.11) 0.91 − 0.87 (− 2.33–0.59) 0.24
 13.69 ≤ NO2 < 13.91 − 0.20 (− 1.37–0.96) 0.73 − 0.21 (− 1.97–1.55) 0.82
 13.91 ≤ NO2 < 14.21 0.44 (− 0.74–1.63) 0.46 0.14 (− 1.84–2.13) 0.89
 ≥ 14.21 − 0.14 (− 1.80–1.53) 0.87 − 0.35 (− 2.71–2.02) 0.77
NOx, ppb 0.45 0.3
 < 14.53 0.00 [Reference] – 0.00 [Reference] –
 14.53 ≤ NOX < 15.66 0.25 (− 0.89–1.39) 0.66 − 0.05 (− 1.25–1.16) 0.94
 15.66 ≤ NOX < 16.10 0.13 (− 1.04–1.29) 0.83 − 0.79 (− 2.22–0.64) 0.28
 16.10 ≤ NOX < 16.28 − 0.33 (− 1.48–0.82) 0.57 − 0.69 (− 2.35–0.96) 0.41
 16.28 ≤ NOX < 16.54 0.51 (− 0.65–1.67) 0.39 − 0.13 (− 2.01–1.75) 0.90
 ≥ 16.54 − 0.01 (− 1.69–1.68) 0.99 − 0.53 (− 2.67–1.62) 0.63
O3, ppb 0.47 0.25
 < 30.92 0.00 [Reference] – 0.00 [Reference] –
 30.92 ≤ O3 < 31.31 − 0.20 (− 1.48–1.07) 0.75 − 0.16 (− 1.35–1.03) 0.79
 31.31 ≤ O3 < 31.53 − 0.13 (− 1.41–1.15) 0.85 0.33 (− 0.98–1.65) 0.62
 31.53 ≤ O3 < 31.71 − 0.53 (− 1.81–0.74) 0.41 0.76 (− 0.93–2.45) 0.38
 31.71 ≤ O3 < 31.89 0.31 (− 0.99–1.61) 0.64 1.77 (− 0.19–3.72) 0.08
 ≥ 31.89 0.06 (− 1.64–1.75) 0.95 1.58 (− 0.89–4.04) 0.21
PM10, μg/m3 0.38 0.05
 < 62.45 0.00 [Reference] – 0.00 [Reference] –
 62.45 ≤ PM10 < 63.62 0.54 (− 0.69–1.76) 0.39 0.86 (− 0.33–2.05) 0.15
 63.62 ≤ PM10 < 64.71 0.54 (− 0.71–1.78) 0.40 0.80 (− 0.57–2.17) 0.25
 64.71 ≤ PM10 < 65.22 0.20 (− 1.03–1.43) 0.75 1.64 (− 0.07–3.35) 0.06
 65.22 ≤ PM10 < 65.84 1.04 (− 0.22–2.29) 0.10 2.60 (0.62–4.58) 0.01
 ≥ 65.84 0.65 (− 1.01–2.32) 0.44 2.32 (− 0.18–4.83) 0.07
PM2.5, μg/m3 0.36 0.07
 < 34.31 0.00 [Reference] – 0.00 [Reference] –
 34.31 ≤ PM25 < 35.15 0.72 (− 0.57–2.01) 0.27 0.89 (− 0.36–2.15) 0.16
 35.15 ≤ PM25 < 36.06 0.69 (− 0.62–2.00) 0.30 1.11 (− 0.36–2.57) 0.14
 36.06 ≤ PM25 < 36.49 0.35 (− 0.95–1.64) 0.60 1.89 (0.04–3.74) 0.05
 36.49 ≤ PM25 < 36.99 1.17 (− 0.15–2.49) 0.08 2.85 (0.73–4.98) 0.01
 ≥ 36.99 0.80 (− 0.91–2.52) 0.36 2.65 (− 0.01–5.32) 0.05
SO2, ppb 0.65 0.26
 < 3.38 0.00 [Reference] – 0.00 [Reference] –
 3.38 ≤ SO2 < 3.50 0.80 (− 0.60–2.20) 0.26 1.07 (− 0.36–2.5) 0.14
 3.50 ≤ SO2 < 3.58 0.27 (− 1.11–1.65) 0.70 0.63 (− 0.75–2.00) 0.37
 3.58 ≤ SO2 < 3.67 0.17 (− 1.22–1.55) 0.81 0.02 (− 1.34–1.39) 0.97
 3.67 ≤ SO2 < 4.09 0.24 (− 1.15–1.63) 0.74 0.01 (− 1.41–1.43) 0.99
 ≥ 4.09 0.50 (− 1.19–2.19) 0.56  < 0.01 (− 1.68–1.69) 1.00

CO, carbon monoxide; NO, nitrogen monoxide; NO2, nitrogen dioxide; NOx, nitrogen oxide; O3, ozone; PM10, particulate matter < 10 μm in aerodynamic diameter; PM25, particulate matter < 2.5 μm in aerodynamic diameter; SO2, sulfur dioxide; ppb, parts per billion; ppm, parts per million; μg/m3, micrograms per cubic meter; Q, quartile; CI, confidence interval.

All studied air pollutant concentrations were categorized by their percentiles: 5, 27.5, 50, 72.5, and 95. Model 1 is estimated by linear regression model after putting a group of air pollutant concentrations. Independent variables in Model 2 are listed as independent variables in model 1, and age, sex, educational level, diabetes mellitus, hypertension, cerebrovascular accident, congestive heart failure, ischemic heart disease, gout, angiotensin-converting enzyme inhibitor/ angiotensin II receptor blocker, temperature, and log (urine protein creatinine ratio). The Type III tests of fixed effect P-value was shown at the same raw adjacency to the listed name of the air pollutant.