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Table 3 Associations between habitual PA levels and COPD incidence when exposed to different PM2.5 levels

From: Risk/benefit tradeoff of habitual physical activity and air pollution on chronic pulmonary obstructive disease: findings from a large prospective cohort study

PA levels a

 

Low-level PM2.5

Moderate-level PM2.5

High-level PM2.5

Case

HR (95% CI) b

P

HR (95% CI) b

P

HR (95% CI) b

P

Self-reported PA

 Low

1495

1.000

–

1.000

–

1.000

–

 Moderate

2530

0.786 (0.698, 0.884)

<0.0001

0.727 (0.65, 0.812)

<0.0001

0.792 (0.711, 0.882)

<0.0001

 High

2409

0.714 (0.633, 0.806)

<0.0001

0.707 (0.631, 0.792)

<0.0001

0.751 (0.672, 0.84)

<0.0001

 Trend test

–

 

<0.0001

 

<0.0001

 

<0.0001

Objectively measured PA

 Low

253

1.000

–

1.000

–

1.000

–

 Moderate

434

0.835 (0.651, 1.072)

0.157

0.696 (0.549, 0.883)

0.003

0.752 (0.587, 0.962)

0.024

 High

403

0.656 (0.489, 0.881)

0.005

0.571 (0.429, 0.76)

<0.0001

0.696 (0.523, 0.927)

0.013

 Trend test

–

 

0.005

 

0.007

 

0.001

  1. The bold type represents the statistically significant differences (p < 0.05)
  2. Abbreviations: PM2.5 particulate matter with aerodynamic diameter < 2.5 μm, HR hazard ratio, CI confidence interval, PA physical activity, COPD chronic obstructive pulmonary diseases
  3. a Self-reported PA levels were defined according to a standard scoring criteria of International Physical Activity Questionnaire (IPAQ): low (< 600 MET-min/week), moderate (600 to 3000 MET-min/week), and high (≥ 3000 MET-min/week), and objectively measured PA levels were defined by objectively measured PA tertiles [< 24.32 milli-gravity (mg), 24.32 to 30.70 mg, and ≥ 30.70 mg]
  4. bAll results were calculated fully adjusted by covariates in Model 3: age at enrolment, sex, ethnicity, household income, employment status, education, Townsend deprivation index, smoking status, alcohol intake frequency, fruit and vegetable intake, body mass index (BMI) and secondhand smoke exposure