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. 2020 Jan 6;20:6. doi: 10.1186/s12889-019-8028-y

Table 2.

Direct and indirect effects of leisure-time physical activity with lung function

Lung function Association
β (95%CI) Mediation (%)a
FEV1
 PA-Moderate
  Total 0.085 (0.049, 0.121)
  Direct 0.077 (0.041, 0.113)
  Indirect via CRP 0.009 (−0.001, 0.017) 10.05
 PA-High
  Total 0.149 (0.106, 0.193)
  Direct 0.130 (0.086, 0.174)
  Indirect via CRP 0.019 (0.010, 0.029) 12.99b
FVC
 PA-Moderate
  Total 0.131 (0.086, 0.176)
  Direct 0.123(0.078, 0.168)
  Indirect via CRP 0.009 (−0.001, 0.017) 6.58
 PA-High
  Total 0.207 (0.153, 0.262)
  Direct 0.188 (0.133,0.243)
  Indirect via CRP 0.020 (0.010, 0.029) 9.42b

CRP C-reactive protein, CI Confidence interval, FEV1 Forced expiratory volume in one second, FVC Forced vital capacity, PA Physical activity; β: regression coefficient

Models were adjusted for age, sex, education level, cigarette smoking, alcohol drinking, body mass index, cardiovascular diseases (angina, congestive heart failure and stroke), chronic lung diseases, cancer and dementia

Total effect is the effect of PA on lung function without CRP; direct effect is the effect of PA on lung function when controlling for CRP; indirect effect is the effect of PA on lung function via CRP

aMediation (%) is calculated by indirect effect/total effect ×100

bP<0.001