Table 1

Personal characteristics and lung function level of children studied

Personal characteristicsRural (n=485)Urban (n=586)
Percent boys 43.3% 49.7%1-150
Age (years)
 Mean (SD) 10.8 (1.1) 10.2 (0.7)1-150
 Range  8–12  8–12
Height (cm)
 Mean (SD)135.0 (6.7)135.4 (7.0)1-150
 Range111–158114–155
Weight (kg)
 Mean (SD) 28.2 (4.4) 28.1 (4.8)1-150
 Range 20–54 17–50
Body mass (kg/m2)
 Mean (SD) 15.3 (1.4) 15.2 (1.7)
 Range 12.4–23.7 11.2–22.7
Lung function Rural (n=480) Urban (n=577)
FEV1 (l)
 Mean (SD)  1.60 (0.29)  1.66 (0.28)1-150
 Range  0.55–3.01  0.80–2.78
FVC (l)
 Mean (SD)  1.91 (0.35)  1.99 (0.34)1-150
 Range  0.85–3.48  1.13–3.27
FEV1/FVC (%)
 Mean (SD) 84.3 (8.0) 83.5 (6.9)
 Range 44.9–155.2 57.6–100.0
Age, sex and size adjusted lung function level (FEV1 and FVC)1-151
FEV1 (% predicted)
 Mean100.7 99.4
 95% CI 99.5 to 101.9 98.4 to 100.5
FVC (% predicted)
 Mean100.5 99.6
 95% CI 99.4 to 101.7 98.5 to 100.6
  • FEV1 = forced expiratory volume in one second; FVC = forced vital capacity.

  • 1-150 Significant urban-rural differences (p<0.05).

  • 1-151 Internally adjusted using the study population’s age, sex, height and body mass index.