Table 1

Characteristics of participants
Male (n = 438) Female (n = 345)
Chi-squared Chi-squared
Japanese Chinese Japanese Chinese
Population (n (%)) 230 (52.5) 208 (47.5) 153 (44.3) 192 (55.7)
Age (y) (mean ± SD) 62.77 ± 8.53 65.84 ± 7.69 60.10 ± 7.62 63.86 ± 8.46
Body Mass Index (mean ± SD) 23.06 ± 3.30 23.61 ± 3.86 22.37 ± 3.06 24.02 ± 3.88
Job (n (%))   White collar 92 (51.4) 87 (48.6) 0.0056 50 (50.0) 50 (50.0) 0.0245
  Blue collar 63 (45.3) 76 (54.7) 33 (33.0) 67 (67.0)
  Housewife 0 (−) 0 (−) 70 (48.3) 75 (51.7)
  Retired 75 (64.1) 42 (35.9) 0 (−) 0 (−)
  Missing 0 (0.0) 3 (100.0) 0 (−) 0 (−)
Group (n (%))   Healthy 133 (63.0) 78 (37.0) < 0.0001 110 (47.6) 121 (52.4) 0.0817
  COPD 97 (42.7) 130 (57.3) 43 (37.7) 71 (62.3)
Cigarette smoking (n (%)) Healthy subjects
  Current smoker 43 (66.2) 22 (33.8) < 0.0001 9 (75.0) 3 (25.0) 0.0045
  Ex-smoker 61 (87.1) 9 (12.9) 5 (100.0) 0 (0.0)
  Non smoker 29 (43.3) 38 (56.7) 96 (45.7) 114 (54.3)
  Missing 0 (0.0) 9 (100.0) 0 (0.0) 4 (100.0)
COPD patients
  Current smoker 13 (28.3) 33 (71.7) 0.0007 2 (25.0) 6 (75.0) 0.0041
  Ex-smoker 67 (52.3) 61 (47.7) 6 (22.2) 21 (77.8)
  Non smoker 17 (40.5) 25 (59.5) 35 (50.0) 35 (50.0)
  Missing 0 (0.0) 11 (100.0) 0 (0.0) 9 (100.0)
Brinkman Index (n (%)) Healthy subjects
  0 29 (43.3) 38 (56.7) < 0.0001 96 (45.7) 114 (54.3) 0.0064
  0 < BI 500 44 (64.7) 24 (35.3) 13 (81.3) 3 (18.8)
  BI > 500 60 (89.6) 7 (10.4) 1 (100.0) 0 (0.0)
  Missing 0 (0.0) 9 (100.0) 0 (0.0) 4 (100.0)
COPD patients
  0 17 (40.5) 25 (59.5) < 0.0001 35 (50.0) 35 (50.0) 0.0036
  0 < BI 500 17 (27.9) 44 (72.1) 4 (28.6) 10 (71.4)
  BI > 500 63 (55.8) 50 (44.2) 4 (19.0) 17 (81.0)
  Missing 0 (0.0) 11 (100.0) 0 (0.0) 9 (100.0)
Heating sources (n (%)) Biomass, Coal, Animal dung 0 (0.0) 52 (100.0) < 0.0001 0 (0.0) 41 (100.0) < 0.0001
Gas, Electric, Steam 230 (60.1) 153 (39.9) 153 (50.7) 149 (49.3)
Missing 0 (0.0) 3 (100.0) 0 (0.0) 2 (100.0)

Yamaguchi et al.

Yamaguchi et al. BMC Public Health 2013 13:754   doi:10.1186/1471-2458-13-754

Open Data