A cross-sectional study on the pulmonary function of residents in two urban areas with different PM10 concentrations: data from the fourth Korea national health and nutrition examination survey (KNHANES) 2007–2009

Table 2 The results of pulmonary function test and the number for categorization of lung disease of subjects according to city of residence

Variables	Pulmonary function tests - Mean (Standard error)			Categorization of lung disease - N (%)
Variables	FEV1p	FVCp	FEV1/FVC	Normal^a	Obstruction^b	Restriction^c
Total
Seoul	91.45 (0.61)	92.10 (0.56)	0.80 (0.004)	587 (81.01)	68 (7.41)	94 (11.58)
Jeju	94.81 (1.74)	95.58 (0.96)	0.82 (0.008)	69 (86.64)	5 (3.51)	7 (9.85)
p value	0.071	0.002	0.167	0.258
Male
Seoul	90.24 (0.73)	91.26 (0.68)	0.79 (0.005)	236 (76.52)	51 (10.60)	53 (12.88)
Jeju	97.23 (1.19)	96.37 (1.41)	0.82 (0.005)	34 (94.74)	4 (4.29)	1 (0.97)
p value	< 0.001	0.001	0.001	0.001
Female
Seoul	92.71 (0.82)	92.97 (0.67)	0.81 (0.004)	351 (85.63)	17 (4.12)	41 (10.25)
Jeju	92.44 (2.56)	94.81 (1.28)	0.81 (0.013)	35 (78.71)	1 (2.74)	6 (18.54)
p value	0.922	0.208	0.971	0.229

p value were calculated by T-test to compare Seoul with Jeju, or chi-square test to compare categorization of lung disease
FEV1p predicted values of forced expiratory volume in 1 s, FVCp predicted values of forced vital capacity, FEV1/FVC FEV1/FVC ratio
^aNormal included subjects who had either an FEV1/FVC ≥0.70 and FVCp ≥80%
^bObstruction included subjects with FEV1/FVC < 0.70
^cRestriction included subjects who had either an FEV1/FVC ≥0.70 and FVCp < 80%

ISSN: 2052-4374