Table 4

Age and region-adjusted prevalence, stratified by various baseline variables

Characteristics	Men (prevalence (%), unless otherwise stated)						Women (prevalence (%) unless otherwise stated)
Characteristics	N	CB/E	AFO	UD	OD	CB/E_T	N	CB/E	AFO	UD	OD	CB/E_T
All	210 057	3.1	7.3	86.2	67.7	32.1	302 438	2.2	6.3	90.7	73.7	32.7
Sampling regions
Rural	118 837	3.2	9.2	86.1	60.5	34.8	167 727	2.1	7.7	90.3	64.4	37.8
Urban	91 220	2.9	4.8	86.6	78.0	28.4	134 711	2.4	4.8	91.5	83.3	27.4
Monthly household income (¥)
2500–4999	19 435	4.1	10.9	81.2	48.0	36.1	30 717	2.8	8.4	85.3	62.9	35.8
5000–9999	35 258	3.5	8.9	85.9	61.8	33.3	59 296	2.3	7.1	90.7	73.5	36.1
10 000–19 999	59 510	3.0	7.5	86.7	67.4	31.9	89 393	2.2	6.3	90.9	73.9	33.2
≥20 000	95 854	3.0	5.6	84.5	71.3	29.4	123 032	2.3	5.3	89.3	78.1	29.0
Highest education completed
No formal education	18 649	3.1	10.4	85.5	54.4	32.1	76 492	2.4	7.9	87.5	62.9	35.1
Primary school	70 086	3.2	8.1	84.4	62.6	34.5	95 035	2.2	6.2	89.7	72.3	31.2
Middle/high school	104 788	2.8	6.1	86.9	70.9	28.7	117 462	2.3	5.4	91.8	78.2	29.1
College/university	16 534	3.7	5.9	79.8	69.5	21.3	13 449	2.9	4.9	71.2	60.3	7.5
Smoking status
Never	30 282	3.3	5.9	83.8	70.3	32.2	287 117	2.1	5.9	91.2	76.2	31.6
Occasional	23 610	3.1	5.7	88.1	75.4	27.6	5522	2.7	10.2	90.1	59.6	39.5
Ex-regular	27 893	5.6	7.8	73.9	61.7	38.6	2644	6.1	14.7	77.7	40.1	43.4
Current regular	128 272	2.5	7.7	89.6	67.7	27.7	7155	2.3	12.9	92.9	59.5	30.7
Body mass index (kg/m²)
<18.5	9420	6.0	14.9	77.5	45.8	39.2	12 939	4.4	10.5	83.4	59.9	36.4
18.5 to <25	135 495	2.9	7.8	87.1	66.4	31.7	185 855	2.1	6.7	91.2	72.1	32.7
≥25	65 141	3.0	4.8	86.4	78.3	28.6	103 643	2.2	5.1	92.0	80.8	31.7
Age group (years)
30–39	29 565	1.1	4.7	96.0	81.8	19.7	48 173	1.0	5.9	96.8	80.5	22.7
40–49	59 162	1.4	5.0	93.9	78.9	21.0	93 450	1.4	4.9	94.8	81.0	25.0
50–59	63 671	2.7	6.9	88.6	71.9	28.9	93 771	2.4	5.9	90.0	75.8	32.2
60–69	41 310	5.6	10.3	79.8	63.5	35.2	50 406	3.8	8.4	85.5	68.8	37.4
70–79	16 349	7.5	13.7	78.3	59.1	41.1	16 638	4.7	12.0	86.0	65.4	40.7
Respiratory symptoms
None	188 303	2.1	6.3	92.1	74.6	24.6	277 510	1.5	5.8	94.6	77.4	27.1
Cough or breathlessness	19 287	10.1	13.1	72.5	59.6	38.2	22 717	8.5	11.0	77.4	69.2	38.5
Cough and breathlessness	2467	26.1	27.6	54.6	50.7	54.4	2211	26.1	20.5	53.7	59.5	52.6

AFO, air flow obstruction; CB/E, chronic bronchitis and/or emphysema; CB/E_T, participants currently under treatment for CB/E; OD, overdiagnosis; UD, underdiagnosis.