Prevalence of airflow limitation in subjects undergoing comprehensive health examination in Japan: Survey of Chronic Obstructive pulmonary disease Patients Epidemiology in Japan

Figures & data

Table 1 Characteristics of the subjects enrolled in the survey

Characteristics	All (N=22,293)	Male (n=14,013)	Female (n=8,280)
Age (years)
Mean ± SD	54.7±9.6	55.2±9.8	53.8±9.3
40–49; n (%)	7,759 (34.8)	4,661 (33.3)	3,098 (37.4)
50–59; n (%)	7,706 (34.6)	4,812 (34.3)	2,894 (35.0)
≥60; n (%)	6,828 (30.6)	4,540 (32.4)	2,288 (27.6)
BMI (kg/m^2)
Mean ± SD	23.0±3.3	23.7±3.1	21.9±3.3
Smoking history
Missing data	100	71	29
None; n (%)	11,212 (50.5)	4,354 (31.2)	6,858 (83.1)
Past; n (%)	6,696 (30.2)	5,858 (42.0)	838 (10.2)
Current; n (%)	4,285 (19.3)	3,730 (26.8)	555 (6.7)

Abbreviations: BMI, body mass index; SD, standard deviation.

Table 2 Comparison of age distribution by sex between the survey subjects and Japanese general population

Sex	Age group (years)	Survey subjects, n (%)	Japanese general populationa, n (%)
Male	40–49	4,661 (33.3)	8,428,344 (24.9)
	50–59	4,812 (34.3)	8,097,065 (23.9)
	60–69	3,184 (22.7)	8,842,242 (26.1)
	70+	1,356 (9.7)	8,548,638 (25.2)
Female	40–49	3,098 (37.4)	8,346,637 (21.7)
	50–59	2,894 (35.0)	8,211,168 (21.4)
	60–69	1,773 (21.4)	9,405,180 (24.5)
	70+	515 (6.2)	12,486,874 (32.5)
Total		22,293 (100.0)	72,366,148 (100.0)
Male subtotal		14,013 (62.9)	33,916,289 (46.9)
Female subtotal		8,280 (37.1)	38,449,859 (53.1)

Note:

a These data are taken from National population census data in 2010.²⁶

Table 3 Prevalence of airflow limitation among total subjects by age group and sex

Age (years)	FEV1/FVC ≥0.7, n (%)	FEV1/FVC <0.7			Total n (%)
		% predicted FEV1 ≥80% (Stage I), n (%)	% predicted FEV1 <80% (Stage II–IV), n (%)	Subtotal (Stage I–IV), n (%)
All
40–49	7,630 (98.3)	53 (0.7)	76 (1.0)	129 (1.7)	7,759 (100)
50–59	7,465 (96.9)	103 (1.3)	138 (1.8)	241 (3.1)	7,706 (100)
≥60	6,236 (91.3)	277 (4.1)	315 (4.6)	592 (8.7)	6,828 (100)
Total	21,331 (95.7)	433 (1.9)	529 (2.4)	962 (4.3)	22,293 (100)
Male
40–49	4,564 (97.9)	40 (0.9)	57 (1.2)	97 (2.1)	4,661 (100)
50–59	4,618 (96.0)	77 (1.6)	117 (2.4)	194 (4.0)	4,812 (100)
≥60	4,042 (89.0)	221 (4.9)	277 (6.1)	498 (11.0)	4,540 (100)
Total	13,224 (94.4)	338 (2.4)	451 (3.2)	789 (5.6)	14,013 (100)
Female
40–49	3,066 (99.0)	13 (0.4)	19 (0.6)	32 (1.0)	3,098 (100)
50–59	2,847 (98.4)	26 (0.9)	21 (0.7)	47 (1.6)	2,894 (100)
≥60	2,194 (95.9)	56 (2.4)	38 (1.7)	94 (4.1)	2,288 (100)
Total	8,107 (97.9)	95 (1.1)	78 (0.9)	173 (2.1)	8,280 (100)

Abbreviations: FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity.

Table 4 Prevalence of airflow limitation among smokers by age group and sex

Age (years)	FEV1/FVC ≥0.7, n (%)	FEV1/FVC <0.7			Total n (%)
		% predicted FEV1 ≥80% (Stage I), n (%)	% predicted FEV1 <80% (Stage II–IV), n (%)	Subtotal (Stage I–IV), n (%)
All
40–49	3,675 (97.8)	33 (0.9)	48 (1.3)	81 (2.2)	3,756 (100)
50–59	3,854 (95.6)	68 (1.7)	109 (2.7)	177 (4.4)	4,031 (100)
≥60	2,785 (87.2)	180 (5.6)	229 (7.2)	409 (12.8)	3,194 (100)
Total	10,314 (93.9)	281 (2.6)	386 (3.5)	667 (6.1)	10,981 (100)
Male
40–49	2,991 (97.8)	29 (0.9)	39 (1.3)	68 (2.2)	3,059 (100)
50–59	3,350 (95.2)	63 (1.8)	105 (3.0)	168 (4.8)	3,518 (100)
≥60	2,615 (86.8)	173 (5.7)	223 (7.4)	396 (13.2)	3,011 (100)
Total	8,956 (93.4)	265 (2.8)	367 (3.8)	632 (6.6)	9,588 (100)
Female
40–49	684 (98.1)	4 (0.6)	9 (1.3)	13 (1.9)	697 (100)
50–59	504 (98.2)	5 (1.0)	4 (0.8)	9 (1.8)	513 (100)
≥60	170 (92.9)	7 (3.8)	6 (3.3)	13 (7.1)	183 (100)
Total	1,358 (97.5)	16 (1.1)	19 (1.4)	35 (2.5)	1,393 (100)

Abbreviations: FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity.

Table 5 Diagnosis of respiratory diseases (including past history) among smokers with (+) or without (−) airflow limitation

Diagnosis of respiratory diseases	Airflow limitation (−), n (%)	Airflow limitation (+), n (%)	Total, n
Diagnosis of respiratory diseases (+)
COPD or emphysema	142 (1.4)	63 (9.4)	205
Respiratory diseases other than COPD or emphysemaa	1,368 (13.3)	182 (27.3)	1,550
Diagnosis of respiratory diseases (−)	8,804 (85.4)	422 (63.3)	9,226
Total	10,314 (100)	667 (100)	10,981

Note:

a Other diseases include bronchial asthma, pneumonia, chronic bronchitis, bronchiectasis, tuberculosis, lung cancer, diffuse panbronchiolitis, and lung abscess.

Abbreviation: COPD, chronic obstructive pulmonary disease.

Table 6 COPD Assessment Test score distribution among smokers with (+) or without (−) airflow limitation

COPD Assessment Test score	Airflow limitation (−) (n=10,133)	Airflow limitation (+) (n=653)
0–5, n (%)	4,473 (44.1)	255 (39.1)
6–10, n (%)	3,414 (33.7)	231 (35.4)
11–15, n (%)	1,567 (15.5)	100 (15.3)
16+, n (%)	679 (6.7)	67 (10.3)
Mean ± SD	7.0±5.1	7.8±5.6

Abbreviations: COPD, chronic obstructive pulmonary disease; SD, standard deviation.

National population census data in 2010 Available from: http://www.e-stat.go.jp/SG1/estat/List.do?bid=000001034991&cycode=0Accessed March 12, 2015

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