Relationship between airway obstruction and incidence of metabolic syndrome in Korea: a community-based cohort study

Figures & data

Figure 1 Study population and design.

Note: *Airflow obstruction: forced expiratory volume in 1 second/forced vital capacity ratio < 0.7.
Abbreviation: MetS, metabolic syndrome.

Table 1 Baseline characteristics of men and women subjects included in the study

Characteristics	Men (n = 1,840)	Women (n = 1,764)	Total (n = 3,604)	P-value
Age (years), mean	50.8 ± 8.5	50.0 ± 8.3	50.5 ± 8.4	0.004
BMI (kg/m^2), mean	24.0 ± 2.7	23.8 ± 2.7	23.9 ± 2.7	0.015
COPD, n (%)	218 (11.8)	34 (1.9)	252 (7.0)	<0.001
Hypertension, n (%)	505 (27.4)	329 (18.7)	834 (23.1)	<0.001
Diabetes mellitus, n (%)	110 (6.0)	44 (2.5)	154 (4.3)	<0.001
Income quartile, n (%)				<0.001
First	436 (23.9)	543 (31.6)	979 (27.6)
Second	561 (30.7)	545 (31.7)	1,106 (31.2)
Third	640 (35.0)	510 (29.6)	1,150 (32.4)
Fourth	189 (10.4)	123 (7.1)	312 (8.8)
Smoking status, n (%)				<0.001
Never smoker	420 (22.9)	1,673 (96.3)	2,093 (58.6)
Ex-smoker	605 (33.0)	21 (1.2)	626 (17.5)
Current smoker	809 (44.1)	43 (2.5)	852 (23.9)
Smoking, pack-year	23.1 ± 16.7	23.6 ± 16.8	9.4 ± 9.5	<0.001
FEV1, % predicted, mean	108.3 ± 15.8	117.8 ± 16.8	112.9 ± 17.0	<0.001
FVC, % predicted, mean	103.1 ± 13.5	108.1 ± 14.6	105.6 ± 14.3	<0.001
Physical activity,a n (%)				0.002
None/mild	835 (46.4)	823 (47.9)	1,658 (47.1)
Moderate	613 (34.1)	642 (37.3)	1,255 (35.7)
Vigorous	352 (19.6)	254 (14.8)	606 (17.2)

Notes: Data are presented as mean ± standard deviation or n (%).

a Defined as none/mild: 0–29 minutes/day; moderate 30–60 minutes/day; vigorous ≥60 minutes/day.

Abbreviations: BMI, body mass index; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity.

Table 2 Association between metabolic syndrome and lung function impairment at 4 years of follow-up

Characteristic	Men OR (95% CI)	P-value	Women OR (95% CI)	P-value	Total OR (95% CI)	P-value
Age	1.02 (1.00–1.05)	0.040	1.08 (1.05–1.10)	<0.001	1.05 (1.03–1.07)	<0.001
BMI	1.26 (1.18–1.34)	<0.001	1.31 (1.23–1.40)	<0.001	1.29 (1.23–1.35)	<0.001
Smoking	1.73 (1.06–2.81)	0.035	1.30 (0.29–5.88)	0.730	1.33 (0.97–1.83)	0.082
COPD	1.76 (1.04–2.96)	0.028	0.35 (0.07–1.92)	0.229	1.23 (0.76–1.97)	0.401
Physical activity	0.89 (0.19–4.30)	0.875	1.08 (0.28–4.19)	0.914	1.08 (0.40–2.92)	0.877

Note: Data are presented as odds ratio (OR) (95% confidence interval [CI]), adjusted for age, body mass index (BMI), COPD, physical activity, and metabolic syndrome incidence in multivariable logistic regression analysis.

Figure 2 Incidence of metabolic syndrome in patients with COPD at 4 years of follow-up.

Notes: Data are expressed as number and percentage. Metabolic syndrome developed in 11.6% of the total subjects (419/3,604). Incidence of metabolic syndrome in patients with COPD was compared to incidence in patients without COPD, in both sexes.

Figure 3 Individual components of metabolic syndrome in normal and COPD patients. (A) Individual component changes (expressed as percentage) in metabolic syndrome in normal subjects. (B) Individual component changes (expressed as percentage) in metabolic syndrome in subjects with COPD.

Notes: Individual component is defined as central obesity (with waist circumference cutoff points of >90 cm for men and >80 cm for women), an elevated triglyceride (TG) level (≥1.7 mmol/L or undergoing drug treatment for elevated triglyceride levels), reduced high-density lipoprotein cholesterol (HDL-C) level (,1.0 mmol/L [men] and <1.3 mmol/L [women], or drug treatment for reduced HDL-C), elevated blood pressure (≥130 mmHg systolic, ≥85 mmHg diastolic, or antihypertensive drug treatment in patients with a history of hypertension [HTN]), and an elevated fasting plasma glucose concentration (≥5.6 mmol/L or drug treatment for diabetes).

Data availability

The data are not available for public access because of patient privacy concerns.