Determinants of airflow limitation in Danish adults – findings from the Health2006 cohort

Figures & data

Figure 1 Selection and categorization of participants in the Health2006 cohort for present analyses.

Abbreviation: LLN, lower limit of normal.

Table 1 Self-reported characteristics of participants in the Health2006 study according to presence (cases) or absence (controls) of airflow limitation

	Controls n=2,646	Cases n=313	P-value
Smoking habits
Current smokers, %	22.4	41.9	<0.001
Never-smokers, %	41.3	19.8	<0.001
Pack years	19.5 (19.0)	26.0 (25.7)	<0.001
Alcohol consumption
Non-drinkers, %	5.6	6.7	NS
Weekly consumption, unitsa	8.0 (11.0)	8.0 (11.0)	NS
10 years of school or less, %	10.1	13.7	NS
Hormone replacement treatment (women only)
Yes, %	34.9	35.8	NS
Number of years	7.0 (8.0)	5.0 (8.0)	NS
Symptoms last 12 months
Rhinitis, %	51.9	56.1	NS
Asthma symptoms, %	2.5	17.0	<0.001
Dyspnoea at rest, %	26.9	48.5	<0.001
Dyspnoea during activity, %	6.5	10.0	0.021
Chronic bronchitis,b %	8.3	22.3	<0.001
Nightly respiratory symptoms, %	16.0	23.1	0.002
Wheezing, %	19.6	43.4	<0.001
Ever diagnosed with
Rhinitis, %	17.4	22.3	0.034
Asthma, %	8.8	20.9	<0.001
Eczema, %	4.5	7.0	NS
Hypertension, %	31.4	30.1	NS
Diabetes, %	4.4	4.5	NS
Hyper-cholesterolaemia, %	34.7	30.5	NS
Self-ratedc
Overall health (1–5), mean (SD)	2.5 (0.8)	2.7 (0.9)	<0.001
Exercise habits (1–5), mean (SD)	3.2 (1.0)	3.4 (1.0)	0.013
Dietary habits (1–5), mean (SD)	2.7 (0.6)	2.7 (0.6)	NS
Social position (1–5), mean (SD)	2.7 (0.6)	2.7 (0.6)	NS

Notes: Using Chi-square and Mann-Whitney U-test. Unless otherwise stated, numbers are reported as median (IQ-range).

a Calculated for people who reported a current alcohol consumption only.

b Self-reported cough with sputum for at least 3 months/year for at least two consecutive years.

c Measured on a scale from 1 to 5, where 1 is best.

Abbreviation: NS, not significant.

Table 2 Clinical characteristics of participants in the Health2006 study according to presence (cases) or absence (controls) of airflow limitation

	Controls n=2,646	Cases n=313	P-value
Sex, % men	46.5	37.4	0.002
Age, years	52.0 (17.0)	52.0 (15.0)	NS
BMIa (kg/m^2)	25.3 (5.0)	24.6 (5.0)	<0.001
Normal or underweight, %	43.3	54.5	<0.001
Overweight, %	39.1	33.0	0.035
Obese, %	17.6	12.5	0.021
Fat percentage, %	29.2 (13.0)	30.0 (14.0)	NS
FEV1, % predicted	101.0 (18.0)	83.0 (19.0)	<0.001
FVC, % predicted	105.0 (19.0)	106.0 (25.0)	NS
FEV1/FVC, %	79.5 (7.0)	65.8 (7.0)	<0.001
FeNO, ppb	16.0 (13.0)	14.0 (14.0)	<0.001
Fitness level, mlO2/kg/min	30.0 (11.0)	28.0 (12.0)	NS
Positive skin prick test, %	27.9	27.9	NS
Positive IgE,b %	21.8	19.3	NS
Systolic blood pressure, mmHg	124.0 (21.0)	128.5 (22.0)	NS

Notes: Using Chi-square and Mann-Whitney U-test. Unless otherwise stated, numbers are reported as median (IQ-range). Values in parentheses are IQ-range for the mean values.

a BMI: Body mass index, using following categories: Normal or underweight (≤24.9), overweight (25.0–29.9), obese (≥30.0). FEV₁: Forced expiratory volume in 1 second. FVC: Forced vital capacity. FeNO: Fractional exhaled nitric oxide.

b IgE: mmunoglobulin E. Positive for at least one of the four tested allergens: cat, grass, house dust mites and birch.

Abbreviation: NS, not significant.

Table 3 Factors associated with airflow limitation in the Health2006 cohort reported as odds ratios

	OR	95% CI	P-value
Sexa	1.61	1.20–2.16	0.002
BMIb
Overweight	3.07	1.97–4.78	<0.001
Obese	1.70	1.08–2.68	0.023
Agec
41–55 years	2.08	1.29–3.37	0.003
>55 years	2.29	1.66–3.15	<0.001
Positive specific IgE to aeroallergensd	1.44	1.18–1.98	0.041
Ever asthma	1.57	1.32–2.02	0.003
Smoking habitse
Current smoker	1.76	1.18–2.25	0.019
Former smoker	1.62	1.12–2.34	0.010

Notes: Adjusted for FEV₁.

a OR for women, compared to men.

b BMI: Body mass index. Reference group normal/underweight.

c Compared to age <41 years.

d IgE: Immunoglobulin E. Positive for at least one of the four tested allergens: cat, grass, house dust mites and birch.

e Compared to never-smokers.