TABLE 2

Age, height, BMI, z-scores according to GLI-2012 for FEV₁, FVC and FEV₁/FVC by stepwise exclusion of subjects with respiratory diseases, symptoms and smoking history according to category A–D representing the Tromsø, Hordaland and the HUNT Study

	Female							Male
	Subjects n	Age years	Height cm	BMI kg·m⁻²	z-FEV₁	z-FVC	z-FEV₁/FVC	Subjects n	Age years	Height cm	BMI kg·m⁻²	z-FEV₁	z-FVC	z-FEV₁/FVC
Age 20–95 years
A: parent population	8048	56.9±15.4	163.7±6.5	26.6±4.7	−0.19±1.13	0.04±0.99	−0.46±0.92	6572	56.7±15.1	177.0±6.9	27.1±3.8	−0.29±1.11	−0.06±0.99	−0.42±1.03
B: subjects without cardinal symptoms	3357	54.9±14.9	164.3±6.2	25.7±4.2	0.06±1.02	0.22±0.94	−0.33±0.82	2907	55.3±14.6	177.5±6.7	26.7±3.6	−0.02±0.99	0.11±0.93	−0.23±0.88
C: never-smokers without cardinal symptoms	1570	55.3±16.3	163.8±6.3	25.8±4.4	0.15±0.98	0.23±0.92	−0.21±0.79	1190	52.0±15.1	178.4±6.6	26.5±3.3	0.06±0.93	0.10±0.90	−0.09±0.82
D: never-smokers without respiratory symptoms	1403	55.6±16.3	163.6±6.3	25.8±4.3	0.17±0.98	0.25±0.91	−0.20±0.78	1035	52.3±15.3	178.2±6.5	26.5±3.3	0.08±0.92	0.12±0.87	−0.09±0.82
Age 12–19 years
A: parent population	7711	16.1±1.8	165.4±6.3		0.09±1.02	0.05±0.98	−0.29±0.85	7904	16.0±1.8	174.4±9.5		−0.01±1.05	0.05±1.06	−0.11±0.96
B: subjects without cardinal symptoms	5767	16.0±1.8	165.5±6.3		−0.08±1.02	0.03±0.98	−0.25±0.85	5850	16.0±1.7	174.6±9.4		0.02±1.04	0.03±1.06	−0.03±0.94
C: never-smokers without cardinal symptoms	5032	15.9±1.8	165.4±6.3		−0.08±1.01	0.03±0.98	−0.23±0.84	5236	15.9±1.7	174.3±9.6		0.02±1.05	0.02±1.06	−0.02±0.94
D: never-smokers without respiratory symptoms	4166	15.9±1.8	165.3±6.4		−0.07±1.06	0.03±1.00	−0.21±0.83	4559	15.9±1.7	174.1±9.6		0.02±1.05	−0.01±1.06	−0.02±0.94

Data are presented as mean±sd. GLI: Global Lung Function Initiative; FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity; HUNT: Nord-Trøndelag Health Study; BMI: body mass index. Categories A–D as defined in [23] (A: parent population randomly selected persons; B: persons without obstructive lung disease, Modified Medical Research Council Dyspnoea Scale 0, no wheezing and no chronic cough; C: never-smokers; D: never-smokers without any respiratory symptoms).