TABLE 1

Baseline characteristics of the total sample and subgroups of healthy population, fixed ratio only- and lower limit of normal (LLN)-defined airway obstruction

Total sampleHealthy individuals#Fixed ratio onlyLLNp-values
Healthy versus fixed ratio onlyHealthy versus LLNfixed ratio only versus LLN
Subjects10 3298 4751278576
Males5849 (48)4067 (48)673 (53)265 (46)0.0020.360.008
Age years58.4±9.657.5±9.463.3±8.760.0±9.3<0.001<0.001<0.001
BMI    
 Overall kg·m-226.6±4.426.7±4.426.3±4.225.4±4.50.0013<0.001<0.001
 Underweight85 (1)57 (1)9 (1)13 (2)0.91<0.001<0.001
Normal weight4320 (38)3117 (37)514 (40)279 (49)0.023<0.0010.001
 Overweight4868 (43)3674 (44)542 (43)196 (34)0.46<0.001<0.001
 Obese2097 (18)1576 (19)210 (16)86 (15)0.060.260.42
Smoking
 Current
 smokers
2273 (20)1356 (16)389 (31)289 (50)<0.001<0.001<0.001
Former
 smokers
4262 (37)3134 (37)514 (40)194 (34)0.0320.110.009
 Never-smokers4842 (43)3926 (47)369 (29)90 (16)<0.001<0.001<0.001
 Pack-years19.2±18.016.9±16.324.5±19.730.3±21.5<0.001<0.001<0.001

Data are presented as n, n (%) or mean±sd, unless otherwise stated. BMI: body mass index. #: individuals who had completed spirometry without fixed ratio airway obstruction (FR-AO) nor LLN-AO. The percentages are for available data and not the total number. p-values <0.0015 are emphasised in bold, as they meet significance after Bonferroni correction for multiple comparisons.