Table 2.

Features of asthmatics and non-asthmatics in the UK Biobank (UKB)

Characteristics	Non-asthma (n = 239,158)	Asthma (n = 29,768)	P Value*	Mild Asthma (n = 25,322)	Moderate-severe Asthma (n = 4,446)	P Value**	P Value***
Age — yr	56 ± 8	55 ± 8	<0.0001	55 ± 8	57 ± 8	<0.0001	<0.0001
Female — %	54	57	<0.0001	56	61	<0.0001	<0.0001
Body mass index — kg/m2	27.2 ± 4.6	27.9 ± 5.2	<0.0001	27.8 ± 5.0	28.6 ± 5.6	<0.0001	<0.0001
Blood pressure — mm Hg
Systolic	138 ± 18.6	137 ± 17.9	<0.0001	137 ± 17.8	140 ± 18.2	<0.0001	0.0011
Diastolic	82 ± 10.1	82 ± 9.9	0.0006	82 ± 9.9	83 ± 9.7	0.0003	<0.0001
Hemoglobin — g/dL	14.2 ± 1.2	14.2 ± 1.2	0.07	14.2 ± 1.2	14.1 ± 1.2	0.0008	0.005
Hematocrit — %	41.1 ± 3.4	41.1 ± 3.4	0.9	41.1 ± 3.4	41.0 ± 3.4	0.02	0.5
Lung functions†
Forced expiratory volume in 1 second — % predicted	97.6 ± 16.2	89.4 ± 18.3	<0.0001	90.1 ± 18.0	84.9 ± 19.6	<0.0001	<0.0001
Forced vital capacity — liters	3.9 ± 1.0	3.7 ± 1.0	<0.0001	3.7 ± 1.0	3.4 ± 0.9	<0.0001	<0.0001
FEV1/FVC	0.77 ± 0.06	0.73 ± 0.08	<0.0001	0.74 ± 0.08	0.71 ± 0.10	<0.0001	<0.0001
White blood cells — x109/liter	6.7 ± 1.6	6.9 ± 1.7	<0.0001	6.9 ± 1.7	7.3 ± 1.8	<0.0001	<0.0001
Neutrophils	4.1 ± 1.3	4.3 ± 1.4	<0.0001	4.3 ± 1.4	4.6 ± 1.5	<0.0001	<0.0001
Eosinophils	0.16 ± 0.12	0.22 ± 0.16	<0.0001	0.22 ± 0.15	0.25 ± 0.18	<0.0001	<0.0001
Platelets — x109/liter	251 ± 56	259 ± 58	<0.0001	257 ± 58	269 ± 60	<0.0001	<0.0001
mtDNA-CN	67.8 ± 12.7	67.1 ± 12.7	<0.0001	67.3 ± 12.6	66.1 ± 12.8	<0.0001	<0.0001
Unadjusted mtDNA-CN residuals	0.020 ± 0.99	−0.040 ± 0.99	<0.0001	−0.02 ± 0.98	−0.118 ± 1.00	<0.0001	<0.0001
Adjusted mtDNA-CN residuals	0.005 ± 0.99	−0.021 ± 0.99	<0.0001	−0.020 ± 0.99	−0.030 ± 1.01	0.5	<0.0001

Mean ± SD

^*P value for non-asthmatics vs. asthmatics.

^**P value for mild asthmatics vs. moderate-severe asthmatics.

^***P value for ANOVA of non-asthmatics, mild asthmatics, and moderate-severe asthmatics.

^†Lung function available in subset where testing was done.

^‡Derived as the residuals of unadjusted mtDNA-CN regressed against age (restricted cubic splines with 4 degrees of freedom), sex, log-transformed white blood cell, red blood cell, lymphocyte, and neutrophil counts (all using restricted cubic splines with 4 degrees of freedom), platelet counts, and log-transformed eosinophil, basophil, and nucleated RBC counts. See Supplementary material for details. The residuals are standardized with mean of 0 and standard deviation of 1.