Analysis of the association of ANO3/MUC15, COL4A4, RRBP1, and KLK1 polymorphisms with COPD susceptibility in the Kashi population

Table 1 General characteristics of COPD patients and healthy subjects

Variables	Case (n = 541)	Control (n = 534)	p
Age, years (mean ± SD)	61.11 ± 12.26	54.86 ± 10.73	< 0.001
Gender (male/female), n	280/261	234/300	0.009
BMI (kg/m²) (mean ± SD)	23.56 ± 4.22	25.55 ± 4.17	< 0.001
Annual household income (CNY, yuan) (median, range)	16,939 (10,294–23,442)	15,298 (9762–23,057)	0.197
Smoking status (never/former/current), n	417/23/101	465/17/52	< 0.001
Smoking index^a(< 1/1 ≤ SI ≤ 400/400 < SI ≤ 800/SI > 800), n	417/ 98/16/10	465 /52/11/6	< 0.001
Coal consumption (yes/no), n	513/28	516/18	0.144
Wood consumption (yes/no), n	519/22	500/34	0.09
Time-to-first respiratory symptoms^b, years (≤ 5/5 < Time ≤ 10/ > 10), n	196/277/68	–	–
GOLD grade (1/2/3/4), n	150/292/82/17	–	–
Domiciliary oxygen therapy (nasal catheter/NIV/no), n	243/107/191	–	–
Pulmonary drugs (inhalant), n
Monotherapy (SABA/SAMA/LAMA)	11/5/79	-	-
Combination therapy (LABA + LAMA/ICS + LABA/ICS + LAMA + LABA)	85/138/30	-	-
Other (no/unavailable)	169/24	–	–
Pulmonary drugs (oral), n
Theophylline	174	–	–
LTRA	197	–	–
Other (no/unavailable)	139/36	–	–
Lung function (median, range)
FEV₁%	69.00 (53.92–82.00)	86.00 (74.00–98.00)	< 0.001
FEV₁/FVC	0.62 (0.55–0.66)	0.80 (0.75–0.86)	< 0.001

FEV1 Forced expiratory volume in 1 s, FVC Forced vital capacity, BMI Body mass index, NIV Noninvasive ventilation, SABA Short-acting beta2-agonist, SAMA Short-acting muscarinic antagonist, LABA Long-acting beta2-agonist, LAMA Long-acting muscarinic antagonist, ICS Inhaled corticosteroids, LTRA Leukotriene receptor antagonist, GOLD Global initiative for chronic obstructive lung disease
^aSmoking index = number × year
^bRespiratory symptoms, including cough, sputum production, and dyspnea

ISSN: 1471-2466