TRPM8 genetic variations associated with COPD risk in the Chinese Han population

Figures & data

Table 1 Characteristics and grouping of the study population

Characteristics	Cases	Controls	P-value	COPD with PH	COPD without PH	P-value
n	513	506		150	363
Age, years (mean±SD)	68.02±11.21	56.49±9.43	<0.001	70.03±12.37	67.19±10.60	0.190
Male, n%	432 (84.21)	414 (81.82)	0.318	126 (84.00)	306 (84.30)	1.000
Pack-years	43.08±21.71	39.45±19.58	<0.001	41.93±21.65	40.47±23.51	0.467
BMI, kg/m^2	23.75±2.57	24.18±2.48	0.575	24.16±2.27	23.57±2.69	0.051
FEV1 %, predicted	36.77±16.94	95.77±12.98	<0.001	35.67±16.10	37.23±18.64	0.138
FEV1/FVC	0.43±0.19	0.81±0.96	<0.001	0.43±0.15	0.45±0.26	0.004
GOLD classification	Level 3			Level 3	Level 3
PASP, mmHg				49.64±14.25	25.37±5.73	<0.001

Note: P<0.05 indicates statistical significance.

Abbreviations: BMI, body mass index; GOLD, Global initiative for chronic Obstructive Lung Disease; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; PASP, pulmonary artery systolic pressure; PH, pulmonary hypertension.

Table 2 Basic characteristics of SNPs in the enrolled population

SNPs	Chromosomes	Position	Gene	Allele	Risk of COPD				Risk of COPD with PH
					HWE-P	OR	95% CI	Allele, P-value	HWE-P	OR	95% CI	Allele, P-value
rs2362290	2q37.1	233916724	TRPM8	AG	0.061	1.03	0.85–1.24	0.781	0.291	0.8	0.60–1.07	0.130
rs9789675	2q37.1	233916914	TRPM8	AG	0.494	1.17	0.91–1.51	0.241	0.453	0.63	0.42–0.97	0.034*
rs9789398	2q37.1	233916979	TRPM8	CT	0.922	1.33	1.01–1.74	0.040*	0.609	1.59	1.03–2.44	0.034*
rs1003540	2q37.1	233917239	TRPM8	AG	0.065	0.99	0.82–1.19	0.912	0.394	1.28	0.96–1.70	0.394
rs1004478	2q37.1	233917250	TRPM8	CG	0.06	0.96	0.80–1.16	0.683	0.182	1.21	0.91–1.62	0.194

Note:

* P<0.05 indicates statistical significance.

Abbreviations: CI, confidence interval; HWE-P, P-value of Hardy–Weinberg equilibrium; OR, odds ratio; PH, pulmonary hypertension; SNP, single nucleotide polymorphism; TRPM8, transient receptor potential cation channel subfamily M member 8.

Table 3 Association between rs9789398 genotypes and the risk of COPD

Model	Genotype	Control	Case	Without adjustment		With adjustment
				OR (95% CI)	P-valuea	OR (95% CI)	P-valueb
Codominant	TT	377 (79.2%)	351 (73%)	1.00	0.069	1.00	0.2
	TC	93 (19.5%)	124 (25.8%)	1.43 (1.05–1.94)		1.37 (0.96–1.95)
	CC	6 (1.3%)	6 (1.2%)	1.07 (0.34–3.36)		1.29 (0.37–4.56)
Dominant	TT	377 (79.2%)	351 (73%)	1.00	0.024*	1.00	0.074
	TC–CC	99 (20.8%)	130 (27%)	1.41 (1.05–1.90)		1.37 (0.97–1.93)
Recessive	TT–TC	470 (98.7%)	475 (98.8%)	1.00	0.99	1.00	0.77
	CC	6 (1.3%)	6 (1.2%)	0.99 (0.32–3.09)		1.20 (0.34–4.25)
Overdominant	TT–CC	383 (80.5%)	357 (74.2%)	1.00	0.021*	1.00	0.082
	TC	93 (19.5%)	124 (25.8%)	1.43 (1.05–1.94)		1.37 (0.96–1.94)
Log additive				1.34 (1.02–1.77)	0.037*	1.32 (0.96–1.80)	0.088

Notes:

* P<0.05 indicates statistical significance.

a P-values were calculated by two-sided χ² tests or Fisher’s exact tests for each genotype distribution.

b P-values were calculated by unconditional logistic regression adjusted for age, sex, and smoking status.

Abbreviations: CI, confidence interval; OR, odds ratio.

Table 4 Association between TRPM8 and COPD by smoking status: stratified analysis

Reference SNP ID	Genotypes	Nonsmokers (n =247)			Former smokers (n =454)			Current smokers (n =318)
		COPD; n=126 (%)	Control; n=121 (%)	P-valuea	COPD; n=214 (%)	Control; n=240 (%)	P-valueb	COPD; n=173 (%)	Control; n=145 (%)	P-valueb
rs2362290	GG	11 (8.9)	9 (7.9)	0.713	16 (7.6)	24 (10.1)	0.399	14 (8.1)	9 (6)	0.589
	GA	61 (49.6)	55 (48.2)	0.759	106 (50.2)	114 (48.1)	0.865	69 (39.9)	67 (44.7)	0.474
	AA	51 (41.5)	50 (43.9)		89 (42.2)	99 (41.8)		90 (52)	74 (49.3)
rs9789675	AA	2 (1.6)	1 (0.9)	0.610	2 (1)	3 (1.3)	0.702	4 (2.4)	2 (1.4)	0.412
	GA	40 (32.5)	29 (27.4)	0.376	42 (20.3)	57 (24.6)	0.276	45 (26.8)	24 (16.2)	0.021*
	GG	81 (65.8)	76 (71.4)		163 (78.7)	172 (74.1)		119 (70.8)	122 (82.4)
rs9789398	CC	1 (0.8)	1 (1)	0.975	1 (0.5)	3 (1.3)	0.747	4 (2.5)	2 (1.4)	0.375
	TC	40 (32.8)	25 (23.8)	0.138	41 (20.7)	48 (21.3)	0.840	43 (26.7)	20 (13.7)	0.005*
	TT	81 (66.4)	79 (75.2)		156 (78.8)	174 (77.3)		114 (70.8)	124 (84.9)
rs1003540	AA	11 (9)	8 (7.3)	0.479	16 (7.6)	23 (9.9)	0.455	14 (8.2)	9 (6)	0.627
	AG	62 (50.8)	51 (46.4)	0.393	105 (50)	111 (47.8)	0.838	65 (38.2)	68 (45.3)	0.257
	GG	49 (40.2)	51 (46.4)		89 (42.2)	98 (42.2)		91 (53.5)	73 (48.7)
rs1004478	GG	8 (6.6)	13 (11.4)	0.319	23 (10.9)	17 (7.1)	0.151	28 (16.5)	18 (12)	0.388
	CG	60 (49.2)	60 (52.6)	0.124	97 (46.2)	112 (46.9)	0.775	73 (42.9)	72 (48)	0.603
	CC	54 (44.3)	41 (36)		90 (42.9)	110 (46)		69 (40.6)	60 (40)

Notes:

a P-values were calculated by logistic regression adjusted for age and sex in nonsmokers.

b P-values were calculated by logistic regression adjusted for age, sex, and pack-years in former and current smokers.

* P<0.05.

Abbreviations: SNP, single nucleotide polymorphism; TRPM8, transient receptor potential cation channel subfamily M member 8.

Table 5 Association between genotypes (rs9789675, rs9789398, and rs1004478) and the risk of PH in COPD

SNP	Model	Genotype	Control	Case	Without adjustment		With adjustment
					OR (95% CI)	P-valuea	OR (95% CI)	P-valueb
rs9789675	Codominant	GG	248 (70.2%)	115 (79.3%)	1.00	0.084	1.00	0.110
		GA	98 (27.8%)	29 (20%)	0.64 (0.40–1.02)		0.64 (0.40–1.04)
		AA	7 (2%)	1 (0.7%)	0.31 (0.04–2.53)		0.35 (0.04–2.90)
	Dominant	GG	248 (70.2%)	115 (79.3%)	1.00	0.036*	1.00	0.045
		GA–AA	105 (29.8%)	30 (20.7%)	0.62 (0.39–0.98)		0.6 (0.39–1.00)
	Recessive	GG–GA	346 (98%)	144 (99.3%)	1.00	0.260	1.00	0.330
		AA	7 (2%)	1 (0.7%)	0.34 (0.04–2.82)		0.39 (0.05–3.21)
	Overdominant	GG–AA	255 (72.2%)	116 (80%)	1.00	0.066	1.00	0.076
		GA	98 (27.8%)	29 (20%)	0.65 (0.41–1.04)		0.66 (0.41–1.05)
	Log additive	–	–	–	0.62 (0.40–0.96)	0.027*	0.64 (0.41–0.99)	0.037
rs9789398	Codominant	TT	237 (70.1%)	114 (79.7%)	1.00	0.082	1.00	0.100
		TC	96 (28.4%)	28 (19.6%)	0.61 (0.38–0.98)		0.61 (0.38–0.99)
		CC	5 (1.5%)	1 (0.7%)	0.42 (0.05–3.60)		0.47 (0.05–4.17)
	Dominant	TT	237 (70.1%)	114 (79.7%)	1.00	0.027*	1.00	0.034*
		TC–CC	101 (29.9%)	1 (1.7%)	0.60 (0.37–0.95)		0.60 (0.38–0.97)
	Recessive	TT–TC	333 (98.5%)	115 (80.4%)	1.00	0.46	1.00	0.540
		CC	5 (1.5%)	28 (19.6%)	0.47 (0.05–4.05)		0.53 (0.06–4.65)
	Overdominant	TT–CC	242 (71.6%)		1.00	0.04*	1.00	0.045*
		TC	96 (28.4%)		0.61 (0.38–0.99)		0.62 (0.38–1.00)
	Log additive	–	–	–	0.61 (0.39–0.95)	0.026*	0.62 (0.40–0.98)	0.034*
rs1004478	Codominant	CC	140 (39.4%)	73 (49.7%)	1.00	0.048*	1.00	0.055
		CG	175 (49.3%)	55 (37.4%)	0.60 (0.40–0.91)		0.60 (0.40–0.92)
		GG	40 (11.3%)	19 (12.9%)	0.91 (0.49–1.69)		0.88 (0.47–1.64)
	Dominant	CC	140 (39.4%)	73 (49.7%)	1.00	0.036*	1.00	0.036*
		CG–GG	215 (60.6%)	74 (50.3%)	0.66 (0.45–0.97)		0.66 (0.44–0.92)
	Recessive	CC–CG	312 (88.7%)	128 (87.1%)	1.00	0.600	1.00	0.690
		GG	40 (11.3%)	19 (12.9%)	1.17 (0.65–2.10)		1.13 (0.62–2.03)
	Overdominant	CC–GG	180 (50.7%)	92 (62.6%)	1.00	0.015*	1.00	0.018*
		CG	175 (49.3%)	55 (37.4%)	0.61 (0.41–0.91)		0.62 (0.42–0.93)
	Log additive	–	–	–	0.82 (0.61–1.10)	0.190	0.82 (0.61–1.10)	0.170

Notes:

* P<0.05 indicates statistical significance.

a P-values were calculated by two-sided χ² tests or Fisher’s exact tests for each genotype distribution.

b P-values were calculated by unconditional logistic regression adjusted for age, sex, and smoking status.

Abbreviations: CI, confidence interval; OR, odds ratio; PH, pulmonary hypertension; SNP, single nucleotide polymorphism.

Table 6 Haplotype association with response (n=508, adjusted for smoking status + sex + age)

	rs2362290	rs9789675	rs9789398	rs1003540	rs1004478	Frequency	OR (95% CI)	P-value
1	A	G	T	G	G	0.3463	1.00	–
2	G	G	T	A	C	0.3057	1.30 (0.92–1.84)	0.14
3	A	G	T	G	C	0.201	1.44 (0.98–2.12)	0.043*
4	A	A	C	G	C	0.1298	0.71 (0.43–1.16)	0.17
Rare	*	*	*	*	*	0.0173	1.40 (0.46–4.25)	0.56

Note: Global haplotype association: P-value, 0.051.

* P<0.05.

Abbreviations: CI, confidence interval; OR, odds ratio.

Figure 1 LD plots containing four SNPs from the TRPM8.

Notes: LD analysis of TRPM8 in the Chinese Han controls. LD is indicated using standard color schemes with red signifying very strong LD (LOD ≥2, D′=1) and pink signifying relatively weak LD (LOD ≥2, D′=1).
Abbreviations: LD, linkage disequilibrium; LOD, likelihood of odds; SNP, single nucleotide polymorphism; TRPM8, transient receptor potential cation channel subfamily M member 8.