Rural–Urban Differences in Mild Cognitive Impairment Among Patients with Chronic Obstructive Pulmonary Disease in ChengDu, China

Figures & data

Figure 1 Flowchart of subject recruitment for the study participants.

Table 1 Characteristics of Participants in Urban and Rural Areas

Variable	Total N=372	Percent (95% CI)	Urban N=190	Percent (95% CI)	Rural N=182	Percent (95% CI)	p-value (Urban vs Rural)
Sex							0.446
Male	244	65.6[60.7–70.4]	121	63.7[56.8–70.6]	123	67.6[60.7–74.4]
Female	128	34.4[29.6–39.3]	69	36.3[29.4–43.2]	59	32.4[25.6–39.3]
Age (year)							0.509
40–54	49	13.2[9.7–16.6]	26	13.7[8.8–18.6]	23	12.6[7.8–17.5]
55–70	111	29.8[25.2–34.5]	59	31.0[24.4–37.7]	52	28.6[21.9–35.2]
71+	212	57.0[51.9–62.0]	105	55.3[48.1–62.4]	107	58.8[51.6–66.0]
Education level							<0.001
Junior middle school or below	260	69.9[65.2–74.6]	86	45.3[38.1–52.4]	174	95.6[92.6–98.6]
High school or above	112	30.1[25.4–34.8]	104	54.7[47.6–61.9]	8	4.4[1.4–7.4]
Occupation							<0.001
Farm laborer	196	52.7[47.6–57.8]	23	12.1[7.4–16.8]	173	95.1[91.9–98.2]
Non-Farm laborer	176	47.3[42.2–52.4]	167	87.9[83.2–92.6]	9	4.9[1.8–8.1]
Marital status							0.886
Married	315	84.7[81.0–88.4]	160	84.2[79.0–9.4]	155	85.2[80.0–90.4]
Widowed/divorced/unmarried	57	15.3[11.6–19.0]	30	15.8[10.6–21.0]	27	14.8[9.6–20.0]
Living arrangement							0.718
Live alone	33	8.9[6.0–11.8]	18	9.5[5.3–13.7]	15	8.2[4.2–12.3]
Live with others	339	91.1[88.2–940]	172	90.5[86.3–94.7]	167	91.8[87.7–95.8]
Monthly household income (RMB)							<0.001
<5000	89	23.9[19.6–28.3]	20	10.5[6.1–14.9]	69	37.9[30.8–45.0]
≥5000	283	76.1[71.7–80.4]	170	89.5[85.1–93.9]	113	62.1[55.0–69.2]
Smoking status							0.004
Never smoker	190	51.0[46.0–56.2]	113	59.5[52.4–66.5]	77	42.3[35.1–49.6]
Former smoker	104	28.0[23.4–32.5]	45	23.7[17.6–29.8]	59	32.4[25.6–39.3]
Current smoker	78	21.0[16.8–25.1]	32	16.8[11.5–22.2]	46	25.3[18.9–31.6]
Drinking							0.727
NO	270	72.6[68.0–77.1]	136	71.6[65.1–78.1]	134	73.6[62.7–80.1]
YES	102	27.4[22.9–32.0]	54	28.4[21.9–34.9]	48	26.4[19.9–32.8]
Daily hours of sleep							0.612
<6	157	42.2[37.2–47.2]	78	41.1[34.0–48.1]	79	43.4[36.1–50.7]
6–8	174	46.8[41.7–51.9]	90	47.4[40.2–54.5]	84	46.2[38.8–53.5]
>8	41	11.0[7.8–14.2]	22	11.6[7.0–16.2]	19	10.4[6.0–14.9]
Decision makers in family							<0.001
NO	168	45.2[40.1–50.2]	59	31.1[24.4–37.7]	109	59.9[52.7–67.1]
YES	204	54.8[49.8–59.9]	131	68.9[62.3–75.6]	73	40.1[32.9–47.3]
Family history of dementia							0.485
NO	353	94.9[92.6–97.1]	182	95.8[92.9–98.7]	171	94.0[90.5–97.5]
YES	19	5.1[2.9–7.4]	8	4.2[1.3–7.1]	11	6.0[2.5–9.5]
Daily hours of entertainment							<0.001
0	145	39.0[34.0–44.0]	56	29.5[22.9–36.0]	89	48.9[41.6–56.2]
0–4	66	17.7[13.8–21.6]	27	14.2[9.2–19.2]	39	21.4[15.4–27.4]
>4	161	43.3[38.2–48.3]	107	56.3[49.2–63.4]	54	29.7[23.0–36.4]
Frequent shopping NO YES	168 204	45.2[40.1–50.2] 54.8[49.8–59.9]	58 132	30.5[23.9–37.1] 69.5[62.9–76.1]	110 72	60.4[53.3–67.6] 39.6[32.4–46.7]	<0.001
Comorbidity							0.001
No other chronic illness	209	56.2[51.1–61.2]	123	64.7[57.9–71.6]	86	47.3[39.9–54.6]
One and more other chronic condition	163	43.8[38.8–48.9]	67	35.3[28.4–42.1]	96	52.7[45.4–60.1]
Daily hours of exercise							<0.001
<1	113	30.4[25.7–35.1]	86	45.3[38.1–52.4]	27	14.8[9.6–20.0]
1–2	57	15.3[11.6–19.0]	24	12.6[7.9–17.4]	33	18.1[12.5–23.8]
>2	202	54.3[49.2–59.4]	80	42.1[35.0–49.2]	122	67.0[60.1–73.9]
Long-term home oxygen therapy							0.007
NO	206	55.4[50.3–60.5]	92	48.4[41.3–55.6]	114	62.6[55.5–69.7]
YES	166	44.6[39.5–49.7]	98	51.6[44.4–58.7]	68	37.4[30.3–44.5]
FEV1%pred							0.293
A	102	27.4[22.9–32.0]	54	28.4[21.9–34.9]	48	26.4[19.9–32.8]
B	177	47.6[42.5–52.7]	94	49.5[42.3–56.6]	83	45.6[38.3–52.9]
C+ D	93	25.0[20.6–29.4]	42	22.1[16.2–28.1]	51	28.0[21.4–34.6]
BMI							0.347
<18.5	27	7.2[4.6–9.9]	16	8.4[4.4–12.4]	11	6.0[2.5–9.5]
18.5–23.9	200	53.8[48.7–58.9]	104	54.7[47.6–61.9]	96	52.7[45.4–60.1]
24–27.9	116	31.2[26.5–35.9]	55	28.9[22.4–35.5]	61	33.5[26.6–40.4]
≥28	29	7.8[5.1–10.5]	15	7.9[4.0–11.8]	14	7.6[3.8–11.6]
FVC(L), M (SD)	2.43±0.85		2.49±0.84		2.37±0.86		0.169
FEV1(L), M (SD)	1.50±0.61		1.57±0.58		1.43±0.63		0.009
FEVI/FVC(%), M (SD)	59.37±9.70		60.85±8.89		57.84±10.39		0.004

Notes: FEV1%pred: A(GOLD1):FEV1%pred≥80%;B(GOLD2): 50%≤FEV1%pred<80%; C(GOLD 3):30%≤FEV1%pred<50%; D(GOLD 4): FEV1%pred<30%.

Table 2 Prevalence of MCI Among COPD Patients by Variables in Urban and Rural Areas

Variable	Total Percent(95% CI) 56.5[51.4–61.5]	p-value	Urban Percent(95% CI) 47.9[40.7–55.1]	p-value	Rural Percent (95% CI) 65.4[58.4–72.4]	p-value
Residence		0.001
Urban	47.9[40.7–55.1]
Rural	65.4[58.4–72.4]
Sex		0.124		0.370		0.248
Male	59.4[53.2–65.6]		50.4[41.4–59.5]		68.3[60.0–76.6]
Female	50.8[42.0–59.6]		43.5[31.5–55.5]		59.3[46.4–72.2]
Age (year)		<0.001		<0.001		<0.001
40–54	10.2[1.4–19.0]		7.7[3.3–18.7]		13.0[1.8–27.9]
55–70	18.9[11.5–26.3]		5.1[0.7–10.9]		34.6[21.2–48.0]
71+	86.8[82.2–91.4]		81.9[74.4–89.4]		91.6[86.2–96.9]
Education level		<0.001		<0.001		0.001
Junior middle school or below	68.8[63.2–74.5]		70.9[61.1–80.7]		67.8[60.8–74.8]
High school or above	27.7[19.3–36.1]		28.8[20.0–37.7]		12.5[17.1–42.1]
Occupation		<0.001		<0.001		0.066
Farm laborer	68.9[62.3–75.4]		82.6[65.8–99.4]		67.1[60.0–74.1]
Non-Farm laborer	42.6[35.2–50.0]		43.1[35.5–50.7]		33.3[5.1–71.8]
Marital status		0.959		0.555		0.514
Married	56.5[51.0–62.0]		46.9[39.1–54.7]		66.5[58.9–74.0]
Widowed/divorced/unmarried	56.1[42.9–69.4]		53.3[34.4–72.3]		59.3[39.5–79.1]
Living arrangement		0.362		0.421		0.778
Live alone	48.5[30.5–66.5]		38.9[13.9–63.8]		60.0[31.9–88.1]
Live with others	57.2[51.9–62.5]		49.4[41.8–57.0]		65.9[58.6–73.1]
Monthly household income (RMB)		<0.001		0.502		<0.001
<5000	83.1[75.2–91.1]		55.0[31.1–78.9]		91.3[84.5–98.1]
≥5000	48.1[42.2–53.9]		47.1[39.5–54.6]		49.6[40.2–58.9]
Smoking status		<0.001		<0.001		<0.001
Never smoker	39.5[32.5–46.5]		34.5[25.6–43.4]		46.8[35.4–58.2]
Former smoker	75.0[66.5–83.5]		66.7[52.3–81.0]		81.4[71.1–91.6]
Current smoker	73.1[63.0–83.1]		68.8[51.8–85.7]		76.1[63.3–88.9]
Drinking		0.907		0.714		0.724
NO	56.7[50.7–62.6]		47.1[38.6–55.6]		66.4[58.3–74.5]
YES	55.9[46.1–65.7]		50.0[36.2–63.8]		62.5[48.3–76.7]
Daily hours of sleep		<0.001		<0.001		<0.001
<6	77.1[70.4–83.7]		69.2[58.8–79.7]		84.8[76.7–92.9]
6–8	42.0[34.5–49.4]		27.8[18.3–37.2]		57.1[46.3–67.9]
>8	39.0[23.4–54.6]		54.5[31.9–77.1]		21.1[0.9–41.2]
Decision makers in family		<0.001		<0.001		<0.001
NO	93.5[89.7–92.7]		93.2[86.6–99.8]		93.6[88.9–98.3]
YES	26.0[19.9–32.0]		27.5[19.7–35.2]		23.3[13.4–33.2]
Family history of dementia		0.346		0.903		0.335
NO	55.8[50.6–61.0]		47.8[40.5–55.1]		64.3[57.1–71.6]
YES	68.4[45.4–91.4]		50.0[5.3–94.7]		81.8[54.6–109.0]
Frequent Shopping		<0.001		<0.001		<0.001
NO	86.3[81.1–91.6]		79.3[68.6–90.1]		90.0[84.3–95.7]
YES	31.9[25.4–38.3]		34.1[25.9–42.3]		27.8[17.2–38.4]
Comorbidity		<0.001		<0.001		<0.001
No other chronic illness	39.7[33.0–46.4]		37.4[28.7–46.1]		43.0[32.3–53.7]
One and more other chronic condition	77.9[71.5–84.4]		67.2[55.6–78.7]		85.4[78.2–92.6]
Daily hours of exercise		<0.001		<0.001		<0.001
<1	70.8[62.3–79.3]		67.4[57.3–77.5]		81.5[65.8–97.1]
1–2	77.2[66.0–88.4]		58.3[37.1–79.6]		90.9[80.6–101.3]
>2	42.6[35.7–49.5]		23.8[14.2–33.3]		54.9[46.0–63.9]
Long-term home oxygen therapy		<0.001		0.985		<0.001
NO	66.0[59.5–72.5]		47.8[37.4–58.2]		80.7[73.3–88.1]
YES	44.6[36.9–52.2]		48.0[37.9–58.0]		39.7[27.8–51.6]
FEV1%pred		<0.001		<0.001		<0.001
A	25.5[16.9–34.1]		31.5[18.7–44.3]		18.8[7.3–30.2]
B	61.0[53.8–68.3]		44.7[34.4–54.9]		79.5[70.7–88.4]
C+ D	81.7[73.7–89.7]		76.2[62.8–89.6]		80.0[69.1–90.9]
BMI		0.222		0.141		0.631
<18.5	77.8[61.0–94.5]		75.0[51.2–98.8]		81.8[54.6–109.0]
18.5–23.9	55.0[48.0–62.0]		46.2[36.4–55.9]		64.6[54.8–74.3]
24–27.9	54.3[45.1–63.5]		45.5[31.9–59.0]		62.3[49.8–74.8]
≥28	55.2[35.9–74.4]		40.0[11.9–68.1]		71.4[44.4–98.5]
FVC(L), M (SD)	2.29±0.77	0.002	2.43±0.76	0.635	2.19±0.76	<0.001
FEV1(L), M (SD)	1.36±0.55	<0.001	1.51±0.54	0.281	1.25±0.76	<0.001
FEVI/FVC(%), M (SD)	56.74±10.60	<0.001	59.02±10.40	0.126	54.99±10.46	<0.001

Notes: FEV1%pred: A(GOLD1):FEV1%pred≥80%;B(GOLD2): 50%≤FEV1%pred<80%; C(GOLD 3):30%≤FEV1%pred<50%; D(GOLD 4): FEV1%pred<30%.

Table 3 The Variables Independently Associated with MCI Both in Urban and Rural Areas

Variable	Urban		Rural
	UOR (95% CI)	AOR(95% CI)	UOR (95% CI)	AOR(95% CI)
Age (year)
40–54	1.00	1.00	1.00	1.00
55–70	0.643(0.101–4.097)	0.051(0.002–1.392)	3.529(0.923–13.496)	3.046(0.402–23.074)
71+	54.316***(11.812–249.754)	94.477***(7.587–1176.422)	72.593***(18.039–292.129)	22.020*(2.112–229.565)
Monthly household income (RMB)
<5000	1.00	1.00	1.00	1.00
≥5000	0.727(0.287–1.845)	12.482*(1.476–105.563)	0.094***(0.037–0.234)	0.046***(0.010–0.215)
Smoking status
Never smoker	1.00	1.00	1.00	1.00
Former smoker	3.795***(1.827–7.884)	11.583*(1.769–75.866)	4.970***(2.248–10.989)	5.216*(1.323–20.563)
Current smoker	4.174**(1.798–9.690)	5.285(0.984–28.384)	3.624**(1.609–8.162)	2.599(0.597–11.309)
Daily hours of sleep
<6	1.00	1.00	1.00	1.00
6–8	0.171***(0.088–0.333)	0.090**(0.017–0.471)	0.239***(0.113–0.506)	0.561(0.148–2.122)
>8	0.533(0.203–1.403)	1.809(0.098–33.444)	0.048***(0.014–0.169)	0.627(0.094–4.166)
Decision makers in family
NO	1.00	1.00	1.00	1.00
YES	0.028***(0.009–0.082)	0.032**(0.004–0.224)	0.021***(0.008–0.053)	0.175*(0.036–0.854)
Frequent shopping
NO	1.00	1.00	1.00	1.00
YES	0.135***(0.065–0.280)	0.107*(0.020–0.565)	0.043***(0.019–0.096)	0.348(0.098–1.238)
Daily hours of exercise
<1	1.00	1.00	1.00	1.00
1–2	0.676(0.267–1.710)	0.304(0.041–2.229)	2.273(0.490–10.532)	8.627(0.590–126.070)
>2	0.150***(0.076–0.298)	0.037***(0.007–0.191)	0.277*(0.098–0.779)	2.313(0.322–16.631)
Long-term home oxygen therapy
NO	1.00	1.00	1.00	1.00
YES	1.005 (0.569–1.777)	0.804(0.221–2.922)	0.157***(0.080–0.309)	0.133**(0.041–0.436)
FEV1%pred
A	1.00	1.00	1.00	1.00
B	1.758(0.870–3.553)	7.281*(1.246–42.530)	16.824***(6.824–41.368)	2.634(0.690–10.126)
C+ D	6.965**8(2.794–17.358)	8.885(0.827–95.441)	27.238***(9.271–80.022)	2.389(0.351–16.247)

Notes: 1.00:Reference; UOR: Unadjusted Odds Ratio; AOR: Adjusted Odds Ratio; CI:Confidence Interval. AOR: adjusted for significant variables from univariate analyses, and we also excluded significant variables with VIF greater than 5. In this study, we adjusted for age, education level, occupation, monthly household income, smoking status, daily hours of sleep, frequent shopping, comorbidity, daily hours of exercise, long-term home oxygen therapy, and FEV1%pred. ***P ≤0.001; **P≤0.005; *P≤0.05. FEV1%pred: A(GOLD1):FEV1%pred≥80%;B(GOLD2): 50%≤FEV1%pred<80%; C(GOLD 3):30%≤FEV1%pred<50%; D(GOLD 4): FEV1%pred<30%.