3.1 Participant characteristics
In this study, a total of 24739 participants were included, with participant characteristics presented in Table 1. The participants were divided into two groups: a group without depressive symptoms and the other group with depressive symptoms. After weighting, there were 12315 (49.12%) males and 12424 (50.88%) females. The participants' ages were distributed as follows: 10417 (44.97%) individuals aged 20 - 44, 8656 (37.12%) individuals aged 45 - 64, and the remaining aged over 64. Meantime, the race composition included 5166 (10.60%) non-Hispanic whites, 3584 (8.10%) non-Hispanic blacks, 5114 (12.76%) Mexican Americans, and 10875 (68.54%) participants of other races. There were 2499 (44.95%) smokers and 11146 (44.76%) drinkers among the participants. The prevalence of diagnoses included 8981 (32.06%) cases of hypertension, 3182 (9.65%) cases of diabetes, 2647 (8.48%) cases of coronary heart disease, and 2425 (10.32%) cases of tumors.
Table 1 Baseline table exploring the relationship between CIAD and depressive symptoms
Variable
|
Total
|
Depressive symptoms
|
P for
interaction
|
No
|
Yes
|
Age, n (%)
|
|
|
|
< 0.0001
|
20 - 44 years
|
10417(44.97)
|
9514(45.00)
|
903(44.58)
|
|
45 - 64 years
|
8656(37.12)
|
7711(36.59)
|
945(43.10)
|
|
≥ 65 years
|
5666(17.91)
|
5297(18.41)
|
369(12.32)
|
|
Sex, n (%)
|
|
|
|
< 0.0001
|
Female
|
12424(50.88)
|
11011(49.81)
|
1413(62.78)
|
|
Male
|
12315(49.12)
|
11511(50.19)
|
804(37.22)
|
|
Marital status, n (%)
|
|
|
|
< 0.0001
|
Married/Living with Partner
|
14730(62.26)
|
13754(63.73)
|
976(46.00)
|
|
Widowed/Divorced/Separated
|
4552(19.21)
|
4076(18.83)
|
476(23.48)
|
|
Never married
|
5457(18.52)
|
4692(17.44)
|
765(30.52)
|
|
Race, n (%)
|
|
|
|
0.01
|
Non-Hispanic White
|
5166(10.60)
|
4708(10.42)
|
458(12.58)
|
|
Non-Hispanic Black
|
3584( 8.10)
|
3268(8.11)
|
316(7.96)
|
|
Mexican American
|
5114(12.76)
|
4661(12.56)
|
453(15.00)
|
|
Other races
|
10875(68.54)
|
9885(68.91)
|
990(64.47)
|
|
Educational level, n (%)
|
|
|
|
< 0.0001
|
< High school
|
5665(23.04)
|
5128(22.66)
|
537(27.22)
|
|
High school diploma
|
5548(14.18)
|
4795(13.35)
|
753(23.41)
|
|
> High school
|
13526(62.78)
|
12599(63.99)
|
927(49.36)
|
|
PIR, n (%)
|
|
|
|
< 0.0001
|
< 1.3
|
7731 (21.70)
|
6559(19.84)
|
1172(42.26)
|
|
1.3 - 3.5
|
9349 (34.80)
|
8610(34.70)
|
739(35.94)
|
|
> 3.5
|
7659 (43.51)
|
7353(45.47)
|
306(21.80)
|
|
Insurance, n (%)
|
|
|
|
< 0.0001
|
No
|
5200 (17.14)
|
4627(16.54)
|
573(23.79)
|
|
Yes
|
19539 (82.86)
|
17895(83.46)
|
1644(76.21)
|
|
Drinking status, n (%)
|
|
|
|
0.01
|
No
|
3335 (10.18)
|
3079(10.35)
|
256( 8.32)
|
|
Yes
|
21404 (89.82)
|
19443(89.65)
|
1961(91.68)
|
|
Smoking status, n (%)
|
|
|
|
< 0.0001
|
Former
|
6020 (24.79)
|
5530(25.12)
|
490(21.22)
|
|
Never
|
13593 (55.24)
|
12711(56.75)
|
882(38.47)
|
|
Now
|
5126 (19.97)
|
4281(18.13)
|
845(40.31)
|
|
BMI, kg/m2, n (%)
|
|
|
|
< 0.0001
|
< 25
|
6977 (29.28)
|
6448(29.62)
|
529(25.54)
|
|
25 - 30
|
8092 (32.69)
|
7513(33.26)
|
579(26.39)
|
|
> 30
|
9670 (38.03)
|
8561(37.12)
|
1109(48.07)
|
|
Hypertension, n (%)
|
|
|
|
< 0.0001
|
No
|
15758 (67.94)
|
14578(68.91)
|
1180(57.22)
|
|
Yes
|
8981 (32.06)
|
7944(31.09)
|
1037(42.78)
|
|
Diabetes mellitus, n (%)
|
|
|
|
< 0.0001
|
Borderline
|
579 ( 2.00)
|
516(1.93)
|
63(2.69)
|
|
No
|
20978 (88.36)
|
19254(88.91)
|
1724(82.26)
|
|
Yes
|
3182 ( 9.65)
|
2752( 9.16)
|
430(15.05)
|
|
CVD, n (%)
|
|
|
|
< 0.0001
|
No
|
22092 (91.52)
|
20304(92.16)
|
1788(84.34)
|
|
Yes
|
2647 ( 8.48)
|
2218( 7.84)
|
429(15.66)
|
|
HEI-2015, n (%)
|
|
|
|
< 0.0001
|
Q1
|
6185 (24.53)
|
5459(23.77)
|
726(32.93)
|
|
Q2
|
6184 (24.72)
|
5593(24.60)
|
591(26.11)
|
|
Q3
|
6185 (25.08)
|
5651(25.13)
|
534(24.57)
|
|
Q4
|
6185 (25.66)
|
5819(26.50)
|
366(16.38)
|
|
Daily energy intake, n (%)
|
|
|
|
< 0.0001
|
Q1
|
6188(22.51)
|
5514(21.92)
|
674(29.07)
|
|
Q2
|
6185(24.92)
|
5634(24.99)
|
551(24.25)
|
|
Q3
|
6185(26.36)
|
5699(26.73)
|
486(22.26)
|
|
Q4
|
6181(26.20)
|
5675(26.36)
|
506(24.42)
|
|
Tumor, n (%)
|
|
|
|
0.53
|
No
|
22314(89.68)
|
20344(89.73)
|
1970(89.08)
|
|
Yes
|
2425(10.32)
|
2178(10.27)
|
247(10.92)
|
|
CIAD, n (%)
|
|
|
|
< 0.0001
|
NO
|
19752(79.48)
|
18298(80.71)
|
1454(65.81)
|
|
Yes
|
4987(20.52)
|
4224(19.29)
|
763(34.19)
|
|
The p-value was calculated by weighted linear regression model. % forcategorical variables: the p-value was calculated by a weighted chi-square test.
HEI-2015 Q1: 0 - 40.72; Q2: 40.72 - 50.22; Q3: 50.22 - 60.19; Q4: 60.19 - 96.00;
Daily energy intake (Kal): Q1: 0 – 1437.00; Q2: 1437.00 – 1944.00; Q3: 1944.00 – 2602.00; Q4: 2602.00 – 13687.00.
Abbreviations: PIR, poverty income ratio; BMI, body mass index; CVD , Cardiovascular Disease; HEI-2015:Healthy Eating Index 2015; CIAD, Chronic inflammatory airway diseases.
3.2 Association between CIAD and depressive symptoms
In Table 2, participants were grouped based on the presence or absence of CIAD, without CIAD as the reference. Weighted logistic regression showed that in the unadjusted crude model, patients with CIAD had a higher risk of co-occurring depressive symptoms (OR = 2.17, 95% CI: 1.88 - 2.51). In model 1, after adjusting for age, sex, race, education level, and marital status, the relationship between CIAD and depressive symptoms remained robust (OR = 2.04, 95% CI: 1.75 - 2.38). In model 2, after adjusting for smoking status, drinking status, insurance, and PIR on the basis of model 1, similar results were obtained (OR = 1.76, 95% CI: 1.51 - 2.06). In model 3, after further adjusting for BMI, hypertension, CVD, tumor, diabetes mellitus, daily energy intake, and HEI-2015 based on model 2, the similar association remained robust (OR = 1.58, 95% CI: 1.35 - 1.86).
Table 2. Different models of the association between CIAD and depressive symptoms.
|
Crude model
|
Model 1
|
Model 2
|
Model 3
|
OR (95% CI)
|
OR (95% CI)
|
OR (95% CI)
|
OR (95% CI)
|
CIAD
|
|
NO
|
Reference
|
Reference
|
Reference
|
Reference
|
Yes
|
2.17(1.88,2.51)
|
2.04(1.75,2.38)
|
1.76(1.51,2.06)
|
1.58(1.35,1.86)
|
P
|
< 0.0001
|
< 0.0001
|
< 0.0001
|
< 0.0001
|
Data were present as odds ratio (OR) and 95% confidence interval (CI).
Crude model, no covariate was adjusted.
Model 1, Sex, Age, race, education level, marital status were adjusted.
Model 2, Sex, Age, race, education level, marital status, smoking status, drinking status, insurance, PIR were adjusted.
Model3, Sex, Age, race, education level, marital status, smoking status, drinking status, insurance, PIR, BMI, hypertension, CVD, tumor, diabetes mellitus, daily energy intake, HEI-2015 were adjusted.
Abbreviations:95% CI; 95% confidence interval; OR, odds ratio; CIAD, Chronic inflammatory airway diseases.
3.3 General information on LTPA and depressive symptoms in CIAD patients
Building upon the aforementioned study population, we further analyzed the association between depressive symptoms and LTPA in 4987 patients with CIAD. Due to a lack of LTPA data, the 27 individuals were excluded, so the remaining 4960 patients for further analysis. General information on LTPA and depressive symptoms in CIAD patients as shown in Table 3. After weighting, there were 2252 (43.40%) male patients and 2,708 (56.60%) female patients. Participants were grouped by age as follows: 1972 (42.54%) individuals aged 20 - 44, 1786 (38.03%) individuals aged 45 - 64, and the remaining individuals were over 64 years old. Among the participants, there were 1100 (11.23%) non-Hispanic white individuals, 407 (4.92%) non-Hispanic black individuals, 866 (11.10%) Mexican-American individuals, and 2587 (72.75%) individuals of other races. Meantime, there were 2808 (55.23%) smokers and 4,433 (91.72%) drinkers. Diagnoses included hypertension in 2167 (37.82%) cases, diabetes mellitus in 840 (13.00%) cases, CVD in 843 (13.58%) cases, and tumor in 619 (13.15%) cases.
Table 3 Baseline table exploring the relationship between LTPA and depressive symptoms in patients with CIAD
Variable
|
Total
|
Depressive symptoms
|
P for
interaction
|
No
|
Yes
|
Age, n (%)
|
|
|
|
0.002
|
20 - 44 years
|
1972(42.54)
|
1689(42.76)
|
283(41.10)
|
|
45 - 64 years
|
1786(38.03)
|
1447(37.06)
|
339(44.08)
|
|
≥65 years
|
1202(19.44)
|
1067(20.17)
|
135(14.82)
|
|
Sex, n (%)
|
|
|
|
0.01
|
Female
|
2708(56.60)
|
2219(55.40)
|
489(64.16)
|
|
Male
|
2252(43.40)
|
1984(44.60)
|
268(35.84)
|
|
Marital status, n (%)
|
|
|
|
< 0.0001
|
Married/Living with Partner
|
2675(58.21)
|
2351(60.09)
|
324(46.43)
|
|
Widowed/Divorced/Separated
|
963(20.32)
|
823(20.44)
|
140(19.52)
|
|
Never married
|
1322(21.47)
|
1029(19.46)
|
293(34.05)
|
|
Race, n (%)
|
|
|
|
0.19
|
Non-Hispanic White
|
1100(11.23)
|
955(11.09)
|
145(12.11)
|
|
Non-Hispanic Black
|
407( 4.92)
|
348(4.87)
|
59(5.22)
|
|
Mexican American
|
866(11.10)
|
711(10.77)
|
155(13.18)
|
|
other
|
2587(72.75)
|
2189(73.27)
|
398(69.50)
|
|
Educational level, n (%)
|
|
|
|
< 0.0001
|
< high school
|
1168(23.40)
|
986(22.74)
|
182(27.57)
|
|
High school diploma
|
1108(15.03)
|
850(13.10)
|
258(27.13)
|
|
> high school
|
2684(61.57)
|
2367(64.16)
|
317(45.30)
|
|
PIR, n (%)
|
|
|
|
< 0.0001
|
< 1.3
|
1808(26.45)
|
1373(22.83)
|
435(49.13)
|
|
1.3 - 3.5
|
1779(34.24)
|
1545(34.60)
|
234(31.98)
|
|
> 3.5
|
1373(39.32)
|
1285(42.58)
|
88(18.88)
|
|
Insurance, n (%)
|
|
|
|
0.06
|
No
|
883(15.11)
|
731(14.58)
|
152(18.38)
|
|
Yes
|
4077(84.89)
|
3472(85.42)
|
605(81.62)
|
|
Drinking status, n (%)
|
|
|
|
0.69
|
No
|
527( 8.28)
|
441(8.34)
|
86(7.88)
|
|
Yes
|
4433(91.72)
|
3762(91.66)
|
671(92.12)
|
|
Smoking status, n (%)
|
|
|
|
< 0.0001
|
Former
|
1400(28.21)
|
1222(28.70)
|
178(25.17)
|
|
Never
|
2152(44.77)
|
1931(47.92)
|
221(25.01)
|
|
Now
|
1408(27.02)
|
1050(23.39)
|
358(49.81)
|
|
BMI, kg/m2, n (%)
|
|
|
|
< 0.001
|
< 25
|
1251(27.05)
|
1089(27.44)
|
162(24.63)
|
|
25 - 30
|
1456(29.24)
|
1282(30.52)
|
174(21.19)
|
|
> 30
|
2253(43.71)
|
1832(42.04)
|
421(54.18)
|
|
Hypertension, n (%)
|
|
|
|
< 0.0001
|
No
|
2793(62.18)
|
2461(64.20)
|
332(49.51)
|
|
Yes
|
2167(37.82)
|
1742(35.80)
|
425(50.49)
|
|
Diabetes mellitus, n (%)
|
|
|
|
< 0.0001
|
Borderline
|
133( 2.34)
|
112(2.22)
|
21(3.08)
|
|
No
|
3987(84.66)
|
3437(86.04)
|
550(75.98)
|
|
Yes
|
840(13.00)
|
654(11.74)
|
186(20.94)
|
|
CVD, n (%)
|
|
|
|
< 0.0001
|
No
|
4117(86.42)
|
3567(88.30)
|
550(74.60)
|
|
Yes
|
843(13.58)
|
636(11.70)
|
207(25.40)
|
|
HEI-2015, n (%)
|
|
|
|
< 0.0001
|
Q1
|
1407(27.57)
|
1153(26.72)
|
254(32.93)
|
|
Q2
|
1232(24.48)
|
1015(23.61)
|
217(29.94)
|
|
Q3
|
1204(24.11)
|
1042(24.57)
|
162(21.23)
|
|
Q4
|
1117(23.84)
|
993(25.11)
|
124(15.90)
|
|
Daily energy intake, n (%)
|
|
|
|
0.11
|
Q1
|
1341(24.17)
|
1094(23.43)
|
247(28.93)
|
|
Q2
|
1262(25.28)
|
1072(25.39)
|
190(24.71)
|
|
Q3
|
1124(24.60)
|
972(25.06)
|
152(21.84)
|
|
Q4
|
1229(25.88)
|
1062(26.12)
|
167(24.52)
|
|
Tumor, n (%)
|
|
|
|
0.91
|
No
|
4341(86.85)
|
3685(86.89)
|
656(86.64)
|
|
Yes
|
619(13.15)
|
518(13.11)
|
101(13.36)
|
|
LTPA, n (%)
|
|
|
|
< 0.0001
|
No
|
2741(48.97)
|
2176(45.49)
|
565(70.82)
|
|
Yes
|
2219(51.03)
|
2027(54.51)
|
192(29.18)
|
|
The p-value was calculated by weighted linear regression model. % forcategorical variables: the p-value was calculated by a weighted chi-square test.
HEI-2015 Q1: 0 - 40.72; Q2: 40.72 - 50.22; Q3: 50.22 - 60.19; Q4: 60.19 - 96.00;
Daily energy intake (Kal): Q1: 0 - 1437; Q2: 1437 - 1944; Q3: 1944 - 2602; Q4: 2602 – 13687.
Abbreviations: PIR, poverty income ratio; BMI, body mass index; CVD , Cardiovascular Disease; HEI-2015:Healthy Eating Index 2015; LTPA, leisure-time physical activity
3.4 Association between LTPA and depressive symptoms in CIAD patients
In Table 4, we grouped participants based on the presence or absence of LTPA, with the absence of LTPA as the reference. Weighted logistic regression showed that in the unadjusted crude model, LTPA could reduce the risk of depressive symptoms among patients with CIAD (OR = 0.34, 95% CI: 0.26 - 0.45). In model 1, after adjusting for age, gender, race, education level, and marital status, LTPA remained associated with a reduced risk of depressive symptoms (OR = 0.38, 95% CI: 0.28 - 0.51). In model 2, further adjustments were made for smoking status, drinking status, insurance, and PIR based on model 1, and the negative association between LTPA and depressive symptoms in CIAD patients persisted (OR = 0.46, 95% CI: 0.34 - 0.63). In model 3, additional adjustments were made for BMI, hypertension, CVD, tumor, diabetes mellitus, daily energy intake, and HEI-2015 on top of model 2, and the association still remained (OR = 0.51, 95% CI: 0.37 - 0.69).
Table 4. Different models of the association between LTPA and depressive symptoms in patients with CIAD.
|
Crude model
|
Model 1
|
Model 2
|
Model 3
|
OR (95% CI)
|
OR (95% CI)
|
OR (95% CI)
|
OR (95% CI)
|
LTPA
|
|
NO
|
Reference
|
Reference
|
Reference
|
Reference
|
Yes
|
0.34(0.26,0.45)
|
0.38(0.28,0.51)
|
0.46(0.34,0.63)
|
0.51(0.37,0.69)
|
P
|
< 0.0001
|
< 0.0001
|
< 0.0001
|
< 0.0001
|
Data were present as odds ratio (OR) and 95% confidence interval (CI).
Crude model, no covariate was adjusted.
Model 1, Sex, Age, race, education level, marital status were adjusted.
Model 2, Sex, Age, race, education level, marital status, smoking status, drinking status, insurance, PIR were adjusted.
Model3, Sex, Age, race, education level, marital status, smoking status, drinking status, insurance, PIR, BMI, hypertension, CVD, tumor, diabetes mellitus, daily energy intake, HEI-2015 were adjusted.
Abbreviations:95% CI; 95% confidence interval; OR, odds ratio; LTPA, leisure-time physical activity.
3.5 Stratified analysis
As shown in Table 5, compared to CIAD patients without LTPA, the prevalence of depressive symptoms among patients with LTPA remains fairly consistent across various subgroups based on age, sex, race, education level, and marital status, with no significant interactions observed between the stratified variables (P > 0.05).
Table 5 Stratified analysis of the relationship between LTPA and depressive symptoms in patients with CIAD
Subgroups
|
Depressive symptoms
|
p
|
P for
interaction
|
No
|
Yes
|
Age
|
|
|
|
0.08
|
≥65 years
|
1
|
0.39(0.25,0.59)
|
<0.0001
|
|
45 - 64 years
|
1
|
0.68(0.33, 1.43)
|
0.3
|
|
20 - 44 years
|
1
|
0.27(0.20,0.38)
|
<0.0001
|
|
Sex
|
|
|
|
0.67
|
Female
|
1
|
0.42(0.30,0.58)
|
<0.0001
|
|
Male
|
1
|
0.38(0.23,0.62)
|
<0.001
|
|
Race
|
|
|
|
0.73
|
Non-Hispanic White
|
1
|
0.38(0.27,0.54)
|
<0.0001
|
|
Non-Hispanic Black
|
1
|
0.51(0.31,0.85)
|
0.01
|
|
Mexican American
|
1
|
0.31(0.11,0.85)
|
0.02
|
|
other
|
1
|
0.38(0.21,0.67)
|
0.001
|
|
Educational level
|
|
|
|
0.12
|
< high school
|
1
|
0.73(0.44,1.20)
|
0.21
|
|
High school diploma
|
1
|
0.32(0.18,0.57)
|
<0.001
|
|
> high school
|
1
|
0.44(0.29,0.66)
|
<0.001
|
|
Marital status
|
|
|
|
0.49
|
Married/Living with Partner
|
1
|
0.42(0.27,0.65)
|
<0.001
|
|
Widowed/Divorced/Separated
|
1
|
0.40(0.27, 0.60)
|
<0.0001
|
|
Never married
|
1
|
0.31(0.18,0.52)
|
<0.0001
|
|
Through RCS plot analysis, the relationship between LTPA and depressive symptoms in CIAD patients was illustrated (Figure 2). The risk of depressive symptoms (non-linear P = 0.001) is approximately L-shaped in relation to LTPA duration, with a threshold of 12h/week. We found that when duration of LTPA is ≤ 12h/week, as the time increases, the risk of depressive symptoms decreases. However, when duration exceeds 12h/week, depressive symptoms will no longer benefit.