Depression, diabetes and immigration status: a retrospective cohort study using the Canadian Longitudinal Study on Aging

Doaa Farid; Patricia Li; Deborah Da Costa; Waqqas Afif; Jason Szabo; Kaberi Dasgupta; Elham Rahme

doi:10.9778/cmajo.20210019

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Figure 1:
Flow chart of study cohorts. Note: CLSA = Canadian Longitudinal Study on Aging.

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Table 1:

Baseline characteristics of Cohort 1 individuals with and without baseline diabetes by immigration status

Characteristic	Immigrant		Nonimmigrant

	No. (%) of participants with diabetes n = 616	No. (%) of participants without diabetes n = 3150	No. (%) of participants with diabetes n = 2639	No. (%) of participants without diabetes n = 14 318
Age, yr

45–60	141 (22.9)	1173 (37.2)	893 (33.8)	7050 (49.2)

61–70	236 (38.3)	1050 (33.3)	969 (36.7)	4224 (29.5)

71–85	239 (38.8)	927 (29.4)	777 (29.4)	3044 (21.3)

Sex

Male	408 (66.2)	1743 (55.3)	1551 (58.8)	7167 (50.1)

Female	208 (33.8)	1407 (44.7)	1088 (41.2)	7151 (49.9)

Marital status

Single	27 (4.4)	149 (4.7)	234 (8.9)	1176 (8.2)

Married	455 (73.9)	2405 (76.3)	1834 (69.5)	10407 (72.7)

Widowed, divorced or separated	134 (21.8)	595 (18.9)	571 (21.6)	2731 (19.1)

Missing	–	1 (0.0)	–	4 (0.0)

Language most spoken at home

French	31 (5.0)	205 (6.5)	541 (20.5)	3171 (22.1)

English	492 (79.9)	2597 (82.4)	2092 (79.3)	11114 (77.6)

Other	55 (8.9)	254 (8.1)	3 (0.1)	17 (0.2)

Missing	38 (6.2)	94 (3.0)	3 (0.1)	16 (0.1)

Ethnic or racial background

White	464 (75.3)	2640 (83.8)	2596 (98.4)	14166 (98.9)

Black	36 (5.8)	89 (2.8)	8 (0.3)	19 (0.1)

South Asian	50 (8.1)	122 (3.9)	0 (0.0)	6 (0.0)

Chinese	24 (3.9)	107 (3.4)	8 (0.3)	37 (0.3)

Other	42 (6.8)	188 (6.0)	25 (0.9)	80 (0.6)

Missing	–	4 (0.1)	2 (0.1)	10 (0.1)

Years since arrival to Canada

< 20	42 (6.8)	396 (12.6)	–	–

20–40	162 (26.3)	781 (24.8)	–	–

> 40	412 (66.9)	1973 (62.6)	–	–

Total household income, $

< 20 000	29 (4.7)	82 (2.6)	140 (5.3)	432 (3.0)

20 000–50 000	141 (22.9)	589 (18.7)	641 (24.3)	2435 (17.0)

50 000–100 000	245 (39.8)	1076 (34.2)	927 (35.1)	4786 (33.4)

> 100 000	163 (26.5)	1180 (37.5)	779 (29.5)	5855 (40.9)

Missing	38 (6.1)	223 (7.0)	152 (5.8)	810 (5.7)

Working status

Employed	158 (25.6)	1333 (42.3)	826 (31.3)	6368 (44.5)

Unemployed	29 (4.7)	111 (3.5)	72 (2.7)	468 (3.3)

Retired	429 (69.6)	1699 (54.0)	1732 (65.6)	7453 (52.1)

Missing	–	7 (0.2)	9 (0.3)	29 (0.2)

Education level

Less than secondary school	20 (3.2)	77 (2.4)	188 (7.1)	590 (4.1)

Secondary school	51 (8.3)	195 (6.2)	316 (12.0)	1275 (8.9)

Postsecondary degree or diploma	541 (87.8)	2870 (91.1)	2134 (80.9)	12436 (86.9)

Missing	4 (0.6)	8 (0.3)	1 (0.0)	17 (0.1)

Place of residence^*

Rural	58 (9.4)	310 (9.8)	365 (13.8)	1849 (12.9)

Urban	551 (89.4)	2799 (88.9)	2239 (84.8)	12303 (85.9)

Missing	7 (1.1)	41 (1.3)	35 (1.4)	166 (1.2)

Province

Quebec	65 (10.6)	365 (11.6)	536 (20.3)	3199 (22.3)

British Columbia	189 (30.7)	996 (31.6)	538 (20.4)	2736 (19.1)

Ontario	169 (27.4)	869 (27.6)	551 (20.9)	2920 (20.4)

Other^†	193 (31.3)	920 (29.2)	1014 (38.4)	5463 (38.2)

Medical conditions^‡

Living with pain	226 (36.7)	944 (30.0)	1055 (40.0)	4260 (29.8)

Bowel disorders	41 (6.7)	227 (7.2)	224 (8.5)	1135 (7.9)

Arthritis	16 (2.6)	83 (2.6)	109 (4.1)	355 (2.5)

Heart disease	370 (60.1)	1007 (32.0)	1552 (58.8)	4353 (30.4)

Kidney disease	36 (5.8)	66 (2.1)	111 (4.2)	292 (2.0)

Stroke	11 (1.8)	36 (1.1)	65 (2.5)	157 (1.1)

Cancer	95 (15.4)	475 (15.1)	465 (17.6)	2005 (14.0)

Hypertension	355 (57.6)	1081 (34.3)	1530 (58.0)	4851 (33.9)

Anxiety disorder	17 (2.8)	109 (3.5)	137 (5.2)	606 (4.2)

Alcohol consumption

Never	92 (14.9)	309 (9.8)	340 (12.9)	1209 (8.4)

About once a month	141 (22.9)	514 (16.3)	608 (23.0)	2255 (15.7)

2–4 times a month	115 (18.7)	576 (18.3)	588 (22.3)	3160 (22.1)

> 2 times a week	239 (38.8)	1641 (52.1)	1031 (39.1)	7433 (51.9)

Missing	29 (4.7)	110 (3.5)	72 (2.7)	261 (1.8)

Smoking status

Nonsmoker	297 (48.2)	1691 (53.7)	1088 (41.2)	7184 (50.2)

Former smoker	275 (44.6)	1291 (41.0)	1348 (51.1)	6029 (42.1)

Smoker	44 (7.1)	168 (5.3)	203 (7.7)	1105 (7.7)

Sleep quality

Satisfied or very satisfied	373 (60.6)	2014 (63.9)	1615 (61.2)	9114 (63.7)

Neutral	116 (18.8)	513 (16.3)	388 (14.7)	2158 (15.1)

Dissatisfied or very dissatisfied	127 (20.6)	617 (19.6)	635 (24.1)	3038 (21.2)

Missing	–	6 (0.2)	1 (0.0)	8 (0.1)

Nutritional risk status

Low risk	394 (64.0)	2256 (71.6)	1577 (59.8)	10 128 (70.7)

High risk	201 (32.6)	796 (25.3)	1008 (38.2)	3919 (27.4)

Missing	21 (3.4)	98 (3.1)	54 (2.0)	271 (1.9)

Weight classification^§

Normal weight	112 (18.2)	1193 (37.9)	383 (14.5)	4827 (33.7)

Overweight	248 (40.3)	1312 (41.7)	967 (36.6)	6086 (42.5)

Obese	253 (41.1)	638 (20.3)	1277 (48.4)	3365 (23.5)

Missing	3 (0.5)	7 (0.2)	12 (0.5)	40 (0.3)

↵* The place of residence classification (urban or rural) was derived by CLSA based on Statistics Canada’s Postal Code Conversion File, which defines rural areas as those with a total population of fewer than 10 000 people.
↵† Other provinces are Alberta, Manitoba, Nova Scotia, Prince Edward Island, Newfoundland and Labrador, and Saskatchewan.
↵‡ Missing data on medical conditions: living with pain (n = 262, 1.3%), bowel disorders (n = 49, 0.2%), arthritis (n = 168, 0.8%), heart disease (n = 27, 0.1%), kidney disease (n = 41, 0.2%), stroke (n = 35, 0.2%), cancer (n = 19, 0.1%), hypertension (n = 2472, 11.9%), anxiety disorder (n = 25, 0.1%).
↵§ Based on body mass index international classification for adults aged ≥ 18 years.

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Table 2:

Three-year incidence and risk of depression, stratified by immigration and diabetes status

Variable	No. (%) of participants			Weighted OR (95% CI)^*

	Depression	No depression	Total	Crude	Adjusted
Immigrant

Diabetes	60 (9.7)	556 (90.3)	616	1.19 (0.86–1.65)

No diabetes	265 (8.4)	2885 (91.6)	3150

Nonimmigrant

Diabetes	279 (10.6)	2360 (89.4)	2639	1.35 (1.15–1.57)

No diabetes	1200 (8.4)	13 035 (91.6)	14 318

Diabetes v. no diabetes					1.18 (1.01–1.37)

Interaction effect of immigration status and diabetes at baseline

Immigrant with diabetes v. immigrant without diabetes					1.12 (0.80–1.56)

Immigrant with diabetes v. nonimmigrant with diabetes					1.01 (0.72–1.41)

Immigrant without diabetes v. nonimmigrant without diabetes					1.15 (0.98–1.35)

Nonimmigrant with diabetes v. nonimmigrant without diabetes					1.27 (1.08–1.49)

Note: CI = confidence interval, OR = odds ratio.
↵* The model included all the variables listed in Appendix 1, Table 1. Immigration status, sex and age were forced in all models. We removed other variables that were not significant (p > 0.5), which did not affect the Bayesian Information Criterion upon inclusion and which did not modify the effect of the main exposure variable by more than 10%. Survey weights were provided by the Canadian Longitudinal Study on Aging. The full model is available in Appendix 1, Table 2.

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Table 3:

Baseline characteristics of Cohort 2 individuals with and without depression by immigration status

Characteristic	Immigrant		Nonimmigrant

	No. (%) of participants with depression n = 762	No. (%) of participants without depression n = 3151	No. (%) of participants with depression n = 3797	No. (%) of participants without depression n = 14 344
Age, yr

45–60	325 (42.7)	1173 (37.2)	1941 (51.1)	7053 (49.2)

61–70	235 (30.8)	1048 (33.3)	1087 (28.6)	4228 (29.5)

71–85	202 (26.5)	930 (29.5)	769 (20.3)	3063 (21.4)

Sex

Male	266 (34.9)	1741 (55.3)	1351 (35.6)	7175 (50.0)

Female	496 (65.1)	1410 (44.7)	2446 (64.4)	7169 (50.0)

Marital status

Single	68 (8.9)	149 (4.7)	485 (12.8)	1178 (8.2)

Married	465 (61.0)	2403 (76.3)	2223 (58.5)	10417 (72.6)

Widowed, divorced or separated	227 (29.8)	598 (19.0)	1088 (28.7)	2745 (19.1)

Missing	2 (0.3)	1 (0.0)	1 (0.0)	4 (0.0)

Language most spoken at home

French	65 (8.5)	205 (6.5)	925 (24.4)	3174 (22.1)

English	597 (78.3)	2598 (82.5)	2861 (75.3)	11137 (77.6)

Other	58 (7.6)	254 (8.1)	7 (0.2)	17 (0.1)

Missing	42 (5.5)	94 (3.0)	4 (0.1)	16 (0.1)

Ethnic or racial background

White	629 (82.5)	2641 (83.8)	3758 (99.0)	14191 (98.9)

Black	24 (3.1)	89 (2.8)	8 (0.2)	19 (0.1)

South Asian	36 (4.7)	122 (3.9)	2 (0.1)	6 (0.0)

Chinese	17 (2.2)	107 (3.4)	7 (0.2)	37 (0.3)

Other	53 (7.0)	188 (6.0)	20 (0.5)	81 (0.6)

Missing	3 (0.4)	4 (0.1)	2 (0.1)	10 (0.1)

Years since arrival to Canada

< 20	112 (14.7)	395 (12.5)	–	–

20–40	190 (24.9)	783 (24.8)	–	–

> 40	460 (60.4)	1973 (62.6)	–	–

Total household income, $

< 20 000	57 (7.5)	82 (2.6)	332 (8.7)	436 (3.0)

20 000–50 000	208 (27.3)	591 (18.8)	923 (24.3)	2443 (17.0)

50 000–100 000	246 (32.3)	1075 (34.1)	1217 (32.1)	4794 (33.4)

> 100 000	194 (25.5)	1180 (37.4)	1088 (28.7)	5854 (40.8)

Missing	57 (7.5)	223 (7.1)	237 (6.2)	817 (5.7)

Working status

Employed	297 (39.0)	1332 (42.3)	1510 (39.8)	6373 (44.4)

Unemployed	71 (9.3)	111 (3.5)	313 (8.2)	468 (3.3)

Retired	393 (51.6)	1701 (54.0)	1964 (51.7)	7474 (52.1)

Missing	1 (0.1)	7 (0.2)	10 (0.3)	29 (0.2)

Education level

Less than secondary school	30 (3.9)	76 (2.4)	260 (6.8)	595 (4.1)

Secondary school	64 (8.4)	196 (6.2)	367 (9.7)	1278 (8.9)

Postsecondary degree or diploma	664 (87.1)	2871 (91.1)	3166 (83.4)	12454 (86.8)

Missing	4 (0.5)	8 (0.3)	4 (0.1)	17 (0.1)

Place of residence^*

Rural	75 (9.8)	310 (9.8)	453 (11.9)	1850 (12.9)

Urban	674 (88.5)	2800 (88.9)	3293 (86.7)	12328 (85.9)

Missing	13 (1.7)	41 (1.3)	51 (1.3)	166 (1.2)

Province

Quebec	111 (14.6)	365 (11.6)	922 (24.3)	3204 (22.3)

British Columbia	227 (29.8)	995 (31.6)	665 (17.5)	2735 (19.1)

Ontario	223 (29.3)	872 (27.7)	855 (22.5)	2921 (20.4)

Other^†	201 (26.4)	919 (29.2)	1355 (35.7)	5484 (38.2)

Medical conditions^‡

Living with pain	366 (48.0)	945 (30.0)	1904 (50.1)	4267 (29.7)

Bowel disorders	105 (13.8)	227 (7.2)	582 (15.3)	1136 (7.9)

Arthritis	28 (3.7)	83 (2.6)	160 (4.2)	354 (2.5)

Heart disease	280 (36.7)	1009 (32.0)	1442 (38.0)	4364 (30.4)

Kidney disease	17 (2.2)	67 (2.1)	109 (2.9)	294 (2.0)

Stroke	15 (2.0)	37 (1.2)	67 (1.8)	157 (1.1)

Cancer	117 (15.4)	474 (15.0)	573 (15.1)	2012 (14.0)

Hypertension	283 (37.1)	1080 (34.3)	1457 (38.4)	4870 (34.0)

Anxiety disorder	119 (15.6)	109 (3.5)	919 (24.2)	611 (4.3)

Alcohol consumption

Never	101 (13.3)	310 (9.8)	528 (13.9)	1218 (8.5)

About once a month	171 (22.4)	512 (16.2)	756 (19.9)	2259 (15.7)

2–4 times a month	150 (19.7)	574 (18.2)	827 (21.8)	3166 (22.1)

> 2 times a week	310 (40.7)	1645 (52.2)	1625 (42.8)	7436 (51.8)

Missing	30 (3.9)	110 (3.5)	61 (1.6)	265 (1.8)

Smoking status

Nonsmoker	377 (49.5)	1690 (53.6)	1644 (43.3)	7200 (50.2)

Former smoker	315 (41.3)	1293 (41.0)	1690 (44.5)	6040 (42.1)

Smoker	70 (9.2)	168 (5.3)	463 (12.2)	1104 (7.7)

Sleep quality

Satisfied or very satisfied	339 (44.5)	2014 (63.9)	1692 (44.6)	9133 (63.7)

Neutral	132 (17.3)	513 (16.3)	588 (15.5)	2162 (15.1)

Dissatisfied or very dissatisfied	291 (38.2)	618 (19.6)	1512 (39.8)	3041 (21.2)

Missing	–	6 (0.2)	5 (0.1)	8 (0.1)

Nutritional risk status

Low risk	381 (50.0)	2256 (71.6)	1772 (46.7)	10147 (70.7)

High risk	356 (46.7)	797 (25.3)	1941 (51.1)	3924 (27.4)

Missing	25 (3.3)	98 (3.1)	84 (2.2)	273 (1.9)

Weight classification^§

Normal weight	264 (34.6)	1194 (37.9)	1205 (31.7)	4838 (33.7)

Overweight	310 (40.7)	1313 (41.7)	1423 (37.5)	6094 (42.5)

Obese	184 (24.1)	637 (20.2)	1144 (30.1)	3372 (23.5)

Missing	4 (0.5)	7 (0.2)	25 (0.7)	40 (0.3)

↵* The place of residence classification (urban or rural) was derived by CLSA based on Statistics Canada’s Postal Code Conversion File, which defines rural areas as those with a total population of fewer than 10 000 people.
↵† Other provinces are Alberta, Manitoba, Nova Scotia, Prince Edward Island, Newfoundland and Labrador, and Saskatchewan.
↵‡ Missing data on medical conditions: living with pain (n = 293, 1.3%), bowel disorders (n = 51, 0.2%), arthritis (n = 197, 0.9%), heart disease (n = 33, 0.1%), kidney disease (n = 44, 0.2%), stroke (n = 37, 0.2%), cancer (n = 25, 0.1%), hypertension (n = 2438, 11.0%), anxiety disorder (n = 44, 0.2%).
↵§ Based on body mass index international classification for adults aged ≥ 18 years.

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Table 4:

Three-year incidence and risk of diabetes, stratified by immigration and depression status

Variable	No. (%) of participants			Weighted OR (95% CI)^*

	Diabetes	No diabetes	Total	Crude	Adjusted
Immigrant

Depression	54 (7.1)	708 (92.9)	762	1.66 (1.16–2.39)

No depression	144 (4.6)	2970 (95.4)	3151

Nonimmigrant

Depression	257 (6.8)	3540 (93.2)	3797	1.55 (1.31–1.82)

No depression	693 (4.8)	13 651 (95.2)	14 344

Depression v. no depression					1.43 (1.21–1.68)

Interaction effect of immigrant status and depression at baseline

Immigrant with depression v. immigrant without depression					1.60 (1.08–2.37)

Immigrant with depression v. nonimmigrant without depression					1.10 (0.76–1.58)

Immigrant without depression v. nonimmigrant without depression					0.96 (0.76–1.21)

Nonimmigrant with depression v. nonimmigrant without depression					1.39 (1.16–1.68)

Note: CI = confidence interval, OR = odds ratio.
↵* The model included all the variables listed in Appendix 1, Table 3. Immigration status, sex and age were forced in all models. We removed other variables that were not significant (p > 0.5), which did not affect the Bayesian Information Criterion upon inclusion and which did not modify the effect of the main exposure variable by more than 10%. Survey weights were provided by the Canadian Longitudinal Study on Aging. The full model is available in Appendix 1, Table 2.