Table 1.
Characteristics of the study variables among all current daily cigarette smokers with sufficient information on their depression status (n=1,432) by CES-D categorization in the Finnish Twin Cohort in 2011.
| Confounder / independent variable |
Depression status | ||
|---|---|---|---|
| Non-depressed CES-D <20 N=1,145 |
Depressed CES-D ≥20 N=287 |
Inferential statistic a |
|
| n (%) | n (%) | p-value | |
| Sex | |||
| Man | 596 (52.1) | 112 (39.0) | 7.90e-05 |
| Woman | 549 (47.9) | 175 (61.0) | |
| Missing | 0 | 0 | |
| Marital status | |||
| Married or living together | 714 (62.4) | 137 (47.7) | 7.43e-05 |
| Single | 160 (14.0) | 54 (18.8) | |
| Divorced or widowed | 263 (23.0) | 95 (33.1) | |
| Missing | 8 (0.7) | 1 (0.4) | |
| Working status | |||
| At work | 618 (54.0) | 79 (27.5) | 1.10e-14 |
| Not at work | 524 (45.8) | 207 (72.1) | |
| Missing | 3 (0.3) | 1 (0.4) | |
| Self-rated health | |||
| Excellent/very good | 688 (60.1) | 75 (26.1) | 7.76e-33 |
| Good | 384 (33.5) | 140 (49.8) | |
| Fair/poor | 63 (5.5) | 70 (24.4) | |
| Missing | 10 (0.9) | 2 (0.7) | |
| Leisure time physical activity a | |||
| Active (>1.5 MET-h/day) | 581 (50.7) | 118 (41.1) | 7.03e-03 |
| Inactive (≤1.5 MET-h/day) | 542 (47.3) | 159 (55.4) | |
| Missing | 22 (1.9) | 10 (3.5) | |
| Number of pass outs due to alcohol in the last year | |||
| Never | 960 (83.8) | 210 (73.2) | 1.07e-06 |
| 1-3 times | 133 (11.6) | 52 (18.1) | |
| At least 4 times | 25 (2.2) | 21 (7.3) | |
| Missing | 27 (2.4) | 4 (1.4) | |
| Sleep length | |||
| 7 – <9 hours | 772 (67.4) | 148 (51.6) | 9.63e-06 |
| <7 hours | 290 (25.3) | 110 (38.3) | |
| ≥9 hours | 78 (6.8) | 26 (9.1) | |
| Missing | 5 (0.4) | 3 (1.1) | |
| Sleep quality | |||
| Well | 323 (28.2) | 31 (10.8) | 6.88e-24 |
| Rather well | 639 (55.8) | 134 (46.7) | |
| Rather poorly | 138 (12.1) | 81 (28.2) | |
| Poorly | 33 (2.9) | 35 (12.2) | |
| Missing | 12 (1.1) | 6 (2.1) | |
| Life satisfaction | |||
| Satisfied | 274 (23.9) | 7 (2.4) | 3.5e-109 |
| Intermediate | 773 (67.5) | 85 (29.6) | |
| Dissatisfied | 98 (8.6) | 194 (67.6) | |
| Missing | 0 (0) | 1 (0.4) | |
| Emotional support | |||
| Strong support | 1,041 (90.9) | 207 (72.1) | 6.37e-17 |
| Some support | 61 (5.3) | 42 (14.6) | |
| Not any support | 37 (3.2) | 37 (12.9) | |
| Missing | 6 (0.5) | 1 (0.4) | |
| Negative life events (weighted sum score) | |||
| Quartile 1 (lowest) | 368 (32.1) | 31 (10.8) | 1.98e-20 |
| Quartile 2 | 186 (16.2) | 31 (10.8) | |
| Quartile 3 | 251 (21.9) | 56 (19.5) | |
| Quartile 4 (Highest) | 306 (26.7) | 148 (51.6) | |
| Missing | 34 (3.0) | 21 (7.3) | |
| Involved in a serious traffic accident in adulthood * | |||
| No | 866 (75.6) | 195 (67.9) | 2.91e-02 |
| Yes | 86 (7.5) | 28 (9.8) | |
| Missing | 193 (16.9) | 64 (22.3) | |
| Injured by physical assault in adulthood * | |||
| No | 823 (71.9) | 152 (53.0) | 1.46e-10 |
| Yes | 144 (12.6) | 77 (26.8) | |
| Missing | 178 (15.6) | 58 (20.2) | |
| Victim of sexual assault in childhood * | |||
| No | 1,028 (89.8) | 216 (75.3) | 2.12e-12 |
| Yes | 19 (1.7) | 24 (8.4) | |
| Missing | 98 (8.6) | 47 (16.4) | |
| Victim of sexual assault in adulthood * | |||
| No | 906 (79.1) | 176 (61.3) | 8.08e-15 |
| Yes | 55 (4.8) | 51 (17.8) | |
| Missing | 184 (16.1) | 60 (20.9) | |
| Victim of or witness to a violent crime in adulthood * | |||
| No | 927 (81.0) | 207 (72.1) | 9.18e-04 |
| Yes | 39 (3.4) | 21 (7.3) | |
| Missing | 179 (15.6) | 59 (20.6) | |
| Parental divorce or separation in childhood * | |||
| No | 958 (83.7) | 221 (77.0) | 3.00e-02 |
| Yes | 86 (7.5) | 30 (10.5) | |
| Missing | 101 (8.8) | 36 (12.5) | |
| Dichotomy of traumatic life events (*) c | |||
| None | 615 (53.7) | 90 (31.4) | 5.46e-10 |
| At least one | 237 (20.7) | 89 (31.0) | |
| Missing info in 1- 5 traumas | 277 (24.2) | 101 (35.2) | |
| Missing info in all 6 traumas | 16 (1.4) | 7 (2.4) | |
| Mean (SD) | Mean (SD) | ||
| Age (years, range 53.3 – 67.3) | 59.5 (3.5) | 59.2 (3.6) | 2.05e-01 |
| Missing, n (%) | 0 (0) | 0 (0) | |
| Education by 1981 (years, range 3 - 16) b | 8.0 (2.5) | 7.6 (2.3) | 2.41e-02 |
| Missing, n (%) | 2 (0) | 1 (0) | |
| Alcohol consumption (drinks [12 g alcohol]/day, range 0 - 22.6) | 1.4 (2.1) | 1.7 (2.9) | 6.85e-01 |
| Missing, n (%) | 2 (0) | 1 (0) | |
| Number of cigarettes (per day, range 0 - 40) | 14.0 (7.4) | 15.5 (8.4) | 3.35e-01 |
| Missing, n (%) | 4 (0) | 2 (1) | |
| Neuroticism (sum score, range 0 - 10) | 3.0 (2.2) | 6.6 (2.1) | 5.0e-108 |
| Missing, n (%) | 30 (3) | 7 (2) | |
| FTCD (sum score, range 0 - 10) | 3.8 (2.3) | 4.6 (2.4) | 4.67e-08 |
| Missing, n (%) | 13 (1) | 1 (0) | |
| WISDM PDM Motives (sum, range 16 - 112) | 55.3 (23.6) | 67.4 (26.8) | 3.00e-13 |
| Missing, n (%) | 39 (3) | 13 (5) | |
| WISDM AE Motives (sum, range 3 - 21) | 10.9 (4.8) | 13.3 (5.1) | 6.43e-14 |
| Missing, n (%) | 14 (1) | 6 (2) | |
| WISDM Taste Motives (sum, range 3 - 21) | 11.6 (4.7) | 12.2 (5.3) | 9.35e-02 |
| Missing, n (%) | 13 (1) | 6 (2) | |
The Center for Epidemiological Studies-Depression (CES-D), The Wisconsin Inventory of Smoking Dependence Motives (WISDM), WISDM Primary Dependence Motives (PDM), WISDM Affective Enhancement Motives (AE), WISDM Taste Motives (T), Fagerström Test for Cigarette Dependence (FTCD), Metabolic Equivalent (MET).
Pearson Chi-square test for categorical variables and two-sample t-test for continuous variables.
The latest information in data from 1981; corresponding information from the 1975 survey was used for those with missing information on their education in 1981.
A dichotomous variable (none vs at least one) of traumatic life events includes those traumatic life events that were related to depression and smoking dependence/motives (*).