Table 1 Baseline characteristics according to baseline levels of serum interleukin-1 beta (sIL-1β) and the Neuroticism of the Big Five Inventory in patients with depressive disorders (N = 1086).
Lower Neuroticism | Higher Neuroticism | Statistical coefficients for group differencesa | Post-hoc comparisons (P < 0.05) | |||
|---|---|---|---|---|---|---|
Lower sIL-1β (N = 334): 1 | Higher sIL-1β (N = 285): 2 | Lower sIL-1β (N = 205): 3 | Higher sIL-1β (N = 262): 4 | |||
Socio-demographic characteristics | ||||||
Age, mean (SD) years | 61.8 (12.2) | 55.2 (16.1) | 57.0 (13.1) | 52.6 (16.1) | F = 22.053 P < 0.001 | 1 > 2,3 > 4 |
Sex, N (%) female | 241 (72.2) | 192 (67.4) | 138 (67.3) | 174 (66.4) | χ2 = 2.900 P = 0.407 | n-s |
Education, mean (SD) years | 8.2 (4.8) | 9.4 (4.9) | 8.9 (4.7) | 10.1 (4.5) | F = 8.541 P < 0.001 | 1 < 2,4 |
Marital status, N (%) unmarried | 93 (27.8) | 91 (31.9) | 48 (23.4) | 94 (35.9) | χ2 = 9.785 P = 0.020 | 3 < 4 |
Living alone, N (%) | 59 (17.7) | 46 (16.1) | 20 (9.8) | 42 (16.0) | χ2 = 6.534 P = 0.088 | n-s |
Unemployed status, N (%) | 91 (27.2) | 80 (28.1) | 62 (30.2) | 83 (31.7) | χ2 = 1.678 P = 0.642 | n-s |
Monthly income, N (%) < 2,000 USD | 210 (62.9) | 172 (60.4) | 122 (59.5) | 144 (55.0) | χ2 = 3.895 P = 0.273 | n-s |
Clinical characteristics | ||||||
Major depressive disorder, N (%) | 294 (88.0) | 232 (81.4) | 181 (88.3) | 218 (83.2) | χ2 = 7.740 P = 0.052 | n-s |
Melancholic feature, N (%) | 52 (15.6) | 46 (16.1) | 29 (14.1) | 35 (13.4) | χ2 = 1.045 P = 0.790 | n-s |
Atypical feature, N (%) | 14 (4.2) | 22 (7.7) | 9 (4.4) | 24 (9.2) | χ2 = 8.314 P = 0.040 | 1,3 < 4 |
Age at onset, mean (SD) years | 55.8 (14.8) | 49.2 (17.4) | 51.0 (14.6) | 46.6 (17.4) | F = 17.552 P < 0.001 | 1 > 2,3 > 4 |
Duration of illness, mean (SD) years | 6.3 (9.5) | 6.3 (9.9) | 6.3 (8.8) | 6.2 (8.8) | F = 0.004 P = 1.000 | n-s |
Number of depressive episodes, mean (SD) | 1.7 (1.3) | 1.6 (1.3) | 1.7 (1.3) | 1.5 (1.3) | F = 7.011 P < 0.001 | 1,2,3 < 4 |
Duration of present episode, mean (SD) months | 6.9 (9.9) | 7.0 (10.4) | 7.6 (10.3) | 8.3 (11.2) | F = 0.967 P = 0.408 | n-s |
Family history of depression, N (%) | 50 (15.0) | 37 (13.0) | 24 (11.7) | 47 (17.9) | χ2 = 4.364 P = 0.225 | n-s |
Number of physical disorders, mean (SD) | 1.6 (1.2) | 1.5 (1.2) | 1.9 (1.3) | 1.6 (1.3) | F = 2.584 P = 0.052 | n-s |
Body mass index, mean (SD) kg/m2 | 23.4 (2.8) | 23.2 (3.4) | 23.1 (3.0) | 23.1 (3.5) | F = 0.450 P = 0.717 | n-s |
Current smoking, N (%) | 29 (8.7) | 36 (12.6) | 23 (11.2) | 35 (13.4) | χ2 = 3.888 P = 0.274 | n-s |
Assessment scales, mean (SD) scores | ||||||
Hospital anxiety & depression scale-depression subscale | 13.2 (4.0) | 13.2 (4.1) | 14.4 (3.8) | 14.3 (3.7) | F = 8.384 P < 0.001 | 1,2 < 3,4 |
Hospital anxiety & depression scale-anxiety subscale | 11.0 (4.0) | 11.7 (4.2) | 12.4 (3.9) | 12.5 (3.8) | F = 9.165 P < 0.001 | 1 < 3,4 |
Social and Occupational functioning assessment scale | 56.4 (7.4) | 56.3 (7.7) | 56.0 (6.8) | 54.9 (7.7) | F = 2.250 P = 0.081 | n-s |
Alcohol use disorder identification test | 4.2 (7.2) | 5.6 (9.1) | 4.9 (8.5) | 7.0 (10.5) | F = 5.366 P = 0.001 | 1 < 4 |
