Table 1.
Demographic and clinical characteristics of N=117 healthy controls and individuals with MDD at baseline.
| Baseline Healthy Controls (n=67†) |
Baseline MDD (n=50†) |
P^ | |||
|---|---|---|---|---|---|
| Baseline Demographic Characteristics | |||||
| Age in years, mean (SD) | 44.1 | (14.0) | 42.7 | (13.2) | |
| Sex, n (%) female | 39 | (58%) | 26 | (52%) | |
| Race, n (%) white | 49 | (73%) | 41 | (82%) | |
| Ethnicity, n (%) Hispanic/Latino | 2 | (3%) | 2 | (4%) | |
| Highest educational level, n (%) | |||||
| Graduate school | 22 | (33%) | 9 | (18%) | |
| College graduate | 28 | (42%) | 20 | (40%) | |
| Partial college | 13 | (19%) | 14 | (28%) | |
| High school graduate or lower | 4 | (6%) | 7 | (14%) | |
| Marital status, n (%) living with partner/married | 31 | (46%) | 9 | (18%) | ** |
| Baseline Clinical Characteristics | |||||
| MADRS total score, mean (SD) | 2.4 | (2.9) | 30.0 | (5.6) | *** |
| HAM-A total score, mean (SD) | 3.2 | (2.3) | 18.0 | (4.7) | *** |
| PSS total score, mean (SD) over past month | 8.2 | (5.9) | 25.6 | (5.9) | *** |
| ETISR-SF total score, mean (SD) | 2.7 | (2.8) | 7.6 | (5.3) | *** |
| TEQ total score, mean (SD) | 1.1 | (1.4) | 2.3 | (2.2) | ** |
| MDD duration total months, mean (SD) | n/a | 128.9 | (122.5) | ||
| Antidepressant use >6 months, n (%) | n/a | 25 | (52%) | ||
| Lifetime alcohol or substance use disorder, n (%) | 7 | (10%) | 11 | (22%) | |
| Cigarette smoking pack-years, mean (SD) | 8.0 | (17.3) | 6.8 | (12.5) | |
| BMI, mean (SD) | 24.3 | (3.8) | 26.0 | (4.7) | * |
| Past year exercise level, n (%) more than once a week | 61 | (91%) | 30 | (63%) | *** |
| Δ Clinical Characteristics from Baseline to Follow-up | |||||
| TEQ (total score, based on past two years), mean (SD) | 0.2 | (0.5) | 0.8 | (1.2) | ** |
| MDD duration total months (BL to FU), mean (SD) | 0.4 | (2.6) | 11.8 | (7.6) | *** |
| Antidepressant use >6 months (BL to FU), n (%) | 0 | (0) | 15 | (37%) | *** |
| Onset of first alcohol or substance use disorder, n (%) | 0 | (0) | 7 | (15%) | ** |
| Cigarette smoking pack-years (BL to FU), mean (SD) | <0.1 | (<0.1) | 0.2 | (0.5) | * |
| Clinical Characteristics at Follow-up | |||||
| Current MDD diagnosis, n (%) | 1 | (2%) | 14 | (30%) | *** |
| MADRS total score, mean (SD) | 2.9 | (6.1) | 16.2 | (12.0) | *** |
| HAM-A total score, mean (SD) | 4.1 | (4.9) | 15.0 | (8.8) | *** |
| PSS total score, mean (SD) | 9.0 | (7.0) | 21.3 | (6.0) | *** |
| BMI, mean (SD) | 24.0 | (3.8) | 26.5 | (5.0) | ** |
| Exercised more than once a week, past year, n (%) | 44 | (86%) | 34 | (77%) | |
| Biological Outcome | |||||
| Baseline zRTL, mean (SD) | −0.010 | (0.953) | 0.013 | (1.070) | |
| Follow-up zRTL, mean (SD) | 0.223 | (0.956) | −0.299 | (0.988) | ** |
| Δ zRTL (BL to FU), mean (SD) | 0.233 | (1.323) | −0.313 | (1.240) | * |
Key: MDD = major depressive disorder, MADRS = Montgomery-Åsberg Depression Rating Scale (range: 0–60, where higher scores indicate greater depression severity), HAM-A = Hamilton Anxiety Rating Scale (range: 0–56, where higher scores indicate greater severity of anxiety), PSS = Perceived Stress Scale (range: 0–40, where higher scores indicate higher perceived stress), ETISR-SF = Early Trauma Inventory Self Report-Short Form, TEQ = Traumatic Events Questionnaire, BMI = body mass index, zRTL = z-score of relative telomere length;
= across measures, due to small amounts of missing data, sample sizes varied from n of 41 to 50 for the baseline MDD sample and from n of 51 to 67 for the control sample;
= significance of t-test for continuous variables and Fisher's Exact Test for categorical variables,
where = p < 0.05,
= p < 0.01,
= p <0 .001.