Table 1.
Clinical and demographic parameters of the study sample, with global methylation change in participants stratified according to early weight gain status
| N | Total sample | Controlsa (n = 40) | Casesa (n = 39) | p-valueb | |
|---|---|---|---|---|---|
| Age, median (range), y | 79 | 37 (16–84) | 37 (17–84) | 39 (16–83) | 0.56 |
| Men, n (%) | 79 | 40 (50.6) | 20 (50.0) | 20 (51.3) | 0.9 |
| Smoking, n (%) | 79 | 40 (50.6) | 26 (65.0) | 14 (35.9) | 0.01 |
| Main diagnosis, n (%) | 79 | 0.33 | |||
| Psychotic disorders (F20-F24; F28-F29) | 36 (45.6) | 17 (42.5) | 19 (48.7) | ||
| Schizoaffective disorders (F25) | 10 (12.7) | 6 (15.0) | 4 (10.3) | ||
| Bipolar disorders (F30–F31) | 18 (22.8) | 12 (30.0) | 6 (15.4) | ||
| Depressive disorders (F32–F33) | 8 (10.1) | 2 (5.0) | 6 (15.4) | ||
| Other | 7 (8.9) | 3 (7.5) | 4 (10.3) | ||
| Psychotropic treatment group, n (%)c | 79 | 0.74 | |||
| Low risk of WG | 13 (16.5) | 6 (15.0) | 7 (18.0) | ||
| Medium risk of WG | 42 (53.2) | 23 (57.5) | 19 (48.7) | ||
| High risk of WG | 24 (30.4) | 11 (27.5) | 13 (33.3) | ||
| BMI, median (range), kg/m2 | 79 | ||||
| Baseline | 23.1 (15.2–37.5) | 23.5 (17.1–36.5) | 21.9 (15.2–37.5) | 0.16 | |
| First month | 23.9 (17.0–39.5) | 23.8 (17.1–36.5) | 24.1 (17.0–39.5) | 0.81 | |
| p-valued | < 10–4 | < 10–4 | < 10–4 | ||
| WG, median (range), % | 2.4 (0–23.0) | 0.5 (0–2.4) | 7 (5.2–23.0) | < 10–4 | |
| Metabolic syndrome prevalence, n (%)e | 51 | ||||
| Baseline | 3 (5.9) | 3 (11.1) | 0 (0.0) | 0.09 | |
| First month | 8 (15.7) | 4 (14.8) | 4 (16.7) | 0.86 | |
| p-valued | 0.23 | 0.32 | 0.05 | ||
| Global baseline (T0) methylation (β-value), mean (range), % | 79 | 61.78 (58.52–64.01) | 61.80 (58.52–64.01) | 61.77 (59.20–63.86) | 0.87 |
| Global methylation (β-value) increase (T1–T0), mean (95%CI), % | 79 | 0.187 (0.185–0.190) | 0.201 (0.198–0.204) | 0.174 (0.170–0.177) | < 2.2 × 10–16 |
BMI body mass index, WG weight gain
aPatients who gained 5% or more of their initial weight were considered cases, and patients whose weight remained stable were considered controls
bStatistical significance for differences between groups was tested using the Wilcoxon Mann–Whitney rank-sum test for continuous variables (except for the differences in methylation levels which were assessed using Student’s t-test) and Pearson χ2 test of independence for categorical variables. Significant p-values (< 0.05) are indicated in bold
cPsychotropic drugs are considered to confer a low, medium and high risk of metabolic side effects for amisulpride and aripiprazole; risperidone, quetiapine, mirtazapine and lithium; and valproate, clozapine and olanzapine, respectively
dStatistical significance for differences between baseline and 1-month values was tested using the Wilcoxon signed rank test for matched pairs for continuous variables and McNemar test for categorical variables. Significant p values (< 0.05) are indicated in bold
eMetabolic syndrome was evaluated according to the definition of the International Diabetes Federation [28]