Design and logistics | |
Sample size (n), median (range)* | 3370 (367–11 552) |
Proportion of baseline participants who provided | 83% (37–100%) |
follow-up data, median (range) | |
Follow-up period (years), median (range) | 2.5 (1–13) |
Data collection and quality assurance | |
Diagnosis by diagnostic manual or specialist in | 7 Studies19 20 |
psychology or psychiatry | 22 23 25 27 29 |
Self-administered questionnaire | 7 Studies14–16 18 23 26 28 |
Ascertainment of outcome | |
Telephone interview | 4 Studies21 22 24 27 |
Face-to-face interview | 4 Studies17 19 20 29 |
Clinical case | 1 Study25 |
Multi-item measures of psychosocial factors | All except for 4 studies17 23 27 28 |
Partly or entirely independent assessment of | 2 Studies23 25 |
exposure | |
Complete reporting of risk estimates | 9 Studies14 16 18 |
regardless of statistical significance | 20 21 23 25 26 29 |
Data analysis | |
Exclusion of baseline cases | All except for 4 studies17–19 24 |
Analyses of first- and later-onset depressive | 9 Studies15 16 18 20–22 |
episodes | 24 25 27 |
Adjustment for | |
Demographic covariates (age, gender, | All except for 1 |
education, socio-economic class, | study15 |
employment status, marital status) | |
Life events and domestic stressors | 6 Studies14 16 18 23 27 29 |
Family history of depression | 3 Studies23 24 27 |
Earlier depressive episodes | 2 Studies18 23 |
Chronic disease or disability | 1 Study20 |
Personality traits | 3 Studies14 17 23 |
Analyses of | |
Exposure–response relationships | 5 Studies21 22 24 26 29 |
(intensity and duration of exposure) | |
Exposure–effect relationships | 2 Studies27 29 |
Exposure-time outcome-onset specificity | 1 Study25 |
*A nation-wide study with >100 000 persons not included in descriptive statistics.25