Results of mediation analysis for the total sample, women (n=3890) and men (n=3321): total, direct and indirect effects of area-level socioeconomic status on mental health (outcomes): the Tromsø Study 2015–2016
| Effects | Anxiety symptoms | Depression symptoms | Insomnia symptoms | |||
| Women | Men | Women | Men | Women | Men | |
| B (95% CI) | B (95% CI) | B (95% CI) | B (95% CI) | B (95% CI) | B (95% CI) | |
| Total effect* | −0.09 (−0.23 to 0.04) | 0.05 (−0.07 to 0.18) | −0.25 (−0.36 to 0.13) | −0.15 (−0.29 to 0.02) | −0.81 (−1.28 to 0.33) | −0.09 (−0.56 to 0.36) |
| No significant interaction with age | No significant interaction with age | No significant interaction with age | No significant interaction with age | No significant interaction with age | No significant interaction with age | |
| Direct effect† | −0.07 (−0.22 to 0.05) | 0.07 (−0.07 to 0.19) | −0.16 (−0.29 to 0.04) | −0.10 (−0.24 to 0.04) | −0.65 (−1.21 to 0.24) | 0.01 (−0.46 to 0.47) |
| No significant interaction with age | No significant interaction with age | No significant interaction with age | No significant interaction with age | No significant interaction with age | No significant interaction with age | |
| Indirect effect, combined‡ | −0.02 (−0.05 to 0.03) | −0.01 (−0.04 to 0.03) | −0.09 (−0.13 to 0.03) | −0.05 (−0.09 to 0.02) | −0.16 (−0.25 to 0.08) | −0.10 (−0.23 to 0.01) |
| PME§ | 0.26 (−1.92 to 2.67) | −0.26 (−3.47 to 3.39) | 0.36 (0.16 to 0.75) | 0.35 (0.06 to 1.76) | 0.20 (−0.01 to 0.57) | 1.07 (−5.93 to 6.35) |
| Exposure-adjusted effects of mediators: | ||||||
| Smoking (ref: never) | Mediation | Mediation | Mediation | Mediation | No mediation | Mediation |
| Previous | 0.20 (−0.003 to 0.40) | 0.11 (−0.08 to 0.30) | 0.03 (−0.15 to 0.21) | 0.05 (−0.15 to 0.26) | 0.21 (−0.49 to 0.91) | 0.73 (0.06 to 1.40) |
| Occasional | 0.38 (−0.18 to 0.94) | 0.73 (0.29 to 1.17) | 0.35 (−0.14 to 0.84) | 0.16 (−0.32 to 0.64) | −0.17 (−2.09 to 1.75) | 1.41 (−0.16 to 2.99) |
| Current | 0.56 (0.25 to 0.87) | 0.30 (0.005 to 0.59) | 0.81 (0.54 to 1.08) | 0.33 (0.01 to 0.65) | 0.23 (−0.84 to 1.32) | 0.06 (−0.98 to 1.10) |
| Alcohol (ref: 0 units) | No mediation | No mediation | Mediation | Mediation | No mediation | No mediation |
| 1–2 units | 0.09 (−0.27 to 0.44) | 0.05 (−0.40 to 0.50) | −0.61 (−0.93 to 0.30) | −0.45 (−0.93 to 0.03) | −0.88 (−2.11 to 0.35) | 0.51 (−1.03 to 2.05) |
| 3–4 units | 0.14 (−0.26 to 0.55) | 0.09 (−0.37 to 0.56) | −0.58 (−0.95 to 0.23) | −0.53 (−1.03 to 0.03) | −0.06 (−1.47 to 1.36) | 0.63 (−0.97 to 2.22) |
| 5 or more | 0.62 (−0.11 to 1.36) | 0.20 (−0.31 to 0.72) | 0.02 (−0.62 to 0.67) | −0.28 (−0.84 to 0.28) | 1.77 (−0.77 to 4.31) | 1.70 (−0.09 to 3.49) |
| Snuff (ref: never) | No mediation | No mediation | No mediation | No mediation | No mediation | No mediation |
| Previous | 0.34 (−0.36 to 1.04) | 0.26 (−0.05 to 0.58) | 0.46 (−0.14 to 1.06) | 0.32 (−0.03 to 0.66) | −0.11 (−2.45 to 2.45) | 1.06 (−0.07 to 2.18) |
| Current | 0.67 (−0.0004 to 1.34) | 0.27 (−0.05 to 0.60) | 0.62 (0.04 to 1.22) | −0.04 (−0.40 to 0.31) | 3.22 (0.92 to 5.53) | 1.17 (0.01 to 2.33) |
| Physical activity (ref: Sedentary) | No mediation | No mediation | Mediation | Mediation | Mediation | Mediation |
| Light activity | −0.07 (−0.37 to 0.22) | −0.13 (−0.39 to 0.12) | −0.96 (−1.21 to 0.70) | −0.81 (−1.08 to 0.54) | −1.53 (−2.55 to 0.52) | −2.02 (−2.92 to 1.12) |
| Moderate-to-vigorous activity | −0.12 (−0.47 to 0.22) | −0.26 (−0.53 to 0.01) | −1.14 (−1.44 to 0.84) | −1.16 (−1.46 to 0.87) | −1.85 (−3.05 to 0.68) | −2.49 (−3.45 to 1.52) |
All models were adjusted for age and individual-level SES and accounted for area-level clustering.
Bold typeface indicates significance.
*Association between exposure and outcome: main effect presented when age is not a significant moderator; age-specific associations presented when age was a significant moderator.
†Association between exposure and outcome not explained by mediators.
‡Association between exposure and outcome through mediators (dietary variables not included).
§The proportion of the total effect mediated by mediator(s).
B, regression coefficient; CI, confidence interval; PME, proportion of mediated effect; SES, socioeconomic status.