Table 2. Individual factors associated with development of severe psychological distress: mixed-effect ordinal logistic regression results.
| ORa | 95% CI | P | |
| Gender | |||
| Male | 1.00 | ||
| Female | 0.87 | (0.63–1.20) | 0.389 |
| Age | |||
| 20–29 years | 1.26 | (0.73–2.16) | 0.403 |
| 30–39 years | 1.22 | (0.73–2.05) | 0.449 |
| 40–49 years | 1.39 | (0.84–2.32) | 0.202 |
| 50–59 years | 1.00 | ||
| 60–69 years | 1.04 | (0.59–1.83) | 0.899 |
| 70–79 years | 0.79 | (0.40–1.56) | 0.497 |
| Residential area | |||
| Northern Kanto (Ibaraki, Tochigi, or Gumma Prefectures) | 1.01 | (0.62–1.65) | 0.963 |
| Saitama Prefecture | 1.22 | (0.82–1.82) | 0.321 |
| Chiba Prefecture | 1.02 | (0.65–1.59) | 0.942 |
| Tokyo Metropolitan | 1.00 | ||
| Kanagawa Prefecture | 1.13 | (0.79–1.63) | 0.507 |
| Working status | |||
| No | 1.11 | (0.77–1.59) | 0.590 |
| Yes | 1.00 | ||
| Marital status | |||
| Never married, divorced, or separated | 1.06 | (0.71–1.60) | 0.767 |
| Married | 1.00 | ||
| Living arrangement | |||
| Living alone | 1.08 | (0.74–1.60) | 0.682 |
| Living with others but without children | 1.00 | ||
| Living with children aged ≥18 years | 0.94 | (0.55–1.59) | 0.811 |
| Living with children aged <18 years | 0.85 | (0.52–1.36) | 0.491 |
| Education (years) | |||
| Junior or high school (≤12 years) | 0.98 | (0.69–1.39) | 0.914 |
| College (13–15 years) | 0.99 | (0.68–1.45) | 0.967 |
| University or higher (≥16 years) | 1.00 | ||
| Others | 0.29 | (0.07–1.26) | 0.098 |
| Smoking status | |||
| Current | 1.00 | ||
| Quit | 1.17 | (0.78–1.74) | 0.446 |
| Never | 1.21 | (0.78–1.87) | 0.388 |
| Drinking alcohol | |||
| No | 1.00 | ||
| Seldom (1–4 days/week) | 1.11 | (0.81–1.52) | 0.517 |
| Often (5–7 days/week) | 1.16 | (0.78–1.74) | 0.458 |
| Walking time, min/day | |||
| <30 | 1.47 | (0.96–2.24) | 0.075 |
| 30–59 | 1.27 | (0.80–2.00) | 0.306 |
| ≥60 | 1.00 | ||
| Vaccinated regularly | |||
| Yes | 1.00 | ||
| No | 1.09 | (0.68–1.73) | 0.724 |
| Annual personal income, United States dollars | |||
| <18,600 | 2.12 | (1.16–3.86) | 0.014 |
| 18,600–<37,200 | 1.95 | (1.10–3.46) | 0.022 |
| 37,200–<55,800 | 1.19 | (0.65–2.17) | 0.572 |
| ≥55,800 | 1.00 | ||
| Comorbidities | |||
| Hypertension | 0.82 | (0.53–1.27) | 0.374 |
| Diabetes | 1.27 | (0.67–2.43) | 0.460 |
| Heart disease | 1.71 | (0.74–3.97) | 0.210 |
| Stroke | 1.30 | (0.26–6.50) | 0.746 |
| Respiratory disease | 2.56 | (1.51–4.34) | <0.001 |
| Kidney disease | 0.64 | (0.08–5.03) | 0.668 |
| Cancer | 0.34 | (0.09–1.31) | 0.117 |
| Baseline K6 score | 1.43 | (1.39–1.48) | <0.001 |
K6, Kessler’s Six-scale Psychological Distress Scale; OR, odds ratio.
Bold values denote statistical significance at the P < 0.05 level.
aOdds ratios were calculated with adjustment for all other variables (ie, gender, age, residential area, working status, marital status, living arrangement, education, smoking status, drinking alcohol, walking time, regular vaccination, annual personal income, comorbidities and K6 score at baseline).