Table 3. Regression models with or without interaction terms.
| Model without interaction terms | Model with interaction terms | ||||||
|---|---|---|---|---|---|---|---|
| Variable (reference) | Category | B | SE | B | SE | ||
| Sex (female) | Male | 0.00 | 0.01 | 0.00 | *** | 0.01 | |
| Age | (years) | 0.00 | 0.00 | -0.01 | * | 0.00 | |
| Education level | Middle school | -0.06 | *** | 0.02 | -0.04 | ** | 0.02 |
| (no or primary education) | High school | 0.11 | *** | 0.01 | 0.14 | *** | 0.01 |
| College or higher | 0.38 | *** | 0.01 | 0.42 | *** | 0.01 | |
| Marital status | Currently married | 0.46 | *** | 0.01 | 0.51 | *** | 0.01 |
| (never-married) | Ever-married | 0.11 | *** | 0.02 | 0.15 | *** | 0.02 |
| Live alone (yes) | No | 0.14 | *** | 0.01 | 0.13 | *** | 0.01 |
| Employment status | Self-employed | -0.05 | *** | 0.01 | -0.04 | *** | 0.01 |
| (economically inactive) | Salaried | 0.03 | ** | 0.01 | 0.03 | *** | 0.01 |
| Log household income | (10,000 won) | -0.02 | *** | 0.00 | -0.02 | *** | 0.00 |
| Subjective health status | Very healthy | 2.43 | *** | 0.03 | 2.43 | *** | 0.03 |
| (very unhealthy) | Healthy | 1.96 | *** | 0.02 | 1.95 | *** | 0.02 |
| Neutral | 1.37 | *** | 0.02 | 1.36 | *** | 0.02 | |
| Unhealthy | 0.77 | *** | 0.02 | 0.77 | *** | 0.02 | |
| Contact frequency with relative/family (<1/month) | 1/month | 0.20 | *** | 0.01 | 0.14 | *** | 0.03 |
| 2–3/month | 0.28 | *** | 0.01 | 0.21 | *** | 0.03 | |
| 1/week | 0.30 | *** | 0.01 | 0.11 | *** | 0.04 | |
| 2–3/week | 0.32 | *** | 0.01 | 0.07 | ** | 0.04 | |
| ≥4/week | 0.38 | *** | 0.01 | 0.05 | * | 0.03 | |
| Contact frequency with neighbor | 1/month | 0.13 | *** | 0.01 | 0.10 | *** | 0.04 |
| (<1/month) | 2–3/month | 0.11 | *** | 0.01 | 0.05 | *** | 0.04 |
| 1/week | 0.14 | *** | 0.01 | 0.11 | ** | 0.04 | |
| 2–3/week | 0.18 | *** | 0.01 | 0.07 | ** | 0.04 | |
| ≥4/week | 0.29 | *** | 0.01 | -0.06 | * | 0.03 | |
| Contact frequency with friend | 1/month | 0.15 | *** | 0.01 | 0.09 | * | 0.04 |
| (<1/month) | 2–3/month | 0.21 | *** | 0.01 | 0.18 | *** | 0.04 |
| 1/week | 0.26 | *** | 0.01 | 0.21 | *** | 0.04 | |
| 2–3/week | 0.30 | *** | 0.01 | 0.34 | *** | 0.04 | |
| ≥4/week | 0.41 | *** | 0.01 | 0.54 | *** | 0.03 | |
| Age*contact frequency with relative/family (<1/month) | 1/month | 0.00 | * | 0.00 | |||
| 2–3/month | 0.00 | * | 0.00 | ||||
| 1/week | 0.00 | *** | 0.00 | ||||
| 2–3/week | 0.01 | *** | 0.00 | ||||
| ≥4/week | 0.01 | *** | 0.00 | ||||
| Age*contact frequency with neighbor (<1/month) | 1/month | 0.00 | 0.00 | ||||
| 2–3/month | 0.00 | * | 0.00 | ||||
| 1/week | 0.00 | 0.00 | |||||
| 2–3/week | 0.00 | *** | 0.00 | ||||
| ≥4/week | 0.01 | *** | 0.00 | ||||
| Age*contact frequency with friend (<1/month) | 1/month | 0.00 | 0.00 | ||||
| 2–3/month | 0.00 | 0.00 | |||||
| 1/week | 0.00 | 0.00 | |||||
| 2–3/week | 0.00 | 0.00 | |||||
| ≥4/week | 0.00 | *** | 0.00 | ||||
| Constant | 4.46 | 4.61 | |||||
| Observations | 221,187 | 22,187 | |||||
| R2 | 0.154 | 0.155 | |||||
* p<0.05
** p<0.01
*** p<0.001