Prevalence ratios and 95% CIs of frequency of laughing according to equivalised income
| Equivalised income* | |||||
| Q1 | Q2 | Q3 | Q4 | P for trend† | |
| Men | |||||
| Number of participants | 2628 | 2454 | 2739 | 2480 | |
| Number of participants laughing almost every day | 812 | 866 | 1060 | 1096 | |
| Crude | Reference | 1.14 (1.06–1.24) | 1.25 (1.16–1.35) | 1.43 (1.33–1.54) | <0.0001 |
| Age adjusted | Reference | 1.13 (1.05–1.22) | 1.25 (1.16–1.34) | 1.43 (1.33–1.54) | <0.0001 |
| Multiadjusted model 1‡ | Reference | 1.04 (0.96–1.13) | 1.12 (1.04–1.21) | 1.24 (1.16–1.34) | <0.0001 |
| Multiadjusted model 2§ | Reference | 1.03 (0.96–1.11) | 1.12 (1.05–1.21) | 1.21 (1.13–1.30) | <0.0001 |
| Women | |||||
| Number of of participants | 2688 | 2169 | 2863 | 2731 | |
| Number of participants laughing almost every day | 1126 | 879 | 1462 | 1507 | |
| Crude | Reference | 0.97 (0.90–1.04) | 1.22 (1.15–1.29) | 1.32 (1.25–1.39) | <0.0001 |
| Age adjusted | Reference | 0.96 (0.89–1.02) | 1.19 (1.13–1.26) | 1.30 (1.23–1.38) | <0.0001 |
| Multiadjusted model 1 | Reference | 0.92 (0.86–0.99) | 1.09 (1.03–1.15) | 1.16 (1.10–1.23) | <0.0001 |
| Multiadjusted model 2 | Reference | 0.98 (0.92–1.05) | 1.06 (1.00–1.12) | 1.14 (1.08–1.20) | <0.0001 |
*Q1 (men; <€12 041, women; <€9518), Q2 (men; €12 041–€15 543, women; €9518–€14 957), Q3 (men; €15 544–€24 426, women; €14 958–€21 153), Q4 (men; ≥€24 427, women; ≥€21 154).
†P for trend was calculated by categorical variables.
‡Model 1 is adjusted for age (5 years category), instrumental activities of daily living (independent, not independent, missing), depression (no depression, depression, missing).
§Model 2 is adjusted for the covariates in model 1 plus frequency of meeting friends (<2 times/week, ≥2 times/week, missing), number of social groups (0, 1 or 2, ≥3, missing), family structure (alone, ≥2 without partner, ≥2 with partner, missing).