Table 2.

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).