Table 5.

Univariate random effects meta-regression (methods of moments) and subgroup analyses for MARITAL STATUS (married/partnered)

			Subgroup analyses				Results from meta-regression
			Results		Heterogeneity
Variable	Subgroup	Number of studies	OR	95% CI	P-value	I 2	Coefficient	SD	P-value
Outcome measurement	Mixed	1	1.124	0.682–1.853	N.A.	N.A.	Reference
	Formal	9 (14 different samples)	1.053	0.931–1.192	0.001	62%	−0.0650	0.3067	0.832
Proportion of volunteers (%) in baseline study sample	Continuous	9a (14 different samples)	1.087	0.968–1.221	0.045	43%	− 0.0002	0.0002	0.385
	0–100%	8 (9 different samples)	1.071	0.917–1.250	0.001	70%	Reference
	0%	2 (3 different samples)	1.052	0.902–1.227	0.381	0%	0.0468	0.1907	0.806
	100%	2 (3 different samples)	1.080	0.564–2.066	0.175	43%	−0.1253	0.2095	0.550
Mean age at baseline	Continuous	8b (12 different samples)	1.147	1.001–1.315	0.112	35%	− 0.0008	0.0004	0.030
	≤ 55 years	6 (8 different samples)	1.140	0.911–1.427	0.000	76%	Reference
	>  55 years	5 (7 different samples)	0.999	0.913–1.092	0.539	0%	−0.1477	0.1419	0.300
Continent	USA	4	1.065	0.870–1.304	0.049	62%	Reference
	Europe	6 (11 different samples)	1.054	0.904–1.230	0.009	57%	−0.0106	0.1314	0.936
Year of baseline measurement	Continuous	10 (15 different samples)	1.055	0.937–1.188	0.002	59%	0.0088	0.0096	0.361
	<  2006	8 (11 different samples)	1.055	0.928–1.199	0.000	69%	Reference
	≥ 2006	3 (4 different samples)	1.081	0.742–1.575	0.522	0%	0.0295	0.2251	0.896
Duration of follow-up	Continuous	10 (15 different samples)	1.055	0.937–1.188	0.002	59%	−0.0111	0.0115	0.335
	≤ 3 years	3 (7 different samples)	0.990	0.830–1.180	0.274	20%	Reference
	4–7 years	2	1.096	0.822–1.463	0.905	0%	0.0776	0.2315	0.737
	≥ 8 years	5 (6 different samples)	1.082	0.896–1.306	0.000	81%	0.0580	0.1499	0.699
Risk of bias items
Study participation	Unclear/high risk of bias	9 (12 different samples)	1.004	0.897–1.124	0.019	52%	Reference
	Low risk of bias	2 (3 different samples)	1.353	1.105–1.657	0.478	0%	0.3106	0.1563	0.047
Study confounding	Unclear/high risk of bias	2	0.846	0.766–0.935	0.763	0%	Reference
	Low risk of bias	8 (13 different samples)	1.115	0.994–1.252	0.083	38%	0.2803	0.1113	0.012

^aThe study of Bartels et al. (2013) is not included in this analysis, because the proportion of volunteers (%) in the baseline study sample is not reported

^bThe studies of Bartels et al. (2013) and Hank & Erlinghagen (2010) are not included in this analysis, because the mean age at baseline is not reported