Table 4.

Pooled odds ratios and corresponding 95% confidence intervals for participation levels for specific demographic determinants

determinant		studies (n)*	Pooled OR [95%CI]
sex	(female:male)	20	1.67	[1.25–2.27]
age	(middle:young)	8	0.93	[0.71–1.24]
age	(old:young)	8	0.76	[0.54–1.06]
education	(moderate/high:low)	6	1.04	[0.77–1.40]
income	(high:low)	2	0.86	[0.56–1.31]
ethnicity	(white:other)	9	1.33	[0.91–1.95]
marital status	(married:other)	5	1.25	[1.05–1.48]

* The total number of studies included in this table varies per characteristic. For each demographic characteristic, only studies enabling to calculate OR's and CI's are included.