Table 3.

Results from logistic regression analysis for preconceptional folic acid knowledge and preconceptional intention to seek for care with “yes, she certainly should” as reference category

	Preconceptional folic acid knowlegdea			Preconceptional intention to seek for careb
	Ic	IIc	IIIc	Ic	IIc
Study years
2007	0.74 (0.63–0.87)**	0.73 (0.61–0.88)**	0.73 (0.61–0.88)**	0.53 (0.40–0.69)**	0.51 (0.39–0.68)**
2009	0.97 (0.82–1.14)	1.00 (0.83–1.19)	0.99 (0.83–1.19)	0.61 (0.47–0.81)**	0.61 (0.46–0.81)**
2010	reference	reference	reference	0.58 (0.44–0.77)**	0.61 (0.46–0.81)**
2011	NA	NA	NA	1.14 (0.86–1.51)	1.19 (0.89–1.59)
2012	NA	NA	NA	1.42 (1.07–1.90)*	1.54 (1.14–2.07)*
2013	NA	NA	NA	1.00 (0.75–1.34)	1.01 (0.75–1.37)
2014	NA	NA	NA	reference	reference
Socio-demographics
Gender (reference: women)
Men		0.42 (0.36–0.49)**	0.42 (0.36–0.49)**		1.41 (1.22–1.64)**
Age in years (reference: 25–44)
16–24		0.31 (0.24–0.40)**	0.30 (0.23–0.39)**		1.38 (1.07–1.79)*
45 and older		0.40 (0.34–0.48)**	0.40 (0.33–0.47)**		1.09 (0.91–1.30)
Ethnicity (reference: Dutch)
Non-Western immigrants		0.57 (0.46–0.71)**	0.45 (0.33–0.62)**		1.94 (1.59–2.35)**
Western immigrants		0.69 (0.53–0.91)*	0.74 (0.44–1.26)		1.59 (1.23–2.05)**
Socio-economic status
Educational level (scale)		1.31 (1.10–1.55)*	1.20 (0.98–1.47)		1.13 (0.94–1.35)
Household income (reference: >2× moderate)
Minimum		0.59 (0.46–0.77)**	0.60 (0.46–0.77)**		1.56 (1.22–2.01)**
Minimum-moderate		0.66 (0.53–0.83)**	0.66 (0.52–0.82)**		1.60 (1.26–2.02)**
Moderate-2× moderate		0.79 (0.65–0.96)*	0.78 (0.64–0.95)*		1.07 (0.87–1.31)
Employment status (reference: employed)
Unemployed		0.93 (0.78–1.10)	0.92 (0.78–1.10)		1.18 (1.00–1.40)
Neighbourhood (reference: deprived)
Non-deprived					0.97 (0.83–1.15)
Other variables
Children living in the household (reference: yes)
No		0.60 (0.51–0.71)**	0.60 (0.51–0.70)**		1.60 (1.36–1.88)**
Religion (reference: yes)
No		1.03 (0.88–1.21)	1.03 (0.87–1.20)		NA
Interaction
Ethnicity*educational level (ref: Dutch* educational level)
Non-Western* educational level			1.46 (1.01–2.11)*
Western* educational level			0.92 (0.50–1.70)

^aPreconceptional folic acid knowledge among respondents answering ‘other’ vs. ‘yes’ on: “A woman who wishes to become pregnant should take folic acid supplementation before she tries to become pregnant”. N = 3766; Rotterdam, the Netherlands, 2007, 2009 and 2010

^bPreconceptional intention to consult a GP or midwife among respondents answering ‘no’ vs. ‘yes’ on: “A woman who wishes to become pregnant should consult a GP or midwife before she tries to become pregnant”. N = 2771; Rotterdam, the Netherlands, 2007, 2009–2014

^cIn model I the study years were entered, in model II socio-demographics, socio-economic status and other variables were included, and in model III the observed interaction between ethnicity and educational level was included

Data are in OR, odds ratio (95 % confidence interval). OR = exp (ß), where ß is the coefficient in the logistic model

* p ≤0.05; ** p ≤0.001

NA Not Accounted

Nagelkerke for preconceptional folic acid knowledge: step I R² = 0.006, step II R² = 0.181, step III R² = 0.181 and for preconceptional intention to seek for care: step I R² = 0.042, step II R² = 0