Objective To investigate the role of language proficiency as determinant of folic acid knowledge and use in a multi-ethnic pregnancy cohort.
Design Prospective cohort study.
Setting and population Pregnant women from Amsterdam attending obstetric care for their first antenatal visit. Number approached: 12 373 women, response rate: 67% (8266 women aged 14–49 years). Ethnicity was based on the country of birth: the Netherlands, Surinam, Antilles, Turkey, Morocco, Ghana, other non-Western and other Western countries.
Main outcome measures Knowledge about and use of folic acid supplements in pregnancy as elicited in a multilingual questionnaire, as well as determinants of these in ethnic groups separately.
Results Both periconceptional folic acid use and knowledge were significantly lower among Ghanaian, Moroccan, Turkish, and other non-Western women than among women born in the Netherlands or other Western countries. Language proficiency in Dutch was a major determinant of knowledge in all the ethnic groups with a mother tongue other than Dutch [adjusted odds ratios (OR): Western 3.2, non-Western (all countries combined) 7.5], while educational attainment was of secondary importance. Knowledge in turn was the strongest determinant of use (adjusted OR: Western 17.4, non-Western 27.0).
Conclusions Periconceptional folic acid supplement use among women born in non-Dutch-speaking non-Western countries is low, reflecting a lack of knowledge that is determined by the inability to speak and understand the language of the country of residence. Measures to tackle this problem include the provision of linguistically appropriate information via ethnic health advisors, and language courses integrating health education for immigrants.