Differential cost-effectiveness of health promotion in the Netherlands requires appropriate and valid measures of health literacy

BACKGROUND Unhealthy lifestyles are much more prevalent in lower socio-economic groups and significantly contribute to socio-economic inequalities in health. Health education is a key element in improving healthy lifestyles and human well-being, but less effective in achieving behaviour change in low socio-economic groups. Inadequate health literacy (HL), referring to the cognitive and social skills that determine the motivation and ability of individuals to gain access to, understand and use information in ways which promote and maintain good health, is an important cause of lower effectiveness and worse cost-effectiveness of health education among low socio-economic groups. The prevalence of inadequate HL in The Netherlands is at least 11%, but most likely much higher. Two-thirds of the individuals with low HL have Dutch as their mother tongue. Inadequate HL causes less responsiveness to untargeted health education, inadequate understanding of written information and poor interactive communication with preventive care givers. It is evident that health education interventions specifically targeted at low HL levels are needed. Therefore, HL needs to be measurable. Internationally, brief and feasible measures of objective HL with adequate reliability and validity have been developed. In The Netherlands we urgently need such measures to enable evaluation of health promotion and other preventive care interventions in low SES groups. We propose to further develop and validate the most commonly used international measures for the Dutch situation. AIM We aim to adapt, test and validate internationally standard HL measures ‘the Newest Vital Sign (NVS)’ and ‘the Short Rapid Estimate of Adult Literacy in Medicine (REALM)’ for objective HL assessment in the Netherlands. The measures will be appropriate, feasible, reliable and valid in the Dutch context, while maintaining international comparability of scores. Specific tasks include: - To adapt and qualitatively test the NVS-US into Dutch (NVS-D) - To adapt the REALM into Dutch (REALM-D) - To collect interview data for quantitative psychometric testing - To analyse feasibility, score distribution, reliability and validity of NVS-D and REALM-D METHODS The NVS was developed originally in the US and makes use of a nutrition label relating to ice cream. In the development of a Dutch NVS, we use the protocol that was applied successfully by Prof. Rowlands to amend the NVS-US to fit in UK nutrition labelling. Specific attention will be paid to potential cross-cultural interpretation problems. The REALM is a word recognition test in a health context. Adaptation into Dutch poses additional requirements because language is part of the object of measurement. We adapt the REALM into Dutch making use of linguistic expertise to maintain comparability with the US original. Replacements will be chosen from Dutch health promotion materials. The NVS-D and REALM-D will be quantitatively tested using data from 400 interviews. Data will be collected at the outpatient clinic (n=300) and in the general population (n=100). Mastery of Dutch among subjects whose mother tongue is not Dutch is measured as a potential determinant of HL. Standard analyses will be performed to assess psychometric characteristics of the REALM-D and NVS-D. Comparison of score patterns with the originals and UK adaptations provides insight in cross-national comparability of scores, and we will propose norm scores for the REALM-D and NVS-D. DELIVERABLES We will deliver valid Dutch versions of internationally accepted measures of objective HL that are feasible for use in evaluation of health promotion and other health interventions, and in further HL research in The Netherlands. Expected usage includes measurement of HL as a determinant of the differential (cost-) effectiveness of health promotion in low SES groups; development of targeted interventions to improve the effects of health education in low SES groups and to measure their effectiveness; and further development of empirical HL research in the Netherlands. Complementary to the European Health Literacy Survey (HLS-EU), this work is essential to bring Dutch HL research in line with international standards.