The effect of non-participation on the prevalence of food insecurity in a population-based cohort in Portugal.

Abstract

Non-participation can be a source of selection bias. We evaluated the effect of non-participation on food insecurity prevalence among 2942 young adults from the EPITeen cohort (Portugal), which we have followed since assembling the cohort in 2003-2004. We conducted a cross-sectional study when the cohort participants were 26years old. To examine the effect of non-participation, we statistically imputed the missing data on food security status using multivariate imputation by chained equations based on characteristics associated with food insecurity, specifically household income perception, education and household structure from 21 or 24years of age follow-ups. In our cohort, non-participation caused ~ 2% difference in the food insecurity prevalence: 11.0% (95% CI 9.0-13.0) for 954 participants and 12.6% (95% CI 11.1-14.1) after imputation. These estimates are close to evidence from other European countries and sustain the relevance of developing public health interventions to promote food security, especially considering the negative nutritional and health outcomes associated with food insecurity.