Prevalence and socio-economic disparities in vegetarianism and flexitarianism over 15 years: the Dutch Lifelines Cohort.

Transitioning to more plant-based diets is crucial for both planetary and human health, and ensuring an equitable transition across all socio-economic groups is also important. However, empirical evidence on the prevalence and socio-economic disparities in vegetarianism and flexitarianism over time in the same population is scarce. This study investigated this in a general Dutch adult population over 15 years. From three general assessments of the Dutch Lifelines study, 143 359 participants from assessment 1 (2006-2013), 100 859 participants from assessment 2 (2013-2017), and 55 282 participants from assessment 3 (2019-2024) were included in this study. The dietary identity was self-reported, collected at each assessment, and categorized into following a vegetarian, flexitarian, other, and no special diet. Socio-economic status was indicated by education attainment. The association between socio-economic status and different dietary identities was estimated using multinomial logistic regression. The prevalence of individuals following vegetarian or flexitarian diet doubled over the three assessment periods, with the proportion of vegetarians and flexitarians increasing from 2.02% to 4.11% and from 3.50% to 7.16%, respectively. Across three assessments, lower education attainment was consistently associated with a lower likelihood of following a vegetarian or flexitarian diet. For example, in assessment 1 individuals with low education attainment were 77% (relative risk ratio [95% CI]: 0.23 [0.20-0.25]) less likely to follow a vegetarian diet compared to those with high education attainment. In a Dutch population cohort, we observed an increasing trend of vegetarian and flexitarian diets over 15 years, along with persistent socio-economic inequalities in these diets.