Brazilian Vegetarian Population-Influence of Type of Diet, Motivation and Sociodemographic Variables on Quality of Life Measured by Specific Tool (VEGQOL)

The adoption of a vegetarian diet has been associated with positive health outcomes. However, few studies evaluate the effect of this eating pattern on quality of life. Moreover, no specific instrument for the vegetarian population to measure the quality of life is available worldwide. Therefore, this study aimed to elaborate and validate a specific questionnaire to measure the quality of life in vegetarians. The Specific Vegetarian Quality of Life Questionnaire (VEGQOL) was constructed based on other instruments and studies related to vegetarianism. The content and semantic validation were performed by a group of experts, followed by a pilot study to evaluate the questionnaire acceptability and reproducibility. Discriminant validation was tested using the WHOQOL as the gold standard measure (Pearson correlation ranging from 0.302 of the domain 3 to 0.392 of the domain 2). Afterward, a nationwide survey was conducted using VEGQOL. Content and semantic validation selected 19 of the initial 30 items. VEGQOL presented good reproducibility (Cohen's Kappa coefficient ranging from 0.361 to 0.730 and intraclass correlation coefficient of 0.820) and internal consistency (0.708), both adequate to evaluate the quality of life in vegetarians. The sample size (n = 5014 individuals, error of 3% at a level of significance of 5%) and distribution was representative of the Brazilian vegetarian population. In general, the quality of life of Brazilian vegetarians was considered satisfactory (VEGQOL cut off points 70-80). Among different types of vegetarians, the vegans showed better results with a VEGQOL mean value of 79.2 +/- 10.7. Older individuals, the ones who adopted the diet for a longer time (VEGQOL mean value of 75.8 +/- 12.7) and the ones who had other vegetarians in their social network (VEGQOL mean value of 74.6 +/- 12.2) also had a better quality of life score. Individuals who adopted it for ethical or health reasons had a higher quality of life score. The questionnaire produced in this study is a useful tool for future research in this area. Results were better for vegans and for the ones who adopt the diet for ethical or health reasons.