Yumie Takata

PhD

Oregon State University

Associate Professor

PLCO (Learn more about this study)

PLCO-564

Jan 8, 2020

Vegetarianism and chronic disease risk

Despite the reported health benefits of vegetarian diets, current evidence on vegetarianism and chronic disease risk in population-based studies is limited. Recent meta-analyses reported inverse associations of vegetarian diets and multiple chronic disease outcomes including total cancer incidence and mortality and coronary heart disease incidence and mortality. However, these meta-analyses were based on a small number of studies. From the US, only Adventist cohorts have contributed to these meta-analyses and, to our knowledge, there is no report from other US cohorts on associations between vegetarianism and chronic disease risk. Within the PLCO, dietary patterns were investigated in relation to multiple chronic disease outcomes; however, to our knowledge, no previous PLCO study has examined looked at vegetarianism. Hence, we propose here to investigate associations between vegetarianism and risk of chronic disease in the PLCO population.
We hypothesize that vegetarian diets are associated with decreased risk of multiple chronic disease outcomes such as all-cause and cause-specific mortality and cancer incidence. The PLCO is uniquely suited to test this hypothesis, given that the Diet History Questionnaire (DHQ) collected information on vegetarianism by asking which specific foods participants abstain from. We will use this information to classify participants according to vegetarianism (vegan, pesco-vegetarian, lacto-ovo-vegetarian, lacto-vegetarian, ovo-vegetarian and the others who do not follow any of the aforementioned diets). Regarding chronic disease outcomes, we will include all-cause mortality, cause-specific mortality (cardiovascular disease, coronary heart disease, and cancer) and cancer incidence (all cancers and specific cancer sites as the number allows).
In our statistical analyses, we will run multivariate Cox proportional hazards regression models to estimate risk of each chronic disease outcome as described above by vegetarianism (Aim 1) and conduct stratified analyses (Aim 2).