Vegetarian diets and incidence of diabetes in the Adventist Health Study-2
Nutrition, Metabolism & Cardiovascular Diseases, 10/19/2011

Tonstad S et al. – Vegetarian diets (vegan, lacto ovo, semi–) were associated with a substantial and independent reduction in diabetes incidence. In Blacks the dimension of the protection associated with vegetarian diets was as great as the excess risk associated with Black ethnicity.

• Participants were 15,200 men and 26,187 women (17.3% Blacks) across the U.S. and Canada who were free of diabetes and who provided demographic, anthropometric, lifestyle and dietary data.
• Participants were grouped as vegan, lacto ovo vegetarian, pesco vegetarian, semi–vegetarian or non–vegetarian (reference group).
• A follow–up questionnaire after two years elicited information on the development of diabetes.
• Cases of diabetes developed in 0.54% of vegans, 1.08% of lacto ovo vegetarians, 1.29% of pesco vegetarians, 0.92% of semi–vegetarians and 2.12% of non–vegetarians.
• Blacks had an increased risk compared to non–Blacks (odds ratio [OR] 1.364; 95% confidence interval [CI], 1.093–1.702).

• In multiple logistic regression analysis controlling for age, gender, education, income, television watching, physical activity, sleep, alcohol use, smoking and BMI, vegans (OR 0.381; 95% CI 0.236–0.617), lacto ovo vegetarians (OR 0.618; 95% CI 0.503–0.760) and semi–vegetarians (OR 0.486, 95% CI 0.312–0.755) had a lower risk of diabetes than non–vegetarians.
• In non–Blacks vegan, lacto ovo and semi–vegetarian diets were protective against diabetes (OR 0.429, 95% CI 0.249–0.740; OR 0.684, 95% CI 0.542–0.862; OR 0.501, 95% CI 0.303–0.827); among Blacks vegan and lacto ovo vegetarian diets were protective (OR 0.304, 95% CI 0.110–0.842; OR 0.472, 95% CI 0.270–0.825).
• These associations were strengthened when BMI was removed from the analyses.