Vegetarian diet has a protective effect against diabetes risk

Objectives:
Does a vegetarian diet reduce diabetes risk?

Study design:
This review article included 2 cohort studies and 12 cross-sectional studies.

Although the funnel plot showed a slight asymmetry, publication bias was not detected based on statistical tests such as the Egger’s [p = 0.465] and Begg’s tests [p = 0.584].

Results and conclusions:
The investigators found vegetarians had a 27.4% lower risk of having diabetes than omnivores [OR = 0.726, 95% CI = 0.608-0.867].

The investigators found in the subgroup analyses by sex, study design, region of study and vegetarian type, the pooled OR of all subtotal estimates suggested that vegetarians had a lower prevalence or incidence of diabetes than omnivores. Vegetarian men were less likely to have diabetes than their omnivorous counterparts; in contrast, no such significant association was found in women.

The investigators found in the subgroup analysis, the inverse association between a vegetarian diet and diabetes incidence/prevalence tended to be stronger for the 3 studies conducted in the Western Pacific region [OR = 0.514, 95% CI = 0.304-0.871] and the 7 studies performed in Europe & North America [OR = 0.756, 95% CI = 0.589-0.971] than for the 4 studies conducted in Southeast Asia [OR = 0.888, 95% CI = 0.718-1.099].

The investigators found in the subgroup analysis by types of vegetarianism, most types (vegan, lacto- and lacto-ovo-vegetarians) were significantly associated with a lower prevalence or incidence of diabetes than omnivorous participants, except for pesco-vegetarians.

The investigators found the influence analysis showed that the pooled OR was not dramatically changed when it was recalculated after dropping one study at a time. In other words, no one study had a substantial impact on the pooled effect size; this is indicative of a statistically robust result.

The investigators concluded that a vegetarian diet has a protective effect against diabetes risk. However, well-designed prospective cohort studies from various countries that obtain information on the participants’ motivations for vegetarianism, the duration of adherence to a vegetarian diet and verification of a vegetarian diet are needed to strengthen these findings.

Original title:
Adherence to a Vegetarian Diet and Diabetes Risk: A Systematic Review and Meta-Analysis of Observational Studies by Lee Y and Park K.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5490582/

Additional information of El Mondo:
Find more information/studies on vegetarianism and diabetes right here.