Qian F, et al. – In this study, researchers determined the role of plant-based dietary patterns in the primary prevention of type 2 diabetes among adults via quantitatively synthesizing available prospective observational evidence on this association. According to findings, greater adherence to plant-based dietary patterns was linked to a lower risk of type 2 diabetes, and this link was strengthened when healthy plant-based foods were included in the pattern. These findings were consistent across multiple prespecified subgroups and in sensitivity analyses.

Methods

• Investigators searched PubMed and MEDLINE, Embase, Web of Science, and reference lists for relevant studies through February 15, 2019, and conducted data analyses between December 2018 and February 2019.
• Eligible studies evaluated the incidence of type 2 diabetes among adults in relation to adherence to plant-based dietary patterns.
• Meta-analysis of Observational Studies in Epidemiology guidelines were used for data abstraction and reporting, and a National Heart, Lung, and Blood Institute evaluation tool was used to assess study quality.
• Full-text evaluations and data abstraction was independently performed by two authors.
• The investigators calculated the overall relative risk (RR) and 95% CI using the random-effects method in the meta-analysis.
• The main outcomes and measures included level of adherence to a plant-based diet and incidence of type 2 diabetes.

Results

• In all, 9 studies representing 307,099 participants and 23,544 cases of incident type 2 diabetes were included.
• The researchers noted a significant inverse link between higher adherence to a plant-based dietary pattern and the risk of type 2 diabetes (RR: 0.77; 95% CI: 0.71-0.84) vs poorer adherence, with modest heterogeneity across studies (I² = 44.5%; P = 0.07 for heterogeneity).
• The use of fixed-effects model also generated similar results (RR: 0.80; 95% CI: 0.75-0.84).
• The inclusion of healthy plant-based foods, such as fruits, vegetables, whole grains, legumes, and nuts in the definition of “plant-based patterns” further supported this association (RR: 0.70; 95% CI: 0.62-0.79).
• When it comes to dietary evaluation, disease outcomes, and statistical adjustment for confounding factors, they noted that most studies were of good quality.
• Findings revealed a significant inverse linear dose-response link between plant-based dietary indices and risk of type 2 diabetes, when restricted cubic splines were used.