Fruit and vegetable intake and type 2 diabetes: EPIC-InterAct prospective study and meta-analysis

Abstract

Fruit and vegetable intake (FVI) may reduce the risk of type 2 diabetes (T2D), but the epidemiological evidence is inconclusive. The aim of this study is to examine the prospective association of FVI with T2D and conduct an updated meta-analysis. In the European Prospective Investigation into Cancer-InterAct (EPIC-InterAct) prospective case-cohort study nested within eight European countries, a representative sample of 16,154 participants and 12,403 incident cases of T2D were identified from 340,234 individuals with 3.99 million person-years of follow-up. For the meta-analysis we identified prospective studies on FVI and T2D risk by systematic searches of MEDLINE and EMBASE until April 2011. In EPIC-InterAct, estimated FVI by dietary questionnaires varied more than twofold between countries. In adjusted analyses the hazard ratio (95% confidence interval) comparing the highest with lowest quartile of reported intake was 0.90 (0.80-1.01) for FVI; 0.89 (0.76-1.04) for fruit and 0.94 (0.84-1.05) for vegetables. Among FV subtypes, only root vegetables were inversely associated with diabetes 0.87 (0.77-0.99). In meta-analysis using pooled data from five studies including EPIC-InterAct, comparing the highest with lowest category for FVI was associated with a lower relative risk of diabetes (0.93 (0.87-1.00)). Fruit or vegetables separately were not associated with diabetes. Among FV subtypes, only green leafy vegetable (GLV) intake (relative risk: 0.84 (0.74-0.94)) was inversely associated with diabetes. Subtypes of vegetables, such as root vegetables or GLVs may be beneficial for the prevention of diabetes, while total FVI may exert a weaker overall effect.

Figure 1

Flow diagram of the selection of prospective studies of fruit and vegetable intake and risk of type 2 diabetes through systematic review of the literature

Figure 2

Hazard ratio of type 2 diabetes comparing the highest with the lowest quartile of estimated total fruit and vegetable intake across countries: EPIC-InterAct study * * Model with age as the underlying timescale and adjusted for centre, sex, education level, BMI, physical activity level, smoking status, total energy intake, and alcohol intake. Square sizes are proportional to weight of each country

Figure 3

Relative risk of type 2 diabetes for the middle and highest estimated intake categories of fruit and vegetables versus the reference intake category: meta-analysis results M=medium category relative to the reference category, H=high category relative to the reference category.