Fig 1.
Flow diagram of study selection.
* The list of the 210 articles selected for full text evaluation is available in S1 Table, which also describes the outcome of the selection process for each article (including justification for exclusion). CVD, cardiovascular diseases; T2D, type 2 diabetes.
Table 1.
Characteristics of the eight studies included in the meta-regression analysis on whole grain intake and occurrence of type 2 diabetes.
Fig 2.
Meta-regression analysis between whole grain intake and occurrence of type 2 diabetes.
The dose-response meta-regression analysis between whole grain intake and occurrence of type 2 diabetes (T2D) was performed by using a hierarchical mixed least square linear regression model, with T2D rate (% of cases) as the outcome variable and whole grain intake (in g/d of whole grain ingredients) as the predictor. Each category of whole grain intake was considered as a specific statistical unit (called a “statistical series”). Eight studies were included in the meta-regression analysis. Four of the studies were subdivided into series by quintiles of whole grain consumption, two by quartiles, one by tertiles and one by six arbitrary cut-offs, resulting in 37 analyzed series in total. The size of the circles reflects the number of subjects included in each individual series. See S2 Fig for a semi-log representation. T2D, type 2 diabetes. WG, whole grains.
Table 2.
Bivariate meta-regression analyses performed on whole grain intake and occurrence of type 2 diabetes.