A Multicenter Pilot Randomized Trial of a Lifestyle Intervention to Prevent Type 2 Diabetes in High-Risk Individuals

Abstract

Background: Type 2 diabetes (T2D) is a growing public health concern, particularly in low- and middle-income countries. Although prediabetes is a major risk factor for T2D, it remains largely underdiagnosed and untreated. Structured lifestyle interventions have proven effective in preventing diabetes, but their feasibility within the Brazilian public health system remains unclear.

Methods: This multicenter pilot randomized controlled trial assessed the feasibility of a culturally adapted lifestyle intervention (PROVEN-DIA) across the five regions of Brazil. A total of 220 adults at high risk for T2D were randomized to an intervention group or a control group (usual care) and followed for three months. Both groups received similar educational content on healthy eating and physical activity, but the intervention group participated in a structured and personalized lifestyle program with regular follow-up sessions. The primary outcome was adherence to dietary recommendations, assessed using the BALANCE Index-a validated dietary score (range: 0-40) based on the Brazilian Cardioprotective Diet that classifies foods into color-coded groups according to nutritional quality-along with engagement in moderate-to-vigorous physical activity (MVPA). Secondary outcomes included diet quality (DQIR), anthropometric and metabolic parameters.

Results: Feasibility was demonstrated by a 93.2% retention rate (n = 205). There was no significant difference in the primary outcome (simultaneous improvement in diet and MVPA). However, the PROVEN-DIA group exhibited significantly greater improvements in diet quality, with a 2.8-point increase in the BALANCE Index (vs. 0.5 in the control, p = 0.03), and a significant improvement in the DQIR (p < 0.001). No significant differences between groups were observed in MVPA, HbA1C, glycaemia, or body weight.

Conclusions: The PROVEN-DIA intervention proved feasible within the Brazilian public health context, resulting in significant improvements in dietary quality among individuals at high risk for T2D. A larger trial with longer follow-up is warranted to evaluate its effectiveness in preventing the progression to diabetes. However, to enhance physical activity outcomes, specific adaptations and targeted strategies may be required to better support participant engagement in exercise.

Keywords: BALANCE program; Brazilian public health; dietary quality; feasibility study; lifestyle intervention; physical activity; randomized controlled trial; type 2 diabetes prevention.

Figure 1

Study flowchart. * Data analysis was based on available case data, but participants lost to follow-up were retained in the statistical analysis according to the intention-to-treat principle.

Figure 2

Changes in dietary quality indicators after the intervention: BALANCE Index and DQIR scores at baseline and 3-month follow-up in the Proven-Dia and UT groups.