The Effects of Gluten-free Diet on Body Mass Indexes in Adults with Celiac Disease: A Systematic Review and Meta-analysis of Observational Studies.

Abstract

Gluten-free diet (GFD) includes a higher intake of sugars and fats. Previous studies have investigated its effect on body mass index (BMI) in celiac disease (CD) patients but had contradictive conclusions. Thus, we conducted a systematic review and meta-analysis examining the effect of GFD on BMI in CD patients. Systematically, we conducted literature research using Medline, Scopus, and Embase, and we identified 1565 potential studies/abstracts. Only studies of patients with CD under a GFD with recorded BMI before and after dietary intervention were included. Subgroup analyses based on study design and BMI categories were performed. We calculated the pooled odds ratios (ORs) and 95% confidence intervals (Cls) for the number of patients in each BMI group according to the World Health Organization (WHO) definitions after GFD using fixed and random effect meta-analysis. The analysis included 10 studies and 38 sub-studies/data sets, which encompassed 2450 patients from 5 countries. We found nonsignificant odds for changing the BMI group (pooled OR 0.972, 95% CI: 0.858-1.101, P=0.65) after GFD. However, looking specifically at BMI subgroups, we found higher odds for BMI category change after GFD in underweight patients (OR 0.588, 95% CI: 0.479-0.723, P <0.001), and overweight patients,25<BMI<30, (OR 1.332, 95% CI: 1.167-1.521, P<0.001). No publication bias was demonstrated, and the amount of heterogeneity between studies was moderate (I2=54.13). Although crucial in patients with CD, GFD is associated with increased BMI in some CD patient populations. Accordingly, special considerations and follow-up should be maintained in overweight patients with CD after GFD.