The prevalence of obesity and underweight in celiac patients at the time of diagnosis: a systematic review and meta-analysis.

Background: This study aimed to estimate the prevalence of obesity, overweight, and underweight in celiac disease (CD) at diagnosis before starting the Gluten-free diet (GFD).

Methods: A comprehensive search was conducted in PubMed, Embase, Scopus, and Web of Science until July 2024 to find the cross-sectional and longitudinal studies that measured the body mass index (BMI) in CD patients at diagnosis. The risk of bias assessment was conducted using the Newcastle-Ottawa Quality Assessment scale. Meta-regression analyses were applied to understand whether weight status is associated with CD.

Results: A total of 23 studies involving 15,299 CD patients and 815,167 healthy individuals were included in this study. In newly diagnosed CD patients, pooled estimates of the prevalence of obesity, overweight, and underweight before GFD were 11.78%, 18.42%, and 11.04%, respectively. The prevalence of overweight and obesity in newly diagnosed CD patients increased from 22.15% in 2003-2009 to 32.51% in 2016-2021. Meta-regression analyses indicated that the CD patients with higher BMI had a higher mean age (p = 0.001), and female gender had a marginally significant (p = 0.055) association with higher BMI. Only a few CD patients were underweight at the time of diagnosis, and more patients were overweight/obese.

Conclusions: our meta-analysis demonstrated that only a few CD patients were underweight at the time of diagnosis, and almost 37% were overweight or obese. Meta-regression showed a significant association between higher BMI and higher mean age and female gender. A delay or failure for diagnosis of CD is more common in overweight/obese patients, resulting in more progression of the disease and counteracting any advantages of diagnosis.