The prevalence of nutritional disorders in inflammatory bowel disease: A systematic review and meta-analysis

The epidemiology of nutritional disorders in inflammatory bowel disease (IBD) remains poorly characterized. Existing evidence is fragmented across specific conditions or confined to single regions, and no study has simultaneously assessed the principal nutritional disorders-malnutrition, overweight or obesity, and sarcopenia-in a unified framework. To address this gap, we systematically searched PubMed, Embase, Cochrane Library, and China Biology Medicine from inception to July 31, 2024 and updated on July 30, 2026. Observational studies reporting prevalence based on standard diagnostic criteria were included. Pooled estimates with 95% confidence interval (CI) and prediction interval (PI) were derived using a random-effects model. Pre-specified subgroup analyses were conducted by sex, age, disease subtype and activity, diagnostic criteria, study setting and gepgraphic variation. Study quality and publication bias were also assessed. After literature screening, 201 studies across 32 countries were included. Underweight affected 11.5% (95% CI: 9.0-14.6%, 95% PI : 1.0-61.7), whereas consensus-based malnutrition [GLIM (Global Leadership Initiative on Malnutrition), ESPEN (European Society for Clinical Nutrition and Metabolism), MNA (Mini Nutritional Assessment), SGA/PG-SGA (Subjective Global Assessment or its variant Patient-Generated SGA) affected 27.6% (95% CI: 20.5-36.1%, 95% PI : 3.6-79.7). Notably, this malnutrition estimate was derived almost exclusively from hospital-based settings (over 80%) and predominantly from a single region. Overweight and obesity affected 23.1% (95% CI : 20.6-25.9, 95%PI : 8.1-50.8) and 13.5% (95%CI : 11.7-15.6, 95%PI : 2.9-44.6), respectively. For muscle depletion, low muscle mass defined by skeletal muscle index was identified in 48.3% (95% CI: 41.8-55.0%, 95% PI : 19.7-78.1), whereas consensus-based sarcopenia [EWGSOP (European Working Group on Sarcopenia in Older People) or AWGS (Asian Working Group on Sarcopenia)] affected 12.6% (95% CI: 6.1-24.2%, 95% PI : 0.9-70.6). Of note, the majority of included studies for malnutrition and sarcopenia were hospital-based. Active disease was associated with significantly higher prevalence of malnutrition. No significant differences were observed between disease subtypes. In conclusion, our findings provide a broad overview of the prevalence of major nutritional disorders in patients with IBD, highlighting that nutritional care in IBD should extend beyond simple weight monitoring. However, given the wide prediction intervals, these pooled estimates should be viewed as averages across highly heterogeneous settings rather than a precise global figure. Future research, particularly population-based studies with standardized diagnostic criteria across diverse regions, is needed to validate our observation.