Prevalence of food allergies in older adults: A systematic review and meta-analysis

Food allergies (FAs) are rising worldwide, but research has mainly focused on younger groups. Older adults may have distinct risk factors (eg, immunosenescence, chronic inflammation, micronutrient deficiencies, multimorbidity, and polypharmacy) that could influence allergic responses. This review aimed to assess FAs prevalence in older adults.

Following PRISMA guidelines, a systematic search across PubMed/Medline, Scopus, Embase, and Web of Science identified studies published up to December 2024. The review planning phase began in July 2023 and included protocol drafting and methodological discussions. No study screening, data extraction, or data analysis was conducted prior to PROSPERO submission and registration (CRD42023445399). Studies reporting FAs prevalence in older adults by all available methods were included. Self-reported and sensitization-based estimates reflect potential FAs, whereas challenge-confirmed FAs represent clinically confirmed allergy. The risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Checklist. Data were pooled using random-effects meta-analyses.

Sixteen studies, involving 33,165 older adults from 11 countries, were included qualitatively, and fourteen were included quantitatively. Most studies were graded as having a moderate risk of bias. The pooled prevalence of self-reported FAs was 12% (95% CI 9-15). Self-reported physician-diagnosed FAs showed a prevalence of 7% (95% CI 5-8). Specific IgE (sIgE) sensitization indicated a prevalence of 14% (95% CI 10-18). Only 1 study reported challenge-confirmed FAs with a prevalence of 0.5%. Exploratory comparisons suggest similar combined prevalence estimates across low- and middle-income countries (LMIC) (10%) and high-income countries (9%), though the small number of LMIC studies and differences in assessment methods preclude firm conclusions. sIgE sensitization to common allergens was 3% for cow's milk and peanut, 2% for egg and 1% for soy.

Older adults show meaningful rates of self-reported food-related symptoms and sensitization. However, the prevalence of clinically confirmed FAs remains poorly defined. The limited evidence and heterogeneity across studies highlight the need for standardized diagnostic criteria and greater inclusion of older adults in future FAs research.

www.crd.york.ac.uk/prospero identifier is CRD42023445399.