BMI and Chronic Allergic Rhinitis Severity
Based on the most recent and highest quality evidence, BMI does appear to affect chronic allergic rhinitis severity, with obesity associated with worse symptom scores and medication requirements, though the relationship is complex and may not affect disease incidence.
Impact on Disease Severity
The strongest evidence for BMI affecting allergic rhinitis severity comes from a 2018 study in Chinese obese children, which demonstrated:
- Obese children with allergic rhinitis had significantly higher symptom scores (9.5 ± 3.1 vs 8.2 ± 3.5, P < .05) and medication scores (3.6 ± 1.6 vs 2.9 ± 1.8, P < .05) compared to non-obese children with allergic rhinitis 1
- Serum leptin concentration was significantly correlated with increased TH2 cytokines, TH17 cytokines, and altered regulatory T-cell cytokines, suggesting obesity exacerbates inflammation in allergic rhinitis 1
Additional supporting evidence shows:
- A 2009 study found BMI values were significantly higher in patients with moderate-severe persistent allergic rhinitis compared to controls (P=0.0002), and demonstrated a significant relationship between BMI categories and bronchial hyperreactivity in rhinitis patients (P<0.01) 2
- A large 2013 cross-sectional analysis of 17.6 million U.S. adults found obesity was associated with increased odds of allergic rhinitis (adjusted OR = 1.22, P < .001), with increasing BMI as a continuous variable significantly associated with allergic rhinitis presence (OR = 1.023, P < .001) 3
Impact on Treatment Response
Obesity appears to impair the anti-inflammatory response to nasal corticosteroid treatment, though clinical symptom improvement remains similar:
- A 2024 study comparing obese versus normal weight patients treated with nasal beclomethasone found both groups showed similar improvement in symptom scores (VAS, SNOT-22, NOSE-5) and peak nasal inspiratory volumes 4
- However, obese patients demonstrated impaired anti-inflammatory cytokine response, particularly with altered IL-10 behavior, suggesting obesity affects the underlying inflammatory mechanisms despite similar symptomatic relief 4
Contradictory Evidence on Disease Association
The most recent 2025 meta-analysis challenges the association between BMI and allergic rhinitis incidence:
- This systematic review of 32 studies comprising over 2 million participants found no significant association between obesity and allergic rhinitis in either children (OR = 0.99,95% CI = 0.96-1.03) or adults (OR = 1.11,95% CI = 0.92-1.33) 5
- Similarly, overweight status showed no association with allergic rhinitis in children or adults 5
- The certainty of evidence was rated as very low to low using GRADE criteria 5
Clinical Implications
The divergence between studies suggests BMI may not affect whether someone develops allergic rhinitis, but does appear to worsen disease severity and inflammatory burden once present:
- For patients with established allergic rhinitis, higher BMI correlates with worse symptoms and increased medication requirements 1
- Obese patients may require more aggressive symptom management despite similar clinical response to standard nasal corticosteroid therapy 4
- The inflammatory profile differs in obese patients with allergic rhinitis, with elevated leptin driving enhanced TH2 and TH17 inflammation 1
Common Pitfalls
- Do not assume obesity prevents effective treatment—obese patients still respond clinically to nasal corticosteroids, though their inflammatory response may be blunted 4
- Consider that symptom severity assessment may need adjustment in obese patients, as they may require higher medication scores to achieve control 1
- Weight reduction interventions may theoretically improve allergic rhinitis severity given the leptin-inflammation connection, though prospective studies are needed 5, 1