# Airborne Ragweed (Ambrosia artemisiifolia) Allergen Exposure and Sensitization Pattern in Western Romania: A 5-Year Retrospective Cross-Sectional Observational Analysis of Sensitization Prevalence, Complemented by a Parallel Temporal Analysis of Aerobiological Data and Symptom-Driven Healthcare Presentation Patterns Study

## TL;DR

This study in western Romania shows that ragweed allergy is a growing health issue, with many people being sensitized to ragweed pollen and other allergens, and symptoms peaking during ragweed pollen season.

## Contribution

The study integrates aerobiological data with clinical and healthcare presentation patterns to reveal ragweed sensitization trends and their seasonal impact in a specific region.

## Key findings

- 24.1% of patients were sensitized to ragweed, with most being polysensitized to other aeroallergens.
- Ragweed sensitization diagnoses peaked seasonally between mid-August and late September, matching pollen concentrations.
- Polysensitization decreased with age, and clinical manifestations varied by sensitization profile.

## Abstract

Ragweed (Ambrosia artemisiifolia) represents a major and expanding source of aeroallergen exposure in Europe, with rising sensitization rates and substantial clinical impact. However, population-level data integrating airborne pollen exposure with detailed clinical sensitization patterns remain limited. We conducted a 5-year retrospective cross-sectional observational analysis of sensitization prevalence, complemented by a parallel temporal analysis of aerobiological data and symptom-driven healthcare presentation patterns (2020–2024) in Timisoara, Romania, including all patients undergoing first-time sensitization evaluation at a tertiary referral hospital. Sensitization was assessed using standardized skin prick testing to common aeroallergens and other allergen categories, while airborne ragweed pollen concentrations were monitored through a peri-urban network of real-time bio-particle analyzers. Statistical analyses included descriptive statistics, multivariable logistic regression, χ2 tests for co-sensitization patterns, and comparative analyses of clinical manifestations across sensitization profiles. Among 4404 eligible patients, 50.7% were sensitized to at least one allergen. Ragweed sensitization was identified in 24.1% of patients, with a mean age of 31.1 years at diagnosis and no significant sex-related difference. Most ragweed-sensitized patients were polysensitized (71.5%), predominantly to other aeroallergens. Increasing age was independently associated with lower odds of polysensitization to other aeroallergens (adjusted OR = 0.97 per year, 95% CI: 0.96–0.98), while sex showed no independent association. Patients with ragweed sensitization alone and those cosensitized with aeroallergens exhibited similar prevalence of respiratory manifestations, whereas individuals with additional non-aeroallergen sensitization showed lower prevalence of rhinitis, conjunctivitis, and asthma but slightly higher rates of asthma exacerbations. Weekly diagnoses of ragweed sensitization demonstrated a pronounced seasonal peak between calendar weeks 33 and 38 (mid-August to late September), coinciding with peak airborne ragweed pollen concentrations. Ragweed sensitization therefore represents a substantial and seasonally driven healthcare burden in western Romania, characterized by frequent polysensitization, distinct clinical manifestation patterns across sensitization profiles, and close temporal alignment between airborne pollen exposure and clinical presentation. Integrating aerobiological monitoring with clinical surveillance may support targeted prevention strategies and improved patient management.