Background

In recent years, growing attention has been given to the potential health impact of micro- and nano-plastics (MNPs). MNPs originates from various sources, including plastic packaging, personal care products and synthetic clothing. MNPs have been detected in bottled water, fishes, seafood, and various processed foods. MNPs have also been detected in the air, where they contribute to ambient particulate matter, thereby representing another exposure pathway through inhalation. Emerging evidence suggests that elevated concentrations of MNPs in the environment and diet may contribute to an increased risk of allergy. The objective of this study is to assess the influence of exposure to MNPs via diet, lifestyle, and air pollution on the risk of allergic sensitization in the Croatian children population.

Methods

A total of 1,155 children, aged 6 to 18 years, were recruited from three regions in Croatia: Zagreb, Dalmatia, and Slavonia.

Sensitization to allergens was assessed using skin prick tests (SPT), and a binary variable was created using a sensitization index cut-off of 0.6. Exposure to MNPs was assessed using the validated Food Frequency Questionnaire, along with two study-specific questionnaires focusing on MNPs exposure through consumption habits, lifestyle and environmental characteristics. Familial factors were obtained from the validated ISAAC questionnaire. Air pollution exposure was assessed using the average PM10 levels from the two weeks preceding the SPT.

Over 489 variables were collected. Missing data were handled using multiple imputation by chained equations. Variable selection was guided by expert input and Multiple Correspondence Analysis. To reduce data dimensionality, clustering analysis was applied separately to two groups of MNPs indicators: (1) related to lifestyle and consumption habits and (2) related to nutritional habits. A multivariate logistic regression model was then used to assess the association between MNPs exposure clusters, PM10, and allergic sensitization, adjusting for socio-economic factors, allergic family history, pet ownership, BMI, breast feeding, region and urbanicity.

Results

44.6% of participants showed sensitization to at least one allergens.

Three clusters were identified for MNPs exposure and nutritional habits, reflecting distinct behavioural profiles. No significant associations were found between MNPs exposure clusters and sensitization. However, one food consumption cluster—characterized by high intake of diverse food types—was associated with an increased risk of sensitization. PM10 levels showed a negative association with sensitization.

Conclusion

Initial analyses did not demonstrate a significant link between MNPs exposure and allergic sensitization. Alternative modelling approaches, such as penalized regression, are being explored for further analysis