Early-life nutritional additives, household environment, and air pollution in relation to childhood food allergies: A multi-city mother-child study in China.

BACKGROUND

Nutritional supplements and environments have been linked with food allergy (FA), but little research has explored their interactions on children's FA.

OBJECTIVES

To explore the associations between early-life nutritional supplements, household environmental factors (HEFs), and outdoor air pollutant (OAP) exposures, and their interactions on children's FAs.

METHODS

We collected 20,730 surveyed questionnaires from five Chinese cities, covering data on individual characteristics, health outcomes, and HEFs. Multilevel logistic regression models were conducted to establish the impacts of early-life nutritional supplements, HEFs, and OAP exposures on children's FAs.

RESULTS

Children's FA was negatively associated with maternal intake of iron, vitamins A-E, cod-liver oil, docosahexaenoic acid (DHA), protein powder, and prebiotic/probiotics/synbiotics during pregnancy, as well as childhood intake of iron, selenium, vitamin A, B, C, E, and cod-liver oil. Childhood intake of vitamin D and prebiotic/probiotics/synbiotics increased FA risk. Using ceramic tile/stone/cement floor, silicone rubber baby bottle, and fresh air filter reduced FA risk. Conversely, using glass baby bottle, plastic toy, air conditioning in summer, and mosquitos increased FA risk. FA was consistently positively associated with NO2 exposure within the first trimester, while not consistently related with other pollutants in different models. Maternal and childhood intake of nutritional supplements mitigated adverse impacts of HEFs and OAP exposure on FA, while amplifying protective effects, indicating a nutrition-pollution interaction.

CONCLUSIONS

Early-life nutritional supplements, HEFs, and OAP exposures separately and jointly influence children's FA. However, the possibility of false positives due to multiple testing cannot be excluded, which should be interpreted with caution pending replication.