Background Many countries have recorded the trends of food allergy (FA) prevalence. Little is known about epidemiologic trends of childhood FA in China. Methods In three cross‐sectional surveys conducted in 1999, 2009, and 2019, the prevalence of and characteristic changes in FA in children aged ≤ 2 years were assessed and the outcomes were compared. All the children were recruited during well‐baby check‐ups at the Children's Hospital of Chongqing Medical University. All participants had a detailed medical history taken and underwent skin prick tests using ten commercial food extracts. Open food challenges were used for confirmation of FA. Results The three studies included 1228 children (314 in 1999, 401 in 2009, and 513 in 2019; response rate > 95%). The prevalence of FA in 2009 (7.7%) and 2019 (11.1%) was significantly higher than that in 1999 (3.5%). However, there was no statistically significant difference in prevalence between 2009 and 2019 (P = .086). There was evidence of increased prevalence in CMPA between 1999 and 2019 (1.6% versus 5.7%; P = .004). However, no statistic difference was found in egg allergy (2.9% versus 5.5%; P = .21). The incidence of skin symptoms did not differ significantly over the study period, while the incidence of gastrointestinal symptoms increased significantly (18.2% in 1999, 12.9% in 2009, and 43.9% in 2019; P < .05). Conclusions The prevalence of FA in children rapidly increased after the 1990s and gradually stabilized after 2010. Cow's milk has become the most common food allergen among children in Chongqing. The incidence of gastrointestinal symptoms as a manifestation of FA has increased significantly since 2010.

ObjectiveFamily history of atopic diseases (FHA) contributes to food allergy (FA). But little is known whether FHA primarily increases IgE–mediated, non–IgE–mediated FA, or both. And the trends in the contributions of FHA to food sensitization (FS) and FA remain unclear. We aim to clarify the associations among FHA, FS and FA and to understand the trends in the contributions of FHA to FS and FA.MethodsWe used chi–square test and mediating effect model to analyze the associations among FHA, FS and FA through comparisons between two cross–sectional investigations on FA in children under 2 years old in 2009 and 2019.ResultsIn 2009 and 2019, the positive FHA proportion tended to be increasing without significance (28.9% to 31.6%, P = 0.39). Subgroup analysis showed the FS rate in FA group decreased significantly (37/39 to 44/62, P = 0.003). In 2009, the FS rate and FA prevalence were higher in FHA (+) group than in FHA (–) group (26% vs. 14.7%, P = 0.008 and 15% vs. 7.7%, P = 0.03), and FS had a complete mediating effect on the association between FHA and FA (Z = 2.54, P = 0.011), but the results lost significance in 2019.ConclusionsThe association between FHA and FA was completely mediated by FS, which means FHA mainly increases IgE–mediated FA. And the contributions of FHA to FS and FA tended to be stabilized or even diminished, which means FHA alone could no longer be enough to screen high–risk children.

BackgroundAlthough epidemiological trends of childhood food sensitization (FS) in IgE-mediated food allergy were reported in China, few studies have examined at changes in its risk factors.ObjectiveTo investigate the change in early-life risk factors associated with childhood food sensitization during 2009–2019 in China.MethodsData from two cross-sectional surveys conducted in 2009 and 2019 (401 and 513 children, respectively) were analyzed. The results of skin prick tests and information on food sensitization-related risk factors in children were summarized, including family history of atopic disease (FHA), demographic characteristics, method of delivery, feeding patterns, sibship size, pet ownership, and vitamin D supplementation. Binary logistic regression was used to calculate the odds ratio and the regression coefficient β-value of risk factors in the 2009 and 2019 surveys separately. Then, coefficient β-value differences between the two surveys were analyzed by the bdiff command in STATA to describe the change in risk factors over 10 years.ResultsThe 2009 survey revealed that FHA, age, only child, and feeding patterns were associated with food sensitization. The 2019 survey showed that food sensitization was affected by age, sex, and feeding patterns. However, from 2009 to 2019, the probability of food sensitization in the only-child group significantly increased by 226.0% (β-value difference = 0.81, P = 0.024) and decreased by 65.0% in female children (β-value difference = −1.06, P = 0.008). The effect of age on food sensitization decreased by 50.0% (β-value difference = −0.69, P &lt; 0.001) over 10 years.ConclusionThe effect of FHA and common lifestyle factors on food sensitization did not significantly change during 2009−2019. However, the influence of demographic characteristics on food sensitization has changed since 2009; that is, older age, male gender, and only child are more likely to develop food sensitization, which needs to be considered in future epidemiological surveys.Clinical Trial Registrationhttp://www.chictr.org.cn/, identifier ChiCTR1900024338.