Food Allergy Prevalence in Two Population-Based UK Cohorts Born 12 Years Apart.

Background: Adverse food reactions include food allergy (FA; immune-mediated) and food intolerances (non-immune-mediated). FA are classified into IgE- and non-IgE-mediated FA. There is limited information available about changes in FA prevalence over time.

Methods: Two cohorts of children were evaluated, born on the Isle of Wight (IOW) 12 years apart, the IOW birth cohort (IOWBC; 1989-1990) and the FA and Intolerance Research birth cohort (FAIRBC; 2001-2002). We compared the prevalence of parental reported reactions to foods (adverse food reactions), allergic sensitisation to foods and FA between the IOWBC and FAIRBC, at ages 1, 2, 3-4 and 10 years. FA included both IgE- and non-IgE-mediated FA.

Results: Reported adverse reactions to food and sensitisation rates remained stable between the two cohorts. For example, FA at age 3-4 years was reported in 9.1% (95% CI: 7.5, 10.7) in IOWBC and 8.3% (95% CI: 6.5, 10.1) in FAIRBC (p = 0.57) and food sensitisation by skin prick test at age 3-4 years was found in 3.2% (95% CI: 2.1, 4.3) in IOWBC and 4.5% (95% CI: 2.9, 6.1) in FAIRBC (p = 0.20). Confirmed FA prevalence was lower in FAIRBC than IOWBC at ages 1, 2 and 3-4, but these differences were not significant after adjustment for multiple comparisons. For example, FA at age 3-4 years was confirmed in 5.0% (95% CI: 3.8, 6.2) in IOWBC and 3.0% (95% CI: 1.9, 4.2) in FAIRBC (p = 0.03, significance threshold after Bonferroni correction p < 0.004). Confirmed cow's milk allergy rate was higher in IOWBC than FAIRBC at 3 years (< 0.001) but not at other time points.

Conclusion: Our data show no evidence of changes in rates of adverse reactions to foods, food sensitisation or food allergy during the first 10 years of life between two cohorts born in England in 1989-1990 and 2001-2002.