Food Allergy: A Comprehensive Population-Based Cohort Study.

OBJECTIVE: To determine the incidence and temporal trends of food allergies. PATIENTS AND METHODS: We performed a historical cohort study to describe the epidemiology of food allergies among residents of all ages in Olmsted County, Minnesota, during a 10-year period from January 2, 2002, through December 31, 2011, using the Rochester Epidemiology Project database. Overall incidence and trends in biannual incidence rates over time were evaluated. RESULTS: During the 10-year study period, 578 new cases of food allergies were diagnosed. The average annual incidence rate was significantly higher among males compared with females (4.1 [95% CI, 3.6-4.5] vs 3.0 [95% CI, 2.7-3.4]; P<.001; per 10,000 person-years; 3.6 per 10,000 person-years overall). The pediatric incidence rate of food allergy increased from 7.0 (95% CI, 6.2-8.9) to 13.3 (95% CI, 10.9-15.7) per 10,000 person-years between the 2002-2003 and 2006-2007 calendar periods and then stabilized at 12.5 and 12.1 per 10,000 person-years in the last 2 calendar periods. Milk, peanut, and seafood were the most common allergen in infancy, in children between ages 1 and 4 years, and in the adult population, respectively. CONCLUSION: This is one of the first population-based studies to examine the temporal trends of food allergies. The incidence of food allergies increased markedly between 2002 and 2009, with stabilization afterward. Additional longitudinal studies are warranted to assess for epidemiological evidence of changes in food allergy incidence with changing recommendations for allergenic food introduction.

Vitamin D and food allergies in children: A systematic review and meta-analysis.

BACKGROUND: Vitamin D insufficiency has been associated with immune dysfunction and linked to the epidemic of atopic diseases in the Western hemisphere, yet there are studies with conflicting results, and the risk has not been quantified uniformly across studies. OBJECTIVE: To perform a systematic review and meta-analysis to evaluate and quantify if vitamin D deficiency is associated with the presence and persistence of food allergy. METHODS: A systematic review was undertaken to assess for the association between food allergy and vitamin D status in children. RESULTS: A total of 368 citations relevant to this systematic review were identified. In the whole review, 5105 children were included. We did not find a significant association between 25 hydroxy vitamin D (25(OH)D) status and risk of food allergy in children (odds ratio [OR] 1.35 [95% confidence interval {CI}, 0.79-2.29]; p = 0.27, I2 = 58.3%). We conducted subgroup analyses based on different cutoffs of the 25(OH)D status (20 versus 30 ng/mL). Only one study used 30 ng/mL and found that children with <30 ng/mL were more likely to report food allergy than children with a 25(OH)D status of ≥30 ng/mL (OR 2.04 [95% CI, 1.02-4.04]; p = 0.04). Four studies compared children with a 25(OH)D status of <20 ng/mL to children with a 25(OH)D status of ≥20 ng/mL and found no significant differences (OR 1.18 [95% CI, 0.62-2.27]; p = 0.62, I2 = 62.7%). CONCLUSION: Based on the studies analyzed, this systematic review did not identify a significant association between vitamin D status and food allergy. Interpretation of the included studies was limited by a lack of a standard definition for vitamin D deficiency and insufficient knowledge regarding the optimal vitamin D status needed to impact immune function. Longitudinal studies are warranted to assess if vitamin D might contribute to the development of food allergy.