Frequency of food allergy in Europe:an updated systematic review and meta-analysis

Food allergy (FA) is increasingly reported in Europe, however, the latest prevalence estimates were based on studies published a decade ago. The present work provides the most updated estimates of the prevalence and trends of FA in Europe. Databases were searched for studies published between 2012 and 2021, added to studies published up to 2012. In total, 110 studies were included in this update. Most studies were graded as moderate risk of bias. Pooled lifetime and point prevalence of self-reported FA were 19.9% (95% CI 16.6–23.3) and 13.1% (95% CI 11.3–14.8), respectively. The point prevalence of sensitization based on specific IgE (slgE) was 16.6% (95% CI 12.3–20.8), skin prick test (SPT) 5.7% (95% CI 3.9–7.4), and positive food challenge 0.8% (95% CI 0.5–0.9). While lifetime prevalence of self-reported FA and food challenge positivity only slightly changed, the point prevalence of self-reported FA, sIgE and SPT positivity increased from previous estimates. This may reflect a real increase, increased awareness, increased number of foods assessed, or increased number of studies from countries with less data in the first review. Future studies require rigorous designs and implementation of standardized methodology in diagnosing FA, including use of double-blinded placebo-controlled food challenge to minimize potential biases

Prevalence estimates of eight big food allergies in Europe: Updated systematic review and meta-analysis

In 2014, the European Academy of Allergy and Clinical Immunology published prevalence estimates for food allergy (FA) and food sensitization (FS) to the so-called eight big food allergens (i.e. cow's milk, egg, wheat, soy, peanut, tree nuts, fish and shellfish) in Europe for studies published between 2000 and 2012. The current work provides 10-year updated prevalence estimates for these food allergens. A protocol was registered on PROSPERO before starting the research (reference number CRD42021266657). Six databases were searched for studies published 2012–2021, added to studies published up to 2012, resulting in a total of 93 studies. Most studies were graded as at moderate risk of bias. The overall pooled estimates for all age groups of self-reported lifetime prevalence were as follows: cow's milk (5.7%, 95% confidence interval 4.4–6.9), egg (2.4%, 1.8–3.0), wheat (1.6%, 0.9–2.3), soy (0.5%, 0.3–0.7), peanut (1.5%, 1.0–2.1), tree nuts (0.9%, 0.6–1.2), fish (1.4%, 0.8–2.0) and shellfish (0.4%, 0.3–0.6). The point prevalence of food challenge-verified allergy were as follows: cow's milk (0.3%, 0.1–0.5), egg (0.8%, 0.5–1.2), wheat (0.1%, 0.01–0.2), soy (0.3%, 0.1–0.4), peanut (0.1%, 0.0–0.2), tree nuts (0.04%, 0.02–0.1), fish (0.02%, 0.0–0.1) and shellfish (0.1%, 0.0–0.2). With some exceptions, the prevalence of allergy to common foods did not substantially change during the last decade; variations by European regions were observed

Sibship size, birth order and risk of asthma and allergy: protocol for a systematic review and meta-analysis

Introduction The hygiene hypothesis suggests that reduced exposure to microbes might have contributed to the increase in prevalence and incidence of asthma and allergy observed during the second half of the last century. Following this proposal, several studies have investigated the role of sibship size and birth order in the development of asthma and allergic diseases, but the underlying evidence is conflicting. The objective of the present systematic review will be to identify, critically appraise and synthesise previous primary studies investigating the association of sibship size and birth order with the risk of asthma and allergic diseases. Methods and analysis The following databases will be searched: AMED, CABI, CINAHL, Embase, Google Scholar, OAIster, Open Access Theses and Dissertations, Open Grey, ProQuest Dissertations & Theses Global, PsycINFO, PubMed, SciELO, Scopus, Web of Science and WHO Global Index Medicus. Studies published up until 31 December 2020 will be eligible. There will be no restrictions by language and geographical location. Risk of bias in the included studies will be assessed using the Effective Public Health Practice Project quality assessment tool. The produced evidence will be synthesised narratively, and studies that present comparable numerical data will be included in meta-analyses using random effects model. Ethics and dissemination Only data from the published literature will be included in this systematic review. Therefore, no ethical approval is required. The final review paper will be published in a peer-reviewed journal. PROSPERO registration number CRD42020207905

Comparison of clinician diagnosis of COVID-19 with real time polymerase chain reaction in an adult-representative population in Sweden

Abstract Background Due to the high transmissibility of SARS-CoV-2, accurate diagnosis is essential for effective infection control, but the gold standard, real-time reverse transcriptase-polymerase chain reaction (RT-PCR), is costly, slow, and test capacity has at times been insufficient. We compared the accuracy of clinician diagnosis of COVID-19 against RT-PCR in a general adult population. Methods COVID-19 diagnosis data by 30th September 2021 for participants in an ongoing population-based cohort study of adults in Western Sweden were retrieved from registers, based on positive RT-PCR and clinician diagnosis using recommended ICD-10 codes. We calculated accuracy measures of clinician diagnosis using RT-PCR as reference for all subjects and stratified by age, gender, BMI, and comorbidity collected pre-COVID-19. Results Of 42,621 subjects, 3,936 (9.2%) and 5705 (13.4%) had had COVID-19 identified by RT-PCR and clinician diagnosis, respectively. Sensitivity and specificity of clinician diagnosis against RT-PCR were 78% (95%CI 77–80%) and 93% (95%CI 93–93%), respectively. Positive predictive value (PPV) was 54% (95%CI 53–55%), while negative predictive value (NPV) was 98% (95%CI 98–98%) and Youden’s index 71% (95%CI 70–72%). These estimates were similar between men and women, across age groups, BMI categories, and between patients with and without asthma. However, while specificity, NPV, and Youden’s index were similar between patients with and without chronic obstructive pulmonary disease (COPD), sensitivity was slightly higher in patients with (84% [95%CI 74–90%]) than those without (78% [95%CI 77–79%]) COPD. Conclusions The accuracy of clinician diagnosis for COVID-19 is adequate, regardless of gender, age, BMI, and asthma, and thus can be used for screening purposes to supplement RT-PCR

Birth order, sibship size, and risk of atopic dermatitis, food allergy, and atopy: A systematic review and meta‐analysis

Abstract Background Atopic dermatitis and food allergy are two frequently concomitant manifestations of the presence of atopy. A substantial number of studies have been published on the association of birth order and sibship size (number of siblings) with atopic dermatitis, food allergy, and atopy. The present work is the first systematic synthesis of the existing literature on this topic. Methods Fifteen databases were searched. Screening, data extraction, and quality assessment were performed by independent pairs. Comparable numerical data were statistically synthesized using random‐effects robust variance estimation. Results In total, 114 studies were included out of 8819 papers obtained from database searches. Birth order ≥2 versus 1 was associated with lower risk of ever atopic dermatitis (pooled risk ratio [RR] 0.91, 95% CI 0.84–0.98), current food allergy (RR 0.77, 95% CI 0.66–0.90), and positive skin prick test (SPT) to common aeroallergens (RR 0.86, 95% CI 0.77–0.97). Sibship size ≥2 versus 1 was associated with decreased risk of current atopic dermatitis (RR 0.90, 95% CI 0.83–0.98), ever atopic dermatitis (RR 0.92, 95% CI 0.86–0.97), and positive SPT to common aeroallergens (RR 0.88, 95% CI 0.83–0.92). No putative associations were seen regarding atopy assessed through allergen‐specific immunoglobulin E with common allergens. Conclusion The presence of siblings and being second‐born or later may decrease the lifetime risk of atopic dermatitis and food allergy, albeit marginally. Similar association was seen with SPT sensitization. However, significant protection was not found for IgE sensitization

Siblings and risk of allergic rhinitis : A systematic review and meta-analysis

Following the “hygiene hypothesis” and the increase in the prevalence of atopic diseases such as allergic rhinitis, a plethora of studies have investigated the role of sibship composition as a protective factor, but findings are conflicting. The aim of this study was to synthesize the global literature linking birth order and sibship size (number of siblings) to the risk of allergic rhinitis. Fifteen databases were systematically searched, with no restrictions on publication date or language. Observational studies with defined sibship composition (birth order or sibship size) as exposure and allergic rhinitis or allergic rhinoconjunctivitis (self-reported or clinically diagnosed) as outcome were eligible. Study selection, data extraction, and quality assessment were performed independently in pairs. Relevant data were summarized in tables. Comparable numerical data were analyzed using meta-analysis with robust variance estimation (RVE). Seventy-six reports with >2 million subjects were identified. Being second- or later-born child was associated with protection against both current (pooled risk ratio [RR] 0.79, 95% CI 0.73–0.86) and ever (RR 0.77, 95% CI 0.68–0.88) allergic rhinitis. Having siblings, regardless of birth order, was associated with a decreased risk of current allergic rhinitis (RR 0.89, 95% CI 0.83–0.95) and allergic rhinoconjunctivitis (RR 0.92, 95% CI 0.86–0.98). These effects were unchanged across age, time period, and geographical regions. Our findings thus indicate that primarily, a higher birth order, and to a lesser extent the number of siblings, is associated with a lower risk of developing allergic rhinitis.publishedVersionPeer reviewe