Jane Grundy

Prevalence and cumulative incidence of food hypersensitivity in the first 3 years of life

Background:  Prevalence and incidence of food hypersensitivity (FHS) and its trends in early childhood are unclear.

Time trends in the prevalence of peanut allergy: three cohorts of children from the same geographical location in the UK

Background:  This article investigated the prevalence of peanut allergy in three cohorts of children born in the same geographical location, Isle of Wight, UK and seeks to determine whether the prevalence of peanut allergy has changed between 1994 and 2004.

Prevalence of sensitization reported and objectively assessed food hypersensitivity amongst six‐year‐old children: A population‐based study

There is a paucity of information on food hypersensitivity (FHS) in young children and there are even fewer population‐based studies in this area. The aim of the study was to determine the prevalence of parentally reported FHS, and objectively diagnosed FHS amongst six‐year‐old children and to establish the rates of sensitization to key allergens. This population‐based cohort study recruited 798 6‐year‐olds resident on the Isle of Wight (UK). Sensitization rates, reported rates of FHS and objectively assessed FHS was established using food challenges. A total of 94 (11.8%) 6 yr olds reported a problem with a food or food ingredient. The rate of sensitization to the pre‐defined panel of food allergens was 25/700 (3.6%). Based on open food challenge and/or suggestive history and skin tests, the prevalence of FHS was 2.5% (95% CI 1.5–3.8). Based on double‐blind challenges, a clinical diagnosis or suggestive history and positive skin tests, the prevalence was 1.6% (95% CI 0.9–2.7). The rates of perception of FHS are higher than the prevalence of sensitization to main food allergens and the prevalence of FHS based on food challenges. Milk, peanut and wheat were the key food allergens amongst those with positive challenges.

Influence of atopy and asthma on exhaled nitric oxide in an unselected birth cohort study.

Background Asthma is considered to be associated with elevated levels of exhaled nitric oxide (FeNO). The nature of this relationship and how it is influenced by atopy are still not resolved. Methods The Isle of Wight birth cohort (N=1456) was reassessed at 18 years of age. Participants able to attend the research centre were assessed by questionnaires, skin prick testing and FeNO in order to explore the interrelationship between asthma, atopy and FeNO. Results Atopy was significantly associated with higher levels of FeNO. However, the level of FeNO for non-atopic asthmatic participants was no different to the non-atopic no-asthma group. The highest levels of FeNO were seen in subjects with both atopy and asthma. In addition, FeNO was positively associated with increasing atopic burden as evidenced by increasing FeNO with increasing skin prick testing positivity, and with increasing severity of atopic asthma as evidenced by the number of attacks of wheezing. FeNO and current inhaled corticosteroid use were not significantly associated. Conclusions FeNO behaves as a biomarker of atopy and the “allergic asthma” phenotype rather than asthma itself. This may explain why FeNO-guided asthma treatment outcomes have proved to be of limited success where atopic status has not been considered and accounted for.

Factors associated with maternal dietary intake, feeding and weaning practices, and the development of food hypersensitivity in the infant

Maternal diet during pregnancy and breastfeeding, as well as infant feeding and weaning practices, may play a role in the development of sensitization to food and food hypersensitivity (FHS) and need further investigation. Pregnant women were recruited at 12 wk pregnancy. Information regarding family history of allergy was obtained by means of a questionnaire. A food frequency questionnaire was completed at 36 wk gestation. Information regarding feeding practices and reported symptoms of atopy was obtained during the infants’ first 3 yr of life. Children were also skin‐prick tested at 1, 2 and 3 yr to a pre‐defined panel of food allergens. Food challenges were conducted where possible. Maternal dietary intake during pregnancy, and breast‐feeding duration did not influence the development of sensitization to food allergens or FHS, but weaning age (≥16 wk) did for sensitization at 1 yr (p = 0.03), FHS by 1 yr (p = 0.02), sensitization at 3 yr (p = 0.01) and FHS by 3 yr (p = 0.02). In contrast, children who were not exposed to a certain food allergen before the age of 3–6 months were less likely to become sensitized or develop FHS. Women with a family history of allergic disease were more likely to breastfeed exclusively at 3 months (p = 0.008) and avoid peanuts from the infant’s diet at 6 months (p = 0.03). Maternal dietary intake during pregnancy, and breast‐feeding duration did not appear to influence the development of sensitization to food allergens or FHS. Weaning age may affect sensitization to foods and development of FHS. A history of allergic disease has very little impact on maternal dietary, feeding, and weaning practices.

Changing prevalence of wheeze, rhinitis and allergic sensitisation in late childhood: findings from 2 Isle of Wight birth cohorts 12 years apart

While the prevalence of asthma in children is decreasing or remaining the same, time trends in the prevalence of rhinitis in children are not known. Understanding sensitisation trends may help inform about trends in asthma and rhinitis prevalence.

Health-related quality of life in children with perceived and diagnosed food hypersensitivity

The few studies measuring health‐related quality of life (HRQL) in food hypersensitivity (FHS) have found significantly reduced HRQL in patients and their families, particularly in the areas of family and social activities, emotional issues and family economy. One aspect that has not been studied is the effect of suspected FHS (food allergy/intolerance) vs. diagnosed FHS [based on a food challenge or a positive skin prick test (SPT) and good clinical history] on HRQL. Therefore, the aim of this study was to investigate the HRQL in children with a proven diagnosis of FHS vs. those with reported FHS.

Are exhaled nitric oxide measurements using the portable NIOX MINO repeatable

BackgroundExhaled nitric oxide is a non-invasive marker of airway inflammation and a portable analyser, the NIOX MINO (Aerocrine AB, Solna, Sweden), is now available. This study aimed to assess the reproducibility of the NIOX MINO measurements across age, sex and lung function for both absolute and categorical exhaled nitric oxide values in two distinct groups of children and teenagers.MethodsPaired exhaled nitric oxide readings were obtained from 494 teenagers, aged 16-18 years, enrolled in an unselected birth cohort and 65 young people, aged 6-17 years, with asthma enrolled in an interventional asthma management study.ResultsThe birth cohort participants showed a high degree of variability between first and second exhaled nitric oxide readings (mean intra-participant difference 1.37 ppb, 95% limits of agreement -7.61 to 10.34 ppb), although there was very close agreement when values were categorised as low, normal, intermediate or high (kappa = 0.907, p < 0.001). Similar findings were seen in subgroup analyses by sex, lung function and asthma status. Similar findings were seen in the interventional study participants.ConclusionsThe reproducibility of exhaled nitric oxide is poor for absolute values but acceptable when values are categorised as low, normal, intermediate or high in children and teenagers. One measurement is therefore sufficient when using categorical exhaled nitric oxide values to direct asthma management but a mean of at least two measurements is required for absolute values.

The prevalence, natural history and time trends of peanut allergy over the first 10 years of life in two cohorts born in the same geographical location 12 years apart

The aim of this study was to explore the natural history of peanut allergy in childhood in two birth cohorts from the same geographical region in the South of England.

What does adolescent undiagnosed-wheeze represent? Findings from the Isle of Wight Cohort

We sought to characterise adolescent wheeze in the absence of asthma, which we termed “undiagnosed wheeze”. The Isle of Wight Birth Cohort (n=1,456) was reviewed at 1, 2, 4, 10 and 18 yrs. Using questionnaire responses, “asthma” was defined as “ever had asthma” plus either “wheezing in the last 12 months” or “taking asthma treatment in the last 12 months”; “undiagnosed wheeze” as “wheeze in the last 12 months” but “no” to “ever had asthma”; and remaining subjects termed “non-wheezers”. Undiagnosed wheeze (prevalence 4.9%) accounted for 22% of wheezing at 18 yrs. This was largely adolescent-onset with similar symptom frequency and severity to diagnosed asthma. However, undiagnosed wheezers had significantly higher forced expiratory volume in 1 s to forced vital capacity ratio, less bronchodilator reversibility and bronchial hyperresponsiveness, and were less frequently atopic than asthmatics. Undiagnosed wheezers had earlier smoking onset, higher smoking rates and monthly paracetamol use than non-wheezers. Logistic regression identified paracetamol use (OR 1.11, 95% CI 1.01–1.23; p=0.03), smoking at 18 yrs (OR 2.54, 95% CI 1.19–5.41; p=0.02), rhinitis at 18 yrs (OR 2.82, 95% CI 1.38–5.73; p=0.004) and asthmatic family history (OR 2.26, 95% CI 1.10–4.63; p=0.03) as significant independent risk factors for undiagnosed wheeze. Undiagnosed wheeze is relatively common during adolescence, differs from diagnosed asthma and has strong associations with smoking and paracetamol use. Better recognition of undiagnosed wheeze and assessment of potential relevance to adult health is warranted.