Population response to change in infant feeding guidelines for allergy prevention

Trends of Peanut-Induced Anaphylaxis Rates Before and After the 2017 Early Peanut Introduction Guidelines in Montreal, Canada

BACKGROUND

Food allergies, particularly peanut, represent the predominant cause of anaphylaxis. Whereas early allergen introduction has emerged as a potential preventive strategy, the precise impact of recent guidelines on peanut-induced anaphylaxis rates in Canada remains unclear.

OBJECTIVE

To assess the impact of the 2017 Addendum Guidelines for the Prevention of Peanut Allergy on peanut-induced anaphylaxis rates in Canada.

METHODS

Using a comprehensive longitudinal registry capturing pediatric anaphylaxis presentations to the Montreal's Children's Hospital, we compared children with and without known peanut allergy who presented with peanut-induced anaphylaxis between 2011 and 2019 inclusive, excluding data beyond 2019 owing to the Coronavirus disease 2019 (COVID-19) pandemic. We calculated rates of peanut-induced anaphylaxis presentations per 100,000 age-adjusted all-cause emergency department visits using 4-month intervals. Interrupted time series analysis was used to compare anaphylaxis rate trends before and after 2017 for children ages 0 to 2 and 3 to 17 years.

RESULTS

We examined 2,011 cases of pediatric anaphylaxis, including 429 (21%) triggered by peanuts. Compared with pre-guideline estimates, the yearly rate of change of peanut anaphylaxis rates decreased by 7.96 (95% confidence interval -14.57 to -1.36; P = .018) after 2017 among patients with new-onset anaphylaxis in children 2 years of age or younger (n = 109). No significant changes were identified for older patients ages 3 to 17, or in patients with known peanut allergy.

CONCLUSIONS

Early introduction guidelines in Canada are associated with a reduced risk of new-onset peanut-induced anaphylaxis in young children within a single center in Montreal. Further research is required to assess the impact on a wider population and other food allergens.

Revised Swedish infant feeding guidelines are associated with earlier introduction of allergenic foods

BACKGROUND

Randomized controlled trials have demonstrated that early introduction of allergenic foods, such as peanut and egg, can reduce food allergy in high-risk children. Many international guidelines recommend introduction of allergenic foods in the first year of life, and accordingly, the Swedish National Food agency released updated guidelines in June 2019.

OBJECTIVE

Our aim was to examine whether the age at introduction and consumption frequency of allergenic foods have changed since release of the revised national guidelines on the introduction of solid foods in Sweden.

METHODS

Children born between June 2016 and December 2018 (n = 1925) were compared with children born between June 2019 and April 2021 (n = 1761) by using data from the NorthPop Birth Cohort study. Data on food introduction, eczema, and food allergy were prospectively collected until age 18 months by using web-based questionnaires. IgE sensitization was assessed at 18 age months.

RESULTS

The proportion of participants who had been introduced to egg, legume, soy products, peanut, almond, and cashew nut during the first year of life increased after implementation of the revised national guidelines. The most significant changes were seen for legume (from 55.2% to 69.8% [adjusted odds ratio = 1.90 (95% CI = 1.62-2.24)]) and peanut (from 29.2% to 43.2% adjusted odds ratio = 1.87 (95% CI = 1.55-2.24)]); consumption frequency had also increased. No differences in the prevalence of eczema, food allergy, or sensitization to the foods of interest were found.

CONCLUSION

Since release of the revised guidelines, infants in the general population are introduced to and consume a variety of allergenic foods earlier and more frequently; however, early manifestations of allergic disease have remained unchanged.

Rural parents' adherence to infant feeding guidelines to prevent allergy: a cross sectional study in New South Wales

BACKGROUND

Responding to international research showing that early introduction of common food allergens can reduce the chance of developing allergies, in 2016 the Australasian Society of Clinical Immunology and Allergy (ASCIA) revised allergen introduction guidelines, recommending earlier introduction of allergens to infants in their first year. Australia has high food allergy rates, and limited understanding of adherence to allergen introduction guidelines, especially in rural areas. This project explored rural parent adherence to ASCIA guidelines.

METHODS

This was a mixed method cross sectional study using an online survey including multiple-choice and qualitative short answer responses. The sample were 336 women from two rural health districts in New South Wales. All were aged 18 or over, and either pregnant or had delivered a baby since July 2018. Descriptive statistics were used to measure behavioural alignment with the recommended guidelines, thematic analysis was used to analyse attitudes and explanations.

RESULTS

In 84.3% of children, feeding adhered to all four guidelines studied, including no elimination of allergens during pregnancy (98%), age of introduction of solids (97.7%), continuation of breast milk/cow's milk formula during introduction of solids (95%), and age of introduction of allergens (92.9%). Adherence was not significantly correlated with the education (X2 = 17.9, P = .056), prior history of allergy [neither mother (X2 = 0.945,P = .623) nor previous children (X2 = 0.401,P = .818)], or primary care received during pregnancy. More than 90% of participants agreed or strongly agreed that the guidelines are realistic, trustworthy, and important for the health of their child. However, thematic analysis revealed that parents' perceptions of a child's individual progress, and medical conditions or other circumstances, such as challenges with breastfeeding, will often take precedence over adherence to specific guideline recommendations.

CONCLUSIONS

High rates of adherence with ASCIA guidelines found here are comparable with findings from metropolitan studies and encouraging for future population health. Participant comments on the guidelines imply to rural policymakers that there are multiple influences on parent decisions about infant feeding, often including parents' own intuition and experiences. Further studies to improve understanding of the role of information, carers, and other influences on parent decision-making concerning feeding attitudes and behaviours will be necessary to optimise adherence in rural areas.

Increasing emergency department visits for anaphylaxis in very early childhood: A canary in the coal mine

AIM

The incidence of anaphylaxis is increasing globally in tandem with changing environmental and lifestyle factors. There is very limited data on very early childhood presentations. We aim to assess changes in rates, characteristics and management of infant anaphylaxis in a paediatric ED over a 15-year period.

METHODS

We conducted a retrospective study of children <2 years of age who presented with verified anaphylaxis comparing cases in years 2003-2007 with those in 2013-2017. Standardised information was collected on demographics, clinical presentation, management and triggers.

RESULTS

Manually confirmed anaphylaxis rates in <2 year olds increased from 3.6 to 6.2 per 104 population (OR 1.7, 95% CI: 1.3-2.7; p < 0.001) with the greatest increase in <1 year olds. Anaphylaxis severity increased between 2003-2007 and 2013-2017 (OR 2.3, 95% CI: 1.2-4.3; p = 0.018). Failure to administer adrenaline was reduced in 2013-2017 (p = 0.007). Food was the leading anaphylaxis trigger (97.85%).

CONCLUSION

This is the first study to suggest an increase in the incidence and severity of ED anaphylaxis presentations in children aged <2 years. Increased awareness of specific characteristics in this age group is required to facilitate timely recognition and optimal management. Further large-scale studies are warranted to understand underlying environmental drivers and find prevention strategies to reduce the burden of disease.

Impact of public health interventions for food allergy prevention on rates of infant anaphylaxis

BACKGROUND

Eleven percent of Australian infants have confirmed food allergy. We hypothesized earlier introduction may lead to higher rates of infant anaphylaxis, irrespective of whether the overall rate of food allergy in the population was ultimately reduced.

OBJECTIVE

To determine whether a public health campaign, targeting earlier introduction of allergenic foods, affected rates of infant anaphylaxis.

METHODS

Data were obtained from St John Ambulance (SJA) Western Australia and Western Australian emergency departments (ED) on infant (≤12 months) anaphylaxis over a 5-year period (July 1, 2015 to June 30, 2020). Adrenaline administration data were collected in the SJA dataset. Poisson regression was undertaken to assess trends in anaphylaxis over time. Segmented regression analysis was undertaken to assess differences in anaphylaxis rates before and after intervention.

RESULTS

The SJA and ED datasets included 172 and 294 events, respectively, coded as infant anaphylaxis. Rates of infant anaphylaxis increased over time for both SJA and ED datasets, with a 1-year increase rate ratio of 1.21 (95% confidence interval, 1.09-1.35; P value < .01) and 1.11 (95% confidence interval, 1.02-1.20; P = .01), respectively. Segmented regression indicated no significant difference in rates after intervention. Adrenaline was not coded as being administered in 109 of the 172 anaphylaxis events.

CONCLUSION

Rates of infant anaphylaxis increased over the 5-year reporting period; however, there was no clear increase related to the timing of the public health campaign implementation. Reported adrenaline use was suboptimal. Assessing rates of food allergy in all age groups is required to determine whether there has been an overall reduction in food allergy owing to the intervention.

Association Between Earlier Introduction of Peanut and Prevalence of Peanut Allergy in Infants in Australia

IMPORTANCE

Randomized clinical trials showed that earlier peanut introduction can prevent peanut allergy in select high-risk populations. This led to changes in infant feeding guidelines in 2016 to recommend early peanut introduction for all infants to reduce the risk of peanut allergy.

OBJECTIVE

To measure the change in population prevalence of peanut allergy in infants after the introduction of these new guidelines and evaluate the association between early peanut introduction and peanut allergy.

DESIGN

Two population-based cross-sectional samples of infants aged 12 months were recruited 10 years apart using the same sampling frame and methods to allow comparison of changes over time. Infants were recruited from immunization centers around Melbourne, Australia. Infants attending their 12-month immunization visit were eligible to participate (eligible age range, 11-15 months), regardless of history of peanut exposure or allergy history.

EXPOSURES

Questionnaires collected data on demographics, food allergy risk factors, peanut introduction, and reactions.

MAIN OUTCOME AND MEASURES

All infants underwent skin prick tests to peanut and those with positive results underwent oral food challenges. Prevalence estimates were standardized to account for changes in population demographics over time.

RESULTS

This study included 7209 infants (1933 in 2018-2019 and 5276 in 2007-2011). Of the participants in the older vs more recent cohort, 51.8% vs 50.8% were male; median (IQR) ages were 12.5 (12.2-13.0) months vs 12.4 (12.2-12.9) months. There was an increase in infants of East Asian ancestry over time (16.5% in 2018-2019 vs 10.5% in 2007-2011), which is a food allergy risk factor. After standardizing for infant ancestry and other demographics changes, peanut allergy prevalence was 2.6% (95% CI, 1.8%-3.4%) in 2018-2019, compared with 3.1% in 2007-2011 (difference, -0.5% [95% CI, -1.4% to 0.4%]; P = .26). Earlier age of peanut introduction was significantly associated with a lower risk of peanut allergy among infants of Australian ancestry in 2018-2019 (age 12 months compared with age 6 months or younger: adjusted odds ratio, 0.08 [05% CI, 0.02-0.36]; age 12 months compared with 7 to less than 10 months: adjusted odds ratio, 0.09 [95% CI, 0.02-0.53]), but not significant among infants of East Asian ancestry (P for interaction = .002).

CONCLUSIONS AND RELEVANCE

In cross-sectional analyses, introduction of a guideline recommending early peanut introduction in Australia was not associated with a statistically significant lower or higher prevalence of peanut allergy across the population.

Real-World LEAP Implementation

Purpose of Review

In 2015, findings from the Learning Early About Peanut allergy (LEAP) trial provided the first convincing evidence that peanut allergy may be preventable through early peanut introduction into the infant diet. Here we discuss implementation of the LEAP study findings around the world and emerging evidence of the impacts on infant feeding and food allergy.

Recent Findings

The LEAP findings led to rapid changes in allergy prevention guidelines internationally to recommend early peanut introduction. There is now emerging evidence that this has been followed by a substantial increase in early peanut introduction to infants. Studies investigating the impact of these changes in infant feeding practices on the prevalence of peanut allergy are underway.

Summary

The LEAP trial represented a significant step forwards in food allergy prevention and new research over the past 5 years has provided insights into how best to implement this intervention in the real world.

The Australian Feeding Infants and Toddler Study (OzFITS 2021): Breastfeeding and Early Feeding Practices

The Australian Feeding Infants and Toddler Study 2021 (OzFITS 2021) is a nationwide survey of Australian caregivers' infant and toddler feeding practices. Here, we describe breastfeeding rates and duration, use of breastmilk substitutes, and introduction of complementary (solid) foods, including common food allergens. Caregivers (n = 1140) were recruited by a digital marketing company and were interviewed using a structured telephone questionnaire to obtain information. Breastfeeding was initiated in 98% of infants, but the duration of exclusive breastfeeding to six months was less than 1%. Nearly 40% of children continued to receive breastmilk beyond one year, with 10% of toddlers receiving breastmilk at two years. One-quarter of infants were introduced to solid foods between 4 to 5 months, and nearly all infants had received solid foods by 7 months. New guidelines encourage the early introduction of potential food allergens to reduce the risk of allergy, and by 12 months, over 90% of children had been given eggs and peanuts. One-third of children received no breastmilk substitutes during their first year. One-third of infants first received breastmilk substitutes following birth and before discharge from the hospital. Of these infants, 30% ceased breastmilk substitute use after discharge. Our findings suggest a high rate of continued breastfeeding with 44% receiving breastmilk beyond 1 year. One approach to increase the duration of exclusive breastfeeding is to reduce breastmilk substitute use while in hospital.

International Peanut Allergy Prevention, 6 Years After the Learning Early About Peanut Study

Six years ago, the Learning Early About Peanut (LEAP) trial findings helped fundamentally shift the paradigm of peanut allergy prevention. Although the results of LEAP are well accepted, policy-makers, caregivers, and clinicians struggle with how best to implement and apply the study's key findings in clinical practice. Differences in guidelines highlight issues related to peanut allergy prevention implementation, including caregiver acceptability, cost, fidelity, feasibility, appropriateness, and adoption. The goals of this rostrum are to review how the LEAP study has informed international peanut allergy prevention policy, as well as to review the strengths and ongoing controversies in peanut allergy prevention implementation.

Increased Rates of Peanut and Tree Nut Aspiration as a Possible Consequence of Allergy Prevention by Early Introduction

BACKGROUND

Pediatric airway foreign bodies (FBs) are a surgical emergency, and peanuts and tree nuts (PN/TNs) can pose a significant aspiration risk in young children. In 2015, the Learning Early About Peanut allergy (LEAP) trial established that early introduction of peanuts in high-risk infants reduced the risk of developing a peanut allergy. Infant feeding guidelines were subsequently modified to actively encourage the introduction of allergenic foods for all infants. The impact of this shift in feeding advice on the incidence of PN/TN inhalation has not been previously studied.

OBJECTIVE

To determine the incidence of PN/TN inhalation presentations to a quaternary pediatric hospital between 2008 and 2018.

METHODS

A retrospective cohort study of children who were diagnosed with an airway FB by rigid bronchoscopy.

RESULTS

There were 200 cases of FB inhalation (35% PN/TN, 34% other foods, and 31% inorganic material). There was a rise in the total incidence of FB inhalation over the study period (incidence ratio rate [IRR], 1.09; P < .001). The rise was due to PN/TN (IRR, 1.16; P < .002) and other food inhalation (IRR, 1.12; P = .01), with no significant increase in inorganic FB aspiration (IRR, 1; P = .94). Between pre-LEAP (2008-2014) and post-LEAP (2015-2018) periods, there was a trebling, doubling, and no increase in the rate of PN/TN, other food, and inorganic FB inhalation, respectively.

CONCLUSIONS

Since the publication of the LEAP study, there has been a rise in PN/TN and other hard solid food inhalation at our institution. This study highlights the urgent need to engage the public to promote safe introduction of hard foods in young children.

Age and eczema severity, but not family history, are major risk factors for peanut allergy in infancy

BACKGROUND

Whether to screen high-risk groups before early peanut introduction is controversial.

OBJECTIVE

We sought to determine the risk of peanut allergy (PA) before peanut introduction for infants with (1) moderate-severe eczema, (2) another food allergy (FA), and/or (3) a first-degree relative with peanut allergy (FH).

METHODS

Infants aged 4 to 11 months with no history of peanut ingestion, testing, or reaction and at least 1 of the above risk factors received peanut skin prick test and, depending on skin prick test wheal size, oral food challenge or observed feeding.

RESULTS

A total of 321 subjects completed the enrollment visit (median age, 7.2 months; 58% males); 78 had eczema only, 11 FA only, 107 FH only, and 125 had multiple risk factors. Overall, 18% of 195 with eczema, 19% of 59 with FA, and 4% of 201 with FH had PA. Only 1% of 115 with FH and no eczema had PA. Among those with eczema, older age (odds ratio [OR], 1.3; 95% CI, 1.04-1.68 per month), higher SCORing Atopic Dermatitis score (OR, 1.19; 95% CI, 1.06-1.34 per 5 points), black (OR, 5.79; 95% CI, 1.92-17.4 compared with white), or Asian race (OR, 6.98; 95% CI, 1.92-25.44) and suspected or diagnosed other FA (OR, 3.98; 95% CI, 1.62-9.80) were associated with PA.

CONCLUSIONS

PA is common in infants with moderate-severe eczema, whereas FH without eczema is not a major risk factor, suggesting screening only in those with significant eczema. Even within the first year of life, introduction at later ages is associated with a higher risk of PA among those with eczema, supporting introduction of peanut as early as possible.

SmartStartAllergy: a novel tool for monitoring food allergen introduction in infants

Objectives

To estimate the proportion of infants introduced to peanut and other common food allergens by 12 months of age; to collect information about parent‐reported reactions to food.

Design, setting

Observational cohort study, applying the SmartStartAllergy SMS protocol and online questionnaire to parents of 12‐month‐old infants attending 69 Australian general practices between 21 September 2018 and 3 May 2019.

Participants

3374 parents recruited via the 69 participating general practices.

Main outcome measures

Proportions of infants who had eaten peanut and other common food allergens; proportions with parent‐reported reactions to food.

Results

1940 of 3374 invited parents participated in the study (response rate, 57%), of whom 836 (46%) completed the online questionnaire. At 12 months of age, 1673 of 1940 infants had eaten peanut‐including foods (86.2%; 95% confidence interval [CI], 84.6–87.7%); 235 of 1831 parents (12.8%; 95% CI, 11.3–14.5%) reported food‐related reactions. Questionnaire responses indicated that dairy was the food type most frequently reported to cause a food‐related reaction (72 of 835 exposed infants, 8.6%; 95% CI, 6.8–11%); peanut‐related reactions were reported for 20 of 764 exposed children (2.6%; 95% CI, 1.6–4.0%). 97 of 250 parent‐reported reactions to food (39%) did not include symptoms that suggested an IgE‐mediated allergic reaction.

Conclusion

Infant feeding practices in Australia have changed over the past decade; a large majority of infants are now fed peanut before 12 months of age. The SmartStartAllergy program allows monitoring of infant feeding practices in primary care, as well as of parent‐reported reactions to food in infants.

Factors influencing adherence in a trial of early introduction of allergenic food

BACKGROUND

The Enquiring About Tolerance (EAT) study examined whether the early introduction of 6 allergenic foods from 3 months of age in exclusively breastfed infants prevented the development of food allergy. The intervention was effective in the per-protocol analysis for allergy to 1 or more foods and for egg and peanut individually, but only 42% of early introduction group (EIG) children met the per-protocol criteria.

OBJECTIVE

We sought to identify which factors were responsible for nonadherence in the EAT study.

METHODS

Factors influencing adherence within the key early introduction period in the EIG (up to 6 months of age) were divided into enrollment and postenrollment factors, and their association with nonadherence was explored.

RESULTS

In an adjusted analysis, at enrollment, increased maternal age, nonwhite ethnicity, and lower maternal quality of life were independently and significantly associated with overall nonadherence in the EIG. Enrollment eczema and enrollment serum allergen-specific IgE sensitization to 1 or more foods (≥0.1 kU/L) were not related to overall nonadherence. After enrollment, 2 factors were significantly related to EIG overall nonadherence: parent-reported IgE-type symptoms with infant allergenic food consumption by 6 months of age and reported feeding difficulties by 4 months of age.

CONCLUSION

If early introduction of allergenic foods were to be considered a strategy to prevent food allergy, families of nonwhite ethnicity, those with older mothers, and those with infants with reported feeding difficulties or early-onset eczema would benefit from support to promote early and sustained consumption.

Challenges experienced with early introduction and sustained consumption of allergenic foods in the Enquiring About Tolerance (EAT) study: A qualitative analysis

BACKGROUND

The early introduction group participants of the Enquiring About Tolerance study were asked to undertake a proscriptive regimen of early introduction and sustained consumption of 6 allergenic foods. It was envisaged that this might be challenging, and early introduction group families were presented with an open-text question to express any problems they were experiencing with the regimen in recurring online questionnaires.

OBJECTIVE

We sought to analyze these open-text questionnaire responses with the aim of identifying challenges associated with the introduction and regular consumption of allergenic foods.

METHODS

Three combinations of interim questionnaire responses were selected for analysis, representing the early period (4, 5, and 6 months), middle period (8 and 12 months), and late period (24 and 36 months) of participation in the Enquiring About Tolerance study. Responses were assigned a code to describe their content and subsequently grouped into themes to portray key messages. A thematic content analysis allowed for conversion of qualitative codes into quantitative summaries.

RESULTS

Three main challenges to allergenic food consumption were identified. First, some children refused the allergenic food, causing a sense of defeat among caregivers. Second, caregivers were concerned that allergenic foods might be causing a reaction, triggering a need for reassurance. Third, practical problems associated with the regimen compromised caregivers' capacity to persist.

CONCLUSION

Understanding the challenges experienced with allergenic food introduction and sustained consumption is the necessary precursor to developing specific communication and support strategies that could be used by caregivers, practitioners, policymakers, and key stakeholders to address these problems.

Earlier ingestion of peanut after changes to infant feeding guidelines: The EarlyNuts study

BACKGROUND

Randomized controlled trials demonstrate that timely introduction of peanut to infants reduces the risk of peanut allergy. However, much debate remains regarding how to best achieve earlier peanut introduction at the population level. Our previous study in 2007-2011 (HealthNuts, n = 5300) indicated that few infants were consuming peanut in the first year. Australian infant feeding guidelines were updated in 2016 to recommend introducing peanut before 12 months for all infants. There were no data available on the subsequent effect on peanut introduction or peanut reactions.

OBJECTIVE

We sought to assess the consequences of a nonscreening approach to allergenic food introduction in a population-based sample of infants in their first year of life.

METHODS

EarlyNuts is a population-based, cross-sectional study of 12-month-old infants in Melbourne, Australia, recruited by using an identical sampling frame and methods to HealthNuts (72% response rate vs 73% response rate in HealthNuts). We report here on the first 860 participants recruited between November 2016 and October 2018.

RESULTS

Most infants (88.6%; 95% CI, 86.1% to 90.7%) had introduced peanut by 12 months (median age, 6 months), an increase from 28.4% (95% CI, 27.2% to 29.7%) in the HealthNuts study. By 12 months, the majority of these (76.4%) had consumed peanut more than 4 times, and 28% were eating peanut more than once per week. Preliminary results on parent-reported reactions show that 4.0% of those consuming peanut by 12 months had possible IgE-mediated reactions.

CONCLUSIONS

There has been a striking shift toward earlier peanut introduction, with a 3-fold increase in peanut introduction by age 1 year in 2018 compared with 2007-2011.

Non-IgE-mediated gastrointestinal allergies-Do they have a place in a new model of the Allergic March

The rise in food allergy has been described as the "second wave" of the allergy epidemic, with some developed countries reporting a prevalence of 10% of challenge-proven food allergies. Recognition of the Allergic March has played a crucial role in identifying causality in allergic conditions, linking atopic dermatitis to food allergy and food allergy to other atopic disorders, thereby highlighting opportunities in prevention and the importance of early intervention. This publication will establish the value of weaving the less well-understood, non-IgE-mediated food allergy into the Allergic March and mapping its progression through childhood and its associated co-morbidities. The proposed non-IgE-mediated Allergic March highlights the concomitant presentation of gastrointestinal symptoms and atopic dermatitis as early presenting symptoms in confirmed non-IgE-mediated allergies and the later development of atopic co-morbidities, including asthma and allergic rhinitis, similar to the IgE-mediated Allergic March. This publication highlights recent observations of a link between non-IgE-mediated food allergy in early childhood and functional gastrointestinal disorders in later life and also the reported occurrence of extra-intestinal manifestations at later ages. Although significant limitations exist in regard to the proposed evolution of the Allergic March model, the authors hope that this publication will influence the management of non-IgE-mediated gastrointestinal allergies and inform future research and interventions.

Factors Affecting Vitamin D Status in Infants

Vitamin D is critical to children's skeletal development and health. Despite this, the factors which determine vitamin D concentrations during infancy remain incompletely understood. This article reviews the literature assessing the factors which can affect vitamin D status in infancy, including antenatal and postnatal vitamin D supplementation. Observational data supports that dietary intake of vitamin D, UV exposure, and geographic factors contribute significantly to infants' vitamin D status, but the relationship is unclear regarding genetic variation, ethnicity, and maternal vitamin D status. Randomised controlled trials have compared higher versus lower doses of infant vitamin D supplementation, but no studies have compared infant vitamin D supplementation to placebo and eliminated external sources of vitamin D to fully quantify its effect on vitamin D status. Knowledge gaps remain regarding the factors associated with optimal vitamin D concentrations in infants-including key factors such as ethnicity and genetic variation-and further studies are needed.

Caregiver and expecting caregiver support for early peanut introduction guidelines

BACKGROUND

Recent guidelines recommend early peanut introduction (EPI) beginning around 4 to 6 months of age in infants with severe eczema and/or egg allergy and around 6 months for all other infants. Caregiver preferences for such practices are unknown.

OBJECTIVE

To determine levels of support for early allergenic solid food recommendations among new and expecting caregivers of infants at risk for peanut allergy.

METHODS

We explored preferences for EPI and in-office allergy risk assessment (IRA) through a nationally representative survey of expecting (n = 1,000) and new caregivers of infants younger than 1 year (n = 1,000).

RESULTS

Among a primarily female (99.7%), married (80.3%), and white (74.4%) sample, 29% had no or vague awareness of the new guidelines, 61% had no or minimal concern for their child developing food allergy, but 54% felt timing of food introduction has moderate to strong importance for developing food allergy. Only 31% expressed willingness for EPI before or around 6 months of age, with 40% reporting willingness to introduce peanut after 11 months of age, similar to tree nuts and seafood. However, 60% reported willingness to introduce egg before 8 months of age. A total of 51% and 56.8% were unwilling to allow IRA methods, such as skin testing and oral challenge, before 11 months of age, respectively. Odds of willingness to delay peanut introduction (odds ratio, 0.79; 95% confidence interval, 0.65-0.96) and undergo challenge (odds ratio, 0.67; 95% confidence interval, 0.54-0.82) after 6 months of age were lower among expecting caregivers.

CONCLUSION

Among new and expecting caregivers, there is poor current willingness and questionable support for early allergenic solid food recommendations, including IRA before introduction. Willingness was better among expecting vs current caregivers. These trends underscore a need for broader formal implementation planning to facilitate early allergen introduction and maximize its preventive benefits.

Food allergy

Food allergies manifest in a variety of clinical conditions within the gastrointestinal tract, skin and lungs, with the most dramatic and sometimes fatal manifestation being anaphylactic shock. Major progress has been made in basic, translational and clinical research, leading to a better understanding of the underlying immunological mechanisms that lead to the breakdown of clinical and immunological tolerance against food antigens, which can result in either immunoglobulin E (IgE)-mediated reactions or non-IgE-mediated reactions. Lifestyle factors, dietary habits and maternal-neonatal interactions play a pivotal part in triggering the onset of food allergies, including qualitative and quantitative composition of the microbiota. These factors seem to have the greatest influence early in life, an observation that has led to the generation of hypotheses to explain the food allergy epidemic, including the dual-allergen exposure hypothesis. These hypotheses have fuelled research in preventive strategies that seek to establish desensitization to allergens and/or tolerance to allergens in affected individuals. Allergen-nonspecific therapeutic strategies have also been investigated in a number of clinical trials, which will eventually improve the treatment options for patients with food allergy.

Use of infant formula in the ELFE study: The association with social and health-related factors

Breastfeeding is recommended until 6 months of age, but a wide range of infant formula is available for nonbreastfed or partially breastfed infants. Our aim was to describe infant formula selection and to examine social- and health-related factors associated with this selection. Analyses were based on 13,291 infants from the French national birth cohort Etude Longitudinale Française depuis l'Enfance. Infant diet was assessed at Month 2 by phone interview and monthly from Months 3 to 10 via internet/paper questionnaires. Infant formulas were categorized in 6 groups: extensively or partially hydrolysed, regular with or without prebiotics/probiotics, and thickened with or without prebiotics/probiotics. Associations between type of infant formula used at 2 months and family or infant characteristics were assessed by multinomial logistic regressions. At Month 2, 58.1% of formula-fed infants were fed with formula enriched in prebiotics/probiotics, 31.5% with thickened formula, and 1.4% with extensively hydrolysed formula. The proportion of formula-fed infants increased regularly, but the type of infant formula used was fairly stable between 2 and 10 months. At Month 2, extensively hydrolysed formulas were more likely to be used in infants with diarrhoea or regurgitation problems. Partially hydrolysed formulas were more often used in families with high income, with a history of allergy, or with infants with regurgitation issues. Thickened formulas were used more with boys, preterm infants, infants with regurgitation issues, or in cases of early maternal return to work. The main factors related to the selection of infant formula were family and infant health-related ones.

Primary Prevention of Food Allergy

PURPOSE OF REVIEW

This article summarises recent developments on the prevention of food allergy in terms of the 5 D's of the development of food allergy: dry skin, diet, dogs, dribble, and vitamin D.

RECENT FINDINGS

While several advances have improved our understanding of the development of food allergy, few preventive strategies have been implemented beyond changes in infant feeding guidelines. These now state that the introduction of allergenic solids such as peanuts should occur in the first year of life. Results from randomised controlled trials on other allergenic solids, vitamin D supplementation, BCG immunisation at birth and eczema prevention are eagerly anticipated in order to inform further preventative strategies.

Prevention of Food Allergies

This review summarizes the current state of play with regard to food allergy prevention. Food allergy prevention strategies focused on promoting timely introduction of allergenic foods (predominantly peanut) into the infant diet have recently been introduced in several countries. Additional prevention strategies currently under investigation include optimizing infant vitamin D levels, modulating the gut microbiota through use of probiotics, and preventing eczema to reduce the risk of food sensitization through a damaged skin barrier.

Advice about infant feeding for allergy prevention: A confusing picture for Australian consumers?

AIM

Early feeding plays an important role in programming the immune system, particularly the risk of food allergy. There are many infant feeding guides published for consumers available in Australia, with most based on the National Health and Medical Research Council (NHMRC) 2012 Infant Feeding Guidelines for Health Workers and the Australasian Society of Clinical Immunology and Allergy (ASCIA) Infant Feeding Advice for allergy prevention. We sought to compare allergy-specific content of infant feeding educational material written for parents with these two documents.

METHODS

Australian websites of children's hospitals, early child health organisations and consumer groups providing information about diet during pregnancy, breastfeeding and early infancy were compared with NHMRC and ASCIA guidelines.

RESULTS

Twenty-five sets of infant feeding information were identified. Food allergy was discussed in 18 resources. Recommended length of exclusive breastfeeding and timing of commencing solid foods was consistently around 6 months, with some variation in wording. Advice regarding to include and not delay introduction of common allergens into babies' diets was generally consistent with NHMRC and ASCIA recommendations, however the audit identified some resources that still recommended delayed introduction of common allergens.

CONCLUSION

As consumers have access to a plethora of health information it is imperative that information about infant feeding from health-care authorities is simple, evidence-based and consistent to avoid confusion. Use of consensus wording related to infant feeding guidelines to prevent allergies will provide clear messages related to the timing of introduction to solid foods and inclusion of allergens in the early diet.

Low Food Allergy Prevalence Despite Delayed Introduction of Allergenic Foods-Data from the GUSTO Cohort

BACKGROUND

There is mounting evidence that early introduction of allergenic food decreases the risk of food allergy development, especially in high-risk infants with eczema. However, there is a lack of data to suggest whether this association holds true in Asian populations.

OBJECTIVE

To investigate the relationship between the timing of introduction of allergenic foods and food allergy outcomes in infants in the Growing Up in Singapore Towards healthy Outcomes (GUSTO) study.

METHODS

The GUSTO cohort recruited 1152 mothers of Chinese, Malay, and Indian ethnicity who had singleton, naturally conceived pregnancies and followed their offspring prospectively. Information on demographic characteristics, child health, infant feeding practices, and a convincing history of IgE-mediated food allergy was obtained from interviewer-administered questionnaires at multiple time points. Corroborative skin prick tests to food allergens were performed at 18 and 36 months.

RESULTS

Most of the infants were introduced to egg (49.6%), peanut (88.7%), and shellfish (90.2%) after age 10 months. Food allergy prevalence was, however, very low between age 12 and 48 months: egg, 0.35% to 1.8%; peanut allergy, 0.1% to 0.3%; and shellfish, 0.2% to 0.9%. There were no significant associations between the timing of introduction of allergenic foods and the development of food allergy, adjusted for confounders including breast-feeding and eczema.

CONCLUSIONS

Food allergy rates in Singapore are low despite delayed introduction of allergenic foods. Early introduction of allergenic foods may thus not be necessary in populations in which overall food allergy prevalence is low, and thus infant feeding recommendations should be carefully tailored to individual populations.

Primary Prevention of Food Allergy

Food allergy is estimated to affect approximately 8% of children in the USA. This is a disease without any known treatment or cure and, for some, a disease that can be quite severe, even life-threatening. While recent advances in potential treatment have made remarkable strides, with two food-targeted immunotherapy products now in phase III trials, perhaps the biggest gains in the field have come in the advent of potential preventative strategies to avoid the development of food allergy in high-risk individuals. There have been multiple, randomized, controlled trials (RCTs) performed in the past 5 years that have demonstrated significant risk reduction from early allergen introduction. These include two trials for early peanut introduction and five trials for early egg introduction in the first year of life. The results indicate that primary prevention of food allergy through early allergen introduction may represent a strategy that could potentially avert tens of thousands of children from becoming food allergic. In support of the data for peanut, the National Institute of Allergy and Infectious Diseases recently sponsored an addendum to the 2010 food allergy guidelines, specifically recommending peanut be introduced in both high- and standard-risk infants to reduce the risk of developing peanut allergy. To date, no formal recommendations have been made for egg, however. This review will focus on the latest evidence supporting early introduction as a strategy to prevent food allergy, as well as on practical aspects for its successful implementation.

The prevalence of food allergy and other allergic diseases in early childhood in a population-based study: HealthNuts age 4-year follow-up

BACKGROUND

The HealthNuts study previously reported interim prevalence data showing the highest prevalence of challenge-confirmed food allergy in infants internationally. However, population-derived prevalence data on challenge-confirmed food allergy and other allergic diseases in preschool-aged children remain sparse.

OBJECTIVE

This study aimed to report the updated prevalence of food allergy at age 1 year from the whole cohort, and to report the prevalence of food allergy, asthma, eczema, and allergic rhinitis at age 4 years.

METHODS

HealthNuts is a population-based cohort study with baseline recruitment of 5276 one-year-old children who underwent skin prick test (SPT) to 4 food allergens and those with detectable SPT results had formal food challenges. At age 4 years, parents completed a questionnaire (81.3% completed) and those who previously attended the HealthNuts clinic at age 1 year or reported symptoms of a new food allergy were invited for an assessment that included SPT and oral food challenges. Data on asthma, eczema, and allergic rhinitis were captured by validated International Study of Asthma and Allergies in Childhood questionnaires.

RESULTS

The prevalence of challenge-confirmed food allergy at age 1 and 4 years was 11.0% and 3.8%, respectively. At age 4 years, peanut allergy prevalence was 1.9% (95% CI, 1.6% to 2.3%), egg allergy was 1.2% (95% CI, 0.9% to 1.6%), and sesame allergy was 0.4% (95% CI, 0.3% to 0.6%). Late-onset peanut allergy at age 4 years was rare (0.2%). The prevalence of current asthma was 10.8% (95% CI, 9.7% to 12.1%), current eczema was 16.0% (95% CI, 14.7% to 17.4%), and current allergic rhinitis was 8.3% (95% CI, 7.2% to 9.4%). Forty percent to 50% of this population-based cohort experienced symptoms of an allergic disease in the first 4 years of their life.

CONCLUSIONS

Although the prevalence of food allergy decreased between age 1 year and age 4 years in this population-based cohort, the prevalence of any allergic disease among 4-year-old children in Melbourne, Australia, is remarkably high.

An Australian Consensus on Infant Feeding Guidelines to Prevent Food Allergy: Outcomes From the Australian Infant Feeding Summit

BACKGROUND

Infant feeding in the first postnatal year of life has an important role in an infant's risk of developing food allergy. Consumer infant feeding advice is diverse and lacks consistency.

AIM

The Australian Infant Feeding Summit was held with the aim of achieving national consensus on the wording of guidelines for infant feeding and allergy prevention.

METHODS

Two meetings were hosted by the Centre for Food and Allergy Research, the Australasian Society of Clinical Immunology and Allergy, and the Australian National Allergy Strategy. The first meeting of 30 allergy researchers, clinicians, and consumers assessed the evidence. The second consensus meeting involved 46 expert stakeholders including state and federal health care agencies, consumers, and experts in allergy, infant feeding, and population health.

RESULTS

Partner stakeholders agreed on consensus wording for infant feeding advice: CONCLUSIONS: Consensus was achieved in a context in which there is a high prevalence of food allergy. Guidelines for other countries are being updated. Provision of consistent wording related to infant feeding to reduce food allergy risk will ensure clear consumer advice.

Guidance on the risk assessment of substances present in food intended for infants below 16 weeks of age

Following a request from the European Commission to EFSA, the EFSA Scientific Committee (SC) prepared a guidance for the risk assessment of substances present in food intended for infants below 16 weeks of age. In its approach to develop this guidance, the EFSA SC took into account, among others, (i) an exposure assessment based on infant formula as the only source of nutrition; (ii) knowledge of organ development in human infants, including the development of the gut, metabolic and excretory capacities, the brain and brain barriers, the immune system, the endocrine and reproductive systems; (iii) the overall toxicological profile of the substance identified through the standard toxicological tests, including critical effects; (iv) the relevance for the human infant of the neonatal experimental animal models used. The EFSA SC notes that during the period from birth up to 16 weeks, infants are expected to be exclusively fed on breast milk and/or infant formula. The EFSA SC views this period as the time where health-based guidance values for the general population do not apply without further considerations. High infant formula consumption per body weight is derived from 95th percentile consumption. The first weeks of life is the time of the highest relative consumption on a body weight basis. Therefore, when performing an exposure assessment, the EFSA SC proposes to use the high consumption value of 260 mL/kg bw per day. A decision tree approach is proposed that enables a risk assessment of substances present in food intended for infants below 16 weeks of age. The additional information needed when testing substances present in food for infants below 16 weeks of age and the approach to be taken for the risk assessment are on a case-by-case basis, depending on whether the substance is added intentionally to food and is systemically available.

Changes to infant feeding guidelines: Relevance to dermatologists

The newly revised Australian Infant Feeding Guidelines recommends that all infants, including those at high risk of allergy, be introduced foods traditionally considered allergenic (such as peanut butter, dairy, wheat and egg) within the first year of life. High-risk infants are those with early onset eczema (<3-months old) or with moderate to severe eczema not responding to treatment (<6-months old). Eczema can also represent a symptom of allergy presentation and the recommended introduction of some foods in this group may lead to allergic reactions at home. Although there have been no reported deaths from gradual food introduction to infants at home and cohort studies have only reported mild to moderate reactions, there is anecdotal evidence that more severe reactions can occur rarely. Allergic reactions, even if they are not life-threatening, can be a terrifying experience for parents. Dermatologists play an important role when dealing with high-risk infants in promoting the message of early allergenic food introduction yet also instigating appropriate allergy testing when necessary. This short review aims to provide an update to Australasian dermatologists on the newly revised Australian Infant Feeding Guidelines and provide a food allergy screening pathway for high-risk infants prior to commencement of allergenic foods.

The Impact of Timing of Introduction of Solids on Infant Body Mass Index

OBJECTIVES

To evaluate the associations between breastfeeding duration, age at solids introduction, and their interaction in relation to infant (age 9-15 months) above normal body mass index (BMI).

STUDY DESIGN

Cross-sectional, population-based study with 3153 infants from Melbourne (2007-2011). Above normal BMI (z score > 2, equivalent to >97.7th percentile) defined using the World Health Organization standard.

RESULTS

Both longer duration of full and any (full or partial) breastfeeding were associated with lower odds of above normal BMI (eg, aOR, 0.37 [95% CI, 0.22-0.60] for full breastfeeding 4-5 months versus 0-1 months). Compared with introduction of solids at 5-6 months, both early and delayed introduction were associated with increased odds of above normal BMI (aOR for 4 months, 1.75 [95% CI, 1.10-2.80] and for ≥7 months, 2.64 [95% CI, 1.26-5.54] versus 6 months). Such associations differ by breastfeeding status at 4 months (interaction P = .08). Early introduction of solids was associated with increased odds of above normal BMI in both infants fully or partially breastfed for ≥4 months (aOR, 3.66; 95% CI, 1.41-9.51) and those breastfed for <4 months (aOR, 3.11; 95% CI, 1.39-6.97). Introduction of solids at ≥7 months was associated with increased odds of above normal BMI (aOR, 5.79; 95% CI, 1.91-17.49) among infants breastfed for <4 months only.

CONCLUSION

Introduction of solids at 5-6 months, compared with either early or delayed introduction, is associated with decreased odds of above normal BMI at 1 year of age, regardless of infants' breastfeeding status at 4 months. These results may have implications for public health guidelines with regard to recommendations about the optimal timing of the introduction of solid foods in infancy.

Epidemiology of food allergy and food-induced anaphylaxis: is there really a Western world epidemic?

PURPOSE OF REVIEW

Food-induced anaphylaxis continues to be an important cause of hospital admissions, particularly in children. This review outlines recent advances in understanding the epidemiology of IgE-mediated food allergy and potential mechanisms for its rise in prevalence.

RECENT FINDINGS

The rise in food allergy prevalence in Western countries has happened more quickly than changes to the genome can occur; thus, environmental changes are likely to be important. Recent studies, however, suggest that genetic risk determines responses to environmental risk factors. Environmental peanut exposure has been associated with increased peanut allergy risk in individuals with filaggrin null mutations, consistently with sensitization occurring through a damaged skin barrier. Reduced microbial and vitamin D exposure is also leading candidates for risk factors for food allergy in the context of genetic susceptibility. In addition, HLA-DR and HLA-DQ gene region variants appear to play a role in peanut allergy, although no studies have yet assessed their susceptibility to environmental cues. Finally, findings from observational cohorts and the first large-scale intervention trials for food allergy prevention support early oral allergen exposure to reduce the prevalence of specific food allergies, which is informing changes in public health guidelines at the population level. Further research will be required to assess the impact of these guideline changes on the population prevalence of food allergy.

SUMMARY

New studies are providing important insights into the prevalence, causes, and mechanisms of food allergy. Recent findings are informing changes to population health guidelines in developed countries, which have the potential to halt or reverse the increase in food allergy prevalence. By contrast, food allergy in the developing world remains understudied.

Understanding the feasibility and implications of implementing early peanut introduction for prevention of peanut allergy

BACKGROUND

A recent randomized trial (the Learning Early About Peanut Allergy [LEAP] study) provided evidence that earlier dietary peanut introduction reduces peanut allergy prevalence in high-risk infants. However, questions remain as to how to identify and target the "at-risk" population to facilitate timely introduction of peanut.

OBJECTIVE

We sought to use population-based infant peanut allergy data to understand feasibility and implications of implementing the LEAP trial intervention.

METHODS

Using the HealthNuts study cohort (n = 5276) of 1-year-old infants, we explored the impact of using various criteria to identify infants at high risk of developing peanut allergy, and the implications of skin prick test (SPT) screening before peanut introduction.

RESULTS

Screening all infants with early onset eczema and/or egg allergy could require testing 16% of the population and would still miss 23% of peanut allergy cases; 29% of screened infants would require clinical follow-up because of being SPT-positive. Around 11% of high-risk infants were excluded from the LEAP study because of an SPT wheal size of more than 4 mm to peanut at baseline; data from the HealthNuts study suggest that 80% of these would be peanut allergic on food challenge. There were no life-threatening events among either low- or high-risk infants whose parents chose to introduce peanut at home in the first year of life, or in 150 peanut-allergic infants during hospital-based challenges.

CONCLUSIONS

Based on this large epidemiological study, a population program aiming to identify and screen all infants at risk of peanut allergy would pose major cost and logistic challenges that need to be carefully considered. Further research might be required to provide data for low-risk infants.

Why Does Australia Appear to Have the Highest Rates of Food Allergy?

Australia has reported the highest rates of food allergy, using the gold standard, oral food challenge. This phenomenon, which appears linked to the "modern lifestyle" and has coincided with the explosion of the new diseases of affluence in the 21st century, dubbed "affluenza," has spurred a multitude of theories and academic investigations. This review focuses on potentially modifiable lifestyle factors for the prevention of food allergy and presents the first data to emerge in the Australian context that centers around the dual allergen exposure hypothesis, the vitamin D hypothesis, and the hygiene hypothesis.

The Learning Early About Peanut Allergy Study: The Benefits of Early Peanut Introduction, and a New Horizon in Fighting the Food Allergy Epidemic

Observational studies have explored associations between timing of peanut, egg, and milk introduction and food allergy development, noting significant associations with reduced respective rates of milk, egg, and peanut allergy associated with earlier timing of introduction. Interventional studies developed to more definitively explore these outcomes have been published for egg and peanut, and are ongoing for multiple other allergens. This review focuses on the recent publication regarding the LEAP (Learning Early About Peanut Allergy) study, its highly favorable results, the policy implications of its findings, and the horizon for primary prevention as a realistic strategy to prevent food allergy.

Current developments for improving efficacy of allergy vaccines

Allergic diseases are prevalent worldwide. Allergen immunotherapy (AIT) is a current treatment for allergy, leading to modification of the natural course of disease. Mechanisms of efficacy include Treg through release of IL-10 and TGF-β and specific IgG4 blocking antibodies. Subcutaneous and sublingual routes are popular, but uptake is limited by inconvenience and safety concerns. Inclusion criteria limit application to a small proportion of allergic patients. New forms of immunotherapy are being investigated for more efficacious, convenient and safer options with promising advances in recent years. The rationale of reducing vaccine allergenicity to increase safety while improving immunogenicity led to investigation of T-cell epitope-based peptides and recombinant allergen derivatives. Additionally, different routes of administration and adjuvants and adjunct therapies are being explored. This review discusses the current status of AIT and recent advances to improve clinical efficacy, safety and long-term immune tolerance.

Advances in allergic skin disease, anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects in 2014

This review highlights some of the research advances in anaphylaxis; hypersensitivity reactions to foods, drugs, and insects; and allergic skin diseases that were reported in the Journal in 2014. Studies on food allergy suggest worrisomely high rates of peanut allergy and food-induced anaphylaxis-related hospitalizations. Evidence is mounting to support the theory that environmental exposure to peanut, such as in house dust, especially with an impaired skin barrier attributed to atopic dermatitis (AD) and loss of function mutations in the filaggrin gene, is a risk factor for sensitization and allergy. Diagnostic tests are improving, with early studies suggesting the possibility of developing novel cellular tests with increased diagnostic utility. Treatment trials continue to show the promise and limitations of oral immunotherapy, and mechanistic studies are elucidating pathways that might define the degree of efficacy of this treatment. Studies have also provided insights into the prevalence and characteristics of anaphylaxis and insect venom allergy, such as suggesting that baseline platelet-activating factor acetylhydrolase activity levels are related to the severity of reactions. Advances in drug allergy include identification of HLA associations for penicillin allergy and a microRNA biomarker/mechanism for toxic epidermal necrolysis. Research identifying critical events leading to skin barrier dysfunction and the polarized immune pathways that drive AD have led to new therapeutic approaches in the prevention and management of AD.

Cohort Profile: The HealthNuts Study: Population prevalence and environmental/genetic predictors of food allergy

HealthNuts is a single-centre, multi-wave, population-based longitudinal study designed to assess prevalence, determinants, natural history and burden of allergy (particularly food allergy) in the early years of life. It is novel in the use of serial food challenge measures within its population frame to confirm food allergy. The cohort comprises 5276 children initially recruited at age 12 months from council-run immunization sessions across Melbourne, Australia. As well as parent-completed questionnaires and researcher-observed eczema status, all infants underwent skin-prick testing to egg, peanut, sesame and either cow's milk or shellfish, and those with detectable wheals underwent food challenges to determine clinical allergy. In wave 2, conducted at age 4 years, validated questionnaires collected data on asthma, allergic rhinitis (hay fever), eczema and food allergies. Food challenges were repeated in children previously identified as food allergic to determine resolution. In wave 3, all children (irrespective of food allergy status) were invited for clinical assessment at age 6 years, including lung function, physical measurements, skin-prick testing to foods and aeroallergens and food challenges if food sensitized. Biological specimens (blood, cheek swabs) were collected at each wave for ancillary immunological, genetic and epigenetic studies. Applications to access data and/or samples can be submitted to [katrina.allen@mcri.edu.au].

A novel approach used outcome distribution curves to estimate the population-level impact of a public health intervention

OBJECTIVES

To provide an analytical framework within which public health interventions can be evaluated, present its mathematical proof, and demonstrate its use using real trial data.

STUDY DESIGN AND SETTING

This article describes a method to assess population-level effects by describing change using the distribution curve. The area between the two overlapping distribution curves at baseline and follow-up represents the impact of the intervention, that is, the proportion of the target population that benefited from the intervention.

RESULTS

Using trial data from a parenting program, empirical proof of the idea is demonstrated on a measure of behavioral problems in 355 preschoolers using the Gaussian distribution curve. The intervention group had a 12% [9%-17%] health gain, whereas the control group had 3% [1%-7%]. In addition, for the subgroup of parents with lower education, the intervention produced a 15% [6%-25%] improvement, whereas for the group of parents with higher education the net health gain was 6% [4%-16%].

CONCLUSION

It is possible to calculate the impact of public health interventions by using the distribution curve of a variable, which requires knowing the distribution function. The method can be used to assess the differential impact of population interventions and their potential to improve health inequities.