Regional distribution of food allergy in Australia
Hypoallergenic infant formulas are used to help prevent and treat allergic diseases in babies and young children. A study carried out in Australia has investigated the pattern of prescription rates of hypoallergenic formula for children aged 0-2 years throughout the country as a means of gaining more information on the regional distribution of food allergy in Australia.
Results showed significant regional variation in hypoallergenic formula prescription rates throughout the country.
Data was obtained from the Australian Department of Health and Aging and the Australian Bureau of Statistics for the 52 statistical divisions in mainland Australia, plus Tasmania.
Geographical factors (decreasing latitude and increasing longitude) were associated with a higher rate of hypoallergenic formula prescriptions, such that rates were higher in southern compared to northern regions, and in eastern compared with western regions. The highest rates of prescription were found to be in southern Australia (14,406 per 100,000 population/yr) and the lowest was in the north (721), compared with a national average of 4099.
Even after controlling for a number of factors such as longitude, physician density and markers of socioeconomic status, southern latitudes and eastern longitudes were associated with higher hypoallergenic formula prescription rates.
The authors conclude that these data provide support for a possible role of sun exposure/vitamin D status (amongst other potential factors) in the pathogenesis of food allergy.
Reference: Mullins et al. 2009. Pediatric Allergy and Immunology. Doi 10.1111/j.1399-3038.2009.00962.x
New projects supported by the Coeliac Research Fund
The Coeliac Research Fund in Australia has announced the successful grant recipients of the 2009 Grants Program, with seed funding going to support three new research projects over the coming year.
The three research projects include a study into plant enzyme therapy for managing coeliac disease; measurement of the subtle neurological effects of eating gluten in those with coeliac disease; and an investigation into whether immune tolerance is abnormal in coeliac disease.
The first study, to be carried out by scientists at Melbourne Health, will comprise a six week trial treatment whereby the effectiveness of the plant enzyme supplementation will be evaluated. A group of volunteers will eat gluten plus the supplement, whilst another group will be given a placebo. The changes in the gut will be monitored and villous atrophy assessed before and after the research period.
The second study will be conducted by a team at Monash University’s Department of Gastroenterology. The project will look for an association between subtle neurological deficits such as fatigue, difficulty concentrating, poor memory and coordination, and gluten exposure. The results are likely to have significant implications for the quality of life in patients with coeliac disease before and after diagnosis, and help to qualify the ‘fuzzy’ feeling reported by many with coeliac disease.
The third study is a collaboration between Associate Professor Tony Kelleher and researchers at St Vincent’s Centre for Applied Immunology in Sydney and Dr Bob Anderson and his team at the Walter and Eliza Hall Institute, Melbourne. Although approximately 1 in 3 people carry the essential susceptibility genes for coeliac disease, only 1 in 100 actually develop coeliac disease. The reason for this is unknown however it is thought that environmental factors influence the balance between a destructive pro-inflammatory and a tolerant immune response to gluten. The study is designed to gain a greater understanding of the immune tolerance to gluten.
More information on the Coeliac Research Fund’s grant program, and the research supported by the fund, can be found at www.coeliacresearchfund.org
EuroPrevall study on food allergies in China, India and Russia
One of the aims of the EuroPrevall project is to gain a greater understanding of the global variations in food allergy prevalence. The EuroPrevall-INCO project has been developed to evaluate the prevalence of food allergies in China, India and Russia using the standardised methodology of the EuroPrevall protocol used for studies in the European Union. The research team have recently published their study methodology in the journal ‘Allergy’.
More than 37,000 children primary schoolchildren were randomly recruited from urban and rural regions of China, Russia and India and screened to ascertain possible adverse reactions to foods. More than 3,000 cases of children with adverse reactions, and controls were then selected to answer a detailed questionnaire designed to evaluate the possible risk factors of food allergies. Objective evidence of sensitisation including skin-prick test and serum specific IgE measurement was collected and further confirmation of food allergies by double blind food challenge was also conducted.
The findings of the study have not yet been published, however the authors maintain this will be the first comparative study of the epidemiology of food allergies in China, India, and Russia using the same standardised methodology as that used in studies conducted by the EuroPrevall project team in the European Union.
Reference: Wong et al. 2009. Allergy. Doi: 10.1111/j.1398-9995.2009.02214.x
Predicting food allergy development in children
Identification of early and efficient markers for later development of food allergy would be a very useful tool in the management of food allergy. Researchers in Germany have examined the usefulness of repeated measurements of food sensitisation in early childhood for predicting doctor-diagnosed food allergy at the age of six years.
Data for 1082 children collected from a prospective birth cohort study were analysed to determine food allergy predictability. Information for the study was collected by parental questionnaires, and blood samples were obtained at two and six years of age. Children with repeated determination of sensitisation to food allergens at two and six years of age were categorised into four sensitisation phenotypes: no, early onset, late onset and persistent sensitisation.
Children with early onset food allergen sensitisation (in the first two years of life) were found to have a high risk of developing doctor-diagnosed food allergy at six years. Persistent food allergen sensitisation during the early childhood years was also found to be associated with an increased risk of doctor-diagnosed food allergy at six years.
Those children who exhibited food sensitisation in their first two years of life, and also had a history of parental atopy showed the highest risk for doctor-diagnosed food allergy at six years. Such symptoms of food sensitisation in early childhood indicate that attention should be paid to the potential development of food allergy-related symptoms in later years.
Reference: Schnabel et al. 2009. Clinical and Experimental Allergy. DOI: 10.1111/j.1365-2222.2009.03400.x
UK Food Standards Agency pamphlet on food allergies
An advice leaflet for people who have been newly diagnosed with a food allergy has been published by the UK Food Standards Agency in collaboration with six allergy and nutrition organisations.
The leaflet, ‘Buying food when you have a food allergy or intolerance’, guides people with a food allergy or intolerance, including coeliac disease, through the steps to remember when buying food and when eating out.
The topics covered include:
- checking the label on pre-packed food
- what to look out for when foods aren’t pre-packed
- talking to restaurant staff about your allergy
- what to watch out for when using self-service restaurants
The Agency worked closely with Allergy UK, the Anaphylaxis Campaign, the British Dietetic Association, the British Nutrition Foundation, Coeliac UK and Foods Matter to produce the leaflet.
Sue Hattersley, Head of the Agency’s Food Allergy Branch, said: “We have worked very closely with all of the major food allergy support groups and many of our leading allergy consultants to ensure that newly diagnosed patients receive consistent and reliable advice. We hope that consumers diagnosed with a food allergy or intolerance will find the leaflet a useful checklist to refer to when buying food.”
The leaflet can be downloaded from the Food Standards Agency website.
Allergic disease burden in Scotland
There are reportedly few reliable data on the overall allergic disease burden in Scotland, yet there are ongoing concerns about the quality of care provided to patients with allergic disorders in that country.
In a new piece of research, epidemiologists have undertaken the most comprehensive review of incidence, prevalence and outcome of allergic disorders in Scotland to-date. In the same study, the researchers aimed to investigate ethnic variations in the epidemiology and outcomes from allergic disorders in Scotland and to estimate the country’s national healthcare costs associated with allergies.
The study focussed on the following conditions: food allergy; allergic conjunctivitis; allergic rhinitis; anaphylaxis; angioedema; asthma; drug allergy; eczema/atopic dermatitis; urticaria; and allergies not classified elsewhere. Data was obtained from national surveys, primary care data, prescribing and medication data, hospital admissions data and mortality data.
The data showed there were 12,210 incident cases of allergy in primary care in 2003–2004. Allergic disorders have been found to affect about one in three people in Scotland at some time in their lives, with eczema having the highest incidence. Over 4% of all GP consultations and 1.5% of hospital admissions were due to allergic disorders. There were 100 asthma deaths in 2005 (20 per million people). Data on ethnicity was either not available or too small to be analysed appropriately.
In terms of economic burden, the direct healthcare costs for allergic disorders were estimated at around £130 million per year, with the majority of these costs being related to asthma.
The study authors believe that since a very high proportion of children in Scotland now live with allergies, the disease burden associated with these conditions is likely to persist for many decades. They also recommend continued monitoring of allergic disease trends to provide the data needed to inform clinical studies of allergic disease prevention and management.
Reference: Anandan et al. 2009 J R Soc Med. Vol 102 pp. 431-442.
Peanut allergy inherited from allergic mothers
Researchers at the Mount Sinai School of Medicine in New York, USA, have used a mouse model to gain evidence of maternal transmission of peanut allergy susceptibility to their offspring.
They also investigated the effect of exposure to peanut during pregnancy and lactation on the development of peanut allergy in offspring. Results of their work indicate that maternal peanut allergy is a risk factor for developing peanut allergy. It also appears that exposure to small amounts of peanut during pregnancy and lactation can reduce the risk of peanut allergy developing in the offspring of peanut-allergic mothers.
The mouse models used in the research have been specifically bred to have IgE-mediated allergy to peanut. The female mice were sensitised with peanut and subsequently mated with non-allergic male mice. In one part of the study, the female mice were fed a normal, peanut-free diet throughout pregnancy and lactation. Three to four weeks after weaning, at the age of 5 weeks, their offspring were challenged with 200 mg/mouse of ground peanut.
Another part of the study was designed to test the impact of low exposure to peanut during pregnancy and lactation. For this, a group of peanut allergic pregnant female mice was divided into two. One group received feed containing low levels of peanut (10mg/mouse) for 5 weeks while the mice in the second group were given feed containing no peanut for the same period. At the age of 5 weeks, the offspring from both groups were given an oral challenge with peanut. The 5-week-old offspring from these groups were subsequently challenged with peanut intragastrically. In another subset of the experiment, offspring of both of these groups were sensitized with peanut intragastrically for 6 weeks, and serum peanut-specific antibodies were determined.
Results showed that offspring from the peanut allergic mice had anaphylactic allergic reactions on their first exposure to peanut. In the second experiment, offspring of the mice that had been fed peanut showed significantly reduced first-exposure reactions to peanut compared to the offspring of those mice that were fed a peanut-free diet. In the third component of the research, the offspring of mice fed with peanut showed a reduction in peanut-specific IgE to the active peanut sensitisation.
Reference: Lopez-Exposito et al.2009. Journal of Allergy and Clinical Immunology Vol 124(5) pp 1039-1046
Cashew reactions more severe than peanut
The incidence of cashew allergy has been reported to be increasing, and cashew allergy appears to invoke more severe reactions. Researchers in Texas have recently published a paper describing the clinical characteristics of cashew allergic patients attending the Texas Children’s Hospital, compared to those allergic to peanut.
Patients were identified through a retrospective chart review, and a phone survey was conducted to identify the clinical characteristics of cashew allergic patients in comparison to peanut allergic patients. Patients were selected based on documentation or history of clinical allergy by questionnaire and chart review and positive specific IgE (>0.35 kU/L). Age at exposure, quantitative serum IgE, clinical presentation characteristics, and atopic history were recorded.
Results showed that patients with cashew allergy were more likely to experience anaphylaxis and less likely to have atopic dermatitis than patients with peanut allergy. Anaphylaxis was present in 50% of cashew and 25% of peanut allergic patients attending the hospital. Half of the cashew-allergic patients presented at the clinic with respiratory symptoms. Rates of asthma, allergic rhinitis, and concomitant food allergy were similar in both groups.
The authors concluded that cashew allergy was more likely to result in severe reactions such as anaphylaxis than peanut allergy. Because of this, cashew-allergic patients and their parents should be educated on the correct use of the epinephrine auto-injector and strictly avoid exposure to all tree nuts.
Reference: Grigg et al. 2009. Pediatric Asthma, Allergy & Immunology. Doi:10.1089/pai.2009.0017.
Another survey shows food allergies on the rise
Researchers from the U.S. Centers for Disease Control and Prevention have used information from four different national data sources, including reports from parents and healthcare centres, to assess the current rate of food allergies in the United States.
Results indicate an 18 percent increase in the incidence of food allergy between 1997 and 2007, with parents of almost 4 percent of U.S. children (under 18 years of age) reporting a food or digestive allergy in their child.
Data collected between 1993 and 2006 from health-care providers indicated that the number of children being treated for food allergies had tripled. This anomaly in health-care provider versus parental reporting was possibly due to increased accuracy in coding the medical event as food allergy.
Of interest, survey results showed that Hispanic children had the lowest overall prevalence of food allergy but had the greatest increases over time of parent-reported incidences of food allergy.
The data used in this study was collected in the 1997-2007 National Health Interview Survey, 2005-2006 National Health and Nutrition Examination Survey, 1993-2006 National Hospital Ambulatory Medical Care Survey and National Ambulatory Medical Care Survey, and 1998-2006 National Hospital Discharge Survey. From these studies, parent reports about food allergies, serum immunoglobulin E antibody levels for specific foods, ambulatory care visits, and hospitalizations were assessed.
Reference: Branum and Lukacs 2009 Pediatrics. Vol 124(6) pp 1549-55.