C Gant

David Hide Asthma and Allergy Research Centre, Ньюпорт, England, United Kingdom

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Publications (12)86.36 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Correct diagnosis of food hypersensitivity (FHS) is important to ensure appropriate patient care and to accurately establish the population prevalence and incidence. Food challenges play a very important role in the diagnosis of FHS, but it is unclear when open food challenges (OFCs) opposed to double-blind placebo-controlled food challenges (DBPCFCs) should be used. This study investigated the use of OFCs and DBPCFCs when diagnosing FHS. Children with a reported history of FHS or with sensitization to a food without known previous consumption were invited to undergo food challenges. Children of consenting parents underwent an OFC and those with a positive OFC were approached to undergo a DBPCFC. Food challenges were either performed as 1-day or 1-week challenges depending on sensitization status and clinical history. Forty-one children underwent both OFCs and DBPCFCs. The positive predictive values for 1-day and 1-week OFCs were 73% (8/11; 95% CI: 39-94%) and 57% (20/35; 95% CI: 39-74%) respectively. There was no evidence to indicate that the younger children were more likely to have a positive OFC confirmed by a DBPCFC compared to older children (Fisher's exact P = 0.53). In the 1-day challenges parents indicated a preference for OFC rather than DBPCFC. By contrast, in the 1-week challenge parents indicated a preference for DBPCFC (P = 0.0192). Open food challenge may be suitable for diagnosing immediate objective symptoms, whereas DBPCFC may be needed for the diagnosis of delayed and mainly subjective symptoms, irrespective of the child's age.
    Journal of Human Nutrition and Dietetics 01/2008; 20(6):565-79. · 1.97 Impact Factor
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    ABSTRACT: Early life allergen exposure may increase the risk of childhood allergy, but the protective effect of reduction in allergen exposure remains uncertain. To evaluate the effect of reduction in food and house dust mite (HDM) allergen exposure in infancy in preventing asthma and allergy. Infants, at higher risk because of family predisposition, were recruited prenatally and randomized to prophylactic (n = 58) and control (n = 62) groups. Prophylactic group infants were either breast-fed with mother on a low allergen diet or given an extensively hydrolyzed formula. Exposure to HDM was reduced by the use of an acaricide and mattress covers. The control group followed standard advice. Development of allergic diseases and sensitization to common allergens (atopy) was assessed blindly at ages 1, 2, 4, and 8 years in all 120 children. Repeated measurement analysis, adjusted for all relevant confounding variables, confirmed a preventive effect on asthma: adjusted odds ratio (OR), 0.24; 95% CI, 0.09-0.66; P = .005; atopic dermatitis, OR, 0.23; CI, 0.08-0.64; P = .005; rhinitis, OR, 0.42; CI, 0.19-0.92; P = .03; and atopy, OR, 0.13; CI, 0.05-0.32; P < .001. The protective effect was primarily observed in the subgroup of children with persistent disease (symptoms at all visits) and in those with evidence of allergic sensitization. Allergic diseases can be reduced, for at least the first 8 years of life, by combined food and HDM allergen avoidance in infancy. Strict food and HDM allergen avoidance should be considered for prevention of allergy in high-risk infants.
    Journal of Allergy and Clinical Immunology 03/2007; 119(2):307-13. · 12.05 Impact Factor
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    ABSTRACT: Maternal food intake during pregnancy may influence the development of food hypersensitivity (FHS) in the child. A food frequency questionnaire estimating the frequency with which some of the mains food allergens are consumed was designed and validated. Pregnant women were recruited at the ante-natal clinic of St. Mary's Hospital, Isle of Wight, UK. A food frequency questionnaire was developed and validated by comparing responses to information recorded in 7 days food diaries. The reliability of the food frequency questionnaire was evaluated by asking women to complete the questionnaire on two separate occasions at 30 and 36 weeks gestation. Fifty-seven women completed the validity study and 91 women completed the reliability study. For both validity and reliability, questions with dichotomous response categories showed the highest level of agreement. Frequency of intake of foods commonly "hidden" in foods produced the lowest validity and reliability scores. In the validity study responses to the food frequency questionnaire identically matched information recorded in the food diaries 80% of the time, on average. In the reliability study, responses were identical on both questionnaires 85% of the time on average. In this study a food frequency questionnaire estimating the frequency with which some of the main food allergens are consumed during pregnancy was designed and validated. This food frequency questionnaire could be used in future studies to assess the role of maternal food intake in the development of FHS in the infant.
    Journal of Human Nutrition and Dietetics 05/2006; 19(2):129-38. · 1.97 Impact Factor
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    ABSTRACT: Allergy to Brazil nut is a relatively common nut allergy and can be fatal. However, the evidence is lacking regarding the best approach to its diagnosis. We sought to determine the relative merits of history, skin prick testing, measurement of serum-specific IgE and challenge in the diagnosis of Brazil nut allergy. Fifty-six children and adults with a history of an allergic reaction to Brazil nut or evidence of sensitization were investigated by questionnaire (n=56), skin prick tests (SPTs) (n=53), measurement of serum-specific IgE to Brazil nut (n=54) and double-blind, placebo-controlled labial, and if necessary oral, challenges (n=19). Brazil nut allergy occurred in highly atopic individuals of any age with a strong family history of atopy. In 24 of 56 (43%), the history of an immediate reaction was sufficient to make a diagnosis with confidence and an oral challenge was considered unsafe. Of the 19 subjects undertaking the 'gold standard' test of a double-blind, placebo-controlled, food challenge, all six subjects with a SPT of at least 6 mm had a positive challenge and all three subjects with a SPT of 0 mm had a negative challenge. In the remaining 10 (53%) subjects, where SPT was between 1 and 5 mm and serum-specific IgE was less than 3.5 kU/L, an oral challenge was performed resulting in three positive and seven negative challenges. A combination of history, SPT and serum-specific IgE was adequate in achieving a diagnosis in the majority (77%) patients with suspected Brazil nut allergy. However, a doubtful history with SPT between 1 and 5 mm, or a serum-specific IgE less than 3.5 kU/L may require an oral challenge to help determine the risk of a Brazil nut allergic reaction.
    Clinical & Experimental Allergy 03/2006; 36(2):226-32. · 4.79 Impact Factor
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    ABSTRACT: To determine whether artificial food colourings and a preservative in the diet of 3 year old children in the general population influence hyperactive behaviour. A sample of 1873 children were screened in their fourth year for the presence of hyperactivity at baseline (HA), of whom 1246 had skin prick tests to identify atopy (AT). Children were selected to form the following groups: HA/AT, not-HA/AT, HA/not-AT, and not-HA/not-AT (n = 277). After baseline assessment, children were subjected to a diet eliminating artificial colourings and benzoate preservatives for one week; in the subsequent three week within subject double blind crossover study they received, in random order, periods of dietary challenge with a drink containing artificial colourings (20 mg daily) and sodium benzoate (45 mg daily) (active period), or a placebo mixture, supplementary to their diet. Behaviour was assessed by a tester blind to dietary status and by parents' ratings. There were significant reductions in hyperactive behaviour during the withdrawal phase. Furthermore, there were significantly greater increases in hyperactive behaviour during the active than the placebo period based on parental reports. These effects were not influenced by the presence or absence of hyperactivity, nor by the presence or absence of atopy. There were no significant differences detected based on objective testing in the clinic. There is a general adverse effect of artificial food colouring and benzoate preservatives on the behaviour of 3 year old children which is detectable by parents but not by a simple clinic assessment. Subgroups are not made more vulnerable to this effect by their prior levels of hyperactivity or by atopy.
    Archives of Disease in Childhood 07/2004; 89(6):506-11. · 3.05 Impact Factor
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    ABSTRACT: RationaleInfants born to families with a history of atopy are more at risk of developing allergic diseases than those born to non-atopic families. Genetic influences, particularly maternal factors play a key role. We have investigated whether infants born to atopic and non-atopic mothers differ in terms of weaning, feeding and immunization practices, family pet ownership and exposure to smoking.
    Journal of Allergy and Clinical Immunology - J ALLERG CLIN IMMUNOL. 01/2004; 113(2).
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    ABSTRACT: RationaleThe UK Department of Health advises that pregnant women who are atopic, or for whom the father or sibling of their unborn child has an atopic disease may wish to avoid eating peanuts during pregnancy lactation. We investigated whether peanut avoidance in pregnancy is associated with a family history of atopy and other factors.
    Journal of Allergy and Clinical Immunology - J ALLERG CLIN IMMUNOL. 01/2004; 113(2).
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    ABSTRACT: In all, 1872 children were recruited as part of a larger study concerning food additives and behaviours in preschool children. This figure represented 70% of the whole population of 3 1/4 -year-old children resident on the Isle of Wight, UK. Parents completed an assessment concerning their perceptions of their child's behaviour. The results of this assessment were compared with scores on two validated parental questionnaires, the Weiss Werry Peters (WWP) hyperactivity scale and the Emotionality, Activity and Sociability Temperament Questionnaire (EAS), which were used to assess hyperactivity. The accuracy of parents in perceiving hyperactivity in their children was found to be around 50% if the child was hyperactive, and 89% if the child was not hyperactive. The implications of these findings for services are discussed. Frequencies of potential risk groups for future Attention Deficit Hyperactivity Disorder (ADHD) and Conduct Disorder were also suggested.
    Child Care Health and Development 06/2001; 27(3):241-50. · 1.70 Impact Factor
  • S H Arshad, C Gant
    Clinical & Experimental Allergy 02/2001; 31(1):5-7. · 4.79 Impact Factor
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    ABSTRACT: One hundred twenty children, identified before birth as being at high risk for atopy, were prenatally assigned to prophylactic or control groups. The infants in the prophylactic group either received breast milk from mothers on an exclusion diet or an extensively hydrolyzed formula. Their bedrooms and living rooms were treated repeatedly with an acaricide, and they used polyvinyl-covered mattresses with vented head areas. The infants in the control group were fed conventionally, and no environmental control was recommended. A significant advantage, first demonstrated at 1 year of age, persists for children in the prophylactic group. They have less of any allergy or eczema, but the reduced prevalence of asthma is no longer significant. Only three children in the prophylactic group had positive skin prick test results compared with 16 in the control group, suggesting a significant reduction in sensitization. A dual approach to allergen avoidance, focusing on foods and aeroallergens, appears to be beneficial in selected high-risk infants. Avoidance of potent allergens in early life increases the threshold for sensitization in these high-risk infants. Whether sensitization has been avoided or merely deferred has yet to be proved.
    Journal of Allergy and Clinical Immunology 06/1994; 93(5):842-6. · 12.05 Impact Factor
  • D W Hide, C Gant
    Clinical & Experimental Allergy 02/1994; 24(1):3-5. · 4.79 Impact Factor
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    ABSTRACT: There is much evidence that the development of allergic disorders may be related to early exposure of allergens, including those in breastmilk. We have tried to find out whether avoidance of food and inhaled allergens in infancy protects against the development of allergic disorders in high-risk infants. In a prenatally randomised, controlled study 120 infants with family history of atopy and high (greater than 0.5 kU/l) cord-blood concentrations of total IgE were allocated randomly to prophylactic and control groups. In the prophylactic group (n = 58), lactating mothers avoided allergenic foods (milk, egg, fish, and nuts) and avoided feeding their infants these foods and soya, wheat, and orange up to the age of 12 months; the infants' bedrooms and living rooms were treated with an acaricidal powder and foam every 3 months, and concentrations of Dermatophagoides pteronyssinus antigen(Der p l) in dust samples were measured by enzyme-linked immunosorbent assay. In the control group (n = 62), the diet of mothers and infants was unrestricted; no acaricidal treatment was done and Der p l concentrations were measured at birth and at 9 months. A paediatric allergy specialist unaware of group assignment examined the infants for allergic disorders at 10-12 months. Odds ratios were calculated by logistic regression analysis for various factors with control for other confounding variables. At 12 months, allergic disorders had developed in 25 (40%) control infants and in 8 (13%) of the prophylactic group (odds ratio 6.34, 95% confidence intervals 2.0-20.1). The prevalences at 12 months of asthma (4.13, 1.1-15.5) and eczema (3.6, 1.0-12.5) were also significantly greater in the control group. Parental smoking was a significant risk factor for total allergy at 12 months whether only one parent smoked (3.97, 1.2-13.6) or both parents smoked (4.72, 1.2-18.2).
    The Lancet 07/1992; 339(8808):1493-7. · 39.21 Impact Factor

Publication Stats

615 Citations
86.36 Total Impact Points

Institutions

  • 2006–2008
    • David Hide Asthma and Allergy Research Centre
      Ньюпорт, England, United Kingdom
  • 1994
    • Isle Of Wight NHS Trust
      Newport, Wales, United Kingdom