Early Life Origins of the Food Allergy Epidemic: Predictors of Persistent Peanut Allergy at Age 5 Years
试验速览
- 阶段
- 不适用
- 状态
- Enrolling By Invitation
- 入组人数
- 200
- 主要终点
- Clinical tolerance to peanut (passing a peanut challenge and eating peanut regularly)
研究概览
简要总结
The purpose of this study is to determine if avoidance of peanut by children with positive allergy testing to peanut in the first 5 years of life increases the likelihood of developing a persistent peanut allergy by age 5 years. To answer this question, the investigators need to determine which children with positive allergy testing to peanut have reactions after eating peanut (allergic to peanut) and which are able to tolerate eating peanut (not allergic).
The investigators plan to conduct double-blind placebo-controlled peanut challenges (gold standard for peanut allergy diagnosis) for CHILD study (http://www.canadianchildstudy.ca) participants who had positive skin prick testing to peanut at ages 1, 3 or 5 years (in other words, children who are sensitized to peanut, but may or may not be allergic to peanut) and who are avoiding peanut without ever having had a reaction or whose history suggests that they may have outgrown a known peanut allergy. These challenges will not change a child's ability to tolerate peanut, but will determine if children who are avoiding peanut are allergic to peanut (and need to continue avoiding peanut) or clinically tolerant to peanut (and may continue to eat peanut after passing the challenge).
详细描述
Introduction:
Food allergy has reached epidemic levels in Canada and peanut allergy is the most prevalent and one of the more persistent food allergies among Canadian children and adults. Avoidance or later introduction of peanut has been proposed as a possible cause of the increased rates of peanut sensitization and allergy. Although delaying the introduction of peanut into children's diets is no longer recommended, many parents continue to worry about introducing peanut and some will not introduce peanut into their child's diet without a negative skin prick test to peanut. However, some children who have never had a reaction to peanut can eat and tolerate peanut despite being sensitized (having a positive skin prick test) to peanut.
The purpose of this study is to determine if avoidance of peanut by children with positive skin prick testing to peanut in the first 5 years of life increases the likelihood of developing a persistent peanut allergy by age 5 years. To answer this question, the investigators need to determine which children with positive skin prick testing to peanut have reactions after eating peanut (allergic to peanut) and which are able to tolerate eating peanut (not allergic).
Specific Objectives:
- To conduct double-blind placebo-controlled peanut challenges among 5-year-old children who are sensitized to and avoiding peanut, to determine if they are allergic to peanut (and need to continue avoiding peanut) or clinically tolerant to peanut (and may continue to eat peanut after passing the challenge)
- To determine the relative risk of developing peanut allergy among peanut-sensitized children who have been eating versus avoiding peanut.
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Prospective
入排标准
- 年龄范围
- 4 Years 至 10 Years（Child）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Challenge Inclusion Criteria:
- •CHILD study participants will be eligible for challenge if they
- •Have completed their 5-year-old CHILD Study visit
- •Are or have been sensitized to peanut i.e. have had a positive skin prick test (wheal diameter at least 2 mm greater than the negative control) and/or allergen-specific IgE level (>0.35 kU/L) to peanut at their 1-, 3- and/or 5-year-old CHILD study visit
- •Are not eating peanut. Children who eat less than 8-10 g of peanut per month or who eat only foods that 'may contain' traces of peanut will still be eligible for inclusion.
排除标准
- •CHILD study participants will be ineligible for challenge if
- •They have never had a positive skin prick test or allergen-specific IgE level to peanut
- •They are eating 8-10 g of peanut at least once per month, despite having had a positive skin prick test or allergen-specific IgE level to peanut
- •Their family has declined to participate
- •They have a peanut skin prick test wheal size >8mm and/or a peanut-specific IgE >15 kU/L and a history suggestive of an IgE-mediated allergic reaction to peanut.
- •They have a history of anaphylaxis to peanut or a challenge-proven diagnosis of peanut allergy within the past 1-2 years.
- •They have uncontrolled asthma or any other contraindication to performing a DBPC food challenge on the day of challenge. These children may be rescheduled if their asthma control improves.
- •Blood Draw Inclusion Criteria:
- •CHILD study participants will be eligible for blood draw if they
- •Have completed their 5-year-old CHILD Study visit
- •Are or have been sensitized to peanut i.e. have had a positive skin prick test (wheal diameter at least 2 mm greater than the negative control) and/or allergen-specific IgE level (>0.35 kU/L) to peanut at their 1-, 3- and/or 5-year-old CHILD study visit
- •Blood Draw Exclusion Criteria:
- •CHILD study participants will be ineligible for blood draw if
- •They have never had a positive skin prick test or allergen-specific IgE level to peanut
- •Their family has declined to participate
- •Immunological analyses of the blood samples are underway now that the 2 sites participating in this portion of the study (University of Manitoba and University of British Columbia) have completed their challenges. Challenges were halted in the spring.
研究组 & 干预措施
Avoiding and possibly allergic to peanut
Challenge Group: Children with positive skin prick testing to peanut who are avoiding peanut will undergo a double-blind placebo-controlled peanut challenge (gold standard for peanut allergy diagnosis) if their allergy evaluation suggests that they have a good chance of not being allergic to peanut. Children who pass the challenge are not allergic to peanut. Children who react during the challenge are allergic to peanut and will continue to avoid peanut.
干预措施: Double-blind placebo-controlled peanut challenge (Procedure)
Not allergic to peanut
Comparison Group: Children with positive skin prick testing to peanut who are eating and tolerating peanut are not clinically allergic to peanut and may continue eating peanut.
结局指标
主要结局
Clinical tolerance to peanut (passing a peanut challenge and eating peanut regularly)
时间窗: Age 5 years
Clinical tolerance to peanut (passing a peanut challenge and eating peanut regularly)
次要结局
未报告次要终点
研究者
Elinor Simons
Dr. Elinor Simons, Assistant Professor
University of Manitoba