Original article Dietary intake in sensitized children with recurrent wheeze and healthy controls: a nested case–control study The rapid increase in the prevalence of asthma and atopic disease is likely because of changes in lifestyle and/or in the environment. Amongst other factors, nutrition may have played a role. Two hypotheses have been put forward regarding different aspects of diet(1): (1) reduc- tion in dietary antioxidants (vitamin A, C and E) and/or antioxidant cofactors (selenium, copper and zinc) conse- quent to reduction in intake of fresh fruit and vegetables and an increase in convenience foods; (2) shift in fatty acid intake from omega-3 to omega-6 polyunsaturated fats because of an increase in margarine consumption and decline in animal fat consumption (2, 3). We aimed to investigate whether there are any differ- ences in dietary macro- and micro-nutrient intake between sensitized children with wheeze and nonsensi- tized asymptomatic children. We used a case–control study nested within the context of a prospective birth cohort, which allowed us to control for a number of risk factors, which have previously been associated with asthma and sensitization (parental sensitisation status and history of allergic disease, indoor allergen exposure, pet exposure, gender). Methods Study population Within an unselected population-based birth cohort study (Man- chester Asthma and Allergy Study), we carried out a nested case– control study comparing dietary intake of wheezy sensitized and nonwheezy nonsensitized children. The cohort is described in detail elsewhere (4, 5). Participants were recruited prenatally, and attended review clinic at age 3 years (±4 weeks). A standard respiratory questionnaire was interviewer- administered to collect the information on symptoms. Allergic sensitization (mite, cat, dog, grasses, milk and egg) was ascertained by skin prick testing; sensitization was defined as wheal at least 3 mm greater than the negative control. Indoor allergen levels were measured in dust samples collected at birth. Following the 3-year follow-up, parents were invited to enter their children into the case– control study. Based on the follow-up data, cases were defined using the following criteria: • Sensitized (skin test positive to at least one allergen). • Recurrent wheeze (at least three parentally-reported wheezy episodes). Cases were matched with control children (skin test negative, no history of wheeze) according to gender, month of birth, Background: The rising prevalence of asthma and allergic disease remains unexplained. Several risk factors have been implicated including diet, in par- ticular poly-unsaturated fats and antioxidant intake. Methods: A nested case–control study comparing the dietary intake of sensitized children with recurrent wheeze (age 3–5 years) and nonsensitized children who had never wheezed was carried out within an unselected population-based cohort. Cases and controls were matched for age, sex, parental atopy, indoor allergen exposure and pet ownership. Dietary intake was assessed using a val- idated semi-quantitative food frequency questionnaire and nutrient analysis program. Results: Thirty-seven case–control pairs (23 male, mean age 4.4 years) partici- pated. Daily total polyunsaturated fat intake was significantly higher in sensi- tized wheezers (g/day, geometric mean, 95% confidence intervals: 7.1, 6.4–7.9) compared with nonsensitized nonwheezy children (5.6, 5.0–6.3, P ¼ 0.003). Daily omega-3 and omega-6 fat intakes were not significantly different between the two groups. No significant differences were found in intake of any anti- oxidant or antioxidant cofactors between the groups. Conclusions: Young sensitized wheezy children had a significantly higher total polyunsaturated fat intake compared with nonsensitized nonwheezy children. However, we were unable to distinguish a significant difference in specific poly- unsaturated fat intakes. Otherwise the children in both groups had a very similar nutritional intake. C. S. Murray, B. Simpson, G. Kerry, A. Woodcock A. Custovic North West Lung Centre, Wythenshawe Hospital, Manchester, UK Key words: poly-unsaturated fat; antioxidant; sensitization; wheeze; childhood Clare S. Murray, MD MRCPCH North West Lung Centre Wythenshawe Hospital Manchester M23 9LT, UK Accepted for publication 11 May 2005 Allergy 2006: 61: 438–442 Copyright Ó Blackwell Munksgaard 2005 ALLERGY DOI: 10.1111/j.1398-9995.2005.00927.x 438