Late introduction of solids into infants' diets may increase the risk of food allergy development.

BACKGROUND: This study investigated risk factors associated with food allergy or food intolerance among school children in two Swedish towns. METHODS: Questionnaires were used to collect data on self-reported food allergy or intolerance (SRFA) in children aged 7-8 years from Mölndal in southwestern Sweden and Kiruna in northern Sweden. It included questions about specific food allergy or intolerance to cows' milk, hens' eggs, fish, peanuts, tree nuts, and cereals and also age of onset, type of symptoms and age of cessation. Information was also gathered on family allergy history, dietary habits, and certain lifestyle aspects. RESULTS: Of 1838 questionnaires distributed, 1029 were returned: 717/1354 (53%) from Mölndal and 312/484 (64%) from Kiruna. The cumulative incidence of SRFA was 19.6% with a significantly higher cumulative incidence in Kiruna (28.5%) than in Mölndal (15.7%), P < .001. Solids were introduced at a later age in Kiruna. Introduction of solids into a child's diet from the age of 7 months or later, and maternal history of allergic disease, were both risk factors associated with a higher risk of food allergy or intolerance. CONCLUSION: Late introduction of solids into an infant's diet may be one risk factor for developing food allergy or intolerance. Later introduction of solids in Kiruna may be one explanation for the higher cumulative incidence of SRFA in that region.

Pet-keeping in early life reduces the risk of allergy in a dose-dependent fashion.

OBJECTIVES: Several studies have indicated that early pet keeping could protect the infant from later allergy development. Here, we investigate if there is a dose-dependent association between cat- and dog-keeping during the first year of life and subsequent allergy development. METHODS: Two cohorts were investigated: a cross-sectional questionnaire-based study of 7- to 8-year-old children (N = 1029) from Mölndal and Kiruna, and a birth-cohort of children from the Västra Götaland county clinically evaluated for asthma and allergy by paediatricians up to the age of 8-9 years (N = 249). The cross-sectional study asked validated questions on asthma and allergy that had been used in two previous studies of children from the same areas. In the birth-cohort study, a diagnosis of asthma and allergy was based on predefined clinical criteria, and laboratory evaluation included blood eosinophils, skin-prick tests and specific immunoglobulin E analyses. Information on pets during first year of life was collected retrospectively in the Cross-Sectional Cohort and prospectively in the Birth Cohort. RESULTS: A dose-response association was seen, with less allergic manifestations (any of asthma, allergic rhinoconjunctivitis, or eczema) with increasing number of household cats and dogs during the first year of life. In the Cross-Sectional Cohort, allergy ever decreased from 49% in those with no pets to zero in those with five or more pets (P-value for trend 0.038), and from 32% to zero for allergy last year (P-value for trend 0.006). The same pattern was seen in Birth Cohort. Sensitization to animals, as well as pollens, also decreased with increasing number of animals in the household. CONCLUSION: The prevalence of allergic disease in children aged 7-9 years is reduced in a dose-dependent fashion with the number of household pets living with the child during their first year of life, suggesting a "mini-farm" effect, whereby cats and dogs protect against allergy development.

Allergic rhinoconjunctivitis continued to increase in Swedish children up to 2007, but asthma and eczema levelled off from 1991.

AIM: This study investigated whether allergies among schoolchildren increased in Sweden between 1979 and 2007 and whether the geographical differences observed in previous studies remained. METHODS: We collected questionnaire data on asthma, allergic rhinoconjunctivitis (ARC) and eczema in children aged seven to eight years from Mölndal, Gothenburg, in south-western Sweden and Kiruna in northern Sweden in 1979 (n = 4682), 1991 (n = 2481) and 2007 (n = 1029). The same regions and questions were used in all three studies, and extra questions on food allergy or intolerance were added in 2007. RESULTS: In 1979, 1991 and 2007, the total prevalence of asthma was 2.5%, 5.7% and 7.1%, ARC was 5.5%, 8.1% and 11.1% and eczema was 7.1%, 18.3% and 19.7%, respectively. Asthma prevalence remained higher in Kiruna, but no significant regional differences were seen for ARC and eczema. Almost 20% reported a history of food allergy or intolerance, with a higher prevalence in Kiruna. The allergy risk was reduced if both parents were born outside Sweden. CONCLUSION: The prevalence of ARC continued to increase between 1991 and 2007, but increases in asthma and eczema started to level off in 1991. Some geographical differences remained, but total allergy rates were similar in Kiruna and Mölndal in 2007.

Allergy in children in hand versus machine dishwashing.

BACKGROUND AND OBJECTIVE: The hygiene hypothesis stipulates that microbial exposure during early life induces immunologic tolerance via immune stimulation, and hence reduces the risk of allergy development. Several common lifestyle factors and household practices, such as dishwashing methods, may increase microbial exposure. The aim of this study was to investigate if such lifestyle factors are associated with allergy prevalence. METHODS: Questionnaire-based study of 1029 children aged 7 to 8 years from Kiruna, in the north of Sweden, and Mölndal, in the Gothenburg area on the southwest coast of Sweden. Questions on asthma, eczema, and rhinoconjunctivitis were taken from the International Study of Asthma and Allergies in Childhood questionnaire. RESULTS: Hand dishwashing was associated with a reduced risk of allergic disease development (multivariate analysis, odds ratio 0.57; 95% confidence interval: 0.37-0.85). The risk was further reduced in a dose-response pattern if the children were also served fermented food and if the family bought food directly from farms. CONCLUSIONS: In families who use hand dishwashing, allergic diseases in children are less common than in children from families who use machine dishwashing. We speculate that a less-efficient dishwashing method may induce tolerance via increased microbial exposure.