Do parents with an atopic family history adopt a ‘prudent’ lifestyle for their infant? (KOALA Study)

Abstract

SummaryBackground Atopic parents may adopt lifestyle characteristics that allegedly protect against atopic disease. If this is true, infants from atopic parents will be characterized by low-risk behaviour. Consequently, aetiologic studies on lifestyle factors and allergic disease in childhood may be biased by confounding by indication. Objective We explored whether the prevalence of 'prudent' lifestyle characteristics differs between atopic and non-atopic families. Methods Information about a family history of atopic manifestations and lifestyle characteristics was collected by repeated questionnaires in the Dutch KOALA Birth Cohort Study in 2469 infants from families with divergent lifestyle practices (conventional vs. alternative). Results In conventional lifestyle families, infants were less often exposed to environmental tobacco smoke when parents were atopic than when they were non-atopic (10.0% vs. 14.7%, P = 0.001). In alternative lifestyle families, exposure to smoking was very rare in both groups (1.7% vs. 2.6%). Pets were less often present in families with than without parental atopy (38.8% vs. 51.1%, P = 0.008 for conventional lifestyle families; 43.0% vs. 48.4%, P = 0.014 for alternative lifestyle families). Infants with atopic siblings had less often been vaccinated according to the standard scheme than infants with non-atopic siblings in conventional lifestyle families (76.6% vs. 85.5%, P o 0.001). In alternative lifestyle families, the difference was in the same direction but not statistically significant (30.1% vs. 40.5%, P = 0.143). Antibiotic use, breastfeeding and consumption of organic foods were unrelated to a family history of atopic manifestations. Conclusion Some 'prudent' lifestyle characteristics differed between atopic and non-atopic families, depending on whether atopic manifestations were present in parents or older siblings. This has important consequences for the validity in epidemiological studies on the aetiology of allergy in children. Confounding by indication because of a family history of atopic manifestations can best be controlled for by considering atopy in parents and siblings as separate confounders.

Early exposure to secondhand tobacco smoke and the development of allergic diseases in 4 year old children in Malmö, Sweden

“…Furthermore, in our study children with parents having an allergy were exposed to tobacco smoke to a lower degree than children with parents without allergies. Similar results have been shown in other studies [27]. …”

Predictors of Serum Total IgE in a Random Sample of 7–17 Year Old Children

“…A possible parental recall bias cannot be precluded as parents of atopic children may be more aware of factors that could have influenced the development of the disease [16]. Particularly, parents with confirmed or suspected atopic disease may change behaviour during pregnancy or in early life of the child to try to avoid passing on the disorder [17]. Parental predisposition in this study was defined as symptoms of asthma and/or hay fever in at least one parent when exposed to allergens.…”

Diphtheria, Pertussis, Poliomyelitis, Tetanus, and Haemophilus influenzae Type b Vaccinations and Risk of Eczema and Recurrent Wheeze in the First Year of Life: The KOALA Birth Cohort Study

“…We showed previously that some prudent lifestyle characteristics, among others, vaccinations, differed between atopic and nonatopic families, depending on whether atopic manifestations were present in parents or older siblings. 32 Therefore, we considered a parental and siblings' history of allergy as separate potential confounders in all of the analyses. "Infant's illness" was often a motive for alternative vaccination schedules but rarely for no vaccination, which also indicates that potential reverse causation is limited.…”