Background Asthma is not the key focus of prevention strategies. A Healthy Lifestyle Index (HLI) was developed to examine the combined effect of modifiable lifestyle factors on asthma, rhinoconjunctivitis and eczema using data from the International Study of Asthma and Allergies in Childhood (ISAAC) phase III.
Methods Information on symptoms of asthma, rhinoconjunctivitis, eczema and several lifestyle factors was obtained from children aged 6–7 years through written questionnaires. The HLI combined five lifestyle factors: no parental smoking, child’s adherence to Mediterranean diet, child’s healthy body mass index, high physical activity and non-sedentary behaviour. The association between the HLI and risk of asthma, rhinoconjunctivitis and eczema was evaluated using multilevel mixed-effects logistic regression models.
Findings Data of 70 795 children from 37 centres in 19 countries were analysed. Each additional healthy lifestyle factor was associated with a reduced risk of current wheeze (OR 0.87, 95% CI 0.84 to 0.89), asthma ever (OR 0.89, 95% CI 0.87 to 0.92), current symptoms of rhinoconjunctivitis (OR 0.95, 95% CI 0.92 to 0.97) and current symptoms of eczema (OR 0.92, 95% CI 0.92 to 0.98). Theoretically, if associations were causal, a combination of four or five healthy lifestyle factors would result into a reduction up to 16% of asthma cases (ranging from 2.7% to 26.3 % according to region of the world).
Conclusions These findings should be interpreted with caution given the limitations to infer causality from cross-sectional observational data. Efficacy of interventions to improve multiple modifiable lifestyle factors to reduce the burden asthma and allergy in childhood should be assessed.
Statistics from Altmetric.com
Collaborators Steering committee—N Aït-Khaled* (Union Internationale Contre la Tuberculose et les Maladies Respiratoires, Paris, France); H R Anderson (Department of Public Health Sciences, St George’s Hospital Medical School, London, UK); M I Asher (Department of Paediatrics, Faculty of Medical and Health Sciences, University of Auckland, New Zealand); R Beasley* (Medical Research Institute of New Zealand, Wellington, New Zealand); B Björkstén* (Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden); B Brunekreef (Institute of Risk Assessment Science, Universiteit Utrecht, Netherlands); J Crane (Wellington Asthma Research Group, Wellington School of Medicine, New Zealand); P Ellwood (Department of Paediatrics, Faculty of Medical and Health Sciences, University of Auckland, New Zealand); L García-Marcos (Instituto de Salud Respiratoria, Universidad de Murcia, Spain); S Foliaki* (Centre for Public Health Research, Massey University, Wellington, New Zealand); U Keil* (Institut für Epidemiologie und Sozialmedizin, Universität Münster, Germany); C K W Lai* (Department of Medicine and Therapeutics, The Chinese University of Hong Kong, SAR China); J Mallol* (Department of Respiratory Medicine, University of Santiago de Chile, Chile); C F Robertson (Department of Respiratory Medicine, Royal Children’s Hospital, Parkville, Australia); E A Mitchell (Department of Paediatrics, Faculty of Medical and Health Sciences, University of Auckland, New Zealand); S Montefort* (Department of Medicine, University of Malta, Malta), J Odhiambo*† (Centre Respiratory Diseases Research Unit, Kenya Medical Research Institute, Nairobi, Kenya); N Pearce (Centre for Public Health Research, Massey University, Wellington, New Zealand); J Shah* (Jaslok Hospital and Research Centre, Mumbai, India); A W Stewart (Population Health, Faculty of Medical and Health Sciences, University of Auckland, New Zealand); D Strachan (Department of Public Health Sciences, St Georges Hospital Medical School, London, UK); E von Mutius (Dr von Haunerschen Kinderklinik de Universität München, Germany); S K Weiland† (Department of Epidemiology, University of Ulm, Germany); G Weinmayr (Institute of Epidemiology, University of Ulm, Germany); H Williams (Centre for Evidence Based Dermatology, Queen’s Medical Centre, University Hospital, Nottingham, UK); G Wong (Department of Paediatrics, Prince of Wales Hospital, Hong Kong, SAR China) (*Regional coordinators †deceased). ISAAC International Data Centre: M I Asher, T O Clayton†, P Ellwood, E A Mitchell (Department of Paediatrics, University of Auckland, New Zealand); and A W Stewart (School of Population Health, Faculty of Medical and Health Sciences, University of Auckland, New Zealand) (†deceased). ISAAC principal investigators: Belgium—J Weyler; Chile—L Amarales, P Aguilar; Colombia—A M Cepeda, G Aristizábal; Estonia—M-A Riikjärv; Hungary—G Zsigmond; Indonesia—C B Kartasasmita; Iran—M-R Masjedi; Japan—H Odajima; Lithuania—J Kudzyte; Mexico—B E Del-Río-Navarro, M Barragán-Meijueiro, R García-Almaraz, M Baeza-Bacab, S N González-Díaz, F J Linares-Zapién; New Zealand—M I Asher, P Pattemore; Oman—O Al-Rawas; Poland—G Lis, A Brêborowicz; Portugal—J E Rosado Pinto, J M Lopes dos Santos; Singapore—D Y T Goh; Spain—A López-Silvarrey Varela, I Carvajal-Urueña, R M Busquets, C González Díaz, L García-Marcos, G Garcia-Hernández, M M M Suárez-Varela; Syrian Arab Republic—Y Mohammad, S Mohammad; Thailand— M Trakultivakorn; Venezuela—O Aldrey.
Contributors EM and LGM conceived the study. EM and DS conducted the statistical analyses. EM, DS and LGM prepared the first draft. All other authors provided data, reviewed results and reviewed and contributed to the article.
Funding EM was funded by a Miguel Servet Grant Fellowship (MS14/00046) awarded by the Spanish Instituto de Salud Carlos III (ISCIII), Ministry of Economy and Competitiveness and Fondos FEDER.
Competing interests None declared.
Patient consent for publication Guardian consent obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.