Pediatric Pulmonology 47:211–219 (2012) Original Articles Fifty Years of Pediatric Asthma in Developed Countries: How Reliable Are the Basic Data Sources? Jasneek Chawla, MD, MRCPC, 1 Michael Seear, MD, FRCPC, 1 * Tingting Zhang, MSc, 2 Anne Smith, MSc, 2 and Bruce Carleton, Pharm D 2 Summary. Given the difficulties in diagnosing, or even defining, asthma in children, claims of a pediatric asthma epidemic in Canada and other developed countries are accepted with sur- prisingly little critical examination. We reviewed a broad range of data sources to understand how the epidemic evolved during the last 50 years and also to assess the reliability of the conclusions drawn from that data. We obtained Canadian National and Provincial data from Statistics Canada National Population Health Survey, and the British Columbia Ministry of Health respiratory database. International data were obtained by extensive review of pediatric asthma epidemiological surveys published during the last 50 years. In many developed coun- tries, there have been three separate epidemics involving different aspects of pediatric asthma during the last 50 years: a double peaked mortality epidemic (1960s and 1980s), a hospital admission epidemic (peaked around 1990) and a steadily growing epidemic of children who report asthmatic symptoms on questionnaires. Canadian pediatric rates for asthma mortality (1–2/million/year) and hospital admission (1–2/thousand/year) are low and have fallen for the last 20 years. Rates based on questionnaire studies are high (10–15/hundred) and rose steadi- ly over the same period. Objective reductions in asthma deaths and hospital admission likely reflect improved education and treatment programmes. Current claims of an epidemic based largely on subjective self-reported symptoms require more careful analysis. The possibil- ity that symptom misperception, disease fashions, and poor recall, may be part of the explana- tion for the current high levels of self-reported symptoms deserves more attention. Pediatr Pulmonol. 2012; 47:211–219. ß 2011 Wiley Periodicals, Inc. Key words: asthma epidemic; respiratory questionnaires; diagnostic error; children. Funding source: none reported. 1 Division of Respiratory Medicine, British Columbia’s Children’s Hospi- tal, Vancouver, British Columbia, Canada. 2 Pharmaceutical Outcomes Programme, British Columbia’s Children’s Hospital, Vancouver, British Columbia, Canada. Authors’ contributions: Dr. Chawla, Dr. Ms. Zhang, and Dr. Ms. Smith retrieved epidemiological data from a wide range of sources. They, along with Dr. Seear and Dr. Carleton, were then equally responsible for data analysis, manuscript preparation, and final approval. Ethical approval: The study is based on the analysis of data obtained from national health databases and studies published in medical journals, all of which followed conventional rules of patient confidentiality. No individuals were identifiable, no human subjects were directly involved and no treatments were given. Given these study conditions, our Institu- tional and University research ethics committees waived the need for ethical approval. The University of British Columbia Behavioural Research Ethics Board gave us permission to conduct analyses using BC data. Funding source: No research funding was used. Small costs were covered by the Divisional operating budget. None of the five authors had personal or financial conflicts of interest with any aspect of the research study. *Correspondence to: Michael Seear, MD, FRCPC, Room 1C 31, BC’s Children’s Hospital, 4480 Oak Street, Vancouver, BC, Canada V6H 3V4. E-mail: mseear@cw.bc.ca Received 30 March 2011; Accepted 13 July 2011. DOI 10.1002/ppul.21537 Published online 8 September 2011 in Wiley Online Library (wileyonlinelibrary.com). ß 2011 Wiley Periodicals, Inc.