Report on the epidemiology, cause and risk factors of asthma

An article http://www.cmaj.ca/press/cmaj080612.pdf on the epidemiology, cause and risk factors of asthma is the first in a special report on asthma in CMAJ (Canadian Medical Association Journal) www.cmaj.ca designed for clinical practitioners. This review looks at risk factors for persistent asthma at different ages, including prenatal, infancy, childhood and adulthood.

Genetics, environment and host characteristics are risk factors for asthma. The significant increases in the incidence of asthma and geographic variation in prevalence rates support the idea that the environment plays a large role in the current asthma epidemic. As well, environmental triggers may affect asthma differently during various life stages and risk factors may change over time.

The report comes from the researchers conducting the Canadian Healthy Infant Longitudinal Development (CHILD) Study, a multicentre Canadian study involving 5000 pregnant women with the aim of better understanding the development of allergy and asthma in children.

"While many cross-sectional studies confirm a true increase in incidence and prevalence of asthma over the last 2-3 decades, much remains unknown as to the fundamental immune, genetic and environmental mechanisms underlying its development, and its increased expression especially in the developed world," write Dr. Malcolm Sears from McMaster University, Dr. Padmaja Subbarao, The Hospital for Sick Children (SickKids) and coauthors.

Reduction in risk of asthma, as well as true prevention, is a key but elusive goal of asthma management.