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Facts on prevalence and mortality in asthma

There is strong evidence that asthma is a heritable disease. Studies in the prevalence of asthma of parents and children indicate that offspring of asthma patients are at higher risk compared to healthy individuals. Numerous population-based studies of twins have also demonstrated that concordance rates for asthma are clearly higher in homozygotic compared to dizygotic twins. In these studies genetic factors account for about 35 to 70% of the estimated risk.

Prevalence studies indicate that there has been a substantial increase comparing data documented in the 1980s and 1990s in children and adults. In children prevalence varies between 0 and 30% depending on the population studied. In adults data are more controversial. Prevalence rates range between 0 and 20%. Especially in elderly persons asthma seems to be underdiagnosed although some studies indicate that symptoms are equally present as in younger adults or children.

Mortality data on asthma are difficult to obtain and to interpret. Especially in older subjects cause of death may be miscoded due to the higher prevalence of COPD in this age group. Although based on a small number most reliable data can be achieved from the 5 to 34 year age group. Mortality rates (per 100,000) in persons aged 5 to 34 years range between 0.12 in Sweden and 0.86 in Australia. The ratio of mortality rate compared to prevalence of asthma may indicate possible shortages in the management of asthma in comparison of different populations.

Literature

Beasley CRW, Pearce NE, Crane J. Worldwide trends in asthma mortality during the twentieth century. In: Sheffer AL (ed.). Fatal asthma . 1998. Marcel Dekker: New York: 13-29

Enright PL, McClelland RL, Newman AB, Gottlieb DJ, Lebowitz MD. Underdiagnosis and undertre

The International Study of Asthma and Allergies in Childhood (ISAAC) Steering Committee. Worldwide variations in the prevalence of asthma symptoms: the International Study of Asthma and Allergies in Childhood (ISAAC). 1998 (b). Eur Resp J ; 12 (2): 315-335

O'Byrne P. GINA Executive Commitee. Global strategy for asthma management and prevention. 2004. National Institutes of Health. Publication No 02-3659

Wiesch DG, Meyers DA, Bleecker ER. Genetics of asthma. 1999. J Allergy Clin Immunol ; 104: 895-901

Prevalence of asthma symptoms in children (13-14yrs.)

Adapted from: The International Study of Asthma and Allergies in Childhood (ISAAC) Steering Committee. Worldwide variations in the prevalence of asthma symptoms: the International Study of Asthma and Allergies in Childhood (ISAAC). 1998. European Respiratory Journal; 12 (2): 315-335