الفهرس 
IntroductiionOnly 14 pages are availabe for public view
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Abstract
Data from epidemiological studies conducted in several countries worldwide have revealed that the prevalence of allergic conditions, including allergic rhinitis, asthma and eczema, have increased from the 1940s/50s to the 1990s. Although the increase of asthma prevalence may, in part, be explained by altered diagnostic criteria and increased awareness of the disease, both in the general population and among physicians. - The causes of the international increases in the prevalence of asthma are unclear and are currently a major focus for asthma epidemiology worldwide.. Thus, comparisons of asthma prevalence are increasingly being based on a simple comparison of symptom prevalence in a questionnaire survey in a large number of people (Phase I), followed by more intensive testing of factors related to asthma (e.g., BHR) and risk factors for asthma (skin prick test positivity, serum immunoglobulin E [IgE] and other exposures) in a sub-sample (Phase II). (Phase III) Reevaluation of the (Phase I) after 5-7 years in the International Study of Asthma and Allergies in Childhood (ISAAC). -The incidence and prevalence increase world wide from 8 % in 1986 to 23 % 2006. - The incidence and prevalence in the Middle East ranges from 5.5 % in Palestinian to 23 % in Saudi Arabia (2006). -The incidence and prevalence in Egypt increasing from 4.8 % in 1993 to 15 % in 2006. Sex. Male sex is a risk factor for asthma in children. Prior to the age of 14 Genetic. Asthma has a heritable component, but it is not simple Obesity. Obesity has also been shown to be a risk factor for asthma.. - Smoking. Tobacco smoking makes asthma more difficult to control, results in more frequent exacerbations and hospital admissions, and produces a more rapid decline in lung function and an increased risk of death. - Diet. - Artificial feed increase asthma. Low prevalence of asthma in diet, rich in fish and marine mammals.The increase of asthma prevalence has been subsequent to the fall in the consumption of animal fat and oily fish with high content of saturated fat and increase in the amount of margarine and vegetable oils, containing polyunsaturated fat, in the diet of Western countries. higher prevalence of and greater severity of symptoms in poorer children, but with no difference in prevalence of diagnosed asthma is at least in part due to discrepancies in access to health care. -Annual worldwide deaths from asthma have been estimated at 250,000 and mortality does not appear to correlate well with prevalence. -The costs of asthma depend on the individual patient’s level of control and the extent to which exacerbations are avoided. -Emergency treatment is more expensive than planned treatment. -Non-medical economic costs of asthma are substantial. -Guideline-determined asthma care can be cost effective. -Families can suffer from the financial burden of treating asthma. The “hygiene hypothesis” of asthma suggests that exposure to infections early in life influences the development of a child’s immune system along a “nonallergic” pathway, leading to a reduced risk of asthma and other allergic diseases