THE EFFECT OF GENETIC AND ENVIRONMENTAL FACTORS ON THE PREVALENCE OF ALLERGIC DISORDERS AT THE AGE OF TWO YEARS

Abstract

Purpose of the Study. To prospectively determine the effect of genetic and environmental factors upon the prevalence of allergic disorders noted by age 2 years. Study Population. With a relatively captive United Kingdom island population, 1174 children born over a 1-year period were evaluated at the age of 2 years. Methods. Information on family history, any diagnosis made by physicians over the 2 years, parental smoking, and presence of pets were obtained. Umbilical cord blood was obtained in 1106 cases for total IgE determination. Birth weight was used to analyze low birth weight as a factor. Socioeconomic information was also determined. Findings. Of the 1174 children, 275 had an allergic disorder. Rhinitis occurred in 3%, food intolerance in 5%, eczema in 11%, and asthma in 11%. Positive prick skin tests were noted in 5%. Risk factors determined by multivariate regression analysis were: For asthma—positive family history, male sex, low birth weight, maternal smoking and spring birth time. For eczema—family history only. For rhinitis—lower socioeconomic group and autumn birth time. For positive skin tests—male sex and low birth rate. Cord IgE values did not predict allergic disease at age 2 years. Reviewer9s Comments. This study of an English community helps to clarify important factors in the environment. The increased prevalence of asthma (11%) over rhinitis (3%) and the risk factors of maternal smoking, low birth weight, male sex, and spring versus autumn birth time favoring asthma is of particular interest. It would be interesting to see if the population develops a decreasing prevalence of asthma at age 2 years if the population can reduce the use of tobacco through education and public health efforts.