Effects of upper versus lower respiratory infections on the induction of atopic asthma.

与20-30年前相比，现在发达国家的哮喘更加普遍。在发展中国家，患哮喘的儿童要少得多，而且近年来哮喘的发病率似乎也没有出现同样的增长。发达国家的儿童倾向于较少的呼吸道感染，最近的研究表明，这可能是哮喘增加的部分原因。了解发达国家哮喘增加的原因可能会导致制定预防哮喘的策略。为了了解呼吸道感染在诱发哮喘中可能发挥的作用，有必要对婴儿从出生起就进行研究，记录每一次呼吸道感染并监测他们的饮食。在最近的一项大型研究中，我们表明，父母报告的普通感冒和胸部感染确实会影响6岁时有多少儿童患有哮喘。此外，在这项研究中，母乳喂养至少4个月似乎可以预防哮喘的发生。然而，我们无法证实该研究中的儿童实际感染了多少。我们目前正在研究236名婴儿，他们都有患哮喘和过敏的高风险。截至1998年11月底，这些婴儿中有163人已满一岁。在生命的第一年，这些婴儿总共有669例呼吸道感染，个别婴儿的感染在0到11例之间。我们现在计划监测这些儿童，直到他们5岁，届时我们将确定有多少儿童患有哮喘和过敏。通过这种方式，我们将能够确定早期呼吸道感染较多的儿童在5岁时是否更有可能患有哮喘和过敏。我们还将能够判断母乳喂养是否能够减少患哮喘和过敏的机会。

Asthma is more common now in developed countries than it was 20-30 years ago. Many fewer children have asthma in developing countries and there does not appear to have been the same increase in asthma in recent years. Children in developed countries tend to have fewer respiratory infections and recent studies suggest that this may be partly responsible for the increase in asthma. An understanding of why asthma has increased in developed countries may lead to strategies to prevent asthma. In order to understand the role that respiratory infections may play in the induction of asthma, it is necessary to study babies from birth, documenting each respiratory inflection and monitoring their diet. In a recent large study we have shown that parental reports of common colds and chest infections do influence how many children have asthma at age 6. Also in this study, breast feeding for at least 4 months seemed to be protective against developing asthma. However, we were not able to verify how many infections the children in that study actually had. We are currently studying a population of 236 infants, all of whom are at high risk of developing asthma and allergies. At the end on November 1998, 163 of these infants had reached one year of age. During the first year of life, these infants had a total of 669 respiratory infections, with individual babies having between 0 and 11 infections. We now plan to monitor these children until they turn 5, when we will determine how many have asthma and allergies. In this way we will be able to determine whether children who have more respiratory infections early in life are more or less likely to have asthma and allergies at 5 years of age. We will also be able to tell whether breast-feeding is able to decrease the chance of developing asthma and allergies.