American Journal of Epidemiology刊登的一项最新研究发现，婴儿在6个月大之前使用抗生素，儿童期罹患哮喘危险会增加70%以上。
美国耶鲁大学科学家发现，如果婴儿在生命头几个月就接受一个疗程的抗生素治疗，那么日后罹患不可治愈型哮喘的危险会增加40%。为了治疗难治感染而接受第二个疗程抗生素治疗的婴儿，其哮喘危险会增加70%。
科学家表示，即便哮喘家族病等因素可以解释一些孩子罹患哮喘的原因，但是，小儿使用抗生素与儿童期哮喘之间依然存在密切关联。儿童期，男孩哮喘发病率比女孩更高，但是青春期时，女孩哮喘几率比男孩高。多项研究暗示，小儿过早使用抗生素是导致哮喘的关键因素之一。
很多小儿因为胸腔感染而接受抗生素。但是一些专家认为，导致日后哮喘危险增加的正是小时候的胸部感染，而非抗生素惹的祸。另一些专家认为，哮喘家族病史更可能是增加哮喘危险的病因。
耶鲁大学科学家调查了1400名儿童，目的是为了探明小儿使用抗生素是否会导致6岁前哮喘危险升高。新研究特别关注6个月大之前因为非胸腔感染而使用过抗生素的孩子。研究还涵盖一些无哮喘家族病史的孩子。
耶鲁大学科学家发现，半岁前使用抗生素会扰乱小家伙肠道保护性微生物的平衡，婴儿肠道的这些微生物具有防病作用。早期保护性微生物(特别是肠道中的微生物)对于儿童期成熟而平衡的免疫系统非常必要。而抗生素(特别是广谱抗生素)的使用，会改变孩子肠道菌群，进而导致免疫系统失衡，抗过敏反应能力削弱。
新研究负责人卡利·里斯尼斯表示，新研究结果提醒广大医生，婴儿(特别是对于那些低危险患儿)应尽量避免使用抗生素。
Antibiotic Exposure by 6 Months and Asthma and Allergy at 6 Years: Findings in a Cohort of 1,401 US Children
Abstract
Many studies have reported that antibiotic use may be associated with increased risk of childhood asthma. Respiratory tract infections in small children may be difficult to distinguish from early symptoms of asthma, and studies may have been confounded by “protopathic” bias, where antibiotics are used to treat early symptoms of asthma. These analyses of a cohort including 1,401 US children assess the association between antibiotic use within the first 6 months of life and asthma and allergy at 6 years of age between 2003 and 2007. Antibiotic exposure was associated with increased risk of asthma (adjusted odds ratio = 1.52, 95% confidence interval (CI): 1.07, 2.16). The odds ratio if asthma was first diagnosed after 3 years of age was 1.66 (95% CI: 0.99, 2.79) and, in children with no history of lower respiratory infection in the first year of life, the odds ratio was 1.66 (95% CI: 1.12, 3.46). The adverse effect of antibiotics was particularly strong in children with no family history of asthma (odds ratio = 1.89, 95% CI: 1.00, 3.58) (Pinteraction = 0.03). The odds ratio for a positive allergy blood or skin test was 1.59 (95% CI: 1.10, 2.28). The results show that early antibiotic use was associated with asthma and allergy at 6 years of age, and that protopathic bias was unlikely to account for the main findings.
