A study of the Dutch Twin Registry examined both enironmental and genetic risk factors in susceptibility to asthma, eczema, and rhinitis in a large group of children.

• 一项研究荷兰双胞胎登记册的调查显示环境和遗传有害因素都会增加大量儿童对哮喘、湿疹和鼻炎的易感性。