Two times epidemiological investigation were made to acquire the rules and characters of the incidence and morbidity of rickets and the epidemical factors of rickets in spring and autumn 1987 in Dali county.

• 为了解大荔县婴幼儿佝偻病发、患病规律及有关的流行因素,于1987年春、秋进行了两次流行病学调查。