The National Health Interview Survey (NHIS) is a primary source of information on the health of the population of the United States.  The NHIS is a cross-sectional household interview survey that is fielded continuously throughout the year. For the 1990 survey, the sample plan included approximately 49,000 eligible households yielding a probability sample of about 127,000 persons.

A core questionnaire collected data on topics such as injuries, diseases, conditions, disability, limitation of activity, doctor visits, hospitalization, and demographic information such as housing, family composition, income, etc. The supplement questionnaire for the 1990 NHIS contains sections on HIV/AIDs knowledge and attitudes, assistive devices, family resources, health promotion and disease prevention, hearing, injury control and child health and safety, podiatry, and pregnancy and smoking.