Race or ethnicity wasdefined by self-report as non-Hispanic white, non-Hispanic black, or Mexican-American. Persons who did not choose one of these categories were classified as “other” and were analyzed with the total population. The poverty-index ratio was calculated by dividing total family income by the poverty threshold index, adjusted for family size at year of interview. Residence in a county with a population equal to or greater than 1 million was defined as metropolitan residence. Residence in all other counties (including rural areas) was defined as nonmetropolitan. Data on years of education, marital status, occupation, and military service were analyzed for study participants 20 years of age or older. Participants were considered to have access to care if they indicated that they usually visited a particular clinic, health center, or physician's office when they were sick or for routine care. If a participant said that he or she usually saw one particular health professional or physician, he or she was categorized as having access to both a clinic and a physician.