DIFFERENCES BETWEEN RESPONDENTS AND NONRESPONDENTS IN A MULTICENTER COMMUNITY-BASED STUDY VARY BY GENDER AND ETHNICITY

This study provides data on differences between respondents and nonres pondents by gender and ethnicity in a multicenter community-based stud y that is rarely collected and that may be useful for estimating bias in prevalence estimates in other studies. Demographic, general health, and cardiovascular risk factors were examined in black and white resp ondents and nonrespondents to the Atherosclerosis Risk in Communities (ARIC) Study, a prospective study investigating cardiovascular risk fa ctors in approximately 16,000 adults that was initiated in 1986 in fou r U.S. communities. In one of the communities (Jackson, MS) black part icipants were recruited exclusively; in another (Forsyth County, NC) 1 2% of the eligible sample were black, whereas the samples in Washingto n County, MD and the northwestern suburbs of Minneapolis, MN were almo st all white. Demographic and health characteristics were collected du ring a home interview. Subjects who subsequently agreed to complete a clinical examination were defined as respondents, while eligible parti cipants who only took part in the home interview were considered to be nonrespondents. Approxmately 75% of age-eligible individals (45-64 ye ars) in each community completed the home interview. In three of the c ommunities 86-88% of those who took part in the home interview also co mpleted the clinic examination, whereas only 63% did so in Jackson. Am ong white participants, response rates were similar in men and women a nd between communities. Among black participants, the response rates w ere considerably lower, particularly in men. White male respondents re ported a higher socioeconomic status, better general health and a lowe r prevalence of cardiovascular disease and associated risk factors tha n white male nonrespondents. The difference between white respondents and nonrespondents were greater for men than women despite similar res ponse rates. Among black participants, respondent/nonrespondent differ ences were usually of smaller magnitude or absent, particularly in wom en. General health status and recent hospitalization rates were almost identical in black respondents and nonrespondents. Low response rates can bias estimates of prevalence in community-based studies although differences between respondents and nonrespondents tend to exaggerate real differences beween respondents and the eligible population sample d. For example, among white males 25% of respondents and 44% of nonres pondents were current smokers, yet the estimated community prevalence of smoking was 31%. In conclusion, differences observed between respon dents and nonrespondents were in the expected direction, but were grea ter for men than women and for whites than blacks. Copyright (C) 1996 Elsevier Science Inc.