Knowledge about AIDS and HIV in. the Local Incidence of AIDS

Transcription

1 Knowledge about AIDS and HIV in the US Adult Population: Influence of the Local Incidence of AIDS WINI;N i.w=.ffl Lida F. McCaig, MPH, Ann M. Hardy, DrPH, and Deborah M. Wuzn, PhD Introduction On the national and local levels, much effort in the control and prevention of human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS) has focused on educating both the general public and specific high-risk groups. It is important to evaluate these efforts periodically to determine if educational messages have reached their targets and to examine factors that influence knowledge levels. Evaluation of the national AIDS public information campaign has involved a variety of methods and data sources, including the National Health Interview Survey (NHIS) current health topic on AIDS Knowledge and Attitudes. AIDS incidence rates in a geographic area may affect the public's knowledge about AIDS and HIV infection for several reasons. For one thing, demographic variables (e.g., education) that are associated with different levels of knowledge may be distributed differently among low-, medium-, and high-incidence areas. For another, local educational efforts may have begun earlier or been more intense in areas of higher incidence. Moreover, persons in high-incidence areas may have a greater chance of knowing someone with AIDS and/or may perceive themselves to be at greater personal risk of developing AIDS, either ofwhich factor may increase their opportunity and desire to learn more about the disease. Finally, national polls have found that, as the distance from the major AIDS epicenters increases, the public perceives AIDS to be less threatening.' Thus, if knowledge of AIDS and HIV infection is affected by the incidence of AIDS in the area under study, this information should be incorporated into the planning of public information efforts. This study examined data from the 1988 NHIS AIDS Knowledge and Attitudes survey to determine how knowledge varied by demographic characteristics and among populations residing in areas with low, medium, and high annual incidence rates of AIDS. Because the NHIS is the only survey of AIDS knowledge that is based on a national probability sample, it provided a unique opportunity to evaluate knowledge of AIDS and HIV infection by incidence areas on a national level. Methods The NHIS, a cross-sectional sample survey of the US civilian, noninstitutionalized population, has been conducted annually since 1957 by the National Center for Health Statistics, one of the Centers for Disease Control (CDC).2 Each year, members of households across the country are interviewed in person by US Bureau of the Census personnel. The NHIS sample design is a multistage, stratified, probability sample of the US population.3 The first questionnaire about AIDS was included in the NHIS in The questionnaire was then revised, and data collection with the version of the AIDS survey described in this report began in The questionnaire, administered to one randomly selected adult aged 18 years At the time of the study the authors were with the Division of Health Interview Statistics, National Center for Health Statistics, in Hyattsville, Md. Requests for reprints should be sent to Linda F. McCaig, MPH, Health Statistician, Ambulatory Care Statistics Branch, Division of Health Care Statistics, National Center for Health Statistics, 6525 Belcrest Road, Room 950, Hyattsville, MD This paper was submitted to the journal October 10, 1990, and accepted with revisions May 6, American Journal of Public Health 1591

2 McCaig et al. or older in each family included in the NHIS sample, was designed primarily to estimate adults' knowledge about AIDS, HIV transmission, and prevention of HIV infection. In the questionnaire, the term "AIDS virus" was used instead of "HIV" because it was believed to be more readily understood. In this report, however, "AIDS" refers to the disease, "HIV" to the virus. Sample persons were classified by the annual incidence rate of AIDS in their county of residence. The annual incidence rates ofaids in census-defined metropolitan statistical areas (MSAs) with or more population for the period April 1988 to March 1989 was ascertained from the HIV/AIDS Surveillance Report published by CDC.4 The 94 MSAs listed in the CDC report were then compared with the counties included in the NI{S sample.5 The 6 MSAs not part of the NHIS sample were excluded, and the remaining 88 MSAswere ranked according to incidence rate from lowest to highest. Three groups were then determined by two break points in the list where the rates in one area differed from those in the next higher area by 1.5% or more. Also considered in making these determinations was that each incidence area would have a sufficient sample size for analyses. The incidence areas were classified as low (fewer than 10 cases per population, 46 MSAs, range ), medium (10 to 27 cases per population, 35 MSAs, range ), or high (more than 27 cases per population, 7 MSAs, range ) İncidence rather than prevalence rates were used to classify counties because that was the measure available as reported by CDC. However, in 1988, ranking cities by prevalence or incidence rates would probably have yielded the same order. CDC provides annual AIDS incidence data only for MSAs with or more population to ensure the anonymity of persons with AIDS who reside in small cities or rural areas.4 Fortyone percent of the NHIS sample did not live in the MSAs listed in the CDC report; therefore, it was not possible to classify all counties in the NHIS sample as to their incidence of AIDS. In 1988, adults-or about 90% of eligible sample persons-responded to the AIDS questionnaire; of those, persons could be classified into an AIDS incidence area. This includes 58% of the NHIS sample eligible for the AIDS Knowledge and Attitudes survey and represented 59% of the US population aged 18 years and over. For results presented by AIDS incidence area, only the part of the sample with incidence assigned was used; for national estimates, the entire NHIS sample eligible for the AIDS Knowledge and Attitudes survey was used. Three scales reflecting AIDS knowledge were constructed: transmission knowledge, general knowledge, and misperception scores. The 1988 NHIS AIDS questionnaire contained three questions that were used in this report to assess knowledge about recognized modes of HIV transmission (i.e., sexual, perinatal, and parenteral) (Table 1). For each respondent, the number of correct responses to these three statements was summed to yield a transmission knowledge score; this score could range from 0 to 3, with higher scores indicating more knowledge. Seven statements were used to assess general AIDS knowledge. For each respondent, the number of correct responses to these seven statements was summed to produce a general knowledge score; this score could range from 0 to 7, with higher scores indicating more knowledge. Seven questionswere used to assess misperceptions about HIV transmission through casual contact. For each respondent, the number of incorrect responses was summed to produce a misperception score; this score could range from 0 to 7, with higher scores indicating more misperceptions about HIV transmission through casual contact. The demographic variables examined included age (18 to 49 years and 50 years or older), race ethnicity (White non- Hispanic, Black non-hispanic, and Hispanic), and education, given that knowledge differences within these categories have been previously reported from the NHIS current health topic on AIDS Knowledge and Attitudes6'7 and elsewhere.1,8-14 Data were also analyzed by marital status for males younger than 50 years old because most AIDS cases have occurred inyoung men.15 Single men 1592 American Journal of Public Health December 1991, Vol. 81, No. 12

3 AIDS Knowledge in US Population: Influence of Incidence included those who were divorced, separated, or never married. To make national estimates, estimates derived from the NHIS sample were weighted to take into account selection probability, nonresponse, and an adjustment to the current US population.3 Mean scores and proportions were generated with SAS software. Standard errors (SEs) and statistical differences between mean scores were calculated with SE- SUDAAN, which takes into account the complex sample design of the NHIS.16 For the comparison of two means, the standard error ofthe difference (SED) was used to calculate the 95% confidence interval around the difference. All the differences noted in the text were significant at the 0.05 level. Results Of the respondents who could be classified into an AIDS incidence area, 12% (n = 2049) resided in an area with a high annual incidence of AIDS, 50% (n = 8625) resided in a medium-incidence area, and 38% (n = 6603) resided in a lowincidence area. Thirty-seven percent of the persons who lived in a high-incidence area were 50 years of age or older compared with 32% and 34% in medium- and low-incidence areas, respectively. Blacks made up 25% of the study group who lived in a high-incidence area compared with 16% in both medium- and low-incidence areas. Eighteen percent of persons residing in a high-incidence area were Hispanic compared with 10% and 4% in mediumand low-incidence areas, respectively. Twenty-three percent of persons living in a high-incidence area had less than a high school education compared with 19% and 21% in medium- and low-incidence areas, respectively. Fifty-one percent of unmarried males who were younger than 50 years of age resided in a high-incidence area compared with 47% and 44% in medium- and low-incidence areas, respectively Ẇhen the estimated overall mean transmission knowledge, general knowledge, and estimated misperception scores for persons classified into the three incidence groupings were compared with estimated scores for persons in areas not classified, no differences were found. Transmission Knowledge Scores The estimated mean transmission knowledge score was 2.8 (SE =.01) out of a possible 3 for both the nation and each AIDS incidence grouping. Persons 50 years of age or older had a mean transmission knowledge score of 2.7 compared with 2.9 for those aged 18 to 49years (SED =.01). Those with less than a high school education had a lower mean score (2.6) than those who had 12 years of education (2.9, SED =.01) and those who had 12 or more years of school (2.9, SED =.01). No differences in scores were noted by AIDS incidence area. SEDs for mean transmission knowledge scores in subgroups within incidence groupings ranged from.03 to.06. General Knowledge Scores The estimated mean general knowledge score for the nation was 4.8 (SE =.02) out of a possible 7, and overall, scores were nearly identical in each incidence grouping (Table 2). However, for the nation and within each incidence grouping, differences were observed for age, race ethnicity, education, and marital status for males. By level of education, the racial/ ethnic differences remained except for Hispanicswith 12 or moreyears ofschool. Hispanics who lived in a high-incidence area had a higher mean general knowledge score (4.6) than those in areas of medium (4.3, SED =.10) or low (4.3, SED =.14) incidence. SEDs for mean general knowledge scores in subgroups within incidence groupings ranged from.04 to.14. Misperception Scores The estimated mean misperception score for the nation was 2.9 (SE =.03) out of a possible 7. Overall and within each incidence grouping, differences were observed for age, race ethnicity, education, and marital status for males (Table 3). The effect of race/ethnicity on misperception scores remained after controlling for education except for Hispanics with 12 years of school. Overall, persons who lived in a highincidence area had a higher mean misperception score (3.1) than those who lived in areas of medium (2.8, SED =.09) or low (2.8, SED =.09) incidence. Persons 50 years of age or older who lived in a highincidence area had a higher mean misperception score (3.6) than those in the same age group who lived in areas of medium (3.3, SED =.13) or low (3.3, SED =.13) incidence. This pattern was not observed in younger adults. Persons who had 12 years ofeducation and who lived in a highincidence area had a higher average score (3.3) than persons with the same number ofyears of education who lived in areas of medium (3.0, SED =.12) or low (2.9, SED =.08) incidence, but no trends were observed among those with more or with less education. Single men in a low-incidence area had a higher average misperception score (2.8) than single men in a mediumincidence area (2.5, SED =.14). Married men in a high-incidence area had a higher average misperception score (3.0) than married men in a low-incidence area (2.6, SED =.16). SEs for mean misperception scores in subgroups within incidence groupings ranged from.06 to.25. December 1991, Vol. 81, No. 12 American Journal of Public Health 1593

4 McCaig et al. To test whether scores for counties with a very high annual incidence rate of AIDS were in any way remarkable, the three MSAs with the highest incidence rates were compared with the rest of the classifiable counties. The mean transmission knowledge scores were identical (2.8). However, the mean general knowledge score for the three highest MSAs (4.5) was significantly lower than that for the remainder of the counties (4.7, SE =.04), while the mean misperception score for the three highest MSAs (3.3) was significantly higher than that for the other counties (2.8, SE =.11). Diwscsion An effective educational program is a crucial part of the public health response to AIDS. The information from the continuing NHIS AIDS Knowledge and Attitudes survey has been useful for guiding national educational efforts and for evaluating specific campaigns such as the CDC's "Understanding AIDS" brochure, which was mailed to every US household in spring Disease knowledge and risk perceptions in an area might be hypothesized to be either positively or negatively associated with disease incidence in a crosssectional survey such as the NHIS. Ignorance of disease risk factors and of preventive measures might lead to adoption or continuance ofbehaviors that place an individual at risk, which, in turn, results in high incidence rates for the disease. Alternatively, in areas where a disease is common, effective public health efforts to educate the population could lead to an increasing knowledge of the disease. Misperceptions about transmission might be exacerbated by the disease frequency in an area if they are fueled by the public's concern about the greater probability of coming in contact with infected persons in a high-incidence area. On the other hand, misperceptions may be lower in a highincidence area if public health education has been successful.18 This analysis of the 1988 NHIS AIDS Knowledge and Attitudes survey shows that knowledge about the major modes of HIV transmission (i.e., sexual, parenteral, and perinatal) was high in all demographic groups in the United States. Overall, the nation's general knowledge about AIDS and HIV infection was high, and misperceptions about the risk of transmitting the virus through casual contact were few. This confirms data from numerous national, state, and local studies.1,6,7,1214,19-22 Previous studies have identified older persons, Blacks, Hispanics, and those with fewer than 12 years of education as being less knowledgeable about AIDS,1,6,8-14 a finding also supported by our study. Our report further demonstrates that the demographic determinants (i.e., age, race ethnicity, education) of knowledge and the misperception scores were the same within each AIDS incidence area as they were nationally. Among persons living in a high incidence area for AIDS, higher misperception scores were noted overall and for several subgroups: persons 50 years of age or older, persons with 12 years of education, and married men. Some of these differences may be explained by the proportionately higher number of older persons, minorities, and persons with less than a high school educationwho resided in highincidence areas. However, the absolute differences in misperception scores among those living in areas of high, medium, or low AIDS incidence were modest compared with differences attributable to age, race ethnicity, and education. In addition, because of the large sample size of the NH[S, some differences that were statistically significant were in magnitude quite small and probably of little practical importance. We did note larger differences when we focused on areas of extremely high AIDS incidence; however, these differences may have been due more to the distribution of certain demographic characteristics than to incidence. An inadequate sample size prevented us from further stratifying the data. National public opinion surveys conducted between 1983 and 1986 also found that misperceptions about AIDS showed some geographical variation.1 Perhaps these differences lessened by 1988, when the NHIS data used in this report were collected. Our overall findings of no differences in transmission and general knowledge scores in areas that differed markedly in the annual incidence of AIDS is in contrast to a recent finding in a study of gay men, in which bar clientele in areas with high AIDS prevalence were more knowledgeable about AIDS than men in lowprevalence areas.18 Homosexual men are at especially high risk, and findings for them may not apply to other groups. The NHIS AIDS Knowledge and Attitudes survey does include a general question assessing whether respondents have engaged in any of various HIV risk behaviors; however, only 2% reported engaging in such behaviors, and this group was too small to analyze in this study. Because AIDS incidence data are not available for all US counties, we could not classify 41% of the NHIS sample. Therefore, the findings from this report may not apply directly to these areas. However, areas not included are disproportionately nonmetropolitan (57%) and presumably of low incidence. Approximately 25% of noncassiflable areas are in states with low incidence rates (fewer than 5 cases per population), even in metropolitan 1594 American Joumal of Public Health December 1991, Vol. 81, No. 12

5 AIDS Knowldge in US Population: Influence of Indden areas. In addition, general knowledge about AIDS in areas that were not classifiable did not differ from such knowledge in areas that could be classified; the latter included areas with a wide range of population densities and presumably a wide cross-section of the American public. The observation that AIDS transmission knowledge and general knowledge scores in this national survey are similar for various demographic groups in the United States, regardless of the incidence level of AIDS, suggests that the ability of educational messages to reach and be absorbed by individuals nationwide depends less on whether those individuals currently live in an area where the annual incidence of AIDS is high than it does on demographic and other variables. Our finding, which shows the influence of age, race, ethnicity, and education on knowledge and perceptions about AIDS in geographic areas throughout the United States that vary by threefold or more in annual AIDS incidence, reinforces the importance of new and continued efforts to improve knowledge among older persons, minorities, and the less educated in all parts of the country. O] Acknowledgments The authors would like to thank Steven L. Botman, MA, and Ronald W. Wilson, MA, for thoughtflly reviewing the manuscript. References 1. Blake SM, Arkin EB. A summary of national public opinion surveys on AIDS: 1983 through AIDS Information Monitor. Washington, DC: American Red Cross, Kovar MG, Poe GS. The National Health Interview Survey Design, , and Prcedw-es, Hyattsville, Md: National Center for Health Statistics, Vital and Health Statistics; 1985:1(18). 3. Massey JT. Design and Estimation for the National Health Intervew Suwvey, Hyattsville, Md: National Center for Health Statistics, Vital and Health Statistics; 1989:2(110). 4. Centers for Disease Control. HIVIAIDS SurveillUance Report. April 1989, US Department of Commerce, Bureau of the Census. PSU's included in current sample surveys. USGPO, Washington, DC: September Hardy AM, Dawson DA. AIDS Knowledge and Attitudes for December 1988: Provisional Datafrom the NationalHealth Inteniew Survy. Advance data from vital and health statistics; no Hyattsville, Md: National Center for Health Statistics; CentersforDisease Control. HIVepidemic and AIDS: trends in knowledge-united States, 1987 and MMWR 1989;38: DiClemente RJ, Boyer CB, Morales ES. Minorities and AIDS: knowledge, attitudes, and misconceptions among Black and Latino adolescents. Am J Public Health. 1988;78: St. Lawrence JS, Betts R. Comparison of the knowledge, attitudes, and AIDS-risk behavior of Black and White college students in the Southeastern United States. Presented at the Fifth International Conference on AIDS. Abstracts; 1989: Seltzer R, Smith RC. Racial differences and intraracial differences among Blacks in attitudes towards AIDS. AIDS Public PolicyJ. 1988;3: Sonenstein FL, Pleck JH, Ku LC. Sexual activity, condom use and AIDS awareness among adolescent males. Fam Plann Perspect. 1989;21: Sy FS, Freeze-McElwee Y, Garrison CZ, Jackson KL. Knowledge, perceived risk, and beliefs about AIDS among high school and college students in South Carolina. J SC Med Assoc. 1989; Kappel S, Vogt RL, Brozicevic M, Kutzko D. AIDS knowledge and attitudes among adults in Vermont. Public Health Rep. 1989;104: Keeter S, Bradford JB. Knowledge of AIDS and related behavior change among unmarried adults in a low-prevalence city. Am JPrev Med. 1988;4: Centers for Disease Control. AIDS and human immunodeficiency virus infection in the United States: 1988 update. MMWR 1988;38(Suppl. S-4): Shah BV. SESUDAAN. Standard Error Program for Computing Standardized Ratesfitom Sample Survey Data. Research Triangle Park, NC: Research Triangle Institute; Rosenberg M, Dawson DA, Cyndmon ML. An evaluation of the national mailout "Understanding AIDS." Presented at the annual meeting of the American Public Health Association; November 13-17, 1988; Boston, Mass. 18. St. Lawrence JS, Hood HV, Brasfield T, Kelly JA. Differences in gay men's AIDS risk knowledge and behavior patterns in high and low AIDS prevalence cities. Public Health Rep. 1989;104: McKusick L, Horstman W, Coates TJ. AIDS and sexual behavior reported by gay men in San Francisco.AmJPublic Health. 1985;75: Kinnick BC, Smart DW, Bell DA, Blank WR, Gray TR, Schober JL. An assessment of AIDS-related knowledge, attitudes, and behaviors among selected college and university students. AIDS Public Policy J. 1989;4: Goodman E, Cohall AT. Acquired immuno-deficiency syndrome and adolescents: knowledge, attitudes, beliefs, and behaviors in a New York City adolescent minority population. Pediat,ics. 1989;84: Beaman ML, Strader MK. STD patients' knowledge about AIDS and attitudes toward condom use. J Community Health Nuws. 1989;6: December 1991, Vol. 81, No. 12 American Journal of Public Health 1595