The tribulations of trials--intervention in communities

Implications of the results of community intervention trials

This paper examines the results of population-level interventions conducted in three settings: entire communities, worksites, and schools. Four major conclusions are discussed: (a) Directions for the next generation of community-based interventions include targeting multiple levels of influence; addressing social inequalities in disease risk; involving communities in program planning and implementation; incorporating approaches for "tailoring" interventions; and utilizing rigorous process evaluation. (b) In addition to randomized controlled trials, it is time to use the full range of research phases available, from hypothesis generation and methods development to dissemination research. (c) The public health research agenda may have contributed to observed secular trends by placing behavioral risk factors on the social and media agendas. (d) The magnitude of the results of community intervention trials must be judged according to their potential public health or population-level effects. Small changes at the individual level may result in large benefits at the population level.

Review of community-based research: assessing partnership approaches to improve public health

Community-based research in public health focuses on social, structural, and physical environmental inequities through active involvement of community members, organizational representatives, and researchers in all aspects of the research process. Partners contribute their expertise to enhance understanding of a given phenomenon and to integrate the knowledge gained with action to benefit the community involved. This review provides a synthesis of key principles of community-based research, examines its place within the context of different scientific paradigms, discusses rationales for its use, and explores major challenges and facilitating factors and their implications for conducting effective community-based research aimed at improving the public's health.

Community empowerment paradigm drift and the primary prevention of HIV/AIDS

Long discussed in the public health arena, the concept of empowerment has only recently entered the discourse on the primary prevention of HIV/AIDS in the United States. Despite its broad appeal, empowerment has not been systematically incorporated into theory-based interventions, which may reflect a lack of consensus on the meaning of empowerment, how to measure it, and the intervention strategies it implies. The purpose of this paper is to consider the relevance of empowerment to community interventions for persons at risk for HIV, particularly women. The origins of empowerment are reviewed; community empowerment as an intervention framework is described and its core assumptions defined. There is some evidence of the growing influence of empowerment and related concepts in recent HIV-related policy, research, and programs funded through the Centers for Disease Control and Prevention. However, adoption of an empowerment framework for HIV prevention will require further theory and measurement development, as well as changes in how public health researchers and practitioners work with the communities they serve.

Effects of the Heartbeat Wales programme over five years on behavioural risks for cardiovascular disease: quasi-experimental comparison of results from Wales and a matched reference area

OBJECTIVE

To assess the net 5 year effects of intervention of a community based demonstration project, the Heartbeat Wales programme, on modifiable behavioural risks for prevention of cardiovascular disease.

DESIGN AND SETTING

Quasi-experimental design comparing results from two independent cross sectional population surveys conducted in 1985 and 1990 in Wales and a matched reference area in north east England.

SUBJECTS

Random, stratified samples of people aged 18-64 years (18,538 in 1985 and 13,045 in 1990) in Wales and in north east England (1483 and 4534, respectively).

INTERVENTION

A coordinated range of activities for heart health promotion in Wales entailing public education campaigns along with supportive policy and infrastructure change. In the reference area no additional community heart health promotion was planned, though considerable activity did take place, "contaminating" the reference area.

MAIN OUTCOME MEASURES

Fifteen self reported behavioural indicators relating to dietary choice, smoking, frequency of exercise, and weight.

RESULTS

Positive changes (for health) in behavioural outcomes were observed among the population in Wales, including a reduction in reported smoking prevalence and improvements in dietary choice. There was no net intervention effect for the programme over and above observed change in the reference area.

CONCLUSIONS

No definite conclusions can be drawn concerning the efficacy of the programme in terms of behavioural outcomes. With hindsight, the difficulties of evaluating such a complex multifaceted intervention were underestimated. Further debate on the most appropriate methods for assessing the effectiveness of community based health promotion programmes is called for.

Lessons from the Child and Adolescent Trial for Cardiovascular Health (CATCH): interventions with children

School-based, primary prevention programs can be effective in improving children's dietary intake of fat and saturated fat and in increasing their self-reported levels of physical activity. School environments can be modified to provide healthier food options in the school cafeteria and to increase the amount of moderate to vigorous physical activity occurring during physical education class.

Zero effects in substance abuse programs. Avoiding false positives and false negatives in the evaluation of community-based programs

The evaluation of community-based programs poses special design and analysis problems. The present article focuses on two major types of errors that can occur in such evaluations: false positive--incorrectly declaring a program to be effective--and false negatives--incorrectly declaring a program to be ineffective. The evaluation of a national demonstration of community-based programs to reduce substance abuse, Fighting Back, is used to illustrate several approaches to reduce the probability of errors. Both those errors that are affected by the design and those by analytic approaches are considered. Ways to assess multiple outcomes and to match the complexity of the program with design and analytic strategies are proposed. Community trials are complex interventions, and, although they can provide very useful information, their outcomes have to be understood in terms of the constructs they test and the contexts within which they are carried out.

Research steps in the development and evaluation of public health interventions

Presented is a conceptual framework for planning intervention-related research. Altogether, nine steps in the process of developing and evaluating public health interventions are specified. This process is dynamic and iterative, and all steps are not always required, or need follow in sequence. The framework can be used to set research priorities by verifying where there is sufficient knowledge to move forward and by identifying critical information gaps. It can also help select appropriate research designs, as each step is characterized by certain types of studies. Greater effort is required to move beyond descriptive epidemiological and behavioural studies, to intervention studies. Field trials of public health interventions require particular attention as they are often neglected, despite their significance for public health policy and practice.

Participation in colorectal cancer screening: a review

The purpose of this review is to evaluate the published literature on adherence to colorectal cancer (CRC) screening with fecal occult blood testing (FOBT) and sigmoidoscopy. Specifically, the review addresses the following: 1) prevalence of FOBT and sigmoidoscopy; 2) interventions to increase adherence to FOBT and sigmoidoscopy; 3) correlates or predictors of adherence to FOBT and sigmoidoscopy; and 4) reasons for nonadherence. Other objectives are to put the literature on CRC screening adherence in the context of recently reported findings from experimental interventions to change prevention and early detection behaviors and to suggest directions for future research on CRC screening adherence. CRC screening offers the potential both for primary and for secondary prevention. Data from the 1992 National Health Interview Survey show that 26% of the population more than 49 years of age report FOBT within the past 3 years and 33% report ever having had sigmoidoscopy. The Year 2000 goals set forth in Healthy People 2000 are for 50% of the population more than 49 years of age to report FOBT within the past 2 years and for 40% to report that they ever had sigmoidoscopy. Thus, systematic efforts to increase CRC screening are warranted. To date, attempts to promote CRC screening have used both a public health model that targets entire communities, e.g., mass media campaigns, and a medical model that targets individuals, e.g., general practice patients. Most of these efforts, however, did not include systematic evaluation of strategies to increase adherence. The data on FOBT show that the median adherence rate to programmatic offers of FOBT is between 40% and 50%, depending on the type of population offered the test, e.g., patients or employees. Approximately, 50% of those initially offered testing in unselected populations will respond to minimal prompts or interventions. A salient issue for FOBT, however, is whether or not the behavior can be sustained over time. Fewer studies examined adherence to sigmoidoscopy. Adherence was highest in relatives of CRC cases and in employer-sponsored programs offered to workers at increased risk of CRC. At present, we know very little about the determinants of CRC screening behaviors, particularly as they relate to rescreening.

Joint analysis of three U.S. community intervention trials for reduction of cardiovascular disease risk

During the 1980s three comprehensive community-based heart disease prevention trials were conducted in the United States. The Stanford Five-City Project, Minnesota Heart Health Program, and Pawtucket Heart Health Program involved 12 cities; six received a 5-8 year multifactorial risk reduction program. This analysis pools data from the three studies to delineate the common intervention effects with greater sample size and power than could be attained by the single studies. Time trends were estimated for cigarette smoking, blood pressure, total cholesterol, body mass index, and coronary heart disease mortality risk in women and men aged 25-64 years. The joint estimates of intervention effect were in the expected direction in nine of 12 gender-specific comparisons; however, these were not statistically significant. The results illustrate the analytic challenges of evaluating community-based prevention trials and point to the smaller than expected net differences, rather than small sample size, as the reason for few statistically significant effects in the three U.S. prevention trials.

The effectiveness of a media-led intervention to reduce smoking among Vietnamese-American men

OBJECTIVES

This study evaluated an anti-tobacco campaign targeting Vietnamese men in San Francisco, Calif.

METHODS

The intervention included Vietnamese-language media, health education materials, and activities targeting physicians, youth, and businesses. Evaluation involved pretest and posttest cross-sectional telephone surveys and multiple logistic regression analyses designed to identify variables associated with smoking and quitting.

RESULTS

At posttest, the odds of being a smoker were significantly lower (odds ratio [OR] = 0.82, 95% confidence interval [CI] = 0.68, 0.99), and the odds of being a quitter were significantly higher (OR = 1.65, 95% CI = 1.27, 2.15), in San Francisco than in a comparison community.

CONCLUSIONS

Despite modest success, further efforts are needed to reduce smoking among Vietnamese-American men.

Understanding the variability in the effectiveness of community heart health programs: a meta-analysis

Over the past 25 years, community interventions to reduce cardiovascular disease (CVD) have been conducted around the world with very mixed results. This study uses meta-analysis to assess whether the variation in the observed effectiveness of community heart health programs (CHHP) is related to characteristics of the intervention program, the population under study, or the evaluation methods. A CHHP is defined as any primary prevention program that attempted to reduce the population burden of CVD by shifting the distribution of risk factors in a general population. To be included in the meta-analysis, a study must have utilized a reference group in the evaluation, employed a repeated independent cross-sectional measurement design, and reported sufficient outcome information for at least one of four major risk factors: smoking, total cholesterol, blood pressure, and body weight. Results of these studies are summarized with the effect size measure (Yi1-Yi2)-(Yr1-Yr2)Sr1 where Y = outcome measure, S = standard deviation of the outcome measure, 1 = baseline, 2 = follow-up. i = intervention, and r = reference community. This measure, which reports the net change in the intervention group in terms of the variability in the reference population before the start of the intervention, permits comparison across different outcome measures and facilitates the aggregation of effects across studies. Generalized least squares regression, which permits the incorporation of multiple, dependent effect sizes from a single study, was used to assess the impact of characteristics of the intervention (prevention strategy, type of mass communication, community organization, and environmental change), the population (setting, gender, year of follow-up measurement), and the evaluation design and implementation (the number of communities, matching of communities, the follow-up time, the response rate, and covariate adjustment in the analysis) on the effect sizes. The results of this analysis suggest that the characteristics of the evaluation method account for much of the heterogeneity in the outcome of CHHPs, though some intervention characteristics also play a role.

Are community health interventions evaluated appropriately? A review of six journals

OBJECTIVES

To determine if Randomized Controlled Trial (RCT) methodology was used appropriately in community health, we: (1) determined the proportion of non-randomized studies that should have been RCTs, and (2) assessed the quality of the RCTs.

METHODS

The 1992 issues of six community health journals were manually searched. Intervention studies were analyzed. Studies that did not use randomization were analyzed for feasibility and practicality of RCT methods; RCTs were analyzed for quality using a checklist. RCTs were compared with community health RCTs from The New England Journal of Medicine. The proportion of studies meeting each criterion was determined.

RESULTS

Fourteen percent of 603 studies were interventions and 4% were RCTs. Of those not using randomization, 42% should have. Mean RCT scores were significantly lower for the community health journals than for The New England Journal of Medicine. Many criteria important to quality scored poorly.

CONCLUSIONS

RCTs are underused and lack methodologic rigor in community health. Conclusions regarding the effectiveness of interventions are therefore suspect.

Multiplying health gains: the critical role of capacity-building within health promotion programs

Health outcomes in populations are the product of three factors: (1) the size of effect of the intervention; (2) the reach or penetration of an intervention into a population and (3) the sustainability of the effect. The last factor is crucial. In recent years, many health promotion workers have moved the focus of their efforts away from the immediate population group or environment of interest towards making other health workers and other organisations responsible for, and more capable of, conducting health promotion programs, maintaining those programs and initiating others. 'Capacity-building' by health promotion workers to enhance the capacity of the system to prolong and multiply health effects thus represents a 'value added' dimension to the health outcomes offered by any particular health promotion program. The value of this activity will become apparent in the long term, with methods to detect multiple types of health outcomes. But in the short term its value will be difficult to assess unless we devise specific measures to detect it. At present the term 'capacity-building' is conceptualised and assessed in different ways in the health promotion literature. Development of reliable indicators of capacity-building which could be used both in program planning and in program evaluation will need to take this into account. Such work will provide health-decision makers with information about program potential at the conclusion of the funding period, which could be factored into resource allocation decisions, in addition to the usual information about a program's impact on health outcomes. By program potential, we mean ability to reap greater and wider health gains.

HIV prevention in developed countries

HIV prevention in developed countries is marked by impressive successes and dismal failures. The successes point the way to what works; the failures highlight obstacles that must be overcome. Successes include important behavioural changes among gay and bisexual men, antiviral use to prevent vertical transmission, and securing the safety of the blood supply. New strategies are needed to reach the residual of individuals continuing with unsafe practices (a special hazard in high-prevalence areas); to reach young people who are beginning to engage in sexual relations and injection drug use; and to overcome political opposition to prevention strategies.

A comprehensive review of the effects of worksite health promotion on health-related outcomes

PURPOSE

This article provides the foundation for a series of literature reviews that critically examine the effectiveness of worksite health promotion programs. This issue reviews the exercise, health risk appraisal, nutrition and cholesterol, and weight control literatures; a future issue will review the alcohol, HIV/AIDS, multicomponent program, seat belt, smoking, and stress management literatures.

METHODS

The literature search used a four-step process that included a computerized database search, a reference search, a manual search of relevant health promotion journals, and the writing of the review by a recognized expert in the area being searched. The databases were searched from 1968 through 1994 and included Medline, Aidsline, Psychological Abstracts, Combined Health Information Database, Employee Benefits Infosource, National Prevention Evaluation Research Collection, National Resource Center on Worksite Health Promotion, National Technical Information Service, and the Substance Abuse Information database. A total of 288 articles were identified by the search, not including the 37 articles in the hypertension literature. Authors of each review were requested to incorporate additional studies not identified by the search, provide a research rating for each individual article, and a rating for the overall literature for their respective area. The authors reviewed 316 studies.

FINDINGS

The overall ratings for the reviews reported in this issue were suggestive for exercise, weak for health risk appraisals, suggestive/indicative for both nutrition and cholesterol, and indicative for weight control. The ratings for the other reviews will be reported in the subsequent issue.

CONCLUSIONS

Research reported in these reviews suggests the effectiveness of worksite health promotion programs, however, additional research is required to provide conclusive evidence of their impact.

The ecology of work and health: research and policy directions for the promotion of employee health

This article identifies new research and policy directions for the field of worksite health in the context of the changing American workplace. These directions are viewed from an ecological perspective on worksite health and are organized around three major themes: (1) the joint influence of physical and social environmental factors on occupational health, (2) the effects of nonoccupational settings (e.g., households, the health care system) on employee well-being and the implications of recent changes in these settings for worksite health programs, and (3) methodological issues in the design and evaluation of worksite health programs. Developments in these areas suggest that the field of worksite health may be undergoing a fundamental paradigm shift away from individually oriented wellness programs (provided at the worksite and aimed primarily at changing employees' health behavior) and toward broader formulations emphasizing the joint impact of the physical and social environment at work, job-person fit, and work policies on employee well-being.

Choosing a future for epidemiology: I. Eras and paradigms

To inform choices about the future of epidemiology, the present condition of epidemiology is examined, in terms of its evolution through three eras, each demarcated by its own paradigm: (1) the era of sanitary statistics with its paradigm, miasma; (2) the era of infectious disease epidemiology with its paradigm, the germ theory; and (3) the era of chronic disease epidemiology with its paradigm, the black box. The historical context in which these eras arose is briefly described. In each era, the public health was at the center of the concerns of the founders and early protagonists of the prevailing paradigm. Around this intellectual development we weave a further theme. We argue that in the present era, the public health has become less central a concern. At the same time, in epidemiology today the dominant black box paradigm is of declining utility and is likely soon to be superseded.

Translating social ecological theory into guidelines for community health promotion

Health promotion programs often lack a clearly specified theoretical foundation or are based on narrowly conceived conceptual models. For example, lifestyle modification programs typically emphasize individually focused behavior change strategies, while neglecting the environmental underpinnings of health and illness. This article compares three distinct, yet complementary, theoretical perspectives on health promotion: behavioral change, environmental enhancement, and social ecological models. Key strengths and limitations of each perspective are examined, and core principles of social ecological theory are used to derive practical guidelines for designing and evaluating community health promotion programs. Directions for future health promotion research are discussed, including studies examining the role of intermediaries (e.g., corporate decision-makers, legislators) in promoting the well-being of others, and those evaluating the duration and scope of intervention outcomes.

Policy as intervention: environmental and policy approaches to the prevention of cardiovascular disease

This paper describes the evolution of efforts to prevent cardiovascular disease, from individual health education approaches to broader community education efforts and, finally, to comprehensive and integrated programs addressing environmental, policy, and individual behavior change. Policies are divided into two areas: legislation/regulation and organizational policy. Environmental strategies are measures that alter or control the physical or social environment. Dimensions along which these strategies might be implemented are provided. Policy and environmental approaches can be justified on economic, strategic, and theoretical grounds. Experiences from other fields and other countries provide a framework for conceptualizing cardiovascular disease prevention approaches.