Participation In Prevention Trials Research Articles

Effects of Incentive Items on Participation in a Randomized Chemoprevention Trial

Behavioral research has an important role in increasing and maintaining participation in disease prevention trials, both in interventions and in follow-up visits. We conducted a randomized experiment among participants in the lung cancer chemoprevention trial, CARET (Carotene and Retinol Efficacy Trial) to test the effects of providing two incentives on retention. The items used for this study were a Certificate of Appreciation and one of two lapel pins, provided in a 2 2 design. Providing incentives, whether alone or in combination, had no statistically significant effect on retention by the two-year follow-up point. The successful implementation of this randomized incentive study has two implications for future research: (1) study of behavioral interventions and issues is feasible in the context of large controlled trials of disease end-points; and (2) such study is necessary to determine whether selected incentives can increase retention.

Response rates to six recruitment mailing formats and two messages about a nutrition program for women 50–79 years old

Recruiting participants for large prevention trials is time consuming and costly. In order to test various recruitment techniques, we conducted two studies of response rates to recruitment mailings for the Women's Health Trial. The potential participants, 50- to 79-year-old women, were requested to return an enclosed postcard to learn more about the trial. In the first study, we sent at random either a short or a long message to a group of University of Miami personnel ( N = 862) and a Dade County cohort ( N = 2964). More university women responded to the short message than to the long message (22.4% vs 16.4%, p = 0.024). Similarly, more of the Dade County cohort replied to the short message than to the long one (12.1% vs 9.6%, p = 0.027). The long message listed details of the intervention (e.g., modifying recipes) that some women may have used to decide they were not interested in participating. In the second study, we examined response rates to two different ways of addressing the mailing, i.e., handwritten envelopes and machine-printed labels; we also evaluated three methods for delivering the short message: (1) formal invitation, (2) business letter with an inside name and address of the recipient, and (3) business letter without the recipient's name and address. Response rates were similar between the methods of addressing envelopes and among the three vehicles for the message, suggesting that the least costly method of mailing should be used.

Stat Bite: Breast Cancer Risk in Prevention Trial Participants

Stat Bite: Breast Cancer Risk in Prevention Trial Participants

Lipoprotein(a) Levels and Risk of Coronary Heart Disease in Men

To examine the relationship between elevated levels of lipoprotein(a) [Lp(a)] and coronary heart disease (CHD) risk in a prospective study. Nested case-control study. The cohort consisted of participants in the Lipid Research Clinics Coronary Primary Prevention Trial. Lipid research clinics. The Lipid Research Clinics Coronary Primary Prevention Trial participants (n = 3806) were men, aged 35 to 59 years, with plasma cholesterol levels of 6.85 mmol/L (265 mg/dL) or greater, low-density lipoprotein cholesterol levels of 4.91 mmol/L (190 mg/dL) or greater, and triglyceride levels less than 3.39 mmol/L. Subjects were randomly assigned to either cholestyramine or placebo treatment. The Lp(a) levels were measured in plasma samples obtained prior to randomization in 233 cases (participants who developed CHD in the course of the study) and 390 matched CHD-free controls. A total of 96.95% of the subjects were white, 2.25% were black, and 0.80% were of other race. Coronary heart disease (either fatal or nonfatal) events during a follow-up of 7 to 10 years. The Lp(a) levels were significantly higher (21%) in cases than in controls (23.7 mg/dL [0.59 mmol/L] and 19.5 mg/dL [0.49 mmol/L], respectively; P < .02). This difference was still statistically significant (P < .01) after controlling for age, body mass index, cigarette smoking, blood pressure, low-density lipoprotein cholesterol level, and high-density lipoprotein cholesterol level. When subjects were divided by treatment, both cholestyramine-treated and placebo-treated CHD subjects had Lp(a) levels 20% to 22% greater than their matched controls. However, possibly because of smaller sample sizes, these differences were no longer statistically significant. Our data are consistent with the concept that an elevated Lp(a) level is an independent risk factor for CHD in hypercholesterolemic white men.

Mediational screening as a model for prevention research

Examined here is Pillow, Sandler, Braver, Wolchik, and Gersten's (this issue) strategy for screening prevention trial participants. The reviewer concludes that their selection strategy should increase the statistical power of prevention outcome studies, increase intervention cost effectiveness, and help to prevent their possible iatrogenic effects. Also, their model points up inadequacies in the longitudinal data on which most prevention strategies are based, and their model could well serve as a template for future research.

Community Intervention Trial for Smoking Cessation (COMMIT): Opportunities for community psychologists in chronic disease prevention

Opportunities for participation in chronic disease prevention programs are discussed in the context of a description and analysis of the National Cancer Institute's Community Intervention Trial for Smoking Cessation (COMMIT). COMMIT involves 11 matched pairs of communities with random assignment to the intervention condition within each pair. The 4-year intervention is guided by a partly standardized protocol and embodies a number of community psychology principles. The relative congruence of COMMIT with community psychology principles and methods is discussed with particular emphasis on Kelly's (1988) model of community research. Community psychology's participation in chronic disease prevention trials requires understanding of the programmatic framework of National Institutes of Health prevention research and recognition of the constraints imposed by the framework on community psychology practices.