The board formed 5 subcommittees to develop a community-driven, culturally appropriate, scientifically sound diabetes prevention intervention to benefit East Harlem residents. The Community Engagement Subcommittee developed and implemented a social marketing campaign to promote diabetes prevention, reviewed recruitment materials, developed the participant incentive strategy, and built partnerships with local leaders and activists.
The Evaluation and Policy Subcommittee developed data collection tools and procedures. They reviewed existing surveys and the board’s conceptual model, which depicted factors that influence diabetes development, and chose validated scales that were supplemented with board-developed questions to assess knowledge, attitudes, and behaviors related to diabetes prevention.31–34
Validated food frequency questionnaires and some board-developed questions assessed diet,35–38
and the Global Physical Activity Questionnaire assessed physical activity.39
To enhance responses, we supplemented the survey questions with food models and pictures of leisure-time activities. The survey, targeted to a fourth-grade reading level, was translated into Spanish and back-translated before the pilot intervention in the community began. The survey used the 2000 Census definitions of race and ethnicity.40
The subcommittee also chose to conduct interviews and focus groups with participants after the intervention.
The Intervention Subcommittee reviewed existing health education programs that have a theoretical background and show promising results.31,41–43
The group developed criteria for the intervention: be culturally sensitive; empower, educate, and motivate participants to eat healthy and be more active; inform participants about prediabetes and diabetes prevention; give control to community members; and be sustainable in community settings. The subcommittee chose to modify Healthy Eating Active Lifestyles, a derivative of the Chronic Disease Self-Management Program,44–46
a peer-lededucation program developed by Harlem residents and local weight loss experts, with promising pilot results.31
Project HEED’s curriculum followed self-efficacy theory47,48
; contained simple, actionable messages; was easily taught by lay leaders; and focused on enhancing self-efficacy to make lifestyle changes. It was presented in a workshop consisting of eight 1.5-hour sessions over 10 weeks. Topics included diabetes prevention, finding and affording healthy foods, label reading, fun physical activity, planning a healthy plate, making traditional foods healthy, and portion control. We reviewed the curriculum with scientific andpeer education experts, tested it with English (n=6) and Spanish (n=12) speakers, and revised accordingly.
The Latino Education Subcommittee reviewed all study materials to ensure that the content was appropriate and accurate for the spectrum of Spanish speakers in East Harlem. The Clinician Education Subcommittee developed a tool kit to educate primary care clinicians about prediabetes and the study. The tool kits contained educational materials, a laminated card illustrating fasting and postprandial prediabetes and diabetes glucose levels, and a form to refer patients to the study. These kits were mailed to more than 350 local clinicians.
Recruitment and Implementation
The board developed several recruitment strategies that members of the board and study personnel implemented at community sites and events, such as churches, social service agencies, senior centers, and health fairs. The most successful recruitment (accounting for 68% of participants) took place when community leaders championed the study and spearheaded recruitment at their organizations.49
Recruitment occurred in 2 phases between May and July 2007. In phase 1, we screened for eligibility. Individuals were eligible if they were aged 18 years or older, resided in East Harlem, spoke English or Spanish, were overweight (measured body mass index [BMI; defined as weight in kilograms divided by height in meters squared] ≥ 25 kg/m2), were not currently pregnant, did not have diabetes, did not use glucose-altering medications, and were able to participate in a group session. Individuals meeting these criteria gave written informed consent and were asked to return while fasting for an oral glucose tolerance test on another morning.
In phase 2, we used finger sticks to obtain fasting glucose levels measured with Accuchek glucometers (Roche, Nutley, NJ) that were calibrated daily. Participants with nondiabetes glucose levels (<126 mg/dL) drank a 75-g glucose load and had a finger stick 2 hours later. Trained staff measured weight (without shoes, in the morning while fasting) with a Siltec PS500L scale (Precision Weighing Balances, Bradford, MA). Blood pressure (in the nonprimary arm) and waist circumference (1 inch above the umbilicus) were measured twice and the readings averaged. The staff also administered the survey, which lasted approximately 30 minutes. Participants with normal glucose levels were informed that they were ineligible for the study and given information on weight loss. Those with diabetes-level glucose readings were referred to local health care providers for follow-up. The remainder, who had glucose levels in the pre-diabetes range, had venous blood drawn for hemoglobin A1c (HbA1c) and serum cholesterol levels. The board requested an additional tube of blood to be drawn from participants who consented, to be banked for future research, which would be contingent on the board approving proposals presented by researchers.
Participants were randomized to intervention or delayed intervention (in 1 year) by blocked randomization (block size = 4) by recruitment site. Intervention participants attended the workshop at community sites, often where recruitment occurred, between July 2007 and February 2008. Both groups received brief verbal and written information about prediabetes and results of all their screening tests, with a copy to take home that they could also share with their clinicians. The team repeated all measurements at 3, 6, and 12 months after enrollment. Participants received a $50 gift card and lunch at each follow-up.
Data Analysis and Follow-up
In this intention-to-treat analysis with weight as our primary outcome, we used a last-observation-carry-forward strategy to impute missing weights at follow-up. We compared participants’ self-reported demographic characteristics at baseline and performed bivariate comparisons with t tests, χ2 tests, and analysis of variance. We assessed changes in participants’ weights and behaviors between baseline and 12 months with paired t tests. We used SAS version 9.1.3 (SAS Institute Inc, Cary, NC) and defined statistical significance at .05.
We invited 93 control and intervention participants (6 withdrew at 12 months) to share their thoughts and experiences about the study in focus groups and interviews. Participants were separated by trial arm and asked about their reasons for participating and their reactions to recruiting, screening, and the intervention itself. The board wrote an interview guide, which was followed by experienced moderators. Audiotapes were transcribed and, when appropriate, translated. A community coinvestigator and a board member developed themes, coded groups, and compared results to calculate interrater reliability.