The incidence of preventable chronic diseases is disproportionally high among African Americans and could be reduced through diet and physical activity interventions. Our objective was to systematically review the literature on clinical outcomes of diet and physical activity interventions conducted among adult African American populations in the United States.
We used the Preferred Reporting Items for Systematic Review and Meta Analysis construct in our review. We searched Medline (PubMed and Ovid), Cochrane, and DARE databases and restricted our search to articles published in English from January 2000 through December 2011. We included studies of educational interventions with clinically relevant outcomes and excluded studies that dealt with nonadult populations or populations with pre-existing catabolic or other complicated disorders, that did not focus on African Americans, that provided no quantitative baseline or follow-up data, or that included no diet or physical activity education or intervention. We report retention and attendance rates, study setting, program sustainability, behavior theory, and education components.
Nineteen studies were eligible for closer analysis. These studies described interventions for improving diet or physical activity as indicators of health promotion and disease prevention and that reported significant improvement in clinical outcomes.
Our review suggests that nutrition and physical activity educational interventions can be successful in improving clinically relevant outcomes among African Americans in the United States. Further research is needed to study the cost and sustainability of lifestyle interventions. Further studies should also include serum biochemical parameters to substantiate more specifically the effect of interventions on preventing chronic disease and reducing its incidence and prevalence.
Education and community-based programs in disease prevention and health promotion played an important role in achieving
Growing awareness of the role of a healthful diet and physical activity in reducing chronic disease has greatly increased the volume of recent literature on the subject, so that many reviews (
We used the Preferred Reporting Items for Systematic Reviews and Meta Analysis (PRISMA) (
Nineteen studies (
Data-filtering process used to select final 19 studies included in systematic review of interventions for improving nutrition and physical activity behaviors among adult African American populations, January 2000 through December 2011. Flow diagram for study selections adapted from PRISMA (
Our initial search used a combination of the following key words: African American, nutrition, diet, physical activity, weight loss, and intervention. The inclusion criteria were 1) that the article addressed educational interventions in diet and physical activity with clinically relevant outcomes (eg, changes in weight, body mass index (BMI [kg/m2]), body fat percentage, cholesterol, triglycerides, blood pressure) and 2) that the educational interventions included at least 1 direct or indirect instructional strategy to educate participants on how to increase daily physical activity and fruit and vegetable consumption or how inactivity and poor dietary patterns can negatively affect health. We excluded studies that dealt with nonadult populations or populations with pre-existing catabolic or other complicated disorders (eg, cancer, cirrhosis, HIV/AIDs, heart failure); studies that did not focus on African Americans; studies that provided no quantitative baseline or follow-up data; and studies that included no diet or physical activity education or intervention. Data were extracted by 1 reviewer and verified by a second. Information on the following components were collected: study settings, theoretical principles incorporated into the intervention design, study outcomes, intervention details, recruitment strategies, attendance and retention rates of the participants, sustainability of the achieved changes in health behaviors, and provision of physical activity and nutrition education.
Among the 19 studies reviewed (5.3% of nonduplicated identified articles), 1 included participants of various races and ethnicities (
| Study Components | Description |
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| Sample | N = 508 African Americans (341 women, 167 men) aged ≥18 years with type 2 diabetes. Unable to determine mean age and standard deviation [SD] for participants because of inability to distinguish African American participants from other races. Three groups: metformin group, 163 women and 58 men who received standard lifestyle recommendations plus metformin; placebo group, 163 women and 57 men who received standard lifestyle recommendations plus placebo; lifestyle group, 154 women and 50 men who received intensive lifestyle modification. |
| Theory | None noted |
| Study outcome(s) | Weight |
| Intervention | Duration: 6 months. Location: various clinical centers. Design: individual or one-on-one sessions; consisted of 16 diet and lifestyle sessions using the NIH DPP over 4 months from initiation of intervention with two additional monthly follow up sessions. Education: diet and PA. Follow-up: at 6 months, 12 months, 18 months, 24 months, and 30 months. |
| Attendance and retention | Attendance: not reported. Retention: 91% women, 87% men. |
| Clinical outcomes and results | Weight loss: 4.8 kg, women, 2.1 kg, men. Results significant over 30 month ( |
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| Sample | 48 African American women and men aged 30–55 y (mean 46.8 y, SD, 6.4 y), BMI ≥35 kg/m2. Two groups: initial PA, delayed PA. |
| Theory | None noted |
| Study outcome | Weight, waist circumference. abdominal adiposity, visceral fat, body composition (DXA measure), BP. |
| Intervention | Duration: 12 months. Location: university. Design: group, individual, and telephone contacts (1st–6th month, 3 group and 1 individual contacts/month; 6th–12th month, 2 group sessions and 2 telephone contacts/month). Diet prescribed for both groups to achieve 8% to 10% weight loss over 12 months; meal replacements offered during first 6 months. PA goals for both groups to achieve 60 minutes, 5 days per week, moderate-intensity PA. Delayed PA group started PA at 6th month. Education: diet and physical activity. Follow-up: 6 months, and 12 months. |
| Attendance and retention | Attendance: not reported. Retention: initial group, 90% at 6 months, 73% at 12 months; delayed group, 90% at 6 months, 83% at 12 months. Study not African American- specific; however, no difference reported between white and African American participants. |
| Clinical outcomes and results | Weight: 12.1 kg decrease for initial group; 9.9 kg decrease for delayed group ( |
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| Sample | Women (N = 70) with type 2 diabetes aged ≥18 years (mean, 62.8 y; SD, 10.1 y). Two groups: group 1 (n = 34), dance intervention plus usual care; group 2 (control group) (n = 36), usual care. |
| Theory | Social cognitive learning theory |
| Study outcome(s) | HbA1c, weight, BIA, BP |
| Intervention | Duration: 12 weeks. Location, community center. Design, group, 60-minute dance intervention 2 times per week, led by experienced African American instructor. Education: diet and physical activity. Follow up: 12th week. |
| Attendance, retention | Attendance: not reported. Retention: 84%. |
| Clinical outcomes and results | HbA1c: decrease 0.5% in dance group ( |
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| Sample | Women (n = 529) ≥40 y (mean, 53.1 y; SD, 9.3 y). Three groups: group without spirituality (n = 188); group 2, group with spirituality (n = 267); group 3, self-help group, no spirituality (n = 74). |
| Theory | None noted |
| Study outcome(s) | Weight, BMI, waist circumference, BP, blood lipids, FG, energy intake, smoking, PA |
| Intervention | Duration: 20 weeks. Location: 16 churches. Design: weekly group meetings of 30 to 45 minutes with nutrition education and 30 minutes moderate aerobic exercise. First 20 weeks, group led by research staff; thereafter, by church lay health leader. Education: diet and PA. Follow-up: 6 months, 12th months. |
| Attendance and retention | Attendance, 33%–50% overall. Retention: 71.2%. |
| Clinical outcomes and results | Weight: 0.5 kg decrease in without-spirituality and spirituality groups ( |
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| Sample | Overweight or obese women (n = 37) and men (n = 3), ≥20 y of age (mean, 44.0 y, SD, 10.0 y). Two groups: group intervention (n = 20), individual intervention (n = 20). |
| Theory | None noted |
| Study outcome(s) | PA, weight, body composition (DXA measure), blood lipids, FG, BP, quality of life |
| Intervention | Duration: 6 months. Location: church. Design: group and individual (or one-one-one). Intervention conducted by lay health educators with extensive training. Group intervention had 6 monthly meetings; individual intervention had 15 meetings over 6 months. Education: diet and PA. Follow-up: 6th month. |
| Attendance and retention | Attendance: not reported. Retention: 90%. |
| Clinical outcomes and results | Weight: mean loss 3.3 kg in both groups ( |
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| Sample | N = 56 (54 women, 2 men). Mean age, 40.4 y; SD, not reported. Two groups: intervention (n = 35); delayed (n = 22). |
| Theory | None noted |
| Study outcome(s) | Weight, BP, cholesterol |
| Intervention | Duration: 8 weeks. Location: university. Design: both groups led by African American instructor; both groups prescribed progressive diet (1st week, rice diet, 1,000 kcal, 7% fat; 3rd week, added animal protein (eggs, milk, cheese); 5th week, advanced animal protein (lean meat [chicken/fish], 1,200 kcal, 14% fat). Delayed group began intervention after 8 weeks. Participants paid $106 for university employees and $170/nonemployees to cover food costs. Education: diet and physical activity. Follow-up: 8 weeks. |
| Attendance and retention | Attendance: 79%. Retention: 77%. |
| Clinical outcomes and results | Weight: 32.6 kg mean loss ( |
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| Sample | N = 24 women, aged 18 to 45 (mean, 39 y; SD, 5.5 y), sedentary, with normal BP or stage 1 hypertension. Two groups: group 1 (n = 13), exercise; group 2 (n = 10), no exercise. |
| Theory | None noted |
| Study outcome(s) | BP, PA |
| Intervention | Duration: 8 weeks. Location: participant’s home. Design: individual. Exercise group visited at home to encourage lifestyle PA (eg, walking, stair climbing) for 10 minutes, 3 times a day, 5 days a week following NIH-DPP program. Education: PA only. Follow-up: 8th week. |
| Attendance and retention | Attendance: not reported. Retention: 96%. |
| Clinical outcomes and results | SBP: 6.4 mm Hg decrease ( |
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| Sample | N = 281 women, aged 40 to 65 y (mean, 48.6 y; SD, 6.0 y). Two groups: intervention (n = 156), control (n = 125). |
| Theory | None noted |
| Study outcome(s) | BMI, waist circumference |
| Intervention | Duration: 48 weeks. Location: community health centers. Design: intervention group, 4 targeted workshops followed by weekly telephone calls over 24 weeks. Education: PA only. Follow-up: week 24 and week 48. |
| Attendance and retention | Attendance: 58%, intervention; 25%, control. Retention: 42.7%. |
| Clinical outcomes and results | BMI: 0.7 decrease in intervention group; 0.2 decrease in control group; no significant difference between groups. Waist circumference: 1.1 cm decrease in intervention group ( |
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| Sample | N = 201 (128 women, 73 men) aged ≥20 y (mean, 59.2 y; SD, 1.1 y) with diabetes diagnosis. Two groups: special intervention (n = 117 [75 women, 17 men]); minimal intervention (n = 84 [53 women, 31 men]). |
| Theory | None noted |
| Study outcome(s) | Diet, PA, diabetes self-management |
| Intervention | Duration: 48 weeks. Location: community health centers. Design: special intervention group, 8-month intensive phase with 1 counseling visit, 12 group sessions, telephone calls, 3 postcards, and 4-month reinforcement phase with telephone calls; minimal intervention group, standard education pamphlets by mail. Education: diet and PA. Follow-up: 8th and 12th months. |
| Attendance and retention | Attendance: 67% special intervention group and 70%, minimal intervention group at 8th month; 68% special intervention group, 67% minimal intervention group at 12th month. Retention: 84.5%. |
| Clinical outcomes and results | HbA1c: 0.4% decrease in special intervention; no decrease in minimal intervention ( |
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| Sample | N = 152 (123 women, 29 men with diabetes). Mean age, 60.3 y; SD, 8.6 y. Three groups: intensive-lifestyle intervention (n = 49); reimbursable-lifestyle intervention (n = 47); control (usual care) (n = 56). |
| Theory | None noted |
| Study outcome(s) | Weight |
| Intervention | Duration: 12 months. Location: community health centers. Design: intensive lifestyle intervention group met weekly with nutritionist for first 4 months, every other week for next 2 months, once monthly for remaining 6 months; reimbursable lifestyle intervention group had key elements of intensive lifestyle intervention group delivered in four 1-hour sessions (equivalent to the amount of allowable time to reimbursed for nutrition counseling by Medicaid) over 12 months with 3 group sessions and 1 individual session; program modeled after NIH DPP. Education: diet and PA. Follow-up: 3rd, 6th, and 12th months. |
| Attendance and retention | Attendance: not reported. Retention: 81%. |
| Clinical outcomes and results | Weight: 2.2 kg loss in intensive lifestyle intervention group; significant compared with baseline ( |
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| Sample | N = 59 overweight/obese women. Mean age 48.5 y; SD, 21.9 y. Two groups: faith-based weight-loss intervention (n = 30), weight-loss intervention (n = 29). |
| Theory | SCT |
| Study outcome(s) | Weight, dietary fat consumption, PA |
| Intervention | Duration: 12 weeks. Location: hospital. Design: Groups met 2 times per week; weight-loss group received culturally tailored intervention; faith-based group received same intervention with addition of a faith/spirituality component. Education: diet and PA. Follow-up: 12th week. |
| Attendance and retention | Attendance: 54% faith-based weight-loss group; 54%, weight-loss group. Retention: 77%, faith-based weight-loss group; 79% weight-loss group. |
| Clinical outcomes and results | Weight loss: 2.6 kg, faith-based weight-loss group ( |
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| Sample | N = 269 (229 women, 40 men). Mean age, 43.8 y; SD, 12.1 y. |
| Theory | Community-based participatory research, transtheoretical model |
| Study outcome(s) | BP, PA |
| Intervention | Duration: 18 months. Location: community. Design: trained and paid community coach-led groups participated in intervention with monthly 90-minute group education and PA sessions; used pedometers and diaries. Education: PA only. Follow-up: 3rd, 6th, 12th, and 18th months. |
| Attendance and retention | Attendance: 33.6%. Retention: 84%. |
| Clinical outcomes and results | SBP: 6 mm Hg decrease ( |
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| Sample | N = 71 women aged ≥60 years (mean, 72.8 y; SD, 7.7 y). Two groups: intervention (n = 37); control (n = 34). |
| Theory | None noted |
| Study outcome(s) | Weight, BP, PA, chronic pain |
| Intervention | Duration: 6 months. Location: church. Design: Both groups received 45 minutes PA per week for 8 weeks and then once monthly for 4 months. Intervention group had additional 45 minutes PA faith-based curriculum; both groups used pedometer. Education: diet and PA. Follow-up: 6th month. |
| Attendance and retention | Attendance: 85% (75% of classes). Retention: 87%. |
| Clinical outcomes and results | Weight: 1.0 kg decrease, intervention group; 0.7 kg decrease, control group; no significant difference between groups. BMI: not reported. SBP: 12.5 mm Hg decrease, intervention group; 1.5 mm Hg decrease control group ( |
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| Sample | N = 366 women. Mean age, 45.5 y; SD, 10.5 y. Two groups: intervention group: (n = 188); control group, (n = 178). |
| Theory | SCT, socio-ecological model |
| Study outcome(s) | Diet quality (fiber, fruits and vegetables), body fat percentage (BIA measure), waist circumference, fitness |
| Intervention | Duration: 8 weeks. Location: local gym. Design: group; 1 hour PA, 1 hour nutrition lectures and activities; participants given 1 year free gym membership; administered food frequency questionnaire; recorded 1 mile run/walk; waist circumference, percentage body fat (BIA measure). Education: diet and PA. Follow-up: 2nd, 6th, 12th month. |
| Attendance and retention | Attendance: 80%–95% 1 or more sessions. Retention: >70%. |
| Clinical outcomes and results | BMI: marginal decrease ( |
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| Sample | N = 20 overweight women. Mean age, 51.4 years; SD, 8.9 y. |
| Theory | SCT, health behavior theory |
| Study outcome(s) | Social support, food intake, weight, BMI, PA |
| Intervention | Duration: 6 months. Location: community center. Design: 2 weekly group classes: 1st hour, education; 2nd hour, exercise. Education: diet and PA. Follow-up: 6th month. |
| Attendance and retention | Attendance: 55% (75% of classes). Retention: 87%. |
| Clinical outcomes and results | Weight: 14.5 kg loss ( |
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| Sample | N = 46 (26 women, 20 men) aged ≥18 years at risk for diabetes. Mean age, 52.1 y; SD not reported. |
| Theory | None noted |
| Study outcome(s) | Weight, BP, FG |
| Intervention | Duration: 4 months. Location: church. Design: individual; 16 NIH DPP sessions. Education: diet and PA. Follow-up: 6th, 12th month. |
| Attendance and retention | Attendance: not reported. Retention: 65%. |
| Clinical outcomes and results | Weight: 2.5 kg loss at 6 months, significant compared with baseline ( |
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| Sample | N = 736 African American (540 women, 196 men) aged ≥ 25 years (mean, 52.3 y; SD, 9.5 y); BMI 25–45 kg/m2. Phase I trial. |
| Theory | SCT, transtheoretical model |
| Study outcome(s) | Weight, PA |
| Intervention | Duration: 20 weeks. Location: 4 clinical research centers. Design: group conducted by nutrition and behavioral counselors with goals of achieving ≥4 kg weight loss and 180 minutes per week moderate-intensity PA (need to enter Phase II trial). Education: diet and PA. Follow-up: 0, 20 weeks (participants achieving goals were entered into Phase II). |
| Attendance and retention | Attendance: 71% (not African American specific). Retention: 92% (not African American specific). |
| Clinical outcomes and results | Weight: men, 5.4 kg mean loss; women, 4.1 kg mean loss ( |
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| Sample | N = 10 (7 women, 3 men) aged ≥18 years (mean and SD note reported) with prediabetes (FG 100–125mg/dl). |
| Theory | None noted |
| Study outcome(s) | Attendance, changes in FG, weight, BMI |
| Intervention | Duration: 6 weeks. Location: church. Design: 6-session group program (nutrition, PA, behavior change) derived from 16-session intensive lifestyle arm of NIH DPP. Education: diet and PA. Follow-up: 6 weeks, 6th month, 12th month. |
| Attendance and retention | Attendance: 78% overall sessions and participants. Retention: 90%. |
| Clinical outcomes and results | Weight: 4 kg loss. BMI: 1.7 decrease. FG: 7 mg/dL decrease. SBP: 3 mm Hg decrease. DBP: 5 mm Hg decrease. Results significant compared with baseline ( |
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| Sample | N = 22 breast cancer survivors, women. Mean age, 55.0 years; SD, not reported. |
| Theory | Health behavior theory, SCT. |
| Study outcome(s) | Weight, BP, FG |
| Intervention | Duration: 2 months. Location: church. Design: individual; 16 sessions on exercise behaviors. Education: diet and PA. Follow-up: 3rd month. |
| Attendance and retention | Attendance: not reported. Retention: 65%. |
| Clinical outcomes and results | BMI: 0.38 decrease ( |
Abbreviations: BIA, bioelectrical impedance analysis; BMI, body mass index; BP, blood pressure; DBP, diastolic blood pressure; DXA, dual energy X-ray absorptiometry; FG, fasting plasma glucose; HbA1c, hemoglobin A1C; HDL, high-density lipoprotein; HOMA-IR, homeostasis model assessment-estimated insulin resistance; NIH DPP, National Institute of Health Diabetes Prevention Program; LDL, low-density lipoprotein; PA, physical activity; SBP, systolic blood pressure.
References refer to the same study. Intervention results were published separately from attendance rates, retention rates, and strategies.
References refer to the same study. Data were divided by physical activity- and diet-related content and were published separately.
Overall, the nutritional and physical activity interventions we reviewed reduced risk for chronic diseases by succeeding in improving clinically relevant outcome measures, including weight loss (
The improvements in serum biochemical markers, including HDL, LDL, and some other health indicators (eg, triglycerides, blood glucose levels) were measured and observed in just a few of the studies (
The majority of the 19 studies we reviewed were conducted in churches (n = 5), clinical or community health centers (n = 5), or other community locations (ie, community centers or local gyms) (n = 4). Remaining intervention locations were home-based (n = 1), universities (n = 2), a residence (n = 1), and a hospital (n = 1).
Recruitment methods varied depending on the intervention setting. Researchers conducting faith-based interventions (
Attendance rates at the 10 intervention programs that reported attendance varied from 33.0% to 95.0% (
Although interventions show evidence of short-term (range, 2–6 months) improvements in diet and exercise habits, there was limited follow-up to prove that these changes were long-term and that they continued beyond the intervention. Of 6 studies that followed up with participants beyond the intervention, 4 studies (
Of the studies reviewed, 7 (
All of the 19 educational interventions reviewed (
Because it has been confirmed that African Americans have an increased burden of chronic disease risk that is exacerbated by unhealthy diets and limited physical activity (
In a more recent, similar review, Pezmeki and Jennings (
Although all 19 of the studies we reviewed demonstrated significance in various clinical outcomes, the most frequently reported variables were weight, BMI, SBP, and DBP. It was apparent that the African American participants in populations targeted by selected interventions were obese and prehypertensive. Mean decreases in SBP and DBP were sufficient to decrease blood pressure but not the number of people diagnosed with prehypertension (
Our findings are consistent with published research results that support using community-based settings for implementing interventions to improve diet and physical activity among African Americans. Our findings also indicate that churches may be useful in reaching communities beyond their congregations for study participation; several studies successfully recruited and reported changes among participants who did not attend church at the study’s location (
Eleven studies (
This review found no differences in select clinical outcomes (eg, weight, SBP, and DBP) between programs that offered physical activity education and those that offered physical activity plus diet education, although few physical activity-education only interventions were available for comparison. One study included in this review (
Compared with programs aimed at improving physical activity and diet in predominately white populations, mean attendance and retention rates at programs for African Americans were lower. The mean attendance rate for studies with predominantly white participants was 95.0% (
Our study had limitations. Our review was only as good as the available studies analyzed. Not all included studies used randomization for participant allocation, and some of the results may show allocation bias. Another limitation is publication bias. Many relevant studies that were unpublished because of nonsignificant results would have been included in this review if published. Other analyzed studies did not use control groups for comparison, which may have introduced some experimenter bias for the overall conclusions.
This review provides researchers with current information on intervention program effectiveness and provides policy makers and health care practitioners with evidence about whether nutrition education and physical activity promotion interventions are valuable methods for improving the health of African Americans. The authors identified from the reviewed literature a common protocol for implementation of lifestyle interventions to prevent chronic disease in African American adults (
Nutrition and physical activity interventions promote positive changes in the health behaviors of adult African Americans by providing them with knowledge and resources about disease prevention. The reviewed studies have shown that these health interventions had a positive effect on the participants’ dietary choices and physical activity habits, which translated to clinically relevant outcomes in communities, churches, and health clinics. Using health education and interventions designed to teach African American adults about healthy choices (eg, proper nutrition and adequate exercise) empowers them to make necessary lifestyle changes. Thus, potential exists for reducing preventable risks for diseases and comorbidities while positively affecting the health of the community. Future interventions should incorporate theoretical models appropriate for health-related issues and randomized controlled trial design into the basis of their programming, because this gives credence to evidence-based research.
The current literature suggests that more research is needed to determine the cost and sustainability of lifestyle intervention programs. We noticed in our review that the costs of designing and implementing interventions were rarely published, offering no guidance as to what the typical costs are of interventions. Additionally, a cost-benefit analysis would facilitate the awareness and spread of information about public policy and funding allocation. Sustainability of improved diet and physical activity behavior is also rarely noted. Programs are implemented and results are documented, but whether targeted populations are able to further or maintain progress after the cessation of the intervention is still in question.
Further research is required to substantiate the link between the intervention-induced diet and physical activity changes and related disease-risk biochemical markers. Such data could be documented on a clinical level, and the information on population disease-risk characteristics could become available. This type of data also adds to the potency of the argument for funding public education programs. Although many interventions have proven successful for African American populations, filling the information gaps will promote and substantiate further progress of intervention research and a subsequent improvement in overall health of African Americans and a reduction in population health disparities.
This publication was partially funded by USDA/CSREES/NRI #2004-05287 (principal investigator, JZ Ilich).
The opinions expressed by authors contributing to this journal do not necessarily reflect the opinions of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions.
1. Identify target population.
2. Identify appropriate location for intervention.
3. Develop relationships with appropriate leaders.
4. Recruit members of the community, staff of a clinical center, university professors/students, etc., to represent the implementation team.
5. Utilize focus groups to determine the needs, values, health beliefs of intervention population.
6. Develop appropriate agenda/schedule for all phases of the intervention, including introduction of the project, baseline (before measurements) and follow-up measurements, and programming.
7. Publicize brand of the project, project goals, program dates, and recruitment criteria.
8. Begin recruitment with signed consent forms and appropriate privacy protection procedures.
9. Implement the program with the goals and interests of the target population in mind.
10. Support participation via phone calls, letters, e-mails, and reminders of sessions.
11. Increase interest by creating newsletters about study milestones and some individual or group progress.
12. If applicable, create Web page for the study with accompanying accesses to Twitter, Facebook, and such.