The empirical accuracy of uncertain inference models

Uncertainty is a pervasive feature of the domains in which expert systems are designed to function. Research design to test uncertain inference methods for accuracy and robustness, in accordance with standard engineering practice is reviewed. Several studies were conducted to assess how well various methods perform on problems constructed so that correct answers are known, and to find out what underlying features of a problem cause strong or weak performance. For each method studied, situations were identified in which performance deteriorates dramatically. Over a broad range of problems, some well known methods do only about as well as a simple linear regression model, and often much worse than a simple independence probability model. The results indicate that some commercially available expert system shells should be used with caution, because the uncertain inference models that they implement can yield rather inaccurate results

HUB City Steps: Methods and Early Findings From a Community-Based Participatory Research Trial to Reduce Blood Pressure Among African Americans

Background: Community-based participatory research (CBPR) has been recognized as an important approach to develop and execute health interventions among marginalized populations, and a key strategy to translate research into practice to help reduce health disparities. Despite growing interest in the CBPR approach, CBPR initiatives rarely use experimental or other rigorous research designs to evaluate health outcomes. This behavioral study describes the conceptual frameworks, methods, and early findings related to the reach, adoption, implementation, and effectiveness on primary blood pressure outcomes. Methods: The CBPR, social support, and motivational interviewing frameworks are applied to test treatment effects of a two-phased CBPR walking intervention, including a 6-month active intervention quasi experimental phase and 12-month maintenance randomized controlled trial phase to test dose effects of motivational interviewing. A community advisory board helped develop and execute the culturally-appropriate intervention components which included social support walking groups led by peer coaches, pedometer diary selfmonitoring, monthly diet and physical activity education sessions, and individualized motivational interviewing sessions. Although the study is on-going, three month data is available and reported. Analyses include descriptive statistics and paired t tests. Results: Of 269 enrolled participants, most were African American (94%) females (85%) with a mean age of 43.8 (SD = 12.1) years. Across the 3 months, 90% of all possible pedometer diaries were submitted. Attendance at the monthly education sessions was approximately 33%. At the 3-month follow-up 227 (84%) participants were retained. From baseline to 3-months, systolic BP [126.0 (SD = 19.1) to 120.3 (SD = 17.9) mmHg; p \u3c 0.001] and diastolic BP [83. 2 (SD = 12.3) to 80.2 (SD = 11.6) mmHg; p \u3c 0.001] were significantly reduced. Conclusions: This CBPR study highlights implementation factors and signifies the community’s active participation in the development and execution of this study. Reach and representativeness of enrolled participants are discussed. Adherence to pedometer diary self-monitoring was better than education session participation. Significant decreases in the primary blood pressure outcomes demonstrate early effectiveness. Importantly, future analyses will evaluate long-term effectiveness of this CBPR behavioral intervention on health outcomes, and help inform the translational capabilities of CBPR efforts

Improvements in Blood Pressure Among Undiagnosed Hypertensive Participants in a Community-Based Lifestyle Intervention, Mississippi, 2010

Introduction Effective strategies are needed to reach and treat people who lack awareness of or have uncontrolled hypertension. We used data from a community-based participatory research initiative, Hub City Steps, to quantify the prevalence of undiagnosed hypertension and determine the relationship between hypertension status at baseline and postintervention improvements in blood pressure and health-related quality of life. Methods Hub City Steps was a 6-month preintervention–postintervention lifestyle intervention targeting hypertension risk factors. Outcome measures were collected at baseline, 3 months, and 6 months. Generalized linear mixed models were used to test for effects by time and hypertension status. Results Of the enrolled sample (N = 269), most were overweight or obese (91%), African American (94%), and women (85%). When considering hypertension status, 42% had self-reported diagnosis of hypertension (self-reported subgroup; 84% with antihypertensive medication use); 36% had no self-reported medical history of hypertension, but when blood pressure was measured they had a clinical diagnosis of prehypertension or hypertension (undiagnosed subgroup); and 22% had no self-reported or clinical hypertension diagnosis (no hypertension subgroup). From baseline to 6 months, systolic blood pressure significantly improved for participants with self-reported hypertension [8.2 (SD, 18.2) mm Hg] and undiagnosed hypertension [12.3 (SD, 16.3) mm Hg], with undiagnosed participants experiencing the greatest improvements (P \u3c .001). Effects remained significant after controlling for covariates. Health-related quality of life significantly improved for all 3 hypertension subgroups, with no apparent subgroup differences. Conclusion This study reveals advantages of a culturally appropriate community-based participatory research initiative to reach those with undetected hypertension and effectively improve blood pressure status and health-related quality of life

Simulated reductions in consumption of sugar-sweetened beverages improves diet quality in Lower Mississippi Delta adults

Although the effects of replacing sugar-sweetened beverages (SSBs) with water on energy intake and body weight have been reported, little is known about how these replacements affect diet quality.To simulate the effects of replacing SSBs with tap water on diet quality and total energy intake of Lower Mississippi Delta (LMD) adults.Retrospective analysis of cross-sectional dietary intake data using a representative sample of LMD adults (n=1,689). Diet quality was measured using the Healthy Eating Index-2005 (HEI-2005) scores that were computed using the population ratio method. The effects of substituting SSBs with water on diet quality were simulated by replacing the targeted items’ nutrient profile with tap water's profile.Simulating the replacement of SSBs with tap water at 25, 50, and 100% levels resulted in 1-, 2.3-, and 3.8-point increases, respectively, in the HEI-2005 total score. Based on a mean daily intake of 2,011 kcal, 100% substitution of SSBs with tap water would result in 11% reduction in energy intake.Replacing SSBs with water could substantially improve the diet quality of the LMD adult population and potentially lead to significant weight loss overtime. Prioritizing intervention efforts to focus on the replacement of SSBs with energy-free drinks may be the most efficacious approach for conveying potentially substantial health benefits in this and similar disadvantaged populations

HUB City Steps: A 6-Month Lifestyle Intervention Improves Blood Pressure among a Primarily African-American Community

The effectiveness of community-based participatory research (CBPR) efforts to address the disproportionate burden of hypertension among African Americans remains largely untested. The objective of this 6-month, noncontrolled, pre-/post-experimental intervention was to examine the effectiveness of a CBPR intervention in achieving improvements in blood pressure, anthropometric measures, biological measures, and diet. Conducted in 2010, this multicomponent lifestyle intervention included motivational enhancement, social support provided by peer coaches, pedometer diary self-monitoring, and monthly nutrition and physical activity education sessions. Of 269 enrolled participants, 94% were African American and 85% were female. Statistical analysis included generalized linear mixed models using maximum likelihood estimation. From baseline to 6 months, blood pressure decreased significantly: mean (±standard deviation) systolic blood pressure decreased from 126.0±19.1 to 119.6±15.8 mm Hg, P=0.0002; mean diastolic blood pressure decreased from 83.2±12.3 to 78.6±11.1 mm Hg, P