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Dive into the research topics where Christopher Gamboa is active.

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Featured researches published by Christopher Gamboa.


JAMA | 2012

Association of Race and Sex With Risk of Incident Acute Coronary Heart Disease Events

Monika M. Safford; Todd M. Brown; Paul Muntner; Raegan W. Durant; Stephen P. Glasser; Jewell H. Halanych; James M. Shikany; Ronald J. Prineas; Tandaw E. Samdarshi; Vera Bittner; Cora E. Lewis; Christopher Gamboa; Mary Cushman; Virginia J. Howard; George Howard

CONTEXT It is unknown whether long-standing disparities in incidence of coronary heart disease (CHD) among US blacks and whites persist. OBJECTIVE To examine incident CHD by black and white race and by sex. DESIGN, SETTING, AND PARTICIPANTS Prospective cohort study of 24,443 participants without CHD at baseline from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort, who resided in the continental United States and were enrolled between 2003 and 2007 with follow-up through December 31, 2009. MAIN OUTCOME MEASURE Expert-adjudicated total (fatal and nonfatal) CHD, fatal CHD, and nonfatal CHD (definite or probable myocardial infarction [MI]; very small non-ST-elevation MI [NSTEMI] had peak troponin level <0.5 μg/L). RESULTS Over a mean (SD) of 4.2 (1.5) years of follow-up, 659 incident CHD events occurred (153 in black men, 138 in black women, 254 in white men, and 114 in white women). Among men, the age-standardized incidence rate per 1000 person-years for total CHD was 9.0 (95% CI, 7.5-10.8) for blacks vs 8.1 (95% CI, 6.9-9.4) for whites; fatal CHD: 4.0 (95% CI, 2.9-5.3) vs 1.9 (95% CI, 1.4-2.6), respectively; and nonfatal CHD: 4.9 (95% CI, 3.8-6.2) vs 6.2 (95% CI, 5.2-7.4). Among women, the age-standardized incidence rate per 1000 person-years for total CHD was 5.0 (95% CI, 4.2-6.1) for blacks vs 3.4 (95% CI, 2.8-4.2) for whites; fatal CHD: 2.0 (95% CI, 1.5-2.7) vs 1.0 (95% CI, 0.7-1.5), respectively; and nonfatal CHD: 2.8 (95% CI, 2.2-3.7) vs 2.2 (95% CI, 1.7-2.9). Age- and region-adjusted hazard ratios for fatal CHD among blacks vs whites was near 2.0 for both men and women and became statistically nonsignificant after multivariable adjustment. The multivariable-adjusted hazard ratio for incident nonfatal CHD for blacks vs whites was 0.68 (95% CI, 0.51-0.91) for men and 0.81 (95% CI, 0.58-1.15) for women. Of the 444 nonfatal CHD events, 139 participants (31.3%) had very small NSTEMIs. CONCLUSIONS The higher risk of fatal CHD among blacks compared with whites was associated with cardiovascular disease risk factor burden. These relationships may differ by sex.


American Journal of Nephrology | 2011

Chronic Kidney Disease and Risk of Death from Infection

Henry E. Wang; Christopher Gamboa; David G. Warnock; Paul Muntner

Background: Infection, bacteremia and sepsis are major sources of morbidity and mortality in patients with end-stage renal disease. This study sought to determine the association between predialysis chronic kidney disease (CKD) and infection-related mortality. Methods: We analyzed participants in the Third National Health and Nutrition Examination Survey (NHANES III). The study included adults ≧45- years-old without end-stage renal disease. Estimated glomerular filtration rate (eGFR) was categorized as ≧60, 45–59.9 and <45 ml/min per 1.73 m2, and urinary albumin-to-creatinine ratio (ACR) as <30, 30–299.9 and ≧300 mg/g. The study identified infection-related mortality, including septicemia, respiratory, abdominal and gastrointestinal, cardiac, kidney and genitourinary, neurologic, and other infections over a median of 13 years using the National Death Index. Results: Of 7,400 participants included in the study, 206 died from infections. Compared to individuals with eGFR ≧60 ml/min per 1.73 m2, infection-related mortality was higher for those with lower eGFR [adjusted HR = 1.36 (95% CI: 0.81, 2.30) and 2.36 (1.04, 5.38) for eGFR of 45–59.9 and <45 ml/min per 1.73 m2, respectively; p trend = 0.06]. Compared to individuals with ACR <30 mg/g, infection-related mortality was higher for ACR levels of 30–299 and ≧300 mg/g [adjusted HR = 1.68 (95% CI: 0.97, 2.92) and 2.84 (0.92, 8.74), p trend = 0.02]. Conclusions: Reduced eGFR and albuminuria are associated with increased risk for infection-related mortality. Efforts are needed to reduce its incidence and mitigate the effects of infections among individuals with CKD.


Journal of the American Heart Association | 2013

Perceived Stress Is Associated With Incident Coronary Heart Disease and All‐Cause Mortality in Low‐ but Not High‐Income Participants in the Reasons for Geographic And Racial Differences in Stroke Study

Nicole Redmond; Joshua S. Richman; Christopher Gamboa; Michelle A. Albert; Mario Sims; Raegan W. Durant; Stephen P. Glasser; Monika M. Safford

Background Perceived stress may increase risk for coronary heart disease (CHD) and death, but few studies have examined these relationships longitudinally. We sought to determine the association of perceived stress with incident CHD and all‐cause mortality. Methods and Results Data were from a prospective study of 24 443 participants without CHD at baseline from the national Reasons for Geographic And Racial Differences in Stroke (REGARDS) study cohort. Outcomes were expert‐adjudicated acute CHD and all‐cause mortality. Over a mean follow‐up of 4.2 (maximum 6.9) years, there were 659 incident CHD events and 1320 deaths. Analyses were stratified by income level because of significant interactions with stress. For individuals with low income, 3529 (35.4%) reported high stress, and for those with high income, 2524 (22.1%) did so. Compared with reporting no stress, those reporting the highest stress had higher risk for incident CHD if they reported low income (sociodemographic‐adjusted HR 1.36, 95% CI: 1.04, 1.78) but not high income (sociodemographic‐adjusted HR 0.82, 95% CI: 0.57, 1.16); the finding in low income individuals attenuated with adjustment for clinical and behavioral factors (HR 1.29, 95% CI: 0.99, 1.69, P=0.06). After full adjustment, the highest stress category was associated with higher risk for death among those with low income (HR 1.55, 95% CI: 1.31, 1.82) but not high income (HR 1.13, 95% CI: 0.88, 1.46). Conclusions High stress was associated with greater risks of CHD and death for individuals with low but not high income.


Clinical Journal of The American Society of Nephrology | 2011

All-cause Mortality in Hemodialysis Patients with Heart Valve Calcification

Paolo Raggi; Antonio Bellasi; Christopher Gamboa; Emiliana Ferramosca; Carlo Ratti; Geoffrey A. Block; Paul Muntner

BACKGROUND AND OBJECTIVES Calcification of the mitral and aortic valves is common in dialysis patients (CKD-5D). However, the prognostic significance of valvular calcification (VC) in CKD is not well established. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS 144 adult CKD-5D patients underwent bidimensional echocardiography for qualitative assessment of VC and cardiac computed tomography (CT) for quantification of coronary artery calcium (CAC) and VC. The patients were followed for a median of 5.6 years for mortality from all causes. RESULTS Overall, 38.2% of patients had mitral VC and 44.4% had aortic VC on echocardiography. Patients with VC were older and less likely to be African American; all other characteristics were similar between groups. The mortality rate of patients with calcification of either valve was higher than for patients without VC. After adjustment for age, gender, race, diabetes mellitus, and history of atherosclerotic disease, only mitral VC remained independently associated with all-cause mortality (hazard ratio [HR], 1.73; 95% confidence interval [CI], 1.03 to 2.91). Patients with calcification of both valves had a two-fold increased risk of death during follow-up compared with patients without VC (HR, 2.16; 95% CI, 1.14 to 4.08). A combined CT score of VC and CAC was strongly associated with all-cause mortality during follow-up (HR for highest versus lowest tertile, 2.21; 95% CI, 1.08 to 4.54). CONCLUSIONS VC is associated with a significantly increased risk for all-cause mortality in CKD-5D patients. These findings support the use of echocardiography for risk stratification in CKD-5D as recently suggested in the Kidney Disease Improving Global Outcomes guidelines.


The American Journal of the Medical Sciences | 2014

Statin Underuse and Low Prevalence of LDL-C Control Among U.S. Adults at High Risk of Coronary Heart Disease

Christopher Gamboa; Monika M. Safford; Emily B. Levitan; Devin M. Mann; Huifeng Yun; Stephen P. Glasser; J. Michael Woolley; Rosenson Robert; Michael E. Farkouh; Paul Muntner

Background:Statins reduce the risk of coronary heart disease (CHD) in individuals with a history of CHD or risk equivalents. A 10-year CHD risk >20% is considered a risk equivalent but is frequently not detected. Statin use and low-density lipoprotein cholesterol (LDL-C) control were examined among participants with CHD or risk equivalents in the nationwide Reasons for Geographic and Racial Differences in Stroke study (n = 8812). Methods:Participants were categorized into 4 mutually exclusive groups: (1) history of CHD (n = 4025); (2) no history of CHD but with a history of stroke and/or abdominal aortic aneurysm (AAA) (n = 946); (3) no history of CHD or stroke/AAA but with diabetes mellitus (n = 3134); or (4) no history of the conditions in (1) through (3) but with 10-year Framingham CHD risk score (FRS) >20% calculated using the third Adult Treatment Panel point scoring system (n = 707). Results:Statins were used by 58.4% of those in the CHD group and 41.7%, 40.4% and 20.1% of those in the stroke/AAA, diabetes mellitus and FRS >20% groups, respectively. Among those taking statins, 65.1% had LDL-C <100 mg/dL, with no difference between the CHD, stroke/AAA, or diabetes mellitus groups. However, compared with those in the CHD group, LDL-C <100 mg/dL was less common among participants in the FRS >20% group (multivariable adjusted prevalence ratio: 0.72; 95% confidence interval: 0.62–0.85). Results were similar using the 2013 American College of Cardiology/American Heart Association cholesterol treatment guideline. Conclusions:These data suggest that many people with high CHD risk, especially those with an FRS >20%, do not receive guideline-concordant lipid-lowering therapy and do not achieve an LDL-C <100 mg/dL.


Annals of Family Medicine | 2015

Peer Coaches to Improve Diabetes Outcomes in Rural Alabama: A Cluster Randomized Trial

Monika M. Safford; Susan J. Andreae; Andrea Cherrington; Michelle Y. Martin; Jewell H. Halanych; Marquita W. Lewis; Ashruta Patel; Ethel Johnson; Debra Clark; Christopher Gamboa; Joshua S. Richman

PURPOSE It is unclear whether peer coaching is effective in minority populations living with diabetes in hard-to-reach, under-resourced areas such as the rural South. We examined the effect of an innovative peer-coaching intervention plus brief education vs brief education alone on diabetes outcomes. METHODS This was a community-engaged, cluster-randomized, controlled trial with primary care practices and their surrounding communities serving as clusters. The trial enrolled 424 participants, with 360 completing baseline and follow-up data collection (84.9% retention). The primary outcomes were change in glycated hemoglobin (HbA1c), systolic blood pressure (BP), low density lipoprotein cholesterol (LDL-C), body mass index (BMI), and quality of life, with diabetes distress and patient activation as secondary outcomes. Peer coaches were trained for 2 days in community settings; the training emphasized motivational interviewing skills, diabetes basics, and goal setting. All participants received a 1-hour diabetes education class and a personalized diabetes report card at baseline. Intervention arm participants were also paired with peer coaches; the protocol called for telephone interactions weekly for the first 8 weeks, then monthly for a total of 10 months. RESULTS Due to real-world constraints, follow-up was protracted, and intervention effects varied over time. The analysis that included the 68% of participants followed up by 15 months showed only a significant increase in patient activation in the intervention group. The analysis that included all participants who eventually completed follow-up revealed that intervention arm participants had significant differences in changes in systolic BP (P = .047), BMI (P = .02), quality of life (P = .003), diabetes distress (P = .004), and patient activation (P = .03), but not in HbA1c (P = .14) or LDL-C (P = .97). CONCLUSION Telephone-delivered peer coaching holds promise to improve health for individuals with diabetes living in under-resourced areas.


American Journal of Preventive Medicine | 2015

Race–Sex Differences in the Management of Hyperlipidemia: The REasons for Geographic And Racial Differences in Stroke Study

Monika M. Safford; Christopher Gamboa; Raegan W. Durant; Todd M. Brown; Stephen P. Glasser; James M. Shikany; Richard M. Zweifler; George Howard; Paul Muntner

BACKGROUND Lipid management is less aggressive in blacks than whites and women than men. PURPOSE To examine whether differences in lipid management for race-sex groups compared to white men are due to factors influencing health services utilization or physician prescribing patterns. METHODS Because coronary heart disease (CHD) risk influences physician prescribing, Adult Treatment Panel III CHD risk categories were constructed using baseline data from REasons for Geographic And Racial Differences in Stroke study participants (recruited 2003-2007). Prevalence, awareness, treatment, and control of hyperlipidemia were examined for race-sex groups across CHD risk categories. Multivariable models conducted in 2013 estimated prevalence ratios adjusted for predisposing, enabling, and need factors influencing health services utilization. RESULTS The analytic sample included 7,809 WM; 7,712 white women; 4,096 black men; and 6,594 black women. Except in the lowest risk group, black men were less aware of hyperlipidemia than others. A higher percentage of white men in the highest risk group was treated (83.2%) and controlled (72.8%) than others (treatment, 68.6%-72.1%; control, 52.2%-65.5%), with black women treated and controlled the least. These differences remained significant after adjustment for predisposing, enabling, and need factors. Stratified analyses demonstrated that treatment and control were lower for other race-sex groups relative to white men only in the highest risk category. CONCLUSIONS Hyperlipidemia was more aggressively treated and controlled among white men compared with white women, black men, and especially black women among those at highest risk for CHD. These differences were not attributable to factors influencing health services utilization.


Journal of the American Heart Association | 2017

Comparison of Expert Adjudicated Coronary Heart Disease and Cardiovascular Disease Mortality With the National Death Index: Results From the REasons for Geographic And Racial Differences in Stroke (REGARDS) Study

Olusola Tope Olubowale; Monika M. Safford; Todd M. Brown; Raegan W. Durant; Virginia J. Howard; Christopher Gamboa; Stephen P. Glasser; J. David Rhodes; Emily B. Levitan

Background The National Death Index (NDI) is widely used to detect coronary heart disease (CHD) and cardiovascular disease (CVD) deaths, but its reliability has not been examined recently. Methods and Results We compared CHD and CVD deaths detected by NDI with expert adjudication of 4010 deaths that occurred between 2003 and 2013 among participants in the REGARDS (REasons for Geographic And Racial Differences in Stroke) cohort of black and white adults in the United States. NDI derived CHD mortality had sensitivity 53.6%, specificity 90.3%, positive predictive value 54.2%, and negative predictive value 90.1%. NDI‐derived CVD mortality had sensitivity 73.4%, specificity 84.5%, positive predictive value 70.6%, and negative predictive value 86.2%. Among NDI‐derived CHD and CVD deaths, older age (odds ratios, 1.06 and 1.04 per 1‐year increase) was associated with a higher probability of disagreement with the adjudicated cause of death, whereas among REGARDS adjudicated CHD and CVD deaths a history of CHD or CVD was associated with a lower probability of disagreement with the NDI‐derived causes of death (odds ratios, 0.59 and 0.67, respectively). Conclusions The modest accuracy and differential performance of NDI‐derived cause of death may impact CHD and CVD mortality statistics.


American Journal of Public Health | 2013

Association of Posttraumatic Stress Disorder and Depression With All-Cause and Cardiovascular Disease Mortality and Hospitalization Among Hurricane Katrina Survivors With End-Stage Renal Disease

Donald Edmondson; Christopher Gamboa; Andrew J. Cohen; Amanda H. Anderson; Nancy G. Kutner; Ian M. Kronish; Mary Alice Mills; Paul Muntner

OBJECTIVES We determined the association of psychiatric symptoms in the year after Hurricane Katrina with subsequent hospitalization and mortality in end-stage renal disease (ESRD) patients. METHODS A prospective cohort of ESRD patients (n = 391) treated at 9 hemodialysis centers in the New Orleans, Louisiana, area in the weeks before Hurricane Katrina were assessed for posttraumatic stress disorder (PTSD) and depression symptoms via telephone interview 9 to 15 months later. Two combined outcomes through August 2009 (maximum 3.5-year follow-up) were analyzed: (1) all-cause and (2) cardiovascular-related hospitalization and mortality. RESULTS Twenty-four percent of participants screened positive for PTSD and 46% for depression; 158 participants died (79 cardiovascular deaths), and 280 participants were hospitalized (167 for cardiovascular-related causes). Positive depression screening was associated with 33% higher risk of all-cause (hazard ratio [HR] = 1.33; 95% confidence interval [CI] = 1.06, 1.66) and cardiovascular-related hospitalization and mortality (HR = 1.33; 95% CI = 1.01, 1.76). PTSD was not significantly associated with either outcome. CONCLUSIONS Depression in the year after Hurricane Katrina was associated with increased risk of hospitalization and mortality in ESRD patients, underscoring the long-term consequences of natural disasters for vulnerable populations.


Health Promotion Practice | 2014

Assessing Peer Advisor Intervention Fidelity Using Video Skits in a Peer Support Implementation Trial

Marquita W. Lewis; Andrea Cherrington; Christopher Gamboa; Jewell H. Halanych; Michelle Y. Martin; Monika M. Safford

In community-based interventions involving lay health workers, or “community health workers,” peer–client interactions are not typically observed by investigators, creating challenges in assessing intervention fidelity. In the context of a community-based randomized controlled trial of the effectiveness of peer support on diabetes outcomes of people with diabetes in rural Alabama, a region characterized by poverty and low literacy, we developed a video assessment tool that assessed participant perceptions of peer–client interactions. The video assessment consisted of four short skits on areas of emphasis during peer training: directive versus nondirective counseling style and setting a specific versus a more general goal. The video tool was evaluated for association with questionnaire-derived measures of counseling style and goal setting among 102 participants. For counseling style, 44% of participants reported that their peer advisor was most similar to the nondirective skit. For goal setting, 42% reported that their peer advisor was most similar to the specific goal skit. There was no statistically significant relationship between skit selection and questionnaire-derived measures. The video assessment was feasible, but results suggest that video and questionnaire assessments in this population yield different results. Further validation to better understand the differences between questionnaire reports and video assessment is warranted.

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Monika M. Safford

University of Alabama at Birmingham

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Paul Muntner

University of Alabama at Birmingham

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Stephen P. Glasser

University of Alabama at Birmingham

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Emily B. Levitan

University of Alabama at Birmingham

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Todd M. Brown

University of Alabama at Birmingham

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Raegan W. Durant

University of Alabama at Birmingham

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George Howard

University of Alabama at Birmingham

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Joshua S. Richman

University of Alabama at Birmingham

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Virginia J. Howard

University of Alabama at Birmingham

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