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Featured researches published by David Martins.


Journal of General Internal Medicine | 2009

The Association of Stigma with Self-Reported Access to Medical Care and Antiretroviral Therapy Adherence in Persons Living with HIV/AIDS

Jennifer N. Sayles; Mitchell D. Wong; Janni J. Kinsler; David Martins; William E. Cunningham

BackgroundThe stigma of HIV-infection may profoundly affect the lives of persons living with HIV/AIDS (PLHA). However few studies have examined the association of HIV stigma with multiple components of HIV treatment and care.ObjectivesTo estimate the association between HIV stigma and: self-reported access to care, regular source of HIV care, and antiretroviral therapy adherence; and to test whether mental health mediates these associations. DesignCross-sectional study.Participants202 PLHA living in Los Angeles County in 2007.MeasurementsParticipants completed an anonymous survey, assessing internalized HIV stigma (28-items, alpha = 0.93), self-reported access to medical care (six items, alpha = 0.75), regular source of HIV care, and antiretroviral therapy (ART) adherence.ResultsOne-third of participants reported high levels of stigma; 77% reported poor access to care; 42.5% reported suboptimal ART adherence; and 10.5% reported no regular source of HIV care. In unadjusted analysis, those reporting a high level of stigma were more likely to report poor access to care (OR = 4.97, 95% CI 2.54–9.72), regular source of HIV care (OR = 2.48, 95% CI 1.00–6.19), and ART adherence (OR = 2.45, 95% CI 1.23–4.91). In adjusted analyses, stigma was significantly associated with poor access to care (OR = 4.42, 95% CI 1.88–10.37), but not regular source of HIV care or ART adherence. Mental health mediated the relationship between stigma and ART adherence, but not poor access to care or regular source of HIV care.ConclusionsThe association of stigma with self-reported access to care and adherence suggests that efforts to improve these components of HIV care will require a better understanding of the possible effects of stigma and it′s mediators.


Kidney International | 2009

Chronic kidney disease, hypovitaminosis D, and mortality in the United States.

Rajnish Mehrotra; Dulcie Kermah; Isidro B. Salusky; Myles Wolf; Ravi Thadhani; Yi Wen Chiu; David Martins; Sharon G. Adler; Keith C. Norris

Low serum 25-hydroxy vitamin D (25OHD) predicts a higher cardiovascular risk in the general population. Because patients with chronic kidney disease are more likely to have low serum 25OHD, we determined the relationship between hypovitaminosis D and death in this group. Analysis was done using a cohort composed of 3011 patients from the Third National Health and Nutrition Examination Survey who had chronic kidney disease but were not on dialysis and who had a mean follow-up of 9 years. In analyses adjusted for demographics, cardiovascular risk factors, serum phosphorus, albumin, hemoglobin, stage of chronic kidney disease, albuminuria, and socioeconomic status, individuals with serum 25OHD levels less than 15 ng/ml had an increased risk for all-cause mortality when compared to those with levels over 30 ng/ml. This significantly higher risk for death with low serum 25OHD was evident in 15 of the 23 subgroups. The higher risk for cardiovascular and non-cardiovascular mortality became statistically nonsignificant on multivariable adjustment. The trend for higher mortality in patients with 25OHD levels 15-30 ng/ml was not statistically significant. Our results indicate there is a graded relationship between serum 25OHD and the risk for death among subjects with chronic kidney disease who are not undergoing dialysis. Randomized, controlled trials are needed to conclusively determine whether vitamin D supplementation reduces mortality.


The American Journal of the Medical Sciences | 2002

The epidemiology of end-stage renal disease among African Americans.

David Martins; Naureen Tareen; Keith C. Norris

Although disparities in outcomes among African Americans compared with whites with respect to cardiovascular disease, cancer, diabetes, infant mortality, and other health standards have been well-described, these disparities are most dramatic with respect to kidney diseases. End-stage renal disease (ESRD) occurs almost 4 times more commonly in African Americans than in their white counterparts. These disparate rates of kidney disease may be caused by the complex interplay of genetic, environmental, cultural, and socioeconomic factors. African Americans are particularly vulnerable to the deleterious renal effects of hypertension and may require more aggressive blood pressure control than whites to accrue benefit with respect to preservation of renal function. Diabetes, the leading cause of ESRD in the United States, is another important factor in the excess renal morbidity and mortality of African Americans because of its prevalence in this population. Other renal diseases, especially those associated with HIV/AIDS, are also much more likely to affect African Americans than other American population subgroups. A more thorough understanding of the epidemiology of renal diseases in African Americans and the cultural, social, and biological differences that underlie racial disparities in prevalence of renal disease will be essential to the design of effective public health strategies for prevention and treatment of this burdensome problem.


Public Health Nutrition | 2009

Overweight and obesity among Ghanaian residents in The Netherlands: how do they weigh against their urban and rural counterparts in Ghana?

Charles Agyemang; Ellis Owusu-Dabo; Ank de Jonge; David Martins; Gbenga Ogedegbe; Karien Stronks

OBJECTIVE To investigate differences in overweight and obesity between first-generation Dutch-Ghanaian migrants in The Netherlands and their rural and urban counterparts in Ghana. DESIGN Cross-sectional study. SUBJECTS A total of 1471 Ghanaians (rural Ghanaians, n 532; urban Ghanaians, n 787; Dutch-Ghanaians, n 152) aged > or = 17 years. MAIN OUTCOME MEASURES Overweight (BMI > or = 25 kg/m2) and obesity (BMI > or = 30 kg/m2). RESULTS Dutch-Ghanaians had a significantly higher prevalence of overweight and obesity (men 69.1%, women 79.5%) than urban Ghanaians (men 22.0%, women 50.0%) and rural Ghanaians (men 10.3%, women 19.0%). Urban Ghanaian men and women also had a significantly higher prevalence of overweight and obesity than their rural Ghanaian counterparts. In a logistic regression analysis adjusting for age and education, the odds ratios for being overweight or obese were 3.10 (95% CI 1.75, 5.48) for urban Ghanaian men and 19.06 (95% CI 8.98, 40.43) for Dutch-Ghanaian men compared with rural Ghanaian men. Among women, the odds ratios for being overweight and obese were 3.84 (95% CI 2.66, 5.53) for urban Ghanaians and 11.4 (95% CI 5.97, 22.07) for Dutch-Ghanaians compared with their rural Ghanaian counterparts. CONCLUSION Our current findings give credence to earlier reports of an increase in the prevalence of overweight/obesity with urbanization within Africa and migration to industrialized countries. These findings indicate an urgent need to further assess migration-related factors that lead to these increases in overweight and obesity among migrants with non-Western background, and their impact on overweight- and obesity-related illnesses such as diabetes among these populations.


Journal of The National Medical Association | 2008

The relative risk of cardiovascular death among racial and ethnic minorities with metabolic syndrome: data from the NHANES-II mortality follow-up.

David Martins; Naureen Tareen; Godwin Ogedegbe; Deyu Pan; Keith C. Norris

The tendency for selected cardiovascular disease (CVD) risk factors to occur in clusters has led to the description of metabolic syndrome (MetS). The relative impact of the individual risk factor on the overall relative risk (RR) for cardiovascular death from metabolic syndrome is not well established and may differ across the different racial/ethnic groups. Using data from the National Health and Nutrition Examination Survey (NHANES II) mortality follow-up (NH2MS), we determined the prevalence and RR of cardiovascular death for individual components in the overall population and across racial and ethnic groups. The prevalence of MetS components varied significantly across gender and racial/ethnic groupings. The RR for CVD also varies for the number and different components of MetS. The adjusted RR for cardiovascular death was highest with diabetes (3.23; 95% CI: 2.70-3.88), elevated blood pressure (2.28; 95% CI: 1.94-2.67) and high triglycerides (1.63; 95% CI: 1.34-2.00). Although the RR for cardiovascular death differs significantly for some of the different components, the overall findings were similar across racial/ethnic groups. The two components that confer the highest risks for death are more prevalent in African Americans. We concluded that the RR of cardiovascular death associated with the diagnosis of MetS varies depending on the number and components used to establish the diagnosis of MetS and the racial/ethnic characteristic of the participants.


Journal of Health Care for the Poor and Underserved | 2011

Vitamin D and Cardiovascular Disease: Potential Role in Health Disparities

Jorge N. Artaza; Sandra Contreras; Leah A. Garcia; Rajnish Mehrotra; Gary H. Gibbons; Ralph V. Shohet; David Martins; Keith C. Norris

Cardiovascular disease (CVD), which includes coronary artery disease and stroke, is the leading cause of mortality in the nation. Excess CVD morbidity and premature mortality in the African American community is one of the most striking examples of racial/ ethnic disparities in health outcomes. African Americans also suffer from increased rates of hypovitaminosis D, which has emerged as an independent risk factor for all-cause and cardiovascular mortality. This overview examines the potential role of hypovitaminosis D as a contributor to racial and ethnic disparities in cardiovascular disease (CVD). We review the epidemiology of vitamin D and CVD in African Americans and the emerging biological roles of vitamin D in key CVD signaling pathways that may contribute to the epidemiological findings and provide the foundation for future therapeutic strategies for reducing health disparities.


Journal of Nutrition and Metabolism | 2010

Renal Dysfunction, Metabolic Syndrome and Cardiovascular Disease Mortality

David Martins; Chizobam Ani; Deyu Pan; Omolola Ogunyemi; Keith C. Norris

Background. Renal disease is commonly described as a complication of metabolic syndrome (MetS) but some recent studies suggest that Chronic Kidney disease (CKD) may actually antecede MetS. Few studies have explored the predictive utility of co-clustering CKD with MetS for cardiovascular disease (CVD) mortality. Methods. Data from a nationally representative sample of United States adults (NHANES) was utilized. A sample of 13115 non-pregnant individuals aged ≥35 years, with available follow-up mortality assessment was selected. Multivariable Cox Proportional hazard regression analysis techniques explored the relationship between co-clustered CKD, MetS and CVD mortality. Bayesian analysis techniques tested the predictive accuracy for CVD Mortality of two models using co-clustered MetS and CKD and MetS alone. Results. Co-clustering early and late CKD respectively resulted in statistically significant higher hazard for CVD mortality (HR = 1.80, CI = 1.45–2.23, and HR = 3.23, CI = 2.56–3.70) when compared with individuals with no MetS and no CKD. A model with early CKD and MetS has a higher predictive accuracy (72.0% versus 67.6%), area under the ROC (0.74 versus 0.66), and Cohens kappa (0.38 versus 0.21) than that with MetS alone. Conclusion. The study findings suggest that the co-clustering of early CKD with MetS increases the accuracy of risk prediction for CVD mortality.


Journal of Insect Science | 2008

Diaspididae (Hemiptera: Coccoidea) of Espírito Santo, Brazil

Mark P. Culik; David Martins; José Aires Ventura; Vera R. S. Wolff

Abstract Twenty-seven species of armored scale insects (Hemiptera: Diaspididae) are newly recorded from Espírito Santo, Brazil, and information on the host plants and geographic distribution of the 31 species of Diaspididae that have been identified in the State is provided. New plant host records are reported for 11 of the diaspidid species studied and results are discussed with respect to development of agriculture in this and similar areas with objectives of modernization and diversification.


American Journal of Hypertension | 2001

The relationship between body mass index and pulse pressure in older adults with isolated systolic hypertension

David Martins; Naureen Tareen; Deyu Pan; Keith C. Norris

BACKGROUND Many longitudinal studies have reported excess cardiovascular mortality among lean hypertensive subjects, suggesting that obesity may mitigate the cardiovascular risk of hypertension. Available evidence also suggests that in middle-aged and older hypertensive subjects, pulse pressure may be a better predictor of cardiovascular complications. However, there are limited data on the relationship between body mass index (BMI) and pulse pressure. METHODS Using data from the Third National Health and Nutrition Examination Survey we assessed the convergence validity of pulse pressure as a predictor of cardiovascular complications and examined the relationship between BMI and pulse pressure in 1192 older adults with isolated systolic hypertension who were not receiving blood pressure medicine. RESULTS There was a good concordance between high pulse pressure and most of the selected cardiovascular risk factors examined in this study. Pulse pressure is higher in the lean (BMI < 25) than in the overweight (BMI > or = 25; 79 mm Hg vs 74 mm Hg, P < .001) and decreases significantly from 82 mm Hg in the first BMI quintile to 76 mm Hg in the fifth BMI quintile. Pulse pressure continues to decrease with increasing BMI until the index exceeds 30.1. This negative correlation persists in a multivariate model with statistical adjustment for age, sex, diabetes mellitus, and hypercholesterolemia. CONCLUSION The inverse relation between BMI and pulse pressure observed here may help to explain previous reports of increased cardiovascular risk among lean versus obese subjects with isolated systolic hypertension.


Health | 2014

The Effect of Short Term Vitamin D Supplementation on the Inflammatory and Oxidative Mediators of Arterial Stiffness

David Martins; Yuan-Xiang Meng; Naureen Tareen; Jorge N. Artaza; Jae Eun Lee; Caroline Farodolu; Gary H. Gibbons; Keith C. Norris

Background Vitamin D deficiency has been implicated as a potential risk factor for cardiovascular disease. The high rate of vitamin D deficiency (<30 ng/ml) exhibited by African Americans may account for some of the excess prevalence of cardiovascular morbidity and mortality in this vulnerable US population. Vitamin D supplementation may reduce the risk of cardiovascular disease by ameliorating the onset and progression of arterial stiffness, a strong predictor of cardiovascular mortality, usually assessed by pulse wave velocity and augmentation index. Very few prospective studies have evaluated the effect of vitamin D supplementation on the inflammatory and oxidative stress mediators of arterial stiffness. Method In a double blind randomized placebo controlled study we evaluated the effect of a monthly dose of 100,000IU of vitamin D3 for three months on the level of serum 25(OH)D, intact parathyroid hormone (PTH), urinary isoprostane, adipocyte cytokine expression and arterial stiffness among 130 overweight and obese (BMI > 25) African Americans with elevated blood pressure (130 - 150/85 - 100 mmHg) and low serum vitamin D level (10 - 25 ng/ml). Results There was a significant increase in the serum 25(OH)D levels to a mean level of 34.5 ng/ml (SD = 7.1) with the intervention (p < 0.001). The increase in 25(OH)D levels was associated with a significant decrease in the serum level of intact PTH (p = 0.02), mean urinary isoprostane (p = 0.02) and adipocyte cytokine expression. Although the increase in the 25(OH)D levels was not associated with any significant change in the Pulse Wave Velocity (PWV) in the overall study sample, it was associated with a significant decrease in the augmentation index among the participants with the highest tertile of urinary isoprostane (p = 0.007). Conclusion We concluded that vitamin D supplementation increased serum 25(OH)D levels, decreased intact PTH level and the levels of select inflammatory and oxidative stress mediators of arterial stiffness. Longer term prospective studies are warranted to evaluate the effect of high dose vitamin D supplementation on arterial stiffness.

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Mark P. Culik

Universidade Federal de Viçosa

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Naureen Tareen

Charles R. Drew University of Medicine and Science

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Deyu Pan

Charles R. Drew University of Medicine and Science

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José Aires Ventura

Universidade Federal do Espírito Santo

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Ashraf Zadshir

Charles R. Drew University of Medicine and Science

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José Cola Zanuncio

Universidade Federal de Viçosa

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