Ella T. Nkhoma

The global prevalence of glucose-6-phosphate dehydrogenase deficiency: a systematic review and meta-analysis.

Glucose-6-phosphate deficiency is the most prevalent enzyme deficiency, with an estimated 400 million people affected worldwide. This inherited deficiency causes neonatal hyperbilirubinemia and chronic hemolytic anemia. Although most affected individuals are asymptomatic, exposure to oxidative stressors such as certain drugs or infection, can elicit acute hemolysis. To characterize the global prevalence of G6PD deficiency, we conducted a systematic review of the G6PD deficiency literature, drawing studies from various databases, including MEDLINE/Pubmed and Biosis. Selected studies included cross-sectional and longitudinal studies published between 1960 and 2008. Additionally, meta-analytic procedures were employed to assess the degree of heterogeneity amongst prevalence estimates and, where appropriate, pool them. The searches yielded a total of 280 prevalence estimates, corresponding to 88 countries. The highest prevalence rates were reported among Sub-Saharan African countries, even after adjusting for assessment method. Meta-analysis revealed a high degree of heterogeneity for regional and global prevalence estimates. This heterogeneity in reported estimates appeared to be due to differences in G6PD deficiency assessment and diagnostic procedures. The magnitude and variation in global, regional, and country-level prevalence rates of G6PD deficiency are of public health import, particularly in planning programs to improve neonatal health and in the distribution of various medications, especially antimalarial drugs, as G6PD deficiency is most prevalent in malaria-endemic areas.

Detecting spatiotemporal clusters of accidental poisoning mortality among Texas counties, U.S., 1980 – 2001

BackgroundAccidental poisoning is one of the leading causes of injury in the United States, second only to motor vehicle accidents. According to the Centers for Disease Control and Prevention, the rates of accidental poisoning mortality have been increasing in the past fourteen years nationally. In Texas, mortality rates from accidental poisoning have mirrored national trends, increasing linearly from 1981 to 2001. The purpose of this study was to determine if there are spatiotemporal clusters of accidental poisoning mortality among Texas counties, and if so, whether there are variations in clustering and risk according to gender and race/ethnicity. The Spatial Scan Statistic in combination with GIS software was used to identify potential clusters between 1980 and 2001 among Texas counties, and Poisson regression was used to evaluate risk differences.ResultsSeveral significant (p < 0.05) accidental poisoning mortality clusters were identified in different regions of Texas. The geographic and temporal persistence of clusters was found to vary by racial group, gender, and race/gender combinations, and most of the clusters persisted into the present decade. Poisson regression revealed significant differences in risk according to race and gender. The Black population was found to be at greatest risk of accidental poisoning mortality relative to other race/ethnic groups (Relative Risk (RR) = 1.25, 95% Confidence Interval (CI) = 1.24 – 1.27), and the male population was found to be at elevated risk (RR = 2.47, 95% CI = 2.45 – 2.50) when the female population was used as a reference.ConclusionThe findings of the present study provide evidence for the existence of accidental poisoning mortality clusters in Texas, demonstrate the persistence of these clusters into the present decade, and show the spatiotemporal variations in risk and clustering of accidental poisoning deaths by gender and race/ethnicity. By quantifying disparities in accidental poisoning mortality by place, time and person, this study demonstrates the utility of the spatial scan statistic combined with GIS and regression methods in identifying priority areas for public health planning and resource allocation.

Promotores de Salud: Educating Hispanic Communities on Heart-Healthy Living.

Abstract Background: Age-adjusted cardiovascular disease (CVD) mortality rates for Hispanics are lower than for non-Hispanics. However, CVD is the leading cause of death among Hispanics, and there is an increasing heart health problem among this population. One strategy for preventing CVD is the use of community health workers (CHWs). A CHW is a member of the community who disseminates information, attempts to foster healthy behavior, and provides education, advice, social support, and assistance to the community. Although the efficacy of CHWs has been tested, few studies have examined their effectiveness in educating communities and facilitating behavior change. Purpose: This study explored whether trained CHWs can effectively deliver education on heart-healthy behaviors among Hispanics. Methods: Two group of participants received education programs delivered by CHWs, popularly known in the Hispanic community as promotores de salud. A pretest/post-test design was implemented to assess intervention effect. Analyses included sample t-test, chi-square (χ2), and Mann-Whitney U Test. Results: The two groups differed in demographics and pre-existing risk factors (p<.05). Participants in both groups significantly improved their healthy behaviors (p<.01). Discussion: Observed improvement in healthy behaviors in both participant groups strengthens the argument that the community health outreach promotores model may be effective and can be adapted to a variety of settings. Translation to Health Education Practice: The results of this study support the utilization of CHWs.

Prevalence, severity, and duration of thrombocytopenia among HIV patients in the era of highly active antiretroviral therapy

Thrombocytopenia is a clinically relevant outcome in HIV. However, the epidemiology of this condition, including frequency, severity, and duration, has not been well-characterized in the era of highly active antiretroviral therapy (HAART). In this study, we describe the epidemiology of thrombocytopenia using two methods. We conducted a systematic review of the literature published between 1997 and 2009 to characterize the frequency of thrombocytopenia in different populations in the HAART era. Secondly, we examined the frequency, severity, and duration of thrombocytopenia among HIV patients in the Collaborations in HIV Outcomes Research/US (CHORUS) Cohort from 1997 to 2006 and among HIV patients participating in GlaxoSmithKline HIV Clinical Trials between 1996 and 2004. Prevalence estimates of thrombocytopenia (<150 000 platelets/µl) in the literature varied greatly but were generally above 10%. The thrombocytopenia prevalence estimates in the CHORUS Cohort and the HIV Clinical Trials were both 14%. In the CHORUS Cohort, the platelet count was ≤50 000/µl among 3.1% and ≤30 000/µl among 1.7%; in the HIV clinical trials database, the platelet count was ≤50 000/µl among 1.3% and ≤30 000/µl among 0.67%. Duration of severe thrombocytopenia varied greatly, with the medium duration to ≥75 000 platelets/µl taking 147 days in the CHORUS Cohort and 33 days in the HIV clinical trials database. Among 111 patients with severe thrombocytopenia in the CHORUS Cohort, 23% never achieved a higher platelet count over follow-up. In conclusion, while the prevalence of severe thrombocytopenia was low, it occurred at levels associated with bleeding and was persistent among a small proportion of patients despite receipt of HAART.

Effect of HIV Infection and Plasmodium falciparum Parasitemia on Pregnancy Outcomes in Malawi

Plasmodium falciparum and human immunodeficiency virus (HIV) are both risk factors for low birth weight (LBW) and maternal anemia, and they may interact to increase risk of adverse pregnancy outcomes. In 2005 and 2006, we followed 831 pregnant women attending antenatal care clinics in southern Malawi through delivery. HIV was associated with increased risk of LBW (adjusted prevalence ratio [PR(adj)] = 3.08, 95% confidence interval [CI] = 1.40, 6.79). Having greater than or equal to three episodes of peripheral parasitemia was also associated with increased risk of LBW (PR(adj) = 2.68, 95% CI = 1.06, 6.79). Among multigravidae, dual infection resulted in 9.59 (95% CI = 2.51, 36.6) times the risk of LBW compared with uninfected multigravidae. HIV infection and placental parasitemia were each associated with increased risk of anemia. Thus, HIV infection and parasitemia are important independent risk factors for adverse pregnancy outcomes. Among multigravidae, HIV infection and placental parasitemia may interact to produce an impact greater than the sum of their independent effects.

Examining Geographic and Temporal Variations of AIDS Mortality: Evidence of Racial Disparities

BACKGROUND There is little literature on spatiotemporal trends of AIDS mortality among different race and gender groups. The purpose of the present study is to describe AIDS mortality geographically and temporally, and to determine if detected trends vary by race and gender. METHODS The Spatial Scan Statistic was employed to examine the geographic excess of AIDS mortality by race and gender in 24 Maryland jurisdictions between 1987 and 2003. Spatial analysis was conducted to identify clusters of excess mortality. The temporal scan statistic was used to explore time trends of AIDS mortality. Prospective space-time analysis was also conducted to verify if detected clusters persisted into the present. RESULTS Among 10,887 AIDS deaths, 77.5% occurred in African Americans. Geographic excesses of AIDS mortality were detected in Baltimore city, and Howard, Montgomery, Anne Arundel, Prince Georges and Baltimore counties. Over the study period, AIDS mortality peaked in 1995 and then sharply dropped until 1998, when it stabilized. However, the AIDS mortality of African-American women started oscillating upward in 1998. CONCLUSION This study quantitatively described geographic and temporal variations of AIDS mortality in Maryland by gender and racial groups. The results may inform development of programs to address HIV/AIDS while considering the groups most affected differentially by geographic area.

The Effect of HIV Infection on the Risk, Frequency, and Intensity of Plasmodium falciparum Parasitemia in Primigravid and Multigravid Women in Malawi

Human immunodeficiency virus (HIV) is common in pregnant women in many malaria-endemic regions and may increase risk of placental parasitemia. Placental malaria is more common in primigravidae than multigravidae, but the relationship between HIV and malaria across gravidities is not well characterized. We recruited pregnant Malawian women during the second trimester and followed them until delivery. Parasitemia was assessed at enrollment, follow-up visits, and delivery, when placental blood was sampled. There was no difference in risk of parasitemia between HIV-positive and HIV-negative primigravidae. Among multigravidae, HIV-infected women had greater than twice the risk of parasitemia as HIV-uninfected women throughout follow-up. Human immunodeficiency virus was also associated with more frequent peripheral parasitemia in multigravidae but not primigravidae. Both HIV and primigravid status were independently associated with higher peripheral and placental parasite densities. Although risk of parasitemia is lower in multigravidae than primigravidae, the HIV effect on risk of malaria is more pronounced in multigravidae.

A New Application of Spatiotemporal Analysis for Detecting Demographic Variations in AIDS Mortality: An Example from Florida

The purpose of the present study was to characterize, geographically and temporally, the patterns of acquired immune deficiency syndrome (AIDS) death disparity in 67 Florida jurisdictions, and to determine if the detected trends varied according to age, race, and sex. The space‐time scan statistic proposed by Kulldorff et al was used to examine the excess AIDS deaths that occurred between 1987 and 2004. Results were geographically referenced in maps using EpiInfo and EpiMap made available by the Centers for Disease Control. Miami‐Dade and the nearby counties including Broward, Martin, and Palm Beach are the most likely clusters (observed/expected: 1505.16) with temporal dimension (also called clusters age) persisting from 1996 to the present. Union county had the longest cluster for the cluster period 1987–1998, but not for 1999–2004. African‐Americans contributed to more clusters compared with whites. Time trends indicated that AIDS mortality peaked in 1995 and then sharply dropped until 1998, when the decrease stopped. By accounting for the temporal dimension of disease clustering, the present study revealed the persistence of geographic clusters, which is not often provided by other geographic detection methods. These findings may be informative for medical resource allocation and better focus public health intervention strategies for AIDS care.