Cognitive deficits and educational loss in children with schistosome infection-A systematic review and meta-analysis.

BACKGROUND: By means of meta-analysis of information from all relevant epidemiologic studies, we examined the hypothesis that Schistosoma infection in school-aged children (SAC) is associated with educational loss and cognitive deficits. METHODOLOGY/PRINCIPAL FINDINGS: This review was prospectively registered in the PROSPERO database (CRD42016040052). Medline, Biosis, and Web of Science were searched for studies published before August 2016 that evaluated associations between Schistosoma infection and cognitive or educational outcomes. Cognitive function was defined in four domains-learning, memory, reaction time, and innate intelligence. Educational outcome measures were defined as attendance and scholastic achievement. Risk of bias (ROB) was evaluated using the Newcastle-Ottawa quality assessment scale. Standardized mean differences (SMD) and 95% confidence intervals (CI) were calculated to compare cognitive and educational measures for Schistosoma infected /not dewormed vs. uninfected/dewormed children. Sensitivity analyses by study design, ROB, and sequential exclusion of individual studies were implemented. Thirty studies from 14 countries, including 38,992 SAC between 5-19 years old, were identified. Compared to uninfected children and children dewormed with praziquantel, the presence of Schistosoma infection and/or non-dewormed status was associated with deficits in school attendance (SMD = -0.36, 95%CI: -0.60, -0.12), scholastic achievement (SMD = -0.58, 95%CI: -0.96, -0.20), learning (SMD = -0.39, 95%CI: -0.70, -0.09) and memory (SMD = -0.28, 95%CI: -0.52, -0.04) tests. By contrast, Schistosoma-infected/non-dewormed and uninfected/dewormed children were similar with respect to performance in tests of reaction time (SMD = -0.06, 95%CI: -0.42, 0.30) and intelligence (SMD = -0.25, 95%CI: -0.57, 0.06). Schistosoma infection-associated deficits in educational measures were robust among observational studies, but not among interventional studies. The significance of infection-associated deficits in scholastic achievement was sensitive to ROB. Schistosoma infection-related deficits in learning and memory tests were invariant by ROB and study design. CONCLUSION/SIGNIFICANCE: Schistosoma infection/non-treatment was significantly associated with educational, learning, and memory deficits in SAC. Early treatment of children in Schistosoma-endemic regions could potentially mitigate these deficits. TRIAL REGISTRATION: ClinicalTrials.gov CRD42016040052

Longitudinal evaluation of aflatoxin exposure in two cohorts in south-western Uganda

Aflatoxins (AF) are a group of mycotoxins. AF exposure causes acute and chronic adverse health effects such as aflatoxicosis and hepatocellular carcinoma in human populations, especially in the developing world. In this study, AF exposure was evaluated using archived serum samples from human immunodeficiency virus (HIV)-seronegative participants from two cohort studies in south-western Uganda. AFB1-lysine (AFB-Lys) adduct levels were determined via HPLC fluorescence in a total of 713 serum samples from the General Population Cohort (GPC), covering eight time periods between 1989 and 2010. Overall, 90% (642/713) of the samples were positive for AFB-Lys and the median level was 1.58 pg mg(-1) albumin (range = 0.40-168 pg mg(-1) albumin). AFB-Lys adduct levels were also measured in a total of 374 serum samples from the Rakai Community Cohort Study (RCCS), across four time periods between 1999 and 2003. The averaged detection rate was 92.5% (346/374) and the median level was 1.18 pg mg(-1) albumin (range = 0.40-122.5 pg mg(-1) albumin). In the GPC study there were no statistically significant differences between demographic parameters, such as age, sex and level of education, and levels of serum AFB-Lys adduct. In the RCCS study, longitudinal analysis using generalised estimating equations revealed significant differences between the adduct levels and residential areas (p = 0.05) and occupations (p = 0.02). This study indicates that AF exposure in people in two populations in south-western Uganda is persistent and has not significantly changed over time. Data from one study, but not the other, indicated that agriculture workers and rural area residents had more AF exposure than those non-agricultural workers and non-rural area residents. These results suggest the need for further study of AF-induced human adverse health effects, especially the predominant diseases in the region

Flow diagram for search and selection of included studies.

<p>Flow diagram for search and selection of included studies.</p

Characteristics of 30 eligible studies of educational or cognitive loss in relation to <i>Schistosoma</i> species infection^a.

<p>Characteristics of 30 eligible studies of educational or cognitive loss in relation to <i>Schistosoma</i> species infection<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0005524#t001fn001" target="_blank">^a</a>.</p

Pooled estimate of <i>Schistosoma</i> infection or non-treatment on educational and cognitive loss in school-aged children from schistosomiasis-endemic regions: Stratified by study design, <i>Schistosoma</i> species, and study quality^a^,^b.

<p>Pooled estimate of <i>Schistosoma</i> infection or non-treatment on educational and cognitive loss in school-aged children from schistosomiasis-endemic regions: Stratified by study design, <i>Schistosoma</i> species, and study quality<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0005524#t004fn001" target="_blank">^a</a>^,<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0005524#t004fn002" target="_blank">^b</a>.</p

Pooled estimates of <i>Schistosoma</i> infection/non-treatment effects on educational/cognitive loss–Evaluation of heterogeneity and publication bias.

<p>Pooled estimates of <i>Schistosoma</i> infection/non-treatment effects on educational/cognitive loss–Evaluation of heterogeneity and publication bias.</p

Quality of evidence from individual studies included in the meta-analysis^a.

<p>Quality of evidence from individual studies included in the meta-analysis<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0005524#t003fn001" target="_blank">^a</a>.</p

Additional file 2: of Four Degrees of Separation: Social Contacts and Health Providers Influence the Steps to Final Diagnosis of Active Tuberculosis Patients in Urban Uganda

English questionnaire TB Steps. (PDF 28 kb