Joshua V. Garn

Association of Biochemical B12 Deficiency With Metformin Therapy and Vitamin B12 Supplements The National Health and Nutrition Examination Survey, 1999–2006

OBJECTIVE To describe the prevalence of biochemical B12 deficiency in adults with type 2 diabetes taking metformin compared with those not taking metformin and those without diabetes, and explore whether this relationship is modified by vitamin B12 supplements. RESEARCH DESIGN AND METHODS Analysis of data on U.S. adults ≥50 years of age with (n = 1,621) or without type 2 diabetes (n = 6,867) from the National Health and Nutrition Examination Survey (NHANES), 1999–2006. Type 2 diabetes was defined as clinical diagnosis after age 30 without initiation of insulin therapy within 1 year. Those with diabetes were classified according to their current metformin use. Biochemical B12 deficiency was defined as serum B12 concentrations ≤148 pmol/L and borderline deficiency was defined as >148 to ≤221 pmol/L. RESULTS Biochemical B12 deficiency was present in 5.8% of those with diabetes using metformin compared with 2.4% of those not using metformin (P = 0.0026) and 3.3% of those without diabetes (P = 0.0002). Among those with diabetes, metformin use was associated with biochemical B12 deficiency (adjusted odds ratio 2.92; 95% CI 1.26–6.78). Consumption of any supplement containing B12 was not associated with a reduction in the prevalence of biochemical B12 deficiency among those with diabetes, whereas consumption of any supplement containing B12 was associated with a two-thirds reduction among those without diabetes. CONCLUSIONS Metformin therapy is associated with a higher prevalence of biochemical B12 deficiency. The amount of B12 recommended by the Institute of Medicine (IOM) (2.4 μg/day) and the amount available in general multivitamins (6 μg) may not be enough to correct this deficiency among those with diabetes.OBJECTIVE To describe the prevalence of biochemical B(12) deficiency in adults with type 2 diabetes taking metformin compared with those not taking metformin and those without diabetes, and explore whether this relationship is modified by vitamin B(12) supplements. RESEARCH DESIGN AND METHODS Analysis of data on U.S. adults ≥50 years of age with (n = 1,621) or without type 2 diabetes (n = 6,867) from the National Health and Nutrition Examination Survey (NHANES), 1999-2006. Type 2 diabetes was defined as clinical diagnosis after age 30 without initiation of insulin therapy within 1 year. Those with diabetes were classified according to their current metformin use. Biochemical B(12) deficiency was defined as serum B(12) concentrations ≤148 pmol/L and borderline deficiency was defined as >148 to ≤221 pmol/L. RESULTS Biochemical B(12) deficiency was present in 5.8% of those with diabetes using metformin compared with 2.4% of those not using metformin (P = 0.0026) and 3.3% of those without diabetes (P = 0.0002). Among those with diabetes, metformin use was associated with biochemical B(12) deficiency (adjusted odds ratio 2.92; 95% CI 1.26-6.78). Consumption of any supplement containing B(12) was not associated with a reduction in the prevalence of biochemical B(12) deficiency among those with diabetes, whereas consumption of any supplement containing B(12) was associated with a two-thirds reduction among those without diabetes. CONCLUSIONS Metformin therapy is associated with a higher prevalence of biochemical B(12) deficiency. The amount of B(12) recommended by the Institute of Medicine (IOM) (2.4 μg/day) and the amount available in general multivitamins (6 μg) may not be enough to correct this deficiency among those with diabetes.

The impact of sanitation interventions on latrine coverage and latrine use: A systematic review and meta-analysis

Background An estimated 2.4 billion people still lack access to improved sanitation and 946 million still practice open defecation. The World Health Organization (WHO) commissioned this review to assess the impact of sanitation on coverage and use, as part of its effort to develop a set of guidelines on sanitation and health. Methods and findings We systematically reviewed the literature and used meta-analysis to quantitatively characterize how different sanitation interventions impact latrine coverage and use. We also assessed both qualitative and quantitative studies to understand how different structural and design characteristics of sanitation are associated with individual latrine use. A total of 64 studies met our eligibility criteria. Of 27 intervention studies that reported on household latrine coverage and provided a point estimate with confidence interval, the average increase in coverage was 14% (95% CI: 10%, 19%). The intervention types with the largest absolute increases in coverage included the Indian governments “Total Sanitation Campaign” (27%; 95% CI: 14%, 39%), latrine subsidy/provision interventions (16%; 95% CI: 8%, 24%), latrine subsidy/provision interventions that also incorporated education components (17%; 95% CI: −5%, 38%), sewerage interventions (14%; 95% CI: 1%, 28%), sanitation education interventions (14%; 95% CI: 3%, 26%), and community-led total sanitation interventions (12%; 95% CI: −2%, 27%). Of 10 intervention studies that reported on household latrine use, the average increase was 13% (95% CI: 4%, 21%). The sanitation interventions and contexts in which they were implemented varied, leading to high heterogeneity across studies. We found 24 studies that examined the association between structural and design characteristics of sanitation facilities and facility use. These studies reported that better maintenance, accessibility, privacy, facility type, cleanliness, newer latrines, and better hygiene access were all frequently associated with higher use, whereas poorer sanitation conditions were associated with lower use. Conclusions Our results indicate that most sanitation interventions only had a modest impact on increasing latrine coverage and use. A further understanding of how different sanitation characteristics and sanitation interventions impact coverage and use is essential in order to more effectively attain sanitation access for all, eliminate open defecation, and ultimately improve health.

Associations between school- and household-level water, sanitation and hygiene conditions and soil-transmitted helminth infection among Kenyan school children

BackgroundSoil-transmitted helminths, a class of parasitic intestinal worms, are pervasive in many low-income settings. Infection among children can lead to poor nutritional outcomes, anaemia, and reduced cognition. Mass treatment, typically administered through schools, with yearly or biannual drugs is inexpensive and can reduce worm burden, but reinfection can occur rapidly. Access to and use of sanitation facilities and proper hygiene can reduce infection, but rigorous data are scarce. Among school-age children, infection can occur at home or at school, but little is known about the relative importance of WASH in transmission in these two settings.MethodsWe explored the relationships between school and household water, sanitation, and hygiene conditions and behaviours during the baseline of a large-scale mass drug administration programme in Kenya. We assessed several WASH measures to quantify the exposure of school children, and developed theory and empirically-based parsimonious models.ResultsResults suggest mixed impacts of household and school WASH on prevalence and intensity of infection. WASH risk factors differed across individual worm species, which is expected given the different mechanisms of infection.ConclusionsNo trend of the relative importance of school versus household-level WASH emerged, though some factors, like water supply were more strongly related to lower infection, which suggests it is important in supporting other school practices, such as hand-washing and keeping school toilets clean.

The impact of sanitation on infectious disease and nutritional status: A systematic review and meta-analysis.

BACKGROUND Sanitation aims to sequester human feces and prevent exposure to fecal pathogens. More than 2.4 billion people worldwide lack access to improved sanitation facilities and almost one billion practice open defecation. We undertook systematic reviews and meta-analyses to compile the most recent evidence on the impact of sanitation on diarrhea, soil-transmitted helminth (STH) infections, trachoma, schistosomiasis, and nutritional status assessed using anthropometry. METHODS AND FINDINGS We updated previously published reviews by following their search strategy and eligibility criteria. We searched from the previous reviews end date to December 31, 2015. We conducted meta-analyses to estimate pooled measures of effect using random-effects models and conducted subgroup analyses to assess impact of different levels of sanitation services and to explore sources of heterogeneity. We assessed risk of bias and quality of the evidence from intervention studies using the Liverpool Quality Appraisal Tool (LQAT) and Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach, respectively. A total of 171 studies met the reviews inclusion criteria, including 64 studies not included in the previous reviews. Overall, the evidence suggests that sanitation is protective against diarrhea, active trachoma, some STH infections, schistosomiasis, and height-for-age, with no protective effect for other anthropometric outcomes. The evidence was generally of poor quality, heterogeneity was high, and GRADE scores ranged from very low to high. CONCLUSIONS This review confirms positive impacts of sanitation on aspects of health. Evidence gaps remain and point to the need for research that rigorously describes sanitation implementation and type of sanitation interventions.

Assessing The Impact Of A School-Based Latrine Cleaning And Handwashing Program On Pupil Absence In Nyanza Province, Kenya: A Cluster-Randomized Trial

Improving school water, sanitation and hygiene (WASH) conditions reduces pupil absence and illness. However, these benefits may depend on the conditions of the latrines and availability of consumables. We sought to determine whether a low‐cost, policy‐relevant, environmental‐level latrine cleaning intervention could improve latrine cleanliness, increase its use and reduce absenteeism.

The Impact of a School-Based Water, Sanitation, and Hygiene Program on Absenteeism, Diarrhea, and Respiratory Infection: A Matched–Control Trial in Mali

We conducted a matched-control trial in Mali to assess the effectiveness of a comprehensive school-based water, sanitation, and hygiene (WASH) intervention on pupil absence, diarrhea, and respiratory infections. After completion of the intervention, data were collected from 100 beneficiary schools and 100 matched comparison schools in 5-6 sessions over a 14-month period. Data collection included roll calls to assess absenteeism and interviews with a subset of pupils to assess recent absence and disease symptoms. The odds of pupils being absent at roll call were 23% higher in beneficiary schools than in comparison schools (odds ratio [OR]: 1.23, 95% confidence interval [CI]: 1.06, 1.42). The odds of pupils reporting being absent due to diarrhea (OR: 0.73, 95% CI: 0.56, 0.94) or having had diarrhea (OR: 0.71, 95% CI: 0.60, 0.85) or respiratory infection symptoms (OR: 0.75, 95% CI: 0.65, 0.86) in the past week were lower in beneficiary schools compared with comparison schools. We found that a school-based WASH intervention can have a positive effect on reducing rates of illness, as well as absence due to diarrhea. However, we did not find evidence that these health impacts led to a reduction in overall absence. Higher absence rates are less likely attributable to the intervention than the result of an imbalance in unobserved confounders between study groups.

Factors associated with pupil toilet use in kenyan primary schools.

The purpose of this study was to quantify how school sanitation conditions are associated with pupils’ use of sanitation facilities. We conducted a longitudinal assessment in 60 primary schools in Nyanza Province, Kenya, using structured observations to measure facility conditions and pupils’ use at specific facilities. We used multivariable mixed regression models to characterize how pupil to toilet ratio was associated with toilet use at the school-level and also how facility conditions were associated with pupils’ use at specific facilities. We found a piecewise linear relationship between decreasing pupil to toilet ratio and increasing pupil toilet use (p < 0.01). Our data also revealed significant associations between toilet use and newer facility age (p < 0.01), facility type (p < 0.01), and the number of toilets in a facility (p < 0.01). We found some evidence suggesting facility dirtiness may deter girls from use (p = 0.06), but not boys (p = 0.98). Our study is the first to rigorously quantify many of these relationships, and provides insight into the complexity of factors affecting pupil toilet use patterns, potentially leading to a better allocation of resources for school sanitation, and to improved health and educational outcomes for children.

Assessing the impact of sanitation on indicators of fecal exposure along principal transmission pathways: A systematic review.

OBJECTIVE Fecal-oral transmission of enteric and other pathogens due to poor sanitation is a major cause of morbidity and mortality, especially in low- or middle-income settings. Few studies have investigated the impact of sanitation on indicators of transmission, a prerequisite to achieving health gains. This review attempts to summarize the literature to date. METHODS We searched leading databases to identify studies that address the effect of sanitation on various transmission pathways including fecal pathogens or indicator bacteria in drinking water, hand contamination, sentinel toys, food, household and latrine surfaces and soil, as well as flies and observations of human feces. This also included studies that assessed the impact of fecal contamination of water supplies based on distance from sanitation facilities. We identified 29 studies that met the reviews eligibility criteria. RESULTS AND CONCLUSION Overall, the studies found little to no effect from sanitation interventions on these transmission pathways. There was no evidence of effects on water quality (source or household), hand or sentinel toy contamination, food contamination, or contamination of surfaces or soil. There is some evidence that sanitation was associated with reductions in flies and a small effect on observations of feces (Risk Difference -0.03, 95%CI -0.06 to 0.01). Studies show an inverse relationship between the distance of a water supply from a latrine and level of fecal contamination of such water supply. Future evaluations of sanitation interventions should include assessments of effects along transmission pathways in order to better understand the circumstances under which interventions may be effective at preventing disease.

Estimating the Effect of School Water, Sanitation, and Hygiene Improvements on Pupil Health Outcomes

Background: We conducted a cluster-randomized water, sanitation, and hygiene trial in 185 schools in Nyanza province, Kenya. The trial, however, had imperfect school-level adherence at many schools. The primary goal of this study was to estimate the causal effects of school-level adherence to interventions on pupil diarrhea and soil-transmitted helminth infection. Methods: Schools were divided into water availability groups, which were then randomized separately into either water, sanitation, and hygiene intervention arms or a control arm. School-level adherence to the intervention was defined by the number of intervention components—water, latrines, soap—that had been adequately implemented. The outcomes of interest were pupil diarrhea and soil-transmitted helminth infection. We used a weighted generalized structural nested model to calculate prevalence ratio. Results: In the water-scarce group, there was evidence of a reduced prevalence of diarrhea among pupils attending schools that adhered to two or to three intervention components (prevalence ratio = 0.28, 95% confidence interval: 0.10, 0.75), compared with what the prevalence would have been had the same schools instead adhered to zero components or one. In the water-available group, there was no evidence of reduced diarrhea with better adherence. For the soil-transmitted helminth infection and intensity outcomes, we often observed point estimates in the preventive direction with increasing intervention adherence, but primarily among girls, and the confidence intervals were often very wide. Conclusions: Our instrumental variable point estimates sometimes suggested protective effects with increased water, sanitation, and hygiene intervention adherence, although many of the estimates were imprecise.

Sanitation and water supply coverage thresholds associated with active trachoma: Modeling cross-sectional data from 13 countries

Background Facial cleanliness and sanitation are postulated to reduce trachoma transmission, but there are no previous data on community-level herd protection thresholds. We characterize associations between active trachoma, access to improved sanitation facilities, and access to improved water sources for the purpose of face washing, with the aim of estimating community-level or herd protection thresholds. Methods and findings We used cluster-sampled Global Trachoma Mapping Project data on 884,850 children aged 1–9 years from 354,990 households in 13 countries. We employed multivariable mixed-effects modified Poisson regression models to assess the relationships between water and sanitation coverage and trachomatous inflammation—follicular (TF). We observed lower TF prevalence among those with household-level access to improved sanitation (prevalence ratio, PR = 0.87; 95%CI: 0.83–0.91), and household-level access to an improved washing water source in the residence/yard (PR = 0.81; 95%CI: 0.75–0.88). Controlling for household-level water and latrine access, we found evidence of community-level protection against TF for children living in communities with high sanitation coverage (PR80–90% = 0.87; 95%CI: 0.73–1.02; PR90–100% = 0.76; 95%CI: 0.67–0.85). Community sanitation coverage levels greater than 80% were associated with herd protection against TF (PR = 0.77; 95%CI: 0.62–0.97)—that is, lower TF in individuals whose households lacked individual sanitation but who lived in communities with high sanitation coverage. For community-level water coverage, there was no apparent threshold, although we observed lower TF among several of the higher deciles of community-level water coverage. Conclusions Our study provides insights into the community water and sanitation coverage levels that might be required to best control trachoma. Our results suggest access to adequate water and sanitation can be important components in working towards the 2020 target of eliminating trachoma as a public health problem.