Background: Previous epidemiologic studies suggest associations between preterm birth and ambient air pollution. Objective: We investigated associations between 11 ambient air pollutants, estimated by combining Community Multiscale Air Quality model (CMAQ) simulations with measurements from stationary monitors, and risk of preterm birth (< 37 weeks of gestation) in the U.S. state of Georgia. Methods: Birth records for singleton births ≥ 27 weeks of gestation with complete covariate information and estimated dates of conception between 1 January 2002 and 28 February 2006 were obtained from the Office of Health Indicators for Planning, Georgia Department of Public Health (n = 511,658 births). Daily pollutant concentrations at 12-km resolution were estimated for 11 ambient air pollutants. We used logistic regression with county-level fixed effects to estimate associations between preterm birth and average pollutant concentrations during the first and second trimester. Discrete-time survival models were used to estimate third-trimester and total pregnancy associations. Effect modification was investigated by maternal education, race, census tract poverty level, and county-level urbanicity. Results: Trimester-specific and total pregnancy associations (p < 0.05) were observed for several pollutants. All the traffic-related pollutants (carbon monoxide, nitrogen dioxide, PM2.5 elemental carbon) were associated with preterm birth [e.g., odds ratios for interquartile range increases in carbon monoxide during the first, second, and third trimesters and total pregnancy were 1.005 (95% CI: 1.001, 1.009), 1.007 (95% CI: 1.002, 1.011), 1.010 (95% CI: 1.006, 1.014), and 1.011 (95% CI: 1.006, 1.017)]. Associations tended to be higher for mothers with low educational attainment and African American mothers. Conclusion: Several ambient air pollutants were associated with preterm birth; associations were observed in all exposure windows.
Background:Preventive chemotherapy represents a powerful but short-term control strategy for soil-transmitted helminthiasis. Since humans are often re-infected rapidly, long-term solutions require improvements in water, sanitation, and hygiene (WASH). The purpose of this study was to quantitatively summarize the relationship between WASH access or practices and soil-transmitted helminth (STH) infection.Methods and Findings:We conducted a systematic review and meta-analysis to examine the associations of improved WASH on infection with STH (Ascaris lumbricoides, Trichuris trichiura, hookworm [Ancylostoma duodenale and Necator americanus], and Strongyloides stercoralis). PubMed, Embase, Web of Science, and LILACS were searched from inception to October 28, 2013 with no language restrictions. Studies were eligible for inclusion if they provided an estimate for the effect of WASH access or practices on STH infection. We assessed the quality of published studies with the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach. A total of 94 studies met our eligibility criteria; five were randomized controlled trials, whilst most others were cross-sectional studies. We used random-effects meta-analyses and analyzed only adjusted estimates to help account for heterogeneity and potential confounding respectively.Use of treated water was associated with lower odds of STH infection (odds ratio [OR] 0.46, 95% CI 0.36-0.60). Piped water access was associated with lower odds of A. lumbricoides (OR 0.40, 95% CI 0.39-0.41) and T. trichiura infection (OR 0.57, 95% CI 0.45-0.72), but not any STH infection (OR 0.93, 95% CI 0.28-3.11). Access to sanitation was associated with decreased likelihood of infection with any STH (OR 0.66, 95% CI 0.57-0.76), T. trichiura (OR 0.61, 95% CI 0.50-0.74), and A. lumbricoides (OR 0.62, 95% CI 0.44-0.88), but not with hookworm infection (OR 0.80, 95% CI 0.61-1.06). Wearing shoes was associated with reduced odds of hookworm infection (OR 0.29, 95% CI 0.18-0.47) and infection with any STH (OR 0.30, 95% CI 0.11-0.83). Handwashing, both before eating (OR 0.38, 95% CI 0.26-0.55) and after defecating (OR 0.45, 95% CI 0.35-0.58), was associated with lower odds of A. lumbricoides infection. Soap use or availability was significantly associated with lower infection with any STH (OR 0.53, 95% CI 0.29-0.98), as was handwashing after defecation (OR 0.47, 95% CI 0.24-0.90).Observational evidence constituted the majority of included literature, which limits any attempt to make causal inferences. Due to underlying heterogeneity across observational studies, the meta-analysis results reflect an average of many potentially distinct effects, not an average of one specific exposure-outcome relationship.Conclusions:WASH access and practices are generally associated with reduced odds of STH infection. Pooled estimates from all meta-analyses, except for two, indicated at least a 33% reduction in odds of infection associated with individual WASH practices or access. Although most WASH interventions for STH have focused on sanitation, access to water and hygiene also appear to significantly reduce odds of infection. Overall quality of evidence was low due to the preponderance of observational studies, though recent randomized controlled trials have further underscored the benefit of handwashing interventions. Limited use of the Joint Monitoring Program's standardized water and sanitation definitions in the literature restricted efforts to generalize across studies. While further research is warranted to determine the magnitude of benefit from WASH interventions for STH control, these results call for multi-sectoral, integrated intervention packages that are tailored to social-ecological contexts.Please see later in the article for the Editors' Summary.
Using an international dataset compiled from 121 sites in 87 marine protected areas (MPAs) globally (Edgar et al., 2014), I assessed how various configurations of design and management conditions affected MPA ecological performance, measured in terms of fish species richness and biomass. The set-theoretic approach used Boolean algebra to identify pathways that combined up to five 'NEOLI' (No-take, Enforced, Old, Large, Isolated) conditions and that were sufficient for achieving positive, and negative, ecological outcomes. Ecological isolation was overwhelming the most important condition affecting ecological outcomes but Old and Large were also conditions important for achieving high levels of biomass among large fishes (jacks, groupers, sharks). Solution coverage was uniformly low (<0.35) for all models of positive ecological performance suggesting the presence of numerous other conditions and pathways to ecological success that did not involve the NEOLI conditions. Solution coverage was higher (>0.50) for negative results (i.e., the absence of high biomass) among the large commercially-exploited fishes, implying asymmetries in how MPAs may rebuild populations on the one hand and, on the other, protect against further decline. The results revealed complex interactions involving MPA design, implementation, and management conditions that affect MPA ecological performance. In general terms, the presence of no-take regulations and effective enforcement were insufficient to ensure MPA effectiveness on their own. Given the central role of ecological isolation in securing ecological benefits from MPAs, site selection in the design phase appears critical for success.
Background
Trachoma is the world's leading cause of infectious blindness. The World Health Organization (WHO) has endorsed the SAFE strategy in order to eliminate blindness due to trachoma by 2020 through “surgery,” “antibiotics,” “facial cleanliness,” and “environmental improvement.” While the S and A components have been widely implemented, evidence and specific targets are lacking for the F and E components, of which water, sanitation, and hygiene (WASH) are critical elements. Data on the impact of WASH on trachoma are needed to support policy and program recommendations. Our objective was to systematically review the literature and conduct meta-analyses where possible to report the effects of WASH conditions on trachoma and identify research gaps.
Methods and Findings
We systematically searched PubMed, Embase, ISI Web of Knowledge, MedCarib, Lilacs, REPIDISCA, DESASTRES, and African Index Medicus databases through October 27, 2013 with no restrictions on language or year of publication. Studies were eligible for inclusion if they reported a measure of the effect of WASH on trachoma, either active disease indicated by observed signs of trachomatous inflammation or Chlamydia trachomatis infection diagnosed using PCR. We identified 86 studies that reported a measure of the effect of WASH on trachoma. To evaluate study quality, we developed a set of criteria derived from the GRADE methodology. Publication bias was assessed using funnel plots. If three or more studies reported measures of effect for a comparable WASH exposure and trachoma outcome, we conducted a random-effects meta-analysis. We conducted 15 meta-analyses for specific exposure-outcome pairs. Access to sanitation was associated with lower trachoma as measured by the presence of trachomatous inflammation-follicular or trachomatous inflammation-intense (TF/TI) (odds ratio [OR] 0.85, 95% CI 0.75–0.95) and C. trachomatis infection (OR 0.67, 95% CI 0.55–0.78). Having a clean face was significantly associated with reduced odds of TF/TI (OR 0.42, 95% CI 0.32–0.52), as were facial cleanliness indicators lack of ocular discharge (OR 0.42, 95% CI 0.23–0.61) and lack of nasal discharge (OR 0.62, 95% CI 0.52–0.72). Facial cleanliness indicators were also associated with reduced odds of C. trachomatis infection: lack of ocular discharge (OR 0.40, 95% CI 0.31–0.49) and lack of nasal discharge (OR 0.56, 95% CI 0.37–0.76). Other hygiene factors found to be significantly associated with reduced TF/TI included face washing at least once daily (OR 0.76, 95% CI 0.57–0.96), face washing at least twice daily (OR 0.85, 95% CI 0.80–0.90), soap use (OR 0.76, 95% CI 0.59–0.93), towel use (OR 0.65, 95% CI 0.53–0.78), and daily bathing practices (OR 0.76, 95% CI 0.53–0.99). Living within 1 km of a water source was not found to be significantly associated with TF/TI or C. trachomatis infection, and the use of sanitation facilities was not found to be significantly associated with TF/TI.
Conclusions
We found strong evidence to support F and E components of the SAFE strategy. Though limitations included moderate to high heterogenity, low study quality, and the lack of standard definitions, these findings support the importance of WASH in trachoma elimination strategies and the need for the development of standardized approaches to measuring WASH in trachoma control programs.
Please see later in the article for the Editors' Summary
by
Thomas R. Gillespie;
Elizabeth V. Lonsdorf;
Elizabeth P. Canfield;
Derek J. Meyer;
Yvonne Nadler;
Jane Raphael;
Anne E. Pusey;
Joel Pond;
John Pauley;
Titus Mlengeya;
Dominic A. Travis
From January 2006 to January 2008, we collected 1,045 fecal samples from 90 individually-recognized, free-ranging, eastern chimpanzees (Pan troglodytes schweinfurthii) inhabiting Gombe National Park, Tanzania to determine how patterns of parasitism are affected by demographic and ecological covariates. Seventeen parasite species were recovered, including eight nematodes (Oesophagostomum sp., Necator sp., Probstmayria gombensis, Strongyloides fulleborni, Ascaris sp., Trichuris sp., Abbreviata caucasica, and an unidentified strongyle), 1 cestode (Bertiella sp.), 1 trematode (Dicrocoeliidae), and 7 protozoa (Entamoeba coli, Entamoeba histolytica/dispar, Iodamoeba bütschlii, Troglodytella abrassarti, Troglocorys cava, Balantidium coli, and an unidentified protozoa). Significant differences were observed in interannual infection prevalence and parasite richness between 2006 and 2007. Intercommunity comparisons demonstrated higher prevalence of parasites for the Mitumba compared with Kasekela chimpanzee community. Prevalence of several parasites was strongly correlated with monthly rainfall patterns for both 2006 and 2007. Subadult chimpanzees had lower prevalence for most parasite species compared with adults in both years and also yielded a lower average parasite species richness. No significant differences were observed between males and females in prevalence in 2006. However, in 2007 the prevalence of S. fulleborni and I. bütschlii were higher in males than in females. Parasite prevalence and richness were substantially higher in this multiyear study compared with previous short-term studies of the gastrointestinal parasites of Gombe chimpanzees. This coupled with the significant interannual and interseasonal variation, demonstrated in this study, emphasizes the importance of multiyear monitoring with adequate sample size to effectively determine patterns of parasitism in wild primate populations.
Carotenoids, vitamin A and tocopherols serve important roles in many key body functions. However, availability of these compounds may be decreased in patients with short bowel syndrome (SBS) due to decreased oral intake of fruits and vegetables and/or decreased intestinal absorption. Little information is available on serum concentrations of carotenoids, vitamin A and tocopherols during chronic parenteral nutrition (PN) or during PN weaning. The aim of this study was to prospectively examine serum concentrations of a wide variety of carotenoids, vitamin A and tocopherols in SBS patients undergoing an intensive 12-week intestinal rehabilitation program. Twenty-one PN-dependent adult SBS patients were enrolled in a 12-week intestinal rehabilitation program, which included individualized dietary modification, multivitamin supplementation, and randomization to receive either s.c. placebo (n=9) or human growth hormone (GH, 0.1 mg/kg/day). PN weaning was initiated after week 4 and advanced as tolerated. Serum concentrations of carotenoids, vitamin A and tocopherols were determined at baseline and at weeks 4 and 12. Results showed that a significant % of subjects exhibited low serum concentrations for carotenoids and α-tocopherol at study entry, while a few subjects had low concentrations of retinol (5%). Serum α-tocopherol concentration was negatively associated with PN lipid dose (r = - 0.34, p < 0.008). We conclude that SBS patients are depleted in diet-derived carotenoids despite oral and intravenous multivitamin supplementation and dietary adjustment during intestinal rehabilitation and PN weaning. Reduction of PN lipid infusion may improve serum α-tocopherol concentrations.
An estimated 200,000 children born in Thailand each year are at risk of prenatal exposure to pesticides and associated neurodevelopmental outcomes because of their mothers' agricultural occupations. Children born to non-agricultural workers may also be at risk of exposure from other pathways of maternal pesticide exposure, including exposure through home use, diet, and other environmental media. Pesticide exposure in Thailand has been linked to unsafe practices and beliefs about pesticides. However, limited information exists on pesticide knowledge, attitudes, and practices among pregnant women in Thailand or elsewhere. Obtaining this information is essential to understand the factors associated with prenatal pesticide exposure, identify populations potentially at risk, and ultimately protect pregnant women and their children. We administered surveys to 76 pregnant women in northern Thailand and used multivariable logistic regression to evaluate associations among pesticide- related knowledge, pregnancy trimester, and pesticide use behavior. In this pilot study, lower knowledge score and earliest trimester of pregnancy were marginally (p < 0.1) associated with unsafe practices in the home, but not at work. Women who worked in agriculture or applied pesticides before becoming pregnant, or who had a previous child were significantly (p < 0.05) more likely to engage in unsafe behaviors in the home during their current pregnancy. We preliminarily conclude that increasing pesticide-related knowledge among pregnant women may help promote safe practices and reduce prenatal exposure. Knowledge-based interventions may be most effective when implemented early in pregnancy and targeted to agricultural workers and other sub-populations at risk of pesticide exposure.
by
William Lewis;
James J Kohler;
Seyed H. Hosseini;
Chad P. Haase;
William C. Copeland;
Rachelle J. Bienstock;
Tomika Ludaway;
Jamie McNaught;
Rodney Russ;
Tami Stuart;
Robert Santoianni
Design
Nucleoside reverse transcriptase inhibitors (NRTIs) exhibit mitochondrial toxicity. The mitochondrial deoxynucleotide carrier (DNC) transports nucleotide precursors (or phosphorylated NRTIs) into mitochondria for mitochondrial (mt)DNA replication or inhibition of mtDNA replication by NRTIs. Transgenic mice (TG) expressing human DNC targeted to murine myocardium served to define mitochondrial events from NRTIs in vivo and findings were corroborated by biochemical events in vitro.
Methods
Zidovudine (3′-azido-2′,3′-deoxythymidine; ZDV), stavudine (2′, 3′-didehy-dro-2′, 3′-deoxythymidine; d4T), or lamivudine ((−)-2′-deoxy-3′-thiacytidine; 3TC) were administered individually to TGs and wild-type (WT) littermates (35 days) at human doses with drug-free vehicle as control. Left ventricle (LV) mass was defined echocardiographically, mitochondrial ultrastructural defects were identified by electron microscopy, the abundance of cardiac mtDNA was quantified by real time polymerase chain reaction, and mtDNA-encoded polypeptides were quantified.
Results
Untreated TGs exhibited normal LV mass with minor mitochondrial damage. NRTI monotherapy (either d4T or ZDV) increased LV mass in TGs and caused significant mitochondrial destruction. Cardiac mtDNA was depleted in ZDV and d4T-treated TG hearts and mtDNA-encoded polypeptides decreased. Changes were absent in 3TC-treated cohorts. In supportive structural observations from molecular modeling, ZDV demonstrated close contacts with K947 and Y951 in the DNA pol γ active site that were absent in the HIV reverse transcriptase active site.
Conclusions
NRTIs deplete mtDNA and polypeptides, cause mitochondrial structural and functional defects in vivo, follow inhibition kinetics with DNA pol γ in vitro, and are corroborated by molecular models. Disrupted pools of nucleotide precursors and inhibition of DNA pol γ by specific NRTIs are mechanistically important in mitochondrial toxicity.
We employed a cluster-randomized trial design to measure the impact of a school-based water, sanitation and hygiene (WASH) improvement on pupil enrolment and on gender parity in enrolment, in primary schools in Nyanza Province, Kenya (2007-2009). Among schools with poor water access during the dry season, those that received a water supply, hygiene promotion and water treatment (HP&WT) and sanitation improvement demonstrated increased enrolment (β = 0.091 [0.009, 0.173] p = 0.03), which translates to 26 additional pupils per school on average. The proportion of girls enrolled in school also increased by 4% (prevalence ratio (PR) = 1.04 [1.00, 1.07] p = 0.02). Among schools with better baseline water access during the dry season (schools that did not receive a water source), we found no evidence of increased enrolment in schools that received a HP&WT intervention (β = 0.016 [-0.039, 0.072] p = 0.56) or the HP&WT and sanitation intervention (β = 0.027 [-0.028, 0.082] p = 0.34), and there was no evidence of improved gender parity (PR = 0.99 [0.96, 1.02] p = 0.59, PR = 1.00 [0.97, 1.02] p = 0.75, respectively). Our findings suggest that increased school enrolment and improved gender parity may be influenced by a comprehensive WASH programme that includes an improved water source; schools with poor water access during the dry season may benefit most from these interventions.
by
Annette Pruss-Ustun;
Jennyfer Wolf;
Jamie Bartram;
Thomas Clasen;
Oliver Cumming;
Bruce Gordon;
Matthew Freeman;
Paul R. Hunter;
Kate Medlicott;
Richard Johnston
Background: To develop updated estimates in response to new exposure and exposure-response data of the burden of diarrhoea, respiratory infections, malnutrition, schistosomiasis, malaria, soil-transmitted helminth infections and trachoma from exposure to inadequate drinking-water, sanitation and hygiene behaviours (WASH) with a focus on low- and middle-income countries.
Methods: For each of the analysed diseases, exposure levels with both sufficient global exposure data for 2016 and a matching exposure-response relationship were combined into population-attributable fractions. Attributable deaths and disability-adjusted life years (DALYs) were estimated for each disease and, for most of the diseases, by country, age and sex group separately for inadequate water, sanitation and hygiene behaviours and for the cluster of risk factors. Uncertainty estimates were computed on the basis of uncertainty surrounding exposure estimates and relative risks.
Findings: An estimated 829,000 WASH-attributable deaths and 49.8 million DALYs occurred from diarrhoeal diseases in 2016, equivalent to 60% of all diarrhoeal deaths. In children under 5 years, 297,000 WASH-attributable diarrhoea deaths occurred, representing 5.3% of all deaths in this age group. If the global disease burden from different diseases and several counterfactual exposure distributions was combined it would amount to 1.6 million deaths, representing 2.8% of all deaths, and 104.6 million DALYs in 2016.
Conclusions: Despite recent declines in attributable mortality, inadequate WASH remains an important determinant of global disease burden, especially among young children. These estimates contribute to global monitoring such as for the Sustainable Development Goal indicator on mortality from inadequate WASH.