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"Larsen, David A"
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An individual-level meta-analysis assessing the impact of community-level sanitation access on child stunting, anemia, and diarrhea: Evidence from DHS and MICS surveys
2017
A lack of access to sanitation is an important risk factor child health, facilitating fecal-oral transmission of pathogens including soil-transmitted helminthes and various causes of diarrheal disease. We conducted a meta-analysis of cross-sectional surveys to determine the impact that community-level sanitation access has on child health for children with and without household sanitation access.
Using 301 two-stage demographic health surveys and multiple indicator cluster surveys conducted between 1990 and 2015 we calculated the sanitation access in the community as the proportion of households in the sampled cluster that had household access to any type of sanitation facility. We then conducted exact matching of children based on various predictors of living in a community with high access to sanitation. Using logistic regression with the matched group as a random intercept we examined the association between the child health outcomes of stunted growth, any anemia, moderate or severe anemia, and diarrhea in the previous two weeks and the exposure of living in a community with varying degrees of community-level sanitation access. For children with household-level sanitation access, living in a community with 100% sanitation access was associated with lowered odds of stunting (adjusted odds ratio [AOR] = 0.97, 95%; confidence interval (CI) = 0.94-1.00; n = 14,153 matched groups, 1,175,167 children), any anemia (AOR = 0.73; 95% CI = 0.67-0.78; n = 5,319 matched groups, 299,033 children), moderate or severe anemia (AOR = 0.72, 95% CI = 0.68-0.77; n = 5,319 matched groups, 299,033 children) and diarrhea (AOR = 0.94; 95% CI = 0.91-0.97); n = 16,379 matched groups, 1,603,731 children) compared to living in a community with < 30% sanitation access. For children without household-level sanitation access, living in communities with 0% sanitation access was associated with higher odds of stunting (AOR = 1.04, 95% CI = 1.02-1.06; n = 14,153 matched groups, 1,175,167 children), any anemia (AOR = 1.05, 95% CI = 1.00-1.09; n = 5,319 matched groups, 299,033 children), moderate or severe anemia (AOR = 1.04, 95% CI = 1.00-1.09; n = 5,319 matched groups, 299,033 children) but not diarrhea (AOR = 1.00, 95% CI = 0.98-1.02; n = 16,379 matched groups, 1,603,731 children) compared to children without household-level sanitation access living in communities with 1-30% sanitation access.
Community-level sanitation access is associated with improved child health outcomes independent of household-level sanitation access. The proportion of children living in communities with 100% sanitation access throughout the world is appallingly low. Ensuring sanitation access to all by 2030 will greatly improve child health.
Journal Article
Comparison of self-reported survey and wastewater-based epidemiology measures of cocaine use on a college campus
2026
Wastewater-based epidemiology (WBE) has the potential to produce reliable, efficient, and non-invasive measures of current psychoactive drug use. The aim of this study was to assess the feasibility and validity of using WBE to estimate current cocaine use among university students at a residential campus.
We analyzed wastewater samples from four locations at a residential university campus during spring semester of 2021, testing for cocaine metabolites in addition to control comparison substances (acetaminophen and caffeine). We simultaneously administered a confidential self-report survey of recent substance use behaviors to a randomized sample of undergraduate students at this university.
Self-reported survey estimates of cocaine use and point estimates of cocaine use derived from wastewater-based epidemiology are similar, but the survey is imprecise with a wide CI, and agreement is sensitive to key WBE assumptions; thus, results are consistent but not conclusive. The self-report survey results indicated 0.13% of respondents were regular cocaine users, which is equivalent to the estimate of 0.12% of students using cocaine as measured through WBE. This prevalence is also in line with the 0.14% National American College Health Association (NACHA) survey during the same semester.
WBE shows promise as a complementary approach for estimating current cocaine use among students on a residential campus; with current data the WBE point estimate is similar to the survey point estimate, but uncertainty in both measures (especially the survey) requires further research.
Journal Article
Effect of Plasmodium falciparum sulfadoxine-pyrimethamine resistance on the effectiveness of intermittent preventive therapy for malaria in pregnancy in Africa: a systematic review and meta-analysis
by
Larsen, David A
,
Hopkins Sibley, Carol
,
Roper, Cally
in
Africa - epidemiology
,
Antimalarial agents
,
Antimalarials - therapeutic use
2019
Resistance of Plasmodium falciparum to sulfadoxine-pyrimethamine threatens the antimalarial effectiveness of intermittent preventive treatment during pregnancy (IPTp) in sub-Saharan Africa. We aimed to assess the associations between markers of sulfadoxine-pyrimethamine resistance in P falciparum and the effectiveness of sulfadoxine-pyrimethamine IPTp for malaria-associated outcomes.
For this systematic review and meta-analysis, we searched databases (from Jan 1, 1990 to March 1, 2018) for clinical studies (aggregated data) or surveys (individual participant data) that reported data on low birthweight (primary outcome) and malaria by sulfadoxine-pyrimethamine IPTp dose, and for studies that reported on molecular markers of sulfadoxine-pyrimethamine resistance. Studies that involved only HIV-infected women or combined interventions were excluded. We did a random-effects meta-analysis (clinical studies) or multivariate log-binomial regression (surveys) to obtain summarised dose-response data (relative risk reduction [RRR]) and multivariate meta-regression to explore the modifying effects of sulfadoxine-pyrimethamine resistance (as indicated by Ala437Gly, Lys540Glu, and Ala581Gly substitutions in the dhps gene). This study is registered with PROSPERO, number 42016035540.
Of 1097 records screened, 57 studies were included in the aggregated-data meta-analysis (including 59 457 births). The RRR for low birthweight declined with increasing prevalence of dhps Lys540Glu (ptrend=0·0060) but not Ala437Gly (ptrend=0·35). The RRR was 7% (95% CI 0 to 13) in areas of high resistance to sulfadoxine-pyrimethamine (Lys540Glu ≥90% in east and southern Africa; n=11), 21% (14 to 29) in moderate-resistance areas (Ala437Gly ≥90% [central and west Africa], or Lys540Glu ≥30% to <90% [east and southern Africa]; n=16), and 27% (21 to 33) in low-resistance areas (Ala437Gly <90% [central and west Africa], or Lys540Glu <30% [east and southern Africa]; n=30; ptrend=0·0054 [univariate], I2=69·5%). The overall RRR in all resistance strata was 21% (17 to 25). In the analysis of individual participant data from 13 surveys (42 394 births), sulfadoxine-pyrimethamine IPTp was associated with reduced prevalence of low birthweight in areas with a Lys540Glu prevalence of more than 90% and Ala581Gly prevalence of less than 10% (RRR 10% [7 to 12]), but not in those with an Ala581Gly prevalence of 10% or higher (pooled Ala581Gly prevalence 37% [range 29 to 46]; RRR 0·5% [–16 to 14]; 2326 births).
The effectiveness of sulfadoxine-pyrimethamine IPTp is reduced in areas with high resistance to sulfadoxine-pyrimethamine among P falciparum parasites, but remains associated with reductions in low birthweight even in areas where dhps Lys540Glu prevalence exceeds 90% but where the sextuple-mutant parasite (harbouring the additional dhps Ala581Gly mutation) is uncommon. Therapeutic alternatives to sulfadoxine-pyrimethamine IPTp are needed in areas where the prevalence of the sextuple-mutant parasite exceeds 37%.
US Centers for Disease Control and Prevention, the Malaria in Pregnancy Consortium (funded through a grant from the Bill & Melinda Gates Foundation to the Liverpool School of Tropical Medicine), Worldwide Antimalarial Resistance Network, European and Developing Countries Clinical Trials Partnership.
Journal Article
Malaria prevention in pregnancy, birthweight, and neonatal mortality: a meta-analysis of 32 national cross-sectional datasets in Africa
2012
Low birthweight is a significant risk factor for neonatal and infant death. A prominent cause of low birthweight is infection with Plasmodium falciparum during pregnancy. Antimalarial intermittent preventive therapy in pregnancy (IPTp) and insecticide-treated mosquito nets (ITNs) significantly reduce the risk of low birthweight in regions of stable malaria transmission. We aimed to assess the effectiveness of malaria prevention in pregnancy (IPTp or ITNs) at preventing low birthweight and neonatal mortality under routine programme conditions in malaria endemic countries of Africa.
We used a retrospective birth cohort from national cross-sectional datasets in 25 African countries from 2000–10. We used all available datasets from multiple indicator cluster surveys, demographic and health surveys, malaria indicator surveys, and AIDS indicator surveys that were publically available as of 2011. We tried to limit confounding bias through exact matching on potential confounding factors associated with both exposure to malaria prevention (ITNs or IPTp with sulfadoxine–pyrimethamine) in pregnancy and birth outcomes, including local malaria transmission, neonatal tetanus vaccination, maternal age and education, and household wealth. We used a logistic regression model to test for associations between malaria prevention in pregnancy and low birthweight, and a Poisson model for the outcome of neonatal mortality. Both models incorporated the matched strata as a random effect, while accounting for additional potential confounding factors with fixed effect covariates.
We analysed 32 national cross-sectional datasets. Exposure of women in their first or second pregnancy to full malaria prevention with IPTp or ITNs was significantly associated with decreased risk of neonatal mortality (protective efficacy [PE] 18%, 95% CI 4–30; incidence rate ratio [IRR] 0·820, 95% CI 0·698–0·962), compared with newborn babies of mothers with no protection, after exact matching and controlling for potential confounding factors. Compared with women with no protection, exposure of pregnant women during their first two pregnancies to full malaria prevention in pregnancy through IPTp or ITNs was significantly associated with reduced odds of low birthweight (PE 21%, 14–27; IRR 0·792, 0·732–0·857), as measured by a combination of weight and birth size perceived by the mother, after exact matching and controlling for potential confounding factors.
Malaria prevention in pregnancy is associated with substantial reductions in neonatal mortality and low birthweight under routine malaria control programme conditions. Malaria control programmes should strive to achieve full protection in pregnant women by both IPTp and ITNs to maximise their benefits. Despite an attempt to mitigate bias and potential confounding by matching women on factors thought to be associated with access to malaria prevention in pregnancy and birth outcomes, some level of confounding bias possibly remains.
Malaria Control and Evaluation Partnership in Africa (MACEPA), Bill & Melinda Gates Foundation.
Journal Article
Routine deworming during antenatal care decreases risk of neonatal mortality and low birthweight: A retrospective cohort of survey data
by
Kmush, Brittany L.
,
Endy, Timothy
,
Larsen, David A.
in
Adolescent
,
Adult
,
Anthelmintics - therapeutic use
2021
Soil transmitted helminths (STH) are a common infection among pregnant women in areas with poor access to sanitation. Deworming medications are cheap and safe; however, the health benefit of deworming during pregnancy is not clear.
We created a retrospective cohort of more than 800,000 births from 95 Demographic and Health Survey datasets to estimate the impact of deworming medicine during routine antenatal care (ANC) on neonatal mortality and low birthweight. We first matched births on the probability of receiving deworming during ANC. We then modeled the birth outcomes with the matched group as a random intercept to estimate the effect of deworming during antenatal care after accounting for various risk factors. We also tested for effect modification of soil transmitted helminth prevalence on the impact of deworming during ANC. Receipt of deworming medication during ANC was associated with a 14% reduction in the risk of neonatal mortality (95% confidence interval = 10-17%, n = 797,772 births), with no difference between high and low transmission countries. In low transmission countries, we found an 11% reduction in the odds of low birth weight (95% confidence interval = 8-13%) for women receiving deworming medicine, and in high transmission countries, we found a 2% reduction in the odds of low birthweight (95% confidence interval = 0-5%).
These results suggest a substantial health benefit for deworming during ANC that may be even greater in countries with low STH transmission.
Journal Article
Tracking COVID-19 with wastewater
2020
Wastewater testing captures the rise and fall of novel coronavirus cases in a mid-sized metropolitan region.
Journal Article
How local health departments use wastewater surveillance data for public health planning and intervention in New York State
2025
Wastewater surveillance presents a novel data stream for local health departments to understand infectious disease risk in their communities. We conducted a survey of local health departments in New York State regarding their knowledge, attitudes, and practices toward wastewater surveillance of SARS-CoV-2. We further conducted in-depth interviews with a number of local health departments to identify specific use cases of wastewater surveillance data. Almost all survey respondents used wastewater surveillance data and reported advantages to wastewater surveillance data, with the most common use being the tracking of disease trends, followed by monitoring variants, detecting diseases early, and assessing public health interventions. Some counties were sharing wastewater surveillance data with hospitals, which use the data for planning purposes. Public health communication was the most commonly reported action taken from wastewater surveillance data. These findings highlight that local health departments generally have favorable attitudes toward wastewater surveillance. However, there is a need for continued training and support for local health departments to apply these data in their practice.
Journal Article
Spatio-temporal patterns of gun violence in Syracuse, New York 2009-2015
by
Lane, Sandra
,
Haygood-El, Arnett
,
Rubinstein, Robert A.
in
Addictions
,
Addictive behaviors
,
African Americans
2017
Gun violence in the United States of America is a large public health problem that disproportionately affects urban areas. The epidemiology of gun violence reflects various aspects of an infectious disease including spatial and temporal clustering. We examined the spatial and temporal trends of gun violence in Syracuse, New York, a city of 145,000. We used a spatial scan statistic to reveal spatio-temporal clusters of gunshots investigated and corroborated by Syracuse City Police Department for the years 2009-2015. We also examined predictors of areas with increased gun violence using a multi-level zero-inflated Poisson regression with data from the 2010 census. Two space-time clusters of gun violence were revealed in the city. Higher rates of segregation, poverty and the summer months were all associated with increased risk of gun violence. Previous gunshots in the area were associated with a 26.8% increase in the risk of gun violence. Gun violence in Syracuse, NY is both spatially and temporally stable, with some neighborhoods of the city greatly afflicted.
Journal Article
Widespread mosquito net fishing in the Barotse floodplain: Evidence from qualitative interviews
by
Welsh, Rick
,
Larsen, David A.
,
Reid, Robert
in
Aquatic insects
,
Biology and Life Sciences
,
Chemical properties
2018
The insecticide-treated mosquito net (ITN) is a crucial component of malaria control programs, and has prevented many malaria cases and deaths due to scale up. ITNs also serve effectively as fishing nets and various sources have reported use of ITNs for fishing. This article examines how widespread the practice of mosquito net fishing with ITNs is.
We conducted in-depth interviews with fishery personnel and traditional leadership from the Barotse Royal Establishment in Western Province, Zambia, to better understand the presence or absence of the use of ITNs as fishing nets. We then coded the interviews for themes through content analysis. Additionally we conducted a desk review of survey data to show trends in malaria indicators, nutritional status of the population and fish consumption.
All those interviewed reported that ITNs are regularly used for fishing in Western Zambia and the misuse is widespread. Concurrently those interviewed reported declines in fish catches both in terms of quantity and quality leading to threatened food security in the area. In addition to unsustainable fishing practices those interviewed referenced drought and population pressure as reasons for fishery decline. Malaria indicators do not show a trend in declining malaria transmission, fish consumption has dropped dramatically and nutritional status has not improved over time.
Despite the misuse of the ITNs for fishing all those interviewed maintained that ITN distribution should continue. Donors, control programs and scientists should realize that misuse of ITNs as fishing nets is a current problem for malaria control and potentially for food security that needs to be addressed.
Journal Article
Coverage of intermittent preventive treatment and insecticide-treated nets for the control of malaria during pregnancy in sub-Saharan Africa: a synthesis and meta-analysis of national survey data, 2009–11
by
Larsen, David A
,
Hill, Jenny
,
van Eijk, Anna Maria
in
Adult
,
Africa South of the Sahara
,
Antimalarials - administration & dosage
2013
Pregnant women in malaria-endemic countries in sub-Saharan Africa are especially vulnerable to malaria. Recommended prevention strategies include intermittent preventive treatment with two doses of sulfadoxine–pyrimethamine and the use of insecticide-treated nets. However, progress with implementation has been slow and the Roll Back Malaria Partnership target of 80% coverage of both interventions by 2010 has not been met. We aimed to review the coverage of intermittent preventive treatment, insecticide-treated nets, and antenatal care for pregnant women in sub-Saharan Africa and to explore associations between coverage and individual and country-level factors, including the role of funding for malaria prevention.
We used data from nationally representative household surveys from 2009–11 to estimate coverage of intermittent preventive treatment, use of insecticide-treated nets, and attendance at antenatal clinics by pregnant women in sub-Saharan Africa. Using demographic data for births and published data for malaria exposure, we also estimated the number of malaria-exposed births (livebirths and stillbirths combined) for 2010 by country. We used meta-regression analysis to investigate the factors associated with coverage of intermittent preventive treatment and use of insecticide-treated nets.
Of the 21·4 million estimated malaria-exposed births across 27 countries in 2010, an estimated 4·6 million (21·5%, 95% CI 19·3–23·7) were born to mothers who received intermittent preventive treatment. Insecticide-treated nets were used during pregnancy for 10·5 million of 26·9 million births across 37 countries (38·8%, 34·6–43·0). Antenatal care was attended at least once by 16·3 of 20·8 million women in 2010 (78·3%, 75·2–81·4; n=26 countries) and at least twice by 14·7 of 19·6 million women (75·1%, 72·9–77·3; n=22 countries). For the countries with previous estimates for 2007, coverage of intermittent preventive treatment increased from 13·1% (11·9–14·3) to 21·2% (18·9–23·5; n=14 countries) and use of insecticide-treated nets increased from 17·9% (15·1–20·7) to 41·6% (37·2–46·0; n=24 countries) in 2010. A fall in coverage by more than 10% was seen in two of 24 countries for intermittent preventive treatment and in three of 30 countries for insecticide-treated nets. High disbursement of funds for malaria control and a long time interval since adoption of the relevant policy were associated with the highest coverage of intermittent preventive treatment. High disbursement of funds for malaria control and high total fertility rate were associated with the greatest use of insecticide-treated nets, whereas a high per-head gross domestic product (GDP) was associated with less use of nets than was a lower GDP. Coverage of intermittent preventive treatment showed greater inequity overall than use of insecticide-treated nets, with richer, educated, and urban women more likely to receive preventive treatment than their poorer, uneducated, rural counterparts.
Although coverage of intermittent preventive treatment and use of insecticide-treated nets by pregnant women has increased in most countries, coverage remains far below international targets, despite fairly high rates of attendance at antenatal clinics. The effect of the implementation of WHO's 2012 policy update for intermittent preventive treatment, which aims to simplify the message and align preventive treatment with the focused antenatal care schedule, should be assessed to find out whether it leads to improvements in coverage.
Bill & Melinda Gates Foundation.
Journal Article