Health Surveys Program Research Articles

Socioeconomic, Demographic, and Environmental Factors May Inform Malaria Intervention Prioritization in Urban Nigeria.

Urban population growth in Nigeria may exceed the availability of affordable housing and basic services, resulting in living conditions conducive to vector breeding and heterogeneous malaria transmission. Understanding the link between community-level factors and urban malaria transmission informs targeted interventions. We analyzed Demographic and Health Survey Program cluster-level data, alongside geospatial covariates, to describe variations in malaria prevalence in children under 5 years of age. Univariate and multivariable models explored the relationship between malaria test positivity rates at the cluster level and community-level factors. Generally, malaria test positivity rates in urban areas are low and declining. The factors that best predicted malaria test positivity rates within a multivariable model were post-primary education, wealth quintiles, population density, access to improved housing, child fever treatment-seeking, precipitation, and enhanced vegetation index. Malaria transmission in urban areas will likely be reduced by addressing socioeconomic and environmental factors that promote exposure to disease vectors. Enhanced regional surveillance systems in Nigeria can provide detailed data to further refine our understanding of these factors in relation to malaria transmission.

Association between Dietary Potassium Intake and Nonalcoholic Fatty Liver Disease and Advanced Hepatic Fibrosis in U.S. Adults.

The correlation between potassium and nonalcoholic fatty liver disease (NAFLD) is currently still poorly understood. We conducted this study to explore the correlation between dietary potassium intake and NAFLD, as well as advanced hepatic fibrosis (AHF). The study also sought to identify any potential interactions. The data employed in this study were obtained from the National Health and Nutrition Examination Survey (NHANES) program, encompassing a period from 2007 to 2018. Employing the multiple logistic regression analysis, we evaluated the association of dietary potassium intake with NAFLD and AHF. Subsequently, stratification analysis, based on demographic variables, was constructed so as to assess the stability of the results. In addition, potential interaction effects were assessed by interaction tests. A total of 9443 participants were included in the analysis. The mean age of the participants was 50.4 years, and their daily mean dietary potassium and vitamin C intake was 2556.49 mg and 82.93 mg, respectively. Following comprehensive statistical analyses, the findings indicated a negative correlation between dietary potassium intake and both NAFLD and AHF. Participants in Q4 group with dietary potassium intake exhibited a 31% and 42% reduction in the odds of developing NAFLD and AHF, respectively, in comparison to Q1 group. An interaction effect of dietary vitamin C intake was observed in the association between dietary potassium intake and NAFLD. The results imply that high dietary vitamin C intake augment the inverse relationship between dietary potassium intake and NAFLD. Dietary potassium intake was found to have an inverse association with the odds of both NAFLD and AHF. The association between dietary potassium intake and NAFLD was amplified by the presence of vitamin C in the diet.

The Collision of Global Scripts with Local Constraints: Education as a Risk Factor for Unintended Pregnancy

Extensive sociological research concludes that education informs people’s desires for their lives and plays an instrumental role in facilitating the fulfillment of those desires. In this article, we ask if societal barriers can leave the most educated to desire outcomes that are unattainable and thus paradoxically place them at highest risk of unwanted outcomes. We answer this question by analyzing societal variation in the potential for education to facilitate women achieving their lower fertility desires: Are there fertility contexts wherein educated women’s lower fertility desires are distinctly unattainable? Multilevel models analyzing Demographic and Health Survey Program data on women from 50 low- and middle-income countries emphasize the collision of global scripts with local constraints: In low contraceptive contexts, education is associated with higher risk of unintended pregnancy. The results clarify that the potential for education to facilitate the achievement of desires is fraught with contingencies.

Serum HDL partially mediates the association between exposure to volatile organic compounds and kidney stones: A nationally representative cross-sectional study from NHANES

Environmental exposure to volatile organic compounds (VOCs) is ubiquitous, and this study explored whether exposure to VOCs is associated with the risk of kidney stones. We performed a nationally representative US cross-sectional study using data from five survey cycles (2011–2020) of the National Health and Nutrition Examination Survey (NHANES) program. Exposure to VOCs was determined by urine creatinine-corrected metabolites of VOCs (mVOCs). In total 5505 participants and 15 urine mVOCs were included for analysis, and the prevalence of kidney stones was 9.57 % (527/5505). Multivariable logistic regression showed that urine AMCC (parent VOCs (pVOCs): N, N-Dimethylformamide), 3,4-MHA (pVOCs: xylene), MA (pVOCs: ethylbenzene; styrene), DHBMA (pVOCs: 1,3-butadiene), HMPMA (pVOCs: crotonaldehyde) and 2HPMA (pVOCs: propylene oxide) were significantly associated with an increased risk of kidney stones in US general population. Sub-analysis revealed that there was a more pronounced association in women and the overweight/obesity group (body mass index ≥ 25). Moreover, the weighted quantile sum (WQS) regression model and the Bayesian kernel machine regression (BKMR) model consistently identified a positive association between co-exposure to VOCs and the risk of kidney stones, in which AMCC played the most important role among the 15 mVOCs. Mediation analysis further identified serum high-density lipoprotein cholesterol (HDL) as a mediator of the association between VOC co-exposure and kidney stones. Our study draws attention to the previously unknown positive associations between non-occupational VOC exposure and the risk of kidney stones in the general population. However, further studies are required to clarify the existence of such causation.

Association between mixed urinary metal exposure and liver function: analysis of NHANES data.

Metals have been reported to affect liver functions; however, the association between mixed metal exposure in the urine and liver functions remains unclear. The present study analyzed data from the National Health and Nutrition Examination Survey (NHANES) program collected in 2005-2018. Weighted multiple linear regression and Bayesian kernel machine regression (BKMR) were used to explore the relationship between mixed urinary metal contents and liver function tests (LFTs). A total of 8158 participants were analyzed in this study. Multiple methods suggested that cadmium (Cd) was significantly positively related to LFTs, while cobalt (Co) was negatively related to LFTs. Meanwhile, some other metals showed a significant relationship with some indicators of LFTs. Urine metal is related to LFTs, with Cd and Co content changes being closely related to LFTs. The metal in urine may represent a marker for predicting liver dysfunction. Further studies are needed to verify this hypothesis.

Floods and Diarrhea Risk in Young Children in Low- and Middle-Income Countries

Climate change is associated with more frequent and intense floods. Current research on the association between flood exposure and diarrhea risk is limited mainly to short-term and event-specific analyses. Moreover, how prior drought or water, sanitation, and hygiene (WaSH) practices influence this association remains largely unknown. To examine the association between flood exposure and diarrhea risk among children younger than 5 years and to evaluate the compounding influence of prior drought and effect modification by WaSH. This cross-sectional study included multicluster surveys conducted by the Demographic and Health Surveys Program in 43 low- and middle-income countries during 2009 through 2019. This study included children younger than 5 years in all households from each survey cluster. Collected data were analyzed between September 1 and December 31, 2022. Historical flood events during 2009 through 2019 were obtained from the Dartmouth Flood Observatory. The main outcome was diarrhea prevalence among children younger than 5 years in the 2 weeks before the survey was conducted. Results were analyzed by binomial generalized linear mixed-effects logistic regression models with nested random intercepts for country and survey cluster. Among 639 250 children making up the complete data series (excluding 274 847 children with missing values for diarrhea or baseline characteristics), 6365 (mean [SD] age, 28.9 [17.2] months; 3214 boys [50.5%]; 3151 girls [49.5%]) were exposed to floods during the 8 weeks after a flood started. The prevalence of diarrhea was 13.2% (n = 839) among exposed children and 12.7% (n = 80 337) among unexposed children. Exposure to floods was associated with increased diarrhea risk, with the highest odds ratio (OR) observed during the second to fourth weeks after floods started (OR, 1.35; 95% CI, 1.05-1.73). When floods were stratified by severity and duration, significant associations were observed only for extreme floods (OR during the third to fifth weeks, 2.07; 95% CI, 1.37-3.11) or floods lasting more than 2 weeks (OR during the second to fourth weeks, 1.47; 95% CI, 1.13-1.92), with significantly stronger associations than for less extreme floods or shorter-duration floods, respectively. The OR during the first 4 weeks after the start of floods was significantly higher for floods preceded by a 6-month or longer drought (12-month drought OR, 1.96; 95% CI, 1.53-2.52) than for floods not preceded by a 6-month or longer drought (12-month drought OR, 1.00; 95% CI, 0.79-1.27). These findings suggest that floods, especially severe floods, long-duration floods, and floods preceded by drought, are associated with an increased risk of diarrhea among children younger than 5 years living in low- and middle-income countries. With the projected increasing frequency and intensity of floods and drought under climate change, greater collective efforts are needed to protect children's health from these compounding events.

Collection of cancer-specific data in population-based surveys in low- and middle-income countries: A review of the demographic and health surveys.

Population-based surveys, such as those conducted by the Demographic and Health Surveys (DHS) Programme, can collect and disseminate the data needed to inform cancer control efforts in a standardised and comparable manner. This review examines the DHS questionnaires, with the aim of describing and analysing how cancer-specific questions have been asked from the inception of the surveys to date. A systematic search of the DHS database was conducted to identify cancer-specific questions asked in surveys. Descriptive statistics were used to summarise the cancer-specific questions across survey years and countries. In addition, the framing and scope of questions were appraised. A total of 341 DHS surveys (including standard, interim, continuous and special DHS surveys) have been conducted in 90 countries since 1985, 316 of which have been completed. A total of 39 (43.3%) of the countries have conducted at least one DHS survey with one or more cancer-specific questions. Of the 316 surveys with available final reports and questionnaires, 81 (25.6%) included at least one cancer-specific question; 54 (17.1%) included questions specific to cervical cancer, 41 (13.0%) asked questions about breast cancer, and 8 (2.5%) included questions related to prostate cancer. Questions related to other cancers (including colorectal, laryngeal, liver, lung, oral cavity, ovarian and non-site-specific cancers) were included in 40 (12.6%) of the surveys. Cancer screening-related questions were the most commonly asked. The majority of the surveys included questions on alcohol and tobacco use, which are known cancer risk factors. The frequency of cancer-specific questions has increased, though unsteadily, since inception of the DHS. Overall, the framing and scope of the cancer questions varied considerably across countries and survey years. To aid the collection of more useful population-level data to inform cancer-control priorities, it is imperative to improve the scope and content of cancer-specific questions in future DHS surveys.

Chronic comorbid conditions and asthma exacerbation occurrence in a general population sample

Chronic comorbid conditions are common in adults with asthma, and some may influence a patient’s asthma exacerbation risk. We explored associations between eighteen chronic comorbid conditions and asthma exacerbation occurrence in adults with asthma in a cross-sectional study nested within a cohort study using data from the two-yearly US National Health and Nutrition Examination Survey (NHANES) program. Data of 2387 adults with self-reported doctor-diagnosed current asthma from the 2007 to 2018 NHANES surveys were selected. Investigated chronic comorbidities were: angina pectoris; congestive heart failure; coronary heart disease; depression; diabetes mellitus; soft and hard drug use; gastroesophageal reflux; gout; history of heart attack; history of stroke; hypercholesterolemia; hypertension; kidney failure; liver conditions; obesity; rheumatoid arthritis; and thyroid problems. Outcome was defined as asthma exacerbation category: no, moderate, or severe exacerbation(s) in the past year. Ordinal logistic regression analysis with correction for potential confounders was used to estimate odds ratios (OR) for moderate or severe exacerbations. Observed associations with increased severe asthma exacerbation occurrence were: obesity (OR = 1.67; 95% confidence interval 1.24, 2.26), and rheumatoid arthritis (OR = 1.55; 1.04, 2.30). History of stroke (OR = 1.95; 1.22, 3.11) and rheumatoid arthritis (OR = 1.33; 1.00, 1.75) showed associations with increased moderate exacerbation occurrence. Age-stratified analysis showed soft drug use, obesity, depression, thyroid problems, and rheumatoid arthritis to be associated with moderate and/or severe exacerbation occurrence in one or more 10-year age strata. In conclusion, several chronic comorbid conditions were associated with asthma exacerbation occurrence, which confirms but also complements previous studies. Our observations contribute to understanding exacerbation risk estimation and, ultimately, personalized asthma management.

An insight from National Family Health Surveys on changing trends in prevalence and knowledge regarding T.B. in India

Background/objectivesAddressing gaps in knowledge about T.B. is a vital component of T.B.'s elimination to achieve the End T.B. strategy by 2025 in India. The present study compares the correct knowledge regarding T.B. by analysis of the nationally-representative secondary data of NFHS-4 (2015–16) and NFHS-5 (2019–20) data in India. MethodsNFHS-4 and NFHS-5 secondary data on eleven T.B.-related questions analysis was done after seeking permission to use datasets from the Demographic and Health Surveys (DHS) program—sociodemographic details and Responses exported and analysed using M.S. Excel. Descriptive variables were represented as frequency and percentages. Z tests for proportions were used to compare and determine differences between NFHS-4 and NFHS-5 knowledge. Statistical significance was set at a p-value of <0.05. ResultsThe correct knowledge regarding T.B. significantly rose from 457,399 (56.3%) in NFHS-4 to 507,517 (61.4%) in NFHS-5. However, a significant increase in incorrect knowledge about the other modes of transmission of T.B. and T.B. courtesy stigma in households from 95,985 (13.4%) in 2015-16 to 113,978 (14.9%) in 2019-20 was observed. ConclusionsThe correct knowledge of T.B. has significantly increased from NFHS-4 (2015–16) to NFHS-5 (2019–20). However, there is a significant increase in incorrect knowledge regarding the modes of transmission and stigmatising attitudes towards T.B. through improvement in the communication efforts in the National T.B. Elimination Programme (NTEP).

Negative associations between folate and bacterial vaginosis in the NHANES 2001 to 2004

BackgroundBacterial vaginosis (BV) is one of the most common infections among women of reproductive age and accounts for 15–50% of infections globally. The role played by folate in the pathogenesis and progression of BV is poorly understood. The aim of this study was to investigate the association between serum folate, red blood cell (RBC) folate, and BV in American women.Methods1,954 participants from the 2001-2004 National Health and Nutrition Examination Survey (NHANES) program were included in this study. Multiple logistic regression was used to analyze the association between serum folate, RBC folate, and BV, and covariates including race, age, education level, and body mass index were used to construct adjusted models. Stratified analysis was used to explore the stability of the above associations in different populations.ResultsIn the present cross-sectional study, we found that serum folate and RBC folate were inversely associated with the risk of BV. In the fully adjusted model, the risk of BV was reduced by 35% (OR=0.65, 95% CI: 0.51~0.83, p=0.0007) in the highest serum folate group and 32% (OR=0.68, 95% CI: 0.53~0.87, p=0.0023) in the highest RBC folate group compared to the lowest group.ConclusionsThe results of this study indicated that serum folate and RBC folate were inversely associated with the risk of BV folate supplementation may play an important role in the prevention and management of BV.

Perception Towards Epidemiology of Human Immunodeficiency Virus or Acquired Immunodeficiency Syndrome Among Women of Reproductive Age: Analysis of Nationwide Surveys in India.

The knowledge of HIV prevention, attitudes towards people living with HIV (PLHIV), and beliefs in myths related to HIV/AIDS among women of reproductive age group in India hold immense importance. As this group is particularly vulnerable to HIV infection, having accurate knowledge about prevention methods is crucial to protect themselves and their partners. Positive attitudes towards PLHIV foster support, reduce stigma and encourage early testing and treatment. Additionally, debunking myths and misconceptions surrounding HIV/AIDS can help dispel fear and promote informed decision-making. Empowering women with comprehensive knowledge, fostering positive attitudes, and debunking myths can contribute to effective HIV prevention strategies, reduce transmission rates, and improve women's overall well-being in India. Our objective was to create a regression model to show disparities in knowledge of the prevention of HIV/AIDS, attitude towards people living with HIV/AIDS, and belief in myths among women in India with adjusted odds ratio (aOR) for different socio-demographic factors, and to determine if there are any significant changes in the aOR during both surveys. A comparative study using secondary data analysis of two complex sample surveys. Individual Recode files from datasets obtained from Demographic Health Surveys (DHS) Program were exported to STATA v17.0 MP by STATA Corp LLC. Dependent and independent variables were chosen based on a literature review and computed. The design-adjusted chi-square test was used to assess the association between variables. A multinomial logistic regression analysis was used to derive a model. The model assessment was performed using the Wald test after estimation. The age group of 15-19 years had the highest odds of having sufficient knowledge of the prevention of HIV/AIDS during both National Family Health Surveys (NFHS) (aOR: 1.98 during NFHS-4 and aOR: 1.80 during NFHS-5). No education group had the highest odds of negative attitudes towards people living with HIV/AIDS during both surveys (aOR: 4.85 during NFHS-4 and aOR: 2.69 during NFHS-5). Rural areas had higher odds of believing in myths related to HIV/AIDS during both surveys (aOR: 1.07 during NFHS-4 and aOR: 1.13 during NFHS-5). This research study sheds light on the significant relationship between demographic factors and knowledge, attitudes, and beliefs related to HIV/AIDS among women. Specifically, women in the lower age group, lacking education, and residing in rural areas exhibited substantial levels of inadequate knowledge regarding HIV/AIDS prevention. Furthermore, this group was also associated with higher proportions of negative attitudes towards people living with HIV/AIDS and a greater tendency to believe in myths associated with HIV/AIDS.

Conditional selection of multifactor evidence for the levels of anaemia among women of reproductive age group

The study aims at ascertaining the conditional selection of key indicators affecting severe, moderate, mild, and no anaemia levels for women of reproductive age in India. The secondary data for levels of anaemia and personal records of individuals collected for India from the 7th phase of District Health Survey program of the United States Agency for International Development data depository. The data was cleaned and summarised using frequency and percentages. Then the variables were tested for association with levels of anaemia using the Chi-square (χ2) test. The multinomial logistic regression model was employed to ascertain the key indicators through a conditional selection of reference categories. Results suggest that severe anaemia was significantly prevalent among women in the reproductive stage, especially among the 15–29 age groups. Secondary and higher education had a negative effect on the severity of severe, moderate, and mild anaemia. The poorest wealth index stratum had higher and more significant severe anaemia, and households with two adults of the opposite sex had a significant negative effect (β = −0.116, OR = 0.89, p < 0.001) on severe anaemia level while having a significant positive effect on moderate and mild anaemia. Rural households were associated negatively and significantly with moderate and mild anaemia, and nuclear household structures had a higher prevalence of severe anaemia. Therefore, these indicators across different levels of anaemia should be considered for a faster rate of reduction at the national level. Despite several initiatives by the public sector, the anaemia level has remained elevated among women of reproductive age. Education, wealth index, age, pregnancy, relationship structure, household structure, and place of residence were found to be key indicators for the level of anaemia. The significant variables will act as a crucial input to formulate cost-effective public interventions and finally encourage the faster reduction of anaemia levels.

Comprehensive evaluation of serum cotinine on human health: Novel evidence for the systemic toxicity of tobacco smoke in the US general population

BackgroundAccumulating epidemiological studies have demonstrated that smoking caused damage to human health. However, these studies almost focused on the individual smoking pattern rather than the toxic ingredients of tobacco smoke. Despite the exact accuracy of cotinine as a smoking exposure biomarker, there were few studies investigating the association between serum cotinine and human health. This study aimed to provide novel evidence about the harmful effect of smoking on systemic health from the perspective of serum cotinine. MethodsAll used data was acquired from 9 survey cycles (2003−2020) of the National Health and Nutrition Examination Survey (NHANES) program. The mortality information of participants was derived from the National Death Index (NDI) website. The disease status of participants, including respiratory, cardiovascular, and musculoskeletal diseases, was obtained from questionnaire surveys. The metabolism-related index, including obesity, bone mineral density (BMD), and serum uric acid (SUA), was obtained from examination data. Multiple regression methods, smooth curve fitting, and threshold effect models were used for association analyses. ResultsWith a total of 53,837 subjects included, we detected an L-shaped association between serum cotinine and obesity-related index, a negative association between serum cotinine and BMD, a positive association between serum cotinine and nephrolith and coronary heart disease (CHD), a threshold effect of serum cotinine on hyperuricemia (HUA), osteoarthritis (OA), chronic obstructive pulmonary disease (COPD), and stroke, as well as a positive saturate effect of serum cotinine on asthma, rheumatoid arthritis (RA), all-cause, cardiovascular disease (CVD)-cause, cancer-cause, and diabetes-cause mortality. ConclusionsIn this study, we investigated the association between serum cotinine and multiple health outcomes, indicating the systematic toxicity of smoking exposure. These findings provided novel epidemiological evidence about how passive exposure to tobacco smoke affects the health condition of the general US population.

Assessing the combined effect of household cooking fuel and urbanicity on acute respiratory symptoms among under-five years in sub-Saharan Africa

BackgroundThis study sought to investigate the association between urbanicity (rural-urban residency), the use of solid biomass cooking fuels and the risk of Acute Respiratory Infections (ARIs) among children under the age of 5 in sub-Saharan Africa (SSA). MethodsCross-sectional data from the most recent surveys of the Demographic and Health Survey Program conducted in 31 sub-Saharan African countries were pooled for the analysis. The outcome variables, cough and rapid short breath were derived from questions that asked mothers if their children under the age of 5 suffered from cough and short rapid breath in the past two weeks preceding the survey. To examine the associations, multivariable negative log-log regression models were fitted for each outcome variable. ResultsHigher odds ratios of cough occurred among children in urban households that use unclean cooking fuel (aOR = 1.05 95% CI = 1.01, 1.08). However, lower odds ratios were observed for rural children in homes that use clean cooking fuel (aOR = 0.93 95% CI = 0.87, 0.99) relative to children in urban homes using clean cooking fuel. We also found higher odds ratios of short rapid breaths among children in rural households that use unclean cooking fuel compared with urban residents using clean cooking fuel (aOR = 1.12 95% CI = 1.08, 1.17). ConclusionUrbanicity and the use of solid biomass fuel for cooking were associated with an increased risk of symptoms of ARIs among children under five years in SSA. Thus, policymakers and stakeholders need to design and implement strategies that minimize children’s exposure to pollutants from solid biomass cooking fuel. Such interventions could reduce the burden of respiratory illnesses in SSA and contribute to the realization of Sustainable Development Goal 3.9, which aims at reducing the number of diseases and deaths attributable to hazardous chemicals and pollution of air, water and soil.

Socio-Economic Inequalities in the Double Burden of Malnutrition among under-Five Children: Evidence from 10 Selected Sub-Saharan African Countries

Africa is unlikely to end hunger and all forms of malnutrition by 2030 due to public health problems such as the double burden of malnutrition (DBM). Thus, the aim of this study is to determine the prevalence of DBM and degree of socio-economic inequality in double burden of malnutrition among children under 5 years in sub-Saharan Africa. This study used multi-country data collected by the Demographic and Health Surveys (DHS) Program. Data for this analysis were drawn from the DHS women's questionnaire focusing on children under 5 years. The outcome variable for this study was the double burden of malnutrition (DBM). This variable was computed from four indicators: stunting, wasting, underweight and overweight. Inequalities in DBM among children under 5 years were measured using concentration indices (CI). The total number of children included in this analysis was 55,285. DBM was highest in Burundi (26.74%) and lowest in Senegal (8.80%). The computed adjusted Erreygers Concentration Indices showed pro-poor socio-economic child health inequalities relative to the double burden of malnutrition. The DBM pro-poor inequalities were most intense in Zimbabwe (-0.0294) and least intense in Burundi (-0.2206). This study has shown that across SSA, among under-five children, the poor suffer more from the DBM relative to the wealthy. If we are not to leave any child behind, we must address these socio-economic inequalities in sub-Saharan Africa.

The Increase in Hemoglobin Concentration With Altitude Differs Between World Regions and Is Less in Children Than in Adults.

To compensate for decreased oxygen partial pressure, high-altitude residents increase hemoglobin concentrations [Hb]. The elevation varies between world regions, posing problems in defining cutoff values for anemia or polycythemia. The currently used altitude adjustments (World Health Organization [WHO]), however, do not account for regional differences. Data from The Demographic and Health Survey (DHS) Program were analyzed from 32 countries harboring >4% of residents at altitudes above 1000 m. [Hb]-increase, (ΔHb/km altitude) was calculated by linear regression analysis. Tables show 95% reference intervals (RIs) for different altitude ranges, world regions, and age groups. The prevalence of anemia and polycythemia was calculated using regressions in comparison to WHO adjustments. The most pronounced Δ[Hb]/km was found in East Africans and South Americans while [Hb] increased least in South/South-East Asia. In African regions and Middle East, [Hb] was decreased in some altitude regions showing inconsistent changes in different age groups. Of note, in all regions, the Δ[Hb]/km was lower in children than in adults, and in the Middle East, it was even negative. Overall, the Δ[Hb]/km from our analysis differed from the region-independent adjustments currently suggested by the WHO resulting in a lower anemia prevalence at very high altitudes. The distinct patterns of Δ[Hb] with altitude in residents from different world regions imply that one single, region-independent correction factor for altitude is not be applicable for diagnosing abnormal [Hb]. Therefore, we provide regression coefficients and reference-tables that are specific for world regions and altitude ranges to improve diagnosing abnormal [Hb].

Estimating the prevalence of exclusive breastfeeding with data from household surveys: Measurement issues and options.

The importance of breastfeeding for infant and maternal health is well established. The World Health Organization recommends that all infants be exclusively breastfed until they reach 6 months of age. The standard indicator to measure adherence to this criterion is the percentage of children aged 0-5 months who are currently being exclusively breastfed. This paper proposes supplementary measures that are easily calculated with existing survey data. First, for an accurate assessment of the WHO recommendation, we estimate the percentage of infants who are being exclusively breastfed at the exact age of 6 months. Second, an adjustment is proposed for prelacteal feeding. These two modifications, separately and in combination, are applied to data from 31 low-and middle-income countries that have participated in the Demographic and Health Surveys Program since 2015. There is considerable variation in the effects across countries. The modifications use existing data to provide a more accurate estimate than the standard indicator of the achievement of the exclusive breastfeeding until 6 months recommendation.

The declining trend in HIV prevalence from population-based surveys in Cameroon between 2004 and 2018: myth or reality in the universal test and treat era?

BackgroundHIV remains an epidemic of major public health importance in Cameroon but a decline in HIV prevalence has been observed according to population-based surveys conducted in 2004, 2011 and 2018. We sought to review current evidence for declining HIV prevalence despite increasing survival owing to ‘universal test and treat’ and to explore the reason for the decrease, particularly the role of behavioural change.MethodsWe conducted a secondary analysis using HIV prevalence, behavioural and social determinants data of the Demographic and Health Survey Program databases. Trend lines were fitted to data that were available for a minimum of three points in time during the 1991–2018 period. Regression coefficients associated p-values and 95% confidence intervals were obtained using Microsoft Excel software.ResultsOverall adult HIV prevalence decreased significantly from 5.4% (95%CI: 4.8-6.0) in 2004 to 4.3% (95%CI: 3.8–4.8) in 2011 and further down to 2.7% (95%CI: 2.3–3.1) in 2018 at a rate of about 1.4% every septennium (β = -1.4, R² = 0.98, p = 0.03). Yet, the number of persons surviving with HIV increased from about 0.05 million in 1991 to 0.5 million in 2018 corresponding to an increase in access to antiretroviral therapy from less than 10% to universal coverage of 80% respectively. Concurrent reductions in risky sexual behaviours were observed: a delayed sexual debut by one year, decreased sexual violence by 7%, decreased polygamous unions by 16%, decreased multiple sexual partners by 15.3% and increased condom use by 26.3%.ConclusionThe observed decline in HIV prevalence is statistically valid and reflects the observed decline in risky sexual behaviour that need to be sustained by the National HIV programme. Though universal access to ART has increased the number of persons surviving with HIV, this has not led to an increased prevalence of HIV in a setting with a rising population.

Temperature variability and birthweight: Epidemiological evidence from Africa

BackgroundMounting evidence supports an association between nonoptimal ambient temperatures (i.e., heat or cold) and risk of low birthweight (LBW) (<2500 g), while the effect of temperature variability (TV) is largely unknown. We aimed to quantify the association between TV and risk of LBW in Africa. MethodsData on birthweight in 37 countries during 1990–2020 were collected from the Demographic and Health Surveys program. We calculated overall, intraday, and interday TV during the entire pregnancy and each trimester using hourly temperatures at ∼ 9 km resolution from ERA5-Land. We employed generalized linear mixed logistic regression, with random effects for country and survey cluster, to quantify the association between LBW and three separate TV metrics. ResultsIn total there were 33,863 (10.2%) LBW births out of 333,618 records. We found a J-shaped association between TV and LBW. Compared to the reference TV where the lowest risk was observed, extremely high (97.5th percentile) overall, intraday, and interday TV during the entire pregnancy increased the odds of LBW birth by 37.3% (26.7–48.8%), 24.1% (16.4–32.3%), and 15.1% (6.9–24.0%), respectively. In total, 7.3% of all LBW births in Africa were attributable to elevated overall TV. These associations were observed in dry climate zones, but not in tropical or temperate zones. ConclusionsOur study suggests an adverse impact of TV on the risk of LBW in Africa, according to three different TV definitions, underlining the significance of climate-health risk assessment in those most vulnerable to climate change.

Model selection and optimization for poverty prediction on household data from Cambodia

Addressing global poverty requires understanding of the most poverty-stricken regions. One approach towards achieving this is through poverty prediction, a task that entails classifying poverty levels of households using available data. While machine learning (ML) has been applied in numerous fields with considerable success, its application in poverty prediction using exclusively household survey data is yet to be thoroughly explored. Household survey data offers a detailed view into the living conditions, lifestyle, and socio-economic factors affecting households. Hence, we aim explore the use of this data type in predicting poverty levels. Our study primarily focuses on three ML models: softmax classification, random forest classification, and multilayer perceptron (MLP). We chose Cambodia for this study due to its unique socio-economic landscape and as a representative of developing nations struggling with poverty. This analysis will serve as the foundation for applying this approach to other nations. The analysis was based on a dataset consisting of 15,825 household samples and 1,873 features obtained through the Demographic and Health Surveys (DHS) program in Cambodia. The study's aim was to validate the effectiveness of ML in poverty prediction using household data and identify the best performing model among the selected three. We hypothesized that the MLP, due to its advanced neural network structure, would provide superior results compared to the softmax classification and random forest models. As anticipated, the multilayer perceptron outperformed the other models, achieving an accuracy of 87% against the 81% and 80% accuracy of the random forest and softmax classification models respectively.