Precipitation variability and risk of infectious disease in children under 5 years for 32 countries: a global analysis using Demographic and Health Survey data

Assessment of water scarcity as a risk factor for cholera outbreaks

INTRODUCTION

Increasing aridity and incidence of droughts pose a significant threat to human health, primarily in exacerbating water scarcity, and is projected to become more frequent and severe as a result of related environmental changes in many regions globally. Concomitantly, water scarcity will force populations to utilize potentially contaminated water sources, hence increasing exposure to waterborne diseases, notably cholera. Proliferation of Vibrio cholerae, causative agent of cholera, is driven by environmental factors. Notably, temperature and precipitation have been employed in providing predictive awareness of cholera, allowing early warning and mitigation. The impact of droughts on incidence and spread of cholera is less understood.

METHODS

This study aimed to quantify relationships among temperature, precipitation, and droughts as a basis for establishing the connection of environmental parameters and outbreaks of cholera. Thirteen cholera outbreaks between 2003 and 2023 in four African countries (Ethiopia, Kenya, Nigeria, and Senegal) were assessed using odds ratio and k-means clustering analysis.

RESULTS

Cholera outbreaks were 3.07 (95 % CI: [0.95, 9.88]) times more likely when drought conditions (negative precipitation anomalies, positive temperature anomalies, and negative Standardized Precipitation-Evapotranspiration Index) were present, compared to their absence. When excess rainfall was also considered, the odds ratio increased to 3.50 (95 % CI: [1.03, 11.90]). Complementary evidence obtained using k-means clustering analysis supported the conclusion that outbreaks of cholera were common during drought conditions.

CONCLUSIONS

Considering the last few decades with increased severity and frequency of droughts in cholera-impacted regions, climate projections indicate the threat of cholera outbreaks will continue, especially noting increasing reports of cholera globally. Hence, predictive intelligence systems for rapid risk assessment, with respect to climate, drought, and human health, are warranted.

Temperature and precipitation affect the water fetching time burden in Sub-Saharan Africa

In Sub-Saharan Africa (SSA), over 75% of households lack on-premises water access, requiring residents to spend time walking to collect water from outside their homes - a time burden that falls disproportionately on women and girls. Climate change is predicted to alter precipitation and temperature patterns in SSA, which could impact household water access. Here, we use spatial first differences to assess the causal effects of weather on water fetching walk time using household survey data (n = 979,759 observations from 31 countries) merged with geo- and temporally-linked precipitation and temperature data over time periods ranging from 7 to 365 days. We find increases in precipitation reduce water fetching times; a 1 cm increase in weekly rainfall over the past year decreases walking time by 3.5 min. Higher temperatures increase walk times, with a 1°C increase in temperature over the past year increasing walking time by 0.76 min. Rural household water fetching times are more impacted by recent weather compared to urban households; however, electricity access in rural communities mitigates the effect. Our findings suggest that future climate change will increase the water fetching burden in SSA, but that co-provision of electricity and water infrastructure may be able to alleviate this burden.

How climate change is shaping young people's health: a participatory, youth co-led study from Bangladesh, Guatemala and Nigeria

INTRODUCTION

Climate change is shaping adolescent and young people's (AYP) transitions to adulthood with significant and often compounding effects on their physical and mental health. The climate crisis is an intergenerational inequity, with the current generation of young people exposed to more climate events over their lifetime than any previous one. Despite this injustice, research and policy to date lacks AYP's perspectives and active engagement.

METHODS

Participatory, youth co-led qualitative focus group discussions were held in Bangladesh, Guatemala and Nigeria in mid-2023. A total of 196 AYP ages 12-25 years participated. Open-ended questions elicited responses regarding AYP knowledge, experiences and perceptions of climate change. Using NVivo software, translated transcripts were coded to explore and synthesise key thematic areas.

RESULTS

Respondents discussed varied climate exposures and associated health risks, for example, how flooding events were impeding access to sexual and reproductive health commodities. Acute climate events like flooding and cyclones increased perceived risk of early marriage and gender-based violence in Bangladesh and Guatemala. In Nigeria, respondents discussed health effects of extreme heat, and how droughts were shifting women into more traditionally male roles in agriculture and income-generating activities, increasing the perceived risk of household tensions and gender-based violence. Commonly reported themes included perceived climate impacts on sexual and reproductive health including early marriage or gender-based violence. Another common theme was anxiety about climate change, its effects on economic and food insecurity in communities and feeling hopeless, lacking agency and not feeling supported by local institutions, all linked with worse mental health.

CONCLUSION

Our results summarise how AYP perceive climate change is affecting their physical and mental health, finding similarities and differences across these three settings. Our results can inform the development of policies and programmes that directly address AYP needs in a way that is inclusive and responsive.

Youth suicidality risk relative to ambient temperature and heatwaves across climate zones: A time series analysis of emergency department presentations in New South Wales, Australia

OBJECTIVE

Youth suicidality prevalence continues to rise alongside hot weather severity. Links between these two variables are underexplored. We examined associations between daily temperature and emergency department suicidality presentations by young people. We assessed these associations for five regions covering New South Wales as determined by 'climate zone' and analysed for heatwave effects as well as based on demographic subgroups.

METHODS

Daily emergency department presentations for suicidality by people aged 12-24 years across New South Wales, Australia, during warmer months (November to March) from 2012 to 2019 were examined in relation to daily mean temperature and heatwaves (⩾3 consecutive days ⩾ 95th percentile of long-term daily mean temperature) and by climate zone, using a generalised additive model with negative binomial distribution. Risks for age- and sex-based subgroups were also calculated.

RESULTS

New South Wales youth suicidality presentation rates were significantly higher on hotter days. For every 1°C rise above average daily mean temperature, youth suicidality presentations to New South Wales emergency departments increased by 1.3%. Heatwaves did not increase presentation rates beyond single-day daily mean temperature effects. These findings were predominantly replicated across climate zones and demographic subgroups, though the association between suicidality and ambient temperature was weaker in coastal regions including Eastern Sydney.

CONCLUSION

There is a positive linear association between ambient temperature and youth suicidality presentations to emergency departments. Risks are increased on single hot days, not only during heatwaves. Public health, broader societal approaches to heat and health system planning should consider impacts on youth suicidality of predicted increases in hot weather severity and frequency.

The Associations of Long-Term Temperature and Precipitation with Chronic Respiratory Symptoms: Projections for the Changing Climate

PURPOSE

To clarify the associations of climatic indices with chronic respiratory symptoms, with a final aim to approximate the effects of climate change on them.

METHODS

An e-mail survey was directed to the members of the Finnish Pensioners` Federation. The mean 20-years' precipitation and temperature in each subjects' home municipality were obtained from the Finnish Meteorological Institute, separately for summer and winter. Adjusted multivariate models were utilized to investigate the associations of the climatic indices with chronic rhinosinusitis, chronic cough, wheezing with dyspnea, and sleep apnea.

RESULTS

There were 6189 responders from 283 municipalities. Chronic rhinosinusitis and chronic cough were most prevalent in the southeastern regions of the country, where the precipitation counts were highest. In the multivariate models, winter precipitation in the home municipality increased the risks of chronic rhinosinusitis and chronic cough [adjusted OR 1.80 (1.30-2.51) per 100 mm, p < 0.001, and 1.57 (1.19-2.07) per 100 mm, p = 0.001, respectively]. Wheezing with dyspnea and sleep apnea were not associated with the climatic indices.

CONCLUSION

Chronic rhinosinusitis and chronic cough were associated with long-term winter precipitation. Given the anticipated increase in winter precipitation in Northern America and Northern Europe, the prevalences of chronic rhinosinusitis and chronic cough may increase there.

El Niño southern oscillation, weather patterns, and bacillary dysentery in the Yangtze River Basin, China

BACKGROUND

Increasingly intense weather anomalies associated with interannual climate variability patterns, like El Niño-southern oscillation (ENSO), could exacerbate the occurrence and transmission of infectious diseases. However, research in China remains limited in understanding the impacts and intermediate weather changes of ENSO on bacillary dysentery (BD). This study aimed to reveal the relationship between ENSO, weather conditions, and the incidence of BD, and to identify the potential meteorological pathways moderated by ENSO in the ENSO-BD connections.

METHODS

BD disease data and meteorological data, as well as ENSO index, from 2005 to 2020 were obtained for 95 cities in the Yangtze River Basin. We first established the associations between ENSO events and BD, ENSO and weather, as well as weather and BDs using two-stage statistical models. Then, we applied a causal mediation analysis to identify the specific meteorological changes in the ENSO-BD relationship.

RESULTS

In the Yangtze River Basin, both El Niño (IRR: 1.06, 95%CI: 1.04 ~ 1.08) and La Niña (IRR: 1.03, 95%CI: 1.02 ~ 1.05) events were found to increase the risk of BD. Variations of ENSO index were associated with changes in local weather conditions. Both the increases in regional temperatures and rainfall were associated with a higher risk of BD. In the casual mediation analyses, we identified that higher temperatures and excessive rainfall associated with La Niña and El Niño events mediated the ENSO's effect on BD, with mediation proportions of 38.58% and 34.97%, respectively.

CONCLUSIONS

Long-term climate variability, like ENSO, can affect regional weather conditions and lead to an increased risk of BD. We identified the mediating weather patterns in the relationship between ENSO and BD, which could improve targeted health interventions and establish an advanced early warning system in response to the BD epidemic.

Determinants of diarrhoeal diseases among under-five children in Africa (2013-2023): a comprehensive systematic review highlighting geographic variances, socioeconomic influences, and environmental factors

BACKGROUND

Diarrhea diseases continue to present a significant threat to the well-being of children under the age of five in Africa, thereby contributing substantially to both morbidity and mortality rates. The period spanning between January 2013 and December 2023 has witnessed persistent challenges in the fight against these diseases, thereby necessitating a thorough investigation into the factors that determine their occurrence. It is important to note that the burden of diarrhea diseases is not evenly distributed across the continent, with residence, socioeconomic, and environmental factors playing pivotal roles in shaping the prevalence and incidence rates. Consequently, this systematic review aimed to consolidate and analyze the existing body of literature on the determinants of diarrhea diseases among children under the age of five in Africa between January 2013 and December 2023.

METHOD

The systematic review employed a rigorous methodological approach to examine the determinants of diarrhea diseases among children under the age of five in Africa between January 2013 and December 2023. A comprehensive search strategy was implemented, utilizing databases such as PubMed, Scopus, and Web of Science, and incorporating relevant keywords. The inclusion criteria focused on studies published within the specified timeframe, with a specific focus on the determinants of diarrhea disease among children under the age of five in Africa. The study selection process involved a two-stage screening, with independent reviewers evaluating titles, abstracts, and full texts to determine eligibility. The quality assessment, employing a standardized tool, ensured the inclusion of studies with robust methodologies. Data extraction encompassed key study details, including demographics, residence factors, socioeconomic influences, environmental variables, and intervention outcomes.

RESULTS

The search yielded a total of 12,580 articles across 25 African countries; however, only 97 of these articles met the inclusion criteria and were ultimately included in the systematic review. The systematic review revealed geographic and seasonal disparities in the prevalence of diarrhoeal diseases across different countries in Africa. Factors such as age-related vulnerabilities, gender disparities, maternal occupation, disposal of young children's stools, and economic status were identified as significant determinants of the prevalence of diarrhea disease.

CONCLUSION

This systematic review provides a comprehensive understanding of the determinants of diarrhea diseases among children under the age of five in Africa between January 2013 and December 2023. The nuanced analysis of residence variations, socioeconomic influences, environmental factors, and intervention outcomes underscores the complex nature of this issue. The findings highlight the necessity for region-specific and context-sensitive interventions to address the unique challenges faced by diverse communities. This review serves as a valuable resource for policymakers, healthcare professionals, and researchers, guiding the development of evidence-based strategies aimed at reducing the burden of diarrhea diseases and improving child health outcomes in Africa.

The association between climatic factors and waterborne infectious outbreaks with a focus on vulnerability in Pakistan: integrative review

Climate change affects the spread of waterborne infectious diseases, yet research on vulnerability to outbreaks remains limited. This integrative review examines how climate variables (temperature and precipitation) relate to human vulnerability factors in Pakistan. By 2060, mean temperatures are projected to rise from 21.68°C (2021) to 30°C, with relatively stable precipitation. The epidemiological investigation in Pakistan identified Diarrhea (119,000 cases/year), Malaria (2.6 million cases/year), and Hepatitis (A and E) as the most prevalent infections. This research highlighted vulnerability factors, including poverty (52% of the population), illiteracy (59% of the population), limited healthcare accessibility (55% of the population), malnutrition (38% of the population), dietary challenges (48% of the population), as well as exposure to water pollution (80% of the population) and air pollution (55% of the population). The findings suggest that the coordinated strategies are vital across health, environmental, meteorological, and social sectors, considering climatic variability patterns and population vulnerability determinants.

Exploring the determinants of under-five mortality and morbidity from infectious diseases in Cambodia-a traditional and machine learning approach

Cambodia has made progress in reducing the under-five mortality rate and burden of infectious diseases among children over the last decades. However the determinants of child mortality and morbidity in Cambodia is not well understood, and no recent analysis has been conducted to investigate possible determinants. We applied a multivariable logistical regression model and a conditional random forest to explore possible determinants of under-five mortality and under-five child morbidity from infectious diseases using the most recent Demographic Health Survey in 2021-2022. Our findings show that the majority (58%) of under-five deaths occurred during the neonatal period. Contraceptive use of the mother led to lower odds of under-five mortality (0.51 [95% CI 0.32-0.80], p-value 0.003), while being born fourth or later was associated with increased odds (3.25 [95% CI 1.09-9.66], p-value 0.034). Improved household water source and higher household wealth quintile was associated with lower odds of infectious disease while living in the Great Lake or Coastal region led to increased odds respectively. The odds ratios were consistent with the results from the conditional random forest. The study showcases how closely related child mortality and morbidity due to infectious disease are to broader social development in Cambodia and the importance of accelerating progress in many sectors to end preventable child mortality and morbidity.

Space-time distribution of intestinal infectious diseases and their association with socioeconomic variables in Ecuador

Background

Intestinal infectious diseases are a global concern in terms of morbidity, and they are closely linked to socioeconomic variables such as quality of life, weather and access to healthcare services. Despite progress in spatial analysis tools and geographic information systems in epidemiology, studies in Ecuador that evaluate temporal trends, specific geographic groups, and their correlation with socioeconomic variables are lacking. The absence of such information makes it challenging to formulate public health policies. This study sought to identify the spatial and temporal patterns of these diseases in Ecuador, along with their correlation with socioeconomic variables.

Methods

In Ecuador, the study was carried out in a continental territory, focusing on data related to intestinal infectious diseases collected from the National Institute of Statistics and Census (Instituto Nacional de Estadística y Censos) during the period from 2014 to 2019. This study involved spatial and temporal analyses using tools such as the global Moran's index and Local Indicators of Spatial Association to identify spatial clustering patterns and autocorrelation. Additionally, correlations between morbidity rates and socioeconomic variables were examined.

Results

During the investigated period, Ecuador registered 209,668 cases of these diseases. Notable variations in case numbers were identified, with a 9.2% increase in 2019 compared to the previous year. The most impacted group was children under 5 years old, and the highest rates were centered in the southern and southwestern regions of the country, with Limón Indanza and Chunchi being the cantons with the highest rates, notably showing a significant increase in Limón Indanza. Additionally, there were significant correlations between morbidity rates and socioeconomic variables, school dropout rates, low birth weight, and access to water services.

Conclusion

This study emphasizes the importance of considering socioeconomic variables when addressing these diseases in Ecuador. Understanding these correlations and geospatial trends can guide the development of health policies and specific intervention programs to reduce the incidence in identified high-risk areas. More specific research is needed to understand the underlying causes of variability in morbidity and develop effective prevention strategies.

Rainfall and Temperature Influences on Childhood Diarrhea and the Effect Modification Role of Water and Sanitation Conditions: A Systematic Review and Meta-Analysis

The latest report from the Intergovernmental Panel on Climate Change (IPCC) highlighted the worsening impacts of climate change. Two climate factors-temperature and rainfall uncertainties-influence the risk of childhood diarrhea, which remains a significant cause of morbidity and mortality in low- and middle-income countries. They create a conducive environment for diarrhea-causing pathogens and overwhelm environmental prevention measures. This study aimed to produce comprehensive evidence on the association of temperature and rainfall variability with the risk of childhood diarrhea and the influence of water and sanitation conditions on those associations. We conducted a systematic review and meta-analysis using the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) approach. Records published in English from 2006 to 2023 were searched on 8 January 2024 via PubMed, EMBASE, ScienceDirect, Scopus, the Cochrane Library, and Google/Google Scholar using comprehensive search terms. We assessed studies for any risk of bias using the Navigation Guide and rated the quality of the evidence using the GRADE approach. The heterogeneity among estimates was assessed using I-squared statistics (I2). The findings of the analysis were presented with forest plots using an incidence rate ratio (IRR). A meta-analysis was conducted on effect modifiers (water supply and sanitation conditions) using a random effects model with a 95% confidence interval (CI). The statistical analyses were conducted using R 4.3.2 software and Review Manager 5.3. A total of 2017 records were identified through searches, and only the 36 articles that met the inclusion criteria were included. The analysis suggests a small positive association between increased temperature and the occurrence of under-five diarrhea, with the pooled IRR = 1.04; 95% CI [1.03, 1.05], at I2 = 56% and p-value < 0.01, and increased rainfall and U5 diarrhea, with IRR = 1.14; 95% CI [1.03, 1.27], at I2 = 86% and p-value < 0.01. The meta-analysis indicated a positive association between unimproved latrine facilities and drinking water sources with a rainfall-modified effect on U5 diarrhea, with IRR = 1.21; 95% CI [0.95, 1.53], at I2 = 62% and p-value = 0.03. We found that an increase in mean temperature and rainfall was associated with an increased risk of childhood diarrhea. Where there were unimproved latrine facilities and drinking water sources, the increase in mean rainfall or temperature would increase the incidence of childhood diarrhea. The results of this review help in assessing the effectiveness of current intervention programs, making changes as needed, or creating new initiatives to lower the prevalence of childhood diarrhea.

Influence of hydrometeorological risk factors on child diarrhea and enteropathogens in rural Bangladesh

BACKGROUND

A number of studies have detected relationships between weather and diarrhea. Few have investigated associations with specific enteric pathogens. Understanding pathogen-specific relationships with weather is crucial to inform public health in low-resource settings that are especially vulnerable to climate change.

OBJECTIVES

Our objectives were to identify weather and environmental risk factors associated with diarrhea and enteropathogen prevalence in young children in rural Bangladesh, a population with high diarrheal disease burden and vulnerability to weather shifts under climate change.

METHODS

We matched temperature, precipitation, surface water, and humidity data to observational longitudinal data from a cluster-randomized trial that measured diarrhea and enteropathogen prevalence in children 6 months-5.5 years from 2012-2016. We fit generalized additive mixed models with cubic regression splines and restricted maximum likelihood estimation for smoothing parameters.

RESULTS

Comparing weeks with 30°C versus 15°C average temperature, prevalence was 3.5% higher for diarrhea, 7.3% higher for Shiga toxin-producing Escherichia coli (STEC), 17.3% higher for enterotoxigenic E. coli (ETEC), and 8.0% higher for Cryptosporidium. Above-median weekly precipitation (median: 13mm; range: 0-396mm) was associated with 29% higher diarrhea (adjusted prevalence ratio 1.29, 95% CI 1.07, 1.55); higher Cryptosporidium, ETEC, STEC, Shigella, Campylobacter, Aeromonas, and adenovirus 40/41; and lower Giardia, sapovirus, and norovirus prevalence. Other associations were weak or null.

DISCUSSION

Higher temperatures and precipitation were associated with higher prevalence of diarrhea and multiple enteropathogens; higher precipitation was associated with lower prevalence of some enteric viruses. Our findings emphasize the heterogeneity of the relationships between hydrometeorological variables and specific enteropathogens, which can be masked when looking at composite measures like all-cause diarrhea. Our results suggest that preventive interventions targeted to reduce enteropathogens just before and during the rainy season may more effectively reduce child diarrhea and enteric pathogen carriage in rural Bangladesh and in settings with similar meteorological characteristics, infrastructure, and enteropathogen transmission.

Multidrug-resistant pathogens contaminate river water used in irrigation in disenfranchised communities

OBJECTIVES

The contamination of fresh surface waters poses a significant burden on human health and prosperity, especially in marginalized communities with limited resources and inadequate infrastructure. Here, we performed in-depth genomic analyses of multidrug-resistant bacteria (MDR-B) isolated from Al-Oueik river water that is used for irrigation of agricultural fields in a disenfranchised area that also hosts a makeshift Syrian refugee camp.

METHODS

A composite freshwater sample was filtered. Faecal coliforms were counted and extended spectrum cephalosporins and/or ertapenem resistant bacteria were screened. Isolates were identified using MALDI-TOF-MS and analysed using whole-genome sequencing (WGS) to identify the resistome, sequence types, plasmid types, and virulence genes.

RESULTS

Approximately 106 CFU/100 mL of faecal coliforms were detected in the water. Four drug-resistant Gram-negative bacteria were identified, namely Escherichia coli, Klebsiella pneumoniae, Enterobacter hormaechei, and Pseudomonas otitidis. Notably, the E. coli isolate harboured blaNDM-5 and a YRIN-inserted PBP3, representing an emerging public health challenge. The K. pneumoniae isolate carried blaSHV-187 as well as mutations in the gene encoding the OmpK37 porin. Enterobacter hormaechei and P. otitidis harboured blaACT-16 and blaPOM-1, respectively.

CONCLUSION

This report provides comprehensive genomic analyses of MDR-B in irrigation water in Lebanon. Our results further support that irrigation water contaminated with faecal material can be a reservoir of important MDR-B, which can spread to adjacent agricultural fields and other water bodies, posing both public health and food safety issues. Therefore, there is an urgent need to implement effective water quality monitoring and management programs to control the proliferation of antibiotic-resistant pathogens in irrigation water in Lebanon.

Perceived barriers of access to health and nutrition services under drought and food insecurity emergency in north-east Uganda: a qualitative study

BACKGROUND

In the face of drought and food insecurity emergency, evidence on access to health and nutrition services is important. Karamoja is one of the regions that have experienced extreme drought and food insecurity emergency in Uganda. As a part of the drought and food insecurity emergency response, World Health Organization (WHO) with Ministry of Health (MoH) has designed and implemented a qualitative study in 15 districts that have experienced drought and food insecurity emergency in north-east Uganda. Thus, we aimed to explore the barriers of access to health and nutrition services in drought and food insecurity emergency affected districts in north-east Uganda.

METHODS

We employed a descriptive qualitative study design. We interviewed 30 patients and 20 Village Health Teams (VHT) from 15 districts. We employed an in-depth interview with semi-structured questions to collect data until information saturation reached. We used thematic data analysis approach by ATLAS.ti version 7.5.1.8 software.

RESULTS

Of the 30 interviewed subjects, 15 were female, and the median age of the subjects was 29 years with interquartile range (IQR) of 23 to 37 years. Majority (68.8%) of subjects reported that access to health and nutrition services was harder to them. Four themes: sociocultural and economic; environmental; health system, and individual related factors were identified as the barriers of access to health and nutrition services.

CONCLUSION

The present study identified several modifiable barriers that hinder access to health and nutrition services in drought and food insecurity affected districts. Comprehensive interventions aimed at addressing sociocultural, economic, environmental, health system and subject related challenges are required to improve access to health and nutrition services in drought and food insecurity affected setups.

Estimating the burden of disease attributable to high ambient temperature across climate zones: methodological framework with a case study

BACKGROUND

With high temperature becoming an increasing health risk due to a changing climate, it is important to quantify the scale of the problem. However, estimating the burden of disease (BoD) attributable to high temperature can be challenging due to differences in risk patterns across geographical regions and data accessibility issues.

METHODS

We present a methodological framework that uses Köppen-Geiger climate zones to refine exposure levels and quantifies the difference between the burden observed due to high temperatures and what would have been observed if the population had been exposed to the theoretical minimum risk exposure distribution (TMRED). Our proposed method aligned with the Australian Burden of Disease Study and included two parts: (i) estimation of the population attributable fractions (PAF); and then (ii) estimation of the BoD attributable to high temperature. We use suicide and self-inflicted injuries in Australia as an example, with most frequent temperatures (MFTs) as the minimum risk exposure threshold (TMRED).

RESULTS

Our proposed framework to estimate the attributable BoD accounts for the importance of geographical variations of risk estimates between climate zones, and can be modified and adapted to other diseases and contexts that may be affected by high temperatures.

CONCLUSIONS

As the heat-related BoD may continue to increase in the future, this method is useful in estimating burdens across climate zones. This work may have important implications for preventive health measures, by enhancing the reproducibility and transparency of BoD research.