Hurricane flooding and acute gastrointestinal illness in North Carolina

Health Disparities in the Aftermath of Flood Events: A Review of Physical and Mental Health Outcomes with Methodological Considerations in the USA

PURPOSE OF REVIEW

This review applies an environmental justice perspective to synthesize knowledge of flood-related health disparities across demographic groups in the USA. The primary aim is to examine differential impacts on physical and mental health outcomes while also assessing methodological considerations such as flood exposure metrics, baseline health metrics, and community engagement.

RECENT FINDINGS

In our review (n = 27), 65% and 72% of studies identified racial, ethnic, or socio-economic disparities in physical and mental health outcomes post-flooding, respectively. The majority of racial/ethnic disparities were based on Black race, while most socio-economic disparities were based on lower household income. Forty-two percent of studies lacked flood exposure metrics, but often identified disparities. Common flood exposure metrics included self-reported flooding, flood risk models, and satellite-based observations. Seventy percent of studies lacked baseline health measurements or suitable alternatives, and only 19% incorporated community engagement into their research design. The literature consistently finds that both physical and mental health burdens following flooding are unequally shared across racial, ethnic, and socio-economic groups. These findings emphasize the need for disaster risk reduction policies that address underlying vulnerabilities to flooding, unequal exposure to flooding, and progressive funding for recovery efforts. Findings also underscore the importance of methodological enhancements to facilitate precise assessments of flood exposure and health outcomes.

Impact of extreme weather events on healthcare utilization and mortality in the United States

Climate change is intensifying extreme weather events. Yet a systematic analysis of post-disaster healthcare utilization and outcomes for severe weather and climate disasters, as tracked by the US government, is lacking. Following exposure to 42 US billion-dollar weather disasters (severe storm, flood, flood/severe storm, tropical cyclone and winter storm) between 2011 and 2016, we used a difference-in-differences (DID) approach to quantify changes in the rates of emergency department (ED) visits, nonelective hospitalizations and mortality between fee-for-service Medicare beneficiaries in affected compared to matched control counties in post-disaster weeks 1, 1-2 and 3-6. Overall, disasters were associated with higher rates of ED utilization in affected counties in post-disaster week 1 (DID of 1.22% (95% CI, 0.20% to 2.25%; P < 0.020)) through week 2. Nonelective hospitalizations were unchanged. Mortality was higher in affected counties in week 1 (DID of 1.40% (95% CI, 0.08% to 2.74%; P = 0.037)) and persisted for 6 weeks. Counties with the greatest loss and damage experienced greater increases in ED and mortality rates compared to all affected counties. Thus, billion-dollar weather disasters are associated with excess ED visits and mortality in Medicare beneficiaries. Tracking these outcomes is important for adaptation that protects patients and communities, health system resilience and policy.

Using Inundation Extents to Predict Microbial Contamination in Private Wells after Flooding Events

Disaster recovery poses unique challenges for residents reliant on private wells. Flooding events are drivers of microbial contamination in well water, but the relationship observed between flooding and contamination varies substantially. Here, we investigate the performance of different flood boundaries─the FEMA 100 year flood hazard boundary, height above nearest drainage-derived inundation extents, and satellite-derived extents from the Dartmouth Flood Observatory─in their ability to identify well water contamination following Hurricane Florence. Using these flood boundaries, we estimated about 2600 wells to 108,400 private wells may have been inundated─over 2 orders of magnitude difference based on boundary used. Using state-generated routine and post-Florence testing data, we observed that microbial contamination rates were 7.1-10.5 times higher within the three flood boundaries compared to routine conditions. However, the ability of the flood boundaries to identify contaminated samples varied spatially depending on the type of flooding (e.g., riverine, overbank, coastal). While participation in testing increased after Florence, rates were overall still low. With <1% of wells tested, there is a critical need for enhanced well water testing efforts. This work provides an understanding of the strengths and limitations of inundation mapping techniques, which are critical for guiding postdisaster well water response and recovery.

Determinants of Diarrhea Among Children Aged 1 to 6 Years in Flood-Affected Areas of Pakistan: A Cross-Sectional Study

Frequent floods can contribute to the spread of various diseases and complications, some of which may result in diarrhea, especially among children. The current study aimed to find the determinants of diarrhea among children aged 1-6 years in flood-affected areas in Khyber Pakhtunkhwa, Pakistan. A cross-sectional study was conducted in flood-affected districts. Data regarding sociodemographic information related to diarrhea and anthropometric data were collected through a validated questionnaire. Logistic regression was used to find the determinants of diarrhea. In the presence of diarrhea, the prevalences found of stunting, wasting, and being underweight were 75.2%, 76.5%, and 74.1%, respectively, which is higher than those in children without diarrhea (stunting, 24.8%; wasting, 23.5%; and being underweight, 25.9%). In bivariate regression, children aged 2-4 years (odds ratio [OR] = 1.65, P < 0.05), large family size (OR = 7.46, P < 0.01), low income (OR = 2.55, < 0.001), bathing in ponds (OR = 3.05, P < 0.05), drinking of untreated water (OR = 3, P < 0.05), flooding (OR = 1.8, P < 0.05), children living in mud houses (OR = 1.5, P < 0.05), and usage of utensils without lids (OR = 1.96, P < 0.001) were significantly associated with occurrence of diarrhea. In multivariate regression, the identified risk factors (P < 0.05) for diarrhea in flood-affected areas included illiterate mothers, flooding, large family size, households without livestock, poor water quality, untreated water, and lack of toilet facilities. In conclusion, addressing the determinants of diarrhea identified in this study is crucial for mitigating the impact of frequent floods on children in flood-affected areas. Moreover, the higher prevalence of malnutrition underscores the urgent need for comprehensive strategies and proper water, sanitation, and hygiene programs to reduce the occurrence and determinants of diarrhea.

Shifting terrains: Understanding residential contaminants after flood disasters

Flood disasters can induce the mass transport of soils and sediments. This has the potential to distribute contaminants and present novel combinations to new locations - including residential neighborhoods. Even when soil contaminants cannot be directly attributed to the disaster, data on bacterial and heavy metal(loids) can facilitate an environmentally just recovery by enabling reconstruction decisions that fill data gaps to minimize future exposure. These data-gathering interventions may be especially useful in poor, rural, and racially diverse communities where there is a high probability of exposure to multiple hazards and a potential dependency on the financial resources of disaster aid as a means of reducing chronic exposures to other environmental pollutants. At the same time, entering these post-disasters spaces is ethically complex. To acknowledge this complexity, we pilot a framework for work that gathers social-ecological hazard information while retaining a fair-minded approach to transdisciplinary work. Assembled a transdisciplinary team to recruit participants from 90 households subjected to flooding in the southeastern US. Participating households agreed to interviews to elicit flood experience and environmental health concerns, soil sampling for fecal bacteria (E. coli) and soil sampling for selected heavy metals and metalloids (Pb, As, Cd) at their flooded residence. Soil sampling found a wide range of E. coli concentrations in soil (0.4-1115.7 CFU/ dry gram). Heavy metal(loid)s were detected at most residences (As 97.9 %; Ca 25.5 %; Pb 100 %). Individually, heavy metal(loid) concentrations did not exceed regulatory thresholds. Hazard, risk, and mitigation concerns expressed during interviews reveal that integrated human-nature concepts complicate common understandings of how hazard perceptibility (smell, sight, touch, and information) affects research-action spaces. Qualitative analysis of interviews and field notes revealed that soil-related hazards addressed by our biophysical protocols were less salient than changes with direct causal associations with flooding. We conclude by discussing the potential for the social-ecological hazard information that is fair-minded and transdisciplinary (SHIFT) framework to advance environmentally just approaches to research-action spaces after disasters.

Respiratory and nervous system effects of a hydrogen sulfide crisis in Carson, California

BACKGROUND

In October 2021, many residents in Carson, California experienced malodors, headaches, and respiratory symptoms. Hydrogen sulfide (H2S), a toxic odorous gas, was measured in Carson at concentrations up to 7000 parts per billion (ppb) and remained above California's acute air quality standard of 30 ppb for about a month. Research on how low- and medium-level H2S exposure affects the respiratory and nervous systems has yielded conflicting results, and few studies have examined the effects of subacute H2S exposure.

METHODS

We calculated daily rates of emergency department (ED) visits with various respiratory and nervous systems diagnosis codes in Carson area ZIP codes (≤6 km from event's epicenter) and in Los Angeles County ZIP codes >15 km from event's epicenter (control area). Using controlled interrupted time series, we compared ED visit rates during the month of the H2S crisis in Carson to the predicted rates had the incident not occurred, based on 2018-2021 ED trends, and controlling for ED visit rate changes in the control area.

RESULTS

We observed a 24 % increase in ED visit rate for all respiratory system diseases (rate ratio = 1.24, 95 % CI: 1.16, 1.32), a 38 % increase for asthma (RR = 1.38, 95 % CI: 1.26, 1.50), a 26 % increase for acute upper respiratory infections (RR = 1.26, 95 % CI: 1.13, 1.38), a 21 % increase for dizziness (RR = 1.21, 95 % CI: 1.04, 1.38), and a 25 % increase for migraines and headaches (RR = 1.25, 95 % CI: 1.13, 1.36) in the Carson area during the first month of the H2S event compared to the expected rates.

CONCLUSIONS

This H2S crisis was associated with increased ED visit rates for multiple respiratory and nervous system outcomes. Reducing H2S exposure and improving to response during H2S episodes may improve public health.

Respond quickly and effectively! Components of the military health surveillance system in natural disasters: A qualitative study

BACKGROUND

The systematic collection, analysis, and interpretation of health data by health surveillance systems provide timely and comprehensive surveillance of public health, identification health priorities, and, consequently, a quick and timely response to reduce damage during natural disasters. Since military forces appear as first responders at the scene of accidents, the present study aimed to identify the components of the military health care system during natural disasters.

MATERIALS AND METHOD

Qualitative data collected through semi-structured interviews were analyzed via the conventional content analysis approach to identify the components of the military health care system in natural disasters. The participants consisted of 13 experts who were experienced in providing health services in the military and the civilian health care system during natural disasters in January 2022 to June 2022.

RESULT

The identified components were classified into four main categories, namely, pre-requisite components (comprehensive health care, defined position, and providing information), driving components (system efficiency, effective communication), operational components (contingent performance, effective response), and promotional components (purposeful support, pre-disaster preparation).

CONCLUSION

In conclusion, the military health surveillance system is a cooperative service for the national health system in which data is essential for making decisions on health and treatment measures during disasters. This study-by identifying four categories of the important components in the design, implementation, and development of the military health surveillance system-provides a comprehensive view of an appropriate and evidence-based military surveillance system in disasters.

Local and Environmental Reservoirs of Salmonella enterica After Hurricane Florence Flooding

In many regions of the world, including the United States, human and animal fecal genetic markers have been found in flood waters. In this study, we use high-resolution whole genomic sequencing to examine the origin and distribution of Salmonella enterica after the 2018 Hurricane Florence flooding. We specifically asked whether S. enterica isolated from water samples collected near swine farms in North Carolina shortly after Hurricane Florence had evidence of swine origin. To investigate this, we isolated and fully sequenced 18 independent S. enterica strains from 10 locations (five flooded and five unflooded). We found that all strains have extremely similar chromosomes with only five single nucleotide polymorphisms (SNPs) and possessed two plasmids assigned bioinformatically to the incompatibility groups IncFIB and IncFII. The chromosomal core genome and the IncFIB plasmid are most closely related to environmental Salmonella strains isolated previously from the southeastern US. In contrast, the IncFII plasmid was found in environmental S. enterica strains whose genomes were more divergent, suggesting the IncFII plasmid is more promiscuous than the IncFIB type. We identified 65 antibiotic resistance genes (ARGs) in each of our 18 S. enterica isolates. All ARGs were located on the Salmonella chromosome, similar to other previously characterized environmental isolates. All isolates with different SNPs were resistant to a panel of commonly used antibiotics. These results highlight the importance of environmental sources of antibiotic-resistant S. enterica after extreme flood events.

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

Importance

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.

Objective

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.

Design, Setting, and Participants

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.

Exposures

Historical flood events during 2009 through 2019 were obtained from the Dartmouth Flood Observatory.

Main Outcome and Measures

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.

Results

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).

Conclusions

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.

Mortality risks associated with floods in 761 communities worldwide: time series study

OBJECTIVE

To evaluate lag-response associations and effect modifications of exposure to floods with risks of all cause, cardiovascular, and respiratory mortality on a global scale.

DESIGN

Time series study.

SETTING

761 communities in 35 countries or territories with at least one flood event during the study period.

PARTICIPANTS

Multi-Country Multi-City Collaborative Research Network database, Australian Cause of Death Unit Record File, New Zealand Integrated Data Infrastructure, and the International Network for the Demographic Evaluation of Populations and their Health Network database.

MAIN OUTCOME MEASURES

The main outcome was daily counts of deaths. An estimation for the lag-response association between flood and daily mortality risk was modelled, and the relative risks over the lag period were cumulated to calculate overall effects. Attributable fractions of mortality due to floods were further calculated. A quasi-Poisson model with a distributed lag non-linear function was used to examine how daily death risk was associated with flooded days in each community, and then the community specific associations were pooled using random effects multivariate meta-analyses. Flooded days were defined as days from the start date to the end date of flood events.

RESULTS

A total of 47.6 million all cause deaths, 11.1 million cardiovascular deaths, and 4.9 million respiratory deaths were analysed. Over the 761 communities, mortality risks increased and persisted for up to 60 days (50 days for cardiovascular mortality) after a flooded day. The cumulative relative risks for all cause, cardiovascular, and respiratory mortality were 1.021 (95% confidence interval 1.006 to 1.036), 1.026 (1.005 to 1.047), and 1.049 (1.008 to 1.092), respectively. The associations varied across countries or territories and regions. The flood-mortality associations appeared to be modified by climate type and were stronger in low income countries and in populations with a low human development index or high proportion of older people. In communities impacted by flood, up to 0.10% of all cause deaths, 0.18% of cardiovascular deaths, and 0.41% of respiratory deaths were attributed to floods.

CONCLUSIONS

This study found that the risks of all cause, cardiovascular, and respiratory mortality increased for up to 60 days after exposure to flood and the associations could vary by local climate type, socioeconomic status, and older age.

Health Effects of Cyclones: A Systematic Review and Meta-Analysis of Epidemiological Studies

BACKGROUND

More intense cyclones are expected in the future as a result of climate change. A comprehensive review is urgently needed to summarize and update the evidence on the health effects of cyclones.

OBJECTIVES

We aimed to provide a systematic review with meta-analysis of current evidence on the risks of all reported health outcomes related to cyclones and to identify research gaps and make recommendations for further research.

METHODS

We systematically searched five electronic databases (MEDLINE, Embase, PubMed, Scopus, and Web of Science) for relevant studies in English published before 21 December 2022. Following the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines, we developed inclusion criteria, screened the literature, and included epidemiological studies with a quantitative risk assessment of any mortality or morbidity-related outcomes associated with cyclone exposures. We extracted key data and assessed study quality for these studies and applied meta-analyses to quantify the overall effect estimate and the heterogeneity of comparable studies.

RESULTS

In total, 71 studies from eight countries (the United States, China, India, Japan, the Philippines, South Korea, Australia, Brazil), mostly the United States, were included in the review. These studies investigated the all-cause and cause-specific mortality, as well as morbidity related to injury, cardiovascular diseases (CVDs), respiratory diseases, infectious diseases, mental disorders, adverse birth outcomes, cancer, diabetes, and other outcomes (e.g., suicide rates, gender-based violence). Studies mostly included only one high-amplitude cyclone (cyclones with a Saffir-Simpson category of 4 or 5, i.e., Hurricanes Katrina or Sandy) and focused on mental disorders morbidity and all-cause mortality and hospitalizations. Consistently elevated risks of overall mental health morbidity, post-traumatic stress disorder (PTSD), as well as all-cause mortality or hospitalizations, were found to be associated with cyclones. However, the results for other outcomes were generally mixed or limited. A statistically significant overall relative risk of 1.09 [95% confidence interval (CI): 1.04, 1.13], 1.18 (95% CI: 1.12, 1.25), 1.15 (95% CI: 1.13, 1.18), 1.26 (95% CI: 1.05, 1.50) was observed for all-cause mortality, all-cause hospitalizations, respiratory disease, and chronic obstructive pulmonary disease hospitalizations, respectively, after cyclone exposures, whereas no statistically significant risks were identified for diabetes mortality, heart disease mortality, and preterm birth. High between-study heterogeneity was observed.

CONCLUSIONS

There is generally consistent evidence supporting the notion that high-amplitude cyclones could significantly increase risks of mental disorders, especially for PTSD, as well as mortality and hospitalizations, but the evidence for other health outcomes, such as chronic diseases (e.g., CVDs, cancer, diabetes), and adverse birth outcomes remains limited or inconsistent. More studies with rigorous exposure assessment, of larger spatial and temporal scales, and using advanced modeling strategy are warranted in the future, especially for those small cyclone-prone countries or regions with low and middle incomes. https://doi.org/10.1289/EHP12158.

Impacts of Hurricane Matthew Exposure on Infections and Antimicrobial Prescribing in North Carolina Veterans

The impact of hurricane-related flooding on infectious diseases in the US is not well understood. Using geocoded electronic health records for 62,762 veterans living in North Carolina counties impacted by Hurricane Matthew coupled with flood maps, we explore the impact of hurricane and flood exposure on infectious outcomes in outpatient settings and emergency departments as well as antimicrobial prescribing. Declines in outpatient visits and antimicrobial prescribing are observed in weeks 0-2 following the hurricane as compared with the baseline period and the year prior, while increases in antimicrobial prescribing are observed 3+ weeks following the hurricane. Taken together, hurricane and flood exposure appear to have had minor impacts on infectious outcomes in North Carolina veterans, not resulting in large increases in infections or antimicrobial prescribing.

Exposure to industrial hog and poultry operations and urinary tract infections in North Carolina, USA

An increasing share of urinary tract infections (UTIs) are caused by extraintestinal pathogenic Escherichia coli (ExPEC) lineages that have also been identified in poultry and hogs with high genetic similarity to human clinical isolates. We investigated industrial food animal production as a source of uropathogen transmission by examining relationships of hog and poultry density with emergency department (ED) visits for UTIs in North Carolina (NC). ED visits for UTI in 2016-2019 were identified by ICD-10 code from NC's ZIP code-level syndromic surveillance system and livestock counts were obtained from permit data and aerial imagery. We calculated separate hog and poultry spatial densities (animals/km²) by Census block with a 5 km buffer on the block perimeter and weighted by block population to estimate mean ZIP code densities. Associations between livestock density and UTI incidence were estimated using a reparameterized Besag-York-Mollié (BYM2) model with ZIP code population offsets to account for spatial autocorrelation. We excluded metropolitan and offshore ZIP codes and assessed effect measure modification by calendar year, ZIP code rurality, and patient sex, age, race/ethnicity, and health insurance status. In single-animal models, hog exposure was associated with increased UTI incidence (rate ratio [RR]: 1.21, 95 % CI: 1.07-1.37 in the highest hog-density tertile), but poultry exposure was associated with reduced UTI rates (RR: 0.86, 95 % CI: 0.81-0.91). However, the reference group for single-animal poultry models included ZIP codes with only hogs, which had some of the highest UTI rates; when compared with ZIP codes without any hogs or poultry, there was no association between poultry exposure and UTI incidence. Hog exposure was associated with increased UTI incidence in areas that also had medium to high poultry density, but not in areas with low poultry density, suggesting that intense hog production may contribute to increased UTI incidence in neighboring communities.

The independent and synergistic impacts of power outages and floods on hospital admissions for multiple diseases

Highly destructive disasters such as floods and power outages (PO) are becoming more commonplace in the U.S. Few studies examine the effects of floods and PO on health, and no studies examine the synergistic effects of PO and floods, which are increasingly co-occurring events. We examined the independent and synergistic impacts of PO and floods on cardiovascular diseases, chronic respiratory diseases, respiratory infections, and food-/water-borne diseases (FWBD) in New York State (NYS) from 2002 to 2018. We obtained hospitalization data from the NYS discharge database, PO data from the NYS Department of Public Service, and floods events from NOAA. Distributed lag nonlinear models were used to evaluate the PO/floods-health association while controlling for time-varying confounders. We identified significant increased health risks associated with both the independent effects from PO and floods, and their synergistic effects. Generally, the Rate Ratios (RRs) for the co-occurrence of PO and floods were the highest, followed by PO alone, and then floods alone, especially when PO coverage is >75th percentile of its distribution (1.72% PO coverage). For PO and floods combined, immediate effects (lag 0) were observed for chronic respiratory diseases (RR:1.58, 95%CI: 1.24, 2.00) and FWBD (RR:3.02, 95%CI: 1.60, 5.69), but delayed effects were found for cardiovascular diseases (lag 3, RR:1.13, 95%CI: 1.03, 1.24) and respiratory infections (lag 6, RR:1.85, 95%CI: 1.35, 2.53). The risk association was slightly stronger among females, whites, older adults, and uninsured people but not statistically significant. Improving power system resiliency could be a very effective way to alleviate the burden on hospitals during co-occurring floods. We conclude that PO and floods have independently and jointly led to increased hospitalization for multiple diseases, and more research is needed to confirm our findings.

Racial Disparities in Climate Change-Related Health Effects in the United States

PURPOSE OF REVIEW

Climate change is causing warming over most parts of the USA and more extreme weather events. The health impacts of these changes are not experienced equally. We synthesize the recent evidence that climatic changes linked to global warming are having a disparate impact on the health of people of color, including children.

RECENT FINDINGS

Multiple studies of heat, extreme cold, hurricanes, flooding, and wildfires find evidence that people of color, including Black, Latinx, Native American, Pacific Islander, and Asian communities are at higher risk of climate-related health impacts than Whites, although this is not always the case. Studies of adults have found evidence of racial disparities related to climatic changes with respect to mortality, respiratory and cardiovascular disease, mental health, and heat-related illness. Children are particularly vulnerable to the health impacts of climate change, and infants and children of color have experienced adverse perinatal outcomes, occupational heat stress, and increases in emergency department visits associated with extreme weather. The evidence strongly suggests climate change is an environmental injustice that is likely to exacerbate existing racial disparities across a broad range of health outcomes.