Relationship between socioeconomic status and gastrointestinal infections in developed countries: A systematic review and meta-analysis

Overadjustment bias in systematic reviews and meta-analyses of socio-economic inequalities in health: a meta-research scoping review

BACKGROUND

Overadjustment bias occurs when researchers adjust for an explanatory variable on the causal pathway from exposure to outcome, which leads to biased estimates of the causal effect of the exposure. This meta-research review aimed to examine how previous systematic reviews and meta-analyses of socio-economic inequalities in health have managed overadjustment bias.

METHODS

We searched Medline and Embase until 16 April 2021 for systematic reviews and meta-analyses of observational studies on associations between individual-level socio-economic position and health outcomes in any population. A set of criteria were developed to examine methodological approaches to overadjustment bias adopted by included reviews (rated Yes/No/Somewhat/Unclear).

RESULTS

Eighty-four reviews were eligible (47 systematic reviews, 37 meta-analyses). Regarding approaches to overadjustment, whereas 73% of the 84 reviews were rated as Yes for clearly defining exposures and outcomes, all other approaches were rated as Yes for <55% of reviews; for instance, 5% clearly defined confounders and mediators, 2% constructed causal diagrams and 35% reported adjusted variables for included studies. Whereas only 2% included overadjustment in risk of bias assessment, 54% included confounding. Of the 37 meta-analyses, 16% conducted sensitivity analyses related to overadjustment.

CONCLUSIONS

Our findings suggest that overadjustment bias has received insufficient consideration in systematic reviews and meta-analyses of socio-economic inequalities in health. This is a critical issue given that overadjustment bias is likely to result in biased estimates of health inequalities and accurate estimates are needed to inform public health interventions. There is a need to highlight overadjustment bias in review guidelines.

Comparison of statistical approaches to predicting norovirus laboratory reports before and during COVID-19: insights to inform public health surveillance

Social distancing interrupted transmission patterns of contact-driven infectious agents such as norovirus during the Covid-19 pandemic. Since routine surveillance of norovirus was additionally disrupted during the pandemic, traditional naïve forecasts that rely only on past public health surveillance data may not reliably represent norovirus activity. This study investigates the use of statistical modelling to predict the number of norovirus laboratory reports in England 4-weeks ahead of time before and during Covid-19 pandemic thus providing insights to inform existing practices in norovirus surveillance in England. We compare the predictive performance from three forecasting approaches that assume different underlying structure of the norovirus data and utilized various external data sources including mobility, air temperature and relative internet searches (Time Series and Regularized Generalized Linear Model, and Quantile Regression Forest). The performance of each approach was evaluated using multiple metrics, including a relative prediction error against the traditional naive forecast of a five-season mean. Our data suggest that all three forecasting approaches improve predictive performance over the naïve forecasts, especially in the 2020/21 season (30-45% relative improvement) when the number of norovirus reports reduced. The improvement ranged from 7 to 22% before the pandemic. However, performance varied: regularized regression incorporating internet searches showed the best forecasting score pre-pandemic and the time series approach achieved the best results post pandemic onset without external data. Overall, our results demonstrate that there is a significant value for public health in considering the adoption of more sophisticated forecasting tools, moving beyond traditional naïve methods, and utilizing available software to enhance the precision and timeliness of norovirus surveillance in England.

Healthcare Disparities Among Homeless Patients Hospitalized With Gastrointestinal Bleeding: A Propensity-Matched, State-Level Analysis

GOALS

Examine outcomes among homeless patients admitted with gastrointestinal (GI) bleeding, including all-cause mortality and endoscopic intervention rates.

BACKGROUND

Hospitalizations among homeless individuals have increased steadily since at least 2007 but little is known about GI outcomes in these patients.

STUDY

The 2010-2014 Healthcare Utilization Project (HCUP) State Inpatient Databases from New York and Florida were used to identify adults admitted with a primary diagnosis of acute upper or lower GI bleed. Homeless patients were 1:3 matched with nonhomeless patients using a propensity-score greedy-matched algorithm. The primary outcome (all-cause in-hospital mortality) and secondary outcomes (30-day readmission rates, endoscopy utilization, length of stay, and total hospitalization costs) were compared.

RESULTS

We matched 4074 homeless patients with 12,222 nonhomeless patients. Most hospitalizations for homeless individuals were concentrated in 113 (26.4%) of 428 hospitals. Homeless adults were more likely to be younger, male, African American or Hispanic, and on Medicaid. They experienced significantly higher odds of all-cause inpatient mortality compared with nonhomeless patients admitted with GI bleeding (OR 1.37, 95% CI 1.11-1.69). Endoscopy utilization rates were also lower for both upper (OR 0.62, 95% CI 0.55-0.71) and lower (OR 0.76, 95% CI 0.68-0.85) GI bleeding, though upper endoscopy rates within the first 24 hours were comparable (OR 1.11, 95% CI 1.00-1.23). Total hospitalization costs were lower ($9,715 vs. $12,173, P <0.001) while 30-day all-cause readmission rates were significantly higher in the homeless group (14.9% vs. 18.4%, P <0.001).

CONCLUSIONS

Homeless patients hospitalized for GI bleeding face disparities, including higher mortality rates and lower endoscopy utilization.

A novel approach in public health surveillance: searching the illegal dairy trade in Facebook

This paper uses the internet-based biosurveillance to describe the Brazilian e-commerce of non-inspected dairy products and maps its traditional sale in a medium-sized city (Londrina). We searched the sales of illegal dairy products on Facebook Marketplace and conducted a census of street markets and a random sample of formal markets. Although prohibited in Brazil, consumers can easily find informal dairy products on internet and retail sale. In addition, 7% of the food products hold a false label to mimic food inspection. The e-commerce was linked with regions with higher access to technology and Human Development Index (HDI). We believe that our approach shows a step forward in the public health interventions and could be replicated stimulating debates about policies required to improve the public health surveillance.

Health inequalities in infectious diseases: a systematic overview of reviews

OBJECTIVES

The aim of this systematic overview of reviews was to synthesise available evidence on inequalities in infectious disease based on three dimensions of inequalities; inclusion health groups, protected characteristics and socioeconomic inequalities.

METHODS

We searched MEDLINE, Embase, Web of Science and OpenGrey databases in November 2021. We included reviews published from the year 2000 which examined inequalities in the incidence, prevalence or consequences of infectious diseases based on the dimensions of interest. Our search focused on tuberculosis, HIV, sexually transmitted infections, hepatitis C, vaccination and antimicrobial resistance. However, we also included eligible reviews of any other infectious diseases. We appraised the quality of reviews using the Assessment of Multiple Systematic Reviews V.2 (AMSTAR2) checklist. We conducted a narrative data synthesis.

RESULTS

We included 108 reviews in our synthesis covering all the dimensions of inequalities for most of the infectious disease topics of interest, however the quality and volume of review evidence and consistency of their findings varied. The existing literature reviews provide strong evidence that people in inclusion health groups and lower socioeconomic status are consistently at higher risk of infectious diseases, antimicrobial resistance and incomplete/delayed vaccination. In the protected characteristics dimension, ethnicity, and sexual orientation are important factors contributing to inequalities across the various infectious disease topics included in this overview of reviews.

CONCLUSION

We identified many reviews that provide evidence of various types of health inequalities in different infectious diseases, vaccination, and antimicrobial resistance. We also highlight areas where reviews may be lacking. The commonalities in the associations and their directions suggest it might be worth targeting interventions for some high risk-groups that may have benefits across multiple infectious disease outcomes rather than operating purely in infectious disease siloes.

An allergist's approach to food poisoning

Foodborne illnesses represent a significant global health concern. These preventable diseases lead to substantial mortality and morbidity worldwide. Substantial overlap with food allergy exists with similar clinical presentations and symptom onset. Knowledge of the typically implicated microorganisms and toxins can help properly identify these diseases. A thorough history is essential to differentiate between these 2 disorders. The types of food implicated may be similar including milk, egg, fish, and shellfish. The timing of symptom onset may overlap and lead to misdiagnosis of disorders such as food protein-induced enterocolitis syndrome. Classically, histamine-related food poisoning is also typically confused with true food allergy and may be seen as related to fish and cheese. Knowledge of epidemiology, patterns, and etiology of allergic conditions and foodborne illness may help the allergist differentiate among these common diseases.

Worker Protection Scenarios for General Analytical Testing Facility under Several Infection Propagation Risks: Scoping Review, Epidemiological Model and ISO 31000

Infectious disease is a risk threating industrial operations and worker health. In gastrointestinal disease cases, outbreak is sporadic, and propagation is often terminated within certain populations, although cases in industrial sites are continuously reported. The ISO 31000 international standard for risk management, an epidemiological triad model, and a scoping review were the methods used to establish response procedures (scenarios) to protect workers from the risk of the propagation of a gastrointestinal disease. First, human reservoirs and transmission routes were identified as controllable risk sources based on a scoping review and the use of a triad model. Second, the possibility of fomite- or surface-mediated transmission appeared to be higher based on environmental characterization. Thus, the propagation could be suppressed using epidemiological measures categorized by reservoirs (workers) or transmission routes during a primary case occurrence. Next, using results of a matrix, a strengths-weaknesses-opportunities-threats analysis and a scoping review, the risk treatment option was determined as risk taking and sharing. According to epidemiology of gastrointestinal infections, systematic scenarios may ensure the efficacy of propagation control. Standardized procedures with practicality and applicability were established for categorized scenarios. This study converged ISO 31000 standards, an epidemiological model, and scoping review methods to construct a risk management scenario (non-pharmaceutical intervention) optimized for the unique characteristics of a specific occupational cluster.

Early life adversity, inflammation, and immune function: An initial test of adaptive response models of immunological programming

Much research indicates that exposure to early life adversity (ELA) predicts chronic inflammatory activity, increasing one's risk of developing diseases of aging later in life. Despite its costs, researchers have proposed that chronic inflammation may be favored in this context because it would help promote immunological vigilance in environments with an elevated risk of infection and injury. Although intuitively appealing, the assumption that exaggerated inflammatory activity predicts favorable immunological outcomes among those exposed to ELA has not been tested. Here, we seek to address this gap, examining the links between exposure to ELA, inflammation, and immune function. Consistent with others' work, results revealed that those from low socioeconomic status (SES) childhood environments exhibited exaggerated unstimulated inflammatory activity relative to what was observed among those from higher SES childhood environments. Further, results revealed that - although levels of inflammation predicted the magnitude of immunological responses in those from higher SES backgrounds - for those who grew up in low SES environments, higher levels of inflammation were unrelated to the magnitude of immunological responses. Results suggest that exaggerated inflammatory activity in the context of ELA may not predict improved ability to manage acute immunological threats.

Lack of Association of Household Income and Acute Gastroenteritis Disease Severity in Young Children: A Cohort Study

OBJECTIVE

To determine if low household income is associated with disease severity following emergency department (ED) discharge in children with acute gastroenteritis (AGE).

METHODS

We conducted a secondary analysis employing data collected in 10 US-based tertiary-care, pediatric EDs between 2014 and 2017. Participants were aged 3 to 48 months and presented for care due to AGE. Income status was defined based on 1) home ZIP Code median annual home income and 2) percentage of home ZIP Code households below the poverty threshold. The primary outcome was moderate-to-severe AGE, defined by a post-ED visit Modified Vesikari Scale (MVS) score ≥9. Secondary outcomes included in-person revisits, revisits with intravenous rehydration, hospitalization, and etiologic pathogens.

RESULTS

About 943 (97%) participants with a median age of 17 months (interquartile range 10, 28) completed follow-up. Post-ED visit MVS scores were lower for the lowest household income group (adjusted: -0.60; 95% confidence interval [CI]: -1.13, -0.07). Odds of experiencing an MVS score ≥9 did not differ between groups (adjusted odds ratio: 0.91; 95% CI: 0.54, 1.52). No difference in the post-ED visit MVS score or the proportion of participants with scores ≥9 was observed using the national poverty threshold definition. For both income definitions, there were no differences in terms of revisits following discharge, hospitalizations, and intravenous rehydration. Bacterial enteropathogens were more commonly identified in the lowest socioeconomic group using both definitions.

CONCLUSIONS

Lower household income was not associated with increased disease severity or resource use. Economic disparities do not appear to result in differences in the disease course of children with AGE seeking ED care.

Linking pathogens, people and places: Using geo-ethnography to understand place-based, socio-economic inequalities in gastrointestinal infections in the UK

This ethnographic study in two socio-economically contrasting areas employed geo-ethnography, underpinned by a relational approach, to understand inequalities in gastrointestinal infections in families with young children. In our 'relatively disadvantaged' area, gastrointestinal infections spread to multiple households within a small radius, whereas in our 'relatively advantaged' area, illness was confined to one household or dispersed long distances. These differences were shaped by historical, social and economic contrasts in: housing; social networks and childcare arrangements; employment and household income. Our findings show how linking places, pathogens and people helps us understand inequalities in gastrointestinal infections and may be pertinent to other infectious diseases such as COVID-19.

All-cause gastroenteritis hospitalisations of children decreased after the introduction of rotavirus vaccine in Stockholm

BACKGROUND

In Stockholm, Sweden, rotavirus vaccination was offered to children born after 1 March 2014. Our aim was to describe rates of hospitalisation due to community-acquired gastroenteritis before and after the introduction of the vaccine, and aetiology, underlying medical conditions and complications in admitted children.

METHODS

We retrospectively included patients from our catchment area hospitalised with a diagnosis of gastroenteritis during ten infection seasons 2008/2009-2017/2018, whereof six seasons prevaccination and four seasons postvaccination. We studied virus detection data and the patients' medical records.

RESULTS

We included 3718 episodes in 3513 children. In 2967 (80%), stools were tested with virus isolation, ELISA, PCR, or bacterial culture; 479 (16%) tested negative. The incidence rates, with 95% confidence intervals, for children <5 years hospitalised for rotavirus gastroenteritis were 2.9 (2.8-3.1) per 1000 person-years prevaccination and 0.65 (0.56-0.74) postvaccination, for a rate ratio (RR) of 0.22 (0.19-0.26, p < .001). The rates for all-cause gastroenteritis were 5.6 (5.4-5.9) prevaccination and 2.5 (2.3-2.7) postvaccination, RR 0.45 (0.42-0.50, p < .001). In 5-17-year-old children norovirus dominated with little change over time. Of patients <5 years, those with underlying conditions constituted a larger proportion postvaccination than prevaccination (30.7% vs. 24.2%, p < .001). A complication other than dehydration, most commonly seizures, arose in 8.8% of the patients <5 years prevaccination and 11.4% postvaccination (p < .05).

CONCLUSIONS

Rotavirus vaccination reduced the number of children <5 years requiring hospital care for gastroenteritis. We saw no replacement of rotavirus by other viruses.

How are inequalities generated in the management and consequences of gastrointestinal infections in the UK? An ethnographic study

Gastrointestinal infections are an important global public health issue. In the UK, one in four people experience a gastrointestinal infection each year and epidemiological research highlights inequalities in the burden of disease. Specifically, poorer children are at greater risk of infection and the consequences of illness, such as symptom severity and time off work/school, are greater for less privileged groups of all ages. Gastrointestinal infections are, however, largely ‘hidden’ within the home and little is known about the lived experience and practices surrounding these illnesses, how they vary across contrasting socioeconomic contexts, or how inequalities in the disease burden across socioeconomic groups might come about. This paper presents data from an ethnographic study which illuminate how socioeconomic inequalities in the physical and material management and consequences of gastrointestinal infections are generated in families with young children. The study shows how the ‘work’ needed to manage gastrointestinal infections is more laborious for people living in more ‘disadvantaged’ conditions, exacerbated by: more overcrowded homes with fewer washing and toilet facilities; inflexible employment; low household incomes; and higher likelihood of co-morbidities which can be made worse by having a gastrointestinal infection. Our findings call into question the current approach to prevention of gastrointestinal infections which tend to focus almost exclusively on individual behaviours, which are not adapted to reflect differences in socioeconomic context. Public health agencies should also consider how wider social, economic and policy contexts shape inequalities in the management and consequences of illness. Our findings are also pertinent to the COVID-19 pandemic response in the UK. They highlight how research and policy approaches to acute infectious diseases need to take into consideration the differing lived experiences of contrasting households if they wish to address (and avoid exacerbating) inequalities in the future.

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First ethnographic study to examine UK socioeconomic inequalities in GI infections.

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GI infections create a huge amount of labour for all families with young children.

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Co-morbidities, poorer living conditions and low income increase GI infection labour.

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Low paid, insecure, inflexible work exacerbates material consequences of infection.

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GI infection policy should look beyond behavioural advice to address inequalities.

Sociodemographic Inequalities in Urinary Tract Infection in 2 Large California Health Systems

Background

Urinary tract infection (UTI) accounts for a substantial portion of outpatient visits and antibiotic prescriptions in the United States. Few studies have considered sociodemographic factors including low socioeconomic status (SES)—which may increase residential crowding, inappropriate antibiotic prescribing, or comorbidities—as UTI or multidrug-resistant (MDR) UTI risk factors.

Methods

We used 2015–2017 electronic health record data from 2 California health care systems to assess whether 3 sociodemographic factors—use of Medicaid, use of an interpreter, and census tract–level deprivation—were associated with overall UTI or MDR UTI. UTIs resistant to ≥3 antibiotic classes were considered MDR.

Results

Analyses included 601 352 UTI cases, 1 303 455 controls, and 424 977 urinary Escherichia coli isolates from Kaiser Permanente Southern California (KPSC) and Sutter Health in Northern California. The MDR prevalence was 10.4% at KPSC and 12.8% at Sutter Health. All 3 sociodemographic factors (ie, use of Medicaid, using an interpreter, and community deprivation) were associated increased risk of MDR UTI. For example, using an interpreter was associated with a 36% (relative risk [RR], 1.36; 95% CI, 1.31 to 1.40) and 28% (RR, 1.28; 95% CI, 1.22 to 1.34) increased risk of MDR UTI at KPSC and Sutter Health, respectively, adjusted for SES and other potential confounding variables. The 3 sociodemographic factors were only weakly associated with UTI overall.

Conclusions

We found low SES and use of an interpreter to be novel risk factors for MDR UTI in the United States.

Disgusting disruptions: Capturing the everyday experience and burden of managing gastrointestinal infections in the home

Gastrointestinal (GI) infections exert a significant public health burden in the United Kingdom and the numbers of episodes are increasing. Younger children are considered particularly vulnerable to infection, and can experience 2-3 GI infections episodes per year, with consequences being more severe for more disadvantaged children, who are much more likely to be admitted to hospital. Few qualitative studies have explored the lived experience of GI infection in the community in the UK. The aim of the study reported here was to contribute to addressing this evidence gap, by examining the consequences of GI infection for 'normal' family life. Eighteen mothers with young children who had recently experienced a gastrointestinal infection were recruited from two socioeconomically contrasting neighbourhoods in North West of England. The findings demonstrated that GI infections were particularly disruptive: experienced as disgusting, laborious and stressful and significantly impacted normal family routines. Women felt burdened by the heavy physical and emotional demands of caring for a GI infection, resulting in feelings of isolation and insufficient support in their caring role from male partners. Tensions also arose from interactions with external community organisations, particularly in complying with their regulations on infection which often undermined caregivers knowledge and expertise of what was best for their children. This study challenges assumptions that managing GI infections in the home is unproblematic and experienced by caregivers as a 'minor ailment.' Infection control measures need to incorporate insights gleaned from the day-to-day realities of caring for sick children in the community.

Neighbourhood unemployment and other socio-demographic predictors of emergency hospitalisation for infectious intestinal disease in England: A longitudinal ecological study

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We examined trends in infectious intestinal disease (IID) hospitalisations in England.

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Overall IID admission rates for children and older adults declined between 2012 & 2017.

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Increasing unemployment was associated with increasing IID admission rates.

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Healthcare access, underlying morbidity and ethnicity were also associated with IID rates.

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Policies should address inequalities in emergency IID hospitalisations.

Background

Previous studies have observed that infectious intestinal disease (IID) related hospital admissions are higher in more deprived neighbourhoods. These studies have mainly focused on paediatric populations and are cross-sectional in nature. This study examines recent trends in emergency IID admission rates, and uses longitudinal methods to investigate the effects of unemployment (as a time varying measure of neighbourhood deprivation) and other socio-demographic characteristics on IID admissions for adults and children in England.

Methods

A longitudinal ecological analysis was performed using Hospital Episode Statistics on emergency hospitalisations for IID, collected over the time period 2012–17 across England. Analysis was conducted at the neighbourhood (Lower-layer Super Output Area) level for three age groups (0–14; 15–64; 65+ years). Mixed-effect Poisson regression models were used to assess the relationship between trends in neighbourhood unemployment and emergency IID admission rates, whilst controlling for measures of primary and secondary care access, underlying morbidity and the ethnic composition of each neighbourhood.

Results

From 2012–17, declining trends in emergency IID admission rates were observed for children and older adults overall, while rates increased for some sub-groups in the population. Each 1 percentage point increase in unemployment was associated with a 6.3, 2.4 and 4% increase in the rate of IID admissions per year for children [IRR=1.06, 95%CI 1.06–1.07], adults [IRR=1.02, 95%CI 1.02–1.03] and older adults [IRR=1.04, 95%CI 1.036–1.043], respectively. Increases in poor primary care access, the percentage of people from a Pakistani ethnic background, and the prevalence of long-term health problems, in a neighbourhood, were also associated with increases in IID admission rates.

Conclusions

Increasing trends in neighbourhood deprivation, as measured by unemployment, were associated with increases in emergency IID admission rates for children and adults in England, despite controlling for measures of healthcare access, underlying morbidity and ethnicity. Research is needed to improve understanding of the mechanisms that explain these inequalities, so that effective policies can be developed to reduce the higher emergency IID admission rates experienced by more disadvantaged communities.

Influence of socio-economic status on Shiga toxin-producing Escherichia coli (STEC) infection incidence, risk factors and clinical features

Shiga toxin-producing Escherichia coli (STEC) infection can cause serious illness including haemolytic uraemic syndrome. The role of socio-economic status (SES) in differential clinical presentation and exposure to potential risk factors amongst STEC cases has not previously been reported in England. We conducted an observational study using a dataset of all STEC cases identified in England, 2010–2015. Odds ratios for clinical characteristics of cases and foodborne, waterborne and environmental risk factors were estimated using logistic regression, stratified by SES, adjusting for baseline demographic factors. Incidence was higher in the highest SES group compared to the lowest (RR 1.54, 95% CI 1.19–2.00). Odds of Accident and Emergency attendance (OR 1.35, 95% CI 1.10–1.75) and hospitalisation (OR 1.71, 95% CI 1.36–2.15) because of illness were higher in the most disadvantaged compared to the least, suggesting potential lower ascertainment of milder cases or delayed care-seeking behaviour in disadvantaged groups. Advantaged individuals were significantly more likely to report salad/fruit/vegetable/herb consumption (OR 1.59, 95% CI 1.16–2.17), non-UK or UK travel (OR 1.76, 95% CI 1.40–2.27; OR 1.85, 95% CI 1.35–2.56) and environmental exposures (walking in a paddock, OR 1.82, 95% CI 1.22–2.70; soil contact, OR 1.52, 95% CI 2.13–1.09) suggesting other unmeasured risks, such as person-to-person transmission, could be more important in the most disadvantaged group.

Impact of vaccination on the risk factors for acute rotavirus diarrhea: An analysis of the data of a cluster randomized trial conducted in a rural area of Bangladesh

BACKGROUND

Rotavirus is one of the causes of severe diarrhea and death in young children. To control the disease, safe and effective vaccines are being used in several countries. We assessed the impact of vaccination on the risk factors for acute rotavirus diarrhea (ARD) in Bangladesh.

METHODS

We used the data of a cluster-randomized trial. The clusters were 142 villages, 71 in each of the two arms of study. The infants were offered human rotavirus vaccine (HRV), Rotarix, over three-year period. We divided the time period into two equal periods (T1 and T2). A generalized estimating equation with logit-link function was used to evaluate the risk factors by arm and by period.

RESULTS

Among 10,917 children, 5,759 (53%) were in the HRV villages. We had 359 cases; 44% in the HRV villages. Mean age of attack was similar between the arms of study in T1, but significantly higher in HRV villages than that in the non-HRV villages in T2. In HRV villages, males were at a higher risk of having ARD than females in T1, but not in T2. In contrast, males were at a higher risk of having ARD in both the time periods in non-HRV villages. In HRV-villages, children having literate mother were at significantly higher risk of having ARD in T1 but not in T2; whereas children in the non-HRV villages had a higher risk of having ARD in T2. Children living in an area with higher phone users had more cases than their counterpart in non-HRV villages, but not in HRV villages.

CONCLUSION

Our study illustrates that several risk factors for ARD varied between the two arms of study as well as between the two periods of study. Assessing post-vaccination risk factors is, therefore, important for understanding the impact of vaccination and undertaking post-vaccination control measures.

What is the qualitative evidence concerning the risks, diagnosis, management and consequences of gastrointestinal infections in the community in the United Kingdom? A systematic review and meta-ethnography

BACKGROUND

Gastrointestinal (GI) infections cause a significant public health burden worldwide and in the UK with evidence pointing to socio-economic inequalities, particularly among children. Qualitative studies can help us understand why inequalities occur and contribute to developing more effective interventions. This study had two aims: 1. Conduct a systematic review to determine the extent and nature of UK qualitative evidence on gastrointestinal infections; 2. Use meta-ethnography to examine the influences of the differing social contexts in which people live.

METHODS

MEDLINE, Scopus, Web of science, CINAHL and JSTOR were searched for UK qualitative studies engaging with the risk, diagnosis, management or consequences of gastrointestinal infections from 1980 to July 2019. Five reviewers were involved in applying inclusion and exclusion criteria, extracting and synthesising data (PROSPERO CRD 42017055157).

RESULTS

Searches identified 4080 studies, 18 met the inclusion criteria. The majority (n = 16) contained data relating to the risk of gastrointestinal infection and these made up the main synthesis. The tenets of meta-ethnography were used to glean new understandings of the role of social and environmental contexts in shaping the risk of gastrointestinal infection, specifically with respect to foodborne GI illness. Three main explanations concerning risk emerged from the data: explanations of risk in the community were underpinned by understandings of 'bugs', dirt and where food comes from; risks were negotiated in households alongside diverse processes of decision making around food; and resources available to households shaped food practices.

CONCLUSION

This systematic review highlights the scarcity of UK qualitative evidence examining gastrointestinal infections. Apart from risk, questions around diagnosis, management and consequences of illness were largely untouched. No studies investigated patterning by socio-economic status. Nevertheless, the meta-ethnography yielded wider contextual theories and explanations as to why people might not follow food hygiene guidance, giving pointers to the types of qualitative enquiry needed to develop more effective interventions.

Antibiotic Resistance in Staphylococcus aureus from Poultry and Poultry Products in uMgungundlovu District, South Africa, Using the "Farm to Fork" Approach

Background: This study determined the prevalence and antibiotic susceptibility profiles of Staphylococcus aureus isolated from selected critical control points (farm, transport, abattoir, and retail product) in an intensive poultry production system in the uMgungundlovu District, South Africa, using the "farm to fork" approach. Materials and Methods: Three hundred eighty-four samples from poultry and poultry products were examined across the "farm to fork" continuum for S. aureus using selective media, biochemical tests, and API Staph kit and confirmed by polymerase chain reaction identification of the nuc gene. Antibiotic susceptibility testing of the isolates was determined by the Kirby-Bauer disc diffusion method to 19 antimicrobials and to vancomycin by the broth microdilution technique. Results: The overall prevalence rate of S. aureus was 31.25% (n = 120/384), distributed across the continuum: farm site (40), transport (15), abattoir (30), and retail point (35). The isolates were resistant to tetracycline (61.67%), penicillin G (55.83%), erythromycin (54.17%), clindamycin (43.33%), doxycycline (36.67%), ampicillin (34.17%), moxifloxacin (30.83%), amikacin (30.83%), trimethoprim-sulfamethoxazole (30.00%), and levofloxacin (23.33%). A 100% susceptibility to tigecycline, teicoplanin, vancomycin, nitrofurantoin, chloramphenicol, and linezolid was observed in all isolates. The rate of multidrug resistance and the multiple antibiotic resistance index of the strains were 39.17% and 0.23%, respectively. The isolates showed similar patterns of resistance to commonly used growth promoters and antibiotics in veterinary and human medicine belonging to the same class. Conclusion: It is evident that the different antibiotics and growth promoters used in poultry production are exerting selection pressure for the emergence and co-selection of antibiotic-resistant bacteria in the production system, necessitating efficient antibiotic stewardship guidelines to streamline their use.

Family income and exposure to norovirus in childhood: Findings from the UK Millennium Cohort Study

Children from low income families are at greater risk of poorer health outcomes than their wealthier peers. Hospital admissions for children with gastroenteritis increase as deprivation increases. Noroviruses are responsible for 47-96% of outbreaks of acute paediatric gastroenteritis, and 5-36% of sporadic cases worldwide. However, evidence on the relationship between family income and childhood exposure to norovirus is still limited, with published studies pointing to conflicting results. This study explored the relationship between family income and early childhood exposure to norovirus in the United Kingdom using data from the Millennium Cohort Study linked to serological data. Exposure to norovirus was measured by the level of human norovirus-specific antibodies (titres) obtained from oral fluid samples collected from 5962 pre-school age UK children and tested for Norovirus-specific Immunoglobulin G (IgG). Multivariable linear and quantile regression analyses were conducted to investigate the extent to which family income was associated with child norovirus exposure, and to explore the potential mechanisms through which income might translate into norovirus exposure. Higher norovirus-specific IgG titres were associated with higher family income, but the relationship weakened after controlling for potential mediating factors, mainly increased opportunities for person-to-person contacts, such as formal childcare arrangements. This study provides novel evidence that can help inform and prioritise policy interventions (e.g. vaccination) and health promotion programmes to reduce child health inequalities in the area of gastrointestinal infections.

The dietary inflammatory index is associated with gastrointestinal infection symptoms in the national health and nutrition examination survey

Inflammation influences many aspects of health including gastrointestinal illnesses. Associations between the Dietary Inflammatory Index (DII®) and gastrointestinal symptoms were examined using cross-sectional data from the National Health and Nutrition Examination Survey (years 2005-2014, n = 25,553). Outcomes included self-reported presence of mucus or liquid in bowel leakage and stomach illness in the past month, diarrhoea in the past year and number of weekly bowel movements. Energy-adjusted DII (E-DII) scores were estimated from one 24-h dietary recall. Analyses included survey design-appropriate logistic and linear regression. Compared to E-DII quartile 1 (anti-inflammatory), E-DII quartile 4 (pro-inflammatory) had elevated odds of mucus in leakage: 71% (95% confidence interval [95%CI] = 1.01-1.20); liquid in leakage: 74% (95%CI = 1.30-2.33); stomach illness: 43% (95%CI = 1.18-1.72); and diarrhoea: 65% (95%CI = 1.21-2.26). Those with more anti-inflammatory diets had more bowel movements. Future questions should address whether anti-inflammatory diets provide protective effects against gastrointestinal infections and if these relationships are modified by other health behaviours.

The Effect of Rotavirus Vaccine on Socioeconomic Differentials of Paediatric Care Due to Gastroenteritis in Swedish Infants

Background: Previous Swedish studies have shown a social gradient on paediatric care for viral gastroenteritis. Aim: To study the effect of a free rotavirus vaccine programme on hospital care for viral gastroenteritis. Method: A register-based national cohort study of paediatric in- and outpatient care for viral gastroenteritis in children <2 years old in two Swedish counties in 2014–2017, with the rest of the country as comparison. Adjusted hazard ratios were estimated by the differences-in-differences (DiD) estimator in Cox regression in the entire cohort and by social indicators. Results: Reductions of 37% and 24% for inpatient care, and 11 % and 21% for outpatient care for viral gastroenteritis were found in the Stockholm and Jönköping counties, respectively, after adjusting for time trends and social indicators. For inpatient care, the change was similar over social groups in both counties. In the larger county of Stockholm, smaller reductions in outpatient care were detected for children in socially disadvantaged families. Conclusions: A free rotavirus vaccination programme moderately reduced paediatric care for viral gastroenteritis. There were indications of an increase in socioeconomic differences in paediatric outpatient care for viral gastroenteritis, but further studies are needed to confirm this result in a broader health care perspective.

Sampling and Sampling Frames in Big Data Epidemiology

Purpose of Review

The 'big data' revolution affords the opportunity to reuse administrative datasets for public health research. While such datasets offer dramatically increased statistical power compared with conventional primary data collection, typically at much lower cost, their use also raises substantial inferential challenges. In particular, it can be difficult to make population inferences because the sampling frames for many administrative datasets are undefined. We reviewed options for accounting for sampling in big data epidemiology.

Recent Findings

We identified three common strategies for accounting for sampling when the data available were not collected from a deliberately constructed sample: 1) explicitly reconstruct the sampling frame, 2) test the potential impacts of sampling using sensitivity analyses, and 3) limit inference to sample.

Summary

Inference from big data can be challenging because the impacts of sampling are unclear. Attention to sampling frames can minimize risks of bias.

Sociodemographic and clinical risk factors for paediatric typical haemolytic uraemic syndrome: retrospective cohort study

OBJECTIVES

Haemolytic uraemic syndrome (HUS) following Shiga toxin-producing Escherichia coli (STEC) infection is the the most common cause of acute renal failure among children in the UK. This study explored differential progression from STEC to HUS by social, demographic and clinical risk factors.

METHODS

We undertook a retrospective cohort study linking two datasets. We extracted data on paediatric STEC and HUS cases identified in the Public Health England National Enhanced Surveillance System for STEC and British Paediatric Surveillance Unit HUS surveillance from 1 October 2011 to 31 October 2014. Using logistic regression, we estimated the odds of HUS progression by risk factors.

RESULTS

1059 paediatric STEC cases were included in the study, of which 207 (19.55%, 95% CI 17% to 22%) developed HUS. In the fully adjusted model, the odds of progression to HUS were highest in those aged 1-4 years (OR 4.93, 95% CI 2.30 to 10.56, compared with 10-15 years), were infected with an Shiga toxin (stx) 2-only strain (OR 5.92, 95% CI 2.49 to 14.10), were prescribed antibiotics (OR 8.46, 95% CI 4.71 to 15.18) and had bloody diarrhoea (OR 3.56, 95% CI 2.04 to 6.24) or vomiting (OR 4.47, 95% CI 2.62 to 7.63), but there was no association with progression to HUS by socioeconomic circumstances or rurality.

CONCLUSION

Combining data from an active clinical surveillance system for HUS with the national enhanced STEC surveillance system suggests that 20% of diagnosed paediatric STEC infections in England resulted in HUS. No relationship was found with socioeconomic status or rurality of cases, but differences were demonstrated by age, stx type and presenting symptoms.