Association between PM10 exposure and risk of myocardial infarction in adults: A systematic review and meta-analysis

BACKGROUND

Air pollution has several negative health effects. Particulate matter (PM) is a pollutant that is often linked to health adversities. PM2.5 (PM with an aerodynamic diameter of ≤2.5μm) exposure has been associated with negative cardiovascular (CV) outcomes. However, the impact of PM10 (PM with an aerodynamic diameter of ≤10μm) exposure is often overlooked due to its limited ability to pass the alveolar barrier. This study aims to assess the association between PM10 exposure and risk of myocardial infarction (MI) amongst adults (≥18 years of age) as this has been poorly studied.

METHODS

The study protocol was published on the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42023409796) on March 31, 2023. Literature searches were conducted on 4 databases (Ovid Medline, Embase, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and Web of Science) on January 17, 2023, for studies looking at associations between PM and MI. English studies from all time periods were assessed. Studies selected for review were time-series, case-crossover, and cohort studies which investigated the risk of MI as an outcome upon PM10 exposure. The quality of evidence was assessed using Cochrane's Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Data for different risk outcomes (risk ratio (RR), odds ratio (OR), hazard ratio (HR)) and 3 lags was meta-analyzed using an inverse variance statistical analysis using a random effects model. The pooled effect sizes and the 95% confidence intervals (CIs) were reported in forest plots.

RESULTS

Among the 1,099 studies identified, 41 were included for review and 23 were deemed eligible for meta-analysis. Our analysis revealed that there is an increased risk (OR = 1.01; 95% CI:1.00-1.02) of MI with a 10 μg/m3 increase in PM10 after a lag 0 and lag 1 delay.

CONCLUSIONS

Our findings indicate that PM10 exposure is associated with an increased risk of MI. This can aid in informing environmental policy-making, personal-level preventative measures, and global public health action.

Effects of ambient air pollution on obesity and ectopic fat deposition: a protocol for a systematic review and meta-analysis

INTRODUCTION

Globally, the prevalence of obesity tripled from 1975 to 2016. There is evidence that air pollution may contribute to the obesity epidemic through an increase in oxidative stress and inflammation of adipose tissue. However, the impact of air pollution on body weight at a population level remains inconclusive. This systematic review and meta-analysis will estimate the association of ambient air pollution with obesity, distribution of ectopic adipose tissue, and the incidence and prevalence of non-alcoholic fatty liver disease among adults.

METHODS AND ANALYSIS

The study will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for conduct and reporting. The search will include the following databases: Ovid Medline, Embase, PubMed, Web of Science and Latin America and the Caribbean Literature on Health Sciences, and will be supplemented by a grey literature search. Each article will be independently screened by two reviewers, and relevant data will be extracted independently and in duplicate. Study-specific estimates of associations and their 95% Confidence Intervals will be pooled using a DerSimonian and Laird random-effects model, implemented using the RevMan software. The I2 statistic will be used to assess interstudy heterogeneity. The confidence in the body of evidence will be assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

ETHICS AND DISSEMINATION

As per institutional policy, ethical approval is not required for secondary data analysis. In addition to being published in a peer-reviewed journal and presented at conferences, the results of the meta-analysis will be shared with key stakeholders, health policymakers and healthcare professionals.

PROSPERO REGISTRATION NUMBER

CRD42023423955.

Burden, determinants, consequences and care of multimorbidity in rural and urbanising Telangana, India: protocol for a mixed-methods study within the APCAPS cohort

INTRODUCTION

The epidemiological and demographic transitions are leading to a rising burden of multimorbidity (co-occurrence of two or more chronic conditions) worldwide. Evidence on the burden, determinants, consequences and care of multimorbidity in rural and urbanising India is limited, partly due to a lack of longitudinal and objectively measured data on chronic health conditions. We will conduct a mixed-methods study nested in the prospective Andhra Pradesh Children and Parents' Study (APCAPS) cohort to develop a data resource for understanding the epidemiology of multimorbidity in rural and urbanising India and developing interventions to improve the prevention and care of multimorbidity.

METHODS AND ANALYSIS

We aim to recruit 2100 APCAPS cohort members aged 45+ who have clinical and lifestyle data collected during a previous cohort follow-up (2010-2012). We will screen for locally prevalent non-communicable, infectious and mental health conditions, alongside cognitive impairments, disabilities and frailty, using a combination of self-reported clinical diagnosis, symptom-based questionnaires, physical examinations and biochemical assays. We will conduct in-depth interviews with people with varying multimorbidity clusters, their informal carers and local healthcare providers. Deidentified data will be made available to external researchers.

ETHICS AND DISSEMINATION

The study has received approval from the ethics committees of the National Institute of Nutrition and Indian Institute of Public Health Hyderabad, India and the London School of Hygiene and Tropical Medicine, UK. Meta-data and data collection instruments will be published on the APCAPS website alongside details of existing APCAPS data and the data access process (www.lshtm.ac.uk/research/centres-projects-groups/apcaps).

Burden of chronic cough on social participation, healthcare resource utilisation and activities of daily living in the Canadian Longitudinal Study on Aging (CLSA)

BACKGROUND

Chronic cough is a common troublesome condition, but it is unclear whether dry or productive chronic cough and sex, impacts the burden of cough differently.

METHODS

The Canadian Longitudinal Study on Aging is a nationally generalizable, stratified random sample of adults aged 45-85 years. Chronic cough was identified based on a self-reported daily cough in the last 12 months assessed at baseline (2011-2015) and follow-up (2015-2018). Odds ratios (95 % CI) for cough status and change in social participation activities (SPA), healthcare resource utilisation (HCRU), basic activities of daily living (ADLs) and instrumental activities of daily living (IADLs) were estimated using a weighted generalised estimating equation (WGEE). Results were stratified by sex, and adjusted for age, sex, smoking, body mass index, education, respiratory diseases and retirement status.

RESULTS

Overall, chronic cough was associated with less SPA, greater HCRU and impaired ADL/IADLs. Productive chronic cough in males was associated with SPA limited by health, ED visits and hospitalisation. Females with productive chronic cough was associated with reduced frequency of SPA and ED visit. Dry chronic cough in females was associated with SPA limited by health and ED visits. Both types of cough was associated with at least 1 impaired basic ADL, but only in females with productive chronic cough was there an association with any impairment in IADLs.

CONCLUSION

Chronic cough is associated with a greater burden on social participation, healthcare use and personal care.

Long-term ambient air pollution exposure and cardio-respiratory disease in China: findings from a prospective cohort study

BACKGROUND

Existing evidence on long-term ambient air pollution (AAP) exposure and risk of cardio-respiratory diseases in China is mainly on mortality, and based on area average concentrations from fixed-site monitors for individual exposures. Substantial uncertainty persists, therefore, about the shape and strength of the relationship when assessed using more personalised individual exposure data. We aimed to examine the relationships between AAP exposure and risk of cardio-respiratory diseases using predicted local levels of AAP.

METHODS

A prospective study included 50,407 participants aged 30-79 years from Suzhou, China, with concentrations of nitrogen dioxide (NO2), sulphur dioxide (SO2), fine (PM2.5), and inhalable (PM10) particulate matter, ozone (O3) and carbon monoxide (CO) and incident cases of cardiovascular disease (CVD) (n = 2,563) and respiratory disease (n = 1,764) recorded during 2013-2015. Cox regression models with time-dependent covariates were used to estimate adjusted hazard ratios (HRs) for diseases associated with local-level concentrations of AAP exposure, estimated using Bayesian spatio-temporal modelling.

RESULTS

The study period of 2013-2015 included a total of 135,199 person-years of follow-up for CVD. There was a positive association of AAP, particularly SO2 and O3, with risk of major cardiovascular and respiratory diseases. Each 10 µg/m3 increase in SO2 was associated with adjusted hazard ratios (HRs) of 1.07 (95% CI: 1.02, 1.12) for CVD, 1.25 (1.08, 1.44) for COPD and 1.12 (1.02, 1.23) for pneumonia. Similarly, each 10 µg/m3 increase in O3 was associated with adjusted HR of 1.02 (1.01, 1.03) for CVD, 1.03 (1.02, 1.05) for all stroke, and 1.04 (1.02, 1.06) for pneumonia.

CONCLUSIONS

Among adults in urban China, long-term exposure to ambient air pollution is associated with a higher risk of cardio-respiratory disease.

Association of the COVID-19 pandemic on stroke admissions and treatment globally: a systematic review

OBJECTIVES

The COVID-19 pandemic has highlighted insufficiencies and gaps within healthcare systems globally. In most countries, including high-income countries, healthcare facilities were over-run and occupied with too few resources beyond capacity. We carried out a systematic review with a primary aim to identify the influence of the COVID-19 pandemic on the presentation and treatment of stroke globally in populations≥65 years of age.

DESIGN

A systematic review was completed. In total, 38 papers were included following full-text screening.

DATA SOURCES

PubMed, MEDLINE and Embase.

ELIGIBILITY CRITERIA

Eligible studies included observational and real-world evidence publications with a population who have experienced stroke treatment during the COVID-19 pandemic. Exclusion criteria included studies comparing the effect of the COVID-19 infection on stroke treatment and outcomes.

DATA EXTRACTION AND SYNTHESIS

Primary outcome measures extracted were the number of admissions, treatment times and patient outcome. Secondary outcomes were severity on admission, population risk factors and destination on discharge. No meta-analysis was performed.

RESULTS

This review demonstrated that 84% of studies reported decreased admissions rates during the COVID-19 pandemic. However, among those admitted, on average, had higher severity of stroke. Additionally, in-hospital stroke treatment pathways were affected by the implementation of COVID-19 protocols, which resulted in increased treatment times in 60% of studies and increased in-hospital mortality in 82% of studies by 100% on average. The prevalence of stroke subtype (ischaemic or haemorrhagic) and primary treatment methods (thrombectomy or thrombolysis) did not vary due to the COVID-19 pandemic.

CONCLUSIONS

During the COVID-19 pandemic, many populations hesitated to seek medical attention, decreasing hospital admissions for less severe strokes and increasing hospitalisation of more severe cases and mortality. The effect of the pandemic on society and healthcare systems needs to be addressed to improve stroke treatment pathways and prepare for potential future epidemics.

PROSPERO REGISTRATION NUMBER

CRD42021248564.

Impact of productive and dry chronic cough on mortality in the Canadian Longitudinal Study on Aging (CLSA)

Background

Chronic cough is a common troublesome condition and accounts for a high burden on quality of life. Previous data investigating the mortality associated with chronic cough has been derived in patients with chronic bronchitis. No data exists on chronic dry cough. Therefore, we investigated if chronic dry and productive cough is independently associated with increased mortality.

Methods

The Canadian Longitudinal Study on Ageing (CLSA) is a prospective, nationally generalizable, stratified random sample of adults aged 45-85 years at baseline recruited between 2011-2015 and followed up three years later. Chronic cough was identified based on a self-reported daily cough in the last 12 months. Deaths were confirmed by the Ministry of Health and/or completion of descendent questionnaire by a family member. Models were investigated for dry and productive chronic cough and was adjusted for age, sex, smoking, body mass index (BMI), and respiratory diseases.

Results

Of the 30,016 participants, 4,783 (15.9%) reported chronic cough at baseline; 2,724 (57%) had a dry cough, and 2,059 (43%) had productive chronic cough. There was a total of 561 deaths between baseline and follow-up-1 (3 years later). There was a 49% higher risk of death in participants with chronic productive cough {adjusted odds ratio (aOR) 1.49 [95% confidence intervals (CI): 1.08-2.07]}, but not dry chronic cough [aOR 0.85 (0.60-1.20)]. The effects of chronic productive cough on mortality were persistent in those with no airflow obstruction [chronic productive cough aOR 1.90 (1.09-3.31)].

Conclusions

Chronic productive cough is associated with a higher risk of death, while chronic dry cough has no impact on mortality risk of death in middle-aged and older adults. This highlights the importance of careful evaluation of patients with chronic cough.

Medicines prescribing for homeless persons: analysis of prescription data from specialist homelessness general practices

Background

Specialist homelessness practices remain the main primary care access point for many persons experiencing homelessness. Prescribing practices are poorly understood in this population.

Objective

This study aims to investigate prescribing of medicines to homeless persons who present to specialist homelessness primary care practices and compares the data with the general population.

Setting

Analyses of publicly available prescribing and demographics data pertaining to primary care in England.

Methods

Prescribing data from 15 specialist homelessness practices in England were extracted for the period 04/2019-03/2020 and compared with data from (a) general populations, (b) the most deprived populations, and (c) the least deprived populations in England.

Main outcome measure

Prescribing rates, measured as the number of items/1000 population in key disease areas.

Results

Data corresponding to 20,572 homeless persons was included. Marked disparity were observed in regards to prescribing rates of drugs for Central Nervous System disorders. For example, prescribing rates were 83-fold (mean (SD) 1296.7(1447.6) vs. 15.7(9.2) p = 0.033) items), and 12-fold (p = 0.018) higher amongst homeless populations for opioid dependence and psychosis disorders respectively compared to the general populations. Differences with populations in the least deprived populations were even higher. Prescribing medicines for other long-term conditions other than mental health and substance misuse was lower in the homeless than in the general population.

Conclusions

Most of the prescribing activities in the homeless population relate to mental health conditions and substance misuse. It is possible that other long-term conditions that overlap with homelessness are under-diagnosed and under-managed. Wide variations in data across practices needs investigation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11096-022-01399-3.

Impact of mental health and personality traits on the incidence of chronic cough in the Canadian Longitudinal Study on Aging

Background

Chronic cough is a common troublesome condition, but risk factors for developing chronic cough are poorly understood. The aim of this study was to understand the relationship between mental health disorders, personality traits and chronic cough.

Methods

The Canadian Longitudinal Study on Aging is a prospective, nationally generalisable, random sample of adults aged 45–85 years at baseline recruited between 2011 and 2015, and followed-up 3 years later. Chronic cough was defined as a daily cough over the last 12 months. Incident chronic cough was defined as those participants who reported new-onset chronic cough between baseline and follow-up 1. Current depressive symptoms and psychological distress were assessed using the Center for Epidemiologic Study Short Depression Scale (CESD-10) and Kessler Psychological Distress Scale (K-10), respectively. The “Big Five” personality traits were assessed using the Ten-Item Personality Inventory. Relative risks are reported using a multivariate mutually adjusted model.

Results

At follow-up 1, 2506 participants (11.1%) reported new-onset chronic cough during the ∼3-year interval. Depressive symptoms (CESD-10 ≥10: relative risk 1.22 (95% CI 1.03–1.44)) and psychological distress (K-10 ≥22: relative risk 1.20 (95% CI 1.07–1.36)) at baseline were both independent predictors of a higher risk of incident chronic cough. Prevalent and incident chronic cough were also independently associated with an increased risk of developing depressive symptoms and psychological distress. Personality traits did not influence the development of chronic cough but did increase the risk of depressive symptoms and psychological distress.

Conclusions

This study shows that there is a bidirectional relationship between chronic cough, and depressive symptoms and psychological distress, and personality traits do not independently influence the development of chronic cough.

Language and Geographical Location influences the Incidence of Chronic Cough in the Canadian Longitudinal Study on Aging (CLSA)

The prevalence of chronic cough is highly variable globally ranging from 2% to 18% [1]. The prevalence was higher in Australia, Europe, America (11–18%) and much lower in Asia (4%) and Africa (2%), even after adjusting for smoking. The majority of the studies used the 3-month chronic bronchitis definition, but even in studies using the same 8-week cut-off, variations still persist: UK (12%) [2], Finland (7.2%) [3], Germany (5%) [4], Denmark (4%) [5], South Korea (2.6%) [6], Japan (2.2%) [7], Nigeria (1.1%) [8]. The reasons for these variations, even in geographically similar countries, are unclear.

French speakers have a 4% lower incidence of chronic cough than English speakers in the CLSA, but English speakers from Quebec, Newfoundland and Labrador, and Nova Scotia also have a lower risk of developing chronic coughhttps://bit.ly/3qAd3Mf

Exposure to household air pollution from solid cookfuels and childhood stunting: a population-based, cross-sectional study of half a million children in low- and middle-income countries

Background

Household air pollution from the incomplete combustion of solid cookfuels in low- and middle-income countries (LMICs) has been largely ignored as a potentially important correlate of stunting. Our objective was to examine the association between solid cookfuel use and stunting in children aged <5 y.

Methods

We used data from 59 LMICs’ population-based cross-sectional demographic and health surveys; 557 098 children aged <5 y were included in our analytical sample. Multilevel logistic regression was used to examine the association between exposure to solid cookfuel use and childhood stunting, adjusting for child sex, age, maternal education and number of children living in the household. We explored the association across key subgroups.

Results

Solid cookfuel use was associated with child stunting (adjusted OR 1.58, 95% CI 1.55 to 1.61). Children living in households using solid cookfuels were more likely to be stunted if they lived in rural areas, the poorest households, had a mother who smoked tobacco or were from the Americas.

Conclusions

Focused strategies to reduce solid cookfuel exposure might contribute to reductions in childhood stunting in LMICs. Trial evidence to assess the effect of reducing solid cookfuel exposure on childhood stunting is urgently needed.

Estimating ambient air pollutant levels in Suzhou through the SPDE approach with R-INLA

Spatio-temporal models of ambient air pollution can be used to predict pollutant levels across a geographical region. These predictions may then be used as estimates of exposure for individuals in analyses of the health effects of air pollution. Integrated nested Laplace approximations is a method for Bayesian inference, and a fast alternative to Markov chain Monte Carlo methods. It also facilitates the SPDE approach to spatial modelling, which has been used for modelling of air pollutant levels, and is available in the R-INLA package for the R statistics software. Covariates such as meteorological variables may be useful predictors in such models, but covariate misalignment must be dealt with. This paper describes a flexible method used to estimate pollutant levels for six pollutants in Suzhou, a city in China with dispersed air pollutant monitors and weather stations. A two-stage approach is used to address misalignment of weather covariate data.

Prevalence, incidence and characteristics of chronic cough among adults from the Canadian Longitudinal Study on Aging

The global prevalence of chronic cough is highly variable, ranging from 2% to 18%. There is a lack of data on the prevalence and incidence of chronic cough in the general population. The objective of this study was to investigate the prevalence and incidence of chronic cough in a sample of Canadian adults, and how these are influenced by age, sex, smoking, respiratory symptoms, medical comorbidities and lung function.

Participants with chronic cough were identified from the Canadian Longitudinal Study on Aging (CLSA) based on self-reported daily cough in the past 12 months. This is a prospective, nationally generalisable, stratified random sample of adults aged 45–85 years at baseline recruited between 2011 and 2015, and followed-up 3 years later. The prevalence and incidence per 100 person-years are described, with adjustments for age, sex and smoking.

Of the 30 097 participants, 29 972 completed the chronic cough question at baseline and 26 701 did so at follow-up. The prevalence of chronic cough was 15.8% at baseline and 17.6% at follow-up with 10.4–17.1% variation across seven provinces included in the CLSA comprehensive sample. Prevalence increased with age and current smoking, and was higher in males (15.2%), Caucasians (14%) and those born in North America, Europe or Oceania (14%). The incidence of chronic cough adjusted for age, sex and smoking was higher in males and in underweight and obese subjects. Subjects with respiratory symptoms, airway diseases, lower forced expiratory volume in 1 s (% predicted), cardiovascular diseases, psychological disorders, diabetes and chronic pain had a higher incidence of chronic cough.

The prevalence and incidence of chronic cough is high in the CLSA sample with geographic, ethnic and gender differences, influenced by a number of medical comorbidities.

Canada has one of the highest prevalences of chronic cough in world and it is more common in Caucasians of European descent. Ageing, smoking, sex, clinical comorbidities and lung physiology all influence the prevalence and incidence of chronic cough.https://bit.ly/3qSBkdp

Chronic productive cough and inhalant occupational exposure-a study of the general population

PURPOSE

Occupational inhalant exposures have been linked with a higher occurrence of chronic productive cough, but recent studies question the association.

METHODS

We included participants from two general population studies, the Copenhagen City General Population Study and the Copenhagen City Heart Study, to assess contemporary (year 2003-2017) and historical (1976-1983) occupational inhalant hazards. Job titles one year prior to study inclusion and an airborne chemical job-exposure matrix (ACE JEM) were used to estimate occupational exposure. The association between occupational exposures and self-reported chronic productive cough was studied using generalized estimating equations stratified by smoking status and cohort.

RESULTS

The population consisted of 5210 working individuals aged 20-65 from 1976 to 1983 and 64,279 from 2003 to 2017. In smokers, exposure to high levels of mineral dust, biological dust, gases & fumes and the composite variable vapours, gases, dusts or fumes (VGDF) were associated with chronic productive cough in both cohorts with odds ratios in the range of 1.2 (95% confidence interval, 1.0;1.4) to 1.6 (1.2;2.1). High levels of biological dust were only associated with an increased risk of a chronic productive cough in the 2003-2017 cohort (OR 1.5 (1.1;2.0)). In non-smokers, high levels of VGDF (OR 1.5 (1.0;2.3)) and low levels of mineral dust (OR 1.7 (1.1;2.4)) were associated with chronic productive cough in the 1976-1983 cohort, while no associations were seen in non-smokers in the 2003-2017 cohort.

CONCLUSION

Occupational inhalant exposure remains associated with a modestly increased risk of a chronic productive cough in smokers, despite declining exposure levels during the past four decades.

Occupational exposures and exacerbations of asthma and COPD-A general population study

Purpose

Recent studies suggest that occupational inhalant exposures trigger exacerbations of asthma and chronic obstructive pulmonary disease, but findings are conflicting.

Methods

We included 7,768 individuals with self-reported asthma (n = 3,215) and/or spirometric airflow limitation (forced expiratory volume in 1 second (FEV₁)/ forced expiratory volume (FVC) <0.70) (n = 5,275) who participated in The Copenhagen City Heart Study or The Copenhagen General Population Study from 2001–2016. Occupational exposure was assigned by linking job codes with job exposure matrices, and exacerbations were defined by register data on oral corticosteroid treatment, emergency care unit assessment or hospital admission. Associations between occupational inhalant exposure each year of follow-up and exacerbation were assessed by Cox regression with time varying exposure and age as the underlying time scale.

Results

Participants were followed for a median of 4.6 years (interquartile range, IQR 5.4), during which 870 exacerbations occurred. Exacerbations were not associated with any of the selected exposures (high molecular weight sensitizers, low molecular weight sensitizers, irritants or low and high levels of mineral dust, biological dust, gases & fumes or the composite variable vapours, gases, dusts or fumes). Hazards ratios ranged from 0.8 (95% confidence interval: 0.7;1.0) to 1.2 (95% confidence interval: 0.9;1.7).

Conclusion

Exacerbations of obstructive airway disease were not associated with occupational inhalant exposures assigned by a job exposure matrix. Further studies with alternative exposure assessment are warranted.

The contribution of FEV1 and airflow limitation on the intensity of dyspnea and leg effort during exercise. Insights from a real-world cohort

RATIONALE

The effort required to cycle and breathe intensify as power increases during incremental exercise. It is currently unclear how changes in FEV1 in the presence or absence of airflow limitation) impacts the intensity of dyspnea and leg effort. This is clinically important as the improvement in FEV1 is often the target for improving dyspnea.

OBJECTIVES

To investigate the relationship between dyspnea (D), leg effort, power (P), and FEV1 with and without airflow limitation using direct psychophysical scaling performed during incremental exercise testing to symptom limited capacity.

METHODS

Retrospective analysis of consecutive patients over the age of 35 referred for cardio-pulmonary exercise testing at McMaster University Medical Centre from 1988-2012.The modified Borg scale was used to measure dyspnea throughout incremental exercise testing.

MEASUREMENTS AND RESULTS

38,788 patients were included in the analysis [Mean Age 58.6 years (SD ±11.8), Males 61%, BMI 28.1 kg/m2 (SD ±5.1), FEV1 was 2.7 L (SD ±0.85), 95% predicted (SD ±20.4), FVC 3.4 L (SD ± 1.0), 94% predicted (SD ±17.0)], and 10.9% had airflow limitation (AL, FEV1 /FVC < 70%). In a nonlinear regression analysis, the intensity of dyspnea increased in a positively accelerating manner with power and as the FEV1 % predicted decreased: Dyspnea = 0.06 * Power1.03  * FEV1 %Pred-0.66 (r = .63). The intensity of leg effort increased with power and declining quadricep strength and FEV1% predicted: Leg Effort = 0.06 * Power1.22  * Quad-0.56 *FEV1 %Pred-0.39 (r = .73). There was no independent effect of AL on dyspnea of leg effort.

CONCLUSION

Power, quadriceps strength and FEV1 are the dominant factors contributing to dyspnea and leg effort, irrespective of the degree of airflow limitation.

Assessment of the Role of Carotid Atherosclerosis in the Association Between Major Cardiovascular Risk Factors and Ischemic Stroke Subtypes

IMPORTANCE

A better understanding of the role of atherosclerosis in the development of ischemic stroke subtypes could help to improve strategies for prevention of stroke worldwide.

OBJECTIVE

To assess the role of carotid atherosclerosis in the association between major cardiovascular risk factors and ischemic stroke subtypes.

DESIGN, SETTING, AND PARTICIPANTS

The prospective China Kadoorie Biobank cohort study was conducted in the general population of 5 urban and 5 rural areas in China, with a baseline survey obtained between June 2004 and July 2008. A random sample of 23 973 participants with no history of cardiovascular disease at enrollment who had carotid artery ultrasonographic measurements recorded at a resurvey from September 2013 to June 2014 were included. Data analysis was performed from July 1, 2016, to April 10, 2019.

EXPOSURES

Major cardiovascular risk factors (ie, blood pressure [BP], blood lipid levels, smoking, and diabetes).

MAIN OUTCOMES AND MEASURES

Carotid ultrasonographic measures of plaque burden (derived from number and maximum size of carotid artery plaques at resurvey) and first ischemic stroke during follow-up (n = 952), with subtyping (data release, August 2018) as lacunar (n = 263), probable large artery (n = 193), probable cardioembolic (n = 66), or unconfirmed (n = 430). Associations between cardiovascular risk factors, carotid plaque burden, and ischemic stroke subtypes were adjusted for age, sex, and geographic area.

RESULTS

The 23 973 participants in the study had a mean (SD) age of 50.6 (10.0) years, and 14 833 (61.9%) were women. Systolic BP had a stronger association (odds ratio [OR] per SD, 1.51; 95% CI, 1.42-1.61) than plaque burden (OR per SD, 1.34; 95% CI, 1.26-1.44) with ischemic stroke, and the associations of systolic BP with each subtype of ischemic stroke were modestly attenuated by adjustment for plaque burden. After adjustment for BP, plaque burden had a stronger association with probable large artery stroke (OR, 1.43; 95% CI, 1.24-1.63) than with lacunar stroke (OR, 1.25; 95% CI, 1.10-1.43) but was not associated with probable cardioembolic stroke (OR, 1.06; 95% CI, 0.83-1.36).

CONCLUSIONS AND RELEVANCE

Although BP was an important risk factor for all ischemic stroke subtypes, carotid atherosclerosis was an important risk factor only for large artery and lacunar strokes, suggesting that drug treatments targeting atherosclerosis may reduce the risk of stroke subtypes to different extents.

Cardiorespiratory health effects of gaseous ambient air pollution exposure in low and middle income countries: a systematic review and meta-analysis

BACKGROUND

Lack of research on the effects of gaseous pollutants (nitrogen oxides [NO_x], sulfur dioxide [SO₂], carbon monoxide [CO] and ozone [O₃]) in the ambient environment on health outcomes from within low and middle income countries (LMICs) is leading to reliance on results from studies performed within high income countries (HICs). This systematic review and meta-analysis examines the cardiorespiratory health effects of gaseous pollutants in LMICs exclusively.

METHODS

Systematic searching was carried out and estimates pooled by pollutant, lag and outcome, and presented as excess relative risk per 10 μg/m³ (NO_x, SO₂, O₃) or 1 ppm (CO) increase pollutant. Sub-group analysis was performed examining estimates by specific outcomes, city and co-pollutant adjustment.

RESULTS

Sixty studies met the inclusion criteria, most (44) from the East Asia and Pacific region. A 10 μg/m³ increase in same day NOx was associated with 0.92% (95% CI: 0.44, 1.39), and 0.70% (0.01, 1.40) increases in cardiovascular and respiratory mortality respectively, same day NO_x was not associated with morbidity. Same day sulfur dioxide was associated with 0.73% (0.04, 1.42) and 0.50% (0.01, 1.00) increases in respiratory morbidity and in cardiovascular mortality respectively.

CONCLUSIONS

Acute exposure to gaseous ambient air pollution (AAP) is associated with increases in morbidity and mortality in LMICs, with greatest associations observed for cardiorespiratory mortality.

Burden of carotid artery atherosclerosis in Chinese adults: Implications for future risk of cardiovascular diseases

Background Population-based studies of ultrasound measures of carotid atherosclerosis are informative about future risks of cardiovascular disease. Design Cross-sectional studies of carotid artery atherosclerosis in 24,822 Chinese adults from the China Kadoorie Biobank and 2579 Europeans from the UK Biobank. Methods Mean intima-media thickness of the common carotid arteries and presence of carotid artery plaque were examined in the China Kadoorie Biobank study. The carotid intima-media thickness (cIMT) findings in Chinese (mean age 59 years) were compared with a European population (mean age 62 years). Results Overall, the mean cIMT in Chinese was 0.70 mm (SD 0.16) and increased with age by 0.08 mm (SE 0.008) per 10-years older age. About 31% of the Chinese had carotid plaques and the prevalence varied 10-fold with age (6% at 40-49 to 63% at 70-89 years) and four-fold by region (range, 14%-57%). After adjustment for age, sex and region, plaque prevalence was higher in smokers than in non-smokers (36% vs. 28%) and two-fold higher in individuals with systolic blood pressure ≥160 mmHg than those with systolic blood pressure <120 mmHg (44% vs. 22%) in the China Kadoorie Biobank study. Mean cIMT was similar in the younger Chinese and European adults, but increased more steeply with age in the Chinese ( p = 0.002). Conclusions About one-third of Chinese adults had carotid plaques. The rate of progression of carotid atherosclerosis with age was more extreme in the Chinese compared with the European population, highlighting the need for more intensive strategies for cardiovascular disease prevention in China.

Informed Consent in Health Research: Challenges and Barriers in Low-and Middle-Income Countries with Specific Reference to Nepal

Obtaining 'informed consent' from every individual participant involved in health research is a mandatory ethical practice. Informed consent is a process whereby potential participants are genuinely informed about their role, risk and rights before they are enrolled in the study. Thus, ethics committees in most countries require 'informed consent form' as part of an ethics application which is reviewed before granting research ethics approval. Despite a significant increase in health research activity in low-and middle-income countries (LMICs) in recent years, only limited work has been done to address ethical concerns. Most ethics committees in LMICs lack the authority and/or the capacity to monitor research in the field. This is important since not all research, particularly in LMICs region, complies with ethical principles, sometimes this is inadvertently or due to a lack of awareness of their importance in assuring proper research governance. With several examples from Nepal, this paper reflects on the steps required to obtain informed consents and highlights some of the major challenges and barriers to seeking informed consent from research participants. At the end of this paper, we also offer some recommendations around how can we can promote and implement optimal informed consent taking process. We believe that paper is useful for researchers and members of ethical review boards in highlighting key issues around informed consent.

Prevalence and correlates of airflow obstruction in ∼317,000 never-smokers in China

In China, the burden of chronic obstructive disease (COPD) is high in never-smokers but little is known about its causes in this group. We analysed data on 287 000 female and 30 000 male never-smokers aged 30-79 years from 10 regions in China, who participated in the China Kadoorie Biobank baseline survey (2004-2008). Prevalence of airflow obstruction (AFO) (pre-bronchodilator forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) <0.7 and below the lower limit of normal (LLN)) was estimated, by age and region. Cross-sectional associations of AFO (FEV1/FVC <0.7), adjusted for confounding, were examined. AFO prevalence defined as FEV1/FVC <0.7 was 4.0% in females and 5.1% in males (mean ages 51 and 54 years, respectively). AFO prevalence defined as FEV1/FVC Collapse

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MESH Headings

• Adult
• Aged
• Air Pollution, Indoor
• Asthma/diagnosis
• Asthma/epidemiology
• Body Mass Index
• China
• Cooking
• Cross-Sectional Studies
• Female
• Forced Expiratory Volume
• Humans
• Male
• Middle Aged
• Odds Ratio
• Prevalence
• Pulmonary Disease, Chronic Obstructive/diagnosis
• Pulmonary Disease, Chronic Obstructive/epidemiology
• Respiration
• Smoking
• Spirometry
• Surveys and Questionnaires
• Vital Capacity

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Grants

• Wellcome Trust
• MC_U137686851 Medical Research Council

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Affiliation(s)

Margaret Smith Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), University of Oxford, Oxford, UK
Liming Li Chinese Academy of Medical Sciences, Beijing School of Public Health, Peking University Health Sciences Center, Beijing
Mareli Augustyn Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), University of Oxford, Oxford, UK
Om Kurmi Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), University of Oxford, Oxford, UK
Junshi Chen China National Center for Food Safety Risk Assessment, Beijing
Rory Collins Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), University of Oxford, Oxford, UK
Yu Guo Chinese Academy of Medical Sciences, Beijing
Yabin Han Tongxiang Center for Disease Control, Tongxiang
Jingxin Qin Liuzhou Center for Disease Control, Liuzhou
Guanqun Xu Suzhou Center for Disease Control, Suzhou
Jian Wang Pengzhou Center for Disease Control, Pengzhou
Zheng Bian Chinese Academy of Medical Sciences, Beijing
Gang Zhou Henan Center for Disease Control, Zhengzhou, China
Richard Peto Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), University of Oxford, Oxford, UK
Zhengming Chen Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), University of Oxford, Oxford, UK

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Regional variations in the prevalence and misdiagnosis of air flow obstruction in China: baseline results from a prospective cohort of the China Kadoorie Biobank (CKB)

Background

Despite the great burden of chronic respiratory diseases in China, few large multicentre, spirometry-based studies have examined its prevalence, rate of underdiagnosis regionally or the relevance of socioeconomic and lifestyle factors.

Methods

We analysed data from 512 891 adults in the China Kadoorie Biobank, recruited from 10 diverse regions of China during 2004–2008. Air flow obstruction (AFO) was defined by the lower limit of normal criteria based on spirometry-measured lung function. The prevalence of AFO was analysed by region, age, socioeconomic status, body mass index (BMI) and smoking history and compared with the prevalence of self-reported physician-diagnosed chronic bronchitis or emphysema (CB/E) and its symptoms.

Findings

The prevalence of AFO was 7.3% in men (range 2.5–18.2%) and 6.4% in women (1.5–18.5%). Higher prevalence of AFO was associated with older age (p<0.0001), lower income (p<0.0001), poor education (p<0.001), living in rural regions (p<0.001), those who started smoking before the age of 20 years (p<0.001) and low BMI (p<0.001). Compared with self-reported diagnosis of CB/E, 88.8% of AFO was underdiagnosed; underdiagnosis proportion was highest in 30–39-year olds (96.7%) compared with the 70+ age group (81.1%), in women (90.7%), in urban areas (89.4%), in people earning 5K–10 K ¥ monthly (90.3%) and in those with middle or high school education (92.6%).

Interpretation

In China, the burden of AFO based on spirometry was high and significantly greater than that estimated based on self-reported physician-diagnosed CB/E, especially in rural areas, reflecting major issues with diagnosis of AFO that will impact disease treatment and management.

Exhaled carbon monoxide and its associations with smoking, indoor household air pollution and chronic respiratory diseases among 512,000 Chinese adults

BACKGROUND

Exhaled carbon monoxide (COex) level is positively associated with tobacco smoking and exposure to smoke from biomass/coal burning. Relatively little is known about its determinants in China despite the population having a high prevalence of smoking and use of biomass/coal.

METHODS

The China Kadoorie Biobank includes 512,000 participants aged 30-79 years recruited from 10 diverse regions. We used linear regression and logistic regression methods to assess the associations of COex level with smoking, exposures to indoor household air pollution and prevalent chronic respiratory conditions among never smokers, both overall and by seasons, regions and smoking status.

RESULTS

The overall COex level (ppm) was much higher in current smokers than in never smokers (men: 11.5 vs 3.7; women: 9.3 vs 3.2). Among current smokers, it was higher among those who smoked more and inhaled more deeply. Among never smokers, mean COex was positively associated with levels of exposures to passive smoking and to biomass/coal burning, especially in rural areas and during winter. The odds ratios (OR) and 95% confidence interval (CI) of air flow obstruction (FEV1/FVC ratio<0.7) for never smokers with COex at 7-14 and ≥14 ppm, compared with those having COex<7, were 1.38 (1.31-1.45) and 1.65 (1.52-1.80), respectively (Ptrend<0.001). Prevalence of other self-reported chronic respiratory conditions was also higher among people with elevated COex (P<0.05).

CONCLUSION

In adult Chinese, COex can be used as a biomarker for assessing current smoking and overall exposure to indoor household air pollution in combination with questionnaires.