Clinical scenarios of HCM-related mortality: relevance of age and stage of disease at presentation

 

In the early days, Hypertrophic cardiomyopathy (HCM) has long been considered a malignant disease.

However, contemporary descriptions of HCM report low mortality rates, largely due to heart failure-related complications (HF), while sudden cardiac death (SCD) rates are consistently low. Ageing with HCM is not uncommon and competing risk of acquired cardiovascular (CV) and non-CV diseases becomes relevant over time.

Purpose

To describe the disease stage at presentation and the modes of death in a cohort of consecutive HCM patients followed at a national referral centre over the last two decades. Stages of disease were defined according to Circ. Heart Fail. 2012, as follows:

1) “Classic HCM phenotype” characterized by LV ejection fraction (EF) >65%.

2) “Adverse remodeling” characterized by LVEF in the range of 50% to 65%.

3) “Overt dysfunction” is the end-stage clinical evolution characterized by a LVEF <50%.

Methods

By searching our centralized database, we identified 1491 HCM patients with at least >1 year of follow-up between January 2000 and December 2020, 191 of whom died in the same period. In 30 the cause of death could not be ascertained. The remaining 161 constituted our study cohort.

Results

Of the 161 patients who died, 103 (64%) died due to HCM-related causes, whereas 58 (36%) died from non-HCM-related causes such as coronary artery disease (other CV) or other non CV causes.

Modes of death varied based on the stage of disease at diagnosis:

– Fifty-six (35%) patients had a “classic” HCM phenotype at diagnosis. Of these, about half died of HCM-related causes (n=30; 54%), versus 45% with non-HCM-related death. Differently from the other 2 stages, the single most common cause of death was “other non-CV related” mortality, in 44%. Among HCM-related causes, SCD prevailed (n=15; 27%) while HF-related events were only 8 (14%).

– Of the 86 (53%) patients with “adverse remodeling” at diagnosis, more than half died of HCM-related causes (n=57, 66%), largely due to HF (n=33, 38%); SCD occurred in 18 (21%) individuals. This stage included the highest percentage of patients who died of stroke (n=6; 7%).

– Of the 19 (12%) patients in “overt dysfunction” at diagnosis, HF represented the cause of demise in almost three quarters (n=14, 74%); SCD and non-HCM causes accounted for only 10% and 16% respectively.

Conclusions

Most HCM patients die due to complications of their own disease, mainly in the context of HF. Modes of death vary with the stage of disease, with SCD becoming less prevalent in more advanced phases of progression, when competitive risks of HF-related events become overwhelming. These data highlight an unmet medical need in the prevention of disease progression associated with HCM.

Funding Acknowledgement

Type of funding sources: None.

Estimates, trends, and drivers of the global burden of type 2 diabetes attributable to PM2·5 air pollution, 1990-2019: an analysis of data from the Global Burden of Disease Study 2019

BACKGROUND

Experimental and epidemiological studies indicate an association between exposure to particulate matter (PM) air pollution and increased risk of type 2 diabetes. In view of the high and increasing prevalence of diabetes, we aimed to quantify the burden of type 2 diabetes attributable to PM2·5 originating from ambient and household air pollution.

METHODS

We systematically compiled all relevant cohort and case-control studies assessing the effect of exposure to household and ambient fine particulate matter (PM2·5) air pollution on type 2 diabetes incidence and mortality. We derived an exposure-response curve from the extracted relative risk estimates using the MR-BRT (meta-regression-Bayesian, regularised, trimmed) tool. The estimated curve was linked to ambient and household PM2·5 exposures from the Global Burden of Diseases, Injuries, and Risk Factors Study 2019, and estimates of the attributable burden (population attributable fractions and rates per 100 000 population of deaths and disability-adjusted life-years) for 204 countries from 1990 to 2019 were calculated. We also assessed the role of changes in exposure, population size, age, and type 2 diabetes incidence in the observed trend in PM2·5-attributable type 2 diabetes burden. All estimates are presented with 95% uncertainty intervals.

FINDINGS

In 2019, approximately a fifth of the global burden of type 2 diabetes was attributable to PM2·5 exposure, with an estimated 3·78 (95% uncertainty interval 2·68-4·83) deaths per 100 000 population and 167 (117-223) disability-adjusted life-years (DALYs) per 100 000 population. Approximately 13·4% (9·49-17·5) of deaths and 13·6% (9·73-17·9) of DALYs due to type 2 diabetes were contributed by ambient PM2·5, and 6·50% (4·22-9·53) of deaths and 5·92% (3·81-8·64) of DALYs by household air pollution. High burdens, in terms of numbers as well as rates, were estimated in Asia, sub-Saharan Africa, and South America. Since 1990, the attributable burden has increased by 50%, driven largely by population growth and ageing. Globally, the impact of reductions in household air pollution was largely offset by increased ambient PM2·5.

INTERPRETATION

Air pollution is a major risk factor for diabetes. We estimated that about a fifth of the global burden of type 2 diabetes is attributable PM2·5 pollution. Air pollution mitigation therefore might have an essential role in reducing the global disease burden resulting from type 2 diabetes.

FUNDING

Bill & Melinda Gates Foundation.

Association between air pollution, body mass index, respiratory symptoms, and asthma among adolescent school children living in Delhi, India

Background:

Delhi is one of the most polluted cities in the world with annual average ambient PM₁₀ and PM_2.5 levels exceeding the World Health Organization standards by over 15 fold. We aimed to study the prevalence of respiratory and allergic symptoms and asthma among adolescent children living in Delhi (D) and compare it with children living in lesser polluted cities of Kottayam (K) and Mysore (M) located in Southern India.

Methods:

4361 boys and girls between the age group of 13–14 and 16–17 years from 12 randomly selected private schools from D, K, and M were invited to participate. Modified and expanded International Study for Asthma and Allergies in Children (ISAAC) questionnaires (Q) were filled by the students who also performed spirometry using the ultrasonic flow-sensor-based nDD Spirometer.

Results:

3157 students (50.4% boys) completed the Q and performed good quality spirometry. The prevalence of asthma and airflow obstruction among children living in Delhi was 21.7% using the ISAAC Q and 29.4% on spirometry, respectively. This was accompanied by significantly higher rates of self-reported cough, shortness of breath, chest tightness, sneezing, itchy and watery eyes, itchy skin, and eczema among Delhi children (vs. K-M, all P < 0.05). Delhi children were more overweight and obese (39.8% vs. 16.4%, P < 0.0001), and this was the only risk factor that was strongly associated with asthma (odds ratio [OR]: 1.79; confidence interval: 1.49–2.14), with a more pronounced effect in Delhi children (P = 0.04). Forced expiratory volume₁ and Forced vital capacity values were significantly higher in Delhi children (vs. K-M P < 0.0001). Preserved ratio impaired spirometry was more common in K-M children (P < 0.0001).

Conclusion:

Adolescent children living in the polluted city of Delhi had a high prevalence of asthma, respiratory symptoms, allergic rhinitis, and eczema that was strongly associated with a high body mass index (BMI). Our study suggests an association between air pollution, high BMI, and asthma/allergic diseases, which needs to be explored further.

Global, regional, and national age-sex-specific mortality for 282 causes of death in 195 countries and territories, 1980-2017: a systematic analysis for the Global Burden of Disease Study 2017

BACKGROUND

Global development goals increasingly rely on country-specific estimates for benchmarking a nation's progress. To meet this need, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2016 estimated global, regional, national, and, for selected locations, subnational cause-specific mortality beginning in the year 1980. Here we report an update to that study, making use of newly available data and improved methods. GBD 2017 provides a comprehensive assessment of cause-specific mortality for 282 causes in 195 countries and territories from 1980 to 2017.

METHODS

The causes of death database is composed of vital registration (VR), verbal autopsy (VA), registry, survey, police, and surveillance data. GBD 2017 added ten VA studies, 127 country-years of VR data, 502 cancer-registry country-years, and an additional surveillance country-year. Expansions of the GBD cause of death hierarchy resulted in 18 additional causes estimated for GBD 2017. Newly available data led to subnational estimates for five additional countries-Ethiopia, Iran, New Zealand, Norway, and Russia. Deaths assigned International Classification of Diseases (ICD) codes for non-specific, implausible, or intermediate causes of death were reassigned to underlying causes by redistribution algorithms that were incorporated into uncertainty estimation. We used statistical modelling tools developed for GBD, including the Cause of Death Ensemble model (CODEm), to generate cause fractions and cause-specific death rates for each location, year, age, and sex. Instead of using UN estimates as in previous versions, GBD 2017 independently estimated population size and fertility rate for all locations. Years of life lost (YLLs) were then calculated as the sum of each death multiplied by the standard life expectancy at each age. All rates reported here are age-standardised.

FINDINGS

At the broadest grouping of causes of death (Level 1), non-communicable diseases (NCDs) comprised the greatest fraction of deaths, contributing to 73·4% (95% uncertainty interval [UI] 72·5-74·1) of total deaths in 2017, while communicable, maternal, neonatal, and nutritional (CMNN) causes accounted for 18·6% (17·9-19·6), and injuries 8·0% (7·7-8·2). Total numbers of deaths from NCD causes increased from 2007 to 2017 by 22·7% (21·5-23·9), representing an additional 7·61 million (7·20-8·01) deaths estimated in 2017 versus 2007. The death rate from NCDs decreased globally by 7·9% (7·0-8·8). The number of deaths for CMNN causes decreased by 22·2% (20·0-24·0) and the death rate by 31·8% (30·1-33·3). Total deaths from injuries increased by 2·3% (0·5-4·0) between 2007 and 2017, and the death rate from injuries decreased by 13·7% (12·2-15·1) to 57·9 deaths (55·9-59·2) per 100 000 in 2017. Deaths from substance use disorders also increased, rising from 284 000 deaths (268 000-289 000) globally in 2007 to 352 000 (334 000-363 000) in 2017. Between 2007 and 2017, total deaths from conflict and terrorism increased by 118·0% (88·8-148·6). A greater reduction in total deaths and death rates was observed for some CMNN causes among children younger than 5 years than for older adults, such as a 36·4% (32·2-40·6) reduction in deaths from lower respiratory infections for children younger than 5 years compared with a 33·6% (31·2-36·1) increase in adults older than 70 years. Globally, the number of deaths was greater for men than for women at most ages in 2017, except at ages older than 85 years. Trends in global YLLs reflect an epidemiological transition, with decreases in total YLLs from enteric infections, respiratory infections and tuberculosis, and maternal and neonatal disorders between 1990 and 2017; these were generally greater in magnitude at the lowest levels of the Socio-demographic Index (SDI). At the same time, there were large increases in YLLs from neoplasms and cardiovascular diseases. YLL rates decreased across the five leading Level 2 causes in all SDI quintiles. The leading causes of YLLs in 1990-neonatal disorders, lower respiratory infections, and diarrhoeal diseases-were ranked second, fourth, and fifth, in 2017. Meanwhile, estimated YLLs increased for ischaemic heart disease (ranked first in 2017) and stroke (ranked third), even though YLL rates decreased. Population growth contributed to increased total deaths across the 20 leading Level 2 causes of mortality between 2007 and 2017. Decreases in the cause-specific mortality rate reduced the effect of population growth for all but three causes: substance use disorders, neurological disorders, and skin and subcutaneous diseases.

INTERPRETATION

Improvements in global health have been unevenly distributed among populations. Deaths due to injuries, substance use disorders, armed conflict and terrorism, neoplasms, and cardiovascular disease are expanding threats to global health. For causes of death such as lower respiratory and enteric infections, more rapid progress occurred for children than for the oldest adults, and there is continuing disparity in mortality rates by sex across age groups. Reductions in the death rate of some common diseases are themselves slowing or have ceased, primarily for NCDs, and the death rate for selected causes has increased in the past decade.

FUNDING

Bill & Melinda Gates Foundation.

Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017

BACKGROUND

The Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017) includes a comprehensive assessment of incidence, prevalence, and years lived with disability (YLDs) for 354 causes in 195 countries and territories from 1990 to 2017. Previous GBD studies have shown how the decline of mortality rates from 1990 to 2016 has led to an increase in life expectancy, an ageing global population, and an expansion of the non-fatal burden of disease and injury. These studies have also shown how a substantial portion of the world's population experiences non-fatal health loss with considerable heterogeneity among different causes, locations, ages, and sexes. Ongoing objectives of the GBD study include increasing the level of estimation detail, improving analytical strategies, and increasing the amount of high-quality data.

METHODS

We estimated incidence and prevalence for 354 diseases and injuries and 3484 sequelae. We used an updated and extensive body of literature studies, survey data, surveillance data, inpatient admission records, outpatient visit records, and health insurance claims, and additionally used results from cause of death models to inform estimates using a total of 68 781 data sources. Newly available clinical data from India, Iran, Japan, Jordan, Nepal, China, Brazil, Norway, and Italy were incorporated, as well as updated claims data from the USA and new claims data from Taiwan (province of China) and Singapore. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between rates of incidence, prevalence, remission, and cause of death for each condition. YLDs were estimated as the product of a prevalence estimate and a disability weight for health states of each mutually exclusive sequela, adjusted for comorbidity. We updated the Socio-demographic Index (SDI), a summary development indicator of income per capita, years of schooling, and total fertility rate. Additionally, we calculated differences between male and female YLDs to identify divergent trends across sexes. GBD 2017 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting.

FINDINGS

Globally, for females, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and haemoglobinopathies and haemolytic anaemias in both 1990 and 2017. For males, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and tuberculosis including latent tuberculosis infection in both 1990 and 2017. In terms of YLDs, low back pain, headache disorders, and dietary iron deficiency were the leading Level 3 causes of YLD counts in 1990, whereas low back pain, headache disorders, and depressive disorders were the leading causes in 2017 for both sexes combined. All-cause age-standardised YLD rates decreased by 3·9% (95% uncertainty interval [UI] 3·1-4·6) from 1990 to 2017; however, the all-age YLD rate increased by 7·2% (6·0-8·4) while the total sum of global YLDs increased from 562 million (421-723) to 853 million (642-1100). The increases for males and females were similar, with increases in all-age YLD rates of 7·9% (6·6-9·2) for males and 6·5% (5·4-7·7) for females. We found significant differences between males and females in terms of age-standardised prevalence estimates for multiple causes. The causes with the greatest relative differences between sexes in 2017 included substance use disorders (3018 cases [95% UI 2782-3252] per 100 000 in males vs s1400 [1279-1524] per 100 000 in females), transport injuries (3322 [3082-3583] vs 2336 [2154-2535]), and self-harm and interpersonal violence (3265 [2943-3630] vs 5643 [5057-6302]).

INTERPRETATION

Global all-cause age-standardised YLD rates have improved only slightly over a period spanning nearly three decades. However, the magnitude of the non-fatal disease burden has expanded globally, with increasing numbers of people who have a wide spectrum of conditions. A subset of conditions has remained globally pervasive since 1990, whereas other conditions have displayed more dynamic trends, with different ages, sexes, and geographies across the globe experiencing varying burdens and trends of health loss. This study emphasises how global improvements in premature mortality for select conditions have led to older populations with complex and potentially expensive diseases, yet also highlights global achievements in certain domains of disease and injury.

FUNDING

Bill & Melinda Gates Foundation.

Global, regional, and national age-sex-specific mortality for 282 causes of death in 195 countries and territories, 1980-2017: a systematic analysis for the Global Burden of Disease Study 2017

BACKGROUND

Global development goals increasingly rely on country-specific estimates for benchmarking a nation's progress. To meet this need, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2016 estimated global, regional, national, and, for selected locations, subnational cause-specific mortality beginning in the year 1980. Here we report an update to that study, making use of newly available data and improved methods. GBD 2017 provides a comprehensive assessment of cause-specific mortality for 282 causes in 195 countries and territories from 1980 to 2017.

METHODS

The causes of death database is composed of vital registration (VR), verbal autopsy (VA), registry, survey, police, and surveillance data. GBD 2017 added ten VA studies, 127 country-years of VR data, 502 cancer-registry country-years, and an additional surveillance country-year. Expansions of the GBD cause of death hierarchy resulted in 18 additional causes estimated for GBD 2017. Newly available data led to subnational estimates for five additional countries-Ethiopia, Iran, New Zealand, Norway, and Russia. Deaths assigned International Classification of Diseases (ICD) codes for non-specific, implausible, or intermediate causes of death were reassigned to underlying causes by redistribution algorithms that were incorporated into uncertainty estimation. We used statistical modelling tools developed for GBD, including the Cause of Death Ensemble model (CODEm), to generate cause fractions and cause-specific death rates for each location, year, age, and sex. Instead of using UN estimates as in previous versions, GBD 2017 independently estimated population size and fertility rate for all locations. Years of life lost (YLLs) were then calculated as the sum of each death multiplied by the standard life expectancy at each age. All rates reported here are age-standardised.

FINDINGS

At the broadest grouping of causes of death (Level 1), non-communicable diseases (NCDs) comprised the greatest fraction of deaths, contributing to 73·4% (95% uncertainty interval [UI] 72·5-74·1) of total deaths in 2017, while communicable, maternal, neonatal, and nutritional (CMNN) causes accounted for 18·6% (17·9-19·6), and injuries 8·0% (7·7-8·2). Total numbers of deaths from NCD causes increased from 2007 to 2017 by 22·7% (21·5-23·9), representing an additional 7·61 million (7·20-8·01) deaths estimated in 2017 versus 2007. The death rate from NCDs decreased globally by 7·9% (7·0-8·8). The number of deaths for CMNN causes decreased by 22·2% (20·0-24·0) and the death rate by 31·8% (30·1-33·3). Total deaths from injuries increased by 2·3% (0·5-4·0) between 2007 and 2017, and the death rate from injuries decreased by 13·7% (12·2-15·1) to 57·9 deaths (55·9-59·2) per 100 000 in 2017. Deaths from substance use disorders also increased, rising from 284 000 deaths (268 000-289 000) globally in 2007 to 352 000 (334 000-363 000) in 2017. Between 2007 and 2017, total deaths from conflict and terrorism increased by 118·0% (88·8-148·6). A greater reduction in total deaths and death rates was observed for some CMNN causes among children younger than 5 years than for older adults, such as a 36·4% (32·2-40·6) reduction in deaths from lower respiratory infections for children younger than 5 years compared with a 33·6% (31·2-36·1) increase in adults older than 70 years. Globally, the number of deaths was greater for men than for women at most ages in 2017, except at ages older than 85 years. Trends in global YLLs reflect an epidemiological transition, with decreases in total YLLs from enteric infections, respiratory infections and tuberculosis, and maternal and neonatal disorders between 1990 and 2017; these were generally greater in magnitude at the lowest levels of the Socio-demographic Index (SDI). At the same time, there were large increases in YLLs from neoplasms and cardiovascular diseases. YLL rates decreased across the five leading Level 2 causes in all SDI quintiles. The leading causes of YLLs in 1990-neonatal disorders, lower respiratory infections, and diarrhoeal diseases-were ranked second, fourth, and fifth, in 2017. Meanwhile, estimated YLLs increased for ischaemic heart disease (ranked first in 2017) and stroke (ranked third), even though YLL rates decreased. Population growth contributed to increased total deaths across the 20 leading Level 2 causes of mortality between 2007 and 2017. Decreases in the cause-specific mortality rate reduced the effect of population growth for all but three causes: substance use disorders, neurological disorders, and skin and subcutaneous diseases.

INTERPRETATION

Improvements in global health have been unevenly distributed among populations. Deaths due to injuries, substance use disorders, armed conflict and terrorism, neoplasms, and cardiovascular disease are expanding threats to global health. For causes of death such as lower respiratory and enteric infections, more rapid progress occurred for children than for the oldest adults, and there is continuing disparity in mortality rates by sex across age groups. Reductions in the death rate of some common diseases are themselves slowing or have ceased, primarily for NCDs, and the death rate for selected causes has increased in the past decade.

FUNDING

Bill & Melinda Gates Foundation.

Measuring progress from 1990 to 2017 and projecting attainment to 2030 of the health-related Sustainable Development Goals for 195 countries and territories: a systematic analysis for the Global Burden of Disease Study 2017

BACKGROUND

Efforts to establish the 2015 baseline and monitor early implementation of the UN Sustainable Development Goals (SDGs) highlight both great potential for and threats to improving health by 2030. To fully deliver on the SDG aim of "leaving no one behind", it is increasingly important to examine the health-related SDGs beyond national-level estimates. As part of the Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017), we measured progress on 41 of 52 health-related SDG indicators and estimated the health-related SDG index for 195 countries and territories for the period 1990-2017, projected indicators to 2030, and analysed global attainment.

METHODS

We measured progress on 41 health-related SDG indicators from 1990 to 2017, an increase of four indicators since GBD 2016 (new indicators were health worker density, sexual violence by non-intimate partners, population census status, and prevalence of physical and sexual violence [reported separately]). We also improved the measurement of several previously reported indicators. We constructed national-level estimates and, for a subset of health-related SDGs, examined indicator-level differences by sex and Socio-demographic Index (SDI) quintile. We also did subnational assessments of performance for selected countries. To construct the health-related SDG index, we transformed the value for each indicator on a scale of 0-100, with 0 as the 2·5th percentile and 100 as the 97·5th percentile of 1000 draws calculated from 1990 to 2030, and took the geometric mean of the scaled indicators by target. To generate projections through 2030, we used a forecasting framework that drew estimates from the broader GBD study and used weighted averages of indicator-specific and country-specific annualised rates of change from 1990 to 2017 to inform future estimates. We assessed attainment of indicators with defined targets in two ways: first, using mean values projected for 2030, and then using the probability of attainment in 2030 calculated from 1000 draws. We also did a global attainment analysis of the feasibility of attaining SDG targets on the basis of past trends. Using 2015 global averages of indicators with defined SDG targets, we calculated the global annualised rates of change required from 2015 to 2030 to meet these targets, and then identified in what percentiles the required global annualised rates of change fell in the distribution of country-level rates of change from 1990 to 2015. We took the mean of these global percentile values across indicators and applied the past rate of change at this mean global percentile to all health-related SDG indicators, irrespective of target definition, to estimate the equivalent 2030 global average value and percentage change from 2015 to 2030 for each indicator.

FINDINGS

The global median health-related SDG index in 2017 was 59·4 (IQR 35·4-67·3), ranging from a low of 11·6 (95% uncertainty interval 9·6-14·0) to a high of 84·9 (83·1-86·7). SDG index values in countries assessed at the subnational level varied substantially, particularly in China and India, although scores in Japan and the UK were more homogeneous. Indicators also varied by SDI quintile and sex, with males having worse outcomes than females for non-communicable disease (NCD) mortality, alcohol use, and smoking, among others. Most countries were projected to have a higher health-related SDG index in 2030 than in 2017, while country-level probabilities of attainment by 2030 varied widely by indicator. Under-5 mortality, neonatal mortality, maternal mortality ratio, and malaria indicators had the most countries with at least 95% probability of target attainment. Other indicators, including NCD mortality and suicide mortality, had no countries projected to meet corresponding SDG targets on the basis of projected mean values for 2030 but showed some probability of attainment by 2030. For some indicators, including child malnutrition, several infectious diseases, and most violence measures, the annualised rates of change required to meet SDG targets far exceeded the pace of progress achieved by any country in the recent past. We found that applying the mean global annualised rate of change to indicators without defined targets would equate to about 19% and 22% reductions in global smoking and alcohol consumption, respectively; a 47% decline in adolescent birth rates; and a more than 85% increase in health worker density per 1000 population by 2030.

INTERPRETATION

The GBD study offers a unique, robust platform for monitoring the health-related SDGs across demographic and geographic dimensions. Our findings underscore the importance of increased collection and analysis of disaggregated data and highlight where more deliberate design or targeting of interventions could accelerate progress in attaining the SDGs. Current projections show that many health-related SDG indicators, NCDs, NCD-related risks, and violence-related indicators will require a concerted shift away from what might have driven past gains-curative interventions in the case of NCDs-towards multisectoral, prevention-oriented policy action and investments to achieve SDG aims. Notably, several targets, if they are to be met by 2030, demand a pace of progress that no country has achieved in the recent past. The future is fundamentally uncertain, and no model can fully predict what breakthroughs or events might alter the course of the SDGs. What is clear is that our actions-or inaction-today will ultimately dictate how close the world, collectively, can get to leaving no one behind by 2030.

FUNDING

Bill & Melinda Gates Foundation.

Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017

BACKGROUND

The Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017) includes a comprehensive assessment of incidence, prevalence, and years lived with disability (YLDs) for 354 causes in 195 countries and territories from 1990 to 2017. Previous GBD studies have shown how the decline of mortality rates from 1990 to 2016 has led to an increase in life expectancy, an ageing global population, and an expansion of the non-fatal burden of disease and injury. These studies have also shown how a substantial portion of the world's population experiences non-fatal health loss with considerable heterogeneity among different causes, locations, ages, and sexes. Ongoing objectives of the GBD study include increasing the level of estimation detail, improving analytical strategies, and increasing the amount of high-quality data.

METHODS

We estimated incidence and prevalence for 354 diseases and injuries and 3484 sequelae. We used an updated and extensive body of literature studies, survey data, surveillance data, inpatient admission records, outpatient visit records, and health insurance claims, and additionally used results from cause of death models to inform estimates using a total of 68 781 data sources. Newly available clinical data from India, Iran, Japan, Jordan, Nepal, China, Brazil, Norway, and Italy were incorporated, as well as updated claims data from the USA and new claims data from Taiwan (province of China) and Singapore. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between rates of incidence, prevalence, remission, and cause of death for each condition. YLDs were estimated as the product of a prevalence estimate and a disability weight for health states of each mutually exclusive sequela, adjusted for comorbidity. We updated the Socio-demographic Index (SDI), a summary development indicator of income per capita, years of schooling, and total fertility rate. Additionally, we calculated differences between male and female YLDs to identify divergent trends across sexes. GBD 2017 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting.

FINDINGS

Globally, for females, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and haemoglobinopathies and haemolytic anaemias in both 1990 and 2017. For males, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and tuberculosis including latent tuberculosis infection in both 1990 and 2017. In terms of YLDs, low back pain, headache disorders, and dietary iron deficiency were the leading Level 3 causes of YLD counts in 1990, whereas low back pain, headache disorders, and depressive disorders were the leading causes in 2017 for both sexes combined. All-cause age-standardised YLD rates decreased by 3·9% (95% uncertainty interval [UI] 3·1-4·6) from 1990 to 2017; however, the all-age YLD rate increased by 7·2% (6·0-8·4) while the total sum of global YLDs increased from 562 million (421-723) to 853 million (642-1100). The increases for males and females were similar, with increases in all-age YLD rates of 7·9% (6·6-9·2) for males and 6·5% (5·4-7·7) for females. We found significant differences between males and females in terms of age-standardised prevalence estimates for multiple causes. The causes with the greatest relative differences between sexes in 2017 included substance use disorders (3018 cases [95% UI 2782-3252] per 100 000 in males vs s1400 [1279-1524] per 100 000 in females), transport injuries (3322 [3082-3583] vs 2336 [2154-2535]), and self-harm and interpersonal violence (3265 [2943-3630] vs 5643 [5057-6302]).

INTERPRETATION

Global all-cause age-standardised YLD rates have improved only slightly over a period spanning nearly three decades. However, the magnitude of the non-fatal disease burden has expanded globally, with increasing numbers of people who have a wide spectrum of conditions. A subset of conditions has remained globally pervasive since 1990, whereas other conditions have displayed more dynamic trends, with different ages, sexes, and geographies across the globe experiencing varying burdens and trends of health loss. This study emphasises how global improvements in premature mortality for select conditions have led to older populations with complex and potentially expensive diseases, yet also highlights global achievements in certain domains of disease and injury.

FUNDING

Bill & Melinda Gates Foundation.

Population and fertility by age and sex for 195 countries and territories, 1950-2017: a systematic analysis for the Global Burden of Disease Study 2017

BACKGROUND

Population estimates underpin demographic and epidemiological research and are used to track progress on numerous international indicators of health and development. To date, internationally available estimates of population and fertility, although useful, have not been produced with transparent and replicable methods and do not use standardised estimates of mortality. We present single-calendar year and single-year of age estimates of fertility and population by sex with standardised and replicable methods.

METHODS

We estimated population in 195 locations by single year of age and single calendar year from 1950 to 2017 with standardised and replicable methods. We based the estimates on the demographic balancing equation, with inputs of fertility, mortality, population, and migration data. Fertility data came from 7817 location-years of vital registration data, 429 surveys reporting complete birth histories, and 977 surveys and censuses reporting summary birth histories. We estimated age-specific fertility rates (ASFRs; the annual number of livebirths to women of a specified age group per 1000 women in that age group) by use of spatiotemporal Gaussian process regression and used the ASFRs to estimate total fertility rates (TFRs; the average number of children a woman would bear if she survived through the end of the reproductive age span [age 10-54 years] and experienced at each age a particular set of ASFRs observed in the year of interest). Because of sparse data, fertility at ages 10-14 years and 50-54 years was estimated from data on fertility in women aged 15-19 years and 45-49 years, through use of linear regression. Age-specific mortality data came from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 estimates. Data on population came from 1257 censuses and 761 population registry location-years and were adjusted for underenumeration and age misreporting with standard demographic methods. Migration was estimated with the GBD Bayesian demographic balancing model, after incorporating information about refugee migration into the model prior. Final population estimates used the cohort-component method of population projection, with inputs of fertility, mortality, and migration data. Population uncertainty was estimated by use of out-of-sample predictive validity testing. With these data, we estimated the trends in population by age and sex and in fertility by age between 1950 and 2017 in 195 countries and territories.

FINDINGS

From 1950 to 2017, TFRs decreased by 49·4% (95% uncertainty interval [UI] 46·4-52·0). The TFR decreased from 4·7 livebirths (4·5-4·9) to 2·4 livebirths (2·2-2·5), and the ASFR of mothers aged 10-19 years decreased from 37 livebirths (34-40) to 22 livebirths (19-24) per 1000 women. Despite reductions in the TFR, the global population has been increasing by an average of 83·8 million people per year since 1985. The global population increased by 197·2% (193·3-200·8) since 1950, from 2·6 billion (2·5-2·6) to 7·6 billion (7·4-7·9) people in 2017; much of this increase was in the proportion of the global population in south Asia and sub-Saharan Africa. The global annual rate of population growth increased between 1950 and 1964, when it peaked at 2·0%; this rate then remained nearly constant until 1970 and then decreased to 1·1% in 2017. Population growth rates in the southeast Asia, east Asia, and Oceania GBD super-region decreased from 2·5% in 1963 to 0·7% in 2017, whereas in sub-Saharan Africa, population growth rates were almost at the highest reported levels ever in 2017, when they were at 2·7%. The global average age increased from 26·6 years in 1950 to 32·1 years in 2017, and the proportion of the population that is of working age (age 15-64 years) increased from 59·9% to 65·3%. At the national level, the TFR decreased in all countries and territories between 1950 and 2017; in 2017, TFRs ranged from a low of 1·0 livebirths (95% UI 0·9-1·2) in Cyprus to a high of 7·1 livebirths (6·8-7·4) in Niger. The TFR under age 25 years (TFU25; number of livebirths expected by age 25 years for a hypothetical woman who survived the age group and was exposed to current ASFRs) in 2017 ranged from 0·08 livebirths (0·07-0·09) in South Korea to 2·4 livebirths (2·2-2·6) in Niger, and the TFR over age 30 years (TFO30; number of livebirths expected for a hypothetical woman ageing from 30 to 54 years who survived the age group and was exposed to current ASFRs) ranged from a low of 0·3 livebirths (0·3-0·4) in Puerto Rico to a high of 3·1 livebirths (3·0-3·2) in Niger. TFO30 was higher than TFU25 in 145 countries and territories in 2017. 33 countries had a negative population growth rate from 2010 to 2017, most of which were located in central, eastern, and western Europe, whereas population growth rates of more than 2·0% were seen in 33 of 46 countries in sub-Saharan Africa. In 2017, less than 65% of the national population was of working age in 12 of 34 high-income countries, and less than 50% of the national population was of working age in Mali, Chad, and Niger.

INTERPRETATION

Population trends create demographic dividends and headwinds (ie, economic benefits and detriments) that affect national economies and determine national planning needs. Although TFRs are decreasing, the global population continues to grow as mortality declines, with diverse patterns at the national level and across age groups. To our knowledge, this is the first study to provide transparent and replicable estimates of population and fertility, which can be used to inform decision making and to monitor progress.

FUNDING

Bill & Melinda Gates Foundation.

Particulate matter and markers of glycemic control and insulin resistance in type 2 diabetic patients: result from Wellcome Trust Genetic study

There is growing evidence that air pollution is associated with increased risk of type 2 diabetes (T2DM). However, information related to whether particulate matter (PM) contributing to worsened metabolic control in T2DM patients is inconsistent. We examined the association of PM₁₀ exposure with glucose-function parameters in young-onset T2DM patients. We investigated the association between a year ambient concentration of PM₁₀ at residential places, using AERMOD dispersion model, with fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), 2 h post meal plasma glucose (2hPG), homeostasis model assessment of insulin resistance (HOMA-IR), β-cell function (HOMA-β) and disposition index (DI) in 1213 diabetic patients from the Wellcome Trust Genetic study at the Diabetes Unit, KEM Hospital Research Center, Pune, India. We used linear regression models and adjusted for a variety of individual and environmental confounding variables. Possible effect modification by age, gender, waist-to-hip ratio (WHR) and smoking status were investigated. Sensitivity analysis assessed the impact of relative humidity (RH) and temperature a day before examination and anti-diabetic and HHR medication (Hydralazine, Hydrochlorothiazide and Reserpine). We found that 1 SD increment in background concentration of PM₁₀ at residential places (43.83 µg/m³) was significantly associated with 2.25 mmol/mol and 0.38 mmol/l increase in arithmetic means of HbA1c and 2hPG, respectively. A similar increase in PM₁₀ was also associated with 4.89% increase in geometric mean of HOMA-IR. The associations remained significant after adjustment to RH and temperature, and WHR and smoking enhanced the size of the effect. Our study suggests that long-term exposure to PM₁₀ is associated with higher glycaemia and insulin resistance. In context of our previous demonstration of association of SO₂ and NO _x and plasma C-reactive protein, we suggest that air pollution could influence progression of diabetes complications. Prospective studies and interventions are required to define mechanism and confirm causality.

Prevalence, risk factors and clinical correlates of COPD in a rural setting in Tanzania

Chronic obstructive pulmonary disease (COPD) causes substantial burden of disease in developed countries, but there are limited data from Africa. We aimed to estimate the prevalence of COPD in Tanzania and identify the risk factors associated with it.This was a cross-sectional descriptive survey involving adults aged ≥35 years. We collected data on symptoms and risk factors using the Burden of Obstructive Lung Diseases questionnaire. Spirometry was performed and COPD diagnosed based on post-bronchodilator forced expiratory volume in 1 s/forced vital capacity <70%. We also measured indoor and outdoor carbon monoxide (CO) levels.A total of 869 participants (49.1% females) completed the questionnaires. Of these, 57.1% completed post-bronchodilator spirometry. Of the 25.2% ever-smokers, only 5.4% were current smokers. COPD prevalence was estimated at 17.5% (21.7% in males and 12.9% in females). COPD was associated with a history of cough, phlegm production and wheezing. 51.7% of COPD patients reported cough and 85% had mild to moderate airway limitation. Females had a higher rate of exacerbation. Pulmonary tuberculosis (TB) was reported in 10% of patients. Only 1.7% of patients who were diagnosed as COPD had ever received any medication, with only one female COPD patient having received an inhaler. 99.5% of the population used biomass fuels for cooking. The majority of households had CO levels up to 20 ppm.The prevalence of COPD in Tanzania is high, with a peak at a relatively young age and a preponderance in males. A history of TB, cigarette smoking and male sex are important risk factors. Indoor air pollution coupled with use of biomass fuel for cooking and heating may be an important risk factor for developing COPD in rural Tanzania. However, these factors need to be studied further.

Global, regional, and national incidence, prevalence, and years lived with disability for 328 diseases and injuries for 195 countries, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016

BACKGROUND

As mortality rates decline, life expectancy increases, and populations age, non-fatal outcomes of diseases and injuries are becoming a larger component of the global burden of disease. The Global Burden of Diseases, Injuries, and Risk Factors Study 2016 (GBD 2016) provides a comprehensive assessment of prevalence, incidence, and years lived with disability (YLDs) for 328 causes in 195 countries and territories from 1990 to 2016.

METHODS

We estimated prevalence and incidence for 328 diseases and injuries and 2982 sequelae, their non-fatal consequences. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between incidence, prevalence, remission, and cause of death rates for each condition. For some causes, we used alternative modelling strategies if incidence or prevalence needed to be derived from other data. YLDs were estimated as the product of prevalence and a disability weight for all mutually exclusive sequelae, corrected for comorbidity and aggregated to cause level. We updated the Socio-demographic Index (SDI), a summary indicator of income per capita, years of schooling, and total fertility rate. GBD 2016 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER).

FINDINGS

Globally, low back pain, migraine, age-related and other hearing loss, iron-deficiency anaemia, and major depressive disorder were the five leading causes of YLDs in 2016, contributing 57·6 million (95% uncertainty interval [UI] 40·8-75·9 million [7·2%, 6·0-8·3]), 45·1 million (29·0-62·8 million [5·6%, 4·0-7·2]), 36·3 million (25·3-50·9 million [4·5%, 3·8-5·3]), 34·7 million (23·0-49·6 million [4·3%, 3·5-5·2]), and 34·1 million (23·5-46·0 million [4·2%, 3·2-5·3]) of total YLDs, respectively. Age-standardised rates of YLDs for all causes combined decreased between 1990 and 2016 by 2·7% (95% UI 2·3-3·1). Despite mostly stagnant age-standardised rates, the absolute number of YLDs from non-communicable diseases has been growing rapidly across all SDI quintiles, partly because of population growth, but also the ageing of populations. The largest absolute increases in total numbers of YLDs globally were between the ages of 40 and 69 years. Age-standardised YLD rates for all conditions combined were 10·4% (95% UI 9·0-11·8) higher in women than in men. Iron-deficiency anaemia, migraine, Alzheimer's disease and other dementias, major depressive disorder, anxiety, and all musculoskeletal disorders apart from gout were the main conditions contributing to higher YLD rates in women. Men had higher age-standardised rates of substance use disorders, diabetes, cardiovascular diseases, cancers, and all injuries apart from sexual violence. Globally, we noted much less geographical variation in disability than has been documented for premature mortality. In 2016, there was a less than two times difference in age-standardised YLD rates for all causes between the location with the lowest rate (China, 9201 YLDs per 100 000, 95% UI 6862-11943) and highest rate (Yemen, 14 774 YLDs per 100 000, 11 018-19 228).

INTERPRETATION

The decrease in death rates since 1990 for most causes has not been matched by a similar decline in age-standardised YLD rates. For many large causes, YLD rates have either been stagnant or have increased for some causes, such as diabetes. As populations are ageing, and the prevalence of disabling disease generally increases steeply with age, health systems will face increasing demand for services that are generally costlier than the interventions that have led to declines in mortality in childhood or for the major causes of mortality in adults. Up-to-date information about the trends of disease and how this varies between countries is essential to plan for an adequate health-system response.

FUNDING

Bill & Melinda Gates Foundation, and the National Institute on Aging and the National Institute of Mental Health of the National Institutes of Health.

Global, regional, and national under-5 mortality, adult mortality, age-specific mortality, and life expectancy, 1970-2016: a systematic analysis for the Global Burden of Disease Study 2016

BACKGROUND

Detailed assessments of mortality patterns, particularly age-specific mortality, represent a crucial input that enables health systems to target interventions to specific populations. Understanding how all-cause mortality has changed with respect to development status can identify exemplars for best practice. To accomplish this, the Global Burden of Diseases, Injuries, and Risk Factors Study 2016 (GBD 2016) estimated age-specific and sex-specific all-cause mortality between 1970 and 2016 for 195 countries and territories and at the subnational level for the five countries with a population greater than 200 million in 2016.

METHODS

We have evaluated how well civil registration systems captured deaths using a set of demographic methods called death distribution methods for adults and from consideration of survey and census data for children younger than 5 years. We generated an overall assessment of completeness of registration of deaths by dividing registered deaths in each location-year by our estimate of all-age deaths generated from our overall estimation process. For 163 locations, including subnational units in countries with a population greater than 200 million with complete vital registration (VR) systems, our estimates were largely driven by the observed data, with corrections for small fluctuations in numbers and estimation for recent years where there were lags in data reporting (lags were variable by location, generally between 1 year and 6 years). For other locations, we took advantage of different data sources available to measure under-5 mortality rates (U5MR) using complete birth histories, summary birth histories, and incomplete VR with adjustments; we measured adult mortality rate (the probability of death in individuals aged 15-60 years) using adjusted incomplete VR, sibling histories, and household death recall. We used the U5MR and adult mortality rate, together with crude death rate due to HIV in the GBD model life table system, to estimate age-specific and sex-specific death rates for each location-year. Using various international databases, we identified fatal discontinuities, which we defined as increases in the death rate of more than one death per million, resulting from conflict and terrorism, natural disasters, major transport or technological accidents, and a subset of epidemic infectious diseases; these were added to estimates in the relevant years. In 47 countries with an identified peak adult prevalence for HIV/AIDS of more than 0·5% and where VR systems were less than 65% complete, we informed our estimates of age-sex-specific mortality using the Estimation and Projection Package (EPP)-Spectrum model fitted to national HIV/AIDS prevalence surveys and antenatal clinic serosurveillance systems. We estimated stillbirths, early neonatal, late neonatal, and childhood mortality using both survey and VR data in spatiotemporal Gaussian process regression models. We estimated abridged life tables for all location-years using age-specific death rates. We grouped locations into development quintiles based on the Socio-demographic Index (SDI) and analysed mortality trends by quintile. Using spline regression, we estimated the expected mortality rate for each age-sex group as a function of SDI. We identified countries with higher life expectancy than expected by comparing observed life expectancy to anticipated life expectancy on the basis of development status alone.

FINDINGS

Completeness in the registration of deaths increased from 28% in 1970 to a peak of 45% in 2013; completeness was lower after 2013 because of lags in reporting. Total deaths in children younger than 5 years decreased from 1970 to 2016, and slower decreases occurred at ages 5-24 years. By contrast, numbers of adult deaths increased in each 5-year age bracket above the age of 25 years. The distribution of annualised rates of change in age-specific mortality rate differed over the period 2000 to 2016 compared with earlier decades: increasing annualised rates of change were less frequent, although rising annualised rates of change still occurred in some locations, particularly for adolescent and younger adult age groups. Rates of stillbirths and under-5 mortality both decreased globally from 1970. Evidence for global convergence of death rates was mixed; although the absolute difference between age-standardised death rates narrowed between countries at the lowest and highest levels of SDI, the ratio of these death rates-a measure of relative inequality-increased slightly. There was a strong shift between 1970 and 2016 toward higher life expectancy, most noticeably at higher levels of SDI. Among countries with populations greater than 1 million in 2016, life expectancy at birth was highest for women in Japan, at 86·9 years (95% UI 86·7-87·2), and for men in Singapore, at 81·3 years (78·8-83·7) in 2016. Male life expectancy was generally lower than female life expectancy between 1970 and 2016, and the gap between male and female life expectancy increased with progression to higher levels of SDI. Some countries with exceptional health performance in 1990 in terms of the difference in observed to expected life expectancy at birth had slower progress on the same measure in 2016.

INTERPRETATION

Globally, mortality rates have decreased across all age groups over the past five decades, with the largest improvements occurring among children younger than 5 years. However, at the national level, considerable heterogeneity remains in terms of both level and rate of changes in age-specific mortality; increases in mortality for certain age groups occurred in some locations. We found evidence that the absolute gap between countries in age-specific death rates has declined, although the relative gap for some age-sex groups increased. Countries that now lead in terms of having higher observed life expectancy than that expected on the basis of development alone, or locations that have either increased this advantage or rapidly decreased the deficit from expected levels, could provide insight into the means to accelerate progress in nations where progress has stalled.

FUNDING

Bill & Melinda Gates Foundation, and the National Institute on Aging and the National Institute of Mental Health of the National Institutes of Health.

Air pollution and respiratory health among diabetic and non-diabetic subjects in Pune, India-results from the Wellcome Trust Genetic Study

Diabetics may be more vulnerable to the harmful effects of ambient air pollutants than healthy individuals. But, the risk factors that lead to susceptibility to air pollution in diabetics have not yet been identified. We examined the effect of exposure to ambient PM₁₀ on chronic symptoms and the pulmonary function tests (PFT) in diabetic and non-diabetic subjects. Also, to investigate possible determinants of susceptibility, we recruited 400 type 2 diabetic and 465 healthy subjects who were investigated for chronic respiratory symptoms (CRSs) and then underwent measurement of forced vital capacity (FVC) and forced expiratory volume 1 (FEV1) according to standard protocol. Percent predicted FEV1 and FVC (FEV1% and FVC%, respectively) for each subject were calculated. Particulate matter (PM₁₀) concentrations at residence place of subjects were estimated using AERMOD dispersion model. The association between PM₁₀ and CRSs was explored using logistic regression. We also used linear regression models controlling for potential confounders to study the association between chronic exposure to PM₁₀ and FEV1% and FVC%. Prevalence of current wheezing, allergy symptom, chest tightness, FEV1/FVC <70%, and physician-diagnosed asthma and COPD was significantly higher among diabetic subjects than non-diabetics. There was no significant difference between percent predicted value of PFT among diabetic and non-diabetic subjects (P < 0.05). We estimated that 1 SD increase in PM₁₀ concentration was associated with a greater risk of having dyspnea by 1.50-fold (95% CI, 1.12-2.01). Higher exposure to PM₁₀ concentration was also significantly associated with lower FVC%. The size of effect for 1 SD μg/m³ (=98.38) increase in PM₁₀ concentration was 3.71% (95% CI, 0.48-4.99) decrease in FVC%. In addition, we indicated that strength of these associations was higher in overweight, smoker, and aged persons. We demonstrated a possible contribution of air pollution to reduced lung function independent of diabetes status. This study suggests that decline in exposure may significantly reduce disease manifestation as dyspnea and impaired lung function. We conduct that higher BMI, smoking, and older age were associated with higher levels of air pollution effects.

Challenges in recruitment and retention of clinical trial subjects

BACKGROUND

Successful recruitment of patients is known to be one of the most challenging aspects in conduct of randomized controlled trials. Inadequate patient retention during conduct of trial affects conclusive results.

OBJECTIVE

To assess the level of challenges faced by Indian investigators in recruitment and retention of trial subjects.

METHODS

We developed a survey questionnaire on challenges encountered by investigators in subject recruitment and retention which was hosted on a web portal.

RESULTS

Seventy-three investigators from India participated in the survey. The frequently encountered challenges in subject recruitment were complexity of study protocol (38%), lack of awareness about clinical trials in patients (37%), and sociocultural issues related to trial participation (37%). About 63% of participants strongly agreed that creating a positive awareness about clinical trials among people through press and media, having a dedicated clinical research coordinator for trial (50.7%), and designing a recruitment strategy prior to study initiation (46.6%) would enhance recruitment. Almost 50.7% of participants agreed that interacting with medical community in vicinity of the study site and educating patients about clinical trials during routine outpatient department visits (46.6%) would enhance recruitment. Experiencing a serious adverse event, subject's fear for study procedures (47%) and side effects (44%) were thought to have a moderate effect on subject retention.

CONCLUSION

Our survey has put forth factors related to negative publicity by media, lack of patient education about clinical trials; complex study designs are barriers to clinical trial recruitment in India. It is essential to devise innovative and effective strategies focusing on education of public and mass media about clinical research in India.

Enhancing indoor air quality -The air filter advantage

Air pollution has become the world's single biggest environmental health risk, linked to around 7 million deaths in 2012 according to a recent World Health Organisation (WHO) report. The new data further reveals a stronger link between, indoor and outdoor air pollution exposure and cardiovascular diseases, such as strokes and ischemic heart disease, as well as between air pollution and cancer. The role of air pollution in the development of respiratory diseases, including acute respiratory infections and chronic obstructive pulmonary diseases, is well known. While both indoor and outdoor pollution affect health, recent statistics on the impact of household indoor pollutants (HAP) is alarming. The WHO factsheet on HAP and health states that 3.8 million premature deaths annually - including stroke, ischemic heart disease, chronic obstructive pulmonary disease (COPD) and lung cancer are attributed to exposure to household air pollution. Use of air cleaners and filters are one of the suggested strategies to improve indoor air quality. This review discusses the impact of air pollutants with special focus on indoor air pollutants and the benefits of air filters in improving indoor air quality.

Infection control in the pulmonary function test laboratory

Pulmonary function testing plays a crucial role in the diagnostic evaluation of patients with lung diseases. Cases of cross infection acquired from the pulmonary function laboratory, although rare, have been reported from various countries. It is therefore imperative to identify the risks and potential organisms implicated in cross infections in a pulmonary function test (PFT) laboratory and implement better and more effective infection control procedures, which will help in preventing cross infections. The infrastructure, the daily patient flow, and the prevalent disinfection techniques used in a PFT laboratory, all play a significant role in transmission of infections. Simple measures to tackle the cross infection potential in a PFT laboratory can help reduce this risk to a bare minimum. Use of specialized techniques and equipment can also be of much use in a set up that has a high turnover of patients. This review aims at creating awareness about the possible pathogens and situations commonly encountered in a PFT laboratory. We have attempted to suggest some relevant and useful infection control measures with regard to disinfection, sterilization, and patient planning and segregation to help minimize the risk of cross infections in a PFT laboratory. The review also highlights the lacuna in the current scenario of PFT laboratories in India and the need to develop newer and better methods of infection control, which will be more user-friendly and cost effective. Further studies to study the possible pathogens in a PFT laboratory and evaluate the prevalent infection control strategies will be needed to enable us to draw more precious conclusions, which can lead to more relevant, contextual recommendations for cross infections control in PFT lab in India.

Physical properties of intact proteins may predict allergenicity or lack thereof

Background

Predicting the allergenicity of proteins is challenging. We considered the possibility that the properties of the intact protein that may alter the likelihood of being taken up by antigen presenting cells, may be useful adjuncts in predicting allergens and non-allergens in silico. It has been shown that negatively charged acidic proteins are preferentially processed by dendritic cells.

Methodology

Datasets (aeroallergen, food-allergen and non-allergen) for in-silico study were obtained from public databases. Isoelectric point (pI), net charge, and electrostatic potential (EP) were calculated from the protein sequence (for pI and net charge) or predicted structure (for EP).

Result

Allergens and non allergens differed significantly in pI, net charge, and EP (p<0.0001). Cluster analysis based on these parameters resulted in well defined clusters. Non-allergens were characterized by neutral to basic pI (mean±SE, 7.6±0.16) and positive charge. In contrast allergens were acidic (5.7±0.15) and negatively charged. Surface electrostatic potentials calculated from predicted structures were mostly negative for allergens and mostly positive for non-allergens. The classification accuracy for non-allergens was superior to that for allergens. Thus neutral to basic pI, positive charge, and positive electrostatic potentials characterize non-allergens, and seem rare in allergens (p<0.0001). It may be possible to predict reduced likelihood of allergenicity in such proteins, but this needs to be prospectively validated.

Tiotropium administered by a pressurized metered dose inhaler (pMDI) and spacer produces a similar bronchodilator response as that administered by a Rotahaler® in adult subjects with stable moderate-to-severe COPD

BACKGROUND

Tiotropium is a new long-acting anticholinergic bronchodilator, which is recommended as first-line therapy in the management of chronic obstructive pulmonary disease (COPD). It is currently available in the form of a dry powder inhaler worldwide. Some COPD patients find it difficult to generate inspiratory flow rates of up to 40 l/min, which is required for the drug to reach the airways. To overcome this, a new pMDI form has been developed for administration of tiotropium in patients with COPD. The clinical efficacy of this mode of tiotropium delivery has, so far, not been compared with the currently available dry powder inhaler (DPI) devices.

AIMS AND OBJECTIVES

To compare the bronchodilator effects of a single dose of 18 mcg of tiotropium administered via a pressurized meter dose inhaler (pMDI) and spacer with the currently available DPI form through Rotahaler.

STUDY DESIGN

A randomized, double-blind, double-dummy, three-period, placebo-controlled, crossover, single-center study was conducted in 19 patients with stable COPD. Single doses of tiotropium (18 mcg) or placebo were administered on three separate study days (4-7 days apart) through a Rotahaler and pMDI with a non-static spacer (Zerostat, Cipla Ltd.). During each study visit forced expiratory volume in 1s (FEV(1)) and forced vital capacity (FVC) were measured over a period of 24 h at 11 different time points (0, 15, 30 min, 1, 2, 3, 4, 6, 8, 12 and 24h), using a bellows spirometer (Vitalograph) 2160, UK) while static parameters like inspiratory capacity (IC), residual volume (RV), intrathoracic gas volume (ITGV) and total lung capacity (TLC) were measured by bodyplethysmography (Jaeger Masterscreen, Germany) at 0 min, 3, 8 and 24 h.

RESULTS

Tiotropium administered through both pMDI (and spacer) and DPI showed significantly better mean FEV(1) and mean FVC differences from baseline, in terms of mean maximum change and area under curve over a period of 24 h (AUC(0-24 h)), as compared to placebo. The mean IC and trough FEV(1) values also improved significantly with tiotropium administered through both the devices as compared to placebo. For all these parameters, there was no difference in the efficacy between pMDI and DPI. There was also no significant difference between the time to onset, time to maximum response and duration of response between tiotropium administered through both the study devices. On the other hand, there was no significant difference in RV, ITGV and TLC by a single dose of tiotopium delivered through either of the devices when compared with placebo over a period of 24 h.

CONCLUSION

This is the first study to demonstrate that tiotropium administered by pMDI and spacer shows a superior time-dependent bronchodilator response when compared to placebo, and that this therapeutic efficacy is similar to tiotropium administered by DPI. We recommend the use of tiotropium administered through a pMDI and spacer to those COPD patients who prefer to use the pMDI device, and especially in those who cannot generate sufficient inspiratory flows required for dry powder inhaler devices.

Different airway inflammatory responses in asthmatic and healthy humans exposed to diesel

Particulate matter (PM) pollution adversely affects the airways, with asthmatic subjects thought to be especially sensitive. The authors hypothesised that exposure to diesel exhaust (DE), a major source of PM, would induce airway neutrophilia in healthy subjects, and that either these responses would be exaggerated in subjects with mild allergic asthma, or DE would exacerbate pre-existent allergic airways. Healthy and mild asthmatic subjects were exposed for 2 h to ambient levels of DE (particles with a 50% cut-off aerodynamic diameter of 10 microm (PM10) 108 microg x m(-3)) and lung function and airway inflammation were assessed. Both groups showed an increase in airway resistance of similar magnitude after DE exposure. Healthy subjects developed airway inflammation 6 h after DE exposure, with airways neutrophilia and lymphocytosis together with an increase in interleukin-8 (IL-8) protein in lavage fluid, increased IL-8 messenger ribonucleic acid expression in the bronchial mucosa and upregulation of the endothelial adhesion molecules. In asthmatic subjects, DE exposure did not induce a neutrophilic response or exacerbate their pre-existing eosinophilic airway inflammation. Epithelial staining for the cytokine IL-10 was increased after DE in the asthmatic group. Differential effects on the airways of healthy subjects and asthmatics of particles with a 50% cut-off aerodynamic diameter of 10 microm at concentrations below current World Health Organisation air quality standards have been observed in this study. Further work is required to elucidate the significance of these differential responses.

The anti-inflammatory effects of leukotriene-modifying drugs and their use in asthma

Asthma is a chronic inflammatory disease of the airways. Anti-inflammatory drug therapy, primarily using corticosteroids, is now considered the first-line treatment in the management of all grades of asthma severity. Although corticosteroids are believed to be the most potent anti-inflammatory agents available, they do not suppress all inflammatory mediators involved in the asthmatic response. Leukotrienes, which are lipid mediators generated from the metabolism of arachidonic acid, play an important role in the pathogenesis of asthma. They produce bronchospasm, increase bronchial hyperresponsiveness, mucus production, and mucosal edema, and enhance airway smooth muscle cell proliferation and eosinophil recruitment into the airways, and their synthesis or release is unaffected by corticosteroid administration. The use of leukotriene synthesis inhibitors or leukotriene receptor antagonists as anti-inflammatory therapies in asthma has therefore been investigated. Beneficial effects of leukotriene-modifying drugs have been demonstrated in the management of all grades of asthma severity, and there is evidence that certain patient groups (such as those with exercise-induced asthma or aspirin-induced asthma) may be particularly suitable for such therapy.

Aspirin and asthma

Aspirin is not only one of the best-documented medicines in the world, but also one of the most frequently used drugs of all times. In addition to its role as an analgesic, aspirin is being increasingly used in the prophylaxis of ischemic heart disease and strokes. The prevalence of aspirin intolerance is around 5 to 6%. Up to 20% of the asthmatic population is sensitive to aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) and present with a triad of rhinitis, sinusitis, and asthma when exposed to the offending drugs. This syndrome is referred to as aspirin-induced asthma (AIA). The pathogenesis of AIA has implicated both the lipoxygenase (LO) and the cyclooxygenase (COX) pathways. By inhibiting the COX pathway, aspirin diverts arachidonic acid metabolites to the LO pathway. This also leads to a decrease in the levels of prostaglandin (PG) E(2), the anti-inflammatory PG, along with an increase in the synthesis of cysteinyl leukotrienes (LTs). Evidence suggests that patients with AIA have increased activity of LTC(4) synthase, the rate-limiting enzyme in the cysteinyl LT synthesis, in their bronchial biopsy specimens, thereby tilting the balance in favor of inflammation. LT-modifying drugs are effective in blocking the bronchoconstriction provoked by aspirin and are used in the treatment of this condition. Aspirin desensitization has a role in the management of AIA, especially in patients who need prophylaxis from thromboembolic diseases, myocardial infarction, and stroke. This review covers the latest understanding of pathogenesis, clinical features, and management of AIA.

Acute exposure to diesel exhaust increases IL-8 and GRO-alpha production in healthy human airways

We have previously demonstrated that short-term exposure to diesel exhaust (DE) for 1 h induced a marked leukocytic infiltration in the airways of healthy human volunteers involving neutrophils, lymphocytes, and mast cells along with increases in several inflammatory mediators. We hypothesized that the leukocyte infiltration and the various inflammatory responses induced by DE were mediated by enhanced chemokine and cytokine production by resident cells of the airway tissue and lumen. To investigate this, 15 healthy human volunteers were exposed to diluted DE and air on two separate occasions for 1 h each in an exposure chamber. Fiberoptic bronchoscopy was performed 6 h after each exposure to obtain endobronchial biopsies and bronchial wash (BW) cells. Using reverse transcriptase/polymerase chain reaction enzyme-linked immunosorbent assay (RT-PCR ELISA), a novel and sensitive technique to quantify relative amounts of cytokine mRNA gene transcripts, and immunohistochemical staining with computer-assisted image analysis to quantify expression of cytokine protein in the bronchial tissue, we have demonstrated that DE enhanced gene transcription of interleukin-8 (IL-8) in the bronchial tissue and BW cells along with increases in IL-8 and growth-regulated oncogene-alpha (GRO-alpha) protein expression in the bronchial epithelium, and an accompanying trend toward an increase in IL-5 mRNA gene transcripts in the bronchial tissue. There were no significant changes in the gene transcript levels of interleukin-1B (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), interferon gamma (IFN-gamma), and granulocyte macrophage colony-stimulating factor (GM-CSF) either in the bronchial tissue or BW cells after DE exposure at this time point. These observations suggest an underlying mechanism for DE-induced airway leukocyte infiltration and offer a possible explanation for the association observed between ambient levels of particulate matter and various respiratory health outcome indices noted in epidemiological studies.

Alpha1-adrenergic hypothesis for pulmonary hypertension

Pulmonary hypertension (PH) is a chronic and disabling condition that affects the pulmonary vasculature. Once PH is diagnosed, the prognosis is generally poor with a rapid downhill course. PH management is largely empirical because the underlying pathophysiologic mechanisms that are responsible for the excessive vasoconstrictor and vascular smooth muscle proliferative responses are poorly understood. Based on new information concerning the role of adrenergic receptors in regulating various cellular functions, a new perspective on the genesis of PH has emerged, along with a unifying hypothesis for the role of alpha1-adrenergic receptors present in the pulmonary vasculature as the major contributor to the pathophysiologic changes associated with PH. Adrenergic receptors that are present on vascular smooth muscle cells regulate vascular tone and growth. The alpha1-adrenergic receptors that are present on the small- and medium-sized pulmonary arteries have a unique and greatly enhanced affinity and activity to alpha1-adrenergic agonists. Under physiologic conditions, this helps in regulating vascular tone and maintains an adequate ventilation/perfusion matching. However, the excessive stimulation of alpha1-adrenergic receptors produces not only smooth muscle contraction but also proliferation and growth. The conditions that produce an increase in alpha1-adrenoreceptor gene synthesis, density, and activity (such as hypoxia or changes in vessel wall pressure) or increase the levels of its agonists (such as norepinephrine, appetite suppressants, or cocaine) greatly enhance pulmonary vascular smooth muscle contractile and proliferative responses and lead to the development of PH. An understanding of the role played by these receptors in the pathophysiology of PH would not only help to avoid the use of alpha1-agonists for appetite suppression and other disease states, but also would help in developing new drugs to block these receptors. A further understanding of the alpha1-adrenoreceptor subtypes present in the pulmonary vasculature, the factors that regulate their expression, and their intracellular signaling pathways would help researchers to devise newer therapeutic strategies and, hopefully, to find a cure for this crippling condition.

Study of superior vena cava syndrome--aetiopathology, diagnosis and management

Thirty two patients of superior vena cava syndrome (SVCS) were studied. Clinical features noted were diffuse neck swelling, breathlessness, chest pain, engorged neck veins, facial swelling and dilated engorged veins over chest wall. Radiography revealed a superior mediastinal mass in 31.2% of patients and right upper lobe mass in 50% patients. FNAC of lung showed aetiology in 34.5% patients and lymph node biopsy in 31.2% patients. Aetiology of SVCS was benign in 12.5% patients and malignant in 87.5% patients. Squamous cell carcinoma was the commonest cause of SVSC. Radiotherapy proved to be the most beneficial form of treatment. The mean survival period in patients due to malignant etiology was 6 months.