The impact of primary headaches on disability outcomes: a literature review and meta-analysis to inform future iterations of the Global Burden of Disease study

BACKGROUND

The burden and disability associated with headaches are conceptualized and measured differently at patients' and populations' levels. At the patients' level, through patient-reported outcome measures (PROMs); at population level, through disability weights (DW) and years lived with a disability (YLDs) developed by the Global Burden of Disease Study (GBD). DW are 0-1 coefficients that address health loss and have been defined through lay descriptions. With this literature review, we aimed to provide a comprehensive analysis of disability in headache disorders, and to present a coefficient referring to patients' disability which might inform future GBD definitions of DW for headache disorders.

METHODS

We searched SCOPUS and PubMed for papers published between 2015 and 2023 addressing disability in headache disorders. The selected manuscript included a reference to headache frequency and at least one PROM. A meta-analytic approach was carried out to address relevant differences for the most commonly used PROMs (by headache type, tertiles of medication intake, tertiles of females' percentage in the sample, and age). We developed a 0-1 coefficient based on the MIDAS, on the HIT-6, and on MIDAS + HIT-6 which was intended to promote future DW iterations by the GBD consortium.

RESULTS

A total of 366 studies, 596 sub-samples, and more than 133,000 single patients were available, mostly referred to cases with migraine. Almost all PROMs showed the ability to differentiate disability severity across conditions and tertiles of medication intake. The indexes we developed can be used to inform future iterations of DW, in particular considering their ability to differentiate across age and tertiles of medication intake.

CONCLUSIONS

Our review provides reference values for the most commonly used PROMS and a data-driven coefficient whose main added value is its ability to differentiate across tertiles of age and medication intake which underlie on one side the increased burden due to aging (it is likely connected to the increased impact of common comorbidities), and by the other side the increased burden due to medication consumption, which can be considered as a proxy for headache severity. Both elements should be considered when describing disability of headache disorders at population levels.

The quality of care index for low back pain: a systematic analysis of the global burden of disease study 1990-2017

BACKGROUND

. Low back pain is one of the major causes of morbidity worldwide. Studies on low back pain quality of care are limited. This study aimed to evaluate the quality of care of low back pain worldwide and compare gender, age, and socioeconomic groups.

METHODS

. This study used GBD data from 1990 to 2017 from the Institute for Health Metrics and Evaluation (IHME) website. Extracted data included low back pain incidence, prevalence, disability-adjusted life years (DALYs), and years lived with disability (YLDs). DALYs to prevalence ratio and prevalence to incidence ratio were calculated and used in the principal component analysis (PCA) to make a proxy of the quality-of-care index (QCI). Age groups, genders, and countries with different socioeconomic statuses regarding low back pain care quality from 1990 to 2017 were compared.

RESULTS

The proxy of QCI showed a slight decrease from 36.44 in 1990 to 35.20 in 2017. High- and upper-middle-income countries showed a decrease in the quality of care from 43.17 to 41.57 and from 36.37 to 36.00, respectively, from 1990 to 2017. On the other hand, low and low-middle-income countries improved, from a proxy of QCI of 20.99 to 27.89 and 27.74 to 29.36, respectively.

CONCLUSION

. Despite improvements in the quality of care for low back pain in low and lower-middle-income countries between 1990 and 2017, there is still a large gap between these countries and higher-income countries. Continued steps must be taken to reduce healthcare barriers in these countries.

The increasing significance of disease severity in a burden of disease framework

Recent estimates have reiterated that non-fatal causes of disease, such as low back pain, headaches and depressive disorders, are amongst the leading causes of disability-adjusted life years (DALYs). For these causes, the contribution of years lived with disability (YLD) - put simply, ill-health - is what drives DALYs, not mortality. Being able to monitor trends in YLD closely is particularly relevant for countries that sit high on the socio-demographic spectrum of development, as it contributes more than half of all DALYs. There is a paucity of data on how the population-level occurrence of disease is distributed according to severity, and as such, the majority of global and national efforts in monitoring YLD lack the ability to differentiate changes in severity across time and location. This raises uncertainties in interpreting these findings without triangulation with other relevant data sources. Our commentary aims to bring this issue to the forefront for users of burden of disease estimates, as its impact is often easily overlooked as part of the fundamental process of generating DALY estimates. Moreover, the wider health harms of the COVID-19 pandemic have underlined the likelihood of latent and delayed demand in accessing vital health and care services that will ultimately lead to exacerbated disease severity and health outcomes. This places increased importance on attempts to be able to differentiate by both the occurrence and severity of disease.

Disability, a priority area for health research in South Africa: an analysis of the burden of disease study 2017

PURPOSE

Disabilities are increasing globally, which is attributed to the overall ageing of populations in affluent countries. This trend may differ in low and middle-income countries. This paper assesses the change over time in Years Lived with Disability (YLD) for South Africa and how this compares to regional and global trends.

MATERIALS AND METHODS

This secondary analysis of the Global Burden of Disease Study 2017 dataset describes the observed contribution of YLD to Disability-Adjusted Life Years (DALYs) per 100 000 people over the period 1990-2016, and forecast to 2030 using simple linear prediction. South African trends are compared to global and sub-Saharan African (SSA) trends to highlight the effect of HIV and policy implications.

RESULTS

Globally, the contribution of YLD to DALYs has increased from ±21.7% in 1990 to ±34% by 2016, with high socio-demographic index countries having a higher contribution (49%). HIV, mental health, musculoskeletal, neurological, and sense organ disorders are the five main contributors to YLD in South Africa (54%). Removing the effects of HIV/AIDS and sexually transmitted infections on YLD, South Africa's trend appears similar to the global trend, yet opposite to the SSA trend.

CONCLUSION

Our analysis shows there is a growing burden of disability in South Africa. Differences in trends with the regional and global patterns can be attributed to the high burden of HIV and non-communicable diseases in South Africa. Therefore, strategies are urgently needed to increase integration of disability and rehabilitation services into chronic HIV and non-communicable disease management. This calls for disability screening to identify functional limitations in routine data collection and case management.IMPLICATIONS FOR REHABILITATIONSouth Africa has experienced an increase in disability prevalence over time.This requires strengthening of services such as mental health interventions, physiotherapy, optometry, and audiology, and linking major disease clusters, such as HIV and the NCDs, to rehabilitation services.The greatest contributors towards disability adjusted life years in South Africa are currently mental disorders (13.8%), HIV and sexually transmitted infections (11.8%), musculoskeletal disorders (10.4%), neurological disorders (8.2%), and sense organ diseases (7.5%).Routine data collection and case management needs to include disability screening to identify developing functional limitations.

Disability adjusted life years associated with COVID-19 in Denmark in the first year of the pandemic

Background

Burden of disease studies measure the public health impact of a disease in a society. The aim of this study was to quantify the direct burden of COVID-19 in the first 12 months of the epidemic in Denmark.

Methods

We collected national surveillance data on positive individuals for SARS-CoV-2 with RT-PCR, hospitalization data, and COVID-19 mortality reported in the period between 26^th of February, 2020 to 25^th of February, 2021. We calculated disability adjusted life years (DALYs) based on the European Burden of Disease Network consensus COVID-19 model, which considers mild, severe, critical health states, and premature death. We conducted sensitivity analyses for two different death-registration scenarios, within 30 and 60 days after first positive test, respectively.

Results

We estimated that of the 211,823 individuals who tested positive to SARS-CoV-2 by RT-PCR in the one-year period, 124,163 (59%; 95% uncertainty interval (UI) 112,782–133,857) had at least mild symptoms of disease. The total estimated disease burden was 30,180 DALYs (95% UI 30,126; 30,242), corresponding to 520 DALYs/100,000. The disease burden was higher in the age groups above 70 years of age, particularly in men. Years of life lost (YLL) contributed with more than 99% of total DALYs. The results of the scenario analysis showed that defining COVID-19-related fatalities as deaths registered up to 30 days after the first positive test led to a lower YLL estimate than when using a 60-days window.

Conclusion

COVID-19 led to a substantial public health impact in Denmark in the first full year of the epidemic. Our estimates suggest that it was the the sixth most frequent cause of YLL in Denmark in 2020. This impact will be higher when including the post-acute consequences of COVID-19 and indirect health outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13694-9.

Measuring disability-adjusted life years (DALYs) due to COVID-19 in Scotland, 2020

Background

Disability-adjusted life years (DALYs) combine the impact of morbidity and mortality and can enable comprehensive, and comparable, assessments of direct and indirect health harms due to COVID-19. Our aim was to estimate DALYs directly due to COVID-19 in Scotland, during 2020; and contextualise its population impact relative to other causes of disease and injury.

Methods

National deaths and daily case data were used. Deaths were based on underlying and contributory causes recorded on death certificates. We calculated DALYs based on the COVID-19 consensus model and methods outlined by the European Burden of Disease Network. DALYs were presented as a range, using a sensitivity analysis based on Years of Life Lost estimates using: cause-specific; and COVID-19 related deaths. All COVID-19 estimates were for 2020.

Results

In 2020, estimates of COVID-19 DALYs in Scotland ranged from 96,500 to 108,200. Direct COVID-19 DALYs were substantial enough to be framed as the second leading cause of disease and injury, with only ischaemic heart disease having a larger impact on population health. Mortality contributed 98% of total DALYs.

Conclusions

The direct population health impact of COVID-19 has been very substantial. Despite unprecedented mitigation efforts, COVID-19 developed from a single identified case in early 2020 to a condition with an impact in Scotland second only to ischaemic heart disease. Periodic estimation of DALYs during 2021, and beyond, will provide indications of the impact of DALYs averted due to the national rollout of the vaccination programme and other continued mitigation efforts, although new variants may pose significant challenges.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13690-022-00862-x.

Analysis of the Global Disease Burden of Down Syndrome Using YLDs, YLLs, and DALYs Based on the Global Burden of Disease 2019 Data

PURPOSE

This study aimed to determine Down syndrome (DS) burden using years lived with disability (YLDs), years of life lost (YLLs), disability-adjusted life years (DALYs), and the trends in these parameters.

METHODS

We obtained the annual YLDs, YLLs, DALYs, and age-standardized rates (ASRs) of DS from 2010 to 2019 using the Global Health Data Exchange tool. The estimated annual percentage changes (EAPCs) in ASR were used to quantify and evaluate DS burden trends. Gaussian-process regression and Pearson's correlation coefficient were used to assess the relationship between DS burden and socio-demographic index (SDI).

RESULTS

Global DALYs decreased by 2.68% from 2010 to 2019 but the ASR was stable, which was mostly explained by the stability in the ASR for YLLs. The ASR of YLDs showed an increasing trend (EAPC = 1.07, 95% CI = 0.45 to 1.69). There was notable regional imbalance, with most of the DALYs or ASRs in areas with relatively low SDI. The DALY rates of DS were mostly from the YLLs of children younger than 1 year. Lower SDI areas tended to have higher DS burdens (ρ = -0.3, p < 0.001).

CONCLUSION

This systematic analysis of the global disease burden of DS from 2010 to 2019 revealed that although the global DS DALY and YLL rate is stable, the YLD rate is increasing. And the DS burden varies significantly differences among regions or countries. The present results suggest that future strategies should focus on DS-related deaths in children younger than 1 year and the DS burden in low-SDI regions or countries, since this may be effective in further reducing DS burden.

Estimating the direct Covid-19 disability-adjusted life years impact on the Malta population for the first full year

BACKGROUND

Disability-adjusted life years (DALYs) combine the impact of morbidity and mortality, allowing for comprehensive comparisons of the population. The aim was to estimate the DALYs due to Covid-19 in Malta (March 2020-21) and investigate its impact in relation to other causes of disease at a population level.

METHODS

Mortality and weekly hospital admission data were used to calculate DALYs, based on the European Burden of Disease Network consensus Covid-19 model. Covid-19 infection duration of 14 days was considered. Sensitivity analyses for different morbidity scenarios, including post-acute consequences were presented.

RESULTS

An estimated 70,421 people were infected (with and without symptoms) by Covid-19 in Malta (March 2020-1), out of which 1636 required hospitalisation and 331 deaths, contributing to 5478 DALYs. These DALYs positioned Covid-19 as the fourth leading cause of disease in Malta. Mortality contributed to 95% of DALYs, while post-acute consequences contributed to 60% of morbidity.

CONCLUSIONS

Covid-19 over 1 year has impacted substantially the population health in Malta. Post-acute consequences are the leading morbidity factors that require urgent targeted action to ensure timely multidisciplinary care. It is recommended that DALY estimations in 2021 and beyond are calculated to assess the impact of vaccine roll-out and emergence of new variants.

Recommendations to plan a national burden of disease study

Background

The InfAct (Information for Action) project is a European Commission Joint Action on Health Information which has promoted the potential role of burden of disease (BoD) approaches to improve the current European Union-Health Information System (EU-HIS). It has done so by raising awareness of the concept, the methods used to calculate estimates and their potential implications and uses in policymaking. The BoD approach is a systematic and scientific effort to quantify and compare the magnitude of health loss due to different diseases, injuries, and risk factors with estimates produced by demographic characteristics and geographies for specific points in time. Not all countries have the resources to undertake such work, and may therefore start with a more restricted objective, e.g., a limited number of diseases, or the use of simple measures of population health such as disease prevalence or life expectancy. The main objective to develop these recommendations was to facilitate those countries planning to start a national burden of disease study.

Results

These recommendations could be considered as minimum requirements for those countries planning to start a BoD study and includes following elements: (1) Define the objectives of a burden of disease study within the context of your country, (2) Identify, communicate and secure the benefits of performing national burden of disease studies, (3) Secure access to the minimum required data sources, (4) Ensure the minimum required capacity and capability is available to carry out burden of disease study, (5) Establish a clear governance structure for the burden of disease study and stakeholder engagement/involvement, (6) Choose the appropriate methodological approaches and (7) Knowledge translation. These were guided by the results from our survey performed to identify the needs of European countries for BoD studies, a narrative overview from four European countries (Belgium, Germany, The Netherlands and Scotland) and the summary of a comparative study of country health profiles with national health statistics.

Conclusions

These recommendations as minimum requirements would facilitate efforts by those European countries who intend to perform national BoD studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13690-021-00652-x.

Epidemiological factors for type 2 diabetes mellitus: evidence from the Global Burden of Disease

Background

The United Nations acknowledged diabetes as an epidemic of the 21st century. Global trends demonstrate a continuing growth in its prevalence at approximately 2.5 % per year. The aim of the study was to analyse selected epidemiological factors for type 2 diabetes mellitus in Poland, Central Europe and the World.

Methods

This study presents Global Burden of Disease (GBD) data. Study describes the type 2 diabetes burden in the studied populations based on years lived with disability (YLD), years of life lost (YLL), and disability-adjusted life years (DALYs).

Results

Type 2 diabetes has been demonstrated to be a determinant of reduced life expectancy, as in the analysed period the condition presented an increasing trend, compared to other diseases.

Conclusions

In recent years the observed YLL, YLD and DALY values for type 2 diabetes have been comparable to the expected ones. Thus the prognosis presented by GBD may be used as a reliable source of information and a basis for a health policy that reduces the number of patients with diabetes and related complications, comorbidities or mortality.

Value of a national burden-of-disease study: a comparison of estimates between the Australian Burden of Disease Study 2015 and the Global Burden of Disease Study 2017

BACKGROUND

Estimates of burden of disease are important for monitoring population health, informing policy and service planning. Burden estimates for the same population can be reported differently by national studies [e.g. the Australian Burden of Disease Study (ABDS) and the Global Burden of Disease Study (GBDS)].

METHODS

Australian ABDS 2015 and GBDS 2017 burden estimates and methods for 2015 were compared. Years of Life Lost (YLL), Years Lived with Disability (YLD) and Disability-Adjusted Life Years (DALY) measures were compared for overall burden and 'top 50' causes. Disease-category definitions (based on ICD-10), redistribution algorithms, data sources, disability weights, modelling methods and assumptions were reviewed.

RESULTS

GBDS 2017 estimated higher totals than ABDS 2015 for YLL, YLD and DALY for Australia. YLL differences were mainly driven by differences in the allocation of deaths to disease categories and the redistribution of implausible causes of death. For YLD, the main drivers were data sources, severity distributions and modelling strategies. Most top-50 diseases for DALY had a similar YLL:YLD composition reported.

CONCLUSIONS

Differences in the ABDS and GBDS estimates reflect the different purposes of local and international studies and differences in data and modelling strategies. The GBDS uses all available evidence and is useful for international comparisons. National studies such as the ABDS have the flexibility to meet local needs and often the advantage of access to unpublished data. It is important that all data sources, inputs and models be assessed for quality and appropriateness. As studies evolve, differences should be accounted for through increased transparency of data and methods.

Conducting national burden of disease studies in small countries in Europe- a feasible challenge?

Background

Burden of Disease (BoD) studies use disability-adjusted life years (DALYs) as a population health metric to quantify the years of life lost due to morbidity and premature mortality for diseases, injuries and risk factors occurring in a region or a country. Small countries usually face a number of challenges to conduct epidemiological studies, such as national BoD studies, due to the lack of specific expertise and resources or absence of adequate data. Considering Europe’s small countries of Cyprus, Iceland, Luxembourg, Malta and Montenegro, the aim was to assess whether the various national data sources identified are appropriate to perform national BoD studies.

Main body

The five small countries have a well-established mortality registers following the ICD10 classification, which makes calculation of years of life lost (YLL) feasible. A number of health information data sources were identified in each country, which can provide prevalence data for the calculation of years lived with disability (YLD) for various conditions. These sources include disease-specific registers, hospital discharge data, primary health care data and epidemiological studies, provided by different organisations such as health directorates, institutes of public health, statistical offices and other bodies. Hence, DALYs can be estimated at a national level through the combination of the YLL and YLD information.

On the other hand, small countries face unique challenges such as difficulty to ensure sample representativeness, variations in prevalence estimates especially for rarer diseases, existence of a substantial proportion of non-residents affiliated to healthcare systems and potential exclusion from some European or international initiatives.

Recently established BoD networks may provide a platform for small countries to share experiences, expertise, and engage with countries and institutions that have long-standing experience with BoD assessment.

Conclusion

Apart from mortality registries, adequate health data sources, notably for cancer, are potentially available at the small states to perform national BoD studies. Investing in sharing expert knowledge through engagement of researchers in BoD networks can enable the conduct of country specific BoD studies and the establishment of more accurate DALYs estimates. Such estimates can enable local policymakers to reflect on the relative burden of the different conditions that are contributing to morbidity and mortality at a country level.

Impact of the Burden of COVID-19 in Italy: Results of Disability-Adjusted Life Years (DALYs) and Productivity Loss

The WHO declared the novel coronavirus disease a pandemic, with severe consequences for health and global economic activity and Italy is one of the hardest hit countries. This study aims to assess the socio-economic burden of COVID-19 pandemic in Italy through the estimation of Disability-Adjusted Life Years (DALYs) and productivity loss. The observational study was based on data from official governmental sources collected since the inception of epidemic until 28 April 2020. DALYs for a disease combines the years of life lost due to premature mortality in the population and the years lost due to disability of the disease. In addition to DALYs, temporary productivity loss due to absenteeism from work and permanent productivity loss due to premature mortality were estimated using the Human Capital Approach. The total DALYs amount to 2.01 per 1000 persons. The total permanent productivity loss was around EUR 300 million while the temporary productivity loss was around EUR 100 million. This evaluation does not consider other economic aspects related to lockdown, quarantine of contacts, healthcare direct costs etc. The burden of disease methodology is functional metric for steering choices of health policy and allowing the government to be accountable for the utilization of resources.

Population vulnerability to COVID-19 in Europe: a burden of disease analysis

BACKGROUND

Evidence has emerged showing that elderly people and those with pre-existing chronic health conditions may be at higher risk of developing severe health consequences from COVID-19. In Europe, this is of particular relevance with ageing populations living with non-communicable diseases, multi-morbidity and frailty. Published estimates of Years Lived with Disability (YLD) from the Global Burden of Disease (GBD) study help to characterise the extent of these effects. Our aim was to identify the countries across Europe that have populations at highest risk from COVID-19 by using estimates of population age structure and YLD for health conditions linked to severe illness from COVID-19.

METHODS

Population and YLD estimates from GBD 2017 were extracted for 45 countries in Europe. YLD was restricted to a list of specific health conditions associated with being at risk of developing severe consequences from COVID-19 based on guidance from the United Kingdom Government. This guidance also identified individuals aged 70 years and above as being at higher risk of developing severe health consequences. Study outcomes were defined as: (i) proportion of population aged 70 years and above; and (ii) rate of YLD for COVID-19 vulnerable health conditions across all ages. Bivariate groupings were established for each outcome and combined to establish overall population-level vulnerability.

RESULTS

Countries with the highest proportions of elderly residents were Italy, Greece, Germany, Portugal and Finland. When assessments of population-level YLD rates for COVID-19 vulnerable health conditions were made, the highest rates were observed for Bulgaria, Czechia, Croatia, Hungary and Bosnia and Herzegovina. A bivariate analysis indicated that the countries at high-risk across both measures of vulnerability were: Bulgaria; Portugal; Latvia; Lithuania; Greece; Germany; Estonia; and Sweden.

CONCLUSION

Routine estimates of population structures and non-fatal burden of disease measures can be usefully combined to create composite indicators of vulnerability for rapid assessments, in this case to severe health consequences from COVID-19. Countries with available results for sub-national regions within their country, or national burden of disease studies that also use sub-national levels for burden quantifications, should consider using non-fatal burden of disease estimates to estimate geographical vulnerability to COVID-19.

Adjusting for comorbidity in incidence-based DALY calculations: an individual-based modeling approach

Background

The co-occurrence of two or more medical conditions in the same individual is not uncommon. If disability-adjusted life year (DALY) calculations are carried out for each condition separately, multimorbidity may lead to an overestimation of the morbidity component, the Years Lived with Disability (YLD). Adjusting for comorbidity may be straightforward if all symptoms have same onset and duration; however, when the comorbid health states occur at different time points, an analytical solution to the comorbidity problem becomes more complex. The aim of this study was to develop an individual-based modelling (IBM) approach to adjust incidence-based disease burden estimation for multimorbidity that allows simulating hypothetical individuals and tracking their disease history, including possible comorbidities, over time.

Methods

We demonstrated the IBM approach using an example of external comorbidity, i.e., colon cancer comorbid with healthcare-associated pneumonia (HAP) and by assuming an independent multiplicative model. First, each cumulative progression probabilities were converted to a daily transition probabilities. Second, disability weights for simultaneously experienced health states and duration in each health state were determined. Third, YLD, adjusted for comorbidity, was calculated at every time step. We simulated a cohort of 1000 colorectal cancer patients aged 65 years. Ninety-five percent uncertainty intervals around median YLD values were estimated by Monte Carlo methods.

Results

The median estimated YLD per 1000 cases (due to both cancer and HAP) adjusted for co-morbidity was 545 YLD/1000 (95% interval: 513–585). The impact of not adjusting disability weights for co-existent health states varied from minimal to small; YLD for colorectal cancer would be overestimated only slightly – by 1.6 YLD/1000 – by not adjusting for concurrent HAP. YLD for those HAP patients who have concurrent early-stage colorectal cancer would be overestimated by 2.3 YLD/1000.

Conclusions

The computation of disease burden in the presence of multimorbidity using the incidence-based DALY approach can be handled through IBM. Our approach can be extended to other, more complicated multimorbidity scenarios which are responsible for a high current global disease burden, such as tuberculosis and HIV infection.

The Burden of Bancroftian Filariasis in Nigeria: A Review

BACKGROUND

Lymphatic filariasis (LF) is a neglected tropical disease (NTD) vectored by mosquito; and people in rural areas are mostly at risk of infection. Pooling prevalence data across the six geo-political zones of Nigeria is expected to provide a clearer insight into the burden of the disease as this information could guide towards planning eradication programmes.

METHODS

Search for pertinent literature was done on Google Scholar, African Journal Online (AJOL) and PubMed databases using relevant keywords. Studies on the prevalence of LF due to Wuchereria bancrofti in Nigeria were selected and reviewed. Prevalence data from the different states were further organized into the six geopolitical zones and analyzed.

RESULTS

Of the 36 states in Nigeria, prevalence data were available only for 19 states. Furthermore, in the six geopolitical zones, North-West had the highest disease burden (44 per 10 000) of Years Lived with Disability (YLD), while North-Central (4 per 10 000) had the lowest disease burden.

CONCLUSION

Result are largely attributed to the prevailing conditions in the different zones. In view of ensuring a successful control plan and eventual eradication of the disease, a comprehensive national survey in every state should be carried out using more sensitive tools.

Prioritising the development of severity distributions in burden of disease studies for countries in the European region

Severity distributions are a means of summarising the range of health loss suffered to disease which enables estimates of disease occurrence to be paired with disability weights to estimate Years Lost to Disability (YLD) in burden of disease studies. There is a lack of current data exploring severity distributions, which has led to the Global Burden of Disease (GBD) study relying on using the same severity distributions across countries and regions across the world. This is also largely true for some national studies, although there are exceptions. Recent evidence has raised concerns that severity distributions are unlikely to be generalisable as major differences arise when using country-specific data to develop severity distributions. These issues raise uncertainties over interpreting YLD estimates, particularly if they are being used to develop and influence policies and to determine priorities across diseases and populations. It is clear that GBD researchers and those carrying out national studies need to work towards ensuring that estimates are based upon country-specific data, and, if possible, that the impact of assumptions are fully tested and understood. There is a lack of strategy about if, where, and how, this could be achieved, particularly around how efforts should be prioritised. This commentary advocates and presents a possible strategic approach to better understanding how efforts may be best placed.

How do world and European standard populations impact burden of disease studies? A case study of disability-adjusted life years (DALYs) in Scotland

Background

Disability-Adjusted Life Years (DALYs) are an established method for quantifying population health needs and guiding prioritisation decisions. Global Burden of Disease (GBD) estimates aim to ensure comparability between countries and over time by using age-standardised rates (ASR) to account for differences in the age structure of different populations. Different standard populations are used for this purpose but it is not widely appreciated that the choice of standard may affect not only the resulting rates but also the rankings of causes of DALYs. We aimed to evaluate the impact of the choice of standard, using the example of Scotland.

Methods

DALY estimates were derived from the 2016 Scottish Burden of Disease (SBoD) study for an abridged list of 68 causes of disease/injury, representing a three-year annual average across 2014-16. Crude DALY rates were calculated using Scottish national population estimates. DALY ASRs standardised using the GBD World Standard Population (GBD WSP) were compared to those using the 2013 European Standard Population (ESP2013). Differences in ASR and in rank order within the cause list were summarised for all-cause and for each individual cause.

Results

The ranking of causes by DALYs were similar using crude rates or ASR (ESP2013). All-cause DALY rates using ASR (GBD WSP) were around 26% lower. Overall 58 out of 68 causes had a lower ASR using GBD WSP compared with ESP2013, with the largest falls occurring for leading causes of mortality observed in older ages. Gains in ASR were much smaller in absolute scale and largely affected causes that operated early in life. These differences were associated with a substantial change to the ranking of causes when GBD WSP was used compared with ESP2013.

Conclusion

Disease rankings based on DALY ASRs are strongly influenced by the choice of standard population. While GBD WSP offers international comparability, within-country analyses based on DALY ASRs should reflect local age structures. For European countries, including Scotland, ESP2013 may better guide local priority setting by avoiding large disparities occurring between crude and age-standardised results sets, which could potentially confuse non-technical audiences.

Disability Adjusted Life Years (DALYs) in Terms of Years of Life Lost (YLL) Due to Premature Adult Mortalities and Postneonatal Infant Mortalities Attributed to PM2.5 and PM10 Exposures in Kuwait

Ambient air pollution in terms of fine and coarse particulate matter (PM_2.5 and PM₁₀) has been shown to increase adult and infant mortalities. Most studies have estimated the risk of mortalities through attributable proportions and number of excess cases with no reference to the time lost due to premature mortalities. Disability adjusted life years (DALYs) are necessary to measure the health impact of Ambient particulate matter (PM) over time. In this study, we used life-tables for three years (2014⁻2016) to estimate the years of life lost (YLL), a main component of DALYs, for adult mortalities (age 30+ years) and postneonatal infant mortalities (age 28+ days⁻1 year) associated with PM_2.5 exposure and PM₁₀ exposure, respectively. The annual average of PM_2.5 and PM₁₀ concentrations were recorded as 87.9 μg/m³ and 167.5 μg/m³, which are 8 times greater than the World Health Organization (WHO) air quality guidelines of 10 μg/m³ and 20 μg/m³, respectively. Results indicated a total of 252.18 (95% CI: 170.69⁻322.92) YLL for all ages with an increase of 27,474.61 (95% CI: 18,483.02⁻35,370.58) YLL over 10 years. The expected life remaining (ELR) calculations showed that 30- and 65-year-old persons would gain 2.34 years and 1.93 years, respectively if the current PM_2.5 exposure levels were reduced to the WHO interim targets (IT-1 = 35 μg/m³). Newborns and 1-year old children may live 79.81 and 78.94 years, respectively with an increase in average life expectancy of 2.65 years if the WHO PM₁₀ interim targets were met (IT-1 = 70 μg/m³). Sensitivity analyses for YLL were carried out for the years 2015, 2025, and 2045 and showed that the years of life would increase significantly for age groups between 30 and 85. Life expectancy, especially for the elderly (≥60 years), would increase at higher rates if PM_2.5 levels were reduced further. This study can be helpful for the assessment of poor air quality represented by PM_2.5 and PM₁₀ exposures in causing premature adult mortalities and postneonatal infant mortalities in developing countries with high ambient air pollution. Information in this article adds insights to the sustainable development goals (SDG 3.9.1 and 11.6.2) related to the reduction of mortality rates attributed to ambient air levels of coarse and fine particulate matter.

Disability-Adjusted Life Years for Cancer in 2010⁻2014: A Regional Approach in Mexico

The disability-adjusted life years (DALYs) were used to estimate the regional (state of Colima, Mexico) cancer burden in 2010⁻2014. The years of life lost (YLL) were estimated with mortality data and years lived with disability (YLD) using incidence data. The DALYs were calculated as the arithmetic addition of YLL and YLD. Sex and cancer site-specific estimations were made and DALY rates were used to identify the leading causes of disease burden. Data from 2532 deaths were analyzed and, for all malignant tumors combined, 18,712.9 DALYs and 20,243.3 DALYs were estimated in males and females respectively. The overall contribution of YLL in DALY estimates was higher among females (93.7% vs. 87.4%). Age-standardized DALY rates (and 95% confidence intervals, CI) per 100,000 inhabitants were used to rank the leading causes of disease burden and, among males, malignant tumors from the prostate, lower respiratory tract, and colon and rectum accounted the highest rates (45.7, 95% CI 32.7⁻59.3; 37.6, 95% CI 25.7⁻49.9; and 25.9, 95% CI 16.0⁻36.1 DALYs). Breast, cervix uteri, and lower respiratory tract cancer showed the highest burden in females (66.0, 95% CI 50.3⁻82.4; 44.4, 95% CI 31.5⁻57.7; and 20.9, 95% CI 12.0⁻30.0 DALYs). The present study provides an indication of the burden of cancer at the regional level, underscoring the need to expand cancer prevention, screening, and awareness programs, as well as to improve early diagnosis and medical treatment.

Prevalence and Years of Life Lost due to Disability from Dental Caries among Children and Adolescents in Western China, 1990-2015

OBJECTIVE

To analyze the prevalence and years lived with disability (YLD) from dental caries among children and adolescents and the time trends over the past two decades in Sichuan province, the largest province in west China.

METHODS

Based on the Global Burden of Disease Study 2015 (GBD2015), which systematically assessed the epidemiological characteristics of major diseases and their transitions by country and region from 1990 to 2015, we extracted the estimated results for China. We then used the Bayesian meta-regression method to estimate the sex- and age-specific prevalences and YLDs from dental caries among children and adolescents under 15 years old in Sichuan province and compared them with global and national indicators for the same period.

RESULTS

In 2015, there were almost 6 million cases of dental caries in children and adolescents (aged < 15 years) in Sichuan province, accounting for 6% of the total cases in China. For children under 5 years, the prevalence of deciduous caries was 55.9%, and the YLDs value was 10.8 per 100,000, while it was 24.3% and 5.1 per 100,000 respectively among 5- to 14-year-olds; for those aged 5 to 14 years, the prevalence of permanent caries was 21.5%, and the YLDs value was 11.5 per 100,000. From 1990 to 2015, the prevalence of dental caries for children under 5 years increased substantially, by 16.2%, and the YLDs increased by 8.7%. Among those aged 5 to 14 years, the prevalence increased and the YLDs decreased.

CONCLUSION

Dental caries remains a huge health burden in Western China. In contrast to the global and national data, the trend has increased rapidly over the past 25 years in this region. This work provides suggestions for the prevention and control for oral health in China with the policy of two-child.

Burden of injury of serious road injuries in six EU countries

BACKGROUND

Information about the burden of (non-fatal) road traffic injury is very useful to further improve road safety policy. Previous studies calculated the burden of injury in individual countries. This paper estimates and compares the burden of non-fatal serious road traffic injuries in six EU countries/regions: Austria, Belgium, England, The Netherlands, the Rhône region in France and Spain.

METHODS

It is a cross-sectional study based on hospital discharge databases.

POPULATION

of study are patients hospitalized with MAIS3+ due to road traffic injuries. The burden of injury (expressed in years lived with disability (YLD)) is calculated applying a method that is developed within the INTEGRIS study. The method assigns estimated disability information to the casualties using the EUROCOST injury classification.

RESULTS

The average burden per MAIS3+ casualty varies between 2.4 YLD and 3.2 YLD per casualty. About 90% of the total burden of injury of MAIS3+ casualties is due to lifelong consequences that are experienced by 19% to 33% of the MAIS3+ casualties. Head injuries, spinal cord injuries and injuries to the lower extremities are responsible for more than 90% of the total burden of MAIS3+ road traffic injuries. Results per transport mode differ between the countries. Differences between countries are mainly due to differences in age distribution and in the distribution over EUROCOST injury groups of the casualties.

CONCLUSION

The analyses presented in this paper can support further improvement of road safety policy. Countermeasures could for example be focused at reducing skull and brain injuries, spinal cord injuries and injuries to the lower extremities, as these injuries are responsible for more than 90% of the total burden of injury of MAIS3+ casualties.

Characterization and fine-mapping of a novel premature leaf senescence mutant yellow leaf and dwarf 1 in rice

Leaves are the main organs in which photosynthates are produced. Leaf senescence facilitates the translocation of photosynthates and nutrients from source to sink, which is important for plant development and especially for crop yield. However, the molecular mechanism of leaf senescence is unknown. Here, we identified a mutant, yellow leaf and dwarf 1 (yld1), which exhibited decreased plant height and premature leaf senescence. Nitroblue tetrazolium and diamiobenzidine staining analyses revealed that the concentrations of reactive oxygen species were higher in yld1 leaves than in wild type leaves. The photosynthetic pigment contents were significantly decreased in yld1. The yld1 chloroplasts had collapsed and were filled with abnormal starch granules. Combining bulk segregant and MutMap gene mapping approaches, the mutation responsible for the yld1 phenotype was mapped to a 7.3 Mb centromeric region, and three non-synonymous single nucleotide polymorphisms located in three novel genes were identified in this region. The expression patterns of the three candidate genes indicated that LOC_Os06g29380 had the most potential for functional verification. Plant hormone measurements showed that salicylic acid was highly accumulated in yld1 leaves when compared with wild type leaves, and yld1 was more sensitive to salicylic acid than wild type. This work lays the foundation for understanding the molecular regulatory mechanism of leaf senescence, and may reveal new connections among the molecular pathways related to leaf senescence, starch metabolism and salicylic acid signaling.

Estimation of lung cancer burden in Australia, the Philippines, and Singapore: an evaluation of disability adjusted life years

Objective:

Lung cancer is one of the leading cancers and major causes of cancer mortality worldwide. The economic burden associated with the high mortality of lung cancer is high, which accounts for nearly $180 billion on a global scale in 2008. This paper aims to understand the economic burden of lung cancer in terms of disability adjusted life years (DALY) in Australia, the Philippines, and Singapore.

Methods:

The years of life lost (YLL) and years lost due to disability (YLD) were calculated using the formula developed by Murray and Lopez in 1996 as part of a comprehensive assessment of mortality and disability for diseases, injuries and risk factors in 1990 and projected to 2020. The same formula is represented in the Global Burden of Disease template provided by the World Health Organization. Appropriate assumptions were made when data were unavailable and projections were performed using regression analysis to obtain data for 2015.

Results:

The total DALYs due to lung cancer in Australia, the Philippines, and Singapore were 91,695, 38,584, and 12,435, respectively, and the corresponding DALY rates per a population of 1,000 were 4.0, 0.4, and 2.2, respectively, with a discount rate of 3%. When researchers calculated DALYs without the discount rate, the burden of disease increased substantially; the DALYs were 117,438 in Australia, 50,977 in the Philippines, and 16,379 in Singapore. Overall, YLL or premature death accounted for more than 95% of DALYs in these countries.

Conclusions:

Strategies for prevention, early diagnosis, and prompt treatment must be devised for diseases where the major burden is due to mortality.

Health burden of serious road injuries in the Netherlands

BACKGROUND

The consequences of injuries in terms of disabilities and health burden are relevant for policy making. This article provides an overview of the current knowledge on this topic and discusses the health burden of serious road injuries in The Netherlands.

METHODS

The overview of current knowledge on disabilities following a road crash is based on a literature review. The health burden of serious road injuries is quantified in terms of years lived with disability (YLD), by combining incidence data from the Dutch hospital discharge register with information about temporary and lifelong disability.

RESULTS

Literature shows that road traffic injuries can have a major impact on victims' physical and psychological well-being and functioning. Reported proportions of people with disability vary between 11 and 80% depending on the type of casualties, time elapsed since the crash, and the health impacts considered. Together, all casualties involving serious injuries in The Netherlands in 2009 account for about 38,000 YLD, compared to 25,000 years of life lost (YLL) of fatalities. Ninety percent of the burden of injury is due to lifelong consequences that are experienced by 20% of all those seriously injured in road accidents. Lower leg injuries and head injuries represent a high share in the total burden of injury as have cyclists that are injured in a crash without a motorized vehicle. Pedestrians and powered 2-wheeler users show the highest burden of injury per casualty.

CONCLUSION

Given their major impacts and contribution to health burden, road policy making should also be aimed at reducing the number of serious road injuries and limiting the resulting health impacts.

Burden of diabetes mellitus attributable to demographic levels in Qatar: an emerging public health problem

BACKGROUND

Diabetes is one of the main contributors to ill health and premature mortality worldwide and its prevalence has been rising during the last decades.

AIM

The aim of the present study was to quantify the burden of disease in terms of deaths and loss of healthy life years (DALYs) attributed to diabetes by its demographic levels in the State of Qatar.

MATERIALS AND METHODS

The methods were largely based on the established Global Burden of Disease methodology and use the burden of disease in terms of disability adjusted life years (DALYs) and the years lost due to disability (YLD) as the outcome measure. We calculated years lost due to disability (YLD) and years life lost (YLL) attributable to diabetes. The study was conducted during the period from June 2013 to January 2014.

RESULTS

The study findings revealed that disability adjusted life years (DALYs) has been increasing across the years and reached to 4.35 in 2011 from 2.58 in 2007. DALYs for men was remarkably higher than women during the period (2007-2011). Diabetes mellitus was the 6th leading cause of disease burden in Qatar (3.8%). The YLD showed a sharp increase in men (2.52 in 2011 from 1.34 in 2007) and women (1.05 in 2011 from 0.33 in 2007) during the year 2011. YLL portion of women enlarged considerably in 2011 (0.10) compared to 2010 (0.04). YLL for men and women was fluctuating across the years with a decrease in 2011 (18%) from 2007 (35%). Men and women in the age group 30-44 years had the highest peak across the years.

CONCLUSION

The study findings revealed that diabetes disease burden was considerably high in Qatar, particularly in the working age group. DALYs has been increasing across the years.

Health impact assessment of increasing public transport and cycling use in Barcelona: a morbidity and burden of disease approach

OBJECTIVE

Quantify the health impacts on morbidity of reduced car trips and increased public transport and cycling trips.

METHODS

A health impact assessment study of morbidity outcomes related to replacing car trips in Barcelona metropolitan (3,231,458 inhabitants). Through 8 different transport scenarios, the number of cases of disease or injuries related to physical activity, particulate matter air pollution <2.5 μm (PM2.5) and traffic incidents in travelers was estimated. We also estimate PM2.5 exposure and cases of disease in the general population.

RESULTS

A 40% reduction in long-duration car trips substituted by public transport and cycling trips resulted in annual reductions of 127 cases of diabetes, 44 of cardiovascular diseases, 30 of dementia, 16 minor injuries, 0.14 major injuries, 11 of breast cancer and 3 of colon-cancer, amounting to a total reduction of 302 Disability Adjusted Life Years per year in travelers. The reduction in PM2.5 exposure in the general population resulted in annual reductions of 7 cases of low birth weight, 6 of preterm birth, 1 of cardiovascular disease and 1 of lower respiratory tract infection.

CONCLUSIONS

Transport policies to reduce car trips could produce important health benefits in terms of reduced morbidity, particularly for those who take up active transportation.

The epidemiology of cardiovascular diseases in sub-Saharan Africa: the Global Burden of Diseases, Injuries and Risk Factors 2010 Study

The epidemiology of cardiovascular diseases in sub-Saharan Africa is unique among world regions, with about half of cardiovascular diseases (CVDs) due to causes other than atherosclerosis. CVD epidemiology data are sparse and of uneven quality in sub-Saharan Africa. Using the available data, the Global Burden of Diseases, Risk Factors, and Injuries (GBD) 2010 Study estimated CVD mortality and burden of disease in sub-Saharan Africa in 1990 and 2010. The leading CVD cause of death and disability in 2010 in sub-Saharan Africa was stroke; the largest relative increases in CVD burden between 1990 and 2010 were in atrial fibrillation and peripheral arterial disease. CVD deaths constituted only 8.8% of all deaths and 3.5% of all disability-adjusted life years (DALYs) in sub-Sahara Africa, less than a quarter of the proportion of deaths and burden attributed to CVD in high income regions. However, CVD deaths in sub-Saharan Africa occur at younger ages on average than in the rest of the world. It remains uncertain if increased urbanization and life expectancy in some parts of sub-Saharan African nations will transition the region to higher CVD burden in future years.

Systematic review of foodborne burden of disease studies: quality assessment of data and methodology

Burden of disease (BoD) studies aim to identify the public health impact of different health problems and risk factors. To assess BoD, detailed knowledge is needed on epidemiology, disability and mortality in the population under study. This is particularly challenging for foodborne disease, because of the multitude of causative agents and their health effects. The purpose of this study is to systematically review the methodology of foodborne BoD studies. Three key questions were addressed: 1) which data sources and approaches were used to assess mortality, morbidity and disability?, 2) which methodological choices were made to calculate Disability Adjusted Life Years (DALY), and 3) were uncertainty analyses performed and if so, how? Studies (1990-June 2012) in international peer-reviewed journals and grey literature were identified with main inclusion criteria being that the study assessed disability adjusted life years related to foodborne disease. Twenty-four studies met our inclusion criteria. To assess incidence or prevalence of foodborne disease in the population, four approaches could be distinguished, each using a different data source as a starting point, namely 1) laboratory-confirmed cases, 2) cohort or cross-sectional data, 3) syndrome surveillance data and 4) exposure data. Considerable variation existed in BoD methodology (e.g. disability weights, discounting, age-weighting). Almost all studies analyzed the effect of uncertainty as a result of possible imprecision in the parameter values. Awareness of epidemiological and methodological rigor between foodborne BoD studies using the DALY approach is a critical priority for advancing burden of disease studies. Harmonization of methodology that is used and of modeling techniques and high quality data can enlarge the detection of real variation in DALY outcomes between pathogens, between populations or over time. This harmonization can be achieved by identifying substantial data gaps and uncertainty and establish which sequelae of foodborne disease agents should be included in BoD calculations.