11 research outputs found
Characterization of the affective behavioral effects of chronic adolescent exposure to the cannabinoid receptor agonist HU-210 in female rats
Tese de mestrado, Neurociências, Universidade de Lisboa, Faculdade de Medicina, 2019Os canabinóides, agonistas dos receptores do sistema endocanabinóide (SEC), são as drogas ilegais mais consumidas no mundo, sendo os adolescentes um dos grupos etários em que o consumo destas substâncias é mais prevalente.
A adolescência representa um período crítico do neurodesenvolvimento, no qual o sistema nervoso central é extensamente reorganizado – sendo, também, um período de vulnerabilidade aumentada aos efeitos de influências externas, como por exemplo drogas de abuso. Criticamente, grande parte destas alterações neuronais são mediadas e/ou moduladas pelo SEC sendo, portanto, expectável que o uso de drogas que interagem com esse sistema cause alterações profundas, e possivelmente persistentes, no
funcionamento do sistema nervoso. Congruentemente, dados obtidos quer com humanos, quer com roedores, sugerem que a exposição crónica adolescente a canabinóides tem efeitos deletérios quer ao nível da função neurocognitiva, quer ao nível do funcionamento afectivo.
Assim, estudos epidemiológicos em populações humanas têm demonstrado que indivíduos adultos, que enquanto adolescentes foram consumidores crónicos de canabinóides, apresentam um risco aumentado de serem diagnosticados com perturbações de ansiedade e/ou perturbações depressivas. Mais ainda, devido a
um conjunto ainda não totalmente estudado de factores, este aumento de risco é mais marcado na população do sexo feminino.
Em linha com estas observações, estudos experimentais com roedores têm consistentemente demonstrado que a exposição crónica adolescente a canabinóides induz um conjunto profundo e diversificado de alterações a nível molecular, morfológico, estrutural, funcional e comportamental. Em relação ao último, estudos comportamentais têm repetidamente demonstrado que animais adultos expostos a canabinóides durante a adolescência apresentam défices não só em tarefas de função cognitiva, como em testes de função afectiva – apresentando alterações comportamentais que sugerem um efeito prodepressivo desta exposição, que, replicando os dados humanos, é mais marcado em fêmeas.
Uma limitação da literatura até agora é, no entanto, o uso de um conjunto limitado de canabinóides. De facto, praticamente todos os estudos usaram apenas uma de três substâncias, o que levanta a possibilidade de existirem outros canabinóides cujos efeitos diferem dos até agora observados, o que – a ser verdade – representaria um problema importante na literatura.
O presente trabalho pretende averiguar essa possibilidade, ao estudar o HU-210, um potente agonista total e não-selectivo dos receptores canabinóides 1 (CB1R) e 2 (CB2R). Apesar de este fármaco ser amplamente usado em investigação sobre o SEC, e já ter sido encontrado em substitutos sintéticos de canábis, não existe – à data – nenhum relato publicado acerca do impacto que a exposição crónica adolescente a HU-210 possa ter no funcionamento afectivo. Assim, o presente trabalho consiste num conjunto de quatro experiências desenhadas para caracterizar esses efeitos.
Na primeira experiência ratos, Wistar fêmea com 35 dias de idade (PND 35) foram administrados HU-210 diariamente, durante 15 dias, num plano de doses ascendentes (PND 35-39: 25μg/kg; PND 42-46: 50μg/kg; PND 49-53: 100μg/kg, ou solução veiculo equivalente). Após o fim da administração, os animais foram deixados durante 27 dias – de modo a que efeitos residuais, ou resultantes de abstinência, pudessem ser minimizados e permitindo que os animais atingissem a idade adulta – ao fim dos quais foram testados numa bateria de testes comportamentais. Especificamente, para medir alterações ao nível do comportamento ansioso, os animais foram testados no Elevated Plus Maze (EPM; PND 80), Open Field Test (OFT; PND 80 e 81) e Marble Burying Test (MBT; PND 91). Para determinar os efeitos do tratamento no comportamento social foi utilizado o Social Interaction Test (SIT; PND 82). Finalmente, para avaliar os efeitos da exposição a HU-210 nas dimensões de stress-coping e de resposta à recompensa, do comportamento depressivo, os animais foram testados no Modified Forced Swim Test (mFST; PND 85) e no Sucrose Preference Test (SPT; PND 88-91), respectivamente. Adicionalmente, o peso dos animais foi registado ao longo da duração da experiência.
Análise dos resultados obtidos revelou que, tal como descrito previamente para outros canabinóides, a exposição a HU-210 não induziu alterações persistentes ao nível do comportamento ansioso, em nenhum dos três testes. Contrariamente ao anteriormente descrito, não foi observada qualquer alteração no SIT, indicando a ausência de efeitos persistentes. No que diz respeito ao comportamento depressivo, foi registado um decréscimo ligeiro no comportamento de trepar, no mFST – sugerindo a possibilidade de alterações de stress-coping – sem qualquer diferença nos outros comportamentos. No SPT não foram encontradas diferenças quer na quantidade de sacarose consumida, quer na preferência relativa por sacarose, indicando que a resposta à recompensa não está alterada. Finalmente, em linha com estudos anteriores, a exposição a HU-210 induziu decréscimos marcados no ganho de peso, que persistiram durante 15 dias após o fim da administração.
Dado que os resultados da experiência 1 não foram os esperados, e que várias limitações foram identificadas no protocolo, a experiência 2 foi desenhada para – de novo – testar os efeitos a longo-termo da exposição crónica adolescente a HU-210. Assim, ratos Sprague-Dawley fêmea receberam duas injecções diárias de HU-210 durante 11 dias, seguindo um padrão de doses ascendentes (PND 35-37: 25μg/kg; PND 38-41: 50μg/kg; PND 42-45: 100μg/kg ou veículo equivalente). Após o término da administração, os animais foram deixados em repouso durante 30 dias, ao fim dos quais lhes foi aplicada a mesma bateria de testes comportamentais usada na experiência anterior. Adicionalmente, de modo a determinar os efeitos da exposição adolescente nos níveis de proteína CB1R, amostras de tecido do hipocampo, estriado e córtex pré-frontal, foram recolhidas após o fim da bateria comportamental (PND 88), tendo os níveis de CB1R sido avaliados através de western blotting.
Tal como na experiência 1, não foram encontradas quaisquer alterações no comportamento ansioso, ou no comportamento social, e foi observado um decréscimo marcado no ganho de peso que – mais uma vez – persistiu durante 15 dias pós-última administração. No entanto, em contraste quer com a experiência anterior, quer com a literatura, no mFST também não foram observadas alterações. Semelhantemente, no SPT, o desempenho foi igual entre grupos. Em linha com a ausência de alterações comportamentais, não se detectaram alterações nos níveis de proteína CB1R em nenhuma das três regiões estudadas.
Dada a discordância entre os resultados obtidos na experiência 2 e o descrito na literatura, a experiência 3 consistiu em avaliar se a administração adolescente de HU-210 tinha de facto algum efeito mensurável a curto-prazo que poderia ter desaparecido, durante o interregno de 30 dias entre a última administração e o início dos testes. Para isso uma nova série de ratos Sprague-Dawley fêmea foi manipulada como descrito
na experiência 2, e testada no OFT e mFST, nos dois dias após a última administração de HU-210 (PND 46-47). Adicionalmente, amostras de tecido para western blot foram recolhidas no dia após o fim dos testes comportamentais (PND 48).
Surpreendentemente, apesar de nenhuma alteração ter sido encontrada no OFT, no mFST os animais mostraram um padrão comportamental marcado e sugestivo de um efeito antidepressivo do tratamento, com decréscimos no tempo passado em imobilidade e aumentos no tempo passado a trepar. Mais ainda, análise do western blot revelou um decréscimo de cerca de 50% nos níveis de proteína CB1R, na região hipocampal, sem alterações nas restantes.
Uma vez que os resultados na experiência 3, no que respeita aos parâmetros do mFST, foram inteiramente inesperados, e as alterações moleculares encontradas foram incongruentes com um efeito antidepressivo, a experiência 4 foi desenhada para mais uma vez avaliar os efeitos imediatos da exposição adolescente a HU-210, recorrendo a outros dois testes, frequentemente usados para testar ansiedade e depressão, o EPM e o SPT, respectivamente. Assim, uma nova série de ratos Sprague-Dawley fêmea foi manipulada como descrito nas experiências 2 e 3, e testada no EPM (PND 46) e SPT (PND 46-49) nos dias que se seguiram à última administração de HU-210.
Em linha com o encontrado na experiência 3, não foram observadas alterações no comportamento ansioso no EPM. No entanto, em contraste marcado, no SPT, o grupo tratado com HU-210 consumiu significativamente menos sacarose que os controlos e mostrou, igualmente, um decréscimo acentuado na preferência pela mesma – alterações sugestivas de um efeito prodepressivo.
No geral os resultados obtidos ao longo das quatro experiências sugerem que, apesar de o HU-210 ser capaz de induzir alterações marcadas no funcionamento afectivo, estas alterações desaparecem após algum tempo. Mais ainda, o facto deste fármaco não induzir efeitos a longo termo sugere a possibilidade de que diferenças nas características farmacológicas dos vários canabinóides possam ter influência importante e imprevisível, nos resultados observados na literatura. Especificamente, é possível que a ausência de efeitos duradouros após exposição crónica adolescente a HU-210, derive de diferenças farmacodinâmicas deste canabinóide quer ao nível da sua interacção com o SEC, quer ao nível de possíveis interacções com outros sistemas de neurotransmissão/neuromodulação. Assim, a principal conclusão derivada deste trabalho prende-se com a noção de que, ao usar apenas um conjunto limitado de agonistas dos receptores canabinóides, se está a incorrer dois riscos: por um lado, o risco de ignorar a totalidade dos possíveis efeitos da modulação do SEC, e por outro, se formarem conclusões extrapoladas a partir de dados obtidos com vários fármacos diferentes, cuja farmacologia e efeitos podem não ser totalmente comparáveis. Ambos estes riscos têm fortes implicações para a interpretabilidade e utilidade da investigação feita usando canabinóides e acerca do potencial benéfico e/ou deletério da manipulação farmacológica do SEC.Cannabinoids, drugs acting as agonists at the cannabinoid receptors comprising the endocannabinoid system (ECS), are the most widely used illegal drug class in the world, with adolescents being one of the age group where the use of such drugs is most prevalent. Adolescence represents a critical neurodevelopmental period, during which the central nervous system undergoes extensive reorganization, with this development being heavily mediated by the ECS. Thus, it is expectable that the adolescent use of drugs targeting that system will lead to profound, and possibly permanent, alterations in nervous system functioning. Accordingly, both human and rodent studies suggests that chronic adolescent exposure to cannabinoids induces deleterious effects at both the cognitive and affective functioning levels:
Epidemiological studies of human populations have shown adults, who were chronic cannabinoid users as adolescents, to be at an increased risk of being diagnosed with both anxiety and/or depressive disorders, with risk being even greater for females. Similarly, rodent experimental studies have consistently demonstrated that chronic adolescent cannabinoid exposure leads to lasting deficits not just in tasks of cognitive function, but in tests of affective functioning, as well – with behavioral alterations suggesting a prodepressant-like effect of cannabinoid treatment which, as in humans, is more marked in females.
One limitation of the literature is, however, the overreliance on a limited set of cannabinoids, raising the possibility that other, yet unstudied cannabinoids, may have differing effects from those reported thus far – a significant problem for the field, if true. As such the present work aimed, through four experiments, to test that possibility, by characterizing the affective impact of chronic adolescent exposure to HU-210 – a potent non-selective full-agonist at both cannabinoid receptors 1 (CB1R) and 2 (CB2R) – that, despite being widely used in ECS research, has yet to be studied in this regard.
In the first experiment, female Wistar rats aged 35 days (PND 35) were administered HU-210 daily, for a 15-day, in an escalating dosing schedule (PND 35-39: 25μg/kg; PND 42-46: 50μg/kg; PND 49-53: 100μg/kg, or equivalent vehicle solution). Following a 27-day washout period animals were put through a battery of behavioral tests: to assess anxiety-like behavior the Elevated Plus Maze (EPM; PND 80), Open Field Test (OFT; PND 80-81) and Marble Burying Test (MBT; PND 91) were used; to assess social behavior, the Social Interaction Test (SIT; PND 82) was employed; to assess the stress-coping and reward functioning dimensions of depressive-like behavior the Modified Forced Swim (mFST; PND 85) and the Sucrose Preference Tests (SPT; PND 88-91) were used, respectively.
Data showed that, as previously described for other cannabinoids, adolescent exposure to HU-210 did not lead to persistent alterations at the level of anxiety-like behavior. However, contrarily to what had been previously described, in the SIT no alteration was observed, suggesting no lasting treatment-induced impairments. With regards to depressive-like behavior, a slight decrease in climbing behavior was observed in the mFST – suggesting the possibility of altered stress-coping – but no changes were found in any of the other behaviors scored. Moreover, no changes were found in the SPT, pointing towards reward functioning being intact.
Experiment 2 was designed to again test the long-term effects of chronic adolescent HU-210 exposure, controlling for confounds that may have biased the results of experiment 1. As such, female Sprague Dawley rats, received twice-daily intraperitoneal injections of HU-210 for a period 11-days, following an escalating dosing schedule (PND 35-37: 25μg/kg; PND 38-41: 50μg/kg; PND 42-45: 100μg/kg or equivalent vehicle solution). After a 30-day washout period, animals were tested using the same behavioral testing battery used in the previous experiment. Additionally, so as to determine the effects of exposure on CB1R protein levels, through western blotting, tissue samples were collected from the hippocampus, striatum and prefrontal cortex (PND 88).
As was the case in experiment 1, no changes were found in anxiety-like or social behaviors. However, in contrast with both the previous experiment and the literature, no changes were observed in any of the mFST parameters, nor in the SPT. Furthermore, in line with the absence of behavioral alterations, CB1R protein levels were found to be unaltered in all the three brain regions studied.
Given the discrepancy between the results obtained in experiment 2 and those described in the literature, experiment 3 was performed so as to determine whether adolescent HU-210 administration did, in fact, have any measurable short-term effect, that might be normalized during washout. To that end a new set of female Sprague-Dawley rats, was manipulated as described in experiment 2, and tested in both the OFT and the mFST, in the two days following the last drug injection (PND 46-47). Additionally, tissue samples for western blotting were collected from the same brain regions (PND 48).
Surprisingly, in the mFST animals presented a behavioral pattern suggestive of an antidepressant-like effect of treatment – with decreased in the time spent in immobility and increased time spent climbing. Critically, this effect occurred in the absence of any alterations in the OFT. Moreover, a decrease of approximately 50% in hippocampal CB1R protein levels was observed, with no changes in the remaining regions studied.
Since the results of experiment 3 were unexpected, and the molecular alterations observed were incongruous with an antidepressant-like effect, experiment 4 was performed to complement them, by using two other tests: the EPM and the SPT. As such, a new set of female Sprague-Dawley rats was manipulated as described in experiments 2 and 3, and tested in the EPM (PND 46) and SPT (PND 46-49) on the days following the last drug administration.
In line with the previous experiment, no alterations were observed in anxiety-like behavior. However, contrastingly, the HU-210-treated group presented markedly decreased sucrose intake and relative sucrose preference, in the SPT – suggesting a prodepressant treatment effect.
In general, the results obtained across the four experiments suggest that, despite HU-210 being able to alter affective functioning, these alterations are normalized after sufficient washout time. Moreover, the fact that this drug did not induce long-term effects suggests the possibility that differences in the pharmacological properties of cannabinoids – either in terms of ECS or non-ECS interactions – may influence results observed in the literature, in important and unpredictable ways. As such, the primary conclusion derived from the present work pertains to the notion that, by relying on a limited set of cannabinoid receptor agonists, one may be at risk of ignoring the totality of the possible effects of ECS modulation and of forming possibly erroneous conclusions, extrapolated from data obtained with different drugs, whose pharmacology and effects may not be totally comparable. Both of these risks have strong implications for the interpretability and usefulness of cannabinoid research, and into the beneficial and/or deleterious potential of pharmacological manipulation of the ECS
Of adenosine and the blues: the adenosinergic system in the pathophysiology and treatment of major depressive disorder
© 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Major depressive disorder (MDD) is the foremost cause of global disability, being responsible for enormous personal, societal, and economical costs. Importantly, existing pharmacological treatments for MDD are partially or totally ineffective in a large segment of patients. As such, the search for novel antidepressant drug targets, anchored on a clear understanding of the etiological and pathophysiological mechanisms underpinning MDD, becomes of the utmost importance. The adenosinergic system, a highly conserved neuromodulatory system, appears as a promising novel target, given both its regulatory actions over many MDD-affected systems and processes. With this goal in mind, we herein review the evidence concerning the role of adenosine as a potential player in pathophysiology and treatment of MDD, combining data from both human and animal studies. Altogether, evidence supports the assertions that the adenosinergic system is altered in both MDD patients and animal models, and that drugs targeting this system have considerable potential as putative antidepressants. Furthermore, evidence also suggests that modifications in adenosine signaling may have a key role in the effects of several pharmacological and non-pharmacological antidepressant treatments with demonstrated efficacy, such as electroconvulsive shock, sleep deprivation, and deep brain stimulation. Lastly, it becomes clear from the available literature that there is yet much to study regarding the role of the adenosinergic system in the pathophysiology and treatment of MDD, and we suggest several avenues of research that are likely to prove fruitful.This work was supported by project funding from Fundação para a Ciência e para a Tecnologia (FCT) to SHV (PTDC/BTM-SAL/32147/2017) and AMS (PTDC/MED-FAR/30933/2017). This project has received funding from H2020-WIDESPREAD-05-2017-Twinning (EpiEpinet) under grant agreement No. 952455. MF-F (SFRH/BD/147505/2019), JG-R (PD/BD/150342/2019), and NR (PD/BD/113463/2015) are supported by PhD fellowships from FCT.info:eu-repo/semantics/publishedVersio
Unexpected short- and long-term effects of chronic adolescent HU-210 exposure on emotional behavior
© 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by- nc-nd/4.0/).Chronic adolescent cannabinoid receptor agonist exposure has been shown to lead to persistent increases in depressive-like behaviors. This has been a key obstacle to the development of cannabinoid-based therapeutics. However, most of the published work has been performed with only three compounds, namely Δ9-tetrahydrocannabinol, CP55,940 and WIN55,212-2. Hypothesizing that different compounds may lead to distinct outcomes, we herein used the highly potent CB1R/CB2R full agonist HU-210, and first aimed at replicating cannabinoid-induced long-lasting effects, by exposing adolescent female Sprague-Dawley rats to increasing doses of HU-210, for 11 days and testing them at adulthood, after a 30-day drug washout. Surprisingly, HU-210 did not significantly impact adult anxious- or depressive-like behaviors. We then tested whether chronic adolescent HU-210 treatment resulted in short-term (24h) alterations in depressive-like behavior. Remarkably, HU-210 treatment simultaneously induced marked antidepressant- and prodepressant-like responses, in the modified forced swim (mFST) and sucrose preference tests (SPT), respectively. Hypothesizing that mFST results were a misleading artifact of HU-210-induced behavioral hyperreactivity to stress, we assessed plasmatic noradrenaline and corticosterone levels, under basal conditions and following an acute swim-stress episode. Notably, we found that while HU-210 did not alter basal noradrenaline or corticosterone levels, it greatly augmented the stress-induced increase in both. Our results show that, contrary to previously studied cannabinoid receptor agonists, HU-210 does not induce persisting depressive-like alterations, despite inducing marked short-term increases in stress-induced reactivity. By showing that not all cannabinoid receptor agonists may induce long-term negative effects, these results hold significant relevance for the development of cannabinoid-based therapeutics.Work was supported by project funding from Fundação para a Ciência e para a Tecnologia (FCT) (PTDC/MED-FAR/30933/2017 and PTDC/MED-FAR/4834/2021) and by H2020-WIDESPREAD-05-2017-Twinning (EpiEpinet) under grant agreement No. 952455. MF-F (SFRH/BD/147505/2019), NR (PD/BD/113463/2015), JF-G (PD/BD/114441/2016) and CM-L (SFRH/BD/118238/2016) are supported by PhD fellowships from FCT. The funding sources had no involvement in study design, preparation of the manuscript, or decision regarding its submission.info:eu-repo/semantics/publishedVersio
SARS-CoV-2 introductions and early dynamics of the epidemic in Portugal
Genomic surveillance of SARS-CoV-2 in Portugal was rapidly implemented by
the National Institute of Health in the early stages of the COVID-19 epidemic, in collaboration
with more than 50 laboratories distributed nationwide.
Methods By applying recent phylodynamic models that allow integration of individual-based
travel history, we reconstructed and characterized the spatio-temporal dynamics of SARSCoV-2 introductions and early dissemination in Portugal.
Results We detected at least 277 independent SARS-CoV-2 introductions, mostly from
European countries (namely the United Kingdom, Spain, France, Italy, and Switzerland),
which were consistent with the countries with the highest connectivity with Portugal.
Although most introductions were estimated to have occurred during early March 2020, it is
likely that SARS-CoV-2 was silently circulating in Portugal throughout February, before the
first cases were confirmed.
Conclusions Here we conclude that the earlier implementation of measures could have
minimized the number of introductions and subsequent virus expansion in Portugal. This
study lays the foundation for genomic epidemiology of SARS-CoV-2 in Portugal, and highlights the need for systematic and geographically-representative genomic surveillance.We gratefully acknowledge to Sara Hill and Nuno Faria (University of Oxford) and
Joshua Quick and Nick Loman (University of Birmingham) for kindly providing us with
the initial sets of Artic Network primers for NGS; Rafael Mamede (MRamirez team,
IMM, Lisbon) for developing and sharing a bioinformatics script for sequence curation
(https://github.com/rfm-targa/BioinfUtils); Philippe Lemey (KU Leuven) for providing
guidance on the implementation of the phylodynamic models; Joshua L. Cherry
(National Center for Biotechnology Information, National Library of Medicine, National
Institutes of Health) for providing guidance with the subsampling strategies; and all
authors, originating and submitting laboratories who have contributed genome data on
GISAID (https://www.gisaid.org/) on which part of this research is based. The opinions
expressed in this article are those of the authors and do not reflect the view of the
National Institutes of Health, the Department of Health and Human Services, or the
United States government. This study is co-funded by Fundação para a Ciência e Tecnologia
and Agência de Investigação Clínica e Inovação Biomédica (234_596874175) on
behalf of the Research 4 COVID-19 call. Some infrastructural resources used in this study
come from the GenomePT project (POCI-01-0145-FEDER-022184), supported by
COMPETE 2020 - Operational Programme for Competitiveness and Internationalisation
(POCI), Lisboa Portugal Regional Operational Programme (Lisboa2020), Algarve Portugal
Regional Operational Programme (CRESC Algarve2020), under the PORTUGAL
2020 Partnership Agreement, through the European Regional Development Fund
(ERDF), and by Fundação para a Ciência e a Tecnologia (FCT).info:eu-repo/semantics/publishedVersio
Global, regional, and national disability-adjusted life-years (DALYs) for 359 diseases and injuries and healthy life expectancy (HALE) for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017.
How long one lives, how many years of life are spent in good and poor health, and how the population's state of health and leading causes of disability change over time all have implications for policy, planning, and provision of services. We comparatively assessed the patterns and trends of healthy life expectancy (HALE), which quantifies the number of years of life expected to be lived in good health, and the complementary measure of disability-adjusted life-years (DALYs), a composite measure of disease burden capturing both premature mortality and prevalence and severity of ill health, for 359 diseases and injuries for 195 countries and territories over the past 28 years. Methods We used data for age-specific mortality rates, years of life lost (YLLs) due to premature mortality, and years lived with disability (YLDs) from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 to calculate HALE and DALYs from 1990 to 2017. We calculated HALE using age-specific mortality rates and YLDs per capita for each location, age, sex, and year. We calculated DALYs for 359 causes as the sum of YLLs and YLDs. We assessed how observed HALE and DALYs differed by country and sex from expected trends based on Socio-demographic Index (SDI). We also analysed HALE by decomposing years of life gained into years spent in good health and in poor health, between 1990 and 2017, and extra years lived by females compared with males. Findings Globally, from 1990 to 2017, life expectancy at birth increased by 7·4 years (95% uncertainty interval 7·1-7·8), from 65·6 years (65·3-65·8) in 1990 to 73·0 years (72·7-73·3) in 2017. The increase in years of life varied from 5·1 years (5·0-5·3) in high SDI countries to 12·0 years (11·3-12·8) in low SDI countries. Of the additional years of life expected at birth, 26·3% (20·1-33·1) were expected to be spent in poor health in high SDI countries compared with 11·7% (8·8-15·1) in low-middle SDI countries. HALE at birth increased by 6·3 years (5·9-6·7), from 57·0 years (54·6-59·1) in 1990 to 63·3 years (60·5-65·7) in 2017. The increase varied from 3·8 years (3·4-4·1) in high SDI countries to 10·5 years (9·8-11·2) in low SDI countries. Even larger variations in HALE than these were observed between countries, ranging from 1·0 year (0·4-1·7) in Saint Vincent and the Grenadines (62·4 years [59·9-64·7] in 1990 to 63·5 years [60·9-65·8] in 2017) to 23·7 years (21·9-25·6) in Eritrea (30·7 years [28·9-32·2] in 1990 to 54·4 years [51·5-57·1] in 2017). In most countries, the increase in HALE was smaller than the increase in overall life expectancy, indicating more years lived in poor health. In 180 of 195 countries and territories, females were expected to live longer than males in 2017, with extra years lived varying from 1·4 years (0·6-2·3) in Algeria to 11·9 years (10·9-12·9) in Ukraine. Of the extra years gained, the proportion spent in poor health varied largely across countries, with less than 20% of additional years spent in poor health in Bosnia and Herzegovina, Burundi, and Slovakia, whereas in Bahrain all the extra years were spent in poor health. In 2017, the highest estimate of HALE at birth was in Singapore for both females (75·8 years [72·4-78·7]) and males (72·6 years [69·8-75·0]) and the lowest estimates were in Central African Republic (47·0 years [43·7-50·2] for females and 42·8 years [40·1-45·6] for males). Globally, in 2017, the five leading causes of DALYs were neonatal disorders, ischaemic heart disease, stroke, lower respiratory infections, and chronic obstructive pulmonary disease. Between 1990 and 2017, age-standardised DALY rates decreased by 41·3% (38·8-43·5) for communicable diseases and by 49·8% (47·9-51·6) for neonatal disorders. For non-communicable diseases, global DALYs increased by 40·1% (36·8-43·0), although age-standardised DALY rates decreased by 18·1% (16·0-20·2)
Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019
Background: In an era of shifting global agendas and expanded emphasis on non-communicable diseases and injuries along with communicable diseases, sound evidence on trends by cause at the national level is essential. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) provides a systematic scientific assessment of published, publicly available, and contributed data on incidence, prevalence, and mortality for a mutually exclusive and collectively exhaustive list of diseases and injuries. Methods: GBD estimates incidence, prevalence, mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) due to 369 diseases and injuries, for two sexes, and for 204 countries and territories. Input data were extracted from censuses, household surveys, civil registration and vital statistics, disease registries, health service use, air pollution monitors, satellite imaging, disease notifications, and other sources. Cause-specific death rates and cause fractions were calculated using the Cause of Death Ensemble model and spatiotemporal Gaussian process regression. Cause-specific deaths were adjusted to match the total all-cause deaths calculated as part of the GBD population, fertility, and mortality estimates. Deaths were multiplied by standard life expectancy at each age to calculate YLLs. A Bayesian meta-regression modelling tool, DisMod-MR 2.1, was used to ensure consistency between incidence, prevalence, remission, excess mortality, and cause-specific mortality for most causes. Prevalence estimates were multiplied by disability weights for mutually exclusive sequelae of diseases and injuries to calculate YLDs. We considered results in the context of the Socio-demographic Index (SDI), a composite indicator of income per capita, years of schooling, and fertility rate in females younger than 25 years. Uncertainty intervals (UIs) were generated for every metric using the 25th and 975th ordered 1000 draw values of the posterior distribution. Findings: Global health has steadily improved over the past 30 years as measured by age-standardised DALY rates. After taking into account population growth and ageing, the absolute number of DALYs has remained stable. Since 2010, the pace of decline in global age-standardised DALY rates has accelerated in age groups younger than 50 years compared with the 1990–2010 time period, with the greatest annualised rate of decline occurring in the 0–9-year age group. Six infectious diseases were among the top ten causes of DALYs in children younger than 10 years in 2019: lower respiratory infections (ranked second), diarrhoeal diseases (third), malaria (fifth), meningitis (sixth), whooping cough (ninth), and sexually transmitted infections (which, in this age group, is fully accounted for by congenital syphilis; ranked tenth). In adolescents aged 10–24 years, three injury causes were among the top causes of DALYs: road injuries (ranked first), self-harm (third), and interpersonal violence (fifth). Five of the causes that were in the top ten for ages 10–24 years were also in the top ten in the 25–49-year age group: road injuries (ranked first), HIV/AIDS (second), low back pain (fourth), headache disorders (fifth), and depressive disorders (sixth). In 2019, ischaemic heart disease and stroke were the top-ranked causes of DALYs in both the 50–74-year and 75-years-and-older age groups. Since 1990, there has been a marked shift towards a greater proportion of burden due to YLDs from non-communicable diseases and injuries. In 2019, there were 11 countries where non-communicable disease and injury YLDs constituted more than half of all disease burden. Decreases in age-standardised DALY rates have accelerated over the past decade in countries at the lower end of the SDI range, while improvements have started to stagnate or even reverse in countries with higher SDI. Interpretation: As disability becomes an increasingly large component of disease burden and a larger component of health expenditure, greater research and developm nt investment is needed to identify new, more effective intervention strategies. With a rapidly ageing global population, the demands on health services to deal with disabling outcomes, which increase with age, will require policy makers to anticipate these changes. The mix of universal and more geographically specific influences on health reinforces the need for regular reporting on population health in detail and by underlying cause to help decision makers to identify success stories of disease control to emulate, as well as opportunities to improve. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens
Global age-sex-specific fertility, mortality, healthy life expectancy (HALE), and population estimates in 204 countries and territories, 1950-2019 : a comprehensive demographic analysis for the Global Burden of Disease Study 2019
Background: Accurate and up-to-date assessment of demographic metrics is crucial for understanding a wide range of social, economic, and public health issues that affect populations worldwide. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 produced updated and comprehensive demographic assessments of the key indicators of fertility, mortality, migration, and population for 204 countries and territories and selected subnational locations from 1950 to 2019.
Methods: 8078 country-years of vital registration and sample registration data, 938 surveys, 349 censuses, and 238 other sources were identified and used to estimate age-specific fertility. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate age-specific fertility rates for 5-year age groups between ages 15 and 49 years. With extensions to age groups 10–14 and 50–54 years, the total fertility rate (TFR) was then aggregated using the estimated age-specific fertility between ages 10 and 54 years. 7417 sources were used for under-5 mortality estimation and 7355 for adult mortality. ST-GPR was used to synthesise data sources after correction for known biases. Adult mortality was measured as the probability of death between ages 15 and 60 years based on vital registration, sample registration, and sibling histories, and was also estimated using ST-GPR. HIV-free life tables were then estimated using estimates of under-5 and adult mortality rates using a relational model life table system created for GBD, which closely tracks observed age-specific mortality rates from complete vital registration when available. Independent estimates of HIV-specific mortality generated by an epidemiological analysis of HIV prevalence surveys and antenatal clinic serosurveillance and other sources were incorporated into the estimates in countries with large epidemics. Annual and single-year age estimates of net migration and population for each country and territory were generated using a Bayesian hierarchical cohort component model that analysed estimated age-specific fertility and mortality rates along with 1250 censuses and 747 population registry years. We classified location-years into seven categories on the basis of the natural rate of increase in population (calculated by subtracting the crude death rate from the crude birth rate) and the net migration rate. We computed healthy life expectancy (HALE) using years lived with disability (YLDs) per capita, life tables, and standard demographic methods. Uncertainty was propagated throughout the demographic estimation process, including fertility, mortality, and population, with 1000 draw-level estimates produced for each metric. Findings: The global TFR decreased from 2·72 (95% uncertainty interval [UI] 2·66–2·79) in 2000 to 2·31 (2·17–2·46) in 2019. Global annual livebirths increased from 134·5 million (131·5–137·8) in 2000 to a peak of 139·6 million (133·0–146·9) in 2016. Global livebirths then declined to 135·3 million (127·2–144·1) in 2019. Of the 204 countries and territories included in this study, in 2019, 102 had a TFR lower than 2·1, which is considered a good approximation of replacement-level fertility. All countries in sub-Saharan Africa had TFRs above replacement level in 2019 and accounted for 27·1% (95% UI 26·4–27·8) of global livebirths. Global life expectancy at birth increased from 67·2 years (95% UI 66·8–67·6) in 2000 to 73·5 years (72·8–74·3) in 2019. The total number of deaths increased from 50·7 million (49·5–51·9) in 2000 to 56·5 million (53·7–59·2) in 2019. Under-5 deaths declined from 9·6 million (9·1–10·3) in 2000 to 5·0 million (4·3–6·0) in 2019. Global population increased by 25·7%, from 6·2 billion (6·0–6·3) in 2000 to 7·7 billion (7·5–8·0) in 2019. In 2019, 34 countries had negative natural rates of increase; in 17 of these, the population declined because immigration was not sufficient to counteract the negative rate of decline. Globally, HALE increased from 58·6 years (56·1–60·8) in 2000 to 63·5 years (60·8–66·1) in 2019. HALE increased in 202 of 204 countries and territories between 2000 and 2019
Global, regional, and national disability-adjusted life-years (DALYs) for 359 diseases and injuries and healthy life expectancy (HALE) for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017
How long one lives, how many years of life are spent in good and poor health, and how the population's state of health and leading causes of disability change over time all have implications for policy, planning, and provision of services. We comparatively assessed the patterns and trends of healthy life expectancy (HALE), which quantifies the number of years of life expected to be lived in good health, and the complementary measure of disability-adjusted life-years (DALYs), a composite measure of disease burden capturing both premature mortality and prevalence and severity of ill health, for 359 diseases and injuries for 195 countries and territories over the past 28 years.; We used data for age-specific mortality rates, years of life lost (YLLs) due to premature mortality, and years lived with disability (YLDs) from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 to calculate HALE and DALYs from 1990 to 2017. We calculated HALE using age-specific mortality rates and YLDs per capita for each location, age, sex, and year. We calculated DALYs for 359 causes as the sum of YLLs and YLDs. We assessed how observed HALE and DALYs differed by country and sex from expected trends based on Socio-demographic Index (SDI). We also analysed HALE by decomposing years of life gained into years spent in good health and in poor health, between 1990 and 2017, and extra years lived by females compared with males. Globally, from 1990 to 2017, life expectancy at birth increased by 7·4 years (95% uncertainty interval 7·1-7·8), from 65·6 years (65·3-65·8) in 1990 to 73·0 years (72·7-73·3) in 2017. The increase in years of life varied from 5·1 years (5·0-5·3) in high SDI countries to 12·0 years (11·3-12·8) in low SDI countries. Of the additional years of life expected at birth, 26·3% (20·1-33·1) were expected to be spent in poor health in high SDI countries compared with 11·7% (8·8-15·1) in low-middle SDI countries. HALE at birth increased by 6·3 years (5·9-6·7), from 57·0 years (54·6-59·1) in 1990 to 63·3 years (60·5-65·7) in 2017. The increase varied from 3·8 years (3·4-4·1) in high SDI countries to 10·5 years (9·8-11·2) in low SDI countries. Even larger variations in HALE than these were observed between countries, ranging from 1·0 year (0·4-1·7) in Saint Vincent and the Grenadines (62·4 years [59·9-64·7] in 1990 to 63·5 years [60·9-65·8] in 2017) to 23·7 years (21·9-25·6) in Eritrea (30·7 years [28·9-32·2] in 1990 to 54·4 years [51·5-57·1] in 2017). In most countries, the increase in HALE was smaller than the increase in overall life expectancy, indicating more years lived in poor health. In 180 of 195 countries and territories, females were expected to live longer than males in 2017, with extra years lived varying from 1·4 years (0·6-2·3) in Algeria to 11·9 years (10·9-12·9) in Ukraine. Of the extra years gained, the proportion spent in poor health varied largely across countries, with less than 20% of additional years spent in poor health in Bosnia and Herzegovina, Burundi, and Slovakia, whereas in Bahrain all the extra years were spent in poor health. In 2017, the highest estimate of HALE at birth was in Singapore for both females (75·8 years [72·4-78·7]) and males (72·6 years [69·8-75·0]) and the lowest estimates were in Central African Republic (47·0 years [43·7-50·2] for females and 42·8 years [40·1-45·6] for males). Globally, in 2017, the five leading causes of DALYs were neonatal disorders, ischaemic heart disease, stroke, lower respiratory infections, and chronic obstructive pulmonary disease. Between 1990 and 2017, age-standardised DALY rates decreased by 41·3% (38·8-43·5) for communicable diseases and by 49·8% (47·9-51·6) for neonatal disorders. For non-communicable diseases, global DALYs increased by 40·1% (36·8-43·0), although age-standardised DALY rates decreased by 18·1% (16·0-20·2). With increasing life expectancy in most countries, the question of whether the additional years of life gained are spent in good health or poor health has been increasingly relevant because of the potential policy implications, such as health-care provisions and extending retirement ages. In some locations, a large proportion of those additional years are spent in poor health. Large inequalities in HALE and disease burden exist across countries in different SDI quintiles and between sexes. The burden of disabling conditions has serious implications for health system planning and health-related expenditures. Despite the progress made in reducing the burden of communicable diseases and neonatal disorders in low SDI countries, the speed of this progress could be increased by scaling up proven interventions. The global trends among non-communicable diseases indicate that more effort is needed to maximise HALE, such as risk prevention and attention to upstream determinants of health