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. Interpretation: Over the past 20 years, fertility rates have been dropping steadily and life expectancy has been increasing, with few exceptions. Much of this change follows historical patterns linking social and economic determinants, such as those captured by the GBD Socio-demographic Index, with demographic outcomes. More recently, several countries have experienced a combination of low fertility and stagnating improvement in mortality rates, pushing more populations into the late stages of the demographic transition. Tracking demographic change and the emergence of new patterns will be essential for global health monitoring. 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 burden of 87 risk factors in 204 countries and territories, 1990�2019: a systematic analysis for the Global Burden of Disease Study 2019

Background: Rigorous analysis of levels and trends in exposure to leading risk factors and quantification of their effect on human health are important to identify where public health is making progress and in which cases current efforts are inadequate. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 provides a standardised and comprehensive assessment of the magnitude of risk factor exposure, relative risk, and attributable burden of disease. Methods: GBD 2019 estimated attributable mortality, years of life lost (YLLs), years of life lived with disability (YLDs), and disability-adjusted life-years (DALYs) for 87 risk factors and combinations of risk factors, at the global level, regionally, and for 204 countries and territories. GBD uses a hierarchical list of risk factors so that specific risk factors (eg, sodium intake), and related aggregates (eg, diet quality), are both evaluated. This method has six analytical steps. (1) We included 560 risk�outcome pairs that met criteria for convincing or probable evidence on the basis of research studies. 12 risk�outcome pairs included in GBD 2017 no longer met inclusion criteria and 47 risk�outcome pairs for risks already included in GBD 2017 were added based on new evidence. (2) Relative risks were estimated as a function of exposure based on published systematic reviews, 81 systematic reviews done for GBD 2019, and meta-regression. (3) Levels of exposure in each age-sex-location-year included in the study were estimated based on all available data sources using spatiotemporal Gaussian process regression, DisMod-MR 2.1, a Bayesian meta-regression method, or alternative methods. (4) We determined, from published trials or cohort studies, the level of exposure associated with minimum risk, called the theoretical minimum risk exposure level. (5) Attributable deaths, YLLs, YLDs, and DALYs were computed by multiplying population attributable fractions (PAFs) by the relevant outcome quantity for each age-sex-location-year. (6) PAFs and attributable burden for combinations of risk factors were estimated taking into account mediation of different risk factors through other risk factors. Across all six analytical steps, 30 652 distinct data sources were used in the analysis. Uncertainty in each step of the analysis was propagated into the final estimates of attributable burden. Exposure levels for dichotomous, polytomous, and continuous risk factors were summarised with use of the summary exposure value to facilitate comparisons over time, across location, and across risks. Because the entire time series from 1990 to 2019 has been re-estimated with use of consistent data and methods, these results supersede previously published GBD estimates of attributable burden. Findings: The largest declines in risk exposure from 2010 to 2019 were among a set of risks that are strongly linked to social and economic development, including household air pollution; unsafe water, sanitation, and handwashing; and child growth failure. Global declines also occurred for tobacco smoking and lead exposure. The largest increases in risk exposure were for ambient particulate matter pollution, drug use, high fasting plasma glucose, and high body-mass index. In 2019, the leading Level 2 risk factor globally for attributable deaths was high systolic blood pressure, which accounted for 10·8 million (95 uncertainty interval UI 9·51�12·1) deaths (19·2% 16·9�21·3 of all deaths in 2019), followed by tobacco (smoked, second-hand, and chewing), which accounted for 8·71 million (8·12�9·31) deaths (15·4% 14·6�16·2 of all deaths in 2019). The leading Level 2 risk factor for attributable DALYs globally in 2019 was child and maternal malnutrition, which largely affects health in the youngest age groups and accounted for 295 million (253�350) DALYs (11·6% 10·3�13·1 of all global DALYs that year). The risk factor burden varied considerably in 2019 between age groups and locations. Among children aged 0�9 years, the three leading detailed risk factors for attributable DALYs were all related to malnutrition. Iron deficiency was the leading risk factor for those aged 10�24 years, alcohol use for those aged 25�49 years, and high systolic blood pressure for those aged 50�74 years and 75 years and older. Interpretation: Overall, the record for reducing exposure to harmful risks over the past three decades is poor. Success with reducing smoking and lead exposure through regulatory policy might point the way for a stronger role for public policy on other risks in addition to continued efforts to provide information on risk factor harm to the general public. 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

Reducing sediment inputs to Scottish streams: a review of the efficacy of soil conservation practices in upland forestry

The historical process by which a soil conservation strategy has evolved within the UK forestry industry is briefly reviewed. Particular attention is given to the development of practical and effective guidelines to prevent both soil damage and sediment entering water courses. It is concluded that the ‘Forest and Water Guidelines’, together with other forest industry manuals, largely provide adequate protection for aquatic habitats from pre-afforestation cultivation and from harvesting activities. The problem of soil erosion owing to ploughing of open furrows has largely been obviated by improved drainage network design coupled with the use of vegetated buffer strips and sediment catchpits. Alternative site preparation techniques, such as ‘moling’ or ‘dolloping’ of afforestation sites, are now preferred. However, the effects on slope hydrology and the improved soil conservation associated with these methods require quantifying. Additional understanding of effective buffer strip function, for example, on a variety of slope angles, soil types and vegetation associations would be beneficial. The design of forest roads and the associated network of drains, culverts and sediment catchpits is addressed in forestry guidelines. Future potential in this area may involve the use of Geographical Information Systems in the effective design of road networks which minimise adverse effects on slope hydrology. Similarly computer simulation of flow routing might aid in the design of road drain networks. At the more local scale there remains scope for further research aimed at minimising soil disturbance by machinery. Consideration should also be given to the long-term sustainability of the soil structure through second and subsequent crop rotations. <br/

Red deer behavioural response to hiking activity: a study using camera traps

With increasing levels of outdoor recreation activities, consequences for wildlife through interactions with recreationists are highly variable. Behavioural changes in wildlife are one potential consequence of interactions with outdoor recreationists. In ungulate populations, vigilance and flight responses are well-known antipredator behaviours. An increase in their level indicates a more intense stress level which, ultimately, can have consequences for animal fitness. In Scotland, the geographical distribution of red deer (Cervus elaphus) overlaps greatly with areas used for popular outdoor activities such as hill walking. In this research, we study red deer time allocation, vigilance, and flight behaviours near a popular hiking path using camera traps. We positioned the cameras in transects at different distances (25m, 75m and 150m) from the path and recorded hiking activity using an automated people counter. Red deer behaviour was categorized from photo analysis as (1) no response (e.g., feeding, resting), (2) vigilant (i.e., upright head position), and (3) flight response. We also investigated demographic variables (group size, sex) and the direction of red deer movement relative to the trail. We used generalised linear mixed models to analyse behaviour in relation to the distance from the hiking track, hiking activity, time of the day, demographic, and environmental variables. We did not find an increase in vigilance or flight behaviour in relation to the distance from the hiking path or the hiking activity. These results suggest that red deer, in our study area, are habituated to the presence of hikers and may spatially avoid areas close to the hiking path instead of displaying cost-intensive behaviour (i.e., flight or vigilance behaviour)

Red deer exhibit spatial and temporal responses to hiking activity

Outdoor recreation has the potential to impact the spatial and temporal distribution of animals. We explore interactions between red deer (Cervus elaphus) and hikers along a popular hiking path in the Scottish Highlands. We placed camera traps in transects at different distances (25, 75 and 150 metres) from the path to study whether distance from hiker activity influences the number of deer detected. We compared this with the detection of red deer in an additional, spatially isolated area (one km away from any other transects and the hiking path). We collected count data on hikers at the start of the path and explored hourly (red deer detection during daytime), daily, diurnal (day vs night), and monthly spatial distributions of red deer. Using Generalized Linear Mixed Models with forward model selection, we found that the distribution of deer changed with the hiking activity. We found that fewer red deer were detected during busy hourly hiking periods. We found that during daytime, more red deer were detected at 150m than at 25m. Moreover, during the day, red deer were detected at a greater rate in the isolated area than around the transects close to the path and more likely to be found close to the path at night. This suggests that avoidance of hikers by red deer, in this study area, takes place over distances greater than 75m and that red deer are displaced into less disturbed areas when the hiking path is busy. Our results suggest that the impact of hikers is short-term, as deer return to the disturbed areas during the night

Spatial and temporal variation in interspecific interaction: impact of a recreational landscape

Anthropogenic activities, such as outdoor recreation, have the potential to change complex interactions between wildlife and livestock, with further consequences for the management of both animals, the environment, and disease transmission. We present the interaction amongst wildlife, livestock, and outdoor recreationists as a three-way interaction. Little is known about how recreational activities alter the interaction between herbivores in areas extensively used of recreational purposes. We investigate how hiking activity affects spatio-temporal co-occurrence between domestic sheep (Ovis aries) and red deer (Cervus elaphus). We used camera traps to capture the spatio-temporal distribution of red deer and sheep at varying distances from a popular hiking trail. We used the distance from the hiking path as a proxy of hiking activity. We used generalized linear models to investigate the spatial distribution of sheep and deer. We analysed the activity patterns of sheep and deer and then calculated their coefficients of temporal overlap for each camera trap location using a non-parametric kernel density estimation method. We compared these coefficients in relation to the distance from the hiking path. Finally, we used a generalized linear mixed-model to investigate which factors influence the spatio-temporal succession between deer and sheep. We do not find that sheep and red deer spatially avoid each other, but we did find that sheep temporally avoid red deer, while red deer do not appear to temporally avoid sheep. The coefficient of temporal overlap varied with distance from the hiking trail, with stronger temporal co-occurrence at greater distances from the hiking trail. Red deer were more likely to be detected further from the path during the day, which increased the temporal overlap with sheep in these areas. This suggests that hiking pressure influences spatio-temporal interactions between sheep and deer, leading to greater temporal overlap in areas further from the hiking path due to red deer spatial avoidance of hikers. This impact of recreationists on the wildlife – livestock interaction can have consequences for the animals’ welfare, the vegetation they graze, their management and disease transmission

Randomized trial of laparoscopic nissen vs. anterior 180 degree partial fundoplication - late clinical outcomes at 15-20 years

OBJECTIVE:To determine very late clinical outcomes at up to 20 years follow-up from a randomized controlled trial of Nissen vs. anterior 180-degree partial fundoplication. SUMMARY BACKGROUND DATA:Nissen fundoplication for gastroesophageal reflux can be followed by troublesome side effects. To address this, partial fundoplications have been proposed. Previously reports from a randomized controlled trial of Nissen vs. anterior 180-degree partial fundoplication at up to 10 years follow-up showed good outcomes for both procedures. METHODS:107 participants were randomized to Nissen vs. anterior 180-degree partial fundoplication. 15-20 year follow-up data was available for 79 (41 Nissen, 38 anterior). Outcome was assessed using a standardized questionnaire with 0-10 analogue scores and yes/no questions to determine reflux symptoms, side-effects and satisfaction with surgery. RESULTS:After anterior fundoplication heartburn (mean score 3.2 vs 1.4, p = 0.001) and proton pump inhibitor use (41.7% vs 17.1%, p = 0.023) were higher, offset by less dysphagia for solids (mean score 1.8 vs 3.3, p = 0.015), and better ability to belch (84.2% vs 65.9%, p = 0.030). Measures of overall outcome were similar for both groups (mean satisfaction score 8.4 vs 8.0, p = 0.444; 86.8% vs 90.2% satisfied with outcome). Six participants underwent revision following anterior fundoplication (Nissen conversion for reflux - 6), and 7 underwent revision following Nissen fundoplication (Nissen to partial fundoplication for dysphagia - 5; redo Nissen for reflux - 1; paraesophageal hernia -1). CONCLUSIONS:At 15-20 years follow-up Nissen and anterior 180-degree partial fundoplication achieved similar success, but with trade-offs between better reflux control vs. more side-effects after Nissen fundoplication.Victoria Rudolph-Stringer, Tim Bright, Tanya Irvine, Sarah K. Thompson, Peter G. Devitt, Glyn G. Jamieson, David I. Watson ... et al

Five year follow-up of a randomized controlled trial of laparoscopic repair of very large hiatus hernia with sutures versus absorbable versus nonabsorbable mesh

OBJECTIVE:To determine whether absorbable or nonabsorbable mesh repair of large hiatus hernias is followed by less recurrences at late follow-up compared to sutured repair. SUMMARY OF BACKGROUND DATA:Radiological recurrences have been reported in up to 30% of patients after repair of large hiatus hernias, and mesh repair has been proposed as a solution. Earlier trials have revealed mixed outcomes and early outcomes from a trial reported previously revealed no short-term advantages for mesh repair. METHODS:Multicentre prospective double-blind randomized controlled trial of 3 methods of hiatus hernia repair; sutures versus absorbable mesh versus nonabsorbable mesh. Primary outcome - hernia recurrence assessed by barium meal X-ray and endoscopy at 3-4 years. Secondary outcomes - clinical symptom scores at 2, 3, and 5 years. RESULTS:126 patients were enrolled - 43 sutures, 41 absorbable mesh, and 42 nonabsorbable mesh. Clinical outcomes were obtained at 5 years in 89.9%, and objective follow-up was obtained in 72.3%. A recurrent hernia (any size) was identified in 39.3% after suture repair, 56.7% - absorbable mesh, and 42.9% - nonabsorbable mesh (P = 0.371). Clinical outcomes were similar at 5 years, except chest pain, diarrhea, and bloat symptoms which were more common after repair with absorbable mesh. CONCLUSIONS:No advantages were demonstrated for mesh repair at up to 5 years follow-up, and symptom outcomes were worse after repair with absorbable mesh. The longer-term results from this trial do not support mesh repair for large hiatus hernias.David I. Watson, Sarah K. Thompson, Peter G. Devitt, Ahmad Aly, Tanya Irvine, Simon D. Woods ... et al