Identifying dementia outcomes in UK Biobank Wilkinson, Tim; Schnier, Christian; Bush, Kathryn ...
European journal of epidemiology,
06/2019, Letnik:
34, Številka:
6
Journal Article
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Prospective, population-based studies that recruit participants in mid-life are valuable resources for dementia research. Follow-up in these studies is often through linkage to routinely-collected ...healthcare datasets. We investigated the accuracy of these datasets for dementia case ascertainment in a validation study using data from UK Biobank—an open access, population-based study of > 500,000 adults aged 40–69 years at recruitment in 2006–2010. From 17,198 UK Biobank participants recruited in Edinburgh, we identified those with ≥ 1 dementia code in their linked primary care, hospital admissions or mortality data and compared their coded diagnoses to clinical expert adjudication of their full-text medical record. We calculated the positive predictive value (PPV, the proportion of cases identified that were true positives) for all-cause dementia, Alzheimer’s disease and vascular dementia for each dataset alone and in combination, and explored algorithmic code combinations to improve PPV. Among 120 participants, PPVs for all-cause dementia were 86.8%, 87.3% and 80.0% for primary care, hospital admissions and mortality data respectively and 82.5% across all datasets. We identified three algorithms that balanced a high PPV with reasonable case ascertainment. For Alzheimer’s disease, PPVs were 74.1% for primary care, 68.2% for hospital admissions, 50.0% for mortality data and 71.4% in combination. PPV for vascular dementia was 43.8% across all sources. UK routinely-collected healthcare data can be used to identify all-cause dementia in prospective studies. PPVs for Alzheimer’s disease and vascular dementia are lower. Further research is required to explore the geographic generalisability of these findings.
Earth's forests face grave challenges in the Anthropocene, including hotter droughts increasingly associated with widespread forest die-off events. But despite the vital importance of forests to ...global ecosystem services, their fates in a warming world remain highly uncertain. Lacking is quantitative determination of commonality in climate anomalies associated with pulses of tree mortality-from published, field-documented mortality events-required for understanding the role of extreme climate events in overall global tree die-off patterns. Here we established a geo-referenced global database documenting climate-induced mortality events spanning all tree-supporting biomes and continents, from 154 peer-reviewed studies since 1970. Our analysis quantifies a global "hotter-drought fingerprint" from these tree-mortality sites-effectively a hotter and drier climate signal for tree mortality-across 675 locations encompassing 1,303 plots. Frequency of these observed mortality-year climate conditions strongly increases nonlinearly under projected warming. Our database also provides initial footing for further community-developed, quantitative, ground-based monitoring of global tree mortality.
In this study we compared 3.7 million rawinsonde observations from 232 stations over Europe and North America with proximal vertical profiles from ERA5 and MERRA-2 to examine how well reanalysis ...depicts observed convective parameters. Larger differences between soundings and reanalysis are found for thermodynamic theoretical parcel parameters, low-level lapse rates, and low-level wind shear. In contrast, reanalysis best represents temperature and moisture variables, mid-tropospheric lapse rates, and mean wind. Both reanalyses underestimate CAPE, low-level moisture, and wind shear, particularly when considering extreme values. Overestimation is observed for low-level lapse rates, midtropospheric moisture, and the level of free convection. Mixed-layer parcels have overall better accuracy when compared to most-unstable parcels, especially considering convective inhibition and lifted condensation level. Mean absolute error for both reanalyses has been steadily decreasing over the last 39 years for almost every analyzed variable. Compared to MERRA-2, ERA5 has higher correlations and lower mean absolute errors. MERRA-2 is typically drier and less unstable over central Europe and the Balkans, with the opposite pattern over western Russia. Both reanalyses underestimate CAPE and CIN over the Great Plains. Reanalyses are more reliable for lower elevation stations and struggle along boundaries such as coastal zones and mountains. Based on the results from this and prior studies we suggest that ERA5 is likely one of the most reliable available reanalyses for exploration of convective environments, mainly due to its improved resolution. For future studies we also recommend that computation of convective variables should use model levels that provide more accurate sampling of the boundary layer conditions compared to less numerous pressure levels.
In this study we investigate convective environments and their corresponding climatological features over Europe and the United States. For this purpose, National Lightning Detection Network (NLDN) ...and Arrival Time Difference long-range lightning detection network (ATDnet) data, ERA5 hybrid-sigma levels, and severe weather reports from the European Severe Weather Database (ESWD) and Storm Prediction Center (SPC) Storm Data were combined on a common grid of 0.25° and 1-h steps over the period 1979–2018. The severity of convective hazards increases with increasing instability and wind shear (WMAXSHEAR), but climatological aspects of these features differ over both domains. Environments over the United States are characterized by higher moisture, CAPE, CIN, wind shear, and midtropospheric lapse rates. Conversely, 0–3-km CAPE and low-level lapse rates are higher over Europe. From the climatological perspective severe thunderstorm environments (hours) are around 3–4 times more frequent over the United States with peaks across the Great Plains, Midwest, and Southeast. Over Europe severe environments are the most common over the south with local maxima in northern Italy. Despite having lower CAPE (tail distribution of 3000–4000 J kg−1 compared to 6000–8000 J kg−1 over the United States), thunderstorms over Europe have a higher probability for convective initiation given a favorable environment. Conversely, the lowest probability for initiation is observed over the Great Plains, but, once a thunderstorm develops, the probability that it will become severe is much higher compared to Europe. Prime conditions for severe thunderstorms over the United States are between April and June, typically from 1200 to 2200 central standard time (CST), while across Europe favorable environments are observed from June to August, usually between 1400 and 2100 UTC.
This paper describes the development and analysis of an objective climatology of warm and cold fronts over North America from 1979 to 2018. Fronts are detected by a convolutional neural network ...(CNN), trained to emulate fronts drawn by human meteorologists. Predictors for the CNN are surface and 850-hPa fields of temperature, specific humidity, and vector wind from the ERA5 reanalysis. Gridded probabilities from the CNN are converted to 2D frontal regions, which are used to create the climatology. Overall, warm and cold fronts are most common in the Pacific and Atlantic cyclone tracks and the lee of the Rockies. In contrast with prior research, we find that the activity of warm and cold fronts is significantly modulated by the phase and intensity of El Niño–Southern Oscillation. The influence of El Niño is significant for winter warm fronts, winter cold fronts, and spring cold fronts, with activity decreasing over the continental United States and shifting northward with the Pacific and Atlantic cyclone tracks. Long-term trends are generally not significant, although we find a poleward shift in frontal activity during the winter and spring, consistent with prior research. We also identify a number of regional patterns, such as a significant long-term increase in warm fronts in the eastern tropical Pacific Ocean, which are characterized almost entirely by moisture gradients rather than temperature gradients.
Long-term trends in the historical frequency of environments supportive of atmospheric convection are unclear, and only partially follow the expectations of a warming climate. This uncertainty is ...driven by the lack of unequivocal changes in the ingredients for severe thunderstorms (i.e., conditional instability, sufficient low-level moisture, initiation mechanism, and vertical wind shear). ERA5 hybrid-sigma data allow for superior characterization of thermodynamic parameters including convective inhibition, which is very sensitive to the number of levels in the lower troposphere. Using hourly data we demonstrate that long-term decreases in instability and stronger convective inhibition cause a decline in the frequency of thunderstorm environments over the southern United States, particularly during summer. Conversely, increasingly favorable conditions for tornadoes are observed during winter across the Southeast. Over Europe, a pronounced multidecadal increase in low-level moisture has provided positive trends in thunderstorm environments over the south, central, and north, with decreases over the east due to strengthening convective inhibition. Modest increases in vertical wind shear and storm-relative helicity have been observed over northwestern Europe and the Great Plains. Both continents exhibit negative trends in the fraction of environments with likely convective initiation. This suggests that despite increasing instability, thunderstorms in a warming climate may be less likely to develop due to stronger convective inhibition and lower relative humidity. Decreases in convective initiation and resulting precipitation may have long-term implications for agriculture, water availability, and the frequency of severe weather such as large hail and tornadoes. Our results also indicate that trends observed over the United States cannot be assumed to be representative of other continents.
Life expectancy in the US is now the lowest it has been since 1996, with young- and middle-aged adults seeing the most rapid declines. These declines began in 2014 and have accelerated over the past ...3 years of the pandemic. While COVID-19 represents a significant proportion, increases in heart disease between 2020 and 2021 explain more than 4% of the most recent shortening in life expectancy. These increases in cardiovascular mortality reflect recent disturbing trends in cardiovascular risk determinants and events in younger adults. Although overall cardiovascular disease mortality declined until 2020, hospitalization and death rates flattened or in some cases increased among specific racial and ethnic subgroups of young adults during this time. In particular, hypertensive heart disease, heart failure, and endocarditis have increased in young adults, particularly among Black individuals, through 2018.7 Consequently, young adults make up a growing proportion of cardiovascular disease events, with the proportion of premature myocardial infarction among adults younger than 40 years increasing by 2% every year. The increasing event rates observed among younger adults can be attributed to the increasing prevalence and onset of risk factors such as obesity and hypertension at younger ages, which exacerbate cumulative exposure and cardiovascular disease risk over near- and long-term time horizons.
Tornadic thunderstorms rely on the availability of sufficient low-level moisture, but the source regions of that moisture have not been explicitly demarcated. Using the NOAA Air Resources Laboratory ...HYSPLIT model and a Lagrangian-based diagnostic, moisture attribution was conducted to identify the moisture source regions of tornadic convection. This study reveals a seasonal cycle in the origins and advection patterns of water vapor contributing to winter and spring tornado-producing storms (1981–2017). The Gulf of Mexico is shown to be the predominant source of moisture during both winter and spring, making up more than 50% of all contributions. During winter, substantial moisture contributions for tornadic convection also emanate from the western Caribbean Sea (>19%) and North Atlantic Ocean (>12%). During late spring, land areas (e.g., soil and vegetation) of the contiguous United States (CONUS) play a more influential role (>24%). Moisture attribution was also conducted for nontornadic cases and tornado outbreaks. Findings show that moisture sources of nontornadic events are more proximal to the CONUS than moisture sources of tornado outbreaks. Oceanic influences on the water vapor content of air parcels were also explored to determine if they can increase the likelihood of an air mass attaining moisture that will eventually contribute to severe thunderstorms. Warmer sea surface temperatures were generally found to enhance evaporative fluxes of overlying air parcels. The influence of atmospheric features on synoptic-scale moisture advection was also analyzed; stronger extratropical cyclones and Great Plains low-level jet occurrences lead to increased meridional moisture flux.
ABSTRACT
Severe thunderstorms present a significant threat to property and life in Australia during the warm season (September to April). However, these relatively infrequent events are poorly ...understood in terms of frequency and occurrence for much of the continent due to a lack of in‐situ observations. With the spectre of a changing climate, there is an increasing need to understand thunderstorms and their impact on Australia, both in the past and for the future. To facilitate this, the relationship between severe thunderstorms and their associated environments is used as a probabilistic proxy for direct observations. To establish these conditions, a proximity climatology of environments was developed for observed severe thunderstorms in Australia during the period 2003–2010 using the ERA‐Interim reanalysis. Proximity soundings from the reanalysis for observed severe thunderstorms were used to develop covariate discriminants that identify the increased probability of an environment to produce severe thunderstorms. The covariates use a combination of ingredients describing instability (mixed‐layer convective available potential energy) and potential for organized severe convection (deep‐layer wind shear). These discriminants have been extrapolated to produce a climatology of environments favourable to the development of severe thunderstorms over the period 1979–2011 from this reanalysis. The inter‐annual variations in both the spatial and temporal distribution of convective environments over Australia were analysed, with particular focus on the influence of El Niño‐Southern Oscillation (ENSO) on the occurrence of severe thunderstorm environments. These results suggest that while ENSO has a substantial impact on the spatial distribution of severe thunderstorm environments over the continent, the link to frequency is more uncertain.
IMPORTANCE Single measures of blood pressure (BP) levels are associated with the development of atherosclerosis; however, long-term patterns in BP and their effect on cardiovascular disease risk are ...poorly characterized. OBJECTIVES To identify common BP trajectories throughout early adulthood and to determine their association with presence of coronary artery calcification (CAC) during middle age. DESIGN, SETTING, AND PARTICIPANTS Prospective cohort data from 4681 participants in the CARDIA study, who were black and white men and women aged 18 to 30 years at baseline in 1985-1986 at 4 urban US sites, collected through 25 years of follow-up (2010-2011). We examined systolic BP, diastolic BP, and mid-BP (calculated as SBP+DBP/2, an important marker of coronary heart disease risk among younger populations) at baseline and years 2, 5, 7, 10, 15, 20, and 25. Latent mixture modeling was used to identify trajectories in systolic, diastolic, and mid-BP over time. MAIN OUTCOMES AND MEASURES Coronary artery calcification greater than or equal to Agatston score of 100 Hounsfield units (HU) at year 25. RESULTS We identified 5 distinct mid-BP trajectories: low-stable (21.8%; 95% CI, 19.9%-23.7%; n=987), moderate-stable (42.3%; 40.3%-44.3%; n=2085), moderate-increasing (12.2%; 10.4%-14.0%; n=489), elevated-stable (19.0%; 17.1%-20.0%; n=903), and elevated-increasing (4.8%; 4.0%-5.5%; n=217). Compared with the low-stable group, trajectories with elevated BP levels had greater odds of having a CAC score of 100 HU or greater. Adjusted odds ratios were 1.44 (95% CI, 0.83-2.49) for moderate-stable, 1.86 (95% CI, 0.91-3.82) for moderate-increasing, 2.28 (95% CI, 1.24-4.18), for elevated-stable, and 3.70 (95% CI, 1.66-8.20) for elevated-increasing groups. The adjusted prevalence of a CAC score of 100 HU or higher was 5.8% in the low-stable group. These odds ratios represent an absolute increase of 2.7%, 5%, 6.3%, and 12.9% for the prevalence of a CAC score of 100 HU or higher for the moderate-stable, moderate-increasing, elevated-stable and elevated-increasing groups, respectively, compared with the low-stable group. Associations were not altered after adjustment for baseline and year 25 BP. Findings were similar for trajectories of isolated systolic BP trajectories but were attenuated for diastolic BP trajectories. CONCLUSIONS AND RELEVANCE Blood pressure trajectories throughout young adulthood vary, and higher BP trajectories were associated with an increased risk of CAC in middle age. Long-term trajectories in BP may assist in more accurate identification of individuals with subclinical atherosclerosis.
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