Associations between long-term exposure to air pollution and kidney function utilizing electronic healthcare records: a cross-sectional study.

BACKGROUND: Chronic kidney disease (CKD) affects more than 38 million people in the United States, predominantly those over 65 years of age. While CKD etiology is complex, recent research suggests associations with environmental exposures. METHODS: Our primary objective is to examine creatinine-based estimated glomerular filtration rate (eGFRcr) and diagnosis of CKD and potential associations with fine particulate matter (PM2.5), ozone (O3), and nitrogen dioxide (NO2) using a random sample of North Carolina electronic healthcare records (EHRs) from 2004 to 2016. We estimated eGFRcr using the serum creatinine-based 2021 CKD-EPI equation. PM2.5 and NO2 data come from a hybrid model using 1 km2 grids and O3 data from 12 km2 CMAQ grids. Exposure concentrations were 1-year averages. We used linear mixed models to estimate eGFRcr per IQR increase of pollutants. We used multiple logistic regression to estimate associations between pollutants and first appearance of CKD. We adjusted for patient sex, race, age, comorbidities, temporality, and 2010 census block group variables. RESULTS: We found 44,872 serum creatinine measurements among 7,722 patients. An IQR increase in PM2.5 was associated with a 1.63 mL/min/1.73m2 (95% CI: -1.96, -1.31) reduction in eGFRcr, with O3 and NO2 showing positive associations. There were 1,015 patients identified with CKD through e-phenotyping and ICD codes. None of the environmental exposures were positively associated with a first-time measure of eGFRcr < 60 mL/min/1.73m2. NO2 was inversely associated with a first-time diagnosis of CKD with aOR of 0.77 (95% CI: 0.66, 0.90). CONCLUSIONS: One-year average PM2.5 was associated with reduced eGFRcr, while O3 and NO2 were inversely associated. Neither PM2.5 or O3 were associated with a first-time identification of CKD, NO2 was inversely associated. We recommend future research examining the relationship between air pollution and impaired renal function.

Associations between source-apportioned PM2.5 and 30-day readmissions in heart failure patients.

BACKGROUND: Air pollution exposure is a significant risk factor for morbidity and mortality, especially for those with pre-existing chronic disease. Previous studies highlighted the risks that long-term particulate matter exposure has for readmissions. However, few studies have evaluated source and component specific associations particularly among vulnerable patient populations. OBJECTIVES: Use electronic health records from 5556 heart failure (HF) patients diagnosed between July 5, 2004 and December 31, 2010 that were part of the EPA CARES resource in conjunction with modeled source-specific fine particulate matter (PM2.5) to estimate the association between exposure to source and component apportioned PM2.5 at the time of HF diagnosis and 30-day readmissions. METHODS: We used zero-inflated mixed effects Poisson models with a random intercept for zip code to model associations while adjusting for age at diagnosis, year of diagnosis, race, sex, smoking status, and neighborhood socioeconomic status. We undertook several sensitivity analyses to explore the impact of geocoding precision and other factors on associations and expressed associations per interquartile range increase in exposures. RESULTS: We observed associations between 30-day readmissions and an interquartile range increase in gasoline- (16.9% increase; 95% confidence interval = 4.8%, 30.4%) and diesel-derived PM2.5 (9.9% increase; 95% confidence interval = 1.7%, 18.7%), and the secondary organic carbon component of PM2.5 (SOC; 20.4% increase; 95% confidence interval = 8.3%, 33.9%). Associations were stable in sensitivity analyses, and most consistently observed among Black study participants, those in lower income areas, and those diagnosed with HF at an earlier age. Concentration-response curves indicated a linear association for diesel and SOC. While there was some non-linearity in the gasoline concentration-response curve, only the linear component was associated with 30-day readmissions. DISCUSSION: There appear to be source specific associations between PM2.5 and 30-day readmissions particularly for traffic-related sources, potentially indicating unique toxicity of some sources for readmission risks that should be further explored.

Prescribed fires, smoke exposure, and hospital utilization among heart failure patients.

BACKGROUND: Prescribed fires often have ecological benefits, but their environmental health risks have been infrequently studied. We investigated associations between residing near a prescribed fire, wildfire smoke exposure, and heart failure (HF) patients' hospital utilization. METHODS: We used electronic health records from January 2014 to December 2016 in a North Carolina hospital-based cohort to determine HF diagnoses, primary residence, and hospital utilization. Using a cross-sectional study design, we associated the prescribed fire occurrences within 1, 2, and 5 km of the patients' primary residence with the number of hospital visits and 7- and 30-day readmissions. To compare prescribed fire associations with those observed for wildfire smoke, we also associated zip code-level smoke density data designed to capture wildfire smoke emissions with hospital utilization amongst HF patients. Quasi-Poisson regression models were used for the number of hospital visits, while zero-inflated Poisson regression models were used for readmissions. All models were adjusted for age, sex, race, and neighborhood socioeconomic status and included an offset for follow-up time. The results are the percent change and the 95% confidence interval (CI). RESULTS: Associations between prescribed fire occurrences and hospital visits were generally null, with the few associations observed being with prescribed fires within 5 and 2 km of the primary residence in the negative direction but not the more restrictive 1 km radius. However, exposure to medium or heavy smoke (primarily from wildfires) at the zip code level was associated with both 7-day (8.5% increase; 95% CI = 1.5%, 16.0%) and 30-day readmissions (5.4%; 95% CI = 2.3%, 8.5%), and to a lesser degree, hospital visits (1.5%; 95% CI: 0.0%, 3.0%) matching previous studies. CONCLUSIONS: Area-level smoke exposure driven by wildfires is positively associated with hospital utilization but not proximity to prescribed fires.

Short-term PM2.5 exposure and early-readmission risk: a retrospective cohort study in North Carolina heart failure patients.

BACKGROUND: Short-term changes in ambient fine particulate matter (PM2.5) increase the risk for unplanned hospital readmissions. However, this association has not been fully evaluated for high-risk patients or examined to determine if the readmission risk differs based on time since discharge. Here we investigate the relation between ambient PM2.5 and 30-day readmission risk in heart failure (HF) patients using daily time windows and examine how this risk varies with respect to time following discharge. METHODS: We performed a retrospective cohort study of 17,674 patients with a recorded HF diagnosis between 2004 and 2016. The cohort was identified using the EPA CARES electronic health record resource. The association between ambient daily PM2.5 (µg/m3) concentration and 30-day readmissions was evaluated using time-dependent Cox proportional hazard models. PM2.5 associated readmission risk was examined throughout the 30-day readmission period and for early readmissions (1-3 days post-discharge). Models for 30-day readmissions included a parametric continuous function to estimate the daily PM2.5 associated readmission hazard. Fine-resolution ambient PM2.5 data were assigned to patient residential address and hazard ratios are expressed per 10 µg/m3 of PM2.5. Secondary analyses examined potential effect modification based on the time after a HF diagnosis, urbanicity, medication prescription, comorbidities, and type of HF. RESULTS: The hazard of a PM2.5-related readmission within 3 days of discharge was 1.33 (95% CI 1.18-1.51). This PM2.5 readmission hazard was slightly elevated in patients residing in non-urban areas (1.43, 95%CI 1.22-1.67) and for HF patients without a beta-blocker prescription prior to the readmission (1.35; 95% CI 1.19-1.53). CONCLUSION: Our findings add to the evidence indicating substantial air quality-related health risks in individuals with underlying cardiovascular disease. Hospital readmissions are key metrics for patients and providers alike. As a potentially modifiable risk factor, air pollution-related interventions may be enacted that might assist in reducing costly and burdensome unplanned readmissions.

Dental morphology and microstructure of the Prickly Dogfish Oxynotus bruniensis (Squaliformes: Oxynotidae).

This study describes and illustrates the jaws, teeth, and tooth microstructure of the Prickly Dogfish Oxynotus bruniensis. Detailed accounts of the dental morphology of O. bruniensis are rare and have not addressed the tissue arrangement or microstructure of the teeth. These features are documented and discussed in the contexts of interspecific comparisons with other elasmobranchs and the dietary specialization of O. bruniensis. The overall tooth morphology of O. bruniensis is similar to those of other closely related members in the order Squaliformes, as is the tissue arrangement, or histotype. Oxynotus bruniensis exhibits a simplified enameloid microstructure, which we compare with previously documented enameloid microstructures of other elasmobranchs. Though subtle interspecific differences in dental characters are documented, neither overall tooth morphology nor histotype and microstructure are unique to O. bruniensis. We conclude that in the case of O. bruniensis, dietary specialization is facilitated by behavioral rather than morphological specialization.

Bite performance and feeding behaviour of the sand tiger shark Carcharias taurus.

This study examines the feeding behaviour and kinematics of three sub-adult sand tiger sharks Carcharias taurus on display at Mystic Aquarium (Mystic, Connecticut, USA). Using high-speed video data from 52 bites, we identify kinematic variables associated with the expansive and compressive phases of the bite. The mean bite duration from the onset of the expansive phase to the conclusion of the compressive phase is mean (± SE) 0.14 ± 0.01 s and across the 10 fastest bites of each individual, the maximum performance average is 0.13 ± 0.01 s. Values of maximum performance do not vary significantly among individuals. When compared with kinematic bite data from species studied previously, these results indicate that body size is not the only determinant factor of bite duration. This study also provides detailed descriptions of feeding behaviours in C. taurus and presents documentation of tooth loss both prior to and during feeding, suggesting that there are multiple mechanisms of tooth loss and use in C. taurus. Finally, we discuss the behavioural and ecological components of prey capture in C. taurus and suggest points of consideration to facilitate interspecific comparisons of prey capture performance in ram-feeding, macrophagous elasmobranchs.

A new species of deep-sea Booralana Bruce, 1986 (Crustacea: Isopoda: Cirolanidae) from The Bahamas, Western North Atlantic.

Booralana nickorum sp. nov. is described from the deep-water slope of the Exuma Sound, The Bahamas, from depths of 540 to 560 metres. It is the fourth species to be assigned to the genus and the second species described from the Western North Atlantic. The species can be distinguished from Booralana tricarinata Camp and Heard, 1988 and the other species by the sub-triangular pleotelson and the uropodal exopod of mature males being far longer than endopod, with both rami extending well beyond the posterior margin of the pleotelson. Additionally, pleopods 3 and 4 lack a prominent angle at midpoint of ramus.

Associations between long-term fine particulate matter exposure and hospital procedures in heart failure patients.

BACKGROUND: Ambient fine particulate matter (PM2.5) contributes to global morbidity and mortality. One way to understand the health effects of PM2.5 is by examining its impact on performed hospital procedures, particularly among those with existing chronic disease. However, such studies are rare. Here, we investigated the associations between annual average PM2.5 and hospital procedures among individuals with heart failure. METHODS: Using electronic health records from the University of North Carolina Healthcare System, we created a retrospective cohort of 15,979 heart failure patients who had at least one of 53 common (frequency > 10%) procedures. We used daily modeled PM2.5 at 1x1 km resolution to estimate the annual average PM2.5 at the time of heart failure diagnosis. We used quasi-Poisson models to estimate associations between PM2.5 and the number of performed hospital procedures over the follow-up period (12/31/2016 or date of death) while adjusting for age at heart failure diagnosis, race, sex, year of visit, and socioeconomic status. RESULTS: A 1 µg/m3 increase in annual average PM2.5 was associated with increased glycosylated hemoglobin tests (10.8%; 95% confidence interval = 6.56%, 15.1%), prothrombin time tests (15.8%; 95% confidence interval = 9.07%, 22.9%), and stress tests (6.84%; 95% confidence interval = 3.65%, 10.1%). Results were stable under multiple sensitivity analyses. CONCLUSIONS: These results suggest that long-term PM2.5 exposure is associated with an increased need for diagnostic testing on heart failure patients. Overall, these associations give a unique lens into patient morbidity and potential drivers of healthcare costs linked to PM2.5 exposure.

Associations between PFAS occurrence and multimorbidity as observed in an electronic health record cohort.

Per and polyfluoroalkyl substances (PFAS) are associated with health outcomes ranging from cancer to high cholesterol. However, there has been little examination of how PFAS exposure might impact the development of multiple chronic diseases, known as multimorbidity. Here, we associated the presence of one or more PFAS in water systems serving the zip code of residence with chronic disease and multimorbidity. Methods: We used data from the unregulated contaminant monitoring rule 3 to estimate exposure to PFAS for a random sample of 10,168 patients from the University of North Carolina Healthcare System. The presence of 16 chronic diseases was determined via. their electronic health records. We used a logistic regression model in a cross-sectional study design to associate the presence of one or more PFAS with multimorbidity. Models were adjusted for age, race, sex, smoking status, socioeconomic status, and 20 county-level confounders. Results: There were four PFAS found in water systems that served at least one zip code represented in our patient data: PFOA, PFHpA, PFOS, and PFHxS. Exposure to any PFAS was associated with a odds ratio of 1.25 for multimorbidity (95% confidence interval = 1.09, 1.45). Among the chronic diseases with at least 300 cases, we observed associations with dyslipidemia, hypertension, ischemic heart disease, and osteoporosis. Conclusion: Exposure to PFAS is associated with a range of chronic diseases as well as multimorbidity. Accounting for the joint impacts of PFAS on multiple chronic conditions may give an increasingly clear picture of the public health impacts of PFAS.

Associations between short-term exposure to PM2.5 and cardiomyocyte injury in myocardial infarction survivors in North Carolina.

OBJECTIVE: Short-term ambient fine particulate matter (PM2.5) is associated with adverse cardiovascular events including myocardial infarction (MI). However, few studies have examined associations between PM2.5 and subclinical cardiomyocyte damage outside of overt cardiovascular events. Here we evaluate the impact of daily PM2.5 on cardiac troponin I, a cardiomyocyte specific biomarker of cellular damage. METHODS: We conducted a retrospective cohort study of 2924 patients identified using electronic health records from the University of North Carolina Healthcare System who had a recorded MI between 2004 and 2016. Troponin I measurements were available from 2014 to 2016, and were required to be at least 1 week away from a clinically diagnosed MI. Daily ambient PM2.5 concentrations were estimated at 1 km resolution and assigned to patient residence. Associations between log-transformed troponin I and daily PM2.5 were evaluated using distributed lag linear mixed effects models adjusted for patient demographics, socioeconomic status and meteorology. RESULTS: A 10 µg/m3 elevation in PM2.5 3 days before troponin I measurement was associated with 0.06 ng/mL higher troponin I (95% CI=0.004 to 0.12). In stratified models, this association was strongest in patients that were men, white and living in less urban areas. Similar associations were observed when using 2-day rolling averages and were consistently strongest when using the average exposure over the 5 days prior to troponin I measurement. CONCLUSIONS: Daily elevations in PM2.5 were associated with damage to cardiomyocytes, outside of the occurrence of an MI. Poor air quality may cause persistent damage to the cardiovascular system leading to increased risk of cardiovascular disease and adverse cardiovascular events.

Extreme Morphology, Functional Trade-offs, and Evolutionary Dynamics in a Clade of Open-Ocean Fishes (Perciformes: Bramidae).

When novel or extreme morphologies arise, they are oft met with the burden of functional trade-offs in other aspects of anatomy, which may limit phenotypic diversification and make particular adaptive peaks inaccessible. Bramids (Perciformes: Bramidae) comprise a small family of 20 extant species of fishes, which are distributed throughout pelagic waters worldwide. Within the Bramidae, the fanfishes (Pteraclis and Pterycombus) differ morphologically from the generally stout, laterally compressed species that typify the family. Instead, Pteraclis and Pterycombus exhibit extreme anterior positioning of the dorsal fin onto the craniofacial skeleton. Consequently, they possess fin and skull anatomies that are radically different from other bramid species. Here, we investigate the anatomy, development, and evolution of the Bramidae to test the hypothesis that morphological innovations come at functional (proximate) and evolutionary (ultimate) costs. Addressing proximate effects, we find that the development of an exaggerated dorsal fin is associated with neurocrania modified to accommodate an anterior expansion of the dorsal fin. This occurs via reduced development of the supraoccipital crest (SOC), providing a broad surface area on the skull for insertion of the dorsal fin musculature. While these anatomical shifts are presumably associated with enhanced maneuverability in fanfishes, they are also predicted to result in compromised suction feeding, possibly limiting the mechanisms of feeding in this group. Phylogenetic analyses suggest craniofacial and fin morphologies of fanfishes evolved rapidly and are evolutionarily correlated across bramids. Furthermore, fanfishes exhibit a similar rate of lineage diversification as the rest of the Bramidae, lending little support for the prediction that exaggerated medial fins are associated with phylogenetic constraint. Our phylogeny places fanfishes at the base of the Bramidae and suggests that nonfanfish bramids have reduced medial fins and re-evolved SOCs. These observations suggest that the evolution of novel fin morphologies in basal species has led to the phylogenetic coupling of head and fin shape, possibly predisposing the entire family to a limited range of feeding. Thus, the evolution of extreme morphologies may have carryover effects, even after the morphology is lost, limiting ecological diversification of lineages.

新規または極端な形態が発生すると、解剖学的構造の他の側面で機能的なトレードオフの負担に直面することが多く、表現型の多様化が制限され、特定の適応ピークにアクセスできなくなる可能性があります。ブラミド（スズキ目：シマガツオ科）は、20種の現存する魚の小さな家族で構成されており、世界中の遠洋水域に分布しています。ブラミダエ内では、シマガツオ（PteraclisとPterycombus）は、家族を代表する一般的に頑丈な横方向に圧縮された種と形態学的に異なります。代わりに、PteraclisとPterycombusは、頭蓋顔面骨格への背びれの極端な前方位置を示します。その結果、それらは他のブラミド種とは根本的に異なるひれと頭蓋骨の解剖学的構造を持っています。ここでは、形態学的革新が機能的（近接）および進化的（究極）コストでもたらされるという仮説をテストするために、ブラミダエの解剖学、発達、および進化を調査します。近接効果に対処すると、誇張された背びれの発達は、背びれの前方拡張に対応するように修正された脳頭蓋に関連していることがわかります。これは、後頭上頂（SOC）の発達の低下を介して発生し、背びれの筋肉組織を挿入するための頭蓋骨の広い表面積を提供します。これらの解剖学的変化はおそらくファンフィッシュの操作性の向上に関連していると思われますが、吸引餌の低下をもたらし、このグループの餌のメカニズムを制限する可能性もあると予測されています。系統発生分析は、シマガツオの頭蓋顔面およびヒレの形態が急速に進化し、ブラミド間で進化的に相関していることを示唆しています。さらに、ファンフィッシュは他のブラミダエと同様の系統多様化率を示し、誇張された内側のひれが系統発生の制約に関連しているという予測をほとんど支持していません。私たちの系統発生は、シマガツオをシマガツオ科の根元に配置し、シマガツオ以外のシマガツオが内側のひれを減らし、SOCを再進化させたことを示唆しています。これらの観察結果は、基底種における新しいヒレの形態の進化が、頭とヒレの形状の系統発生的結合をもたらし、おそらく家族全員が限られた範囲の摂食にかかりやすくなっていることを示唆しています。したがって、極端な形態の進化は、形態が失われた後でも持ち越し効果をもたらす可能性があり、系統の生態学的多様化を制限します。.

Cuando surgen morfologías nuevas o extremas, a menudo se encuentran con la carga de compensaciones funcionales en otros aspectos de la anatomía, lo que puede limitar la diversificación fenotípica y hacer inaccesibles los picos adaptativos particulares. Las bramidas (Perciformes: Bramidae) comprenden una pequeña familia de 20 especies de peces existentes, que se distribuyen en las aguas pelágicas de todo el mundo. Dentro de los Bramidae, los fanfishes (Pteraclis y Pterycombus) difieren morfológicamente de las especies generalmente robustas y comprimidas lateralmente que caracterizan a la familia. En cambio, Pteraclis y Pterycombus exhiben una posición anterior extrema de la aleta dorsal sobre el esqueleto craneofacial. En consecuencia, poseen anatomías de aletas y cráneo que son radicalmente diferentes de otras especies de bramidas. Aquí, investigamos la anatomía, el desarrollo y la evolución de Bramidae para probar la hipótesis de que las innovaciones morfológicas tienen un costo funcional (próximo) y evolutivo (último). Al abordar los efectos inmediatos, encontramos que el desarrollo de una aleta dorsal exagerada se asocia con neurocráneo modificado para adaptarse a una expansión anterior de la aleta dorsal. Esto ocurre a través del desarrollo reducido de la cresta supraoccipital (SOC), proporcionando una amplia área de superficie en el cráneo para la inserción de la musculatura de la aleta dorsal. Si bien estos cambios anatómicos presumiblemente están asociados con una mayor maniobrabilidad en los peces fanfishes, también se predice que darán como resultado una alimentación por succión comprometida, lo que posiblemente limite los mecanismos de alimentación en este grupo. Los análisis filogenéticos sugieren que las morfologías craneofaciales y de aletas de los fanfishes evolucionaron rápidamente y están correlacionadas evolutivamente entre las bramidas. Además, los fanfishes exhiben una tasa similar de diversificación de linajes que el resto de los Bramidae, lo que brinda poco apoyo a la predicción de que las aletas mediales exageradas están asociadas con restricciones filogenéticas. Nuestra filogenia coloca a los peces abanico en la base de las Bramidae y sugiere que las bramidas que no son peces abanico tienen aletas mediales reducidas y SOC reevolucionado. Estas observaciones sugieren que la evolución de nuevas morfologías de aletas en especies basales ha llevado al acoplamiento filogenético de la forma de la cabeza y la aleta, lo que posiblemente predisponga a toda la familia a un rango limitado de alimentación. Por lo tanto, la evolución de morfologías extremas puede tener efectos de arrastre, incluso después de que se pierde la morfología, lo que limita la diversificación ecológica de los linajes.

Quando surgem morfologias novas ou extremas, muitas vezes enfrentam o fardo de compensações funcionais em outros aspectos da anatomia, que podem limitar a diversificação fenotípica e tornar determinados picos adaptativos inacessíveis. Bramids (Perciformes: Bramidae) compreendem uma pequena família de 20 espécies existentes de peixes, que estão distribuídos em águas pelágicas em todo o mundo. Dentro dos Bramidae, os fanfishes (Pteraclis e Pterycombus) diferem morfologicamente das espécies geralmente robustas e comprimidas lateralmente que tipificam a família. Em vez disso, Pteraclis e Pterycombus exibem posicionamento anterior extremo da nadadeira dorsal no esqueleto craniofacial. Conseqüentemente, eles possuem anatomias de barbatana e crânio que são radicalmente diferentes de outras espécies de bramida. Aqui, investigamos a anatomia, o desenvolvimento e a evolução dos Bramidae para testar a hipótese de que as inovações morfológicas têm custos funcionais (proximais) e evolutivos (finais). Abordando os efeitos imediatos, descobrimos que o desenvolvimento de uma nadadeira dorsal exagerada está associado a neurocrania modificada para acomodar uma expansão anterior da nadadeira dorsal. Isso ocorre por meio do desenvolvimento reduzido da crista supraoccipital (SOC), proporcionando uma ampla área de superfície no crânio para a inserção da musculatura da nadadeira dorsal. Embora essas mudanças anatômicas estejam presumivelmente associadas a maior capacidade de manobra em peixes-leque, também se prevê que resultem em alimentação de sucção comprometida, possivelmente limitando os mecanismos de alimentação neste grupo. As análises filogenéticas sugerem que as morfologias craniofaciais e das nadadeiras de fanfishes evoluíram rapidamente e estão evolutivamente correlacionadas entre as bramidas. Além disso, fanfishes exibem uma taxa semelhante de diversificação de linhagem como o resto dos Bramidae, emprestando pouco suporte para a previsão de que nadadeiras mediais exageradas estão associadas a restrições filogenéticas. Nossa filogenia coloca fanfishes na base dos Bramidae e sugere que bramids não fanfish possuem nadadeiras mediais reduzidas e SOCs re-evoluídos. Essas observações sugerem que a evolução de novas morfologias de nadadeiras em espécies basais levou ao acoplamento filogenético da forma da cabeça e da nadadeira, possivelmente predispondo toda a família a uma faixa limitada de alimentação. Assim, a evolução de morfologias extremas pode ter efeitos de transporte, mesmo após a perda da morfologia, limitando a diversificação ecológica das linhagens.

Long-Term Exposure to Particulate Air Pollution Is Associated With 30-Day Readmissions and Hospital Visits Among Patients With Heart Failure.

Background Long-term air pollution exposure is a significant risk factor for inpatient hospital admissions in the general population. However, we lack information on whether long-term air pollution exposure is a risk factor for hospital readmissions, particularly in individuals with elevated readmission rates. Methods and Results We determined the number of readmissions and total hospital visits (outpatient visits+emergency room visits+inpatient admissions) for 20 920 individuals with heart failure. We used quasi-Poisson regression models to associate annual average fine particulate matter at the date of heart failure diagnosis with the number of hospital visits and 30-day readmissions. We used inverse probability weights to balance the distribution of confounders and adjust for the competing risk of death. Models were adjusted for age, race, sex, smoking status, urbanicity, year of diagnosis, short-term fine particulate matter exposure, comorbid disease, and socioeconomic status. A 1-µg/m3 increase in fine particulate matter was associated with a 9.31% increase (95% CI, 7.85%-10.8%) in total hospital visits, a 4.35% increase (95% CI, 1.12%-7.68%) in inpatient admissions, and a 14.2% increase (95% CI, 8.41%-20.2%) in 30-day readmissions. Associations were robust to different modeling approaches. Conclusions These results highlight the potential for air pollution to play a role in hospital use, particularly hospital visits and readmissions. Given the elevated frequency of hospitalizations and readmissions among patients with heart failure, these results also represent an important insight into modifiable environmental risk factors that may improve outcomes and reduce hospital use among patients with heart failure.

Shark teeth as edged weapons: serrated teeth of three species of selachians.

Prior to European contact, South Pacific islanders used serrated shark teeth as components of tools and weapons. They did this because serrated shark teeth are remarkably effective at slicing through soft tissues. To understand more about the forms and functions of serrated shark teeth, we examined the morphology and histology of tooth serrations in three species: the Tiger Shark (Galeocerdo cuvier), Blue Shark (Prionace glauca), and White Shark (Carcharodon carcharias). We show that there are two basic types of serrations. A primary serration consists of three layers of enameloid with underlying dentine filling the serration's base. All three species studied have primary serrations, although the dentine component differs (orthodentine in Tiger and Blue Sharks; osteodentine in the White Shark). Smaller secondary serrations are found in the Tiger Shark, formed solely by enameloid with no contribution from underlying dentine. Secondary serrations are effectively "serrations within serrations" that allow teeth to cut at different scales. We propose that the cutting edges of Tiger Shark teeth, equipped with serrations at different scales, are linked to a diet that includes large, hard-shelled prey (e.g., sea turtles) as well as smaller, softer prey such as fishes. We discuss other aspects of serration form and function by making analogies to man-made cutting implements, such as knives and saws.

Development and microstructure of tooth histotypes in the blue shark, Prionace glauca (Carcharhiniformes: Carcharhinidae) and the great white shark, Carcharodon carcharias (Lamniformes: Lamnidae).

Elasmobranchs exhibit two distinct arrangements of mineralized tissues in the teeth that are known as orthodont and osteodont histotypes. Traditionally, it has been said that orthodont teeth maintain a pulp cavity throughout tooth development whereas osteodont teeth are filled with osteodentine and lack a pulp cavity when fully developed. We used light microscopy, scanning electron microscopy, and high-resolution micro-computed tomography to compare the structure and development of elasmobranch teeth representing the two histotypes. As an example of the orthodont histotype, we studied teeth of the blue shark, Prionace glauca (Carcharhiniformes: Carcharhinidae). For the osteodont histotype, we studied teeth of the great white shark, Carcharodon carcharias (Lamniformes: Lamnidae). We document similarities and differences in tooth development and the microstructure of tissues in these two species and review the history of definitions and interpretations of elasmobranch tooth histotypes. We discuss a possible correlation between tooth histotype and tooth replacement and review the history of histotype differentiation in sharks. We find that contrary to a long held misconception, there is no orthodentine in the osteodont teeth of C. carcharias.