Estimating a social cost of carbon for global energy consumption.

Estimates of global economic damage caused by carbon dioxide (CO2) emissions can inform climate policy1-3. The social cost of carbon (SCC) quantifies these damages by characterizing how additional CO2 emissions today impact future economic outcomes through altering the climate4-6. Previous estimates have suggested that large, warming-driven increases in energy expenditures could dominate the SCC7,8, but they rely on models9-11 that are spatially coarse and not tightly linked to data2,3,6,7,12,13. Here we show that the release of one ton of CO2 today is projected to reduce total future energy expenditures, with most estimates valued between -US$3 and -US$1, depending on discount rates. Our results are based on an architecture that integrates global data, econometrics and climate science to estimate local damages worldwide. Notably, we project that emerging economies in the tropics will dramatically increase electricity consumption owing to warming, which requires critical infrastructure planning. However, heating reductions in colder countries offset this increase globally. We estimate that 2099 annual global electricity consumption increases by about 4.5 exajoules (7 per cent of current global consumption) per one-degree-Celsius increase in global mean surface temperature (GMST), whereas direct consumption of other fuels declines by about 11.3 exajoules (7 per cent of current global consumption) per one-degree-Celsius increase in GMST. Our finding of net savings contradicts previous research7,8, because global data indicate that many populations will remain too poor for most of the twenty-first century to substantially increase energy consumption in response to warming. Importantly, damage estimates would differ if poorer populations were given greater weight14.

New evidence on the impact of sustained exposure to air pollution on life expectancy from China's Huai River Policy.

This paper finds that a 10-µg/m3 increase in airborne particulate matter [particulate matter smaller than 10 µm (PM10)] reduces life expectancy by 0.64 years (95% confidence interval = 0.21-1.07). This estimate is derived from quasiexperimental variation in PM10 generated by China's Huai River Policy, which provides free or heavily subsidized coal for indoor heating during the winter to cities north of the Huai River but not to those to the south. The findings are derived from a regression discontinuity design based on distance from the Huai River, and they are robust to using parametric and nonparametric estimation methods, different kernel types and bandwidth sizes, and adjustment for a rich set of demographic and behavioral covariates. Furthermore, the shorter lifespans are almost entirely caused by elevated rates of cardiorespiratory mortality, suggesting that PM10 is the causal factor. The estimates imply that bringing all of China into compliance with its Class I standards for PM10 would save 3.7 billion life-years.

Evidence on the impact of sustained exposure to air pollution on life expectancy from China's Huai River policy.

This paper's findings suggest that an arbitrary Chinese policy that greatly increases total suspended particulates (TSPs) air pollution is causing the 500 million residents of Northern China to lose more than 2.5 billion life years of life expectancy. The quasi-experimental empirical approach is based on China's Huai River policy, which provided free winter heating via the provision of coal for boilers in cities north of the Huai River but denied heat to the south. Using a regression discontinuity design based on distance from the Huai River, we find that ambient concentrations of TSPs are about 184 µg/m(3) [95% confidence interval (CI): 61, 307] or 55% higher in the north. Further, the results indicate that life expectancies are about 5.5 y (95% CI: 0.8, 10.2) lower in the north owing to an increased incidence of cardiorespiratory mortality. More generally, the analysis suggests that long-term exposure to an additional 100 µg/m(3) of TSPs is associated with a reduction in life expectancy at birth of about 3.0 y (95% CI: 0.4, 5.6).

Prolonged antibiotics for non-cystic fibrosis bronchiectasis in children and adults.

BACKGROUND: The vicious cycle hypothesis for bronchiectasis predicts that bacterial colonisation of the respiratory tract perpetuates inflammatory change. This damages the mucociliary escalator, preventing bacterial clearance and allowing persistence of pro-inflammatory mediators. Conventional treatment with physiotherapy and intermittent antibiotics is believed to improve the condition of people with bronchiectasis, although no conclusive data show that these interventions influence the natural history of the condition. Various strategies have been tried to interrupt this cycle of infection and inflammation, including prolonging antibiotic treatment with the goal of allowing the airway mucosa to heal. OBJECTIVES: To determine the benefits of prolonged antibiotic therapy in the treatment of patients with bronchiectasis. SEARCH METHODS: We searched the Cochrane Airways Group Trials Register and reference lists of identified articles. Searches were current as of February 2014. SELECTION CRITERIA: Randomised trials examining the use of prolonged antibiotic therapy (for four or more weeks) in the treatment of bronchiectasis compared with placebo or usual care. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trial quality and extracted data. We contacted study authors to ask for missing information. MAIN RESULTS: Eighteen trials met the inclusion criteria, randomly assigning a total of 1157 participants. Antibiotics were given for between four weeks and 83 weeks. Limited meta-analysis was possible because of the diversity of outcomes reported in these trials. Based on the number of participants with at least one exacerbation, the meta-analysis showed significant effects in favour of the intervention (odds ratio (OR) 0.31, 95% confidence interval (CI) 0.19 to 0.52; P value < 0.00001), with events occurring in 271 per 1000 people in the intervention arm (95% CI 126 to 385) and in 546 per 1000 in the control population, based on evidence of moderate quality. A non-statistically significant reduction in hospitalisation favoured the use of prolonged antibiotics with a moderate quality grade of supporting evidence (37 per 1000 in the intervention arm (95% CI 13 to 96) and 87 per 1000 in control (OR 0.40, 95% CI 0.14 to 1.11; P value = 0.08). Drug resistance developed in 36 of 220 participants taking antibiotics compared with 10 of 211 participants given placebo or standard therapy (OR 3.48, 95% CI 1.20 to 10.07; P value = 0.02), translating to natural frequencies of 155 per 1000 in the intervention arm (95% CI 59 to 346) and 50 per 1000 in the control arm. The intervention was well tolerated with no overall significant difference in withdrawal between treatment and placebo groups (OR 0.91, 95% CI 0.56 to 1.49). Diarrhoea was commonly reported as an adverse event, particularly with an oral intervention. AUTHORS' CONCLUSIONS: Available evidence shows benefit associated with use of prolonged antibiotics in the treatment of patients with bronchiectasis, at least halving the odds of exacerbation (with 275 fewer exacerbations per every 1000 people treated in the antibiotic arm compared with the control arm) and hospitalisation (50 fewer hospitalisations per 1000 people in the antibiotic arm compared with the control arm). However, the risk of emerging drug resistance is increased more than threefold. This review is limited by diversity of trials and by evidence of moderate to low quality. Further randomised controlled trials with adequate power and standardised end points are required.

Environmental Health Risks and Housing Values: Evidence from 1,600 Toxic Plant Openings and Closings.

Regulatory oversight of toxic emissions from industrial plants and understanding about these emissions' impacts are in their infancy. Applying a research design based on the openings and closings of 1,600 industrial plants to rich data on housing markets and infant health, we find that: toxic air emissions affect air quality only within 1 mile of the plant; plant openings lead to 11 percent declines in housing values within 0.5 mile or a loss of about $4.25 million for these households; and a plant's operation is associated with a roughly 3 percent increase in the probability of low birthweight within 1 mile.

Endoscopic duodenal-jejunal bypass liner treatment of moderate obstructive sleep apnoea-A pilot study.

We aimed to assess the extent to which people with type 2 diabetes or pre-diabetes, obesity (BMI 30-45 kg/m2) and moderate obstructive sleep apnoea (OSA) requiring continuous positive airway pressure ventilation (CPAP) were able to discontinue CPAP following EndoBarrier-related weight loss. We assessed sleep and metabolic parameters before, during and after EndoBarrier in 12 participants with moderate OSA requiring CPAP (75% female, 8/12 [66%] type 2 diabetes, 4/12 [34%] prediabetes, mean ± SD age 52.6 ± 9.7 years, BMI 37.4 ± 3.5 kg/m2, median duration of OSA while on CPAP 9.0 [7.0-15.0] months). With EndoBarrier in-situ, mean ± SD Apnoea Hypopnoea Index (AHI) fell by 9.1 ± 5.0 events/h from 18.9 ± 3.8 to 9.7 ± 3.0 events/h (p < .001) with an associated reduction in symptoms of daytime sleepiness (mean Epworth Sleepiness Score) such that all the 12 participants no longer required CPAP according to National Institute for Health and Care Excellence criteria. After EndoBarrier removal, 10/12 (83%) patients attended follow-up and at 12 months after removal, AHI remained below 15 in 5/10 (50%) patients but in other five the AHI rose above 15 such that restarting CPAP was recommended as justified by their symptoms. Rather than restart CPAP, two patients lost the regained weight and their AHI dropped below 15 again. Thus, 7/10 (70%) of patients were able to remain off CPAP 12 or more months after EndoBarrier removal. These results demonstrate major benefit of EndoBarrier in moderate OSA, allowing all patients to discontinue CPAP during treatment, and with maintenance of improvement at follow-up in 70%. They confirm previously demonstrated metabolic improvements in diabetes and obesity.

Mandatory disclosure would reveal corporate carbon damages.

Accurate reporting is critical for markets and climate policies.

Hospital at home for acute exacerbations of chronic obstructive pulmonary disease.

BACKGROUND: Hospital at home schemes are a recently adopted method of service delivery for the management of acute exacerbations of chronic obstructive pulmonary disease (COPD) aimed at reducing demand for acute hospital inpatient beds and promoting a patient-centred approach through admission avoidance. However, evidence in support of such a service is contradictory. OBJECTIVES: To evaluate the efficacy of hospital at home compared to hospital inpatient care in acute exacerbations of COPD. SEARCH METHODS: Trials were identified from searches of electronic databases, including CENTRAL, MEDLINE, EMBASE, and the Cochrane Airways Group Register (CAGR). The review authors checked the reference lists of included trials. The CAGR was searched up to February 2012. The additional databases were searched up to October 2010. SELECTION CRITERIA: We considered randomised controlled trials where patients presented to the emergency department with an exacerbation of their COPD. Studies must not have recruited patients for whom treatment at home is usually not viewed as an responsible option (e.g. patients with an impaired level of consciousness, acute confusion, acute changes on the radiograph or electrocardiogram, arterial pH less than 7.35, concomitant medical conditions). DATA COLLECTION AND ANALYSIS: Two review authors independently selected articles for inclusion, assessed the risk of bias and extracted data for each of the included trials. MAIN RESULTS: Eight trials with 870 patients were included in the review and showed a significant reduction in readmission rates for hospital at home compared with hospital inpatient care of acute exacerbations of COPD (risk ratio (RR)0.76; 95% confidence interval (CI) from 0.59 to 0.99; P=0.04). Moreover, we observed a trend towards lower mortality in the hospital at home group, but the pooled effect estimate did not reach statistical significance (RR 0.65, 95% CI 0.40 to 1.04, P = 0.07). For health-related quality of life, lung function (FEV1) and direct costs, the quality of the available evidence is in general too weak to make firm conclusions. AUTHORS' CONCLUSIONS: Selected patients presenting to hospital emergency departments with acute exacerbations of COPD can be safely and successfully treated at home with support from respiratory nurses. We found evidence of moderate quality that hospital at home may be advantageous with respect to readmission rates in these patients. Treatment of acute exacerbation of COPD in hospital at home also show a trend towards reduced mortality rate when compared with conventional inpatient treatment, but these results did not reach statistical significance (moderate quality evidence). For other outcomes than readmission and mortality rate, we assessed the evidence to be of low or very low quality.

SUPERFUND CLEANUPS AND INFANT HEALTH.

We are the first to examine the effect of Superfund cleanups on infant health rather than focusing on proximity to a site. We study singleton births to mothers residing within 5km of a Superfund site between 1989-2003 in five large states. Our "difference in differences" approach compares birth outcomes before and after a site clean-up for mothers who live within 2,000 meters of the site and those who live between 2,000- 5,000 meters of a site. We find that proximity to a Superfund site before cleanup is associated with a 20 to 25% increase in the risk of congenital anomalies.

Management of acute exacerbations of chronic obstructive pulmonary disease: the first 24 hours.

Successful outcome is more likely with early treatment and lesser degrees of acidosis. While aiming for maximum treatment for the first 24 hours, some patients improve so rapidly that they can discontinue after a shorter time. Most patients need a full face mask and oxygen, and nebulised bronchodilators can be incorporated. If radiological consolidation, excessive secretions and/or confusion are present, the chance of failure is increased but is not an absolute contraindication. The presence of a pneumothorax necessitates intercostal drainage. A useful summary statement has recently been published. Patients who are obtunded and peri-arrest require immediate intubation and mechanical ventilation. There is some evidence that intensivists are reluctant to accept COPD exacerbators to the intensive care unit because of the perceived low survival rates or concerns about weaning delays after intubation. In fact, the prognosis may be better than in many other patients with multi-organ failure. Patients can often be quickly weaned on to NIV and returned to the ward after an initial period of invasive support and secretion management. Initial assessment and the past history should identify those markedly disabled patients with recurrent admissions who are likely to be entering the terminal stages of their illness in whom intubation is inappropriate. Here, NIV may be the ceiling of treatment, providing useful symptom palliation while waiting for treatment to

Hydraulic fracturing and infant health: New evidence from Pennsylvania.

The development of hydraulic fracturing ("fracking") is considered the biggest change to the global energy production system in the last half-century. However, several communities have banned fracking because of unresolved concerns about the impact of this process on human health. To evaluate the potential health impacts of fracking, we analyzed records of more than 1.1 million births in Pennsylvania from 2004 to 2013, comparing infants born to mothers living at different distances from active fracking sites and those born both before and after fracking was initiated at each site. We adjusted for fixed maternal determinants of infant health by comparing siblings who were and were not exposed to fracking sites in utero. We found evidence for negative health effects of in utero exposure to fracking sites within 3 km of a mother's residence, with the largest health impacts seen for in utero exposure within 1 km of fracking sites. Negative health impacts include a greater incidence of low-birth weight babies as well as significant declines in average birth weight and in several other measures of infant health. There is little evidence for health effects at distances beyond 3 km, suggesting that health impacts of fracking are highly local. Informal estimates suggest that about 29,000 of the nearly 4 million annual U.S. births occur within 1 km of an active fracking site and that these births therefore may be at higher risk of poor birth outcomes.

Bilateral chylothorax: an unusual complication of cervical rib resection.

Bilateral chylothorax is a rare cause of pleural effusions. Here we report an unusual acute presentation of bilateral chylothorax following thoracic outlet surgery. Unique to this case was the disparate characteristics of pleural fluid analyses with an exudate on the left and a transudate on the right. This report describes the recognition and management of bilateral chylothoraces, an uncommon but potentially serious complication of this frequently performed surgical procedure.

Does home oxygen therapy (HOT) in addition to standard care reduce disease severity and improve symptoms in people with chronic heart failure? A randomised trial of home oxygen therapy for patients with chronic heart failure.

BACKGROUND: Home oxygen therapy (HOT) is commonly used for patients with severe chronic heart failure (CHF) who have intractable breathlessness. There is no trial evidence to support its use. OBJECTIVES: To detect whether or not there was a quality-of-life benefit from HOT given as long-term oxygen therapy (LTOT) for at least 15 hours per day in the home, including overnight hours, compared with best medical therapy (BMT) in patients with severely symptomatic CHF. DESIGN: A pragmatic, two-arm, randomised controlled trial recruiting patients with severe CHF. It included a linked qualitative substudy to assess the views of patients using home oxygen, and a free-standing substudy to assess the haemodynamic effects of acute oxygen administration. SETTING: Heart failure outpatient clinics in hospital or the community, in a range of urban and rural settings. PARTICIPANTS: Patients had to have heart failure from any aetiology, New York Heart Association (NYHA) class III/IV symptoms, at least moderate left ventricular systolic dysfunction, and be receiving maximally tolerated medical management. Patients were excluded if they had had a cardiac resynchronisation therapy device implanted within the past 3 months, chronic obstructive pulmonary disease fulfilling the criteria for LTOT or malignant disease that would impair survival or were using a device or medication that would impede their ability to use LTOT. INTERVENTIONS: Patients received BMT and were randomised (unblinded) to open-label LTOT, prescribed for 15 hours per day including overnight hours, or no oxygen therapy. MAIN OUTCOME MEASURES: The primary end point was quality of life as measured by the Minnesota Living with Heart Failure (MLwHF) questionnaire score at 6 months. Secondary outcomes included assessing the effect of LTOT on patient symptoms and disease severity, and assessing its acceptability to patients and carers. RESULTS: Between April 2012 and February 2014, 114 patients were randomised to receive either LTOT or BMT. The mean age was 72.3 years [standard deviation (SD) 11.3 years] and 70% were male. Ischaemic heart disease was the cause of heart failure in 84%; 95% were in NYHA class III; the mean left ventricular ejection fraction was 27.8%; and the median N-terminal pro-B-type natriuretic hormone was 2203 ng/l. The primary analysis used a covariance pattern mixed model which included patients only if they provided data for all baseline covariates adjusted for in the model and outcome data for at least one post-randomisation time point (n = 102: intervention, n = 51; control, n = 51). There was no difference in the MLwHF questionnaire score at 6 months between the two arms [at baseline the mean score was 54.0 (SD 18.4) for LTOT and 54.0 (SD 17.9) for BMT; at 6 months the mean score was 48.1 (SD 18.5) for LTOT and 49.0 (SD 20.2) for BMT; adjusted mean difference -0.10, 95% confidence interval (CI) -6.88 to 6.69; p = 0.98]. At 3 months, the adjusted mean MLwHF questionnaire score was lower in the LTOT group (-5.47, 95% CI -10.54 to -0.41; p = 0.03) and breathlessness scores improved, although the effect did not persist to 6 months. There was no effect of LTOT on any secondary measure. There was a greater number of deaths in the BMT arm (n = 12 vs. n = 6). Adherence was poor, with only 11% of patients reporting using the oxygen as prescribed. CONCLUSIONS: Although the study was significantly underpowered, HOT prescribed for 15 hours per day and subsequently used for a mean of 5.4 hours per day has no impact on quality of life as measured by the MLwHF questionnaire score at 6 months. Suggestions for future research include (1) a trial of patients with severe heart failure randomised to have emergency oxygen supply in the house, supplied by cylinders rather than an oxygen concentrator, powered to detect a reduction in admissions to hospital, and (2) a study of bed-bound patients with heart failure who are in the last few weeks of life, powered to detect changes in symptom severity. TRIAL REGISTRATION: Current Controlled Trials ISRCTN60260702. FUNDING: This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 19, No. 75. See the NIHR Journals Library website for further project information.