Assessing Exposure to Household Air Pollution: A Systematic Review and Pooled Analysis of Carbon Monoxide as a Surrogate Measure of Particulate Matter

BACKGROUND

Household air pollution from solid fuel burning is a leading contributor to disease burden globally. Fine particulate matter (PM_2.5) is thought to be responsible for many of these health impacts. A co-pollutant, carbon monoxide (CO) has been widely used as a surrogate measure of PM_2.5 in studies of household air pollution.

OBJECTIVE

The goal was to evaluate the validity of exposure to CO as a surrogate of exposure to PM_2.5 in studies of household air pollution and the consistency of the PM_2.5-CO relationship across different study settings and conditions.

METHODS

We conducted a systematic review of studies with exposure and/or cooking area PM_2.5 and CO measurements and assembled 2,048 PM_2.5 and CO measurements from a subset of studies (18 cooking area studies and 9 personal exposure studies) retained in the systematic review. We conducted pooled multivariate analyses of PM_2.5-CO associations, evaluating fuels, urbanicity, season, study, and CO methods as covariates and effect modifiers.

RESULTS

We retained 61 of 70 studies for review, representing 27 countries. Reported PM_2.5-CO correlations (r) were lower for personal exposure (range: 0.22-0.97; median=0.57) than for cooking areas (range: 0.10-0.96; median=0.71). In the pooled analyses of personal exposure and cooking area concentrations, the variation in ln(CO) explained 13% and 48% of the variation in ln(PM_2.5), respectively.

CONCLUSIONS

Our results suggest that exposure to CO is not a consistently valid surrogate measure of exposure to PM_2.5. Studies measuring CO exposure as a surrogate measure of PM exposure should conduct local validation studies for different stove/fuel types and seasons. https://doi.org/10.1289/EHP767.

A panel study of the acute effects of personal exposure to household air pollution on ambulatory blood pressure in rural Indian women

BACKGROUND

Almost half the world's population is exposed to household air pollution from biomass and coal combustion. The acute effects of household air pollution on the cardiovascular system are poorly characterized. We conducted a panel study of rural Indian women to assess whether personal exposures to black carbon during cooking were associated with acute changes in blood pressure.

METHODS

We enrolled 45 women (ages 25-66 years) who cooked with biomass fuels. During cooking sessions in winter and summer, we simultaneously measured their personal real-time exposure to black carbon and conducted ambulatory blood pressure measurements every 10min. We recorded ambient temperature and participants' activities while cooking. We assessed body mass index, socioeconomic status, and salt intake. Multivariate mixed effects regression models with random intercepts were used to estimate the associations between blood pressure and black carbon exposure, e.g., average exposure in the minutes preceding blood pressure measurement, and average exposure over an entire cooking session.

RESULTS

Women's geometric mean (GM) exposure to black carbon during cooking sessions was lower in winter (GM: 40μg/m(3); 95% CI: 30, 53) than in summer (GM: 56μg/m(3); 95% CI: 42, 76). Interquartile range increases in black carbon were associated with changes in systolic blood pressure from -0.4mm Hg (95% CI: -2.3, 1.5) to 1.9mm Hg (95% CI: -0.8, 4.7), with associations increasing in magnitude as black carbon values were assessed over greater time periods preceding blood pressure measurement. Interquartile range increases in black carbon were associated with small decreases in diastolic blood pressure from -0.9mm Hg (95% CI: -1.7, -0.1) to -0.4mm Hg (95% CI: -1.6, 0.8). Associations of a similar magnitude were estimated for cooking session-averaged values.

CONCLUSIONS

We found some evidence of an association between exposure to black carbon and acute increases in systolic blood pressure in Indian women cooking with biomass fuels, which may have implications for the development of cardiovascular diseases.

A population-based comparison of the use of acute healthcare services by older adults with and without mental illness diagnoses

Older adults with mental illness (MI) are a highly vulnerable population and need to be provided healthcare services in a timely and thorough way. Compared with older adults without MI, older adults with MI spend a great deal of time being hospitalized and hence costing millions of dollars because the care they need is often overlooked and/or not provided. While they end up spending too much time in hospital, in the emergency department and getting readmitted to hospital because of their MI, this could have been prevented or lessened if an adequate assessment and treatment regime was done by clinicians who were well informed on the topic of older adults' mental health. Older adults with MI are also more likely to leave hospital for long-term care settings, to die and to have more sickness compared with older adults who do not have MI. Further, they are also more likely to be admitted to hospital on an urgent, unplanned basis. How older adults with MI use acute hospitals is important for psychiatric nurses to know and understand, as they can help to provide the care needed so they do not have to be in hospital for long periods of time. Psychiatric nurses can share much support and information on making sure older adults with MI are accurately care for when needed. To explore and compare predictors of hospital length of stay (LOS), acute LOS (ALOS), emergency room (ER) wait times, rate of readmission (ROR) and costs of inpatient hospital care for older adults with and without mental illness (MI) diagnoses in the province of Newfoundland and Labrador (NL). This descriptive-comparative study used aggregate population level data of 12,283 people aged 65 years and older admitted to an acute care hospital in the province of NL. A total of 8.3% of hospitalized older adults had MI diagnoses. Older adults with MI diagnoses had a significantly longer LOS, ALOS, ROR, ER wait time and costs compared with older adults without MI diagnoses, after controlling for medical co-morbidities. Key variables such as patient demographics, admission indicators, discharge indicators and other medical co-morbidities had differential impacts on observed service use. While only a small percentage of hospitalized older adults had MI diagnoses, the use and cost of acute hospitalizations was significantly greater than that of older adults without MI diagnoses.

Elevated phenylacetic acid levels do not correlate with adverse events in patients with urea cycle disorders or hepatic encephalopathy and can be predicted based on the plasma PAA to PAGN ratio

BACKGROUND

Phenylacetic acid (PAA) is the active moiety in sodium phenylbutyrate (NaPBA) and glycerol phenylbutyrate (GPB, HPN-100). Both are approved for treatment of urea cycle disorders (UCDs) - rare genetic disorders characterized by hyperammonemia. PAA is conjugated with glutamine in the liver to form phenylacetyleglutamine (PAGN), which is excreted in urine. PAA plasma levels ≥ 500 μg/dL have been reported to be associated with reversible neurological adverse events (AEs) in cancer patients receiving PAA intravenously. Therefore, we have investigated the relationship between PAA levels and neurological AEs in patients treated with these PAA pro-drugs as well as approaches to identifying patients most likely to experience high PAA levels.

METHODS

The relationship between nervous system AEs, PAA levels and the ratio of plasma PAA to PAGN were examined in 4683 blood samples taken serially from: [1] healthy adults [2], UCD patients of ≥ 2 months of age, and [3] patients with cirrhosis and hepatic encephalopathy (HE). The plasma ratio of PAA to PAGN was analyzed with respect to its utility in identifying patients at risk of high PAA values.

RESULTS

Only 0.2% (11) of 4683 samples exceeded 500 μg/ml. There was no relationship between neurological AEs and PAA levels in UCD or HE patients, but transient AEs including headache and nausea that correlated with PAA levels were observed in healthy adults. Irrespective of population, a curvilinear relationship was observed between PAA levels and the plasma PAA:PAGN ratio, and a ratio>2.5 (both in μg/mL) in a random blood draw identified patients at risk for PAA levels>500 μg/ml.

CONCLUSIONS

The presence of a relationship between PAA levels and reversible AEs in healthy adults but not in UCD or HE patients may reflect intrinsic differences among the populations and/or metabolic adaptation with continued dosing. The plasma PAA:PAGN ratio is a functional measure of the rate of PAA metabolism and represents a useful dosing biomarker.

A STUDY OF PNEUMOCOCCI AND ALLIED ORGANISMS IN HUMAN MOUTHS AND LUNGS AFTER DEATH

THE FOLLOWING CONCLUSIONS MAY BE DRAWN, BASED UPON THE RESULT OF OUR RESEARCHES: 1. Organisms of the pneumococcus or streptococcus group are present in the lungs of practically all cases, whether normal or showing a variety of lesions; strictly speaking, they were found by us in forty out of forty-two cases, or in 95% of our series. 2. The pneumococci and the streptococci were obtained in practically similar percentages-that is, in 50 % of the cases. 3. Pneumococci were not obtained more frequently in the small series of patients exposed for some time to hospital atmosphere; our tables show the contrary to obtain. The number of cases examined were, however, insufficient, and the findings may thus be accidental, and hence of no value. 4. Test micro-organisms, namely, small portions-half a drachm or less-of B. prodigiosus, introduced into the human mouth after death, were conveyed to and recovered from the lungs by culture in a little over half of the cases in which this experiment was tried. The test micro-organisms are, we believe, conveyed to the lungs with the fluid which collects in mouths of persons after death, and which in many cases collects just before death. The numerous manipulations entailed in the removal of the body from the wards to the morgue greatly facilitate the entrance of any fluid from the pharynx and buccal cavity into the lungs. It follows logically, from the results obtained in this experiment, that the cultural findings after death are no guide to the bacterial contents of the lungs during life, and that any deductions made from such findings are unreliable and deceptive. Granted that our explanation be correct, there is every reason to believe that any of the micro-organisms present in the mouths and pharynx and in many cases in the stomach contents may enter the lungs and, if the conditions be suitable, increase in numbers, during the time between death and the examination of the lungs. There exists, perhaps, more frequently than has hitherto been suspected, a series of diplococci, intermediate between the typical pneumococci and streptococci. The diplococci of this type have been found in forty (40) per cent. of our cases. The differential diagnosis of these atypical diplococci from the pneumococci and streptococci is a difficult one, depending, as it does, upon general cultural characteristics. No single character, such as the presence of capsules or the fermentation of inulin, virulence, etc., has been found to be a certain criterion. The few agglutinative reactions we have made seem to show that these intermediate diplococci, those of Groups II, III, and IV, have no or only slight agglutinative affinities to the typical pneumococcus. Further tests must, however, be made with the various methods at our disposal before this statement can be accepted as final. These diplococci are of interest from the fact that they have been found in the blood during life, and in the pial exudate of cases of meningitis, endocarditis, etc. 6. Our studies have thrown no light whatever upon the conditions which determine the onset of lobar pneumonia in apparently healthy persons. Moreover, we have been unable to draw conclusions as to the presence of pneumococci in the lungs during life, or as to the channels by which they gain access thereto.

"RED-LEG"-AN INFECTIOUS DISEASE OF FROGS

The epidemics we have observed, were due to the presence and growth in the frogs of Bacillus hydrophilus fuscus. This was proved by recovering the bacillus in pure culture from the body fluids of frogs sick or dead of the disease, and the inoculation of healthy frogs with an emulsion of the pure culture, and by obtaining the same clinical picture and pathological findings as in the original diseased frogs; and, finally, by recovering the bacillus in pure culture from frogs inoculated and sick or dying as a result of the inoculation. The disease is widely distributed throughout North America and Europe, and in this country and Canada is known as "red-leg." It has been observed by us chiefly in the warm weather of September and October. The disease is characterized by congestion of the ventral surfaces of the body, with more or less ulceration in, and hæmorrhage beneath, the skin, bloating due to serous exudation into the lymph sacs, gradual failure to respond to stimuli, which symptoms are followed by coma and death, the last being occasionally preceded by tetanic seizures. After death hæmorrhages into the muscles and degenerative changes in the muscles, spleen, liver, and, to a slight degree, in the intestinal tract, are found. The blood shows an advanced degree of anæmia and leucocytosis. Predisposing causes of the disease are lesions of the skin, which seem to be the usual portal of entry of the infection, and lowered resistance from heat and from anæmia. By a series of controlled experiments with inoculated frogs we have shown that, while temperatures a little above freezing have no harmful effect upon the frogs, they completely control all manifestations of the disease in inoculated or diseased frogs, if the frogs are left in the cold for a period as long as seven days; and, further, that even short periods in the cold chamber will bring about a delay of the fatal results in diseased or inoculated frogs. The anæmia so often found in apparently healthy frogs seems in many cases to be due to the presence in the lungs of the frog of a parasite, the Distomum cylindraceum, which, occurring in sufficiently large numbers in an individual frog, is capable of materially diminishing the available supply of red corpuscles. Severe laking of the blood, the presence of numerous isolated red-cell nuclei, and great diminution in the number, or almost total absence of the red cells in the diseased frogs, are in proportion to the severity of the infection and due to bacterial action. The presence of the hæmatozoan parasite, the Drepanidium, does not play any part as a predisposing or exciting cause of the disease. The ascarid Rhabdomena nigrovenosum, although frequently present as a parasite in the lungs of the frogs, plays no part in causing or promoting the disease.

Rapeseed cytoplasm gives advantage in wild relatives and complicates genetically modified crop biocontainment

Biocontainment methods for genetically modified crops closest to commercial reality (chloroplast transformation, male sterility) would be compromised (in absolute terms) by seed-mediated gene flow leading to chloroplast capture. Even in these circumstances, however, it can be argued that biocontainment still represses transgene movement, with the efficacy depending on the relative frequency of seed- and pollen-mediated gene flow. In this study, we screened for crop-specific chloroplast markers from rapeseed (Brassica napus) amongst sympatric and allopatric populations of wild B. oleracea in natural cliff-top populations and B. rapa in riverside and weedy populations. We found only modest crop chloroplast presence in wild B. oleracea and in weedy B. rapa, but a surprisingly high incidence in sympatric (but not in allopatric) riverside B. rapa populations. Chloroplast inheritance models indicate that elevated crop chloroplast acquisition is best explained if crop cytoplasm confers selective advantage in riverside B. rapa populations. Our results therefore imply that chloroplast transformation may slow transgene recruitment in two settings, but actually accelerate transgene spread in a third. This finding suggests that the appropriateness of chloroplast transformation for biocontainment policy depends on both context and geographical location.

Swallowing function after intensity modulated radiotherapy (IMRT) and chemotherapy for head and neck cancer

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Background: To evaluate the swallowing function of patients treated with intensity modulated radiation therapy (IMRT) + chemotherapy (CT) for HNSCC. Methods: Patients completing RT between 9/04 and 8/06 at the DFCI/BWH were evaluated with IRB approval. All patients had formal swallowing evaluation following the completion of therapy; patients with swallowing difficulty underwent video swallow and both stricture and aspiration were scored. Variables examined for correlation with swallowing pathology were: age, race, gender, smoking and alcohol history, primary site, LVI, PNI, RT intention (primary, postop) and use of induction CT. All variables were analyzed via two-sided t-test. Results: 96 patients were evaluated. Median follow-up 10 mos. 75% of the pts were given definitive RT and 25% received postop RT. 72% stage IV, 24% stage III. Primary sites: oropharynx-43, hypopharynx/larynx-17, oral cavity-13, nasopharynx-11, maxillary sinus-2 and unknown primary-10 pts. All pts received once daily IMRT. 9 pts received RT alone, 28 pts received sequential induction and concurrent (CT) and 59 pts received concurrent CT. 31 pts (32%) had some aspiration after therapy; 36 pts (37%) had evidence of a stricture following RT. All but 5 patients had percutaneous endoscopic gastrostomy placed prophylactically RT. Smoking history was the only significant factor found on univariate analysis to correlate with stricture (p=0.05) but not aspiration. Induction CT was not a significant factor in causing aspiration or stricture. 22 of the strictures (71%) resolved after dilation. RT doses to swallowing structures are under evaluation and will be presented. Conclusions: Aspiration and stricture are common side effects after radical treatment with IMRT and CT for HNSCC. Smoking has a significant negative impact on functional outcome.

No significant financial relationships to disclose.