Household carbon monoxide (CO) concentrations in a large African city: An unquantified public health burden?

Carbon monoxide (CO) is a poisonous gas produced by incomplete combustion of carbon-based fuels that is linked to mortality and morbidity. Household air pollution from burning fuels on poorly ventilated stoves can lead to high concentrations of CO in homes. There are few datasets available on household concentrations of CO in urban areas of sub-Saharan African countries. CO was measured every minute over 24 h in a sample of homes in Nairobi, Kenya. Data on household characteristics were gathered by questionnaire. Metrics of exposure were summarised and analysis of temporal changes in concentration was performed. Continuous 24-h data were available from 138 homes. The mean (SD), median (IQR) and maximum 24-h CO concentration was 4.9 (6.4), 2.8 (1.0-6.3) and 44 ppm, respectively. 50% of homes had detectable CO concentrations for 847 min (14h07m) or longer during the 24-h period, and 9% of homes would have activated a CO-alarm operating to European specifications. An association between a metric of total CO exposure and self-reported exposure to vapours >15 h per week was identified, however this were not statistically significant after adjustment for the multiple comparisons performed. Mean concentrations were broadly similar in homes from a more affluent area and an informal settlement. A model of typical exposure suggests that cooking is likely to be responsible for approximately 60% of the CO exposure of Nairobi schoolchildren. Household CO concentrations are substantial in Nairobi, Kenya, despite most homes using gas or liquid fuels. Concentrations tend to be highest during the evening, probably associated with periods of cooking. Household air pollution from cooking is the main source of CO exposure of Nairobi schoolchildren. The public health impacts of long-term CO exposure in cities in sub-Saharan Africa may be considerable and should be studied further.

Investigating causal relationships between genetically determined increased risk of attention-deficit/hyperactivity disorder (ADHD) and atopic dermatitis (AD): A Mendelian randomization analysis

Atopic dermatitis (AD) is a chronic, inflammatory skin condition with a huge disease burden. Attention-deficit/hyperactivity disorder (ADHD) is often diagnosed in children, and is associated with symptoms of inattention, hyperactivity and impulsive behaviour. Observational studies have demonstrated associations between AD and ADHD. However, to date, there has been no formal assessment of causal relationship between the two. We aim to evaluate causal relationships between genetically increased risk of AD and ADHD using Mendelian randomization (MR) approach. Two-sample bi-directional MR was conducted to elucidate potential causal relationships between genetically increased risk of AD and ADHD, using the largest and most recent genome-wide association study datasets for AD and ADHD-EArly Genetics & Lifecourse Epidemiology AD consortium (21 399 cases and 95 464 controls) and Psychiatric Genomics Consortium (20 183 cases and 35 191 controls). Genetically determined increased risk of AD is not associated with ADHD based on genetic information: odds ratio (OR) of 1.02 (95% CI -0.93 to 1.11; p = 0.705). Similarly, genetic determined increased risk of ADHD is not associated with an increased risk of AD: OR of 0.90 (95% CI -0.76 to 1.07; p = 0.236). Horizontal pleiotropy was not observed from the MR-Egger intercept test (p = 0.328) Current MR analysis showed no causal relationship between genetically increased risk of AD and ADHD in either direction in individuals of European descent. Any observed associations between AD and ADHD in previous population studies could possibly be due to confounding lifestyle factors such as psychosocial stress and sleeping habits.

Healthcare-acquired clusters of COVID-19 across multiple wards in a Scottish health board

Background

Healthcare-acquired COVID-19 has been an additional burden on hospitals managing increasing numbers of patients with SARS-CoV-2. One acute hospital (W) among three in a Scottish healthboard experienced an unexpected surge of COVID-19 clusters.

Aim

To investigate possible causes of COVID-19 clusters at Hospital W.

Methods

Daily surveillance provided total numbers of patients and staff involved in clusters in three acute hospitals (H, M and W) and care homes across the healthboard. All clusters were investigated and documented, along with patient boarding, community infection rates and outdoor temperatures from October 2020 to March 2021. Selected SARS-CoV-2 strains were genotyped.

Findings

There were 19 COVID-19 clusters on 14 wards at Hospital W during the six-month study period, lasting from two to 42 days (average, five days; median, 14 days) and involving an average of nine patients (range 1–24) and seven staff (range 0–17). COVID-19 clusters in Hospitals H and M reflected community infection rates. An outbreak management team implemented a control package including daily surveillance; ward closures; universal masking; screening; restricting staff and patient movement; enhanced cleaning; and improved ventilation. Forty clusters occurred across all three hospitals before a January window-opening policy, after which there were three during the remainder of the study.

Conclusion

The winter surge of COVID-19 clusters was multi-factorial, but clearly exacerbated by moving trauma patients around the hospital. An extended infection prevention and control package including enhanced natural ventilation helped reduce COVID-19 clusters in acute hospitals.

Sex modifies the association between body mass index and carotid artery intima media thickness in the multi-ethnic Singapore population

Background and aims

Globally cardiovascular disease (CVD) risk is higher in men than in women in the younger age group but the risk is attenuated in later life with an unexpected higher risk in women in some populations. A better understanding of sex differences in CVD is needed. Carotid artery intima-media thickness (CIMT) has been proposed for CVD risk assessment in individuals at intermediate risk. We study the gender interactions in the associations of the traditional cardiovascular risk factors with CIMT.

Methods

We performed carotid ultrasonography in the large population health study-HELIOS conducted in Singapore. Measurements were performed as per Mannheim consensus, at the far wall of bilateral common carotid artery at 8 sites in each participant. We report the average of all measurements (avgCIMT) and maximum value (maxCIMT). We analysed 2061 healthy participants recruited between 2018–2020. Inclusion criteria for this analysis: non-smokers, not known to have diabetes, hypertension, hyperlipidemia or ischemic heart disease. Individuals with systolic blood pressure >160 mm Hg or fasting glucose >7.0 mmol/L on recruitment were excluded. Multivariable linear regression analysis was performed to examine the association between CIMT and cardiovascular risk factors in the healthy population adjusting for age, sex and ethnicity. All analysis was performed using Stata version 16.0.

Results

After exclusion, 1407 healthy participants were included in the analysis. Median (IQR) avgCIMT: 0.56 (0.50, 0.65) in men; 0.54 (0.50, 0.58) in women. Median (IQR) maxCIMT: 0.64 (0.57, 0.76) in men; 0.61 (0.54, 0.70) in women. The avgCIMT and the maxCIMT were higher in males when compared to women and all traditional cardiovascular risk factors associated with CIMT after adjustment for age, sex and ethnicity (P<0.05) (Table 1). Interaction tests in multivariable model adjusted for age, ethnicity, pulse pressure, non HDL-C and HbA1c showed a significant interaction between sex and body mass index (BMI) with predicted effects on avgCIMT and maxCIMT being relatively higher in males at the same BMI when compared to females (P-interaction <0.01) (Figure 1).

Conclusion

Sex modifies the relationship between BMI and CIMT in Singapore's multi-ethnic population. Understanding the intermediary mechanisms involved will help in developing personalized preventive strategies.

Funding Acknowledgement

Type of funding sources: None. Figure 1

Ambient particulate matter and biomass burning: an ecological time series study of respiratory and cardiovascular hospital visits in northern Thailand

BACKGROUND

Exposure to particulate matter (PM) emitted from biomass burning is an increasing concern, particularly in Southeast Asia. It is not yet clear how the source of PM influences the risk of an adverse health outcome. The objective of this study was to quantify and compare health risks of PM from biomass burning and non-biomass burning sources in northern Thailand.

METHODS

We collected ambient air pollutant data (PM with a diameter of < 10 μm [PM10], PM2.5, Carbon Monoxide [CO], Ozone [O3], and Nitrogen Dioxide [NO2]) from ground-based monitors and daily outpatient hospital visits in Thailand during 2014-2017. Outpatient data included chronic lower respiratory disease (CLRD), ischaemic heart disease (IHD), and cerebrovascular disease (CBVD). We performed an ecological time series analysis to evaluate the association between daily air pollutants and outpatient visits. We used the 90th and 95th percentiles of PM10 concentrations to determine days of exposure to PM predominantly from biomass burning.

RESULTS

There was significant intra annual variation in PM10 levels, with the highest concentrations occurring during March, coinciding with peak biomass burning. Incidence Rate Ratios (IRRs) between daily PM10 and outpatient visits were elevated most on the same day as exposure for CLRD = 1.020 (95% CI: 1.012 to 1.028) and CBVD = 1.020 (95% CI: 1.004 to 1.035), with no association with IHD = 0.994 (95% CI: 0.974 to 1.014). Adjusting for CO tended to increase effect estimates. We did not find evidence of an exposure response relationship with levels of PM10 on days of biomass burning.

CONCLUSIONS

We found same-day exposures of PM10 to be associated with certain respiratory and cardiovascular outpatient visits. We advise implementing measures to reduce population exposures to PM wherever possible, and to improve understanding of health effects associated with burning specific types of biomass in areas where such large-scale activities occur.

Impact of type 2 diabetes on hospitalization and mortality in people with malignancy

AIM

To compare the characteristics of and outcomes for people with malignancies with and without a co-diagnosis of diabetes.

METHODS

Emergency department and hospital discharge data from a single centre for the period between 1 January 2015 and 31 December 2017 were used to identify people with a diagnosis of a malignancy and diabetes. Multivariate Cox regression models were used to estimate the effect of diabetes on all-cause mortality. A truncated negative binomial regression model was used to assess the impact of diabetes on length of hospital inpatient stay. Prentice-Williams-Peterson total time models were used to assess the effect of diabetes on number of emergency department re-presentations and inpatient re-admissions.

RESULTS

Of 7004 people identified with malignancies, 1195 (17.1%) were also diagnosed with diabetes. A diagnosis of diabetes was associated with a greater number of inpatient re-admissions [adjusted hazard ratio 1.13 (95% CI 1.03, 1.24)], a greater number of emergency department re-presentations [adjusted hazard ratio 1.13 (95% CI 1.05, 1.22)] and longer length of stay [adjusted incidence rate ratio 1.14 (95% CI 1.04, 1.25)]. A co-diagnosis of diabetes was also associated with a 48% increased risk of all-cause mortality [adjusted hazard ratio 1.48 (95% CI 1.22-1.76)].

CONCLUSIONS

People with malignancies and diabetes had significantly more emergency department presentations, more inpatient admissions, longer length of hospital stay and higher rates of all-cause mortality compared to people with a malignancy without diabetes.

Association of size-fractionated indoor particulate matter and black carbon with heart rate variability in healthy elderly women in Beijing

Associations between size-fractionated indoor particulate matter (PM) and black carbon (BC) and heart rate variability (HRV) and heart rate (HR) in elderly women remain unclear. Twenty-nine healthy elderly women were measured for 24-hour HRV/HR indices. Real-time size-fractionated indoor PM and BC were monitored on the same day and on the preceding day. Mixed-effects models were applied to investigate the associations between pollutants and HRV/HR indices. Increases in size-fractionated indoor PM were significantly associated with declines in power in the high-frequency band (HF), power in the low-frequency band (LF), and standard deviation of all NN intervals (SDNN). The largest decline in HF was 19% at 5-minute moving average for an interquartile range (IQR) increase (24 μg/m³ ) in PM_0.5 . The results showed that smaller particles could lead to greater reductions in HRV indices. The reported associations were modified by body mass index (BMI): Declines in HF at 5-minute average for an IQR increase in PM_0.5 were 34.5% and 1.0% for overweight (BMI ≥25 kg/m² ) and normal-weight (BMI <25 kg/m² ) participants, respectively. Moreover, negative associations between BC and HRV indices were found to be significant in overweight participants. Increases in size-fractionated indoor PM and BC were associated with compromised cardiac autonomic function in healthy elderly women, especially overweight ones.

Indoor inhalation intake fractions of fine particulate matter: review of influencing factors

Exposure to fine particulate matter (PM_2.5 ) is a major contributor to the global human disease burden. The indoor environment is of particular importance when considering the health effects associated with PM_2.5 exposures because people spend the majority of their time indoors and PM_2.5 exposures per unit mass emitted indoors are two to three orders of magnitude larger than exposures to outdoor emissions. Variability in indoor PM_2.5 intake fraction (iF_in,total ), which is defined as the integrated cumulative intake of PM_2.5 per unit of emission, is driven by a combination of building-specific, human-specific, and pollutant-specific factors. Due to a limited availability of data characterizing these factors, however, indoor emissions and intake of PM_2.5 are not commonly considered when evaluating the environmental performance of product life cycles. With the aim of addressing this barrier, a literature review was conducted and data characterizing factors influencing iF_in,total were compiled. In addition to providing data for the calculation of iF_in,total in various indoor environments and for a range of geographic regions, this paper discusses remaining limitations to the incorporation of PM_2.5 -derived health impacts into life cycle assessments and makes recommendations regarding future research.

Use of dust fall filters as passive samplers for metal concentrations in air for communities near contaminated mine tailings

Mine tailings are a source of metal exposures in many rural communities. Multiple air samples are necessary to assess the extent of exposures and factors contributing to these exposures. However, air sampling equipment is costly and requires trained personnel to obtain measurements, limiting the number of samples that can be collected. Simple, low-cost methods are needed to allow for increased sample collection. The objective of our study was to assess if dust fall filters can serve as passive air samplers and be used to characterize potential exposures in a community near contaminated mine tailings. We placed filters in cylinders, concurrently with active indoor air samplers, in 10 occupied homes. We calculated an estimated flow rate by dividing the mass on each dust fall filter by the bulk air concentration and the sampling duration. The mean estimated flow rate for dust fall filters was significantly different during sampling periods with precipitation. The estimated flow rate was used to estimate metal concentration in the air of these homes, as well as in 31 additional homes in another rural community impacted by contaminated mine tailings. The estimated air concentrations had a significant linear association with the measured air concentrations for beryllium, manganese and arsenic (p < 0.05), whose primary source in indoor air is resuspended soil from outdoors. In the second rural community, our estimated metal concentrations in air were comparable to active air sampling measurements taken previously. This passive air sampler is a simple low-cost method to assess potential exposures near contaminated mining sites.

Z-velocity in screening for intrauterine growth restriction

OBJECTIVES

Ultrasound scans provide the basis for detection of intrauterine growth restriction (IUGR) but often fail to distinguish IUGR from small-for-gestational age (SGA) fetuses. This study introduces the concept of Z-velocity, calculated as changes in Z-scores over time, as an additional criterion in the diagnosis of IUGR.

METHODS

A computer program simulated 50 000 fetal abdominal circumference (FAC) scans based on published growth formulae. False-positive rates were calculated to determine optimal scan time and scan intervals. Using an independent simulation of 32 500 FAC scans, the two methods were compared using receiver-operating characteristics (ROC) curve analysis.

RESULTS

ROC showed areas under the curve of > 0.74 over the complete range of scan intervals. The positive predictive value of growth arrest as the only diagnostic criterion was, however, too low to recommend it as an exclusive or the first diagnostic criterion.

CONCLUSIONS

Z-velocity can be used to decide whether further investigations for growth abnormality are required in fetuses that fall below the 10(th) percentile. The gain of combined diagnostic approaches should be calculated from large databases that include the neonatal ponderal index as the gold standard.

Outcome of very premature infants with necrotising enterocolitis cared for in centres with or without on site surgical facilities

OBJECTIVE

To determine if the presence of a neonatal surgical facility on site has any effect on mortality and morbidity of very premature infants with necrotising enterocolitis (NEC).

DESIGN AND SETTING

Retrospective review of infants of less than 29 weeks gestation cared for in the seven perinatal centres in New South Wales.

PATIENTS

Between 1992 and 1997, 605 infants were cared for in two centres with in house surgical facilities (group 1) and 1195 in five centres where transfers were required for surgical management (group 2).

RESULTS

Although use of antenatal steroids was significantly lower in group 1 centres than group 2 centres (74% v. 85% respectively), and the incidence of hyaline membrane disease, pneumothorax, and NEC was higher, mortality was identical (27%). Fifty two (9%) infants in group 1 and 72 (6%) in group 2 of comparable perinatal characteristics and CRIB (Clinical Risk Index for Babies) scores developed radiologically or pathologically proven NEC. The overall mortality of infants with NEC in group 1 was lower but this was not statistically significant (27% v. 35%). Significantly more infants with NEC in group 1 had surgery (69% v. 39%). There were fewer postoperative deaths in group 1 and more deaths without surgery in group 2. The duration of respiratory and nutritional support and hospital stay for the survivors were similar in the two groups. In a multivariate analysis, shorter gestation was the only factor associated with mortality in infants with NEC; the presence of in house surgical facilities was not.

CONCLUSIONS

There were no significant differences in outcome of premature infants with NEC managed in perinatal centres with or without on site surgical facilities. Early transfers should be encouraged. This finding may have implications for future planning of facilities for neonatal care.

Haploinsufficiency of CBFA2 causes familial thrombocytopenia with propensity to develop acute myelogenous leukaemia

Familial platelet disorder with predisposition to acute myelogenous leukaemia (FPD/AML, MIM 601399) is an autosomal dominant disorder characterized by qualitative and quantitative platelet defects, and propensity to develop acute myelogenous leukaemia (AML). Informative recombination events in 6 FPD/AML pedigrees with evidence of linkage to markers on chromosome 21q identified an 880-kb interval containing the disease gene. Mutational analysis of regional candidate genes showed nonsense mutations or intragenic deletion of one allele of the haematopoietic transcription factor CBFA2 (formerly AML1) that co-segregated with the disease in four FPD/AML pedigrees. We identified heterozygous CBFA2 missense mutations that co-segregated with the disease in the remaining two FPD/AML pedigrees at phylogenetically conserved amino acids R166 and R201, respectively. Analysis of bone marrow or peripheral blood cells from affected FPD/AML individuals showed a decrement in megakaryocyte colony formation, demonstrating that CBFA2 dosage affects megakaryopoiesis. Our findings support a model for FPD/AML in which haploinsufficiency of CBFA2 causes an autosomal dominant congenital platelet defect and predisposes to the acquisition of additional mutations that cause leukaemia.

Congenital fibrosarcoma of the upper extremity

Congenital or infantile fibrosarcoma is a rare soft-tissue neoplasm that should be considered in the differential diagnosis of a large extremity mass presenting at birth. These tumors are notoriously misdiagnosed at birth as either hemangiomas or lymphatic malformations. Definitive diagnosis is made by physical examination, special radiologic studies, and biopsy. Although histologically similar to fibrosarcomas occurring in adults, the congenital lesions differ in their clinical behavior; metastases are rare, local recurrence is common, and the prognosis is good with wide local excision combined with chemotherapy. Amputation should be reserved for chemoresistant patients in whom the involvement of neurovascular structures by the tumor make a limb-sparing aggressive excision impossible.

Human early pregnancy factor and early pregnancy associated protein before and after therapeutic abortion in comparison with beta-hCG, estradiol, progesterone and 17-hydroxyprogesterone

Serum activities and concentrations, respectively, of early pregnancy factor (EPF), early pregnancy associated protein (EPAP), beta-hCG, estradiol, progesterone and 17-hydroxyprogesterone were estimated in 20 healthy primigravidae within the tenth to twelfth completed gestational week before and after therapeutic abortion. EPF, beta-hCG and estradiol markedly decreased after termination of pregnancy, whereas progesterone and 17-hydroxyprogesterone concentrations moderately fell. EPAP showed no significant alterations in a 24 hours period. Because of its possible role as immunosuppressive substance and its short half-life EPF may be a promising immunobiomarker for disturbances in early pregnancy.

Human early pregnancy factor: serum concentrations before and after therapeutic abortion in comparison with beta-hCG and an early pregnancy associated protein

Serum concentrations of the early pregnancy factor (EPF), beta-hCG and the early pregnancy associated protein (EPAP) were measured in 12 patients before and after therapeutic abortion for social-medical reasons. Detection of EPF was performed by the rosette-inhibition assay, beta-hCG quantification by radioimmunoassay and EPAP measurements by rocket immunoelectrophoresis using a monospecific polyclonal rabbit antiserum. The disappearance rate of EPF after termination of pregnancy was closely correlated with the decrease of beta-hCG concentrations (rpbis = 0.71) and loosely correlated with the decrease of EPAP concentrations (rPbis = 0.43). No correlation has been found between hCG and EPAP values.

Detection of early pregnancy factor (EPF) in pregnant and nonpregnant subjects with the rosette inhibition test

We tested for early pregnancy factor (EPF) using a rosette inhibition test with polyclonal anti-lymphocyte serum from the horse and two monoclonal antibodies specific for the E-receptor of T-lymphocytes. When lymphocytes were preincubated with early human pregnancy sera, rosette inhibition titres were four or more dilutions higher (P less than 0.01) than when lymphocytes were preincubated with nonpregnant sera.

[Significance of the detection of early pregnancy factor for monitoring normal and disordered early pregnancy]

In twenty patients with the tentative diagnosis of disturbed early pregnancy, the early pregnancy factor (EPF) was estimated by means of the rosette inhibition test and the early pregnancy associated protein (EPAP) by rocket-immunoelectrophoresis. The results were compared with hCG concentrations in the urine, beta-hCG concentrations in the serum as well as with clinical and sonographical findings. In intact pregnancies, positive EPF values are an additional sign of embryonic viability. Negative EPF values can be an early indicator for pregnancy losses. The diagnosis of an ectopic pregnancy can be confirmed by negative EPF values in spite of elevated hCG levels and uncertain sonographic findings. In cases of missed abortion the EPF estimation was always negative in contrast to other parameters of pregnancy. EPF detection may be helpful to differentiate menstruation disorders and early pregnancy losses. Because of its longer half-life, the EPAP is not such a sensitive parameter for early pregnancy disturbances as the EPF.