Estimating the burden of disease attributable to urban outdoor air pollution in South Africa in 2000

Objectives. To quantify the mortality burden attributed to urban outdoor air pollution in South Africa in 2000. Design. The study followed comparative risk assessment (CRA) methodology developed by the World Heath Organization (WHO). In most urban areas, annual mean concentrations of particulate matter (PM) with diameters less than 10 μm (PM10) from monitoring network data and PM with diameters less than 2.5 μm (PM2.5) derived using a ratio method were weighted according to population size. PM10 and PM2.5 data from air-quality assessment studies in areas not covered by the network were also included. Population-attributable fractions calculated using risk coefficients presented in the WHO study were weighted by the proportion of the total population (33%) in urban environments, and applied to revised estimates of deaths and years of life lost (YLLs) for South Africa in 2000. Setting. South Africa. Subjects. Children under 5 years and adults 30 years and older. Outcome measures. Mortality and YLLs from lung cancer and cardiopulmonary disease in adults (30 years and older), and from acute respiratory infections (ARIs) in children aged 0 - 4 years. Results. Outdoor air pollution in urban areas in South Africa was estimated to cause 3.7% of the national mortality from cardiopulmonary disease and 5.1% of mortality attributable to cancers of the trachea, bronchus and lung in adults aged 30 years and older, and 1.1% of mortality from ARIs in children under 5 years of age. This amounts to 4 637 or 0.9% (95% uncertainty interval 0.3 - 1.5%) of all deaths and about 42 000 YLLs, or 0.4% (95% uncertainty interval 0.1 - 0.7%) of all YLLs in persons in South Africa in 2000. Conclusion. Urban air pollution has under-recognised public health impacts in South Africa. Fossil fuel combustion emissions and traffic-related air pollution remain key targets for public health in South Africa. South African Medical Journal Vol. 97 (8) Part 2 2007: pp. 782-79

The burden of disease attributable to sexually transmitted infections in South Africa in 2000

Objectives. To estimate the burden of disease attributable to sexually transmitted infections (STIs) in South Africa, to identify the factors contributing to this burden, and to review successes and failures in reducing this burden. Design. Years of life lost (YLL) and years lived with disability (YLD) were estimated using different approaches for HIV/ AIDS, other STIs and cervical cancer. Burden in respect of HIV/ AIDS was estimated using the ASSA2002 model, and for the other diseases the revised national burden of disease estimates for 2000 based on 1996 cause-of-death data were used. The ASSA2002 model was used to estimate numbers of AIDS deaths under different prevention and treatment scenarios. Setting. South Africa. Outcome measures. Deaths, YLL and disability-adjusted life years (DALYs) associated with HIV/AIDS, other STIs and cervical cancer. Results. STIs accounted for more than 26% of all deaths and over 5 million DALYs in 2000 and over 98% of this burden was due to HIV/AIDS. A combination of social, behavioural and biological conditions contribute to this burden. HIV/AIDS mortality and morbidity are estimated to have increased significantly since 2000, and the future change in this burden is largely dependent on the extent to which antiretroviral treatment and HIV prevention programmes are introduced. 2.5 million AIDS deaths could be prevented by 2015 if high levels of access to antiretroviral treatment are achieved. Conclusion. South Africa faces one of the largest STI epidemics in the world. A multifaceted strategy to prevent and treat STIs is needed, and burden of disease assessments should look beyond the role of ‘unsafe sex' when attributing this disease burden to risk factors. South African Medical Journal Vol. 97 (8) Part 2 2007: pp. 658-66

A high-performance integrated single-photon detector for telecom wavelengths

We have integrated a commercial avalanche photodiode (APD) and the circuitry needed to operate it as a single-photon detector (SPD) onto a single PC-board. At temperatures accessible with Peltier coolers (~200-240K), the PCB-SPD achieves high detection efficiency (DE) at 1308 and 1545 nm with low dark count probability (e.g. ~10-6/bias pulse at DE=20%, 220 K), making it useful for quantum key distribution (QKD). The board generates fast bias pulses, cancels noise transients, amplifies the signals, and sends them to an on-board discriminator. A digital blanking circuit suppresses afterpulsing.Comment: (10 pages, 6 figures

Estimating the burden of disease attributable to childhood and maternal undernutrition in South Africa in 2000

Objectives. To estimate the disease burden attributable to being underweight as an indicator of undernutrition in children under 5 years of age and in pregnant women for the year 2000. Design. World Health Organization comparative risk assessment (CRA) methodology was followed. The 1999 National Food Consumption Survey prevalence of underweight classified in three low weight-for-age categories was compared with standard growth charts to estimate population-attributable fractions for mortality and morbidity outcomes, based on increased risk for each category and applied to revised burden of disease estimates for South Africa in 2000. Maternal underweight, leading to an increased risk of intra-uterine growth retardation and further risk of low birth weight (LBW), was also assessed using the approach adopted by the global assessment. Monte Carlo simulation-modelling techniques were used for the uncertainty analysis. Setting. South Africa. Subjects. Children under 5 years of age and pregnant women. Outcome measures. Mortality and disability-adjusted life years (DALYs) from protein- energy malnutrition and a fraction of those from diarrhoeal disease, pneumonia, malaria, other non- HIV/AIDS infectious and parasitic conditions in children aged 0 - 4 years, and LBW. Results. Among children under 5 years, 11.8% were underweight. In the same age group, 11 808 deaths (95% uncertainty interval 11 100 - 12 642) or 12.3% (95% uncertainty interval 11.5 - 13.1%) were attributable to being underweight. Protein-energy malnutrition contributed 44.7% and diarrhoeal disease 29.6% of the total attributable burden. Childhood and maternal underweight accounted for 2.7% (95% uncertainty interval 2.6 - 2.9%) of all DALYs in South Africa in 2000 and 10.8% (95% uncertainty interval 10.2 - 11.5%) of DALYs in children under 5. Conclusions. The study shows that reduction of the occurrence of underweight would have a substantial impact on child mortality, and also highlights the need to monitor this important indicator of child health. South African Medical Journal Vol. 97 (8) Part 2 2007: pp. 733-73

Promoter methylation of P16, RARβ, E-cadherin, cyclin A1 and cytoglobin in oral cancer: quantitative evaluation using pyrosequencing

Methylation profiling of cancer tissues has identified this mechanism as an important component of carcinogenesis. Epigenetic silencing of tumour suppressor genes through promoter methylation has been investigated by a variety of means, the most recent of which is pyrosequencing. We have investigated quantitative methylation status in oral squamous cell carcinoma patients. Fresh tumour tissue and normal control tissue from resection margin was obtained from 79 consecutive patients undergoing resection of oral squamous cell carcinoma. DNA was extracted and bisulphite treated. PCR primers were designed to amplify 75–200 bp regions of the CpG rich gene promoters of p16, RARβ, E-cadherin, cytoglobin and cyclinA1. Methylation status of 4-5 CpG sites per gene was determined by pyrosequencing. Significant CpG methylation of gene promoters within tumour specimens was found in 28% for p16, 73% for RARβ, 42% for E-cadherin, 65% for cytoglobin and 53% for cyclinA1. Promoter methylation was significantly elevated in tumours compared to normal tissue for p16 (P=0.048), cytoglobin (P=0.002) and cyclin A1 (P=0.001) but not in RARβ (P=0.088) or E-cadherin (P=0.347). Concordant methylation was demonstrated in this tumour series (P=0.03). Significant differences in degree of methylation of individual CpG sites were noted for all genes except RARβ and these differences were in a characteristic pattern that was reproduced between tumour samples. Cyclin A1 promoter methylation showed an inverse trend with histological grade. Promoter methylation analysis using pyrosequencing reveals valuable quantitative data from several CpG sites. In contrast to qualitative data generated from methylation specific PCR, our data demonstrated p16 promoter methylation in a highly tumour specific pattern. Significant tumour specific methylation of cyclin A1 promoter was also seen. Cytoglobin is a novel candidate tumour suppressor gene highly methylated in upper aero-digestive tract squamous cancer

Autocompensating Quantum Cryptography

Quantum cryptographic key distribution (QKD) uses extremely faint light pulses to carry quantum information between two parties (Alice and Bob), allowing them to generate a shared, secret cryptographic key. Autocompensating QKD systems automatically and passively compensate for uncontrolled time dependent variations of the optical fiber properties by coding the information as a differential phase between orthogonally-polarized components of a light pulse sent on a round trip through the fiber, reflected at mid-course using a Faraday mirror. We have built a prototype system based on standard telecom technology that achieves a privacy-amplified bit generation rate of ~1000 bits/s over a 10-km optical fiber link. Quantum cryptography is an example of an application that, by using quantum states of individual particles to represent information, accomplishes a practical task that is impossible using classical means.Comment: 18 pages, 6 figures, 1 table. Submitted to the New Journal of Physic

Psychological impact and acceptability of magnetic resonance imaging and X-ray mammography: the MARIBS Study

BACKGROUND: As part of the Magnetic Resonance Imaging for Breast Screening (MARIBS), Study women with a family history of breast cancer were assessed psychologically to determine the relative psychological impact and acceptability of annual screening using magnetic resonance imaging (MRI) and conventional X-ray mammography (XRM). METHODS: Women were assessed psychologically at baseline (4 weeks before MRI and XRM), immediately before, and immediately after, both MRI and XRM, and at follow-up (6 weeks after the scans). RESULTS: Overall, both procedures were found to be acceptable with high levels of satisfaction (MRI, 96.3% and XRM, 97.7%; NS) and low levels of psychological morbidity throughout, particularly at 6-week follow-up. Low levels of self-reported distress were reported for both procedures (MRI, 13.5% and XRM, 7.8%), although MRI was more distressing (P=0.005). Similarly, higher anticipatory anxiety was reported before MRI than before XRM (P=0.003). Relative to XRM, MRI-related distress was more likely to persist at 6 weeks after the scans in the form of intrusive MRI-related thoughts (P=0.006) and total MRI-related distress (P=0.014). More women stated that they intended to return for XRM (96.3%) than for MRI (88%; P<0.0005). These effects were most marked for the first year of screening, although they were also statistically significant in subsequent years. CONCLUSION: Given the proven benefits of MRI in screening for breast cancer in this population, these data point to the urgent need to provide timely information and support to women undergoing MRI.The national study is supported by a grant from the UK Medical Research Council (G960413

Sendai five years on: reflections on the role of international law in the creation and reduction of disaster risk

This article offers a critical examination of the position of the Sendai Framework for Disaster Risk Reduction 2015-2030 within international law. It is argued that any interrogation into the role of international law must begin not with existing disaster risk reduction (DRR) laws and policies, but rather with an enquiry into the nature of disaster risk and the role of international law in its creation and reduction. It is demonstrated how, while areas such as international human rights law can be utilized to enforce obligations in support of DRR, other areas – in particular international investment law – actively work to undermine DRR efforts. In order for international law to be a productive tool in the reduction of disaster risk international lawyers must engage with critical work in disaster studies in order to explore the role that the former has played – and can play – in creating and addressing hazards, vulnerabilities and capacities

Dairy consumption and cardiometabolic diseases: systematic review and updated meta-analyses of prospective cohort studies

Purpose of Review Dairy products contain both beneficial and harmful nutrients in relation to cardiometabolic diseases. Here, we provide the latest scientific evidence regarding the relationship between dairy products and cardiometabolic diseases by reviewing the literature and updating meta-analyses of observational studies. Recent Findings We updated our previous meta-analyses of cohort studies on type 2 diabetes, coronary heart disease (CHD), and stroke with nine studies and confirmed previous results. Total dairy and low-fat dairy (per 200 g/d) were inversely associated with a 3–4% lower risk of diabetes. Yogurt was non-linearly inversely associatedwith diabetes (RR = 0.86, 95%CI: 0.83–0.90 at 80 g/ d). Total dairy and milk were not associated with CHD (RR~1.0). An increment of 200 g of daily milk intake was associated with an 8% lower risk of stroke. Summary The latest scientific evidence confirmed neutral or beneficial associations between dairy products and risk of cardiometabolic diseases