A system dynamics-based scenario analysis of residential solid waste management in Kisumu, Kenya

The problem of solid waste management presents an issue of increasing importance in many low-income settings, including the progressively urbanised context of Kenya. Kisumu County is one such setting with an estimated 500 t of waste generated per day and with less than half of it regularly collected. The open burning and natural decay of solid waste is an important source of greenhouse gas (GHG) emissions and atmospheric pollutants with adverse health consequences. In this paper, we use system dynamics modelling to investigate the expected impact on GHG and PM_2.5 emissions of (i) a waste-to-biogas initiative and (ii) a regulatory ban on the open burning of waste in landfill. We use life tables to estimate the impact on mortality of the reduction in PM_2.5 exposure. Our results indicate that combining these two interventions can generate over 1.1 million tonnes of cumulative savings in GHG emissions by 2035, of which the largest contribution (42%) results from the biogas produced replacing unclean fuels in household cooking. Combining the two interventions is expected to reduce PM_2.5 emissions from the waste and residential sectors by over 30% compared to our baseline scenario by 2035, resulting in at least around 1150 cumulative life years saved over 2021–2035. The contribution and novelty of this study lies in the quantification of a potential waste-to-biogas scenario and its environmental and health impact in Kisumu for the first time.

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We present a system dynamics study of solid waste management in Kisumu, Kenya.

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Scenarios involve a waste-to-biogas initiative and a ban on open burning in landfill.

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Combined scenario generates 1.1m tonnes cumulative GHG savings by 2035.

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Largest contribution (42%) is from biogas substituting traditional cooking fuels.

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Combined scenario may save 1,150 cumulative life years by 2035, plus ~220 more p.a.

Household air pollution in Nairobi's slums: A long-term policy evaluation using participatory system dynamics

58% of Nairobi's population live in informal settlements in extremely poor conditions. Household air pollution is one of the leading causes of premature death and disease in these settlements. Regulatory frameworks and government budgets for household air pollution do not exist and humanitarian organisations remain largely inattentive and inactive on this issue. The purpose of this paper is to evaluate the effectiveness of potential indoor-air related policies, as identified together with various stakeholders, in lowering household air pollution in Nairobi's slums. Applying a novel approach in this context, we used participatory system dynamics within a series of stakeholder workshops in Nairobi, to map and model the complex dynamics surrounding household air pollution and draw up possible policy options. Workshop participants included community members, local and national policy-makers, representatives from parastatals, NGOs and academics. Simulation modelling demonstrates that under business-as-usual, the current trend of slowly improving indoor air quality will soon come to a halt. If we aim to continue to substantially reduce household PM_2.5 levels, a drastic acceleration in the uptake of clean stoves is needed. We identified the potentially high impact of redirecting investment towards household air quality monitoring and health impact assessment studies, therefore raising the public's and the government's awareness and concern about this issue and its health consequences. Such investments, due to their self-reinforcing nature, can entail high returns on investment, but are likely to give 'worse-before-better' results due to the time lags involved. We also discuss the usefulness of the participatory process within similar multi-stakeholder contexts. With important implications for such settings this work advances our understanding of the efficacy of high-level policy options for reducing household air pollution. It makes a case for the usefulness of participatory system dynamics for such complex, multi-stakeholder, environmental issues.

Estimated cost per HIV infection diagnosed through routine HIV testing offered in acute general medical admission units and general practice settings in England

OBJECTIVES

Following national guidelines to expand HIV testing in high-prevalence areas in England, a number of pilot studies were conducted in acute general medical admission units (ACUs) and general practices (GPs) to assess the feasibility and acceptability of testing in these settings. The aim of this study was to estimate the cost per HIV infection diagnosed through routine HIV testing in these settings.

METHODS

Resource use data from four 2009/2010 Department of Health pilot studies (two ACUs; two GPs) were analysed. Data from the pilots were validated and supplemented with information from other sources. We constructed possible scenarios to estimate the cost per test carried out through expanded HIV testing in ACUs and GPs, and the cost per diagnosis.

RESULTS

In the pilots, cost per test ranged from £8.55 to £13.50, and offer time and patient uptake were 2 minutes and 90% in ACUs, and 5 minutes and 60% in GPs, respectively. In scenario analyses we fixed offer time, diagnostic test cost and uptake rate at 2 minutes, £6 and 80% for ACUs, and 5 minutes, £9.60 and 40% for GPs, respectively. The cost per new HIV diagnosis at a positivity of 2/1000 tests conducted was £3230 in ACUs and £7930 in GPs for tests performed by a Band 3 staff member, and £5940 in ACUs and £18 800 in GPs for tests performed by either hospital consultants or GPs.

CONCLUSIONS

Expanded HIV testing may be more cost-efficient in ACUs than in GPs as a consequence of a shorter offer time, higher patient uptake, higher HIV positivity and lower diagnostic test costs. As cost per new HIV diagnosis reduces at higher HIV positivity, expanded HIV testing should be promoted in high HIV prevalence areas.

The response to testosterone undecanoate in men with type 2 diabetes is dependent on achieving threshold serum levels (the BLAST study)

BACKGROUND

The association between testosterone deficiency and insulin resistance in men with type 2 diabetes is well established. Current Endocrine Society and European Association of Urology guidelines recommend the measurement of testosterone levels in all men with type 2 diabetes and in men suffering from erectile dysfunction. It is recognised that a range of physical symptoms appear as the testosterone level falls but few studies have addressed the threshold at which symptoms improve with physiological replacement. We report the first double-blind placebo-controlled study conducted exclusively in a male type 2 diabetes population to assess the metabolic changes with testosterone replacement.

METHODS

The type 2 diabetes registers of seven general practices were screened to establish the prevalence of low testosterone and the associations with diabetes control. Of 550 eligible patients approached, 488 men (mean age 62.6) consented to take part in screening with a morning testosterone level, assessed between 8 and 11 am. This identified 211 patients for a double-blind placebo-controlled study of long acting testosterone undecanoate (TU) 1000 mg lasting 30 weeks followed by 52 weeks of open label use. The population was divided into a SEVERE group with either total testosterone (TT) of 8 nmol/l or less or free testosterone (FT) 180 pmol/l or less or a MILD group with TT 8.1-12 nmol/l or FT 181-250 pmol/l.

RESULTS

Men in the SEVERE group increased mean through TT from 7.73 nmol/l at baseline to 9.93 at 30 weeks and the MILD group from 10.47 to 11.94. The SEVERE group showed marked improvement in sexual function, but no significant improvement in metabolic parameters. The MILD group showed no improvement in sexual function, but significant improvement in weight, body mass index, waist circumference and Hospital Anxiety and Depression Scale. Improvement was seen in all parameters during 52 weeks open label treatment where trough TT levels approached 15 nmol/l. Baseline prostate-specific antigen (PSA) was lower in the SEVERE group and increased with TU for 30 weeks and then stabilised. There was no increase in PSA with treatment in the MILD group.

CONCLUSIONS

Testosterone undecanoate significantly improves sexual parameters and Ageing Male Symptom Score, but not metabolic factors at 30 weeks in men with SEVERE testosterone deficiency syndrome (TDS). In men with MILD TDS, significant improvements in metabolic but not sexual parameters were seen, suggesting that there are threshold levels for response to testosterone replacement therapy and that trials of therapy need to achieve sustained therapeutic levels to be effective. PSA showed minor rises, but only for 30 weeks in the SEVERE group.

Cytochrome P450-encoding genes from the Heliconius genome as candidates for cyanogenesis

Cytochrome P450s are important both in the metabolism of xenobiotics and the production of compounds such as cyanogenic glucosides, which insects use in their defence. In the present study, we use transcriptomic and genomic information to isolate and name P450-encoding genes from the butterfly Heliconius melpomene. We classify each of the putative genes into its appropriate superfamily and compare the distribution of P450s across sequenced insects. We also identify homologues of two P450s known to be involved in cyanogenesis in the six-spot Burnet moth, Zygaena filipendulae. Classification of Heliconius P450s should be an important step in the dissection of their role in the exploitation of their host plant, the passion vine Passiflora.

Ambient temperature and activation of implantable cardioverter defibrillators

The degree to which weather influences the occurrence of serious cardiac arrhythmias is not fully understood. To investigate, we studied the timing of activation of implanted cardiac defibrillators (ICDs) in relation to daily outdoor temperatures using a fixed stratum case-crossover approach. All patients attending ICD clinics in London between 1995 and 2003 were recruited onto the study. Temperature exposure for each ICD patient was determined by linking each patient's postcode of residence to their nearest temperature monitoring station in London and the South of England. There were 5,038 activations during the study period. Graphical inspection of ICD activation against temperature suggested increased risk at lower but not higher temperatures. For every 1 °C decrease in ambient temperature, risk of ventricular arrhythmias up to 7 days later increased by 1.2 % (95 % CI -0.6 %, 2.9 %). In threshold models, risk of ventricular arrhythmias increased by 11.2 % (0.5 %, 23.1 %) for every 1° decrease in temperature below 2 °C. Patients over the age of 65 exhibited the highest risk. This large study suggests an inverse relationship between ambient outdoor temperature and risk of ventricular arrhythmias. The highest risk was found for patients over the age of 65. This provides evidence about a mechanism for some cases of low-temperature cardiac death, and suggests a possible strategy for reducing risk among selected cardiac patients by encouraging behaviour modification to minimise cold exposure.

Involvement in research activities and factors influencing research capacity among dietitians

BACKGROUND

A healthcare professional's aptitude to develop research skills and actively engage in research is necessary to optimise healthcare efficacy. The present study investigated the factors that contribute to research capacity within the Australian dietetic workforce.

METHODS

Queensland-based dietitians scored their department and individual skill or success in research on a 10-point scale using an anonymous online survey that incorporated the validated Research Capacity in Context tool. Descriptive statistics were assessed against geographical setting, dietetic experience and the proportion of role (Full Time Equivalent; FTE) designated to research. Research activities were defined by the number of items currently involved in or completed in the past 6 months (n = 11). Factors associated with research activities were assessed by multivariable linear regression.

RESULTS

Dietitians (n = 130) identified having a moderate skill or success in 14 research items [mean (SD) 5.1 (1.7)] and perceived that their departments provided a moderate level of research support in 19 research items [mean (SD) 6.1 (2.5)]. Geographical setting, the proportion of role designated to research (FTE) and participation in research activities were associated with individual and department ratings of research skill or success. Research involvement was predicted by the proportion of role (FTE) designated to research (β = 0.34, t = 4.16, P < 0.001) and years of experience in dietetics (β = 0.32, t = 2.67, P < 0.009).

CONCLUSIONS

A dietitian's capacity for research is related to professional experience and the designation of research in the role description. The findings of the present study will provide a baseline of research capacity and expertise among dietitians, and also inform the strategic development of building research capacity.

Association of mortality with high temperatures in a temperate climate: England and Wales

BACKGROUND

It is well known that high ambient temperatures are associated with increased mortality, even in temperate climates, but some important details are unclear. In particular, how heat-mortality associations (for example, slopes and thresholds) vary by climate has previously been considered only qualitatively.

METHODS

An ecological time-series regression analysis of daily counts of all-cause mortality and ambient temperature in summers between 1993 and 2006 in the 10 government regions was carried out, focusing on all-cause mortality and 2-day mean temperature (lags 0 and 1).

RESULTS

All regions showed evidence of increased risk on the hottest days, but the specifics, in particular the threshold temperature at which adverse effects started, varied. Thresholds were at about the same centile temperatures (the 93rd, year-round) in all regions-hotter climates had higher threshold temperatures. Mean supra-threshold slope was 2.1%/°C (95% CI 1.6 to 2.6), but regions with higher summer temperatures showed greater slopes, a pattern well characterised by a linear model with mean summer temperature. These climate-based linear-threshold models capture most, but not all, the association; there was evidence for some non-linearity above thresholds, with slope increasing at highest temperatures.

CONCLUSION

Effects of high daily summer temperatures on mortality in English regions are quite well approximated by threshold-linear models that can be predicted from the region's climate (93rd centile and mean summer temperature). It remains to be seen whether similar relationships fit other countries and climates or change over time, such as with climate change.

Pyrosequencing the Manduca sexta larval midgut transcriptome: messages for digestion, detoxification and defence

The tobacco hornworm Manduca sexta is an important model for insect physiology but genomic and transcriptomic data are currently lacking. Following a recent pyrosequencing study generating immune related expressed sequence tags (ESTs), here we use this new technology to define the M. sexta larval midgut transcriptome. We generated over 387,000 midgut ESTs, using a combination of Sanger and 454 sequencing, and classified predicted proteins into those involved in digestion, detoxification and immunity. In many cases the depth of 454 pyrosequencing coverage allowed us to define the entire cDNA sequence of a particular gene. Many new M. sexta genes are described including up to 36 new cytochrome P450s, some of which have been implicated in the metabolism of host plant-derived nicotine. New lepidopteran gene families such as the beta-fructofuranosidases, previously thought to be restricted to Bombyx mori, are also described. An unexpectedly high number of ESTs were involved in immunity, for example 39 contigs encoding serpins, and the increasingly appreciated role of the midgut in insect immunity is discussed. Similar studies of other tissues will allow for a tissue by tissue description of the M. sexta transcriptome and will form an essential complimentary step on the road to genome sequencing and annotation.

Effects of ambient temperature on the incidence of myocardial infarction

CONTEXT

While the effects of weather and, in particular, ambient temperature on overall mortality are well documented, the strength of the evidence base for the effects on acute myocardial infarction (MI) are less clear.

OBJECTIVE

To systematically review studies specifically focusing on the effects of temperature on MI.

DATA SOURCES

Medline, Embase, and GeoBase publication databases, as well as reference lists, and the websites of a number of relevant public organisations.

STUDY SELECTION

Studies of original data in which ambient temperature was an exposure of interest and MI a specific outcome were selected.

DATA EXTRACTION

The reported effects of ambient temperature on the risk of MI, including effect sizes and confidence intervals, where possible, were recorded. Methodological details were also extracted, including study population, location and setting, ascertainment of MI events, adjustment for potential confounders and consideration of lagged effects.

RESULTS

19 studies were identified, of which 14 considered the short-term effects of temperature on a daily timescale, the remainder looking at longer-term effects. Overall, 8 of the 12 studies which included relevant data from the winter season reported a statistically significant short-term increased risk of MI at lower temperatures, while increases in risk at higher temperatures were reported in 7 of the 13 studies with relevant data. A number of differences were identified between studies in the population included demographics, location, local climate, study design and statistical methodology.

CONCLUSION

A number of studies, including some that were large and relatively well controlled, suggested that both hot and cold weather had detrimental effects on the short-term risk of MI. However, further research with consistent methodology is needed to clarify the magnitude of these effects and to show which populations and individuals are vulnerable.

Effects of air pollution on the incidence of myocardial infarction

CONTEXT

Short-term fluctuations in air pollution have been associated with changes in both overall and cardiovascular mortality.

OBJECTIVE

To consider the effects of air pollution on myocardial infarction (MI) risk by systematically reviewing studies looking at this specific outcome.

DATA SOURCES

Medline, Embase and TOXNET publication databases, as well as reference lists and the websites of relevant public organisations.

STUDY SELECTION

Studies presenting original data with MI as a specific outcome and one or more of the following as an exposure of interest were included: particulate matter (PM), black carbon/black smoke, ozone, carbon monoxide, nitrogen oxides, sulphur dioxide and traffic exposure.

DATA EXTRACTION

The effects of each pollutant on risk of MI, including effect sizes and confidence intervals, were recorded where possible. Methodological details were also extracted including study population, location and setting, ascertainment of MI events, adjustment for potential confounders and consideration of lagged effects.

RESULTS

26 studies were identified: 19 looked at the short-term effects of pollution on a daily timescale; the remaining 7 at longer-term effects. A proportion of studies reported statistically significant detrimental effects of PM with diameter <2.5 microm (3/5 studies, risk increase estimates ranging from 5 to 17% per 10 microg/m(3) increase), PM <10 microm (3/10, 0.7-11% per 10 microg/m(3)), CO (6/14, 2-4% per ppm), SO(2) (6/13, effect estimates on varied scales) and NO(2 )(6/13, 1-9% per 10 ppb). Increasing ozone levels were associated with a reduction in MI risk in 3/12 studies. A number of differences in location, population and demographics and study methodology between studies were identified that might have affected results.

CONCLUSION

There is some evidence that short-term fluctuations in air pollution affect the risk of MI. However, further studies are needed to clarify the nature of these effects and identify vulnerable populations and individuals.

Multidisciplinary research in public health: a case study of research on access to green space

OBJECTIVES

Quantitative analysis of the physical and demographic parameters of access to Thames Chase Community Forest (TCCF), and how these have changed between 1990 and 2003; and qualitative exploration of our understanding of the links between health and the natural environment (TCCF), with a focus on the issue of 'access' to green space.

STUDY DESIGN

Multimethod design involving both quantitative (analysis of physical access to green space) and qualitative (ethnography) components.

METHODS

Quantitative analysis, using geographical information systems, of physical access to the community forest; and ethnographic research including participant observation, non-participant observation, in-depth interviews and attendance at meetings and conferences.

RESULTS

The quantitative analysis showed that public access to green space improved between 1990 and 2003 as a result of the regeneration and acquisition of new areas, and the average reduction in distance to green space was 162 m. However, such improvements were distributed differentially between population groups. In both 1990 and 2003, people from deprived areas and in poorer health had better access to green space than people from less deprived areas, but the greatest improvement in access to green space over this interval occurred in areas of below average deprivation (i.e. in the more affluent areas). The ethnographic research showed different interpretations of the notion of access. Use of TCCF was determined by a variety of factors including whether a person could 'imagine themselves' using such a space, different perceptions of what is actually being accessed (e.g. a place to exercise or a place to socialise), and ideas about using the countryside 'properly'.

CONCLUSIONS

The health benefits of using a green space, such as TCCF, for walking or exercising are well recognized. However, whether people choose to use local green space may be determined by a variety of factors. These are likely to include physical distance to access of green space, as well as perceptions and understandings of what is being accessed and how it should be used. This study has also illustrated the ways in which multiple methods can be integrated in public health research, and the merits of different approaches to undertaking multidisciplinary work of this type.

A randomised controlled trial of cognitive behaviour therapy in adolescents with major depression treated by selective serotonin reuptake inhibitors. The ADAPT trial

OBJECTIVES

To determine if, in the short term, depressed adolescents attending routine NHS Child and Adolescent Mental Health Services (CAMHS), and receiving ongoing active clinical care, treatment with selective serotonin reuptake inhibitors (SSRIs) plus cognitive behaviour therapy (CBT) compared with SSRI alone, results in better healthcare outcomes.

DESIGN

A pragmatic randomised controlled trial (RCT) was conducted on depressed adolescents attending CAMHS who had not responded to a psychosocial brief initial intervention (BII) prior to randomisation.

SETTING

Six English CAMHS participated in the study.

PARTICIPANTS

A total of 208 patients aged between 11 and 17 years were recruited and randomised.

INTERVENTIONS

All participants received active routine clinical care in a CAMHS outpatient setting and an SSRI and half were offered CBT.

MAIN OUTCOME MEASURES

The duration of the trial was a 12-week treatment phase, followed by a 16-week maintenance phase. Follow-up assessments were at 6, 12 and 28 weeks. The primary outcome measure was the Health of the Nation Outcome Scales for Children and Adolescents (HoNOSCA). Secondary outcome measures were self-report depressive symptoms, interviewer-rated depressive signs and symptoms, interviewer-rated psychosocial impairment and clinical global impression of response to treatment. Information on resource use was collected in interview at baseline and at the 12- and 28-week follow-up assessments using the Child and Adolescent Service Use Schedule (CA-SUS).

RESULTS

Of the 208 patients randomised, 200 (96%) completed the trial to the primary end-point at 12 weeks. By the 28-week follow-up, 174 (84%) participants were re-evaluated. Overall, 193 (93%) participants had been assessed at one or more time points. Clinical characteristics indicated that the trial was conducted on a severely depressed group. There was significant recovery at all time points in both arms. The findings demonstrated no difference in treatment effectiveness for SSRI + CBT over SSRI only for the primary or secondary outcome measures at any time point. This lack of difference held when baseline and treatment characteristics where taken into account (age, sex, severity, co-morbid characteristics, quality and quantity of CBT treatment, number of clinic attendances). The SSRI + CBT group was somewhat more expensive over the 28 weeks than the SSRI-only group (p=0.057) and no more cost-effective. Over the trial period there was on average a decrease in suicidal thoughts and self-harm compared with levels recorded at baseline. There was no significant increase in disinhibition, irritability and violence compared with levels at baseline. Around 20% (n=40) of patients in the trial were non-responders. Of these, 17 (43%) showed no improvement by 28 weeks and 23 (57%) were considered minimally (n=10) or moderately to severely worse (n=13).

CONCLUSIONS

For moderately to severely depressed adolescents who are non-responsive to a BII, the addition of CBT to fluoxetine plus routine clinical care does not improve outcome or confer protective effects against adverse events and is not cost-effective. SSRIs (mostly fluoxetine) are not likely to result in harmful adverse effects. The findings are broadly consistent with existing guidelines on the treatment of moderate to severe depression. Modification is advised for those presenting with moderate (6-8 symptoms) to severe depressions (>8 symptoms) and in those with either overt suicidal risk and/or high levels of personal impairment. In such cases, the time allowed for response to psychosocial interventions should be no more than 2-4 weeks, after which fluoxetine should be prescribed. Further research should focus on evaluating the efficacy of specific psychological treatments against brief psychological intervention, determining the characteristics of patients with severe depression who are non-responsive to fluoxetine, relapse prevention in severe depression and improving tools for determining treatment responders and non-responders.

Back pain in osteoporotic vertebral fractures

This review article examines the epidemiology and pathogenesis of back pain and vertebral fractures in osteoporosis, reviewing the management of pain in patients with vertebral fractures and the direct and indirect effect of osteoporosis treatments on back pain.

INTRODUCTION

The management of patients with vertebral fractures has largely concentrated on the prevention of further fractures by the treatment of underlying osteoporosis, with drug treatment for acute and chronic back pain and the non-pharmacological management of vertebral fractures receiving less attention.

DISCUSSION

Emerging evidence suggests that, in addition to reducing the incidence of vertebral fractures, calcitonin, intravenous bisphosphonates and teriparatide may also have a direct effect on bone pain. Targeted analgesia, tailored to individual need is often required in both the acute and chronic phases following vertebral fracture. Vertebroplasty and kyphoplasty have also been approved for use in the management of vertebral fractures and may prove useful in selected patients unresponsive to conventional pain relief. There is some evidence to support the use of individualised tailored exercise programmes aimed at strengthening back muscles to maintain bone density and reduce further fracture incidence. In addition the use of specific orthoses may help to reduce kyphosis, improve mobility and reduce pain.

CONCLUSION

Chronic back pain associated with vertebral fracture provides a great challenge to health care professionals and the patient. This demands a combination of options, including not only therapeutic interventions, but also physiotherapy, psychological support and patient education.

Clinical trial: oral prednisolone metasulfobenzoate (Predocol) vs. oral prednisolone for active ulcerative colitis

BACKGROUND

Systemic corticosteroids are effective in ulcerative colitis but commonly cause side effects.

AIM

To compare the safety and efficacy of a sparingly absorbed formulation of prednisolone metasulfobenzoate (Predocol) with a conventional tapering course of oral prednisolone.

METHOD

In a double-blind randomized study, 59 active ulcerative colitis patients received Predocol 40 mg/day for 6 months, 61 received Predocol 60 mg/day for 6 months and 61 received prednisolone 40 mg/day for 2 weeks, tapered to week 8, followed by placebo until 6 months.

RESULTS

Steroid-related side effects assessed using a 10-cm visual analogue scale were fewer at 2 months with Predocol 40 mg [VAS 8.1 cm (2.6), mean (s.d.)], or 60 mg [8.1 (2.1)] compared with prednisolone [6.7 (2.7); P = 0.01]. Mood changes affected 43% receiving prednisolone at 4 weeks vs. 8% for Predocol 40 mg (P = 0.001). Remission rates (Powell-Tuck < or =2) at 2 months were Predocol 40 mg 46%, Predocol 60 mg 28% and tapering prednisolone 41% (P = 0.13). Visual analogue scale for efficacy also showed non-inferiority for Predocol 40 mg/day. Remission rates at 6 months were Predocol 40 mg 51%, Predocol 60 mg 38% and tapering prednisolone 32% (P = 0.08).

CONCLUSION

Predocol 40 mg/day has similar efficacy but markedly fewer side effects than a conventional tapering prednisolone regimen (ISRCTN14133410).

Cost-effectiveness of selective serotonin reuptake inhibitors and routine specialist care with and without cognitive behavioural therapy in adolescents with major depression

BACKGROUND

Major depression is an important and costly problem among adolescents, yet evidence to support the provision of cost-effective treatments is lacking.

AIMS

To assess the short-term cost-effectiveness of combined selective serotonin reuptake inhibitors (SSRIs) and cognitive-behavioural therapy (CBT) together with clinical care compared with SSRIs and clinical care alone in adolescents with major depression.

METHOD

Pragmatic randomised controlled trial in the UK. Outcomes and costs were assessed at baseline, 12 and 28 weeks.

RESULTS

The trial comprised 208 adolescents, aged 11-17 years, with major or probable major depression who had not responded to a brief initial psychosocial intervention. There were no significant differences in outcome between the groups with and without CBT. Costs were higher in the group with CBT, although not significantly so (P=0.057). Cost-effectiveness analysis and exploration of the associated uncertainty suggest there is less than a 30% probability that CBT plus SSRIs is more cost-effective than SSRIs alone.

CONCLUSIONS

A combination of CBT plus SSRIs is not more cost-effective in the short-term than SSRIs alone for treating adolescents with major depression in receipt of routine specialist clinical care.

House-level risk factors for triatomine infestation in Colombia

BACKGROUND

Chagas disease, transmitted domestically by triatomine bugs, is the most important vector-borne disease in Latin America. The association between triatomine infestation and housing characteristics was investigated based on a standardized survey in 41 971 houses in 15 Departments in Colombia.

METHODS

Multivariate logistic regression was used to test for associations of two highly correlated infestation measures of infestation (householders reporting having seen triatomines inside the house, and sending triatomines to the survey team), with 15 household-level risk factors. Risks were measured relative to a reference category of houses with up to three inhabitants, area up to 50 m(2), unplastered adobe walls, thatch roof and no outbuildings or domestic animals.

RESULTS

The probability of seeing triatomines was highest for households with over seven inhabitants (OR = 1.24, 95% CI 1.11-1.39), overhead storage space (OR = 1.16, 95% CI 1.03-1.32), grain shed (OR = 1.25, 95% CI 1.02-1.52), cats (OR = 1.27, 95% CI 1.14-1.42) and pigs (OR = 1.16, 95% CI 1.03-1.30). Lowest risks were in houses with wooden walls (OR = 0.46, 95% CI 0.34-0.61), fully plastered walls (OR = 0.78, 95% CI 0.68-0.88), roofs made of tiles (OR = 0.51, 95% CI 0.33-0.78) and flagstone floors (OR = 0.57, 95% CI 0.42-0.76). Results for householders returning triatomines support this set of risk factors, but with wider confidence intervals.

CONCLUSIONS

Surveillance of a few easily assessed household characteristics provides an accurate, rapid assessment of house-level variation in risk. Measured effect sizes for specific structural characteristics could be used to maximize the cost-effectiveness of programmes to reduce vector infestation and interrupt Chagas disease transmission by improving house quality.

Vertical inertial sliding drive for coarse and fine approaches in scanning probe microscopy

Mechanisms for controlled approach of a probe tip toward the sample surface are essential in high resolution imaging by scanning probe microscopy (SPM). This work describes the development and performance of an inertial sliding drive capable of translating a relatively large mass (25 g) at up to 1 mms over 1 cm with step sizes of 10-250 nm in ambient conditions using various wave forms as measured by fiber optic interferometry. The drive functions independent of orientation with a threshold voltage of less than 15 V using a single drive signal. Use of piezotube actuators in a radially symmetric arrangement provides guided motion and minimizes differential thermal expansion between critical components. Controlled translation of the entire scanning component in both ambient and electrochemical scanning tunneling microscopy has been routinely achieved with no evidence of tip crash. This device has been specifically designed for use in in situ SPM applications where stability of the sample and that of the liquid environment are paramount.

Modern and historical fluxes of halogenated organic contaminants to a lake in the Canadian arctic, as determined from annually laminated sediment cores

Two annually laminated cores collected from Lake DV09 on Devon Island in May 1999 were dated using 210Pb and 137Cs, and analyzed for a variety of halogenated organic contaminants (HOCs), including polychlorinated biphenyls (PCBs), organochlorine pesticides, short-chain polychlorinated n-alkanes (sPCAs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polybrominated diphenyl ethers (PBDEs). Dry weight HOC concentrations in Lake DV09 sediments were generally similar to other remote Arctic lakes. Maximum HOC fluxes often agreed well with production maxima, although many compound groups exhibited maxima at or near the sediment surface, much later than peak production. The lower than expected HOC concentrations in older sediment slices may be due to anaerobic degradation and possibly to dilution resulting from a temporary increase in sedimentation rate observed between the mid-1960s and 1970s. Indeed, temporal trends were more readily apparent for those compound classes when anaerobic metabolites were also analyzed, such as for DDT and toxaphene. However, it is postulated here for the first time that the maximum or increasing HOC surface fluxes observed for many of the major compound classes in DV09 sediments may be influenced by climate variation and the resulting increase in algal primary productivity which could drive an increasing rate of HOC scavenging from the water column. Both the fraction (F(TC)) and enantiomer fraction (EF) of trans-chlordane (TC) decreased significantly between 1957 and 1997, suggesting that recent inputs to the lake are from weathered chlordane sources. PCDD/Fs showed a change in sources from pentachlorophenol (PeCP) in the 1950s and 1960s to combustion sources into the 1990s. Improvements in combustion technology may be responsible for the reducing the proportion of TCDF relative to OCDD in the most recent slice.

Area deprivation, social class, and quality of life among people aged 75 years and over in Britain

BACKGROUND

There is a shortage of research studies that assess how selected characteristics of neighbourhood and personal social circumstances contribute towards health-related quality of life (QoL) among older people.

METHODS

Analysis of baseline data for 5581 people aged > or =75 years and over from the Trial of Assessment and Management of Older People in the Community. The scores for four dimensions from the UK version of the Sickness Impact Profile and for the Philadelphia Geriatric Morale Scale were analysed in relation to individual social class and the Carstairs score of socioeconomic deprivation for the enumeration district of residence.

RESULTS

In age and sex adjusted analyses, the proportion of participants of social class IV/V living in the most deprived areas who were in the quintile with worst QoL scores was more than double that among those from social class I/II living in the least deprived areas. Individual social class and area deprivation score contributed roughly equally to this doubling for home management, self-care and social interaction, whereas social class appeared a stronger determinant for mobility. Adjustment for living circumstances, health symptoms, and health behaviours substantially reduced the excess risk associated with social class and area deprivation. Being in a rural area was associated with lower risk of poor morale.

CONCLUSION

Poor socioeconomic characteristics of both the area and the individual are associated with worse functioning (QoL) of older people in the community. This is not fully explained by health status. Policy should consider community-level interventions as well as those directed at individuals.

Contrasting patterns of mortality and hospital admissions during hot weather and heat waves in Greater London, UK

BACKGROUND

Epidemiological research has shown that mortality increases during hot weather and heat waves, but little is known about the effect on non-fatal outcomes in the UK.

AIMS AND METHODS

The effects of hot weather and heat waves on emergency hospital admissions were investigated in Greater London, UK, for a range of causes and age groups. Time series analyses were conducted of daily emergency hospital admissions, 1 April 1994 to 31 March 2000, using autoregressive Poisson models with adjustment for long term trend, season, day of week, public holidays, the Christmas period, influenza, relative humidity, air pollution (ozone, PM10), and overdispersion. The effects of heat were modelled using the average of the daily mean temperature over the index and previous two days.

RESULTS

There was no clear evidence of a relation between total emergency hospital admissions and high ambient temperatures, although there was evidence for heat related increases in emergency admissions for respiratory and renal disease, in children under 5, and for respiratory disease in the 75+ age group. During the heat wave of 29 July to 3 August 1995, hospital admissions showed a small non-significant increase: 2.6% (95% CI -2.2 to 7.6), while daily mortality rose by 10.8% (95% CI 2.8 to 19.3) after adjusting for time varying confounders.

CONCLUSIONS

The impact of hot weather on mortality is not paralleled by similar magnitude increases in hospital admissions in the UK, which supports the hypothesis that many heat related deaths occur in people before they come to medical attention. This has evident implications for public health, and merits further enquiry.

Methodological issues in using drugs data in epidemiology

Using drugs data in epidemiological studies is becoming fashionable with the large databases available today. We describe the philosophical basis and the main methodological issues. The process leading a patient affected by a disease to be treated with an appropriate drug appears to be complex, and influenced by external and internal many factors, described here. The disease-drug use relationship is disentangled describing its main characteristics. Drug use data means the information concerning the use of drugs, which encompasses any form of record, on paper or computerised, collected from patients, doctors prescribing the drug, pharmacists dispensing it, the drug company that produces it, or its distributor. The possible sources of drug use data are described, along with the possible strengths and weaknesses of each source. Various examples of uses of drug utilisation data as indicator in epidemiological researches are presented. Drug utilisation studies are a recent issue of public health research, merging knowledge of public health doctors, epidemiologists, pharmacologists and health economists. Automated databases demonstrate nowadays to be a valuable approach to drug utilisation investigation. In conclusion, the aim of any forward looking health care system should be to collect and freely circulate these detailed information, allowing not only useful health care planning but also indeep, population based, health research.

The role of drug use data in public health research

The growing importance of drug consumption automated databases in public health research is summarised in this research. Dispensed drugs data, and drug consumption data more in general, are a relatively new source of information for health research. This analysis takes into consideration the known uses of drug consumption data in various fields of health related research. Pharmacoepidemiology examples of adverse drug reaction studies are presented along with drug prescription surveillance and analysis of prescribing patterns, useful tools for health services evaluation as well as health economics, from the simple evaluation of health care burden for drug expenditure to the various studies of cost of drugs. Other fields of use are prevalence and incidence epidemiology studies, or causal inference studies using drugs data as health indicators. Drug utilisation automated databases, organised and maintained in large areas, with individual information, seem to improve the feasibility and usefulness of this kind of studies. It reduces the need for time, money and people to perform valid scientific investigations, in epidemiology as well as in other areas of health research.