Exploring young people's perspectives of inequalities in health: a qualitative study

Background

Reducing inequalities in health is an enduring global public health challenge. Worryingly in England, inequalities across some groups and places are worsening, highlighted and exacerbated by the Covid-19 pandemic. While there has been growing interest in exploring public understandings of health inequalities, few studies have explored the views of young people. Our study seeks to redress this by exploring young people's perspectives of inequalities in health.

Methods

Working with existing youth organisations, we recruited young people (aged 13-21) from six youth groups in areas of high deprivation across three geographical locations in England. Each group took part in three interlinked focus groups (n = 18), the majority of which were run online using video conferencing platforms. Focus groups were co-delivered with partnering youth organisations during 2021. They involved participatory concept mapping activities, and the discussion of health related news articles.

Results

Key themes emerged around young people's perspectives of: i) factors influencing health within their local area; ii) understandings of inequalities in health; and iii) key messages to convey to those with a role in addressing health inequalities at a place level.

Conclusions

Our study highlights the importance of exploring and understanding young people's perspectives of inequalities in order to better shape policies which are supported by the communities and people they impact.

Key messages

Young people have a nuanced, experiential understanding of key factors influencing their health and inequalities in health within their local areas. Building upon young people’s understandings of inequalities in health provides opportunities to mobilise support for policies seeking to change the distribution of key social determinants.

Getting shops to voluntarily stop selling cheap, strong beers and ciders: a time-series analysis evaluating impacts on alcohol availability and purchasing

BACKGROUND

'Reducing the Strength' (RtS) is a public health initiative encouraging retailers to voluntarily stop selling cheap, strong beers/ciders (≥6.5% alcohol by volume). This study evaluates the impact of RtS initiatives on alcohol availability and purchasing in three English counties with a combined population of 3.62 million people.

METHODS

We used a multiple baseline time-series design to examine retail data over 29 months from a supermarket chain that experienced a two-wave, area-based role out of RtS: initially 54 stores (W1), then another 77 stores (W2). We measured impacts on units of alcohol sold (primary outcome: beers/ciders; secondary outcome: all alcoholic products), economic impacts on alcohol sales and substitution effects.

RESULTS

We observed a non-significant W1 increase (+3.7%, 95% CI: -11.2, 21.0) and W2 decrease (-6.8%, 95% CI: -20.5, 9.4) in the primary outcome. We observed a significant W2 decrease in units sold across all alcohol products (-10.5%, 95% CI: -19.2, -0.9). The direction of effect between waves was inconsistent for all outcomes, including alcohol sales, with no evidence of substitution effects.

CONCLUSIONS

In the UK, voluntary RtS initiatives appear to have little or no impact on reducing alcohol availability and purchase from the broader population of supermarket customers.

Factors influencing fruit and vegetable intake among urban Fijians: A qualitative study

Low fruit and vegetable intake is an important risk factor for micronutrient deficiencies and non-communicable diseases, but many people worldwide, including most Fijians, eat less than the World Health Organization recommended amount. The present qualitative study explores factors that influence fruit and vegetable intake among 57 urban Fijians (50 women, 7 men) of indigenous Fijian (iTaukei) and South Asian (Indian) descent. Eight focus group discussions were held in and around Suva, Fiji's capital and largest urban area, which explored motivation for eating fruit and vegetables, understandings of links to health and disease, availability and sources, determinants of product choice, and preferred ways of preparing and eating fruit and vegetables. Data were analysed using thematic content analysis. Regardless of ethnicity, participants indicated that they enjoyed and valued eating fruit and vegetables, were aware of the health benefits, and had confidence in their cooking skills. In both cultures, fruit and vegetables were essential components of traditional diets. However, increasing preferences for processed and imported foods, and inconsistent availability and affordability of high-quality, low-priced, fresh produce, were identified as important barriers. The findings indicate that efforts to improve fruit and vegetable intake in urban Fijians should target the stability of the domestic fruit and vegetable supply and access.

Responsibility without legal authority? Tackling alcohol-related health harms through licensing and planning policy in local government

Background

The power to influence many social determinants of health lies within local government sectors that are outside public health's traditional remit. We analyse the challenges of achieving health gains through local government alcohol control policies, where legal and professional practice frameworks appear to conflict with public health action.

Methods

Current legislation governing local alcohol control in England and Wales is reviewed and analysed for barriers and opportunities to implement effective population-level health interventions. Case studies of local government alcohol control practices are described.

Results

Addressing alcohol-related health harms is constrained by the absence of a specific legal health licensing objective and differences between public health and legal assessments of the relevance of health evidence to a specific place. Local governments can, however, implement health-relevant policies by developing local evidence for alcohol-related health harms; addressing cumulative impact in licensing policy statements and through other non-legislative approaches such as health and non-health sector partnerships. Innovative local initiatives—for example, minimum unit pricing licensing conditions—can serve as test cases for wider national implementation.

Conclusions

By combining the powers available to the many local government sectors involved in alcohol control, alcohol-related health and social harms can be tackled through existing local mechanisms.

Adaptive e-learning to improve dietary behaviour: a systematic review and cost-effectiveness analysis

BACKGROUND

UK public health policy strongly advocates dietary change for the improvement of population health and emphasises the importance of individual empowerment to improve health. A new and evolving area in the promotion of dietary behavioural change is 'e-learning', the use of interactive electronic media to facilitate teaching and learning on a range of issues including health. The high level of accessibility, combined with emerging advances in computer processing power, data transmission and data storage, makes interactive e-learning a potentially powerful and cost-effective medium for improving dietary behaviour.

OBJECTIVE

This review aims to assess the effectiveness and cost-effectiveness of adaptive e-learning interventions for dietary behaviour change, and also to explore potential psychological mechanisms of action and components of effective interventions.

DATA SOURCES

Electronic bibliographic databases (Cumulative Index to Nursing and Allied Health Literature, The Cochrane Library, Dissertation Abstracts, EMBASE, Education Resources Information Center, Global Health, Health Economic Evaluations Database, Health Management Information Consortium, MEDLINE, PsycINFO and Web of Science) were searched for the period January 1990 to November 2009. Reference lists of included studies and previous reviews were also screened; authors were contacted and trial registers were searched.

REVIEW METHODS

Studies were included if they were randomised controlled trials, involving participants aged ≥ 13 years, which evaluated the effectiveness of interactive software programs for improving dietary behaviour. Primary outcomes were measures of dietary behaviours, including estimated intakes or changes in intake of energy, nutrients, dietary fibre, foods or food groups. Secondary outcome measures were clinical outcomes such as anthropometry or blood biochemistry. Psychological mediators of dietary behaviour change were also investigated. Two review authors independently screened results and extracted data from included studies, with any discrepancies settled by a third author. Where studies reported the same outcome, the results were pooled using a random-effects model, with weighted mean differences (WMDs), and 95% confidence intervals (CIs) were calculated. Cost-effectiveness was assessed in two ways: through a systematic literature review and by building a de novo decision model to assess the cost-effectiveness of a 'generic' e-learning device compared with dietary advice delivered by a health-care professional.

RESULTS

A total of 36,379 titles were initially identified by the electronic searches, of which 43 studies were eligible for inclusion in the review. All e-learning interventions were delivered in high-income countries. The most commonly used behavioural change techniques reported to have been used were goal setting; feedback on performance; information on consequences of behaviour in general; barrier identification/problem solving; prompting self-monitoring of behaviour; and instruction on how to perform the behaviour. There was substantial heterogeneity in the estimates of effect. E-learning interventions were associated with a WMD of +0.24 (95% CI 0.04 to 0.44) servings of fruit and vegetables per day; -0.78 g (95% CI -2.5 g to 0.95 g) total fat consumed per day; -0.24 g (95% CI -1.44 g to 0.96 g) saturated fat intake per day; -1.4% (95% CI -2.5% to -0.3%) of total energy consumed from fat per day; +1.45 g (95% CI -0.02 g to 2.92 g) dietary fibre per day; +4 kcal (95% CI -85 kcal to 93 kcal) daily energy intake; -0.1 kg/m2 (95% CI -0.7 kg/m2 to 0.4 kg/m2) change in body mass index. The base-case results from the E-Learning Economic Evaluation Model suggested that the incremental cost-effectiveness ratio was approximately £102,112 per quality-adjusted life-year (QALY). Expected value of perfect information (EVPI) analysis showed that although the individual-level EVPI was arguably negligible, the population-level value was between £37M and £170M at a willingness to pay of £20,000-30,000 per additional QALY.

LIMITATIONS

The limitations of this review include potential reporting bias, incomplete retrieval of completed research studies and data extraction errors.

CONCLUSION

The current clinical and economic evidence base suggests that e-learning devices designed to promote dietary behaviour change will not produce clinically significant changes in dietary behaviour and are at least as expensive as other individual behaviour change interventions.

FUTURE WORK RECOMMENDATIONS

Despite the relatively high EVPI results from the cost-effectiveness modelling, further clinical trials of individual e-learning interventions should not be undertaken until theoretically informed work that addresses the question of which characteristics of the target population, target behaviour, content and delivery of the intervention are likely to lead to positive results, is completed.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Improving the transition between paediatric and adult healthcare: a systematic review

INTRODUCTION

The transition between paediatric and adult care for young people with chronic illness or disability is often poorly managed, with adverse consequences for health. Although many agree that adolescent services need to be improved, there is little empirical data on which policies can be based.

OBJECTIVES

To systematically review the evidence of effectiveness of transitional care programmes in young people aged 11-25 with chronic illness (physical or mental) or disability, and identify their successful components.

DESIGN

A systematic literature review in July 2010 of studies which consistently evaluated health outcomes following transition programmes, either by comparison with a control group or by measurement pre-intervention and post-intervention.

RESULTS

10 studies met the inclusion criteria, six of which showed statistically significant improvements in outcomes. Descriptive analysis identified three broad categories of intervention, directed at: the patient (educational programmes, skills training); staffing (named transition co-ordinators, joint clinics run by paediatric and adult physicians); and service delivery (separate young adult clinics, out of hours phone support, enhanced follow-up). The conditions involved varied (eg, cystic fibrosis, diabetes mellitus), and outcome measures varied accordingly. All six interventions that resulted in significant improvements were in studies of patients with diabetes mellitus, with glycosylated haemoglobin level, acute and chronic complications, and rates of follow-up and screening used as outcome measures.

CONCLUSIONS

The most commonly used strategies in successful programmes were patient education and specific transition clinics (either jointly staffed by paediatric and adult physicians or dedicated young adult clinics within adult services). It is not clear how generalisable these successful studies in diabetes mellitus will be to other conditions.

The impact of CT colonography for colorectal cancer screening on the UK NHS: costs, healthcare resources and health outcomes

BACKGROUND

Biennial faecal occult blood testing (FOBT) for individuals aged 60-69 years is the primary screening tool for colorectal cancer (CRC) in the UK NHS, despite a large number of patients undergoing an unnecessary optical colonoscopy (OC) and evidence from modelling studies to suggest that more cost-effective technologies exist. CT colonography (CTC) is an emerging CRC screening technology with the potential to prevent CRC by detecting pre-cancerous polyps and to detect cancer at an earlier stage.

OBJECTIVE

to assess the impact of introducing CTC into the UK NHS screening programme for CRC on key health outcomes as well as the NHS budget and healthcare resource capacity.

METHODS

a discrete Markov model was used to reflect the natural history of CRC and the impact of three screening scenarios (biennial FOBT with and without CTC triage of patients referred to OC, and CTC every 5 years) on a range of health outcomes, including the incidence and prevalence of CRC, in a hypothetical cohort of individuals. The yearly costs, health outcomes and healthcare resource capacity requirements were estimated over a 10-year period (2009-18).

RESULTS

using CTC to follow up FOBT-positive patients (scenario 2) was less costly than directing all FOBT-positive patients to OC (scenario 1); saving £776 283 over 10 years for 100 000 individuals invited for screening (year 2007 values), primarily by avoiding approximately 1700 OCs, but was estimated to require 2200 additional CT scans. Implementing a programme of 5-yearly CTC as a primary screen is expected to be more expensive than FOBT screening over the short term (driven by high screening and diagnosis costs), despite substantial savings in treatment costs for CRC over the 10-year time horizon of the model and improved health outcomes.

CONCLUSIONS

adding CTC into the existing NHS Bowel Cancer Screening Programme as part of a preventive screening strategy could be less costly to the NHS over the longer term when used to triage FOBT-positive patients to appropriate follow-up. Increased demand for radiology services may be compensated for by reduced demand in endoscopy units.

Evaluating social and behavioural impacts of English smoke-free legislation in different ethnic and age groups: implications for reducing smoking-related health inequalities

OBJECTIVE

To explore social and behavioural impacts of English smoke-free legislation (SFL) in different ethnic groups.

DESIGN

A longitudinal, qualitative panel study of smokers using in-depth interviews conducted before and after introduction of SFL.

PARTICIPANTS

A purposive sample of 32 smokers selected from three ethnic groups in deprived London neighbourhoods with approximately equal numbers of younger and older, male and female respondents.

RESULTS

SFL has had positive impacts with half smoking less and three quitting. Although there were no apparent differences in smoking and quitting behaviours between groups, there were notable differences in the social impacts of SFL. The greatest negative impacts were in smokers over 60 years, potentially increasing their social isolation, and on young Somali women whose smoking was driven more underground. In contrast, most other young adult smokers felt relatively unaffected by SFL, describing unexpected social benefits. Although there was high compliance, reports of illegal smoking were more frequent among young, ethnic minority smokers, with descriptions of venues involved suggesting they are ethnically distinct and well hidden. Half of respondents reported stopping smoking in their own homes after SFL, but almost all were Somali or Turkish. White respondents tended to report increases in home smoking.

DISCUSSION

Although our study suggests that SFL can lead to reductions in tobacco consumption, it also shows that impacts vary by ethnicity, age and sex. This study highlights the importance of understanding the meaning of smoking in different social contexts so future tobacco control interventions can be developed to reduce health and social inequalities.

Hydrological regime and salinity alter the bioavailability of Cu and Zn in wetlands

In the context of the European Water Framework Directive, controlled flooding of lowlands is considered as a potential water management strategy to minimise the risk of flooding of inhabited areas. However, due to historical pollution and overbank sedimentation, metal levels are elevated in most wetlands, which can cause adverse effects on the ecosystem's dynamics. Additionally, salinity affects the bioavailability of metals present or imported into these systems. The effect of different flooding regimes and salinity exposure scenarios (fresh- and brackish water conditions) on Cu and Zn accumulation in the oligochaete Tubifex tubifex (Müller, 1774) was examined. Metal mobility was closely linked to redox potential, which is directly related to the prevalent hydrological regime. Flooded, and thus more reduced, conditions minimized the availability of metals, while oxidation of the substrates during a drier period was associated with a rapid increase of metal availability and accumulation in the oligochaetes.

Cost effectiveness of CT colonography for UK NHS colorectal cancer screening of asymptomatic adults aged 60-69 years

BACKGROUND

Screening of populations at risk for colorectal cancer (CRC) allows the detection and successful treatment of tumours and their precursor polyps. The current UK CRC screening programme is faecal occult blood testing (FOBT), despite evidence from modelling studies to suggest that more cost-effective technologies exist.

OBJECTIVE

To assess the cost effectiveness of CT colonography (CTC) for colorectal cancer screening from the perspective of the UK NHS.

METHODS

A state-transition Markov model was constructed to estimate lifetime costs and health outcomes of a cohort of individuals screened at age 60-69 years using four different CRC screening technologies: FOBT, flexible sigmoidoscopy, optical colonoscopy and CTC.

RESULTS

CTC screening offered every 10 years was cost saving compared with the current UK programme of biennial FOBT screening. This strategy also yielded greater health benefits (QALYs and life-years) than biennial FOBT screening. The model fit observed CRC epidemiology data well and was robust to changes in underlying parameter values. CTC remained cost effective under a range of assumptions in the univariate sensitivity analysis. However, in the probabilistic sensitivity analysis, CTC dominated FOBT in only 5.9% of simulations and was cost effective at a threshold of pound30,000 per QALY gained in 48% of simulations.

CONCLUSIONS

CTC has the potential to provide a cost-effective option for CRC screening in the UK NHS and may be cost saving compared with the current programme of biennial FOBT. Further analysis is required to assess the impact of introducing CTC to the UK CRC screening programme on the NHS budget and capacity.

Cost of illness associated with Niemann-Pick disease type C in the UK

OBJECTIVE

Niemann-Pick disease type C (NP-C) is a rare and devastating genetic disorder characterised by a range of progressive neurological symptoms, which imposes a burden on patients, family members, the healthcare system and society overall. The objective of this study was to assess direct and indirect costs associated with NP-C in the UK.

METHODS

This was a non-interventional, retrospective, cross-sectional cohort study based on responses from patients and/or their carers/guardians recruited from a UK NP-C database. Resource use and direct medical, direct non-medical and indirect costs were evaluated using data collected via postal survey in October 2007, which included a Medical Resource Use questionnaire. Total annual costs per patient were estimated.

RESULTS

In total, 18 Medical Resource Use questionnaires (29% response rate) were received and analysed. The mean total annual cost (SD) of NP-C per patient was 39,168 pounds (50,315 pounds); 46% were direct medical costs, to which home visits and residential care contributed 68% and 15%, respectively. Direct non-medical costs accounted for 24% of the average annual cost per patient, mainly due to specialist education, and indirect costs 30%. If only direct medical costs were considered, the mean annual cost (SD) per patient was reduced to 18,012 pounds (46,536 pounds).

CONCLUSIONS

The direct annual per-patient cost of NP-C illness in 2007 appears moderate when compared with other rare and severely disabling diseases. However, cost estimates may be conservative, since findings are limited by a small sample size, low survey response rate and potential recall bias. As demonstrated by this study, a substantial proportion of the cost is shifted from the healthcare system to the patient, family and non-medical providers. These findings highlight the need for treatments that can slow or stop disease progression in NP-C.

Public health and economic costs of investigating a suspected outbreak of Legionnaires' disease

This paper provides one of the first assessments of the burden of both the public health investigation and the economic costs associated with an apparent outbreak of Legionnaires' disease (LD) in South East London. In addition to epidemiological, microbiological and environmental investigations, we collected data on the staff time and resources committed by the 11 main organizations responsible for managing the outbreak. Of the overall estimated costs of 455,856 pounds, only 14% (64,264 pounds) was spent on investigation and control of the outbreak compared with 86% (391,592 pounds) spent on the hospital treatment of the patients. The time and money spent on public health services in this investigation appear to represent good value for money considering the potential costs of a major outbreak, including the high case-fatality rate in LD generally and the high health-care costs. Further research is needed to determine optimum strategies for the cost-effective use of health system resources in investigations of LD. Whether the threshold for investigation of cases should be based on observed incidence rates or the cost-effectiveness of investigations, or both, should be debated further.

Thinness, overweight and obesity in a national sample of Iranian children and adolescents: CASPIAN Study

BACKGROUND

This study was conducted to assess the national prevalence of different grades of nutritional status (underweight, normal weight, overweight and obesity) among Iranian school-students and to compare the prevalence of overweight and obesity using three different sets of criteria.

METHODS

This cross-sectional national survey was conducted on a representative sample of 21 111 school students including 10 253 boys (48.6%) and 10 858 girls (51.4%) aged 6-18 years, selected by multistage random cluster sampling from urban (84.6%) and rural (15.4%) areas of 23 provinces in Iran The percentage of subjects in the corresponding body mass index (BMI) categories of the Centers of Disease Control and Prevention (CDC), the International Obesity Task Force (IOTF) and the obtained national percentiles were assessed and compared.

RESULTS

There was no gender differences in BMI, but was higher in boys living in urban than in rural areas (18.4 +/- 3.88 vs. 17.86 +/- 3.66 kg/m(2) respectively, P < 0.05). The prevalence of underweight was 13.9% (8.1% of boys and 5.7% of girls) according to the CDC percentiles, and 5% (2.6% of boys and 2.4% of girls) according to the obtained percentiles. According to the CDC, IOTF and national cut-offs, the prevalence of overweight was 8.82%, 11.3% and 10.1% respectively; and the prevalence of obesity was 4.5%, 2.9% and 4.79% respectively. The prevalence of overweight was highest (10.98%) in the 12-year-old group and that of obesity (7.81%) in the 6-year-old group. The kappa correlation coefficient was 0.71 between the CDC and IOTF criteria, 0.64 between IOTF and national cut-offs, and 0.77 between CDC and national cut-offs.

CONCLUSIONS

The findings of this study warrant the necessity of paying special attention to monitoring of the time trends in child obesity based on uniform definitions, as well as to design programmes to prevent and control associated factors.

Maximizing the contribution of the public health workforce: the English experience

In the United Kingdom, until the 1990s, specialist practice of public health was dominated by the medical profession. During the past decade, the contributions to specialist public health practice of people from diverse disciplines have become recognized, respected and valued. In parallel to this paradigm shift in culture in the specialist workforce, recognition is growing of the importance to health improvement of the routine activities of people in other jobs, whose daily work can have a significant impact on population health. These people include public health practitioners, such as environmental health officials, but also others in a very wide range of occupations, from local government chief executive officers to catering assistants, who, although their actions can have a substantial influence on public health, would not traditionally have been viewed as part of the public health workforce. Transforming opportunities for training and professional development to meet the diverse needs of these different groups within the public health workforce for them to recognize and fulfil their potential for health improvement is an important challenge, if we are to achieve continuing improvements in public health. Presenting England's attempts to address the challenges of recruiting and training the range of people needed to deliver effective intersectoral public health may offer insights for those facing similar challenges in other countries.

Influence of calcium, magnesium, sodium, potassium and pH on copper toxicity to barley (Hordeum vulgare)

The extent to which Ca(2+), Mg(2+), Na(+), K(+) ions and pH independently influence copper toxicity to barley (Hordeum vulgare) was assessed by measuring root growth in nutrient solutions. Increased Ca(2+) activity resulted in a sixfold decrease in [EC50(cu2+)] values, while a positive relationship between the cation activity and the EC50 was expected. Increased Mg(2+) activity resulted in a twofold increase in [EC50(cu2+)] values. Na(+), K(+) and H(+) activities did not significantly affect Cu(2+) toxicity. The obtained results indicated that competition for binding sites between Cu(2+) and cations such as Ca(2+), Mg(2+), Na(+), K(+) and H(+) is not an important factor in determining Cu(2+) toxicity to H. vulgare. However, the EC50s could, with one exception, be predicted within a factor three based on the free Cu(2+) activity, indicating that the free Cu(2+) activity cannot only be used to predict metal toxicity to aquatic, but also to terrestrial organisms.

Influence of flooding, salinity and inundation time on the bioavailability of metals in wetlands

Controlled flooding of lowlands is considered as a potential water management strategy to minimize the risk of flooding of inhabited areas during high water periods. However, due to industrial activities, river water, sediments and soils are often contaminated with metals which may have adverse effects on the ecosystem's structure and functioning. Additionally, salinity may greatly affect the bioavailability and toxicity of metals present or imported into these systems. The effect of contaminated soils under different flooding and salinity exposure scenarios on the growth, reproduction and metal accumulation in the oligochaete Tubifex tubifex (Müller, 1774) were examined. In these bioassays metal contaminated soils were flooded with water of different salinities (0 and 3 psu), and tested after 0, 6 and 12 months of permanent inundation. We indeed found that inundation time had significant decreasing effects on Cu and Zn accumulation; although initial accumulation of Cu and Zn was higher in the previously unflooded soil at the start of the flooding treatment, these differences seem to disappear after 6 months of permanent inundation. Moreover, the complex interaction between substrate type and salinity suggests that redox potential is probably of major importance.

Development and validation of a terrestrial biotic ligand model predicting the effect of cobalt on root growth of barley (Hordeum vulgare)

A Biotic Ligand Model was developed predicting the effect of cobalt on root growth of barley (Hordeum vulgare) in nutrient solutions. The extent to which Ca(2+), Mg(2+), Na(+), K(+) ions and pH independently affect cobalt toxicity to barley was studied. With increasing activities of Mg(2+), and to a lesser extent also K(+), the 4-d EC50(Co2+) increased linearly, while Ca(2+), Na(+) and H(+) activities did not affect Co(2+) toxicity. Stability constants for the binding of Co(2+), Mg(2+) and K(+) to the biotic ligand were obtained: logK(CoBL)=5.14, logK(MgBL)=3.86 and logK(KBL)=2.50. Limited validation of the model with one standard artificial soil and one standard field soil showed that the 4-d EC50(Co2+) could only be predicted within a factor of four from the observed values, indicating further refinement of the BLM is needed.

Influence of soil zinc concentrations on zinc sensitivity and functional diversity of microbial communities

Pollution induced community tolerance (PICT) is based on the phenomenon that toxic effects reduce survival of the most sensitive organisms, thus increasing community tolerance. Community tolerance for a contaminant is thus a strong indicator for the presence of that contaminant at the level of adverse concentrations. Here we assessed PICT in 11 soils contaminated with zinc runoff from galvanised electricity pylons and 11 reference soils sampled at 10 m distance from these pylons. Using PICT, the influence of background concentration and bioavailability of zinc on zinc sensitivity and functional diversity of microbial communities was assessed. Zinc sensitivity of microbial communities decreased significantly with increasing zinc concentrations in pore water and calcium chloride extracted fraction while no significant relationship was found with total zinc concentration in the soil. It was also found that functional diversity of microbial communities decreased with increasing zinc concentrations, indicating that increased tolerance is indeed an undesirable phenomenon when environmental quality is considered. The hypothesis that zinc sensitivity of microbial communities is related to background zinc concentration in pore water could not be confirmed.

Expression of CD33-related siglecs on human mononuclear phagocytes, monocyte-derived dendritic cells and plasmacytoid dendritic cells

Siglecs are sialic acid binding Ig-like lectins mostly expressed in the haemopoietic and immune systems. Amongst the 11 human siglecs, there are eight proteins highly related to CD33 which have biochemical features of inhibitory receptors, containing two conserved tyrosine-based inhibitory motifs. Five of these (CD33/siglec-3, -5, -7, -9 and -10) are expressed on circulating monocytes. Here we show that monocytes cultured to differentiate into macrophages using either GM-CSF or M-CSF retained expression of these siglecs and their levels were unaffected following stimulation with LPS. In comparison, monocyte-derived dendritic cells down-modulated siglec-7 and -9 following maturation with LPS. Plasmacytoid dendritic cells in human blood expressed siglec-5 only. On monocytes, siglec-5 was shown to mediate rapid uptake of anti-siglec-5 (Fab)2 fragments into early endosomes. This suggests, in addition to inhibitory signalling, a potential role in endocytosis for siglec-5 and the other CD33-related siglecs. Our results show that siglecs are differentially expressed on mononuclear phagocytes and dendritic cells and that some can be modulated by stimuli that promote maturation and differentiation.

Ecotoxicity of cobalt to the springtail Folsomia candida

Despite growing concern about the potential adverse effects of elevated cobalt concentrations in the environment, hardly any toxicity data are available for terrestrial invertebrates. Therefore, chronic toxicity of cobalt was assessed for the springtail Folsomia candida. The 28-day EC50 for the reproduction of F. candida was 1480 mg Co/kg dry wt in standard artificial soil (OECD) and 409 mg Co/kg dry wt in standard field soil (LUFA 2.2). The difference in toxicity can be explained by the higher pH and cation exchange capacity which decreased cobalt bioavailability in the OECD soil. When expressed as pore water concentrations, 28-day EC50s were similar: 159 mg Co/L in OECD and 174 mg Co/L in LUFA 2.2, which corresponded with calculated Co2+ activities of 0.953 and 1.20 mmol/L, respectively. Although the presented data can be considered as a step forward in the assessment of the potential risk of cobalt in the terrestrial environment, more toxicity data for different species are needed to evaluate the environmental risk of cobalt in soils.

Ganglioside GD3 expression on target cells can modulate NK cell cytotoxicity via siglec-7-dependent and -independent mechanisms

Siglec-7 is a sialic acid binding receptor with inhibitory potential, expressed on human NK cells and monocytes. It has an unusual binding preference for alpha2,8-linked disialic acids, such as those displayed by ganglioside GD3. Here we have investigated whether siglec-7-GD3 interactions are able to modulate NK cell cytotoxicity. Using synthetic polyacrylamide glycoprobes, siglec-7 was found to be masked at the NK cell surface but it could be unmasked by sialidase treatment of NK cells. GD3 synthase-transfected P815 target cells expressed high levels of GD3 and bound strongly to recombinant siglec-7-Fc protein. Surprisingly, GD3 synthase-transfected P815 cells were killed more effectively by untreated cells in a siglec-7-independent manner. However, following sialidase treatment of NK cells, a siglec-7-dependent inhibition of killing was observed. These findings have important implications for NK cell cytotoxicity against tumor cells like melanoma that express high levels of GD3 ganglioside.

Effect of new soil metal immobilizing agents on metal toxicity to terrestrial invertebrates

Application of 5% (w:w) novel metal immobilizing agent reduced the water soluble, the calcium chloride extracted as well as the pore water concentration of zinc in soils from Maatheide, a metal contaminated site in the northeast of Belgium. Addition of the metal immobilizing agents also eliminated acute toxicity to the potworm Enchytraeus albidus and the earthworm Eisenia fetida and chronic toxicity to the springtail Folsomia candida. Cocoon production by E. fetida, however, was still adversely affected. These differences may be explained by the species dependent routes of metal uptake: F. candida is probably mainly exposed via pore water while in E. fetida dietary exposure is probably also important. From these results it is clear that organisms with different exposure routes should be used simultaneously to assess the environmental risk of metal contaminated soils.

Influence of ageing on zinc bioavailability in soils

Currently, soil quality criteria or soil risk assessments of metals are based on laboratory toxicity tests which are carried out in soils freshly spiked with metal salts. With these data, species sensitivity distributions are fitted, from which hazardous concentrations and predicted no effect concentrations are derived. However, due to long-term processes, called ageing, soil metal availability decreases with time. Here we show that pH is the most important parameter determining the effect of ageing on zinc partitioning in soils, with the effect of ageing becoming more important with increasing pH. Furthermore, zinc bioavailability, expressed as the internal zinc concentrations in red clover (Trifolium pratense) is closely related to pore water zinc concentration. In addition, there is a clear dose-response relationship between the survival of the earthworm Eisenia fetida and the calcium chloride-extracted zinc fraction. These results indicate that zinc partitioning can be used to predict zinc bioavailability to terrestrial organisms. However, the use of spiked soils in toxicity assays can result in an over-estimation of the effects of zinc, especially at a high pH.

Mixture toxicity of zinc, cadmium, copper, and lead to the potworm Enchytraeus albidus

Central composite designs were used to develop surface response relationships for predicting the chronic toxicity of mixtures of zinc, cadmium, copper, and lead to the potworm Enchytraeus albidus. Surface response relationships were obtained for all binary mixtures of zinc, cadmium, copper, and lead as well as for mixtures with all four metals. For the binary mixture of zinc and cadmium, this approach and the toxit unit approach gave similar results. However, with the toxit unit approach no such surface response models can be developed. The experimental results indicated that effect predictions based on the concentration addition model were always higher than those obtained with the independent action model. The observed effect was lower than the effect predicted by the concentration addition model for all metal mixtures. Therefore it can be concluded that the concentration addition model represents a reasonable worst-case scenario for the risk assessment of metal mixtures in terrestrial ecosystems.

The effect of lindane on terrestrial invertebrates

Acute and chronic ecotoxicity tests with lindane were carried out using the soil invertebrates Eisenia fetida, Enchytraeus albidus, and Folsomia candida. To assess the influence of soil type on the bioavailability, these tests were carried out in a standard artificial OECD soil and in sandy and loamy field soil. For each species, differences in lindane toxicity were observed for the three soil types. These differences were, however, not related to the organic matter content. The relative differences in lindane toxicity between the soils was species-specific. These results therefore indicate that the pore-water hypothesis, i.e., the pore-water contaminant fraction being the toxicological bioavailable fraction, is not always applicable for organic substances. NOEC, NEC, as well as EC10 data were subsequently used to calculate hazardous concentrations for 5% of the species; this methodology, aimed at setting environmental quality criteria, is discussed.

Multi-generation toxicity of zinc, cadmium, copper and lead to the potworm Enchytraeus albidus

In standard chronic terrestrial toxicity tests with invertebrates, adult organisms are exposed to the contaminants and the number of offspring is quantified. These procedures do not allow the assessment of possible effects on all life stages of the organism, which may lead to an underestimation of the toxicity of the test substance. To evaluate the importance of this issue, the potworm Enchytraeus albidus was exposed to zinc, cadmium, copper and lead for two subsequent generations. Juvenile production was assessed for both generations. Considering the variability of metal toxicity data reported in the literature, it is concluded that the two generation assay did not markedly increase the sensitivity of the standard E. albidus test for the tested metals. Therefore, toxicity data obtained with the proposed test guideline with E. albidus are protective for all life stages.

The effect of ageing on the toxicity of zinc for the potworm Enchytraeus albidus

Different extractable zinc fractions and the ecotoxicity of zinc in Enchytraeus albidus were assessed using freshly spiked artificial soils and spiked soils which had been aged for 8 weeks. Standard artificial Organization for Economic Cooperation and Development (OECD)-soils were aged in four different ways: (1) storing at 20 degrees C; (2) percolation followed by storing at 20 degrees C; (3) alternately heating at 60 degrees C and storing at 20 degrees C; and (4) alternately freezing at -20 degrees C and storing at 20 degrees C. Ageing had no clear influence on the pore water concentration, the water soluble and the calcium chloride extractable fraction of zinc in the artificial soils. Similarly, the 21d LC50 and the 42d EC50(reproduction) for E. albidus were not influenced by the different treatments. This absence of zinc fixation in the artificial soil during ageing was probably due to the use of kaolinite clay in OECD-soil.

Tolerance changes of the potworm Enchytraeus albidus after long-term exposure to cadmium

Cadmium tolerance in Enchytraeus albidus was assessed for non-acclimatised organisms, as well as populations acclimatised for 18 months to 32, 100 and 320 mg Cd/kg dry wt. of standard artificial soil. Despite the increased concentration of metallothionein-like proteins in the acclimatised potworms, no changes in sensitivity to acute and chronic (juvenile production) cadmium toxicity could be observed. The 21-day LC50s ranged from 627 for the non-acclimatised enchytraeids to 748 mg Cd/kg dry wt. for the organisms acclimatised for 18 months to a cadmium concentration of 320 mg/kg dry wt. The 42-day EC50s varied from 96.2 (73.6-115) for the organisms acclimatised to 32 mg Cd/kg dry wt. to 234 (186-290) mg Cd/kg dry wt. for those acclimatised to 100 mg Cd/kg dry wt., while the value was intermediate for the non-acclimatised organisms and those acclimatised to the highest cadmium concentration. The elevated content of metallothionein-like proteins apparently only served for the detoxification of the increased cadmium body burdens.

Ecotoxicity of zinc in spiked artificial soils versus contaminated field soils

Metal bioavailability is influenced by soil characteristics and aging period. In the present study, both factors were modeled by comparing metal bioavailability in spiked artificial soil and historically contaminated field soils. The chronic toxicity of zinc to Folsomia candida in spiked artificial soils could be predicted with a model based on pH, cation exchange capacity, and total zinc concentration. However, this model could not adequately predict chronic zinc toxicity in contaminated field soils. Porewater concentration and water- and calcium chloride-extracted zinc fractions of the contaminated field soils were lower than those predicted using models developed for spiked artificial soils, indicating that the effect of aging on metal bioavailability should be taken into account. The reproduction of F. candida in contaminated field soils was lower than predicted with models developed using zinc concentration in the porewater and the water- and calcium chloride-extracted fractions in spiked artificial soils. This suggests that these fractions are not the only bioavailable zinc fractions and that dietary metal exposure might also be an important route of uptake under environmentally relevant conditions. Aging and dietary uptake should be studied urgently in order to be able to perform effect-based risk assessments of metal contaminated soils.

Cadmium toxicity for terrestrial invertebrates: taking soil parameters affecting bioavailability into account

Acute and chronic ecotoxicity tests with cadmium were conducted with the earthworm Eisenia fetida, the potworm Enchytraeus albidus and the springtail Folsomia candida. To assess the influence of the soil type on cadmium bioavailability, these tests were carried out in a standard artificial soil, in a sandy and a loamy field soil. It was not possible to evaluate the influence of soil parameters on the bioavailability on the basis of the experiments that were conducted in only three different soil types, therefore, literature data were also included. However, even in the same standard artificial soils, toxicity data in the literature for Eisenia fetida and Folsomia candida varied considerably. Consequently, no models could be developed that allow a normalization of the ecotoxicity of cadmium to parameters controlling bioavailability. In contrast to zinc, effect concentrations of cadmium for terrestrial invertebrates were always much higher than background concentrations. As the effect of aging on the bioavailability of cadmium was never taken into account, because toxicity experiments were always carried out in freshly spiked soilds, these effect concentrations may even be regarded as conservative. Furthermore, the zinc-cadmium ratio in soils is usually so high that the risk of zinc ecotoxicity for terrestrial invertebrates will usually be much greater in comparison to cadmium ecotoxicity.