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Biomedical subjects

M Petticrew

Publications and source records attributed to M Petticrew.

At least 19 recordsLinked to original sources

Reducing social inequalities in smoking: can evidence inform policy? A pilot study.

OBJECTIVE: To assess the potential contribution of evidence from existing systematic reviews of effectiveness to answering the question: what works in reducing social inequalities in smoking? DATA SOURCE: The Cochrane Library (2002/4). STUDY SELECTION: Systematic reviews of the effectiveness of community based tobacco control interventions, and all the primary studies included in one of these reviews. DATA EXTRACTION: Reviews and primary studies were assessed for intent to assess the social distribution of intervention effects, information about the social inclusiveness or targeting of interventions, baseline sociodemographic data collected on participants, and estimates of effect size stratified by sociodemographic variables. DATA SYNTHESIS: Only one review aimed to examine outcomes stratified by sex, age or socioeconomic status, and these aims were only achieved with respect to sex. Sociodemographic data about participants were frequently collected in primary studies, but not used to compare intervention effects between social groups. CONCLUSIONS: There may be scope for using existing research more effectively to contribute to evidence based policy to reduce social inequalities in smoking-by explicitly seeking stratified outcome data in new systematic reviews, by re-analysing original datasets, and/or by meta-analysis of individual participant data.

Age Factors↗

Health impact assessment of housing improvements: incorporating research evidence.

BACKGROUND: Health impact assessment (HIA) has been widely recommended for future social policies and investment, such as housing improvement. However, concerns have been raised about the utility and predictive value of an HIA. Use of existing research data would add more weight to forecasts by an HIA. METHODS, RESULTS, and CONCLUSIONS: A recent systematic review of housing intervention studies found a lack of research. The authors recommended that a broader evidence base would be needed to support HIA. In response to consultation with policymakers and HIA practitioners this paper presents a way in which research can be used to inform HIA. Based on the systematic review, the authors have developed a table of synthesised findings indicating the expected health effects of specific housing improvements. The authors also reviewed observational data of housing associated health risks to highlight the key impacts to consider when doing a housing HIA. The findings are presented and the authors discuss how they should be used to inform evidence based housing HIA. In addition to considering the existing research, HIA must consider the local relevance of research. Consultation with local stakeholders also needs to be incorporated to the final assessment. The lack of data and the difficulties in gathering and reviewing data mean that not all HIAs will be able to be informed by research evidence. Well conducted prospective validation of HIAs would contribute to the development of healthy housing investment by informing future housing HIA.

Environmental Health↗

What are the most effective ways of improving population health through transport interventions? Evidence from systematic reviews.

STUDY OBJECTIVE: To review systematic review literature that describes the effectiveness of transport interventions in improving population health. METHODS: Systematic review methodology was used to evaluate published and unpublished systematic reviews in any language that described the measured health effects of any mode of transport intervention. MAIN RESULTS: 28 systematic reviews were identified. The highest quality reviews indicate that the most effective transport interventions to improve health are health promotion campaigns (to prevent childhood injuries, to increase bicycle and motorcycle helmet use, and to promote children's car seat and seatbelt use), traffic calming, and specific legislation against drink driving. Driver improvement and education courses are associated with increases in crash involvement and violations. CONCLUSIONS: Systematic reviews are able to provide evidence about effective ways of improving health through transport related interventions and also identify well intentioned but harmful interventions. Valuable additional information may exist in primary studies and systematic reviews have a role in evaluating and synthesising their findings.

Accidents, Traffic↗

Evidence, hierarchies, and typologies: horses for courses.

Debate is ongoing about the nature and use of evidence in public health decision making, and there seems to be an emerging consensus that the "hierarchy of evidence" may be difficult to apply in other settings. It may be unhelpful however to simply abandon the hierarchy without having a framework or guide to replace it. One such framework is discussed. This is based around a matrix, and emphasises the need to match research questions to specific types of research. This emphasis on methodological appropriateness, and on typologies rather than hierarchies of evidence may be helpful in organising and appraising public health evidence.

Decision Making↗

Assessing the health impact of local amenities: a qualitative study of contrasting experiences of local swimming pool and leisure provision in two areas of Glasgow.

STUDY OBJECTIVE: To assess the health impacts of local public swimming pool and leisure provision. DESIGN: Retrospective qualitative study using focus groups. Reports from two areas with contrasting experience of provision of a public swimming pool (opening and closure) were compared within the context of general reports about health and neighbourhood. SETTING: Two deprived neighbourhoods in south Glasgow. PARTICIPANTS: Local adult residents of mixed ages, accessed through local community groups. MAIN RESULTS: In both areas the swimming pool was reported as an important amenity that was linked to health and wellbeing. However, few residents reported regular use of the pool for physical activity. Use of the pool facility for social contact was directly linked to reports of relief of stress and isolation, and improved mental health. Pool closure was one in a series of amenity closures and area decline and was used to represent other area changes. Health impacts were strongly linked to the pool closure. The pool opening was associated with local area regeneration, similar but less prominent links between swimming pool provision and health were reported. Health benefits of social contact were diffuse and linked to other local amenities as well as the new pool facility. CONCLUSIONS: Although theoretically linked to increased physical activity, the health benefits conveyed by the swimming pool may be more closely linked to the facilitation of social contact, and a supervised facility for young children. The use of qualitative work to investigate area based change provides rich contextual data to strengthen and explain the reported health impacts.

Adult↗

Evaluating non-randomised intervention studies.

OBJECTIVES: To consider methods and related evidence for evaluating bias in non-randomised intervention studies. DATA SOURCES: Systematic reviews and methodological papers were identified from a search of electronic databases; handsearches of key medical journals and contact with experts working in the field. New empirical studies were conducted using data from two large randomised clinical trials. METHODS: Three systematic reviews and new empirical investigations were conducted. The reviews considered, in regard to non-randomised studies, (1) the existing evidence of bias, (2) the content of quality assessment tools, (3) the ways that study quality has been assessed and addressed. (4) The empirical investigations were conducted generating non-randomised studies from two large, multicentre randomised controlled trials (RCTs) and selectively resampling trial participants according to allocated treatment, centre and period. RESULTS: In the systematic reviews, eight studies compared results of randomised and non-randomised studies across multiple interventions using meta-epidemiological techniques. A total of 194 tools were identified that could be or had been used to assess non-randomised studies. Sixty tools covered at least five of six pre-specified internal validity domains. Fourteen tools covered three of four core items of particular importance for non-randomised studies. Six tools were thought suitable for use in systematic reviews. Of 511 systematic reviews that included non-randomised studies, only 169 (33%) assessed study quality. Sixty-nine reviews investigated the impact of quality on study results in a quantitative manner. The new empirical studies estimated the bias associated with non-random allocation and found that the bias could lead to consistent over- or underestimations of treatment effects, also the bias increased variation in results for both historical and concurrent controls, owing to haphazard differences in case-mix between groups. The biases were large enough to lead studies falsely to conclude significant findings of benefit or harm. Four strategies for case-mix adjustment were evaluated: none adequately adjusted for bias in historically and concurrently controlled studies. Logistic regression on average increased bias. Propensity score methods performed better, but were not satisfactory in most situations. Detailed investigation revealed that adequate adjustment can only be achieved in the unrealistic situation when selection depends on a single factor. CONCLUSIONS: Results of non-randomised studies sometimes, but not always, differ from results of randomised studies of the same intervention. Non-randomised studies may still give seriously misleading results when treated and control groups appear similar in key prognostic factors. Standard methods of case-mix adjustment do not guarantee removal of bias. Residual confounding may be high even when good prognostic data are available, and in some situations adjusted results may appear more biased than unadjusted results. Although many quality assessment tools exist and have been used for appraising non-randomised studies, most omit key quality domains. Healthcare policies based upon non-randomised studies or systematic reviews of non-randomised studies may need re-evaluation if the uncertainty in the true evidence base was not fully appreciated when policies were made. The inability of case-mix adjustment methods to compensate for selection bias and our inability to identify non-randomised studies that are free of selection bias indicate that non-randomised studies should only be undertaken when RCTs are infeasible or unethical. Recommendations for further research include: applying the resampling methodology in other clinical areas to ascertain whether the biases described are typical; developing or refining existing quality assessment tools for non-randomised studies; investigating how quality assessments of non-randomised studies can be incorporated into reviews and the implications of individual quality features for interpretation of a review's results; examination of the reasons for the apparent failure of case-mix adjustment methods; and further evaluation of the role of the propensity score.

Bias↗

Health effects of housing improvement: systematic review of intervention studies.

OBJECTIVE: To review the evidence on the effects of interventions to improve housing on health. DESIGN: Systematic review of experimental and non-experimental housing intervention studies that measured quantitative health outcomes. DATA SOURCES: Studies dating from 1887, in any language or format, identified from clinical, social science, and grey literature databases, personal collections, expert consultation, and reference lists. MAIN OUTCOME MEASURES: Socioeconomic change and health, illness, and social measures. RESULTS: 18 completed primary intervention studies were identified. 11 studies were prospective, of which six had control groups. Three of the seven retrospective studies used a control group. The interventions included rehousing, refurbishment, and energy efficiency measures. Many studies showed health gains after the intervention, but the small study populations and lack of controlling for confounders limit the generalisability of these findings. CONCLUSIONS: The lack of evidence linking housing and health may be attributable to pragmatic difficulties with housing studies as well as the political climate in the United Kingdom. A holistic approach is needed that recognises the multifactorial and complex nature of poor housing and deprivation. Large scale studies that investigate the wider social context of housing interventions are required.

Case-Control Studies↗

False-negative results in screening programs. Medical, psychological, and other implications.

OBJECTIVES: Assessment of the appropriateness of screening programs involves consideration of the harms as well as the benefits. These harms include the risk of false-negative results, the consequences of which have remained underinvestigated. This paper reports the results of a systematic literature review that aimed to assess the medical psychological, economic, and legal consequences of false-negative results in national screening programs. METHODS: The review included a comprehensive literature search and contact with experts to identify relevant literature. Most studies that were identified presented only anecdotal evidence. However, thirteen studies presented quantitative information on medical consequences of false negatives, eight studies presented information on psychological consequences, and two studies presented information on economic consequences. RESULTS: The strength of evidence from most of the primary studies was low. There is some evidence, however, that false-negative results may have a large legal impact. There is also a consensus in the literature that false negatives may have a negative impact on public confidence on screening; evidence is however limited. CONCLUSIONS: False negatives are evident even in high-quality screening programs. They may have the potential to delay the detection of breast and cervical cancer, but there is little evidence to help in assessing their psychological consequences. They also may lead to legal action being taken by those affected and may reduce public confidence in screening. Their impact may be reduced by provision of full information to participants about the benefits and limitations of screening programs and by increasing public education on these issues.

False Negative Reactions↗