Michael Joffe

Improving health through policies that promote active travel: A review of evidence to support integrated health impact assessment

BACKGROUND Substantial policy changes to control obesity, limit chronic disease, and reduce air pollution emissions, including greenhouse gasses, have been recommended. Transportation and planning policies that promote active travel by walking and cycling can contribute to these goals, potentially yielding further co-benefits. Little is known, however, about the interconnections among effects of policies considered, including potential unintended consequences. OBJECTIVES AND METHODS We review available literature regarding health impacts from policies that encourage active travel in the context of developing health impact assessment (HIA) models to help decision-makers propose better solutions for healthy environments. We identify important components of HIA models of modal shifts in active travel in response to transport policies and interventions. RESULTS AND DISCUSSION Policies that increase active travel are likely to generate large individual health benefits through increases in physical activity for active travelers. Smaller, but population-wide benefits could accrue through reductions in air and noise pollution. Depending on conditions of policy implementations, risk tradeoffs are possible for some individuals who shift to active travel and consequently increase inhalation of air pollutants and exposure to traffic injuries. Well-designed policies may enhance health benefits through indirect outcomes such as improved social capital and diet, but these synergies are not sufficiently well understood to allow quantification at this time. CONCLUSION Evaluating impacts of active travel policies is highly complex; however, many associations can be quantified. Identifying health-maximizing policies and conditions requires integrated HIAs.

Sperm count and chromatin structure in men exposed to inorganic lead: lowest adverse effect levels

Objectives: To obtain knowledge on male reproductive toxicity of inorganic lead at current European exposure levels and to establish lowest adverse effect levels, if any. Methods: A cross sectional survey of the semen of 503 men employed by 10 companies was conducted in the United Kingdom, Italy, and Belgium. The mean blood lead concentration was 31.0 μg/dl (range 4.6–64.5) in 362 workers exposed to lead and 4.4 μg/dl (range below the detection limit of 19.8) in 141 reference workers. Semen volume and sperm concentration were determined in a fresh semen sample according to an agreed protocol subject to quality assurance. The sperm chromatin structure assay (SCSA) was performed at a centralised laboratory. Extraneous determinants including centre, period of sexual abstinence, and age were taken into account in the statistical analysis. If appropriate, possible thresholds were examined by iterative threshold slope linear regression. Results: The median sperm concentration was reduced by 49% in men with blood lead concentration above 50 μg/dl. There was no indication of a linear trend of lower sperm concentration with increasing blood lead values, but threshold slope least square regression identified a blood lead concentration of 44 μg/dl (β=−0.037, F=4.35, p=0.038) as a likely threshold. Abnormal sperm chromatin structure was not related to blood lead concentration, but some indications of deterioration of sperm chromatin was found in men with the highest concentrations of lead within spermatozoa. Biological monitoring data did not indicate long term effects of lead on semen quantity or sperm chromatin. Conclusion: Adverse effects of lead on sperm concentration and susceptibility to acid induced denaturation of sperm chromatin are unlikely at blood lead concentrations below 45 μg/dl. Effects of low level exposure to lead on other measures of testicular function cannot be ruled out.

A time to pregnancy questionnaire designed for long term recall: validity in Oxford, England.

STUDY OBJECTIVE--To establish the degree of validity of data on time to pregnancy, derived retrospectively using a short questionnaire. DESIGN--Information from the questionnaire was compared with data that had been collected concurrently from the same individuals. SETTING AND PARTICIPANTS--Questionnaires were mailed to 1647 women who continue to be followed up by the Oxford Family Planning Association contraceptive study, and a further 424 were approached for personal interview. Response rates were 91% and 79% respectively. MAIN RESULTS--Matching was successful in 91% of pregnancies. Median recall time was 14 years (interquartile range, 11-16 years). At the group level, remarkably good agreement was found between the two sources of information, presented as cumulative percentage distributions of live births. The findings were at least as good with longer recall (> 14 years) as with shorter recall. Digit performance was present to a limited degree. At the individual level, some misclassification was evident, which has implications for statistical power. For detection of clinical infertility (no conception within 12 months), the sensitivity was in the range 67%-91%, and the specificity was 92%-96%. Variations with format, duration of recall, age at delivery, year of birth, parity, social class, smoking habit, last contraceptive method, and outcome (live birth or not) were generally small, and were not statistically significant. CONCLUSIONS--Time to pregnancy is a sensitive way of assessing reproductive function in either sex. Valid data at a group level can be derived retrospectively, with a long duration of recall, using a short questionnaire.

Time trends in biological fertility in Britain.

BACKGROUND There is evidence of a decline in semen quality in some countries, including Britain, in recent decades. This retrospective cohort study examined the hypothesis that biological fertility had also declined. The trend in couple fertility was assessed by means of time to pregnancy (TTP--a sensitive and validated measure of fertility. METHODS A representative sample of the British population aged 16-59 years was surveyed. TTP was obtained for all births conceived after unprotected intercourse that began during 1961-93, excluding contraceptive failures. The sample size was 1540. FINDINGS In contrast to the original hypothesis, this study found that fertility has increased; the rising trend was accompanied by slight dips during 1976-80 and 1986-90. These results were consistent between male and female respondents, and undiminished by adjustment for possible confounding factors. A stronger and more consistent relation was found with the year when unprotected intercourse started (a period effect) than with the year of birth of either partner (a birth cohort effect). INTERPRETATION The findings could not be explained by trends in age at first birth, increased treatment of subfertility, or changes in oral contraceptive use. If a decline in male fertility has occurred, it has been more than compensated for by a countervailing increase in couple fertility.

A global perspective on energy: health effects and injustices.

The exploitation of fossil fuels is integral to modern living and has been a key element of the rapid technological, social, and cultural changes of the past 250 years. Although such changes have brought undeniable benefits, this exploitation has contributed to a burden of illness through pollution of local and regional environments, and is the dominant cause of climate change. This pattern of development is therefore unsustainable at a global level. At the same time, about 2.4 billion of the worlds population, disadvantaged by lack of access to clean energy, are exposed to high levels of indoor air pollutants from the inefficient burning of biomass fuels. Even in high-income countries, many people live in fuel poverty, and throughout the world, increasingly sedentary lifestyles (to which fossil-fuel-dependent transport systems contribute) are leading to chronic disease and injuries. Energy security is also an issue of growing concern to many governments in both the developed and developing world, and a potential source of international tension and conflict. In this Series, we examine the opportunities to improve health, reduce climate effects, and promote development through realistic adjustments in the way energy and food are produced and consumed.

A framework for the evidence base to support Health Impact Assessment

Objective: To introduce a conceptual structure that can be used to organise the evidence base for Health Impact Assessment (HIA). Background: HIA can be used to judge the potential health effects of a policy, programme or project on a population, and the distribution of those effects. Progress has been made in incorporating HIA into routine practice, especially (in the UK) at local level. However, these advances have mainly been restricted to process issues, including policy engagement and community involvement, while the evidence base has been relatively neglected. Relating policies to their impact on health: The key distinctive feature of HIA is that determinants of health are not taken as given, but rather as factors that themselves have determinants. Nine ways are distinguished in which evidence on health and its determinants can be related to policy, and examples are given from the literature. The most complete of these is an analysis of health effects in the context of a comparison of options. A simple model, the policy/risk assessment model (PRAM), is introduced as a framework that relates changes in levels of exposures or other risk factors to changes in health status. This approach allows a distinction to be made between the technical process of HIA and the political process of decision making, which involves lines of accountability. Extension of the PRAM model to complex policy areas and its adaptation to non-quantitative examples are discussed. Issues for the future: A sound evidence base is essential to the long term reputation of HIA. Research gaps are discussed, especially the need for evidence connecting policy options with changes in determinants of health. It is proposed that policy options could be considered as “exposure” variables in research. The methodology needs to be developed in the course of work on specific issues, concentrated in policy areas that are relatively tractable. Conclusions: A system of coordination needs to be established, at national or supranational level, building on existing initiatives. The framework suggested in this paper can be used to collate and evaluate what is already known, both to identify gaps where research is required and to enable an informed judgement to be made about the potential health impacts of policy options. These judgements should be made widely available for policy makers and for those undertaking health impact assessment.

Long-term recall of time-to-pregnancy

OBJECTIVE To validate two versions of a short self-completion questionnaire on time-to-pregnancy. DESIGN Information from the questionnaire was compared with concurrently collected data from the same individuals. POPULATION Questionnaires were sent to 1,647 women who continue to be followed up by the Oxford Family Planning Association Contraceptive Study. Replies were received from 1,498, a response rate of 91.0%. Successful matching was achieved with 1,392 pregnancies that met the study criteria and that had values of time-to-pregnancy in both data sources. Median recall time was 14 years (interquartile range, 11 to 16 years). MAIN OUTCOME MEASURES At the group level, the frequency distributions of time-to-pregnancy from the two sources are presented as cumulative percentages. At the individual level, the distribution of discrepancies between the sources is tabulated separately for each value of time-to-pregnancy, and accuracy of detection of clinical subfertility is presented (sensitivity and specificity). RESULTS At the group level, remarkably good agreement was found between the two sources of information. Digit preference was present to a limited degree. There were no important differences between the two questionnaire versions. At the individual level, some misclassification was evident. For the detection of clinical infertility, sensitivity was 79.9% and specificity was 94.9%. CONCLUSIONS Short, self-completion questionnaires are remarkably accurate for assessing time-to-pregnancy at a group level. Individual-level misclassification is frequent, but detection of clinical subfertility is fairly accurate.

Association of time to pregnancy and the outcome of pregnancy

OBJECTIVE To examine the relationship of subfertility with miscarriage, low birth weight, and preterm delivery. DESIGN Comparison of time to pregnancy distributions between pregnancies that had different outcomes. Three comparisons were made: (a) miscarriages with live births; within live births, (b) low birth weight infant (up to 2,500 grams) or not low birth weight; (c) preterm birth (37 weeks or less) or not preterm. Cox regression was used to adjust for covariates. POPULATION All first pregnancies were analyzed from the National Child Development Study, a large survey of young adults aged 33 years, which is nationally representative of the British-born population. MAIN OUTCOME MEASURES The distribution of the time taken to conceive (time to pregnancy), miscarriage, birth weight, and preterm delivery. RESULTS Pregnancies that ended in miscarriage tended to take 23% longer to conceive, after adjustment for the other variables. Pregnancies that resulted in preterm delivery tended to take 15% longer to conceive. There was no statistically significant association with low birth weight. CONCLUSIONS Delay in time to conception is a risk factor for poor obstetric outcome, irrespective of medical intervention.

The potential contribution of increased vegetable and fruit consumption to health gain in the European Union.

BACKGROUND The risk of many important diseases can be reduced by consuming a diet rich in vegetables and fruit. For this reason the World Health Organization (WHO) recommends a daily intake of more than 400 g person(-1). The pattern of both the supply and intake of vegetables and fruit and the potential health gain achieved by increasing intake in the European Union (EU) and three accession countries are presented in this paper. METHODS Patterns of supply and dietary intake were assessed using (1) FAO food balance sheets, which allow comparison between the levels of supply in countries but do not reflect actual intake; and (2) survey data reflecting dietary intake. Using WHO mortality data for coronary heart and cerebrovascular disease and major cancers up to age 65 years, the number of preventable deaths is estimated, assuming vegetable and fruit consumption were levelled up to that of the highest consuming group, and assuming relative risks of 0.5, 0.7 or 0.9. RESULTS Vegetable and fruit consumption varies considerably between EU Member States. The populations of about half (seven) of the EU Member States have a mean daily intake of less than 275 g. Using the best current estimates of relative risk, over 26,000 deaths before the age of 65 years would be prevented annually in the EU if intake was levelled up to the highest consumption levels (and about double this number of deaths before the age of 75 years). CONCLUSION Increasing the intake of vegetables and fruit is feasible and could result in considerable improvements in public health within the EU. Priority should be given to developing methods that demonstrate the burden of disease caused by too low intakes of vegetables and fruit. This would enable the appropriate social, cultural and economic policies to be developed within the EU.

Enhancing the evidence base for health impact assessment

Health impact assessment differs from other purposes for which evidence is collated in a number of ways, including: the focus on complex interventions or policy and their diverse effects on determinants of health; the need for evidence on the reversibility of adverse factors damaging to health; the diversity of the evidence in terms of relevant disciplines, study designs, quality criteria and sources of information; the broad range of stakeholders involved; the short timescale and limited resources generally available; the pragmatic need to inform decision makers regardless of the quality of the evidence. These have implications for commissioning and conducting reviews. Methods must be developed to: facilitate comprehensive searching across a broad range of disciplines and information sources; collate appropriate quality criteria to assess a range of study designs; synthesise different kinds of evidence; and facilitate timely stakeholder involvement. Good practice standards for reviews are needed to reduce the risk of poor quality recommendations. Advice to decision makers must make explicit limitations resulting from absent, conflicting, or poor quality evidence.