Population-wide Changes Research Articles

Situational analysis of infant and young child nutrition policies and programmatic activities in the Islamic Republic of Mauritania.

Progress towards reducing mortality and malnutrition among children <5 years of age has been less than needed to achieve related Millennium Development Goals (MDGs), so several international agencies joined to 'reposition children's right to adequate nutrition in the Sahel', starting with an analysis of current activities related to infant and young child nutrition (IYCN). The main objectives of the situational analysis are to compile, analyse, and interpret available information on infant and child feeding, and the nutrition and health situation of children <2 years of age in Mauritania as one of the six target countries (Burkina Faso, Chad, Mali, Mauritania, Niger, Senegal). These findings are available to assist countries in identifying inconsistencies and filling gaps in current programming. Between August and November of 2008, key informants responsible for conducting IYCN-related activities in Mauritania were interviewed, and 46 documents were examined on the following themes: optimal breastfeeding and complementary feeding practices, prevention of micronutrient deficiencies, prevention of mother-to-child transmission of human immunodeficiency virus (HIV), management of acute malnutrition, food security, and hygienic practices. Mauritania is on track to reaching the MDG of halving undernutrition among children <5 years of age by 2015. National policy documents, training guides, and programmes address nearly all of the key IYCN topics, specifically or generally. Exceptions are the use of zinc supplements in diarrhoea treatment, prevention of zinc deficiency, and dietary guidelines for preventing mother-to-child transmission of HIV. Substantial infrastructure capacity building was also recently implemented in nutritionally high-risk regions, and increases were reported in exclusive breastfeeding rates among children <6 months. The recent National Behaviour Change Communication Strategy is intended to address the needs of adapting programme activities to local needs. Despite these noteworthy accomplishments, the prevalence of acute malnutrition remains high, mortality rates did not decrease as malnutrition rates decreased, the overall prevalence of desirable nutrition-related practices is low, and human resources are reportedly insufficient to carry out all nutrition-related programme activities. Very little nutrition research has been conducted in Mauritania, and key informants identified gaps in adapting international programmes to local needs. Monitoring and evaluation reports have not been rigorous enough to identify which programme activities were implemented as designed or whether programmes were effective at improving nutritional and health status of young children. Therefore, we could not confirm which programmes might have been responsible for the reported improvements, or if other population-wide changes contributed to these changes. The policy framework is supportive of optimal IYCN practices, but greater resources and capacity building are needed to (i) support activities to adapt training materials and programme protocols to fit local needs, (ii) expand and track the implementation of evidence-based programmes nationally, (iii) improve and carry out monitoring and evaluation that identify effective and ineffective programmes, and (iv) apply these findings in developing, disseminating, and improving effective programmes.

Signal production and detection specificity in Vibrio CqsA/CqsS quorum‐sensing systems

SummaryQuorum sensing is a process of bacterial cell–cell communication that enables populations of cells to carry out behaviours in unison. Quorum sensing involves detection of the density-dependent accumulation of extracellular signal molecules called autoinducers that elicit population-wide changes in gene expression. In Vibrio species, CqsS is a membrane-bound histidine kinase that acts as the receptor for the CAI-1 autoinducer which is produced by the CqsA synthase. In Vibrio cholerae, CAI-1 is (S)-3-hydroxytridecan-4-one. The C170 residue of V. cholerae CqsS specifies a preference for a ligand with a 10-carbon tail length. However, a phenylalanine is present at this position in Vibrio harveyi CqsS and other homologues, suggesting that a shorter CAI-1-like molecule functions as the signal. To investigate this, we purified the V. harveyi CqsS ligand, and determined that it is (Z)-3-aminoundec-2-en-4-one (Ea-C8-CAI-1) carrying an 8-carbon tail. The V. harveyi CqsA/CqsS system is exquisitely selective for production and detection of this ligand, while the V. cholerae CqsA/CqsS counterparts show relaxed specificity in both production and detection. We isolated CqsS mutants in each species that display reversed specificity for ligands. Our analysis provides insight into how fidelity is maintained in signal transduction systems.

Urbanization, Physical Activity, and Metabolic Health in Sub-Saharan Africa

OBJECTIVEWe examined the independent associations between objectively measured free-living physical activity energy expenditure (PAEE) and the metabolic syndrome in adults in rural and urban Cameroon.RESEARCH DESIGN AND METHODSPAEE was measured in 552 rural and urban dwellers using combined heart rate and movement sensing over 7 continuous days. The metabolic syndrome was defined using the National Cholesterol Education Program-Adult Treatment Panel III criteria.RESULTSUrban dwellers had a significantly lower PAEE than rural dwellers (44.2 ± 21.0 vs. 59.6 ± 23.7 kJ/kg/day, P < 0.001) and a higher prevalence of the metabolic syndrome (17.7 vs. 3.5%, P < 0.001). In multivariate regression models adjusted for possible confounders, each kJ/kg/day of PAEE was associated with a 2.1% lower risk of prevalent metabolic syndrome (odds ratio 0.98, P = 0.03). This implies a 6.5 kJ/kg/day difference in PAEE, equivalent to 30 min/day of brisk walking, corresponds to a 13.7% lower risk of prevalent metabolic syndrome. The population attributable fraction of prevalent metabolic syndrome due to being in the lowest quartile of PAEE was 26.3% (25.3% in women and 35.7% in men).CONCLUSIONSUrban compared with rural residence is associated with lower PAEE and higher prevalence of metabolic syndrome. PAEE is strongly independently associated with prevalent metabolic syndrome in adult Cameroonians. Modest population-wide changes in PAEE may have significant benefits in terms of reducing the emerging burden of metabolic diseases in sub-Saharan Africa.

Changes in CVD risk factors in the activity counseling trial.

Primary care facilities may be a natural setting for delivering interventions that focus on behaviors that improve cardiovascular disease (CVD) risk factors. The purpose of this study was to examine the 24-month effects of the Activity Counseling Trial (ACT) on CVD risk factors, to examine whether changes in CVD risk factors differed according to baseline risk factor status, and to examine whether changes in fitness were associated with changes in CVD risk factors. ACT was a 24-month multicenter randomized controlled trial to increase physical activity. Participants were 874 inactive men and women aged 35–74 years. Participants were randomly assigned to one of three arms that varied by level of counseling, intensity, and resource requirements. Because there were no significant differences in change over time between arms on any of the CVD risk factors examined, all arms were combined, and the effects of time, independent of arm, were examined separately for men and women. Time × Baseline risk factor status interactions examined whether changes in CVD risk factors differed according to baseline risk factor status. Significant improvements in total cholesterol, high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol, the ratio of total cholesterol to HDL-C, and triglycerides were seen in both men and women who had high (or low for HDL-C) baseline levels of risk factors, whereas significant improvements in diastolic blood pressure were seen only in those men with high baseline levels. There were no improvements in any risk factors among participants with normal baseline levels. Changes in fitness were associated with changes in a number of CVD risk factors. However, most relationships disappeared after controlling for changes in body weight. Improvements in lipids from the ACT interventions could reduce the risk of coronary heart disease in people with already high levels of lipids by 16%–26% in men and 11%–16% in women. Interventions that can be implemented in health care settings nationwide and result in meaningful population-wide changes in CVD risk factors are needed. The ACT physical activity interventions produced substantial improvements among men and women with elevated CVD risk factors.

What Gets Measured, Gets Changed: Evaluating Law and Policy for Maximum Impact

Does law matter regarding public health outcomes? Regardless of what one may think about the answer to this age-old question, in recent years the public health community has increasingly demonstrated and recognized the roles that public health laws and policies play in effectuating long-lasting and broad-based population-wide changes. Public health laws and policies have been instrumental in the following ways: reducing smoking prevalence; reducing underage alcohol-related drinking, driving, crashes, and fatalities; reducing exposure to second-hand smoke; eliminating vaccine–associated paralytic poliomyelitis (VAPP); increasing seat-belt use and reducing traffic fatalities; reducing dental carries; and reducing access to and consumption of unhealthy foods and beverages sold in schools and to reductions in caloric intake and overweight. In fact, in a review of the ten greatest public health achievements in the 20th century, all were influenced by policy change.

Abstract CN05-04: Energy balance within the community: What's new?

Abstract Population-based observational studies have shown remarkably strong and consistent evidence that there is higher risk for many cancer sites among those who carry more body fat and among those who are more sedentary. Obesity is associated with increased risk for cancers of the colorectum, endometrium, esophagus, liver, kidney, pancreas, and gall bladder, and for cancer of the breast among postmenopausal women. Physical activity is associated with reduced risk for cancers of the lung, pancreas, colorectum, endometrium, and both pre-menopausal and post-menopausal breast cancer. The well documented adverse trends in obesity over the past 15 years have occurred in the same era in which both incidence and mortality rates have been declining for breast and colorectal cancer, two of the cancer sites most strongly related to obesity. This apparent contradiction points to the multifactoral causation of these cancers, and suggests that without the headwind of obesity trends, these cancer trends would have been even more favorable. Clearly, physical activity and adiposity are causally linked together. Importantly, however, the relationship between physical activity and cancer does not appear to be due entirely to its relationship with obesity, and the relationship between obesity and cancer does not seem to be due entirely to its relationship with physical activity. The independent and covarying mechanisms that account for the relationships between obesity, physical activity, and cancer risk are not entirely known, but there is ample evidence that these relationships involve multiple pathways, including sex hormones, insulin, insulin-like growth factors, cytokines, and others. Cancer risk seems to be related to energy balance across a wide gradient of levels of adiposity and physical activity that are common in the population. Important for policy and guideline development are the observations that there may be substantial benefits to cancer risk from even small reductions in body fatness and from only small changes in physical activity. Current body weight guidelines and guidelines to increase physical activity to moderate levels, if translated into population-wide changes in behavior, would therefore have substantial impact on cancer risk as well as on risk for diabetes and cardiovascular disease. The needs for research in energy balance are clear: to better understand mechanisms linking adiposity and physical activity to cancer risk by conducting well controlled clinical trials that are powered to assess biomarker relevance directly tied to cancer endpoints. Trials among cancer survivors aimed at elucidating energy balance relationships with recurrence and survival may be more feasible than trials aimed at reducing a first occurrence of cancer incidence. A better understanding of biomarker relationships to energy balance could provide sufficient evidence to negate the need for large scale prevention trials only if those mechanisms paint a picture that is both coherent and compelling. To date, that a picture is unclear. In the meantime, current evidence about the many benefits to quality of life derived from weight control and physical activity and the coherence of evidence relating energy balance to the prevention of cancer, diabetes, and cardiovascular diseases, is already sufficient to more widely institute energy balance interventions as a routine standard for quality clinical care in the population. Citation Information: Cancer Prev Res 2010;3(1 Suppl):CN05-04.

Influence of air pollution on hospital admissions for cardiovascular and respiratory diseases in Nis, Serbia

In studies that investigate the health effects of short-term air pollution exposure, population-wide changes in acute outcomes such as mortality, hospital admissions and healthcare visits are linked to short-term variations in ambient pollutant concentrations. The aim of this study was to estimate the association between daily outdoor black smoke and sulphur dioxide levels and hospital admissions for cardiovascular and respiratory diseases in Nis, within a period 2001-2005. A time series analysis was performed using separated regression models for each pollutant and disease group, by age groups and population as a whole. The effects of copollutant, meteorological factors and cyclic oscillations in hospitalization numbers were controlled. A significant increase in hospital admissions was associated with a 10 microg/m3 increase in the concentration of black smoke, for cardiovascular diseases: 3.14% (< 0.01) in children and youth under 19 years of age, 1.85% (< 0.001) in 19-64 age group, and 0.84% (< 0.05) in all ages, and for respiratory diseases: 1.77% (< 0.05) in 19-64 age group, and 0.91% (< 0.05) in all ages. The effects on hospitalizations for respiratory diseases in children and youth under 19 years of age, and for cardiovascular and respiratory diseases in the elderly were not statistically significant. The increase of sulphur dioxide level was associated with the increased number of hospitalizations, for both cardiovascular and respiratory diseases in all age groups, but the influence was not statistically significant. Outdoor pollutants concentrations in urban area of Nis were below regulated limit values during most of the investigated period days but it is shown that even such a level of pollution has a significant effect on hospital admissions for cardiovascular and respiratory diseases.

Studies needed to address public health challenges of the 2009 H1N1 influenza pandemic: insights from modeling.

The 2009 influenza pandemic (H1N1pdm) has completed its first wave in many northern and southern hemisphere populations and many northern hemisphere populations are reporting substantial activity indicating the start of a second wave this autumn. As the global epidemiology of this novel strain unfolds, substantial policy challenges will continue to present themselves for the next 12 to 18 months. Here, we anticipate six public health challenges and identify data that are required for public health decision making. In particular, we suggest studies that will generate data not otherwise available from routine surveillance. Representative serological surveys stand out as a critical source of data with which to reduce uncertainty around policy choices for both pharmaceutical and non-pharmaceutical interventions after the initial wave has passed. Also, monitoring the time course of incidence of severe H1N1pdm cases will give a clear picture of variability in underlying transmissibility of the virus during population wide changes in behavior such as school vacations and other non-pharmaceutical interventions. In addition, we address low resource settings where routine surveillance for influenza has not been established and suggest alternative ways to collect data for the 2009 (and beyond) influenza H1N1 pandemic.

Assessing Cancer Prevention Studies—A Matter of Time

Assessing Cancer Prevention Studies—A Matter of Time

Rate of change of sickle allele frequency may be influenced by total fertility rate: a sesquicentenary reflection on human micro‐evolution

This article considers the impact of evolutionary forces on the prevalence of sickle cell anemia (SS disease) the most common genetic disease among persons of West African descent living in the Caribbean. It describes the examination of population prevalence and neonatal screening data for Jamaica from different periods and the inability to find any significant decline in sickle (S) allele frequency over the past 22-47 years. It states that their observations on S allele frequency indicate that the combination of improved patient care and population-wide changes in reproductive behavior can have important effects on the genetic makeup of populations.

Population-wide changes in reported lifestyle are associated with redistribution of adipose tissue

The Northern Sweden MONICA project 1986-2004 demonstrated a marked increase in average body mass, an unchanged prevalence of diabetes, and a decrease in myocardial infarctions and lately also in stroke. This study estimates the relative importance of time-trends in lifestyle on average waist and hip circumference on a population level. From a series of independent cross-sectional surveys, a study population of 2,831 men and 2,976 women was formed. Associations between lifestyle factors and waist and hip circumference were estimated. Partial regression coefficients for every level of the lifestyle factors were multiplied by the differences in the proportion of the population reporting the corresponding levels of the respective lifestyle factors in 1986 and 2004. The sum of the product terms for each item represents the respective estimated impact of change in waist and hip circumference. Lifestyle trends associated with changes in hip circumference were (women/men): higher education level (+4.0 mm/+2.4 mm), fewer smokers (+0.4 mm/+0.9 mm), a slight increase in alcohol consumption (+0.4 mm/+0.3 mm), and more saturated fat from meat in women (-0.9 mm) and more fibre from grains in men (+0.6 mm). Average waist circumference was influenced by increased levels of physical activity (-2.2 mm/-4.6 mm), fewer female smokers (-0.3 mm), and a higher intake of saturated fatty acids from meat among men (+1.8 mm). We identified physical activity and the intake of meat and whole-grain products as prime candidates for lifestyle interventions in northern Sweden.

Beyond Established and Novel Risk Factors

Dyslipidemia, hypertension, and diabetes mellitus have been appropriately highlighted as established predictors of cardiovascular disease. These risk factors have become preeminent targets for influencing cardiovascular risk; their assessment, treatment, and monitoring are major emphases of clinical care, research investigation, treatment guidelines, organization position papers, and measures of physician and hospital performance. Notably, lifestyle risk factors, including dietary habits, physical inactivity, smoking, and adiposity, strongly influence the established cardiovascular risk factors and also affect novel pathways of risk such as inflammation/oxidative stress, endothelial function, thrombosis/coagulation, and arrhythmia. Furthermore, modest alterations of these lifestyle risk factors are achievable and have substantial effects on cardiovascular risk. Thus, basic lifestyle habits should be considered fundamental risk factors for cardiovascular disease. Although efforts to combat established and novel risk factors with pharmacological treatments are important and should continue, we call for a systematic rebalancing of current research, clinical care, and policy efforts to focus more on lifestyle. The rising costs of healthcare and the epidemics of overweight and obesity highlight the inadequacies of our current strategy. Substantially more resources should be directed toward research on lifestyle risk factors, their determinants, and effective interventions to change them. The clinical evaluation and treatment of dietary, physical activity, and smoking habits must become as routine and familiar as assessment of blood pressure, cholesterol, and glucose levels. Major policy initiatives and reimbursement guidelines must also be rebalanced to emphasize lifestyle risk factors. Cardiovascular diseases are leading causes of death and disability among men and women in nearly all nations.1 Identification of persons at higher or lower risk for cardiovascular events is important to facilitate effective use of resources and interventions to reduce disease burden among individuals and in society. Each of the established risk factors for cardiovascular disease—age, gender, dyslipidemia, hypertension, diabetes mellitus, and smoking—have been appropriately highlighted …

Monitoring and evaluation of improved biomass cookstove programs for indoor air quality and stove performance: conclusions from the Household Energy and Health Project

Standardized techniques for monitoring and evaluating (M&E) changes in indoor air quality and stove fuel performance were developed and deployed in two NGO-led programs to disseminate improved cookstoves (ICSs) in India and one in Mexico. This paper describes the objectives and characteristics of these monitoring and evaluation methods and how they were deployed. The results showed major and mostly statistically significant improvements in 48-hour indoor air pollution concentrations in those households using the stoves one year after introduction. Kitchen levels of carbon monoxide reduced 30-70% and concentrations of small particles reduced 25-65%. Results for stove performance were mixed, with some stoves achieving improvement in one or another of the short-term metrics that are part of the water boiling test (WBT) used to evaluate stoves in laboratory (controlled) settings. The kitchen performance test, which measures fuel use in households under actual use, was less easily conducted because of high variation and difficult field logistics. The results are more promising, however, with statistically significant reductions in fuel use per person ranging from about 20 to 67%. From the results, it also seems clear that several indicators of stove performance derived from the WBT are not good predictors of actual fuel use and thus should be confined to evaluations during the design stage of stove development. In two of the sites, the reductions in pollution roughly matched those in fuel use, although in the third, indoor air pollution may have reduced a bit more. This indicates perhaps that for all the monitored stoves, much or all of the benefits of each type came from improving the heat transfer into the pots and not from either increased combustion efficiency of the fires or stove-venting (reliably working chimneys). More analyses are planned to explore these and other aspects of the stoves. A range of recommendations are provided for future M&E efforts, with the primary one being to combine efficacy tests (small number of carefully monitored households under normal conditions) with larger well-designed surveys (questionnaire only) to determine actual usage and household perception. It is recommended that only those NGOs planning to develop significant long-term capability in measuring air pollution and stove performance under field conditions be expected to undertake effectiveness testing, i.e., evaluate population-wide changes from real large-scale dissemination programs. The alternative is to employ professional survey and environmental consulting firms, which also has the advantage of assuring independence of the process. In either case, over the long run it is important to generate national capacities for this kind of work.

Wheeling Walks

Mass media community-wide physical activity intervention to promote and sustain changes in walking was assessed using a 2-community longitudinal design. The intervention targeted sedentary 50- to 65-year-old residents of Wheeling, West Virginia. Telephone surveys of a probability sample followed cohorts at baseline and at 3-, 6-, and 12-month post-intervention with comparison communities. The intervention, consisting of paid advertisements, public relations, and community participatory planning, attained high levels of awareness and effected significant sustained population-wide changes among the most sedentary in Wheeling.

Michigan's graduated driver licensing program: Evaluation of the first four years

Introduction: To evaluate the four-year outcome of Michigan's graduated driver licensing (GDL) program, motor-vehicle crash data for 16-year-old drivers in 1996 (pre-GDL), and 1998-2001 (post-GDL) were analyzed. Method: Relative risks and 95% confidence intervals for several crash types were computed, and pre-post-GDL population-based crash rates were compared. Reductions in crash risks among 16-year-olds previously found in 1998 and 1999 were generally maintained in 2000 and 2001. Results: Reductions in crash risk among 16-year-olds from 1996 to 2001 were 29% for all, 44% for fatal, 38% each for nonfatal-injury and fatal-plus-nonfatal-injury, 32% for day, 31% for evening, 59% for night, 32% for single-vehicle, and 28% for multi-vehicle crashes. Even after adjusting for more general population-wide changes among drivers 25 years and older that might have contributed to changes in 16-year-old crash risk, reductions remained impressive (19% for all crashes in 2001). Impact on Industry: As one approach to reducing teenage motor-vehicle morbidity and mortality, GDL remains promising.

Obesity in America

The age-adjusted prevalence of obesity (ie, a body mass index [BMI]30) in the period 1999-2000 (the last official report by the National Health and Nutrition Examination Survey [NHANES III]) was 30.5% compared with 22.9% in 1980. This increase of 8% is part of a continuing trend. Although all changes were not statistically significant, increases occurred in both men and women in all age groups and of all racial and ethnic backgrounds. Among women, obesity was greatest in non-Hispanic African Americans (80% being overweight). Thus, there seem to be populationwide changes. The potential health benefits from reduction in obesity are a matter of considerable public health importance. 1

The effect of risk factor reductions between 1981 and 1990 on coronary heart disease incidence, prevalence, mortality and cost

OBJECTIVESWe sought to estimate the impact and cost-effectiveness of risk factor reductions between 1981 and 1990.BACKGROUNDCoronary heart disease (CHD) mortality rates have declined dramatically, partly as a result of reductions in CHD risk factors.METHODSWe used the CHD Policy Model, a validated computer-simulation model, to estimate the effects of actual investments made to change coronary risk factors between 1981 and 1990, as well as the impact of these changes on the incidence, prevalence, mortality and costs of CHD during this period and projected to 2015.RESULTSObserved changes in risk factors between 1981 and 1990 resulted in a reduction of CHD deaths by ∼430,000 and overall deaths by ∼740,000, with an estimated cost-effectiveness of about $44,000 per year of life saved during this period, based on the estimated actual costs of the interventions used. However, because much of the benefit of risk factor reductions is delayed, the estimated reductions for the 35-year period of 1981 to 2015 were 3.6 million CHD deaths and 1.2 million non-CHD deaths, at a cost of only about $5,400 per year of life saved.CONCLUSIONSAggregate efforts to reduce risk factors between 1981 and 1990 have led to substantial reductions in CHD and should be well worth the cost, largely because of population-wide changes in life-style and habits. Some interventions are much better investments than others, and attention to such issues could lead to better use of resources and better outcomes in the future.

A Contextual Approach to Research on AIDS Prevention

The acquired immune deficiency syndrome (AIDS) is a disease that is transmitted almost entirely through behavioral factors. In the absence of a cure or vaccine, the modification of AIDS-risk behavior presents a unique challenge to behavioral scientists and should be taken as a clear imperative by behavior analysts. This paper discusses the currently dominant social-cognitive theories (the health belief model, the theory of reasoned action, and self-efficacy theory) that have been widely used to predict and understand AIDS-risk behavior. Although these theories have generated a voluminous literature on the cognitive, attitudinal, and demographic correlates of AIDS-risk behavior, they have not resulted in specific intervention strategies to influence risky behavior, most likely because they fail to specify manipulable variables. As an alternative to social-cognitive theories, this paper evaluates the usefulness of a behavior-analytic approach to stem the spread of HIV infection. It examines some of the philosophical differences underlying cognitive and behavioral approaches that are embedded in mechanistic versus functional contextualistic principles. It explores the theoretical and practical implications of adopting either predicting and explaining behavior or predicting and influencing behavior as the goals of science. To illustrate the value of adopting the goal of prediction and influence, behavior-analytic research on the social context of risky sexual behavior in adolescents is described. The paper argues that in order to alter the future course of the AIDS epidemic, the behavioral sciences must move beyond describing cognitive and attitudinal correlates of risky behavior and focus on the social context of the behavior of individuals. In addition, population-wide changes in AIDS-risk behavior can be accomplished only if research focuses on how to influence larger social systems, including the media, school systems, and community organizations.

Normality, deviance and minor psychiatric morbidity in the community. A population-based approach to General Health Questionnaire data in the Health and Lifestyle Survey.

This paper investigates factors affecting the distribution of psychiatric morbidity in the community. It identifies a close relationship between mean Chronic General Health Questionnaire (CGHQ) scores in subdivisions of a large random sample of the community (the Health and Lifestyle Survey, N = 6317) and the prevalence in these groups of abnormal, above-threshold CGHQ scores. The frequency distributions of CGHQ scores in these different populations move up and down as a whole: like other physiological and behavioural attributes, these mental health outcomes in individuals are associated with characteristics of the populations in which they arise. Populations thus carry a collective responsibility for their own mental health and well-being. This implies that explanations for the differing prevalence rates of psychiatric morbidity must be sought in the characteristics of their parent populations; and control measures are unlikely to succeed if they do not involve population-wide changes.

Oesophageal cancer mortality in Europe: paradoxical time trend in relation to smoking and drinking.

The main risk factors for oesophageal cancer previously identified in western Europe are tobacco smoking and alcohol drinking. However, a study of the time trend from 1951 to 1985 of the mortality from oesophageal cancer in 17 European countries shows that, except among the younger age groups in men, oesophageal cancer had either decreased or increased only slightly in most countries. This trend differed from that of lung cancer, cirrhosis and alcohol consumption which had in general increased substantially during the period. The results strongly suggest that population-wide changes in certain undetermined risk/protective factor(s), one possibility of which is the consumption of fruit, had overridden the effect of tobacco and alcohol and resulted in a reduction of oesophageal cancer risk. Apart from further efforts to reduce smoking and drinking, studies to identify the factor(s) will be of great public health importance to the prevention of oesophageal cancer.