Scapegoating, self-confidence and risk comparison : the functionality of risk neutralisation and lay epidemiology by injecting drug users

This paper investigates the competing rationalities of scientific and lay epidemiology and how the tension between the two impacts on the efficacy of health promotion messages for injecting drug users (IDUs). It proposes that behaviours, which may be difficult to understand when viewed at an individual level, are, in fact, rational within particular cultural contexts. The study used qualitative semi-structured interviews with 60 heroin users. A number of different types of risk neutralisation were observed in this group of interviewees, including: scapegoating, self-confidence and risk comparison. Interviewees commonly used lay epidemiology to justify and rationalise their risk neutralisation strategies. The paper provides concrete examples of the ways in which this group of IDUs neutralise risk through the use of these strategies. The findings illustrate how many of the psychological constructs surrounding the perception of risk which focus on individual behaviour are fundamentally simplistic and often unhelpful in understanding the behaviours of this group of people. It is concluded that some ‘risk’ behaviours are often functional and rational within the context of prohibitionist drug policies which create an environment in which the IDU often has little real agency to reduce the risks associated with their drug use.

Psychosocial epidemiology of colorectal cancer

The research explored the role played by personality and stress in the development and progress of colorectal cancer. Personality type was related to health outcomes following diagnosis, and to participation in bowel cancer screening. The personality types also differed in terms of their capacity to deal with stress.

Epidemiology and management of Penaeus monodon farms in Andhra Pradesh, India

Disease outbreaks on shrimp farms studied in Andhra Pradesh were caused mainly by white spot syndrome virus (WSSV) significantly reducing yield. Shrimp seed was the major source of WSSV but several risk factors were also involved. Implementation of better management practices (BMPs) at farm and farm cluster level through formation of Self-Help Groups could significantly improve crop outcomes in farms.

Obesity epidemiology

Although recognised clinically for some time as an important condition that increases risk of ill-health in affected individuals, it is only recently that obesity had been recognised as a population-wide problem that requires preventive action. Obesity is a major contributor to diseases and disability, the associated health costs are enormous and obesity has already reached epidemic proportions in many countries, and incidence is continuing to increase in children and adults. Disturbingly the epidemic is not confined to developed countries, with many developing countries and those in transition affected. While recognised as a major population health problem, our understanding of the causes of the epidemic is poor, there has been relatively little population-based research that has focused on the prevention of unhealthy weight gain, and as a consequence knowledge regarding how and where best to intervene is limited.Revised and updated and now part of the From Aetiology to Public Health series, Obesity Epidemiology provides a scholarly text that assists those concerned with understanding prevalence and trends in obesity; its health, social and economic consequences, the underlying causes of the obesity epidemic, the existing evidence regarding strategies to prevent obesity, and the potential of public health initiatives to impact on the population prevalence of obesity. This edition not only provides a thorough update of the material presented in the previous edition (entitled Obesity Prevention and Public Health), but also includes twelve new chapters that cover the epidemiology of obesity in children and adults, and the potential of public health approaches to its prevention. This book will be of interest to all those working in public health and epidemiology; health policy makers, and clinicians and health practitioners working in the related fields of nutrition, exercise and diabetes.About the seriesBy looking at public health issues from a unique condition-based approach, the innovative From Aetiology to Public Health series examines top public health issues from aetiology through to public health and prevention

The epidemiology of ecstasy use and harms in New South Wales, Australia

Aims:This paper examines the epidemiology of ecstasy use and harm in Australia using multiple data sources.

Design: The data included (1) Australian Customs Service 3,4-methylenedioxymethamphetamine (MDMA) detections; (2) the National Drug Strategy Household and Australian Secondary Student Alcohol and Drug Surveys; (3) data from Australia's ecstasy and Related Drugs Reporting System; (4) the number of recorded police incidents for ecstasy possession and distribution collated by the N.S.W. Bureau of Crime Statistics and Research; (5) the number of calls to the Alcohol and Drug Information Service and Family Drug Support relating to ecstasy; (6) the Alcohol and Other Drug Treatment Services National Minimum Dataset on number of treatment episodes for ecstasy, and (7) N.S.W. Division of Analytical Laboratories toxicology data on number of deaths where MDMA was detected.

Findings: Recent ecstasy use among adults in the general population has increased, whereas among secondary students it has remained low and stable. The patterns of ecstasy consumption among regular ecstasy users have changed over time. Polydrug use and use for extended periods of time (>48 h) remain common among this group. Frequent ecstasy use is associated with a range of risk behaviours and other problems, which tend to be attributed to a number of drugs along with ecstasy. Few ecstasy users present for treatment for problems related to their ecstasy consumption.

Conclusions: Messages and interventions to reduce the risks associated with polydrug use and patterns of extended periods of use are clearly warranted. These messages should be delivered outside of traditional health care settings, as few of these users are engaged with such services.

Application of epidemiology to change health policy : defining age-related thresholds of bone mineral density for primary prevention of fracture

In Australia, benefits for antifracture therapies have been available for patients with osteoporosis and a prior fracture. No benefits were available to those with no prior fracture. We aimed to define, in women with no prior fracture, age-related thresholds of bone mineral density (BMD) associated with fracture risk equivalent to that of women with prior fracture and osteoporosis. A case-control study of women (≥50 yr) was conducted, including 291 fracture cases and 823 controls. BMD was measured at the proximal femur and posterior anterior (PA) spine. A fracture risk score (FRS) for the group with no prior fracture was calculated with discriminant analysis. The thresholds for equivalent fracture risk between those with no prior fracture and those with prior fracture were assessed using logistic regression. Increasing the FRS to +0.98 in women with no prior fracture resulted in equivalent odds of sustaining a fracture to those with prior fracture and osteoporosis. The corresponding T-score thresholds at the spine were −4.6 at 50 yr, −3.9 at 60 yr, −3.1 at 70 yr, and −2.4 at 80 yr. The femoral neck T-score thresholds were lower by 0.5 standard deviation. The high-risk individuals defined by this study should be considered for primary fracture prevention therapy.

Prospects for epigenetic epidemiology

Epigenetic modification can mediate environmental influences on gene expression and can modulate the disease risk associated with genetic variation. Epigenetic analysis therefore holds substantial promise for identifying mechanisms through which genetic and environmental factors jointly contribute to disease risk. The spatial and temporal variance in epigenetic profile is of particular relevance for developmental epidemiology and the study of aging, including the variable age at onset for many common diseases. This review serves as a general introduction to the topic by describing epigenetic mechanisms, with a focus on DNA methylation; genetic and environmental factors that influence DNA methylation; epigenetic influences on development, aging, and disease; and current methodology for measuring epigenetic profile. Methodological considerations for epidemiologic studies that seek to include epigenetic analysis are also discussed.

Effects of infection-induced migration delays on the epidemiology of avian influenza in wild mallard populations

Wild waterfowl populations form a natural reservoir of Avian Influenza (AI) virus, and fears exist that these birds may contribute to an AI pandemic by spreading the virus along their migratory flyways. Observational studies suggest that individuals infected with AI virus may delay departure from migratory staging sites. Here, we explore the epidemiological dynamics of avian influenza virus in a migrating mallard (Anas platyrhynchos) population with a specific view to understanding the role of infection-induced migration delays on the spread of virus strains of differing transmissibility. We develop a host-pathogen model that combines the transmission dynamics of influenza with the migration, reproduction and mortality of the host bird species. Our modeling predicts that delayed migration of individuals influences both the timing and size of outbreaks of AI virus. We find that (1) delayed migration leads to a lower total number of cases of infection each year than in the absence of migration delay, (2) when the transmission rate of a strain is high, the outbreak starts at the staging sites at which birds arrive in the early part of the fall migration, (3) when the transmission rate is low, infection predominantly occurs later in the season, which is further delayed when there is a migration delay. As such, the rise of more virulent AI strains in waterfowl could lead to a higher prevalence of infection later in the year, which could change the exposure risk for farmed poultry. A sensitivity analysis shows the importance of generation time and loss of immunity for the effect of migration delays. Thus, we demonstrate, in contrast to many current transmission risk models solely using empirical information on bird movements to assess the potential for transmission, that a consideration of infection-induced delays is critical to understanding the dynamics of AI infection along the entire flyway.

Introduction to epidemiology

Covers historical development of the field of epidemiology, introduces the basic conept of the rate and discusses the concept of risk in the context of population health in light of chronic and infectious disease.

The epidemiology of cryptosporidiosis in New Zealand, 1997-2006

Aims New Zealand has a high incidence of cryptosporidiosis compared to other developed countries. This study aimed to describe the epidemiology of this disease in detail and to identify potential risk factors.

Methods We analysed anonymous cryptosporidiosis notification (1997–2006) and hospitalisation data (1996–2006). Cases were designated as “urban” or “rural” and assigned a deprivation level based on their home address. Association between disease rates and animal density was studied using a simple linear regression model, at the territorial authority level.

Results Over the 10-year period 1997–2006, the average annual rate of notified cryptosporidiosis was 22.0 cases per 100,000 population. The number of hospitalisations was equivalent to 3.6% of the notified cases. There was only 1 reported fatality. The annual incidence of infection appeared fairly stable, but showed marked seasonality with a peak rate in spring (September–November in New Zealand). The highest rates were among Europeans, children 0–9 years of age, and those living in low deprivation areas. Notification rates showed large geographic variations, with rates in rural areas 2.8 times higher than in urban areas, and with rural areas also experiencing the most pronounced spring peak. At the territorial authority (TA) level, rates were also correlated with farm animal density.

Conclusions Most transmission of Cryptosporidium in New Zealand appears to be zoonotic: from farm animals to humans. Prevention should focus on reducing transmission in rural setting, though more research is needed to identify which strategies are likely to be most effective in that environment.