Research methods, evidence and public health

In theory, our research questions should drive our choice of method. In practice, we know this is not always the case. At various stages of the research process different factors may apply to restrict the choice of research method. These filters might include a series of inter-related factors such as the political context of the research, the disciplinary affiliation of the researchers, the research setting and peer-review. We suggest that as researchers conduct research and encounter the various filters they come to know the methods that are more likely to survive the filtering process. In future projects they may favour these methods. Public health problems and research questions may increasingly be framed in the terms that can be addressed by a restricted array of methods. Innovative proposals - where new methods are applied to old problems, old methods to new areas of inquiry and high-quality interdisciplinary research - may be unlikely to survive the processes of filtering. This may skew the public health knowledge base, limiting public health action. We argue that we must begin to investigate the process of research. We need to document how and why particular methods are chosen to investigate particular sets of public health problems. This will help us understand how we know what we know in public health and help us plan how we may more appropriately draw upon a range of research methods.

Levels of physical activity for colon cancer prevention compared with generic public health recommendations: population prevalence and sociodemographic correlates

Background: The proportion of Australian adults achieving physical activity levels believed to be sufficient for colon cancer prevention was estimated, and sociodemographic correlates (age, gender, educational attainment, occupation, marital status, and children in household) of meeting these levels of activity were analyzed.

Methods: Data from the 2000 National Physical Activity Survey were used to estimate the prevalence of participation in physical activity in relation to three criteria: generic public health recommendations, weekly amount of at least moderate-intensity physical activity currently believed to reduce risk of colon cancer, and weekly amount of vigorous-intensity physical activity believed to reduce risk of colon cancer.

Results: Overall, 46% of adults met the generic public health criterion, 26% met the colon cancer criterion based on participation in at least moderate-intensity physical activity, and 10% met the colon cancer criterion based on vigorous-intensity physical activity. Women were less likely than men to meet the colon cancer criteria. Younger and more educated persons were more likely to meet all three criteria. The most pronounced differences between gender, age, and educational attainment groups were found for meeting the amount of vigorous-intensity physical activity believed to reduce risk of colon cancer.

Conclusions: The population prevalence for meeting proposed physical activity criteria for colon cancer prevention is low and much lower than that related to the more generic public health recommendations. If further epidemiologic studies confirm that high volumes and intensities of activity are required, the public health challenges for colon cancer will be significant.

Obesity prevention and public health

More than 22 million children under five are now obese or overweight. Globally, an estimated 10% of school-aged children, between five and 17 years old, are overweight or obese, and the situation is getting worse. 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 has 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, 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. This book draws together the existing literature and expertise and with a view to helping set the agenda for public health action. The book is divided into three sections. Part 1 provides an overview of the context of the problem. It examines the epidemiology of obesity, the role of behavioural factors, socio-cultural factors and environmental factors in the obesity epidemic. Part 2 reviews interventions across a range of key settings and in different population groups - drawing on existing research that has aimed to increase physical activity, promote healthy eating and prevent obesity at a population level. Given how little research there is that has specifically examined the effectiveness of interventions aimed at preventing obesity per se, Part 3 explores potential opportunities to prevent obesity

Public health

Public health is crucial for the promotion and protection of health. Links between preventive action and improved health status (eg, in the case of smoking-related cancers, the decline in sudden infant death syndrome and rates of cardiovascular disease) present strong arguments for increased investment in public health infrastructure. The Public Health Education and Research Program has ensured a well-trained public health workforce to support national, state and local initiatives.