Socioeconomic position and mass media campaigns to prevent chronic disease Robin S Armstrong Master of Applied Science (Research) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy School of Public Health and Social Work and Institute of Health and Biomedical Innovation Faculty of Health Queensland University of Technology March, 2014 Keywords Evaluation, health language, health literacy, health promotion, socioeconomic disadvantage, socioeconomic position, mass media campaign, understanding, chronic disease prevention. Socioeconomic position and mass media campaigns to prevent chronic disease Page i Abstract Background Decades of health promotion efforts aimed at changing health behaviour have resulted in improvements in health, but at a slower pace for lower socioeconomic groups than for their higher socioeconomic counterparts. This slower rate of response by lower socioeconomic groups to health promotion has been said to contribute to a widening gap in health inequality, and mass media health promotion campaigns have been suggested to be a class of interventions that generate health inequality. There is little solid evidence to support these claims, and the methodological rigour of studies that evaluate mass media campaign development and outcomes has been questioned in systematic reviews. The aims of the research presented in this thesis are to ascertain socioeconomic (SEP) differences in mass media campaign outcomes and explore the idea that respondent understanding of campaign messages and language may influence campaign effectiveness. Based on an evaluation framework, the campaign outcomes assessed were reach, understanding and effectiveness. Methods The study was conducted in Brisbane in 2010 following the third wave of the televised component of the Measure Up campaign, part of the Australian Better Health Initiative (ABHI). A random cross-sectional population sample of 1740 adults aged between 45 and 60 years, comparable with Australian Bureau of Statistics (ABS) 2006 Census population characteristics, was invited to complete a mailed survey (response rate 61.4%). For the survey, respondents reported their education, occupation, and yearly household income as measures of socio-economic status. They also were asked questions for assessing campaign reach, understanding of the campaign messages and health-related terminology used in the campaign, and campaign effectiveness. Campaign reach included campaign awareness, and type and number of media channels to which respondents were exposed. Understanding of the message included items about lifestyle-related chronic diseases, as well as the health effects of these conditions and how they may be prevented. Measures of effectiveness included whether respondents agreed that the campaign had prompted them to measure their waist and weight, increase their daily physical activity and Socioeconomic position and mass media campaigns to prevent chronic disease Page ii fruit and vegetable intake, and talk to their doctor about preventing chronic disease. Respondents were also asked whether the campaign had prompted them to visit the campaign website. Cross-tabulations and chi square analyses were used to initially explore relationships between SEP variables and outcome variables. Multivariable logistic regression modelling was then used to examine the likelihood of respondents from each SEP group being aware of the campaign, being exposed via different media channels, having incorrect answers to knowledge items that addressed understanding of the campaign message and health related terminology, and being prompted by the campaign to engage in healthy behaviours and visit the campaign website. Associations between SEP and continuous outcome variables, namely the total number of media channels to which each respondent was exposed (Media Channel Exposure Index) and a total knowledge score (Understanding Index), were analysed using multiple linear regression. Last, mediation effects of the Understanding Index on the relationship between SEP and being prompted to engage in proximal behaviours was examined using logistic regression modelling. Results Reach: In this sample of adults aged 45 to 65 years, 85.8% of respondents were aware of the media campaign, and significant odds of being unaware of the campaign were highest among the least educated, blue collar workers, and respondents with low income. Television was the principal mode of exposure, reaching 93.9% of respondents. Respondents who had a low-middle level of yearly household income were exposed to significantly fewer media channels than were those with a high household income. Understanding: Compared to the higher SEP referent group, low SEP respondents were significantly less likely to give correct answers to knowledge items about the disease process, health effects and preventative lifestyle strategies. For four of five chronic disease risk factors (CDRF), respondents with the lowest education or yearly household income had significantly lower overall understanding of each of the Socioeconomic position and mass media campaigns to prevent chronic disease Page iii CDRF terms. Respondents in the lower socioeconomic groups also showed the least knowledge about the main campaign messages. In all, understanding of campaign terminology was significantly less in lower socioeconomic groups. Effectiveness: Notably, respondents in all levels of education below a bachelor degree were more likely than those with a bachelor or higher degree to report being prompted by the campaign messages to engage in the proximal behaviours. Significant results included respondents with a diploma or an associate degree being significantly more likely than the bachelor degree or higher referent group to be prompted to increase their physical activity, and to increase their fruit and vegetable intake, and those in middle income groups being significantly more likely to be prompted to measure their waist. Low-middle income groups were significantly more likely to increase their fruit and vegetable intake and talk to their doctor about prevention of chronic disease. There were no significant relationships between occupation and effectiveness. Being prompted by the campaign to visit the campaign website was also considered under campaign effectiveness. The majority of respondents in all SEP groups had access to a computer but few visited the campaign website. Highly significant associations were observed between low SEP and not having access to a computer. There were no significant differences among SEP groups in the percentages of participants who had access to a computer but did not go online. Contributions of understanding to effectiveness: There was a statistically significant relationship between understanding and effectiveness but little to suggest that this effect differed by SEP. Those respondents with low overall understanding of the CDRF terms were significantly less likely to measure their waist. Those with low understanding of the term ‘Overweight’ were significantly less likely to measure their weight. Those with low understanding of the term ‘Type 2 Diabetes’ were significantly less likely to increase their fruit and vegetable consumption. However, those with a medium level of understanding of the term ‘Heart Disease’ were 45% more likely to increase their physical activity and 150% more likely to talk to their doctor about preventing chronic disease with both odds ratios statistically significant. Socioeconomic position and mass media campaigns to prevent chronic disease Page iv Conclusion Compared to higher SEP groups, low SEP groups experience significantly lower reach and understanding of mass media health promotion campaign information. In terms of effectiveness, statistically significant odds for respondents with middle income compared to high income were prompted by the Measure Up campaign to measure their waist and weight. These results suggest that the campaign gained the attention of middle, but not higher or lower socioeconomic groups. Understanding was found to influence respondents being prompted to engage in some proximal behaviours but this did not differ by SEP. In the short term, more work needs to be done to determine the health information needs of lower SEP groups as well as the networks by which information is attained and shared. In the longer term, governments need to deliver upstream provision of education systems that will instil a knowledge base on which health knowledge can be built, and mid-stream, by disseminating educationally sound public health information in a manner and format that attracts and can be accessed, understood and acted on by all population groups. Based on the results of this thesis it appears that socioeconomic differences in response to mass media health promotion campaigns may, by way of lower reach and lesser understanding of health related terminology, widen the gaps in health inequality between socioeconomic groups. Socioeconomic position and mass media campaigns to prevent chronic disease Page v Table of Contents Keywords ............................................................................................................. i Abstract ............................................................................................................... ii Table of Contents ................................................................................................. vi List of Figures .....................................................................................................