Building a Weight of Evidence to Prevent Cancer in Later Life

Background: Obesity is the largest preventable risk factor for cancer in the UK after smoking. Being overweight as an adult is linked to 13 types of cancer, and overweight children are more likely to become overweight adults. Routine data shows that around one in three children leave primary school in the UK (aged 12) overweight or obese, with the children from the most deprived communities twice as likely to be so. Cancer Research UK is campaigning for restrictions on the marketing of foods high in salt sugar and fat (HFSS foods) to children as part of a comprehensive population level strategy to prevent obesity-related cancers in the future. Aim: To undertake a mixed methods program of research aimed at building a body of evidence to directly inform policy to address childhood obesity. Methods: Individual studies included: a national cross-sectional survey to investigate obesity and cancer awareness in the UK adult population; a modeling study to predict future obesity-related cancer cases; and qualitative and quantitative studies to explore obesity-linked behaviors and exposure to HFSS marketing in children. A narrative synthesis of results from individual studies was conducted to identify key themes and develop recommendations for policy. Results: Cancer was not at the forefront of people's minds when thinking about obesity, with only 26% of UK adults reporting (unprompted) awareness of the link. However, results from modeling identified that the projected impact of obesity on cancer is high: if current trends continue it will lead to a further 670,000 cases in the UK over the next 20 years. Qualitative research identified a high awareness of junk food marketing in children aged 8-19. This influenced their behavior using a variety of persuasive marketing techniques, including catchy slogans and jingles, celebrity endorsements or by referencing youth culture. Logistic regression modeling associated commercial TV screen time with an increased risk of high junk food consumption (OR 1.8, P = 0.002). Furthermore, recalling one extra broadcast advert predicted a significant increase in HFSS consumption, approximately 18,000 extra calories/person/year. Conclusion: These linked studies have informed Cancer Research UK's campaign on obesity, and results have been used to inform work with the media, coalition building and influencing. Findings that HFSS food marketing influenced children's consumption behaviors were published on the charity's lobbying day in parliament where the research was discussed with almost 170 members of parliament. To achieve further HFSS marketing restrictions, research evidence is essential to making the case for policy change and this approach from a large UK cancer charity could inform similar efforts in other countries.