How do Social Inequality and sex impact the relationship between LIfestyle and CAncer (SILICA)?
It’s widely known that certain lifestyle factors such as tobacco and alcohol consumption are related to the risk of developing several types of cancer, yet the role of social inequality, expressed via indicators such as education, occupation, income and sex on modulating these associations is unclear.
The healthy lifestyle index (HLI) is a composite score that combines information on individuals’:
- smoking habits
- alcohol intake
- physical activity level
- and dietary habits.
The index estimates the propensity of individuals to adopt healthy choices with respect to lifestyle factors. Within three large epidemiological studies, namely the European Prospective Investigation into Cancer and Nutrition (EPIC), the UK Biobank (UKB) and the Norwegian Women and Cancer Study (NOWAC), we aim to investigate:
- the relationship between the HLI and the risk of colorectal, lung, pancreatic and upper aero-digestive tract cancers
- and whether these associations vary with respect to socio-economic position (SEP) and sex.
In this manner, we will evaluate whether the association between lifestyle factors and the risk of developing specific cancers differs among socially advantaged and disadvantaged study participants.
In SILICA we plan to use available information on study participants’ education, occupation and income, as these are considered to be the most informative SEP indicators. In addition, we will integrate a wealth of SEP indicators that were collected within the UKB, including information on social/leisure activities, stress, sleep, and individual-level scores on crime, perceived health, housing and the living environment, with area-level indicators, such as the Townsend’s index and the Index of Multiple Deprivation, to provide information on the living context.
All these variables will be used to inform a more nuanced description of participants’ SEP. In SILICA we will also use existing data on metabolic factors in EPIC and UKB to identify biological pathways potentially associated with healthy (or unhealthy) lifestyle profiles. Relating the identified metabolic signatures with risk of specific cancers will shed light on potential (biological) mechanisms that underlie the relationship between lifestyle and cancer, and on whether such mechanisms vary across SEP groups and/or sex.
In SILICA we will estimate the proportion of avoidable cancer cases and the absolute risks of developing specific cancers if healthier choices were implemented among population subgroups with lower and higher SEP, and in men and women. This will help to inform a set of tailored recommendations.
Focusing on the HLI will inform on the relevance of adopting healthy choices with respect to a variety of lifestyle habits, rather than addressing different habits in isolation. As uptake of public health messages may be less effective among individuals with lower SEP, tailored recommendations together with policy changes, accounting for societal and cultural context, should be the target of cancer prevention strategies in the years to come.
In SILICA we will investigate whether metrics of socio-economic position (SEP) and gender affect the relationship between common lifestyle factors and the risk of colorectal, lung, pancreatic, and upper aero-digestive tract cancers.
SILICA will provide the evidence base to inform policy makers to develop tailored cancer prevention recommendations and guidelines targeting specific socio-economic groups
Dr Pietro Ferrari