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Is the rate of biological ageing, as measured by age at diagnosis of cancer, socio-economically patterned?. Dr. Jean Adams School of Population and Health Sciences University of Newcastle upon Tyne. Hypothesised causal pathway. Psycho- social stress. Rate of biological ageing.
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Is the rate of biological ageing, as measured by age at diagnosis of cancer, socio-economically patterned? Dr. Jean Adams School of Population and Health Sciences University of Newcastle upon Tyne
Hypothesised causal pathway Psycho-social stress Rate of biological ageing Health related behaviours SEP Health Environmental risks and hazards
Biological ageing • Progressive decrease in ability to meet physiological demands • Due to accumulation of cellular damage • Balance between damage and repair • Some factors causing damage socio-economically patterned • Many factors causing damage also associated with disease
Measuring biological ageing • Cancers due to mutations in genes that control cell growth • Genetic mutations are one form of cellular damage • Chronological age at development of cancer may be a good comparative marker of rate of biological ageing
Hypothesis • Age at development of cancer is not socio-economically patterned • Individuals living in more socio-economically deprived circumstances develop cancer earlier in life
Methods • All individuals registered with NYCRIS 1986-95 inclusive with: • Colorectal cancer (ICD-10 C18, C19, C20) • Breast cancer (ICD-10 C50) • Prostate cancer (ICD-10 C61) • Lung cancer (ICD-10 C33, C34) • Age at diagnosis=date at incidence-date of birth • SEP=Townsend Deprivation Score of enumeration district (1991 census)
Exclusions • Key data missing • Death certification only registration • Second primary • Men with breast cancer • Youngest 25% from each group • 144 627 registrations • 39 301 (27.2%) met one or more exclusion criteria • 105 326 included in analysis
Results - analytical *change in age at diagnosis of cancer across IQR of TDS from most affluent to most deprived quintile
Comment • Age at diagnosis not necessarily a good proxy age at development of cancer • SE variations in diagnostic delay? • Controlling for stage/grade at diagnosis has no effect on results • Age at diagnosis of cancer may be poor proxy for rate of biological ageing • Small effect size throughout • Cancer not necessarily homogenous across age and SEP or by ICD category
Conclusions • Tested a complex model of aetiology using routine data from cancer registry • Those from more deprived areas tend to develop prostate, colorectal and lung cancer earlier in life • Those from more deprived areas tend to develop breast cancer later in life • ?due to breast cancer screening programme • Rate of biological ageing may be socio-economically patterned
Acknowledgements • Co-authors • Dr Martin White (Newcastle University) • Prof. David Forman (NYCRIS & Leeds University) • Funding • Faculty of Public Health/BUPA Joint Research Fellowship (2001-04)