Cross national comparison of memory function before and after a cancer diagnosis in the United States and England.

OBJECTIVES: The long-term memory aging of middle-aged and older cancer survivors is not fully understood and is largely limited to the United States (US) context. We compared long-term memory trajectories before and after an incident cancer diagnosis with the memory trajectories of similarly aged cancer-free adults in the US and England.

METHODS: Incident cancer diagnosis and memory (immediate and delayed recall) were assessed during biennial interviews in the US Health and Retirement Study (HRS; n = 13,037) and the English Longitudinal Study of Ageing (ELSA; n = 8,579) from 2002 to 2018. Within country, multivariable adjusted linear mixed-effects models estimated the standardized memory trajectories in participants with and without cancer.

RESULTS: Prior to diagnosis, cancer survivors had a memory advantage compared to cancer-free individuals, within each country (difference for cancer survivors in the US: 0.10 SD units [95% CI: 0.05, 0.14] and in England: 0.14 SD units [95% CI: 0.07, 0.20]). Cancer survivors in the US experienced an acute decline in memory function immediately following diagnosis (-0.08 SD units; 95% CI: -0.11, -0.04), which was not experienced by cancer survivors in England (0.01 SD units; 95% CI: -0.04, 0.07). Long-term post-diagnosis memory trajectories were similar for cancer survivors and cancer-free participants alike in both countries.

CONCLUSION: The acute decline in memory function associated with a new cancer diagnosis among cancer survivors in the US, but not England, warrants future studies to investigate explanations for this cross-national difference, such as differences in healthcare systems and treatment.

IMPLICATIONS FOR CANCER SURVIVORS: Results can generate hypotheses to identify contextual risk factors to improve cognitive aging of cancer survivors.