Cognition and mortality from the major causes of death: the Health and Lifestyle Survey.

OBJECTIVE: To investigate the influence of reaction time and cognition on the risk of death from cause-specific mortality and to examine whether any association found remains after adjustment for available socioeconomic, lifestyle, and health factors.
METHODS: Participants were from the UK Health and Lifestyle Survey. The sample consisted of 6424 community dwelling individuals aged between 18 and 97 years at baseline (1984/1985). Sociodemographic, lifestyle, health, and physiological information was collected alongside cognitive testing which included simple (SRT) and choice (CRT) reaction time, a short-term memory test, and a test of visual-spatial reasoning. Participants have been followed for 21 years for cause-specific mortality.
RESULTS: Slower and more variable reaction times and poorer cognitive performance were associated with a higher risk of death from cardiovascular disease, stroke, and respiratory disease after controlling for age and sex. Slight attenuation was noted after adjustments for all covariates. However, only CRT mean remained significantly associated with death from respiratory disease. No associations were found for coronary heart disease, lung cancer, and all nonlung cancers. Significant cognition-mortality associations were mostly obtained in those aged over 60 years. The possibility of reverse causality was partly excluded by reanalysing the data after omitting individuals who died within 5 years of cognitive testing.
CONCLUSIONS: Slower and more variable reaction times and poorer cognitive performance were related to an increased risk of mortality from cardiovascular disease, stroke, and respiratory disease. The possibility of reverse causality requires further testing.