“The brain’s ability to function can start to deteriorate as early as 45, suggests a study in the British Medical Journal. University College London researchers found a 3.6% decline in mental reasoning in women and men aged 45–49. They assessed the memory, vocabulary and comprehension skills of 7,000 men and women aged 45 to 70 over 10 years.
The Alzheimer’s Society said research was needed into how changes in the brain could help dementia diagnoses. Previous research had suggested that cognitive decline does not begin much before the age of 60. But the results of this study show that it could in fact begin in middle age.”
Link to Study: Timing of onset of cognitive decline: results from Whitehall II prospective cohort study (BMJ). From the Abstract:
“Objectives: To estimate 10 year decline in cognitive function from longitudinal data in a middle aged cohort and to examine whether age cohorts can be compared with cross sectional data to infer the effect of age on cognitive decline.
Main outcome measure: Tests of memory, reasoning, vocabulary, and phonemic and semantic fluency, assessed three times over 10 years.
Results: All cognitive scores, except vocabulary, declined in all five age categories (age 45–49, 50–54, 55–59, 60–64, and 65–70 at baseline), with evidence of faster decline in older people. In men, the 10 year decline, shown as change/range of test×100, in reasoning was ?3.6% (95% confidence interval ?4.1% to ?3.0%) in those aged 45–49 at baseline and ?9.6% (?10.6% to ?8.6%) in those aged 65–70. In women, the corresponding decline was ?3.6% (?4.6% to ?2.7%) and ?7.4% (?9.1% to ?5.7%). Comparisons of longitudinal and cross sectional effects of age suggest that the latter overestimate decline in women because of cohort differences in education. For example, in women aged 45–49 the longitudinal analysis showed reasoning to have declined by ?3.6% (?4.5% to ?2.8%) but the cross sectional effects suggested a decline of ?11.4% (?14.0% to ?8.9%).
Conclusions: Cognitive decline is already evident in middle age (age 45–49).”
To learn more, click on Building a Cognitive Reserve — Interview with Dr. Yaakov Stern.