British Medical Journal – Timing of onset of cognitive decline: results from Whitehall II prospective cohort study University College London researchers found a 3.6% decline in mental reasoning in women and men aged 45-49.
Tests of memory, reasoning, vocabulary, and phonemic and semantic fluency, assessed three times over 10 years.
Decline in cognitive test scores over 10 years (% change=change/range of text×100) as function of baseline age cohort in men and women, estimated from linear mixed models. P values denote test for linear trend across age categories, derived by entering them as continuous variable
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%).
“Although we don’t yet have a sure-fire way to prevent dementia, we do know that simple lifestyle changes – such as eating a healthy diet, not smoking, and keeping blood pressure and cholesterol in check – can all reduce the risk of dementia.”
Professor Lindsey Davies, president of the Faculty of Public Health, said that people should not wait until their bodies and minds broke down before taking action.
“We need only look at the problems that childhood obesity rates will cause if they are not addressed to see how important it is that we take ‘cradle to grave’ approach to public health.”