Incidence of dementia in the oldest-old and its relationship with age: The Monzino 80-plus population-based study.
Level 3 - non-randomized controlled study
Prospective population-based observational cohort study
PubMed 31786127 · doi:10.1016/j.jalz.2019.09.083
What was done
The Monzino 80-plus study evaluated dementia incidence in a prospective, population-based cohort of residents aged 80 years and older in Varese province, Italy. Out of 1,371 eligible individuals, 1,294 participants (94.4% participation rate; including 64 centenarians) were followed longitudinally over a 15-year period starting in 2002 to identify incident all-cause dementia cases and model the relationship between age and dementia risk, accounting for competing mortality risk.
What was found
Over 15 years, 584 new cases of all-cause dementia occurred, yielding an overall incidence rate of 7.9 per 100 person-years. Dementia risk increased with age (incidence rate ratio: 1.06), with a cubic model providing the best fit (R² = 0.91–0.96). Cumulative incidences of dementia unadjusted and adjusted for competing mortality risk progressively diverged with advancing age, showing dementia incidence continues to rise in nonagenarians and centenarians.
Why it matters
It provides rare, long-term prospective population data on the oldest-old, indicating that the risk of developing dementia continues to rise at extreme old age and that apparent plateauing is primarily due to competing mortality.
Limits
The abstract lacks confidence intervals for the reported incidence rates and incidence rate ratio, does not report subtype-specific incidence (e.g., Alzheimer's disease), does not detail loss to follow-up over the 15-year follow-up period, and is restricted to a single geographic province in Italy.
Cited by
- supports The likelihood of developing dementia increases the longer a person lives.