Table 1.

Selected Recent Dementia Epidemic Studies

Study/ Authors	Outcome	Data Source	Key Findings	Factors
Manton et al. (USA)	Severe cognitive impairment prevalence	National long- term care survey interviews 1982– 1999	Decline in dementia prevalence in > 65 year olds: 5.7% to 2.9%	Higher education, decline in strokes
Langa et al. (USA)	Cognitive impairment prevalence	US Health and Retirement Study	Cognitive impairment in ≥70-year-olds: 12.2% in 1993 8.7% in 2002	Education; combination of medical, lifestyle, demographic, and social factors
Schrijvers et al. (Rotterdam)	Dementia incidence	Population-based cohort aged 55+ in 1990 extended in 2000	Incidence rate ratios = 6.56 per 1,000 person years in 1990 vs 4.92 in 2000.	Education, reduction in vascular risk, decline in strokes
Qiu et al. (Stockholm)	DSMIII-R dementia prevalence	Cross-sectional survey of 75- year-olds, 1987– 89 and 2001–04	Age- and sex- standardized dementia prevalence: 17.5% in 1987–89 and 17.9% in 2001–04. Lower death hazard rate in later cohort suggests decreased dementia incidence	Favorable changes in risk factors especially vascular risk, and healthier lifestyles
Matthews et al. (CFAS I and II) (England)	Dementia prevalence in 3 regions	Survey interviews of ≥65-year-olds, 1989–94 and 2008–11	Dementia prevalence 8.3% in CFAS I and 6.5% in CFAS II	Higher education, better prevention of vascular disease