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TOPLINE:

Dementia prevalence among older adults was significantly lower among individuals born more recently (1944-1948) compared to those born earlier (1919-1923), with a more pronounced decline in women, a new study conducted in the US, Europe, and England showed.

METHODOLOGY:

• In this cross-sectional study, data were obtained from the US Health and Retirement Study (HRS; 1994-2021; n = 21,069); the Survey of Health, Aging and Retirement in Europe (SHARE; 2004-2020; n = 32,490); and the English Longitudinal Study of Aging (ELSA; 2002-2019; n = 8878).
• The study focused on individuals aged 71 years or older.
• Validated algorithm and machine learning methods were used to identify individuals with potential dementia.
• Participants were divided into six age groups and assigned to 22 birth cohorts: Eight from HRS, seven from SHARE, and seven from ELSA. The earliest birth cohort in each dataset served as the reference cohort, and all analyses were adjusted for age and period effects.

TAKEAWAY:

• Individuals born between 1944 and 1948 had a significantly lower risk for dementia than those born between 1919 and 1923 across all regions (point estimates: US, -0.55 vs -0.18; Europe, -1.49 vs -0.24; England, -0.48 vs -0.23).
• Women had a more pronounced decrease in dementia risk compared to men in the 1944-1948 birth cohort (point estimates: US, -0.55 vs -0.48; Europe, -1.50 vs -1.34; England, -0.76 vs -0.07).
• Among individuals aged 81-85 years, dementia prevalence varied notably across birth cohorts, with rates in the US declining from 25% (1890-1913 cohort) to 16% (1939-1943 cohort) and in Europe from 30% (1934-1938 cohort) to 15% (1939-1943 cohort).

IN PRACTICE:

“The generational decrease in dementia risk has important implications for healthcare planning, long-term care policies, and workforce requirements in aging populations,” the investigators wrote.

SOURCE:

This study was led by Xiaoxue Dou, Centre for the Business and Economics of Health, The University of Queensland, Brisbane, Australia. It was published online on June 2 in JAMA Network Open.

LIMITATIONS:

Study limitations included incomplete data across survey waves, particularly the omission of SHARE wave 3, and by variable inconsistencies that required algorithm adjustments. Dementia prevalence may have been underestimated due to mortality between waves. Sampling bias was possible, especially owing to the underrepresentation of racial and ethnic minorities in ELSA. The retrospective design also prevented the validation of data collection methods. Additionally, the study did not explore the causes underlying the decline in dementia rates.

DISCLOSURES:

For funding, one investigator reported receiving a PhD scholarship from The University of Queensland. No relevant conflicts of interest were reported.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.