Birth in areas with high infant mortality rates (IMRs) has been linked to worse long-term health outcomes, yet it is completely unknown if it impacts dementia risk.
In total 6268 health care members were followed for dementia diagnosis from 1996 to 2015. Birth state IMRs from 1928 were ranked into quartile (worst IMRs quartile range, whites: 69 to 129 deaths/1000 live births, Non-whites: 129 to 277 deaths/1000 live births). Cox proportional hazard models estimated the dementia risk associated with birth state IMR quartile adjusting for demographics and lifecourse health indicators.
Compared with whites born outside of states in the worst IMR quartile, African Americans born in states in the worst IMR quartile had 92% increased dementia risk (HR=1.92; 95% CI: 1.42, 2.59), and African Americans born outside those states had 36% increased risk (HR=1.36; 95% CI: 1.20, 1.53). There was no association between birth state IMR and dementia risk among whites.
Birth in states with the highest rates of infant mortality was associated with elevated dementia risk among African Americans but not whites. The large absolute difference in IMRs likely reflects harsher early childhood conditions experienced by African Americans. These findings suggest that childhood conditions may play a role in racial disparities in dementia rates.
*Kaiser Permanente Division of Research, Oakland
†Department of Epidemiology, University of California, Los Angeles Fielding School of Public Health, Los Angeles
‡Department of Epidemiology and Biostatistics, University of California, San Francisco
§Department of Neurology, University of California, Davis, Sacramento
∥Department of Public Health, University of California, Davis, CA
Supported by grants number RF1 AG052132 (R.A.W.), R01 AG050782 (R.A.W.), P30 AG010129 (C.S.D.), and R00 AG053410 (E.R.M.) from the National Institute on Aging, National Institutes of Health. P.G. was supported by the UCSF Training for Research on Aging and Chronic Disease (T32 AG049663).
The authors declare no conflicts of interest.
Reprints: Paola Gilsanz, ScD, Kaiser Permanente Division of Research, Behavioral and Mental Health and Aging Section, 2000 Broadway, Oakland, CA 94612 (e-mail: Paola.Gilsanz@kp.org).
Received April 27, 2018
Accepted July 11, 2018