Adverse childhood experiences may increase dementia risk

Yukako Tani

Individuals with three or more adverse childhood experiences are at increased risk for dementia in old age, according to results of a large-scale cohort study conducted in Japan and published in JAMA Network Open.

“Early life exposure to adverse childhood experiences, including parental loss, family psychopathology and child maltreatment, may be associated with dementia,” Yukako Tani, PhD, of the department of global health promotion at Tokyo Medical and Dental University, and colleagues wrote. “Direct associations of adverse childhood experiences with dementia can be explained by studying the brain. For example, individuals who experienced adverse childhood experiences show deficits in brain structure and function.”

According to the researchers, prior research has established a link between childhood poverty and increased risk for cognitive impairment that is possibly mediated by individuals’ educational paths. However, little research exists regarding associations between dementia and adverse childhood experiences other than education and poverty. Tani and colleagues addressed this research gap by examining this association among 17,412 Japanese individuals born before 1948 who grew up during and after World War 2. Those included had participated in the Japan Gerontological Evaluation Study — a population-based cohort study of adults aged 65 years or older. The researchers assessed dementia onset through the public long-term care insurance system, as well as adverse childhood experiences before age 18 years using a survey at baseline. Specifically, they looked at parental death, parental divorce, parental mental illness, family violence, physical abuse, psychological neglect and psychological abuse. They classified participants according to the number of adverse childhood experiences — zero, one, two, three or more — and used Cox regression models to estimate hazard ratios for dementia risk.

Tani and colleagues found that dementia occurred in 703 participants during a mean follow-up of 3.2 years. A total of 6,804 (39.1%) were aged older than 75 years. Regarding adverse childhood experiences among all participants, 10,968 (63%) reported zero, 5,129 (29.5%) reported one, 964 (5.5%) reported two and 351 (2%) reported three or more. After adjustment for sex, age, childhood economic hardship, education and nutritional environment (HR = 2.18; 95% CI, 1.42-3.35), those who reported three or more adverse childhood experiences had a greater risk for developing dementia compared with those who reported none. This hazard ratio was attenuated but remained statistically significant (HR = 1.78; 95% CI, 1.15-2.75) after successive adjustment for adult sociodemographic characteristics, health behavior, health status and social relationships.

“These findings may not be generalizable to other generations and cultures,” the researchers wrote. “Further study is warranted to replicate the association of cumulative adverse childhood experiences and dementia in other settings, taking into consideration the mechanisms of sex difference.” – by Joe Gramigna

Disclosures: Tani reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.