Subjective memory complaints, white matter hyperintensities, and cognitive decline in a population‐based cohort study

Abstract Background Subjective memory complaints (SMCs) are associated with a faster cognitive decline and dementia; whether this relationship results from irreversible structural brain alterations, such as white matter hyperintensities (WMH), requires investigation. We aimed to determine the association of SMCs with WMH and cognitive decline and investigate the role of WMH on the relationship between SMCs and cognitive decline. Method We studied 917 participants (63% African Americans and 60% women) from the population‐based Chicago Health and Aging Project (CHAP), who responded to questions about SMCs, underwent magnetic resonance imaging of the brain, and had valid cognitive data on two or more visits during the follow‐up period. SMCs were obtained by self‐report questionnaire, and based on frequency and severity of concerns, we categorized participants into three groups: not concerned, moderately concerned, and very concerned. Result Of 917 participants eligible for the study, 158 (17.2%) had no SMCs concerns, 671 (73.2%) had moderate concerns, and 88 (9.6%) were very concerned. SMCs were associated with larger WMH volumes and faster cognitive decline. Compared to participants with no concerns, those very concerned had 0.833 (95%CI 0.203, 1.463) units higher WMH volumes and 174% faster cognitive decline (‐0.049; 95%CI ‐0.076, ‐0.022). The association between SMCs and cognitive decline was statistically significant only among individuals with large WMH volumes; that is, very concerned individuals with large WMH volumes had 428% faster cognitive decline annually (‐0.077; 95%CI ‐0.144, ‐0.011) than participants with no concerns. In participants with low volumes of WMH, SMCs were not associated with a faster cognitive decline ( P ‐value = 0.595). Conclusion Our study suggests that SMCs, frequently reported by the elderly, are an important sign of cognitive impairment, especially in people with brain atrophies, such as large WMH volumes.