BMI Declines Seen Seven Years Before Cognitive Impairment Diagnosis

WEDNESDAY, Nov. 2, 2022 (HealthDay News) -- Significantly lower body mass index (BMI) occurs beginning approximately seven years before a diagnosis of mild cognitive impairment (MCI), according to a study published online Oct. 26 in JAMA Psychiatry.

Jie Guo, M.P.H., from the Karolinska Institutet in Stockholm, and colleagues assessed the long-term BMI trajectories preceding incident MCI and dementia. The analysis included 1,390 participants (mean age, 78.4 years; 76.5 percent female).

The researchers found that compared with participants who remained cognitively intact, BMI tended to decline earlier and faster in those with incident MCI. People with incident MCI had an associated significantly lower BMI from seven years before diagnosis than those who were cognitively intact. However, the slopes of BMI decline did not differ significantly between those with incident MCI who did and did not develop dementia. In a subset of 358 people with autopsy data, BMI was associated with a faster declination among participants with a high burden of global Alzheimer disease pathology or vascular pathology.

"Our findings suggest that the high levels of Alzheimer disease pathology or cerebral vascular disease pathology may be associated with the BMI decline preceding MCI," the authors write. "Future imaging studies (e.g., using positron emission tomography) are warranted to clarify the temporal association between BMI change and brain pathologies."

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