Five-Year Change in Body Mass Index Predicts Conversion to Mild Cognitive Impairment or Dementia Only in APOE ɛ4 Allele Carriers.
BACKGROUND
Body mass index (BMI) has been identified as an important modifiable lifestyle risk factor for dementia, but less is known about how BMI might interact with Apolipoprotein E ɛ4 (APOE ɛ4) carrier status to predict conversion to mild cognitive impairment (MCI) and dementia.


OBJECTIVE
The aim of this study was to investigate the interaction between APOE ɛ4 status and baseline (bBMI) and five-year BMI change (ΔBMI) on conversion to MCI or dementia in initially cognitively healthy older adults.


METHODS
The associations between bBMI, ΔBMI, APOE ɛ4 status, and conversion to MCI or dementia were investigated among 1,289 cognitively healthy elders from the National Alzheimer's Coordinating Center (NACC) database.


RESULTS
After five years, significantly more carriers (30.6%) converted to MCI or dementia than noncarriers (17.6%), p < 0.001, OR = 2.06. Neither bBMI (OR = 0.99, 95%CI = 0.96-1.02) nor the bBMI by APOE interaction (OR = 1.02, 95%CI = 0.96-1.08) predicted conversion. Although ΔBMI also did not significantly predict conversion (OR = 0.90, 95%CI = 0.78-1.04), the interaction between ΔBMI and carrier status was significant (OR = 0.72, 95%CI = 0.53-0.98). For carriers only, each one-unit decline in BMI over five years was associated with a 27%increase in the odds of conversion (OR = 0.73, 95%CI = 0.57-0.94).


CONCLUSION
A decline in BMI over five years, but not bBMI, was strongly associated with conversion to MCI or dementia only for APOE ɛ4 carriers. Interventions and behaviors aimed at maintaining body mass may be important for long term cognitive health in older adults at genetic risk for AD.
['Kadey|Kylie R|KR|', 'Woodard|John L|JL|', 'Moll|Allison C|AC|', 'Nielson|Kristy A|KA|', 'Smith|J Carson|JC|', 'Durgerian|Sally|S|', 'Rao|Stephen M|SM|']
D000368:Aged D000483:Alleles D053327:Apolipoprotein E4 D015992:Body Mass Index D060825:Cognitive Dysfunction D003704:Dementia D018450:Disease Progression D005260:Female D006579:Heterozygote D006801:Humans D008297:Male D009483:Neuropsychological Tests
body mass index dementia Alzheimer’s disease Apolipoprotein E4 cognitive dysfunction