Changes in body mass index in young adulthood and late‐life dementia risk in a large diverse cohort: Epidemiology / Risk and protective factors in MCI and dementia. (7th December 2020)

• Record Type: Journal Article
• Authors: Gilsanz, Paola; Mayeda, Elizabeth Rose; George, Kristen M.; Peterson, Rachel; Eng, Chloe W.; Glymour, M Maria; Quesenberry, Charles P; Whitmer, Rachel A.
• Is Part Of: Alzheimer's & dementia. Volume 16(2020)Supplement 10
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-12-07
• Subjects: Alzheimer's disease -- Periodicals; Alzheimer Disease -- Periodicals; Dementia -- Periodicals; Démence; Maladie d'Alzheimer; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); 616.83
• DOI: 10.1002/alz.046496
• Languages: English
• ISSNs: 1552-5260

Abstract

Abstract: Background: Midlife obesity is associated with dementia risk, yet the relationship between body mass index (BMI) during young adulthood and dementia is unclear. Method: We evaluated 6, 947 members of an integrated healthcare delivery system who underwent clinical exams in their 20s and 30s starting in 1964‐1973 and were members as of 1/1/1996. Individuals were classified as underweight (18.5‐25.0 kg/m 2 ), normal weight (18.5‐25.0 kg/m 2 ), overweight (25.0‐30.0 kg/m 2 ), or obese (30+ kg/m 2 ) based on BMI calculated with height and weight measured during the first MHC visit from each age range. Changes in BMI were classified as: 1) consistently normal‐/over‐weight, 2) obesity onset, 3) obese to normal‐/over‐weight, and 4) consistently obese. Dementia diagnoses were abstracted from electronic medical records from 1/1/1997‐9/30/2017. Cox proportional hazard models adjusted for age (as time scale), race/ethnicity, sex, and education evaluated associations between BMI and BMI change categories with dementia risk overall and by sex. Result: The sample was 61.7% female, 6.7% were obese in their 20s, 11.1% were obese in their 30s, and 3.5% experienced dementia during follow‐up. Individuals who were obese in their 20s were at elevated dementia risk (HR=2.14, 95% CI:1.43‐3.20) compared to normal weight counterparts; there was no difference in dementia risk among underweight individuals (HR=0.70, 95% CI:0.31‐1.59) or overweight individuals (HR=1.80, 95% CI 0.79‐1.49). Individuals who were overweight (HR=1.35, 95% CI:1.00, 1.82) and those who were obese (HR=1.76, 95% CI: 1.21‐2.57) in their 30s were at elevated dementia risk compared to normal weight counterparts; there was no association between being underweight and dementia risk (HR=0.59, 95% CI: 0.19‐1.86). Individuals who were consistently obese had more than double the risk of dementia (HR=2.42, 95% CI:1.61‐3.65) than consistently normal‐/over‐weight individuals; there was no association between obesity onset or going from obese to normal‐/over‐ weight and dementia risk. The associations between BMI in one's 20s, BMI in one's 30s, and BMI change with dementia risk did not significantly differ by sex. Conclusion: Obesity during young adulthood (i.e. 20s and 30s) and being overweight during one's 30s were associated with elevated dementia risk. Consistent obesity during young adulthood more than doubled an individual's risk of dementia.