Lifetime Weight Fluctuations May Predict Dementia Risk

New research suggests that different patterns of changes in body mass index (BMI) over the life course may be an indicator of dementia risk, according to investigators from the Boston University Chobanian and Avedisian School of Medicine as well as the Chinese Academy of Medical Sciences and Peking Union Medical College.¹

Dementia presents a growing public health concern worldwide, with 50 million patients currently affected and an anticipated rise to more than 150 million cases worldwide by 2050. Obesity is also an ongoing global epidemic, and earlier research has suggested that obesity at midlife may lead to an increased risk for dementia; however, any links between BMI and dementia risk remain unclear.¹

Researchers used data from the Framingham Heart Study, which followed a group of participants for 39 years, measuring their weight approximately every 2 to 4 years.1 They chose to restrict the inclusionary age range to participants between 30 and 50 years of age because those younger than 30 years of age remain below the age of typical dementia onset after approximately 4 decades of follow-up. To observe the trajectories of BMI beginning in earlier midlife, they also excluded participants older than 50 years of age at baseline.²

The final study sample was 2405 participants, 76 of whom developed dementia during approximately 4 decades of follow-up. The duration of follow-up was 31.5 years plus or minus 4.6 years for dementia cases, and 32.3 years plus or minus 6.3 years for non-dementia cases. The mean age of dementia diagnosis was 72.2 years, plus or minus 8 years.²

Advancing age was strongly associated with dementia risk, and education years, sex, marital status, or lifestyle factors at baseline were not different between those with and without dementia.2 The investigators also compared different weight patterns (i.e., stable, gain, loss) among those who did and did not develop dementia.¹

According to the study results, they found that the overall trend of declining BMI was associated with a higher risk of developing dementia. However, after further exploration, they found a subgroup with a pattern of initial increasing BMI followed by declining BMI, both during midlife, which appeared to be central to the declining BMI-dementia association.¹

“These findings are important because previous studies that looked at weight trajectories didn’t consider how patterns of weight gain/stability/loss might help signal that dementia is potentially imminent,” said corresponding author Rhoda Au, PhD, a professor of anatomy and neurobiology, in a press release.¹

Monitoring weight can be relatively easy for patients, family members, and health care providers. Monitoring for various risk indicators, including weight patterns, could provide opportunities for earlier interventions that could change the disease trajectory.¹

“If, after a steady increase in weight that is common as one gets older, there is an unexpected shift to losing weight post-midlife, it might be good to consult with one’s health care provider and pinpoint why,” Au said in the press release. “There are some potential treatments emerging where early detection might be critical in the effectiveness of any of these treatments as they are approved and become available.”¹

REFERENCE

1. Patterns of lifespan weight gain/loss may predict dementia risk. News release. EurekAlert; December 15, 2022. Accessed January 4, 2023. https://www.eurekalert.org/news-releases/974293

2. Li J, Liu C, Ang TFA, and Au R. BMI decline patterns and relation to dementia risk across four decades of follow-up in the Framingham Study. Alzheimer’s & Dementia; December 15, 2022. Accessed January 4, 2023. https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/alz.12839