|Title||Body mass index and risk of dementia: Analysis of individual-level data from 1.3 million individuals.|
|Publication Type||Journal Article|
|Year of Publication||2018|
|Authors||Kivimäki, M, Luukkonen, R, Batty, GD, Ferrie, JE, Pentti, J, Nyberg, ST, Shipley, MJ, Alfredsson, L, Fransson, EI, Goldberg, M, Knutsson, A, Koskenvuo, M, Kuosma, E, Nordin, M, Suominen, SB, Theorell, T, Vuoksimaa, E, Westerholm, P, Westerlund, H, Zins, M, Kivipelto, M, Vahtera, J, Kaprio, J, Singh-Manoux, A, Jokela, M|
INTRODUCTION: Higher midlife body mass index (BMI) is suggested to increase the risk of dementia, but weight loss during the preclinical dementia phase may mask such effects.
METHODS: We examined this hypothesis in 1,349,857 dementia-free participants from 39 cohort studies. BMI was assessed at baseline. Dementia was ascertained at follow-up using linkage to electronic health records (N = 6894). We assumed BMI is little affected by preclinical dementia when assessed decades before dementia onset and much affected when assessed nearer diagnosis.
RESULTS: Hazard ratios per 5-kg/m increase in BMI for dementia were 0.71 (95% confidence interval = 0.66-0.77), 0.94 (0.89-0.99), and 1.16 (1.05-1.27) when BMI was assessed 10 years, 10-20 years, and >20 years before dementia diagnosis.
CONCLUSIONS: The association between BMI and dementia is likely to be attributable to two different processes: a harmful effect of higher BMI, which is observable in long follow-up, and a reverse-causation effect that makes a higher BMI to appear protective when the follow-up is short.
|Alternate Journal||Alzheimers Dement|
|PubMed Central ID||PMC5948099|
|Grant List||MR/K013351/1 / / Medical Research Council / United Kingdom|