Body mass index, diet, physical inactivity, and the incidence of dementia in 1 million UK women
Open Access
- 14 January 2020
- journal article
- research article
- Published by Ovid Technologies (Wolters Kluwer Health) in Neurology
- Vol. 94 (2), e123-e132
- https://doi.org/10.1212/wnl.0000000000008779
Abstract
Objective To help determine whether midlife obesity is a cause of dementia and whether low body mass index (BMI), low caloric intake, and physical inactivity are causes or merely consequences of the gradual onset of dementia by recording these factors early in a large 20-year prospective study and relating them to dementia detection rates separately during follow-up periods of Methods A total of 1,136,846 UK women, mean age 56 (SD 5) years, were recruited in 1996 to 2001 and asked about height, weight, caloric intake, and inactivity. They were followed up until 2017 by electronic linkage to National Health Service records, detecting hospital admissions with mention of dementia. Cox regression yielded adjusted rate ratios (RRs) for first dementia detection during particular follow-up periods. Results Fifteen years after the baseline survey, only 1% were lost to follow-up, and 89% remained alive with no detected dementia, of whom 18,695 had dementia detected later, at a mean age of 77 (SD 4) years. Dementia detection during years 15+ was associated with baseline obesity (BMI 30+ vs 20–24 kg/m2: RR 1.21, 95% confidence interval 1.16–1.26, p < 0.0001) but not clearly with low BMI, low caloric intake, or inactivity at baseline. The latter 3 factors were associated with increased dementia rates during the first decade, but these associations weakened substantially over time, approaching null after 15 years. Conclusions Midlife obesity may well be a cause of dementia. In contrast, behavioral changes due to preclinical disease could largely or wholly account for associations of low BMI, low caloric intake, and inactivity with dementia detection during the first decade of follow-up.Keywords
This publication has 25 references indexed in Scilit:
- Identifying dementia outcomes in UK Biobank: a validation study of primary care, hospital admissions and mortality dataEuropean Journal of Epidemiology, 2019
- Cohort Profile: the Million Women StudyInternational Journal of Epidemiology, 2018
- Body-mass index and all-cause mortality: individual-participant-data meta-analysis of 239 prospective studies in four continentsThe Lancet, 2016
- Validity over time of self-reported anthropometric variables during follow-up of a large cohort of UK womenBMC Medical Research Methodology, 2015
- BMI and risk of dementia in two million people over two decades: a retrospective cohort studyThe Lancet Diabetes & Endocrinology, 2015
- Does physical activity prevent cognitive decline and dementia?: A systematic review and meta-analysis of longitudinal studiesBMC Public Health, 2014
- Reported frequency of physical activity in a large epidemiological study: relationship to specific activities and repeatability over timeBMC Medical Research Methodology, 2011
- Epidemiological Studies of the Effect of Stroke on Incident DementiaStroke, 2010
- Reproducibility of a short semi-quantitative food group questionnaire and its performance in estimating nutrient intake compared with a 7-day diet diary in the Million Women StudyPublic Health Nutrition, 2005
- A 32-Year Prospective Study of Change in Body Weight and Incident DementiaArchives of Neurology, 2005