Anna Dahl

Overweight in midlife and risk of dementia: a 40-year follow-up study

Objective:This study examines whether overweight in midlife increases dementia risk later in life.Methods:In 1963 body mass index was assessed in 1152 participants of The Swedish Twin Registry, at the age of 45–65 years. These participants were later screened for dementia in a prospective study with up to 40 years follow-up. A total of 312 participants were diagnosed with dementia.Results:Logistic regression analyses adjusted for demographic factors, smoking and alcohol habits, indicated that men and women categorized as overweight in their midlife had an elevated risk of dementia (OR=1.59; 95% CI: 1.21–2.07, P=0.002), Alzheimers disease (OR=1.71; 95% CI: 1.24–2.35, P=0.003), and vascular dementia (OR=1.55; 95% CI: 0.98–2.47, P=0.059). Further adjustments for diabetes and vascular diseases did not substantially affect the associations, except for vascular dementia (OR=1.36; 95% CI: 0.82–2.56, P=0.116), reflecting the significance of diabetes and vascular diseases in the etiology of vascular dementia. There was no significant interaction between overweight and APOE ɛ4 status, indicating that having both risk factors does not have a multiplicative effect with regard to dementia risk.Conclusions:This study gives further support to the notion that overweight in midlife increases later risk of dementia. The risk is increased for both Alzheimers disease and vascular dementia, and follows the same pattern for men and women.

Being Overweight in Midlife Is Associated With Lower Cognitive Ability and Steeper Cognitive Decline in Late Life

BACKGROUND Although an increasing body of evidence links being overweight in midlife with an increased risk for dementia in late life, no studies have examined the association between being overweight in midlife and cognitive ability in late life. Our aim was to examine the association between being overweight in midlife as measured by body mass index (BMI) and cognitive ability assessed over time. METHODS Participants in the Swedish Adoption/Twin Study Aging were derived from a population-based sample. The participants completed baseline surveys in 1963 or 1973 (mean age 41.6 years, range 25-63 years). The surveys included questions about height, weight, diseases, and lifestyle factors. Beginning in 1986, the same individuals were assessed on neuropsychological tests every 3 years (except in 1995) until 2002. During the study period, 781 individuals who were 50 years and older (60% women) had at least one complete neuropsychological assessment. A composite score of general cognitive ability was derived from the cognitive test battery for each measurement occasion. RESULTS Latent growth curve models adjusted for twinness showed that persons with higher midlife BMI scores had significantly lower general cognitive ability and significantly steeper longitudinal decline than their thinner counterparts. The association did not change substantially when persons who developed dementia during the study period were excluded from the analysis. CONCLUSIONS Higher midlife BMI scores precede lower general cognitive ability and steeper cognitive decline in both men and women. The association does not seem to be mediated by an increased risk for dementia.

Overweight and Obesity in Old Age Are Not Associated with Greater Dementia Risk

OBJECTIVES: To describe the association between body mass index (BMI) and dementia risk in older persons.

Agreement between self-reported and measured height, weight and body mass index in old age—a longitudinal study with 20 years of follow-up

BACKGROUND self-reported body mass index (BMI) based on self-reported height and weight is a widely used measure of adiposity in epidemiological research. Knowledge about the accuracy of these measures in late life is scarce. OBJECTIVE the study aimed to evaluate the accuracy and changes in accuracy of self-reported height, weight and BMI calculated from self-reported height and weight in late life. DESIGN a longitudinal population-based study with five times of follow-up was conducted. PARTICIPANTS seven hundred seventy-four community-living men and women, aged 40-88 at baseline (mean age 63.9), included in The Swedish Adoption/Twin Study of Aging. METHODS participants self-reported their height and weight in a questionnaire, and height and weight were measured by experienced research nurses at an in-person testing five times during a 20-year period. BMI was calculated as weight (kilogramme)/height (metre)(2). RESULTS latent growth curve modelling showed an increase in the mean difference between self-reported and measured values over time for height (0.038 cm/year) and BMI (0.016 kg/m(2)/year), but not for weight. CONCLUSIONS there is a very small increase in the mean difference between self-reported and measured BMI with ageing, which probably would not affect the results when self-reported BMI is used as a continuous variable in longitudinal studies.

Body Mass Index, Change in Body Mass Index, and Survival in Old and Very Old Persons

To examine how body mass index (BMI) and change in BMI are associated with mortality in old (70–79) and very old (≥80) individuals.

Body mass index across midlife and cognitive change in late life

Background:High midlife body mass index (BMI) has been linked to a greater risk of dementia in late life, but few have studied the effect of BMI across midlife on cognitive abilities and cognitive change in a dementia-free sample.Methods:We investigated the association between BMI, measured twice across midlife (mean age 40 and 61 years, respectively), and cognitive change in four domains across two decades in the Swedish Adoption/Twin Study of Aging.Results:Latent growth curve models fitted to data from 657 non-demented participants showed that persons who were overweight/obese in early midlife had significantly lower cognitive performance across domains in late life and significantly steeper decline in perceptual speed, adjusting for cardio-metabolic factors. Both underweight and overweight/obesity in late midlife were associated with lower cognitive abilities in late life. However, the association between underweight and low cognitive abilities did not remain significant when weight decline between early and late midlife was controlled for.Conclusion:There is a negative effect on cognitive abilities later in life related to being overweight/obese across midlife. Moreover, weight decline across midlife rather than low weight in late midlife per se was associated with low cognitive abilities. Weight patterns across midlife may be prodromal markers of late life cognitive health.

Overweight in Midlife Is Related to Lower Cognitive Function 30 Years Later : A Prospective Study with Longitudinal Assessments

Aim: To examine if the body mass index (BMI) in midlife is related to cognitive function 30 years later in a dementia-free sample. Methods: BMI was reported in 1963 at age 50–60 years, and cognitive abilities were examined 30 years later in a longitudinal design with 5 measurement occasions at 2-year intervals (n = 417). The cognitive abilities examined included tests of long-term memory, short-term memory, speed, verbal and spatial ability. Results: Multilevel modeling adjusting for demographic and lifestyle factors, and relevant diseases showed that a higher BMI in midlife predicted lower test performance 30 years later. Significant associations between BMI and level of performance were found in all cognitive abilities; however, a higher midlife BMI was not associated with steeper cognitive decline. Conclusion: Our results indicate that midlife overweight is related to lower overall cognitive function in old age. The fact that BMI-related effects were noted in mean-level cognitive performance, whereas only one ability showed differences in slopes, suggests that the negative effect of overweight has an onset before the entry into very old age.

Obesity and Cognitive Aging

Obesity is a health problem that has reached epidemic proportions. Given the high prevalence of obesity, even a small adverse impact of obesity on cognitive aging might have a serious effect on public health. The purpose of this systematic review was to examine the relation between obesity and cognitive function in late life among persons not diagnosed with dementia and to evaluate the evidence for a causal association. Medline was used to search for the following terms: obesity, overweight, cognition, cognitive, age, and aged. To be included, studies must have had a population-based, dementia-free sample and a 5-year minimum interval between measurement of the predictor and the outcome. Only 11 studies met the criteria. Of these, 7 studies assessed obesity in midlife and cognitive function in later life, and 4 studies assessed obesity and cognitive function in late life. The reviewed studies showed clear evidence that midlife obesity was associated with cognitive aging, whereas this association was weaker in late life; thus, no firm conclusions could be drawn. The findings of this review suggest that, although there is evidence for an association between midlife obesity and low cognitive abilities in late life, the direction of the association and the causality remain to be clarified.

Waist‐to‐height ratio is the best indicator for undiagnosed Type 2 diabetes

Early detection of diabetes is important for the prevention of diabetic complications. The best adiposity index for indicating Type 2 diabetes mellitus remains unclear. We aimed to identify the optimal adiposity measure among BMI, waist circumference, waist–hip ratio and waist‐to‐height ratio to indicate undiagnosed Type 2 diabetes and impaired fasting glucose in Chinese adults.

Multifactorial analysis of changes in body mass index across the adult life course: a study with 65 years of follow-up

Background:Although the negative consequences on health of being obese are well known, most adults gain weight across the lifespan. The general increase in body mass index (BMI) is mainly considered to originate from behavioral and environmental changes; however, few studies have evaluated the influence of these factors on change in BMI in the presence of genetic risk. We aimed to study the influence of multifactorial causes of change in BMI, over 65 years.Methods and Findings:Totally, 6130 participants from TwinGene, who had up to five assessments, and 536 from the Swedish Adoption/Twin Study of Aging, who had up to 12 assessments, ranging over 65 years were included. The influence of lifestyle factors, birth cohort, cardiometabolic diseases and an individual obesity genetic risk score (OGRS) based on 32 single nucleotide polymorphisms on change in BMI was evaluated with a growth model. For both sexes, BMI increased from early adulthood to age of 65 years, after which the increase leveled off; BMI declined after age of 80 years. A higher OGRS, birth after 1925 and cardiometabolic diseases were associated with higher average BMI and a steeper increase in BMI prior to 65 years of age. Among men, few factors were identified that influence BMI trajectories in late life, whereas for women type 2 diabetes mellitus and dementia were associated with a steeper decrease in BMI after the age of 65 years.Conclusions:There are two turning points in BMI in late adulthood, one at the age of 65 years and one at the age 80 years. Factors associated with an increase in BMI in midlife were not associated with an increase in BMI after the age of 65 years. These findings indicate that the causes and consequences of change in BMI differ across the lifespan. Current health recommendations need to be adjusted accordingly.