Rachel A Whitmer, Erica P Gunderson, Elizabeth
Barrett-Connor, et al. Obesity in middle age and future risk
of dementia: a 27 year longitudinal population based study.
BMJ 2005;330:1360
Abstract
Objective
To evaluate any association between obesity in middle age,
measured by body mass index and skinfold thickness, and risk
of dementia later in life.
Design
Analysis of prospective data from a multiethnic population
based cohort.
Setting
Kaiser Permanente Northern California Medical Group, a
healthcare delivery organisation.
Participants
10 276 men and women who underwent detailed health
evaluations from 1964 to 1973 when they were aged 40-45 and
who were still members of the health plan in 1994.
Main outcome measures
Diagnosis of dementia from January 1994 to April 2003.
Time to diagnosis was analysed with Cox proportional hazard
models adjusted for age, sex, race, education, smoking,
alcohol use, marital status, diabetes, hypertension,
hyperlipidaemia, stroke, and ischaemic heart disease.
Results
Dementia was diagnosed in 713 (6.9%) participants. Obese
people (body mass index >30) had a 74% increased risk of
dementia (hazard ratio 1.74, 95% confidence interval 1.34 to
2.26), while overweight people (body mass index 25.0-29.9)
had a 35% greater risk of dementia (1.35, 1.14 to 1.60)
compared with those of normal weight (body mass index
18.6-24.9). Compared with those in the lowest fifth, men and
women in the highest fifth of the distribution of subscapular
or tricep skinfold thickness had a 72% and 59% greater risk
of dementia, respectively (1.72, 1.36 to 2.18, and 1.59, 1.24
to 2.04).
Conclusions
Obesity in middle age increases the risk of future
dementia independently of comorbid conditions.
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