Obesity in middle age increases risk of dementia in later life

A new study shows that being obese in middle age can increase the risk of dementia in later life.

The population based, 27 year longitudinal study, led by Dr Rachel Whitmer, Gerontological Epidemiologist at Kaiser Permanente Division of Research, Oakland California, involved 10,276 members of Kaiser Permanente medical care programme in California who underwent detailed health checks from 1964 to 1973 when they were aged 40-45 and who were still members of the health plan in 1994.

Data on demographics, medical history, medical conditions, body mass index, and skinfold thickness in the shoulders and back of the upper arms area was collected.

In 1994, dementia was diagnosed in 713 (7%) participants and the researchers found that obese people were 74% more likely to have dementia and overweight people were 35% more likely to have dementia when compared with those of normal weight. This appeared to be more so among women.

Obese women were 200% more likely to have dementia than women of normal weight, while obese men had a non-significant 30% increase in risk.

Both men and women with the highest skinfold measurements had a 60-70% greater risk of dementia compared to those with the lowest measurements, no significant race interactions between body mass index and risk of dementia were seen.

An increased risk of dementia is strongly linked to obesity and overweight in middle age regardless of the presence of existing illnesses in mid and late life, say the researchers.

They also state that the study is the first to examine the link between mid-life obesity and dementia and if the results are confirmed elsewhere, the treatment of obesity might reduce the risk of dementia in later life.

The authors conclude that if attempts to contain the present epidemic of obesity fail an increase in dementia can be expected in the future.

The study is published by the British Medical Journal.