Obesity and diabetes in middle age may accelerate cognitive decline

Middle-aged people who are obese and have other health problems such as high blood sugar are at greater risk of losing their memory and brain function earlier than normal weight individuals, according to a new study published in the medical journal Neurology.
Scientists from the French medical research institution INSERM and University College London analysed over 6,400 Whitehall civil servants with an average age of 50 over a 10-year period.
At the start of the study, 9 per cent of the participants were obese and 38 per cent were overweight. Of the 582 obese people, 350, or 60 per cent, were classed as ‘metabolically abnormal’, meaning they had at least two of the following risk factors: high blood pressure, low HDL (‘good’) cholesterol; high triglycerides; and diabetes (high blood sugar).
Mental tests were carried out three times over the following 10 years to assess memory and other cognitive skills, and the researchers found that obese participants tended to lose their cognitive abilities faster than those with a normal BMI.
However, the mental decline was fastest in those who also had additional metabolic abnormalities, with these participants experiencing a 22.5 per cent faster decline on their cognitive test scores over the decade than those who were healthy and of normal weight.
Study author Archana Singh-Manoux, PhD, research director at INSERM, said “This study provides evidence against the concept of ‘metabolically healthy obesity’ that has suggested that obese people without metabolic risk factors do not show negative cardiac and cognitive results compared to obese people with other risk factors.”
She added that further research is needed “to look at the effects of genetic factors, and also to take into account how long people have been obese and how long they have had these metabolic risk factors”.