Obesity accelerates senile decline of thinking abilities
Scientists at the INSERM Research Institute in Paris analyzed data on 6,401 people who took part in the Second Whitehall Study of British civil servants.
71% of the participants were men whose average age at the time of the start of participation in the study (1991-1992) was 50 years. Among other things, at this stage, data were collected concerning the health status of the participants, including their metabolic status and body mass index.
After that, over the next 10 years, the participants were tested three times (in 1997-1999, 2002-2004 and 2007-2009) for cognitive abilities such as memory, argumentation ability and fluency of speech.
When analyzing the results, the body mass index in the range of 18.5-24.9 kg/m2 was considered normal, in the range of 25-29.9 – corresponding to overweight, and 30 and higher – indicating obesity.
Metabolic abnormalities were defined as the presence of two or more of the following risk factors:
- high blood pressure or the use of drugs to lower it;
- low levels of high-density lipoproteins or "good" cholesterol in the blood;
- high blood sugar levels or the use of drugs to reduce it;
- high levels of triglycerides (lipids) in the blood or the use of drugs for the treatment of diabetes.
At the initial stage of the study, 31% of the participants were classified as having metabolic abnormalities, 9% as obese and 38% as overweight. 350 out of 582 obese participants met the criteria for the presence of metabolic abnormalities.
The analysis of the data showed that during 10 years of observation, the decline of memory and thinking abilities in participants who simultaneously suffered from obesity and metabolic abnormalities occurred 22.5% faster than in participants with normal body weight who did not have metabolic abnormalities.
However, according to Archana Singh-Manoux, the lead author of the work, the results obtained do not support the idea of the reality of "metabolically healthy" obesity at all. The fact is that the cognitive abilities of obese participants without metabolic risk factors also deteriorated faster than the cognitive abilities of participants with normal weight and normal metabolic status. Although in this case the difference was not so catastrophic.
The authors believe that it is necessary to conduct further studies that would take into account the influence of genetic factors, and also take into account the duration of the period during which a person is obese and is at risk for metabolic factors. Moreover, it would be nice to subject participants to cognitive function testing throughout the entire period after coming of age. This would provide a more complete picture of the relationship between obesity and the dynamics of changes in abilities such as thinking, argumentation and memory.
Article by Archana Singh-Manoux et al. Obesity phenotypes in midlife and cognition in early old age: The Whitehall II cohort study is published in the journal Neurology.