By comparing data from almost 4,000 people, researchers identified that women are more susceptible than men to having more accelerated cognitive decline when blood glucose is not controlled.
In the work, curiously, memory loss was not identified among the cognitive problems, but mainly impairments in so-called executive functions – cognitive processes that involve controlling emotions, planning and carrying out actions and thoughts.
“Cognitive decline can occur with aging as a result of changes in the central nervous system. But what we saw in the study is that it occurred more quickly in women with diabetes and without adequate blood glucose control. Among men, no association was observed between diabetes and cognitive decline, whether with controlled glycemia or not. This shows the importance of deepening the understanding of how diseases occur in different ways between men and women and also, in the case of diabetes, the importance of adequate glycemic control”, Tiago da Silva Alexandre, professor in the Department of Gerontology at the Federal University of São Carlos (UFSCar) and advisor of the study, which was supported by FAPESP.
Published in the magazine Journals of Gerontology Series Athe study analyzed data from 3,984 participants over the age of 50 – 1,752 men and 2,232 women – for eight years. Participants are part of the ELSA Study (English acronym for English Longitudinal Study of Aging).
ELSA collects multidisciplinary data from a representative sample of the British population and is led by University College London – UCL (United Kingdom). The research on diabetes and impaired cognitive function was developed by researcher Natália Cochar Soares, a FAPESP scholarship holder, with the participation of co-authors from the University of São Paulo (USP) and UCL, in addition to UFSCar.
Diabetes is a disease with a strong impact on different organs, such as the kidneys, eyes, muscles, nerves and brain. This is because excess glucose in the blood causes various injuries to blood vessels, leading to an increase in inflammatory factors that can lead to gangrene, amputation, kidney failure, vision impairment and an increased risk of cardiovascular diseases.
In the case of the brain, inflammatory factors can lead to atrophy, a reduction in the number of neurons and changes in areas such as the hippocampus and prefrontal cortex, related to cognitive domains such as executive functions.
“Cognitive decline in these cases, therefore, is associated with cerebral small vessel disease. A possible explanation for the acceleration observed only in women without adequate glycemic control is hormonal factors. Estrogen is a known neuroprotector, but during menopause there is a reduction in this hormone in women, which can lead to greater vulnerability”, explains Soares.
“But there are also social factors. In the study, British elderly people had more education than women. It is known that education contributes to greater cognitive reserve, a mechanism possibly capable of compensating for the effects of a brain injury. Regardless of the reason behind this difference between men and women, the results draw attention to the need for adequate glycemic control”, adds the researcher.
Soares explains that there are six cognitive domains: executive function, language, attention, memory, perceptual motor and social cognition. In the study, researchers observed declines in global cognition and executive function, but did not find memory impairments.
“This was a little surprising, as generally the onset of cognitive decline tends to occur in memory and this was not what happened in the cases studied. There is a physiological explanation for this: the brain structures that will be compromised due to the inflammatory vascular changes caused by diabetes are those responsible for executive function and not memory. Diabetes affects brain areas more associated with executive functions, such as the prefrontal cortex”, says Soares.
In the study, glycemic control was assessed through the levels of glycated hemoglobin (HbA1c) in the blood – a parameter that reflects the amount of circulating sugar. In individuals with diabetes, the glycemic target is reached when HbA1c levels are between 6.5% and 7%, which characterizes adequate glycemic control. HbA1c levels above 7% correspond to worse glycemic control.
One previous studycarried out by the same group of researchers, showed that inadequate glycemic control leads to a greater decline in walking speed in elderly people.
“With these two studies we show the importance of good glycemic control for the cognition and mobility of elderly people. This shows the need for stricter glycemic control, regardless of the condition. We argue that the HbA1c value needs to be maintained between 6.5%, which is the normality cutoff point, and 7%, which is good blood glucose control. Continuous lack of blood glucose control can generate long-term damage to blood vessels that result in a series of problems in various organs, including cognition and mobility”, says Alexandre.
The researcher emphasizes that the cognitive impairment caused by the lack of adequate blood glucose control in Brazilian women may be even greater than that observed in the study.
“The population study was carried out with British elderly people, but I believe that in Brazil the data could be a little worse than what was observed in the United Kingdom due to the issue of education. The average level of education of elderly people in Brazil is much lower than in the United Kingdom and this means that the cognitive reserve, which would be a protective effect against vascular lesions in the brain, is also lower”, says Alexandre to Agência FAPESP.
This content was originally published in Women with uncontrolled blood sugar have a higher risk of cognitive decline on the CNN Brasil website.
Source: CNN Brasil
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