Earlier study has connected obesity with enhanced risk of dementia. But a new research – considered the biggest ever to evaluate the link between body mass index and dementia risk – recommends obesity could basically be a protective factor towards the condition, while individuals who are underweight may be at enhanced risk.
Research author Prof. Stuart Pocock, and colleagues presented their results in The Lancet Diabetes & Endocrinology.
Dementia is a name used to explain a number of disorders associated with a decrease in memory and thinking skills. Alzheimer’s disease is the very common type of dementia, accounting for about 60-80% of cases in the US.
Some risk aspects for dementia are well founded. It is well-known that a person’s possibility of the problem increases with age, for example and individuals with a family history of the problem are more probably to develop it themselves.
Progressively, scientists are looking at how an person’s weight influences their possibility of dementia, but outcomes have been conflicting. In 2011, for instance, a study presented in the journal Neurology connected midlife obesity to enhanced risk of dementia later in life.
In February 2015, however, other study reported that while obesity may lead to a greater dementia risk for young and middle-aged adults, it may protect towards the condition for elderly people.
In this recent research, Pocock and colleagues examined the medical information of nearly 2 million individuals in the UK to be able to gain a better understanding of how obesity impacts dementia risk.
Higher dementia risk for underweight middle-aged people
Seeking at a period of 20 years, the scientists took their data from the Clinical Practice Research Datalink (CPRD) – a big database that keeps the medical records of roughly 9% of the UK population.
The adults involved in the research were an average age of 55 at baseline and had a median body mass index (BMI) of 26.5 kg/m2, which comes into the overweight category.
Over an average follow-up period of 9 years, 45,507 people were clinically diagnosed with dementia.
The investigators identified that, in comparison with adults who had a healthy BMI (between 20-25 kg/m2), those who were underweight – described in this research as a BMI less than 20 kg/m2 – while in middle age were 34% more probably to be identified with dementia. This enhanced risk stayed for 15 years after adults’ underweight status was recorded.
The team notices that individuals with a BMI of less than 18.5 kg/m2 are generally considered as underweight, but the threshold was increased in this research to enable comparisons with earlier studies, which have described a BMI of less than 20 kg/m2 as underweight.
The investigators also identified that middle-aged adults’ risk of dementia steadily decreased as their BMI enhanced. In comparison with adults who had a healthy BMI, those who were seriously obese (BMI greater than 40 kg/m2) were 29% less probably to develop dementia.
The team states that their outcomes remained even after accounting for things connected with enhanced dementia risk, such as smoking and alcohol intake. In addition, the outcomes were not impacted by adults’ age at dementia diagnosis or the decade in which they were born, with respect to the investigators.
Outcomes may result in new therapies for dementia
Prof. Pocock states that the team’s results recommend that physicians, public health researchers and policymakers have to re-assess the best ways to recognize which individuals are at great risk of dementia.
“We also require to focus on the causes and public health effects of the link between underweight and enhanced dementia risk which our study has established,” he adds.
“Even so, our outcomes also open up an intriguing new path in the search for protective aspects for dementia – if we can understand why individuals with a high BMI have a decreased risk of dementia, it’s feasible that further down the line, scientists might be capable to use these insights to develop new therapies for dementia.”
Lead study author Dr. Nawab Qizilbash, says additional research is warranted to understand the mechanisms that lead the connection between high BMI and decreased dementia risk.
“If enhanced weight in midlife is protective against dementia, the causes for this inverse connection are not clear at present,” he adds. “Numerous issues associated to diet, exercise, frailty, genetic aspects and weight change could play a role.