Older adults who are "skinny fat" -- the combination of low muscle mass and strength in the context of high fat mass -- may be at risk of developing decline in cognitive performance, a study contends.

"Skinny fat" is the colloquial term for the medical condition sarcopenic obesity, which depicts people who are thin, but with high levels of body fat and visceral fat.

Skinny fat people tend to have a normal weight and BMI, but not enough muscle and thus at high risk of health complications, such as Type-2 diabetes and heart diseases.

The results, published in the journal Clinical Interventions in Aging, demonstrated that sarcopenic obesity or being "skinny fat" was associated with the lowest performance on global cognition, followed by sarcopenia alone and then obesity alone. 

But, obesity and sarcopenia together, were associated with lower executive function such as working memory, mental flexibility, self-control and orientation, the researchers said. 

"Sarcopenia has been linked to global cognitive impairment and dysfunction in specific cognitive skills including memory, speed, and executive functions," said James E. Galvin, neuroscientist and Professor at the Florida Atlantic University (FAU) in the US.

For the study, the team used data from a series of ageing and memory studies including 353 participants, with an average age of 69 years. 

They found consistent evidence to link sarcopenic obesity to poor global cognitive performance in the study subjects. 

Executive function is reduced in obese older adults, and improvement in muscular function has been linked to enhancement of executive function in senior adults.

Changes in body composition including a shift toward higher fat mass and decreased lean muscle mass represent a significant public health concern among older adults as it may lead to various negative health outcomes including cardiovascular and neurodegenerative diseases.

"Sarcopenia either alone or in the presence of obesity, can be used in clinical practice to estimate potential risk of cognitive impairment," said Magdalena I. Tolea, a research assistant professor at the FAU.