With an increase in both T2D and NAFLD, plus an aging population, early identification of mild cognitive impairment could be critical.

“Since changes in fine motor performance may serve as an early warning sign for reduced cognitive function—and those with T2D and nonalcoholic fatty liver disease (NAFLD) are at increased risk for mild cognitive impairment—it is imperative to understand the association between the two conditions,” explains Zobair M. Younossi, MD, MPH.

For a study published in Annals of Medicine, Dr. Younossi, Ali A. Weinstein, MD, and colleagues sought to assess the correlation between fine motor performance and physical activity in people at risk for cognitive impairment, specifically those with diabetes, NAFLD, or both. The study enrolled 93 individuals aged 25 to 69 with and without diabetes and NAFLD. The researchers measured fine motor performance using the Grooved Pegboard Test and the motor speed score from the Delis-Kaplan Executive Function System (D-KEFS) Trail Making Test, and levels of physical activity using the Human Activity Profile (HAP). “Our study was the first to examine the relationship between physical activity levels—a modifiable factor—and fine motor performance in these at-risk populations,” Dr. Younossi says.

‘Physical Activity Is a Modifiable Factor’

The study team observed that individuals with both T2D and NAFLD have lower levels of physical activity and slower fine motor performance than those with NAFLD alone. Among those with NAFLD alone, a statistically significant correlation was found between physical activity and motor speed (r=0.436, P<.05), which stayed statistically significant after controlling for BMI (r=0.385; P<.05).

The researchers agree that “Physical activity is a modifiable factor that might help to protect fine motor performance. Therefore, individuals with T2D should be identified and encouraged to exercise, to help prevent functional deficits and perhaps to avert the development of NAFLD, if it is not already present. We know that exercise can mobilize fat from the liver, so encouraging exercise can offer benefits on multiple fronts: physical function, diagnostic, and cognitive function preservation.”

Preservation of Cognitive Function Can Be a Powerful Motivation

Drs. Younossi, Weinstein,  and colleagues frequently observe that associations between T2D and NAFLD in individuals are driven by obesity. “Therefore, we wanted to investigate the relationships of interest while controlling for BMI, a marker for obesity,” Dr. Younossi says. “BMI does have an impact on the relationship between physical and fine motor performance. The main takeaway from this is that individuals with NAFLD alone have the strongest relationship between physical activity and fine motor performance, independent of BMI. Individuals with T2D may have other metabolic and mechanical factors that impact this relationship that people with NAFLD alone do not have. This suggests early intervention for those with NAFLD alone, for the prevention of T2D.” (Table)

Assessment of physical activity level is key for both T2D and NAFLD, the study team notes. “The impact of physical activity can be profound on so many facets of an individual’s functional and health status,” she says. “It is essential for prevention of future morbidity, particularly for those with T2D and/or NAFLD. The potential to retain cognitive function can be a powerful motivating tool for increasing physical activity.”

With the increasing prevalence of both T2D and NAFLD, plus the aging of the population, early identification of mild cognitive impairment could be a critical breakthrough. “Fine motor performance may be an important early marker of mild cognitive impairment,” Dr. Younossi says. “Therefore, identification of the mechanistic factors that connect fine motor performance and physical activity, particularly in at-risk populations, needs to be the focus of future research.”