DIFFERENTIAL ASSOCIATIONS BETWEEN PHYSICAL ACTIVITY AND GLYCEMIC CONTROL ACROSS BODY MASS INDEX IN TYPE 2 DIABETES: A...

Glycated hemoglobin (HbA1c) is the primary biomarker for assessing long-term glycemic control in type 2 diabetes (T2D). However, its wait time of 2-3 months, affects the timely intervention for the identification of acute metabolic enhancements resulting from lifestyle modifications. On the other hand, fructosamine reflects the glycemic regulation for over a period of 2-3 weeks and may provide supplementary short-term monitoring functions. Nevertheless, there is scant information comparing these markers across varying levels of physical activity and body mass index (BMI) strata in people with type 2 diabetes (T2D).

To assess HbA1c and fructosamine as indicators of glycemic control in physically active and sedentary people with Type 2 Diabetes, and to investigate if BMI, sex, and glucose-lowering drugs influence the association between physical activity and these glycemic markers.

This cross-sectional study was conducted at Thumbay Labs in the United Arab Emirates from January to October 2025, included 185 persons with Type 2 Diabetes (T2D), classified as physically active (n=98, engaging in ≥150 minutes of activity per week for over 3 months) or sedentary (n=87). HbA1c and fructosamine were assessed utilizing standardized laboratory techniques. Multivariable linear regression models evaluated the relationships between physical activity and glycemic indicators, controlling for age, sex, BMI, and primary glucose-lowering drug classes, while explicitly testing for interactions between Activity and BMI, as well as Activity and Sex.

Physically active participants exhibited lower HbA1c (6.84% vs. 8.07%, p<0.0001) and fructosamine levels (301.0 vs. 362.0 µmol/L, p=0.0001) compared to sedentary individuals. A significant Activity × BMI interaction for HbA1c (β=0.156, p=0.0002) was found, indicating decreased glycemic benefits of physical activity with higher BMI, persisting after controlling for diabetes medications. A similar but weaker effect for fructosamine (β=7.481, p=0.0019) was noted. No notable differences were observed between sexes regarding these markers when BMI was considered.

Physical activity is associated with glycemic control, which is supported by HbA1c and fructosamine levels, even though obesity declines this effect, especially in long-term glycemic memory (HbA1c). Individuals who fall under the T2D and increased BMI category need stronger lifestyle interventions for similar glycemic benefits as those with lower BMI. HbA1c is a more reliable marker for activity-related metabolic benefits in stable T2D, while fructosamine is a useful short-term indicator but not interchangeable.