158-OR: Relationship between Obesity, Sarcopenia, and Insulin Resistance in Older Adults

The prevalence of overweight/obesity is increasing in older adults worldwide. Ageing is generally associated with decline in muscle mass and strength (sarcopenia) and worsening insulin resistance (IR). We examined whether the coexistence of overweight/obesity and sarcopenia, termed sarcopenic obesity (SO), was associated with elevated IR, thus predisposing to increased cardiometabolic risk. After informed consent, we obtained the following anthropometric and laboratory data in 77 adults (43 females, 34 males, age range 65-80 years, mean age 71 years): body mass index (BMI, as a determinant of overweight/obesity); waist circumference (WC, abdominal obesity); thigh circumference and grip strength (measures of muscle mass and sarcopenia) ; fasting glucose and plasma insulin levels (for calculation of Homeostatic Model Assessment of Insulin Resistance, or HOMA-IR); and A1c.­­ 32 of the participants (42%) were normal weight, and 45 (58%) were overweight/obese. 15 individuals (19%) were classified as sarcopenic, and the prevalence was similar in normal weight vs. overweight/obese groups (19% vs. 20%). Selected mean parameters were: BMI 28.05, WC 113.8 cm, and HOMA-IR index 1.73 (normal <1). Analysis of the data showed a statistically significant positive association of HOMA-IR with BMI and WC (p<0.05), but not with sarcopenia. The WC correlated with glucose and insulin levels in both sexes (p<0.05), and with A1c in females only. Findings from our study thus far do not support a higher prevalence of sarcopenia in overweight/obese individuals than in those of normal weight. In both sexes, IR was significantly associated with overweight/obesity and central fat deposition, but not with sarcopenia. Interventions primarily targeting weight loss, with or without enhanced muscle conditioning, would be expected to be most effective in ameliorating IR and reducing cardiovascular and metabolic risk in older adults.