Associations of sarcopenic obesity with the metabolic syndrome and insulin resistance over five years in community-dwelling older men: The concord health and ageing in men project.

Abstract

Introduction: Sarcopenia and obesity may independently contribute to risk of metabolic syndrome (MetS) and insulin resistance in older age, but it is unclear whether sarcopenic obesity has synergistic effects. The aim of the present study was to determine cross sectional and 5-year longitudinal associations between sarcopenic obesity, MetS and insulin resistance in community-dwelling older men. Method(s): 1,057 community-dwelling men aged >=70 years that had measures of appendicular lean mass (ALM) and body fat percentage assessed by whole-body dual-energy X-ray absorptiometry (DXA), completed grip strength assessments, and had MetS measures at baseline. Sarcopenia was defined as low ALM relative to BMI and/or low grip strength (Foundations for the National Institutes of Health definition). Obesity was defined body fat percentage >=30%. MetS components (waist circumference, systolic (SBP) and diastolic blood pressure (DBP), fasting glucose, triglycerides, and high-density lipoprotein [HDL] cholesterol) were assessed at baseline and 5-years later. Fasting insulin and Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) were assessed at 5 years only. Result(s): 394 (37%) men were non-sarcopenic non-obese, 125 (12%) were non-sarcopenic obese, 197 (19%) were sarcopenic non-obese, and 341 (32%) were classified as sarcopenic obese. The overall prevalence of MetS at baseline was 38%, with sarcopenic obese (odds ratio, 95% CI: 5.1, 3.6- 7.3) non-sarcopenic obese (5.2, 3.3-8.2) and sarcopenic non-obese (2.0, 1.3-3.0) all demonstrating higher likelihood for MetS than non-sarcopenic non-obese men after multivariable adjustment. However, there were no differences in likelihood of incident MetS, or changes in components of MetS over five years for any category. Amongst components of body composition, change in body fat (per kg) over five years was a predictor of incident MetS (1.2, 1.1-1.3) and of deleterious changes in MetS components (DBP, glucose, HDL, triglycerides; all P < 0.05). Compared with non-sarcopenic non-obese men, estimated marginal means for HOMA IR at five years were significantly higher in sarcopenic obese (1.1, 0.8-1.4 vs 0.7, 0.4-1.0; P < 0.001), but not other groups. Conclusion(s): Sarcopenic obese older men have increased likelihood of prevalent MetS and its components, and increased insulin resistance, compared with older counterparts with healthy body habitus. However, increases in body fat, rather than sarcopenia-associated decreases in low lean mass or hand grip strength, appear to be the most important predictor of incident MetS.