Sarcopenic Obesity Is a Risk Factor for Metabolic Syndrome in Young Adult Men, but Not Women

Presentation Number: SAT 505
Date of Presentation: April 1st, 2017

Melanie Schorr*1, Aaron Leong1, Bianca Porneala2, Laura E. Dichtel1, Miriam A. Bredella1 and Karen K. Miller1
1Massachusetts General Hospital/Harvard Medical School, Boston, MA, 2Massachusetts General Hospital, Boston, MA

Abstract

Sarcopenic obesity, reduced skeletal muscle mass in the setting of obesity, is an important cardiometabolic risk factor in the elderly. Skeletal muscle mass is generally greater in young overweight/obese than lean adults, in part due to higher load (weight). It is unknown whether relatively lower skeletal muscle mass for BMI in young adults, i.e. relative sarcopenia, contributes to cardiometabolic risk. We hypothesized that relative sarcopenia is associated with insulin resistance (IR) and the presence of metabolic syndrome (MetS) and type 2 diabetes mellitus (DM) in young overweight/obese adults.

We studied 1507 US adults (BMI ≥ 25kg/m2, 20-49 y) in NHANES 2005-2006. Exclusion criteria included pregnancy, menopause and glucocorticoid use. Skeletal muscle mass of both arms and legs [appendicular lean mass (ALM)] and total body fat mass (FM) were measured by DXA. Relative sarcopenia was defined as low ALM/BMI. MetS was defined per NCEP ATPIII criteria. IR was assessed by HOMA-IR. Using sex-stratified regression models adjusted for age, race and physical activity (PA), we tested whether relative sarcopenia was associated with IR or the presence of MetS or DM. Effect estimates were reported per standard deviation (SD) change in ALM or ALM/BMI.

Non-Hispanic Blacks had higher, and Hispanics lower, ALM and ALM/BMI than non-Hispanic Whites. Age was a negative, and PA a positive, determinant of ALM and ALM/BMI. Oral contraceptive use was not associated with ALM or ALM/BMI. MetS was present in 21% of participants, and DM in 7%. Higher ALM was associated with MetS (in both sexes) (men: OR 2.33 (1.73-3.14), p<0.0001; women: OR 1.83 (1.34-2.50), p=0.0001). In contrast, relative sarcopenia (lower ALM/BMI) was associated with MetS (in men only) (men: OR 0.60 (0.44-0.83), p=0.002; women: OR 0.87 (0.64-1.19), p=0.38). When relative sarcopenia was defined as lower ALM/FM, it was associated with MetS (in both sexes) (men: OR 0.36 (0.28-0.48), p<0.0001; women: OR 0.71 (0.50-1.0), p=0.05). In participants without DM, higher ALM was associated with higher IR (in both sexes) (men: β=1.19, p<0.0001; women: β=0.72, p<0.0001), whereas lower ALM/BMI was associated with higher IR (in men only) (men: β=-1.04, p<0.0001; women: β=-0.25, p=0.09). Similarly, higher ALM was associated with DM (in both sexes) (men: OR 1.71 (1.16-2.51), p=0.006; women: OR 1.96 (1.39-2.75), p=0.0001), whereas lower ALM/BMI was associated with DM (in men only) (men: OR 0.36 (0.20-0.67), p=0.001; women: OR 0.90 (0.57-1.43), p=0.66). 

In conclusion, relative sarcopenia is a risk factor for MetS, IR and DM in young overweight/obese adults. Examining skeletal muscle mass without accounting for BMI obscures the relationship between reduced muscle mass and cardiometabolic risk factors because higher BMI is associated with greater muscle mass. Determining whether sex differences exist and if so, why, merits further study.

 

Nothing to Disclose: MS, AL, BP, LED, MAB, KKM