RF18 | PSAT146 Bone Quality in Lean Adults with Metabolic Syndrome

Abstract

Purpose

Metabolic syndrome (MetS) comprises a constellation of risk factors for cardiovascular disease, which are thought to be derived from truncal obesity. Adipose tissue can have positive effects on bone density through mechanical stimulation on weight bearing sites and can have hormonal influences which affect bone cells, however in obesity this relationship is inversed as the deleterious effects of excess fat mass predominate. It is unclear how MetS and the regional distribution of fat relate with bone density and bone quality in lean individuals who do not benefit from increased weight bearing.

Methods

We performed a cross sectional analysis of adults who underwent bone density and body composition by dual energy x-ray absorptiometry (DXA) at a university health system bone clinic, and had laboratory and demographic data available in the electronic medical record. We included adults with BMI below 24.9 kg/m2 in the analysis. Individuals were classified as being metabolically unhealthy lean (MUL) when they fulfilled at least 2 of the following criteria: blood pressure > 130/85, triglyceride >150 mg/dL, HDL < 50 mg/dL for women and < 40 mg/dL for men, fasting plasma glucose >100mg/dL (or HbA1c >=5.7), and metabolically healthy lean (MHL) when they did not fit the criteria. Linear regression was used to evaluate the association of body composition fat parameters with trabecular bone score (TBS), and bone mineral density (BMD) at the total hip (TH).

Results

Among the 119 (100%) lean adults, 50 (42%) were classified as being MUL. Mean age was 62 ±14 years old and mean BMI was 22 ±1.9kg/m2. The population was mostly white 105 (88%) and 70 (41%) were Hispanics. Additionally, 43 subjects (40%) had a history of a previous fracture. Total body fat was similar between the two groups (mean,%) MHL 33.5, MUL 34.1 (p=0.32), as were age (mean, years) MHL 62.3 vs MUL 62.5 (p=0.48), BMI (mean, kg/m2) MHL 22.2, MUH 22.2 (p=0.49), TH BMD (mean, g/cm2) MHL 0.74, MUL 0.72 (p=0.140) and TBS (mean, unitless) MHL 1.34, MUL 1.33 (p=0.308). However, visceral adipose tissue area (VAT) (mean, cm2) was statistically significantly different between the groups (MHL 69.0, MUL 86.7, p=0.004). In linear regression analyses total body fat had negative association with TBS (B=-0.44, p<0.001) and TH BMD (B= -0.37, p<0.001) while VAT had negative association with TBS (B=-0.26, p=0.02) but not TH BMD (B=-0.17, p=0.08).

Conclusion

In our sample of older lean individuals body fat distribution varied by classification of metabolic health. Total body fat amount was associated with decreasing bone density and quality, while higher truncal fat as measured by VAT area was associated with decreasing bone quality. Our findings suggest that excess body fat may have deleterious effects on bone health even in lean individuals

Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m., Sunday, June 12, 2022 1:06 p.m. - 1:11 p.m.