Session Information
Date: Monday, October 22, 2018
Session Type: ACR Poster Session B
Session Time: 9:00AM-11:00AM
Background/Purpose:
Obesity is a major risk factor for knee osteoarthritis (OA), but the mechanisms by which obesity confers OA risk remains unclear. There is a recognized sex disparity in knee OA prevalence, and also a recognized distinct sex-specific distribution of fat depots especially after menopause in women. Visceral fat which accumulates after menopause is a major source of adipokines and other cytokines and its accumulation is associated with an increased heart disease risk. How these same metabolic products may affect OA risk is not clear. Given the recognized sex disparity in the occurrence of knee OA, whether body composition contributes to this disparity merits evaluation.
Methods:
We used data from participants free of OA at baseline in the Multicenter Osteoarthritis Study (MOST), a NIH-funded longitudinal cohort of persons with or at risk of knee OA. Incident radiographic OA (ROA) was defined as those who developed either radiographic knee OA (Kellgren-Lawrence (KL) ≥2) (irrespective of symptoms) or had a knee replacement (KR) during follow-up. We defined incident symptomatic OA (SOA) as those who developed radiographic knee OA (KL grade ≥2) with frequent knee pain, or a KR during follow-up over 5 years. Body composition was assessed at baseline using whole body dual-energy x-ray absorptiometry and analyzed using Hologic software to delineate visceral and subcutaneous fat, total fat mass, gynoid fat mass, android fat mass, and gynoid:android ratio. We evaluated the relation of sex-specific body composition parameters, categorized as quintiles, to risk of incident ROA and SOA using Cox proportional hazards model, adjusted for potential confounders.
Results:
We identified 514 participants with incident ROA (331 women and 183 men) and 433 with incident SOA (273 women and 160 men). The adjusted hazard ratio for risk of incident ROA in women compared with men was 1.24 (95%CI: 1.01-1.51) and was 1.14 (95%CI: 0.92-1.41) for incident SOA. Other measures of adiposity assessed were not associated with either OA outcome. Gynoid mass and gynoid-to-android ratio were associated with elevated risk of incident ROA and SOA, while total fat mass was only associated with incident ROA (Table).
Conclusion:
Our study indicates that differences in body composition related to total fat mass as well as the anatomic distribution of the fat mass, particularly a high gynoid-to-android ratio, were associated with elevated risk of OA and may explain the sex disparity in risk of OA. In contrast, the purported metabolic differences between visceral and subcutaneous fat did not impact OA risk.
|
Association between body composition and risk of incident OA |
||||
|
Radiographic OA |
Symptomatic OA |
|||
|
Q5 vs. Q1 |
P trend |
Q5 vs. Q1 |
P trend |
|
|
Total body fat mass, % |
1.01 (0.75-1.36) |
0.005 |
1.06 (0.77-1.46) |
0.23 |
|
Visceral fat, % |
1.24 (0.93-1.64) |
0.09 |
1.08 (0.80-1.44) |
0.73 |
|
Subcutaneous fat, % |
1.00 (0.80-1.24) |
0.02 |
1.08 (0.85-1.37) |
0.02 |
|
Ratio of Gynoid vs. Android fat mass |
1.67 (1.31-2.13) |
0.002 |
1.48 (1.13-1.92) |
0.002 |
|
Android fat, % |
0.60 (0.47-0.77) |
<0.001 |
0.68 (0.52-0.88) |
0.001 |
|
Gynoid fat,% |
1.69 (1.32-2.16) |
<0.001 |
1.47 (1.13-1.92) |
0.002 |
|
Q: Quintile HR and 95%CI were comparing Q5 vs. Q1 Multivariable model adjusted for age, sex, race, education level, physical activity, smoking, and BMI. |
||||
To cite this abstract in AMA style:
Li S, Neogi T, Misra D, Schwartz A, Nevitt MC, Lewis CE, Torner J, Felson DT. Can Body Composition Explain the Sex Disparity in Risk of Osteoarthritis? [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 9). https://acrabstracts.org/abstract/can-body-composition-explain-the-sex-disparity-in-risk-of-osteoarthritis/. Accessed .« Back to 2018 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/can-body-composition-explain-the-sex-disparity-in-risk-of-osteoarthritis/