Socioeconomic Status and CT-Derived Muscle Quantity and Quality: Divergent Associations
2Samueli Institute, Samueli Integrative Cancer Pioneering Institute, Israel
3Department of Oncology, Samueli Integrative Cancer Pioneering Institute, Israel
Purpose: To examine how CT-derived muscle and fat parameters vary with socioeconomic status (SES) in an Israeli adult cohort, and whether associations differ by sex.
Methods: We analyzed 9,625 adults (4,792 women, 4,833 men; mean age 54 years): 9,089 patients with SES data from the general-population CompoCT cohort, plus 536 patients added to fill sparse sex, age and SES strata. SES was assigned from residential address by locality-level clustering and grouped into five tiers. CompoCT, an automated algorithm, measured skeletal muscle index (SMI), muscle density (SMD), and visceral, subcutaneous and intermuscular fat indices at L3. Linear regression with age and age², run separately by sex, compared each tier with Medium SES. Contrast phase was added as a covariate in sensitivity analyses.
Results: Mean age rose from 44 years in Very Low to 58 in Very High SES, so all models were age-adjusted. SMD was higher at higher SES in both sexes. In women, differences from Medium were −3.07 HU (Very Low), −1.69 (Low), +1.44 (High) and +1.33 (Very High; all p<0.001); in men, only High (+0.69, p=0.009) and Very High (+1.40, p<0.001) differed. SMI showed the opposite direction: it was higher in Very Low SES in women (+2.59, p<0.001) and men (+1.35, p=0.018). Visceral fat index rose steadily toward lower SES in women (+10.15 in Very Low to −6.48 in Very High, all p<0.001) but not in men (all p>0.5; SES×sex interaction p<0.0001). Adjustment for contrast phase left the findings essentially unchanged, and a three-tier analysis was consistent.
Conclusions: Lower SES was associated with lower muscle quality despite higher muscle quantity, and with more visceral fat in women only. Muscle quantity alone may therefore not reflect SES-related differences in muscle health.