Dyslipidemia is associated with abdominal fat depots but not with bone mineral density and muscle fat infiltration

Dyslipidemia (DLP) is linked to adverse abdominal fat distribution; however, its relationship with bone mineral density (BMD) and muscle fat infiltration (MFI) remains unclear. This study aimed to assess, using quantitative computed tomography (QCT), whether DLP is associated with abdominal fat depots, and if it independently correlates with BMD or MFI. This cross-sectional study included participants aged ≥ 40 years from a health check-up cohort. Demographic data and fasting blood lipid measurements were collected for analysis. QCT imaging at the L2 vertebral level was employed to assess lumbar BMD at L1-L2, subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), liver fat fraction (LFF), and paravertebral extensor muscle fat fraction (MFF). Participants were categorized into DLP and non-DLP groups based on lipid profiles or the use of lipid-lowering medication. Sex-specific analyses were conducted in both male and female participants, with adjustment for age, body mass index (BMI), and waist circumference (WC); menstrual status was additionally included as a covariate in analyses of female participants. The study included 2,115 participants: 1,426 males (53.3 ± 2.9 years; 48.7% DLP) and 689 females (48.9 ± 2.5 years; 29.0% DLP). Participants in the DLP group were younger on average (males: 52.6 ± 2.4 vs. 53.9 ± 3.1 years; females: 47.8 ± 1.9 vs. 49.4 ± 2.6 years), and had higher weight, BMI, and WC. However, increases in weight and WC were statistically significant only in males. The proportion of postmenopausal women was higher in the non-DLP group (32.5%). Age was the main factor influencing BMD, MFF, and VAT area in males, and BMD and LFF in females. Unadjusted comparisons revealed higher MFF in males and greater BMD, LFF, and SAT areas in females with DLP. After adjusting for confounders, especially age, differences in BMD and MFF were no longer significant in either sex. In fully adjusted models, no significant differences in body composition parameters were observed in males. In females, however, the DLP group had significantly higher LFF (P < 0.001), SAT (P = 0.012), and VAT areas (P = 0.022). This study confirms a sex-specific association between DLP and abdominal fat depots, with females showing higher liver fat and larger subcutaneous and visceral adipose areas. Critically, it demonstrates that DLP is not independently associated with BMD or MFI, as these parameters were primarily influenced by age. This dissociation underscores distinct pathophysiological pathways connecting DLP to different body composition compartments.