Age modifies the association between body composition and S1P levels in the study of health in pomerania

Abstract To investigate whether age modifies the associations between body composition markers and sphingosine-1-phosphate (S1P) levels in the Study of Health in Pomerania (SHIP) cohort. Among 4,080 participants (2,275 women, 51.4%), we examined age-specific associations of anthropometric (BMI, waist circumference, waist-to-height ratio) and MRI-derived (visceral and subcutaneous adipose tissue, liver fat) body-composition markers with S1P. Sex-stratified linear regression models, including interaction terms with age, were used. Overall, no significant body composition–S1P associations were found without accounting for age interactions. However, age significantly modified these associations: all body composition markers were positively associated with S1P at younger ages (20–30 years), weakened, became non-significant around midlife (35–50 years), and reversed in older adults (≥ 55 years). For example, at younger ages, BMI was positively associated with S1P—men: β = 0.029 (95% CI: 0.008 to 0.050); women: β = 0.025 (95% CI: 0.008 to 0.042), but negatively associated at older ages—men: β = −0.037 (95% CI: −0.056 to − 0.018); women: β = −0.022 (95% CI: −0.037 to − 0.006). Similar age-dependent patterns were observed for others markers. Our findings highlight that age substantially modifies the associations between body composition markers and S1P, underlining the importance of considering age in understanding metabolic risk.