Thresholds of fat mass index percentiles and their association with cardiovascular risk in adolescents: Results from the EVA4YOU study

BACKGROUND AND AIMS: The presence of cardiovascular risk factors (CV-RFs) like obesity in adolescents leads to accelerated vascular ageing and a higher risk of cardiovascular disease (CVD) later in life. While Body Mass Index (BMI) is commonly used to assess adiposity, it lacks the ability to differentiate fat from lean mass. The Fat Mass Index (FMI) provides a more specific measure of adiposity and may better reflect cardiovascular risk. This study investigates the association between FMI percentiles and CV-RFs in adolescents, aiming to identify potential FMI thresholds indicative of elevated vascular risk. METHODS AND RESULTS: This analysis is part of the EVA4YOU study involving 1517 adolescents (14-19 years) from Tyrol, Austria. Triglycerides (TG), HDL cholesterol (HDL-C), LDL cholesterol (LDL-C), blood pressure (BP), and liver fat were classified as acceptable versus borderline or high. Diagnostic odds ratios (DORs) and prevalence of CV-RFs were assessed across FMI percentiles. Only 27.9 % of participants had no CV-RFs, while 12.4 % had ≥3. With rising FMI percentiles, CV-RFs became increasingly prevalent: only 9.5 % of adolescents above the 95th percentile had no CV-RFs, while 44.6 % had ≥3. DORs for high BP, TG, liver fat, and low HDL-C consistently increased with higher FMI percentiles. CONCLUSION: The prevalence of CV-RFs in adolescents is high and constantly increases with increasing FMI percentiles, showing a peak at the 95th percentile. However, since even lower FMI Percentiles are associated with increased odds of elevated CV-RFs, further diagnostics and preventive measures should not be based solely on a single percentile threshold. CLINICAL TRIAL REGISTRY: NCT04598685.