Genetic Variant in Leptin rs7799039 Is Associated with Total Body Mineral Estimates, but Not with Fat Mass, in Young Healthy Adults

Background/Objectives: The aim of this study was to investigate the association between the rs7799039 variant in the leptin (LEP) gene and specific parameters of body composition in young healthy Slovak adults using bioelectrical impedance analysis. Methods: We assessed 467 young adults aged 18 to 30 years with an average age of 22.55 ± 2.56 years. Genotyping of SNP LEP G-2548A (rs7799039) was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and body composition was assessed by bioelectrical impedance analysis (InBody 770). Results: Our results showed that the LEP rs7799039 variant was associated with total body mineral levels in women. The mean values of total body minerals (kg) were higher in LEP AA carriers than in carriers of the G allele (3.26 ± 0.52 kg compared to 3.09 ± 0.36 kg; p = 0.014). In addition, linear regression analysis showed statistically significant associations of the LEP gene rs7799039, vitamin D intake, body mass index (BMI) and height on total body mineral content in women (p < 0.05). The presence of the LEP AA genotype, reported vitamin D intake and higher BMI and height values were positively associated with higher total body mineral content. No association was found between the LEP rs7799039 variant and BMI, fat mass (FM) or FM distribution across body segments. Conclusions: Our data suggest that the rs7799039 variant in the LEP gene may be associated with small differences in total body mineral content in young adult women. These findings should be interpreted as exploratory associations, rather than evidence of biological specificity or an independent genetic effect.