AMERICAN JOURNAL OF HUMAN BIOLOGY, vol.37, no.6, 2025 (SCI-Expanded)
Background: The distal limbs (radius/ulna and tibia/fibula) are known to exhibit greater plasticity to external factors than the proximal limbs. However, the specific ways in which various factors influence the distal limbs, and the methods to assess the degree of their impact, remain insufficiently explored. Aim: This study aimed to investigate how the body parts of adults who grew up under varying social, economic conditions, and physical stress adapt to these factors. Additionally, it sought to determine the role of the distal limbs in body proportions under different environmental conditions. Subjects and Methods: An anthropometric survey was conducted in Samsun, Turkey, involving 623 individuals (304 females and 319 males) aged 20-45 years. To examine the effects of socioeconomic structure and physical stress, the sample was categorized into three groups: an upper socioeconomic status group (n:202), a lower socioeconomic non-working group (n:210) and a lower socioeconomic heavy working group (n:211). One-way ANOVA was conducted to analyze intergroup differences, while Model 4 of the SPSS Macro Mediation Analysis (Bootstrap Method) was used to assess the contribution of distal limb measurements to upper and lower body segments. Results: Socioeconomic differences in height were significant (p < 0.05). Tibia length was greater in the high socioeconomic group but shorter in the heavy working and non-heavy working groups. The contribution of forearm length showed more significant variation between the different groups, particularly in the heavy working group. Conclusion: The study found that socioeconomic factors and physical stress influence distal limb development. While stress suppresses tibial growth, it promotes forearm length, emphasizing the role of forearm length in body proportions.