Nasal Morphology of Tibetan Populations: Sexual Dimorphism and Regional Variation

The human nose, crucial for respiratory function and facial aesthetics, exhibits diversity influenced by evolution, genetics, and environment. Tibetan populations, indigenous to the high-altitude Qinghai-Tibet Plateau, possess well-documented physiological adaptations to hypoxia. However, a comprehensive anthropometric analysis of their external nasal morphology, particularly regarding sexual dimorphism and regional variation, remains lacking.

We conducted a cross-sectional study of 508 healthy Tibetan adults (233 men, 275 women) aged 18 to 25 years from 4 prefectures. Standard anthropometric instruments were used to measure nasal dimensions. Derived indices included the nasal index (NI), nasal tip projection width index (NTPWI), and nasal tip projection length index (NTPLI). Data were analyzed using non-parametric tests, general linear models (GLM) adjusting for age, correlation analyses, and χ 2 tests.

Men had significantly greater nasal width (median: 3.80 vs. 3.39 cm), nasal depth, and NI (median: 76.92 vs. 61.51), whereas women had greater nasal height (median: 5.41 vs. 4.90 cm) (all P <0.01). Regional heterogeneity was more pronounced in men. Those from Shigatse had significantly greater nasal height and depth. In women, limited regional variation was observed, and nasal morphology was influenced by age. Nasal type distribution differed significantly by sex ( χ ²=306.803, P <0.001): mesorrhine was most common in men (65.7%), whereas leptorrhine predominated in women (58.2%).

Nasal morphology in young Tibetan adults exhibits significant sexual dimorphism and regional variation, particularly among men. These patterns likely reflect a complex interplay of high-altitude adaptation, developmental plasticity, and population history.