Peng Nanhui, Li Jia, Liu Baifang, Yan Xu, Ouzhu Nima
Exercise and Virtual Simulation Laboratories, College of Physical Education, Southwest University, Chongqing, China.
Institute for Health and Sport, Victoria University, Melbourne, Australia.
PLoS One. 2025 Aug 1;20(8):e0328992. doi: 10.1371/journal.pone.0328992. eCollection 2025.
While high altitude has been associated with reduced muscle mass, its effects on fat mass remain controversial, with studies reporting both fat accumulation and loss. Normal weight obesity (NWO), characterized by normal body mass index (BMI) but excessive body fat, is an emerging metabolic health concern. This study aimed to investigate the prevalence of NWO among young adults in a high-altitude region, while also analyzing body composition differences between genders, as well as native versus migrant populations.
In this cross-sectional study, 1,313 university students (mean age: 19.6 ± 1.6 years; 719 females and 594 males; all enrolled in undergraduate studies) from Lhasa, Tibet (altitude: 3,650m), who voluntarily participated in body composition measurements during the university's annual physical fitness assessments. The participants were from multiple academic departments. They underwent anthropometric and body composition assessments, including body fat percentage (BF%), fat-free mass (FFM), skeletal muscle mass (SMM), and waist-to-hip ratio (WHR). Participants were stratified by BMI and BF% to determine NWO prevalence, with subgroup analyses for gender and residential background.
BF% trends varied by gender; female students showed a linear increase with BMI, while male students exhibited a phased pattern with two turning points at BMI = 19.6 and 26.5. The overall prevalence of NWO among high-altitude university students was 22.2%, accounting for 57% of individuals with excessive body fat. Females were disproportionately affected (27.7% vs.16.7% in males). Both females and males with NWO had significantly lower FFM and SMM than their non-NWO counterparts (P < 0.001). A subset analysis of 389 individuals revealed that NWO incidence was significantly lower among high-altitude native females and males compared with their migrant counterparts. Among those with NWO, migrant females had a higher BF% (P = 0.02), whereas native males exhibited a higher WHR (P = 0.009).
NWO prevalence among young adults in a high-altitude region was comparable to lowland populations, with notable gender disparities. NWO was associated with reduced muscle mass, suggesting elevated metabolic health risks. The lower NWO prevalence among native high-altitude residents suggests potential protective effects associated with chronic hypoxia adaptation. These findings underscore the need for further research to elucidate the complex relationship between chronic hypoxia, body composition, and metabolic health in high-altitude populations. Such insights are crucial for developing targeted interventions addressing normal weight obesity.
虽然高海拔与肌肉量减少有关，但其对脂肪量的影响仍存在争议，一些研究报告了脂肪的积累和减少。正常体重肥胖（NWO）以正常体重指数（BMI）但身体脂肪过多为特征，是一个新出现的代谢健康问题。本研究旨在调查高海拔地区年轻成年人中NWO的患病率，同时分析性别之间以及本地人与移民人群之间的身体成分差异。
在这项横断面研究中，来自西藏拉萨（海拔3650米）的1313名大学生（平均年龄：19.6±1.6岁；719名女性和594名男性；均为本科生）自愿参加了学校年度体能评估期间的身体成分测量。参与者来自多个学术部门。他们接受了人体测量和身体成分评估，包括体脂百分比（BF%）、去脂体重（FFM）、骨骼肌质量（SMM）和腰臀比（WHR）。参与者按BMI和BF%分层以确定NWO患病率，并按性别和居住背景进行亚组分析。
BF%趋势因性别而异；女学生的BF%随BMI呈线性增加，而男学生呈现出分阶段模式，在BMI = 19.6和26.5处有两个转折点。高海拔地区大学生中NWO的总体患病率为22.2%，占身体脂肪过多个体的57%。女性受影响的比例过高（女性为27.7%，男性为16.7%）。患有NWO的女性和男性的FFM和SMM均显著低于非NWO的同龄人（P < 0.001）。对389人的子集分析显示，高海拔本地女性和男性的NWO发病率显著低于移民同龄人。在患有NWO的人群中，移民女性的BF%更高（P = 0.02），而本地男性的WHR更高（P = 0.009）。
高海拔地区年轻成年人中NWO的患病率与低地人群相当，存在显著的性别差异。NWO与肌肉量减少有关，表明代谢健康风险升高。高海拔本地居民中较低的NWO患病率表明与慢性缺氧适应相关的潜在保护作用。这些发现强调需要进一步研究以阐明高海拔人群中慢性缺氧、身体成分和代谢健康之间的复杂关系。这些见解对于制定针对正常体重肥胖的有针对性干预措施至关重要。
