Novak Jan M, Bruzek Jaroslav, Zamrazilova Hana, Vankova Marketa, Hill Martin, Sedlak Petr
Department of Anthropology and Human Genetics, Faculty of Science, Charles University, Prague, Czech Republic.
Institute of Endocrinology, Prague, Czech Republic.
PeerJ. 2020 May 11;8:e8951. doi: 10.7717/peerj.8951. eCollection 2020.
The effect of fat tissue on a developing individual is fundamentally different from the effect on an adult. Several changes caused by obesity during sexual maturation have an irreversible and severe negative effect (lower fertility, reduced final height, type 2 diabetes mellitus) even for those who have subsequently lost weight. Our study was focused on monitoring the skeletal structure substantially influenced by sex hormones-the pelvis. The adult pelvis is strongly sexually dimorphic, which is not the case for the juvenile pelvis; skeletal differences between sexes are not so prominent and start to manifest with the onset of puberty. Evidence from animal models and case studies of treatment of gender dysphoria suggests that estrogens have a stimulatory effect on the growth plates present on the pelvis, leading to morphological change. Male obesity, especially in puberty, is connected with hypogonadism, manifesting in low levels of testosterone, and high levels of estrogens. The goal of our study was to evaluate the influence of obesity during adolescence on the morphology of the adult pelvis in the context of androgen and estrogen status.
Our sample consists of 238 individuals (144 females, 94 males) observed after an 8 year follow-up (mean age during enrollment 15.2 years, follow-up 23.3 years). Anthropometry and body composition using bioimpedance analysis (BIA) were obtained. During the follow-up, saliva samples from male participants were also collected to estimate testosterone and estradiol levels using the salivary ELISA kit (Salimetrics LLC, State College, PA, USA).
The body fat (percentage of body fat estimated using BIA) was strongly positively associated with relative pelvic breadths in adulthood (males = 0.64; females = 0.56, both with < 0.001). Adulthood pelvic breadth was a highly sensitive (0.81) and specific (0.74) retrospective marker of obesity during adolescence. The complex regression model (with reduction of dimensionality) including testosterone, estradiol to testosterone ratio and body fat (adolescent and adulthood) was able to describe 54.8% variability of pelvic breadth among males.
We observed that adults with a history of obesity from adolescence tend to have a wider dimension of the bony pelvis in adulthood. Based on the parameters of the adult pelvis, the history of obesity can be determined with satisfactory sensitivity and specificity (<70%). One of the explanations for this observation can be the influence of relatively elevated estrogens levels connected with excessive adiposity leading to a wider pelvis. However, the biomechanical stress connected with elevated body mass also has to be considered, as does the influence of physical activity and gait pattern on the skeletal build.
脂肪组织对发育中的个体的影响与对成年人的影响有根本区别。肥胖在性成熟过程中引起的一些变化会产生不可逆转且严重的负面影响（生育能力降低、最终身高降低、2型糖尿病），即使对于那些随后体重减轻的人也是如此。我们的研究重点是监测受性激素显著影响的骨骼结构——骨盆。成年骨盆具有强烈的性别二态性，而青少年骨盆并非如此；两性之间的骨骼差异不那么明显，且在青春期开始时才开始显现。动物模型和性别焦虑症治疗案例研究的证据表明，雌激素对骨盆上的生长板有刺激作用，导致形态变化。男性肥胖，尤其是在青春期，与性腺功能减退有关，表现为睾酮水平低和雌激素水平高。我们研究的目的是在雄激素和雌激素状态的背景下，评估青春期肥胖对成年骨盆形态的影响。
我们的样本包括238名个体（144名女性，94名男性），经过8年随访（入组时平均年龄15.2岁，随访时23.3岁）。采用生物电阻抗分析（BIA）进行人体测量和身体成分分析。在随访期间，还收集了男性参与者的唾液样本，使用唾液酶联免疫吸附测定试剂盒（Salimetrics LLC，美国宾夕法尼亚州斯泰特科利奇）来估计睾酮和雌二醇水平。
成年期的体脂（使用BIA估计的体脂百分比）与成年期相对骨盆宽度呈强正相关（男性r = 0.64；女性r = 0.56，均P < 0.001）。成年期骨盆宽度是青春期肥胖的一个高度敏感（0.81）和特异（0.74）的回顾性标志物。包括睾酮、雌二醇与睾酮比值以及体脂（青春期和成年期）的复杂回归模型（降维后）能够描述男性骨盆宽度54.8%的变异性。
我们观察到，有青春期肥胖史的成年人在成年期往往骨盆骨骼尺寸更宽。根据成年骨盆的参数，可以以令人满意的敏感性和特异性（<70%）确定肥胖史。对此观察结果的一种解释可能是，与过多脂肪相关的相对较高的雌激素水平的影响导致骨盆变宽。然而，也必须考虑与体重增加相关的生物力学压力，以及身体活动和步态模式对骨骼结构的影响。
