As saliva showed to be a noninvasive source of markers useful to monitor clinical status, the hypothesis tested was that saliva may provide reliable markers able to predict the body fat accumulation in young subjects. The salivary characteristics of 248 adolescent scholars (119 girls; 14-17 years) of flow rate, pH, phosphorus, urea, and calcium concentrations were assessed in stimulated saliva (colorimetric automated technique). The concentrations of cholesterol, 7-ketocholesterol, 25-hydroxyvitamin D2 and D3, and uric acid (UA) were measured with high-performance liquid chromatography in saliva collected at home (12-hour fast). Physical examination included height, weight, and body fat percentage (%BF) measured using bioelectric impedance to classify groups in below/above the %BF cutoff. Data were evaluated using 2-way analysis of variance and multiple linear regression. No significant difference was found in the levels of 25-hydroxyvitamin D2 and D3, cholesterol, 7-ketocholesterol, phosphorus, calcium, and urea between groups above and below %BF cutoff, and the variation in salivary flow was small. Significant sex and group effects were observed for salivary UA, which was increased in adolecents with higher %BF and in males (compared to females), without sex group interaction (power = 99.8%). Sex showed a significant effect on salivary urea, with lower levels in females. A predictive model was obtained, with salivary UA and sex explaining the variation of %BF (P < .001; power = 84%). Salivary UA showed to be an important marker of body fat accumulation in adolescents, demonstrating the clinical relevance of saliva to detect early changes and to monitor the nutritional status using a noninvasive and accurate method.

中文翻译：

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唾液尿酸是青少年体脂百分比的预测指标

由于唾液被证明是可用于监测临床状态的非侵入性标志物来源，因此测试的假设是唾液可能提供可靠的标志物，能够预测年轻受试者体内脂肪的积累。在刺激唾液中评估了 248 名青少年学者（119 名女孩；14-17 岁）的唾液特征，包括流速、pH、磷、尿素和钙浓度（比色自动技术）。胆固醇、7-酮胆固醇、25-羟基维生素 D2 和 D3 以及尿酸 (UA) 的浓度使用高效液相色谱法在家里收集的唾液中（禁食 12 小时）进行测量。体格检查包括使用生物电阻抗测量的身高、体重和体脂百分比 (%BF)，以将低于/高于 %BF 临界值的组分类。使用方差分析和多元线性回归来评估数据。25-羟基维生素 D2 和 D3、胆固醇、7-酮胆固醇、磷、钙和尿素的水平在 %BF 截断值以上和以下组之间没有显着差异，唾液流量的变化很小。对于唾液 UA 观察到显着的性别和群体效应，在没有性别群体相互作用的情况下，唾液 UA 在 %BF 较高的青少年和男性（与女性相比）中增加（功效 = 99.8%）。性别对唾液尿素有显着影响，女性的水平较低。获得了一个预测模型，唾液 UA 和性别解释了 %BF 的变化（P < .001；功率 = 84%）。唾液 UA 被证明是青少年体内脂肪积累的重要标志，