高齡老人之代謝功能與相關因子－高齡男性代謝功能與骨質密度及男性荷爾蒙之關聯

Metabolism and related factors in the elderly － Metabolic function and its association with bone mineral density and sex hormone in older men

唐憶淨(Yih-Jing Tang)

指導教授 ： 李孟智 ； 許惠恒

中山醫學大學/醫學院/醫學研究所/博士(2007年)

https://doi.org/10.6834/CSMU.2007.00013

摘要

研究背景與目的：
老年人的骨質密度隨著年齡增長而下降，性荷爾蒙的分泌也逐漸減少。疾病會造成生活功能障礙，其中代謝症候群（metabolic syndrome）指一群與新陳代謝退化有關的症狀，文獻發現有代謝症候群的人將來罹患糖尿病合併心血管疾病的機率較高，但大多研究對象為中年族群，少有針對老年人為主題之研究報告。老化容易導致骨質流失，造成骨質疏鬆，若不慎跌倒，脊椎骨折及髖關節骨折的發生率都隨年齡升高。研究指出心血管疾病與骨質疏鬆可能有共同的危險因子。目前探討代謝症候群與骨質密度相關性的文獻不多，值得深入研究。而男性荷爾蒙除了作用在泌尿生殖系統外，它在全身包括心血管系統及新陳代謝功能上亦扮演特殊的角色。但其機轉仍不清楚，也不像對女性荷爾蒙的研究那麼多。
研究材料與方法：
本研究以自費安養中心之榮民為對象，平均年齡為78.8歲。每一位受試者皆知情同意並簽署同意書。為老年人測量跟骨骨質密度、體脂肪組成，記錄實際身高、體重、血壓、脈搏，視力、聽力、腰臀圍、六分鐘行走距離等。抽血檢測與代謝症候群相關因子如空腹血糖、血脂肪－三酸甘油脂及高密度脂蛋白，肝功能、腎功能、尿酸，血液常規以及尿液常規檢查等。另外還測定血清發炎指標如高敏感性C反應蛋白（hs-CRP），男性睪固酮（testosterone）與性激素結合蛋白（簡稱SHBG）等。
研究結果：
研究結果顯示這群高齡男性之跟骨骨質密度與身體質量指數（BMI）、血中三酸甘油脂濃度及六分鐘行走距離有顯著正相關。血清睪固酮則與身體質量指數、空腹血糖、空腹血清hs-CRP、白血球數目呈顯著負相關，唯與血紅素濃度呈顯著正相關。而且發現符合新陳代謝症候群診斷標準的老年男性的平均血清睪固酮濃度較低；換言之，血清睪固酮濃度較低之高齡男性罹患新陳代謝症候群的比率較高，達到統計上顯著差異（P<0.001）。
討論與建議：
本研究重點在探討高齡男性骨質密度與血清睪固酮的變化，及代謝功能對骨質密度與男性荷爾蒙之影響，在老化過程中所扮演的角色。希望藉此研究發現男性老化後骨質密度與性荷爾蒙的變化情形，與老化過程有特定的相關性。並探討影響老化的因素如心血管疾病之危險因子，新陳代謝症候群、胰島素抗性等，以逐步深入了解老化的多樣性機轉。目前醫療政策漸由治療轉為預防，提倡多元化、全方位的銀髮族健康服務。本研究提供臨床醫療人員照顧老年人之重要參考，並致力減緩因老年退化產生之慢性疾病，以及醫政單位進一步研擬對策，朝促進長壽健康的老年而努力。

關鍵字

老年人 ； 代謝症候群 ； 骨質密度 ； 骨質疏鬆 ； 睪固酮 ； 男性

並列摘要

Background: Decline of bone density and sex hormone remarkably decreases metabolic function in elderly men. This deficiency may relate to many degenerative diseases. However, the role of metabolic parameters and physical activity influencing older men’s bone and hormone status remains unclear.
Objective: To evaluate calcaneus bone mass and serum testosterone concentration in elderly men, and the associated physical, metabolic and inflammatory factors; and the relationship of metabolic syndrome to testosterone levels.
Methods: This is a cross-sectional study. Older veterans living in a veterans’ home (average age: 78.8 years) were enrolled. We measured body heights and weights, waist and hip circumferences, body fat, lean body mass, blood pressure, 6 minute walking distance, complete blood count and blood biochemical profile and high sensitivity C-reactive protein (hs-CRP). 381 participants were eligible for analysis of serum total testosterone and sex hormone binding globulin (SHBG). Free testosterone was calculated by Nanjee-Wheeler’s method. 368 subjects received Soundscan quantitative ultrasound over right calcaneus, broadband ultrasound attenuation (BUA) and T-score were recorded.
Results:
I. The range of calcaneus BUA was 27.3 ~ 134.0, T-score was -4.78 ~ 3.43. Of the total participants, 36.4% were osteopenic (-2.5＜T-score＜-1.0), and 16.3% were osteoporotic (T-score≦-2.5). BUA correlated with weight, body mass index (BMI), waist circumference, hip circumference, body fat, lean body mass, serum triglycerides, high density lipoprotein-cholesterol, albumin, pre-albumin, fasting and PC-2hour blood insulin, red blood cell count, hemoglobin concentration and 6-minute walking distance. Multiple regression stepwise analysis revealed that only BMI, distance of 6-minute walking and blood triglyceride level were independently and positively associated with the values of BUA.
II. Serum total testosterone levels were 0.20 ~ 15.74 ng/ml, free testosterone 11.78 ~ 478.31 pmol/L. Total testosterone correlated negatively with body mass index (BMI), waist-hip ratio, body fat, blood glucose, blood insulin, hemoglobin-A1c, serum triglyceride, white blood cell (WBC) count and hs-CRP; but positively with high-density-lipoprotein-cholesterol (HDL-C) and hemoglobin. Multiple regression stepwise forward analysis revealed that BMI values, fasting blood glucose, WBC count, fasting hs-CRP and hemoglobin were independent factors related to total testosterone. Furthermore, total testosterone is lower in elderly men with metabolic syndrome, according to National Cholesterol Education Program criteria with a modification of waist circumference. However, free testosterone plays little role in association with metabolic factors in this elderly men’s population.
Conclusion: Calcaneus bone mass is significantly and positively associated with BMI, blood triglycerides and 6-minute walking distance in older men. Total testosterone level is significantly related to metabolic and inflammatory factors in elderly men. Low total testosterone may be a significant indicator for development of metabolic syndrome in elderly men.

並列關鍵字

Bone density ； older men ； body mass index ； triglyceride ； elderly ； testosterone ； aging ； metabolic syndrome ； inflammation

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