研究背景與目的:近二十年間,研究者發現憂鬱症與骨質流失間關聯性不斷被驗證存在顯著負相關;若排除常見年齡、藥物或生活習慣因素影響,仍有不少證據指向憂鬱症是個潛在骨鬆危險因子。隨年紀越大,雌激素變化造成女性骨質流失風險提升,且,女性本身較高的情緒感受度與反應性,亦增加心理性因素誘發骨鬆之風險有更甚於男性的可能;上述原因皆可窺見女性之所以為常見骨鬆高危險群的原因。為探究憂鬱誘導骨質流失之關聯途徑,本研究主體假設為憂鬱個體自律神經系統存在異常病理因素故有較低骨密度;研究假設亦將同時檢證憂鬱症個案與其骨密度、以及憂鬱症狀與自律神經系統運作之關聯性。 研究方法:本研究屬於2X3二因子混合設計,憂鬱組別為受試者間變項,依臨床篩選條件分為憂鬱組、無憂鬱症組;實驗情境為受試者內變項,分為基準期、壓力期與恢復期,共三情境。共有53位女性同意參與研究,實驗情境操弄下以生理回饋儀記錄兩組受試者於不同實驗情境下表現之呼吸振幅、皮膚傳導電位、溫膚、末梢血流脈搏、與心跳變異率等與自律神經系統相關之壓力心理生理指標,並完成相關量表以及檢查室DXA骨密度測量。統計方面,以F檢定進行組別間以及變項間之差異分析;以Pearson相關探討各變項間之關聯程度。 研究結果:憂鬱組於腰椎BMD、左髖骨T分數以及左髖骨Z分數皆顯著低於無憂鬱症組,而全體受試者憂鬱症狀多與骨密度呈負相關,尤其與腰椎BMD間達顯著負相關。自律神經異常之假設驗證結果顯示,本研究於實驗操弄具某程度有效性,雖然憂鬱組與無憂鬱症組於各項壓力心理生理指標皆未達顯著差異,但十二項心理生理指標中,共有六項指標與骨密度呈顯著相關,七項指標與腰椎、抑或左髖骨骨密度呈邊緣顯著相關;十二項頻域分析之心跳變異率指標中,則有七項指標與左髖骨骨密度呈顯著相關。 討論:即便年齡層不及常見高齡之骨鬆高危險群,本研究實徵結果可見憂鬱症與骨密度存在顯著負相關。較值得注意之處為,儘管受限於樣本數、施測環境欠缺標準化,本研究仍有兩項主要發現。一為,憂鬱個案可能存在失調之交感迷走神經調節功能;再者,個體自律神經系統之相關壓力心理生理指標與骨密度間存在顯著相關,尤以特定情境之皮膚傳導電位、頻域分析心跳變異率關聯強度最大。但憂鬱症個案是否藉由異常自律神經系統運作途徑誘發骨質流失,此論點仍待更完善評估。
Background: Reports of negative correlation between major depressive disorder and osteoporosis have been continuously filed since its discovery more than twenty years ago. Taking the effects of ages, drugs, and living style into consideration, multiple reports have shown that depression is a potential risk factor to bone loss. As females become older, they are more susceptible to physical risk factors than males, because decreasing level of hormone makes females have lesser physical protection than males. Besides, females are more sensitive and have a more reactive emotion characteristic compares to males. Based on the above two main reasons, it would be interesting to study the correlation between associated-pathways and depression-induced osteoporosis when focus on females with specific vulnerabilities. Our main hypothesis is that depressive clients have a dysfunction of autonomic nerve system which leads to bone loss. Therefore, we will study the association between depressive symptoms and bone mineral density. Lastly, we will also look into the role that autonomic nerve system plays between depressive symptoms and the stress psychophysiological reactivities of autonomic nervous system (e.g. breathing amplitude, skin conductance, temperature, and heart rate variability related indices). Method: This study is a 2×3 experimental design (group × situation). Inter-variable includes depressed and non-depressed group. Intra-variables include three experimental phases: baseline, stress, and recovery phase. 53 female participants went through three experimental procedures and their psychophysiological reactivities were recorded by the biofeedback machine (ProComp InfiniteTM). Self-reporting scales and DXA examination are also acquired after every participant has signed up the inform consent for all the study protocols. F test and Pearson’s r are statistical methods we used to examine the difference between groups, and to find out the degree of the association between two variables, respectively. Result: Compared to non-depressed group, depressed group showed significantly lower values in lumbar bone mineral density (BMD), left hip T-score and left hip Z-score. The correlation between depressive symptoms and some of the bone mineral density indices showed significant negativity within all participants, especially with some lumbar BMD indices. We have testified that different phases exert certain reversible effects on the participants’ autonomic regulations that aligned with our hypothesis. Even though there was no significant difference showed up between two groups, we found seven out of twelve psychophysiological indices were significantly related to bone values, and eight indices were borderline significantly related on the other hand. Also, within frequency domain heart rate variability (HRV) indices, nine out of twelve indices were significantly related to left hip BMD, T-score, and Z-score. Discussion: Even though the females in this study were younger than those usual high risk osteoporotic groups are, the results still demonstrated the relationship between major depressive disorder and BMD. In particular, the correlation was significantly negative between psychophysiological indices and BMD regardless of some limitations such as, sample size and unstandardized experimental environment. Notably, our study have two main findings, first, females with major depressive disorder might have a certain possibility about the dysfunction regulation of sympathovagal nerves. Still, among all psychophysiological indices examined, skin conductance, LF, LF/HF are highly correlated with different BMD values. However, whether depression-induced osteoporosis is mediated by autonomic nervous system and what route is involved are issues in need of further investigation.