本帖最後由 lsc0019 於 2009-6-3 09:41 編輯
作者：Samuel I. Beard, Jr
出處：WebMD醫學新聞
May 19, 2009(德州休士頓) — 根據發表於美國臨床內分泌醫師協會第18屆年會暨臨床研討會的研究，身體質量指數(BMI)高的血壓正常年輕男性，醛固酮值過高可能可以作為心血管疾病的標記。不過，該研究進行的樣本相對較少，且相關資料並未顯示因果關係。
主要研究者、喬治亞醫藥學院醫學院的Dayal D. Raja醫師表示，每年約有300,000例與肥胖相關的死亡，其中大部份是心因性。美國在過去30年間，肥胖比率增加兩倍，世界其他國家也是。我們的小孩也有多數發生心臟傷害。如果我們及早篩檢肥胖病患，我們就可以瞭解並及早治療他們。
不過，Raja醫師表示，本研究只有顯示相關資料而無因果關係。早期的心臟傷害是無症狀的，等到它變成有症狀時，已經太晚了。
研究對象是126名健康的血壓正常年輕人，年紀15至17歲，有正常血壓。其中，47%是非裔美國人、55%是男性。沒有人有醫療史、也沒有人現在正在服用降血壓藥物。使用BMI測量肥胖症，使用不定期量測之收縮壓、相對心壁厚度、左心室質量(LVM)來測量心血管風險。研究對象接受一週標準建議下的鈉控制飲食，之後測量醛固酮值。
研究發現，多數脂肪細胞產生醛固酮，過多的醛固酮引起過多的鈉與水滯留，而增加血壓。
使用性別相關分析時，整體(r= 0.219；P< .01)與男性(r= .452；P< .0001)的較高醛固酮值與BMI增加有顯著關聯，但是女性則沒有。男性醛固酮值增加也與不定期量測之收縮壓較高(r= 0.376；P< .001)，較厚的相對心壁厚度(r= 0.278；P< .02)與較大的LVM (r= 0.306；P< .001)有關。
Raja醫師與研究團隊結論表示，該發現支持需要對年輕、血壓正常的肥胖男性進行皮質醛固酮分泌過多症篩檢，且治療此狀況，以避免這些人之前高醛固酮值相關未確認的早期心血管損傷。
紐約Stony Brook大學醫學中心醫學助理教授Harmeet Singh Narula醫師形容該研究為一個引起興趣的現代觀念。
於年會中擔任海報評審、未參與本研究的Narula醫師表示，如果你治療原發性皮質醛固酮分泌過多症病患，可能會感覺到可以讓血壓正常化，但是依舊無法逆轉原發性皮質醛固酮分泌過多症時發生的傷害。
他指出，本研究對於後續評估來說是個好觀念，但目前還無法用來改變實務，因為需要進行有更大樣本的更多研究。
Narula醫師接著表示，心臟超音波顯示心肌或心跳縮短的改變，這顯然是可以考量進行觀察且有趣的，因為LVM的改變有時候是可以比較快發現的。
美國臨床內分泌醫師協會(AACE)第18屆年會與臨床研討會：摘要100。發表於2009年5月14日。
AACE 2009: Elevated Aldosterone Levels May Indicate Early CV Damage in Young Men
By Samuel I. Beard, Jr
Medscape Medical News
May 19, 2009 (Houston, Texas) — Excessive levels of aldosterone in normotensive young men with a high body mass index (BMI) could serve as a marker for cardiovascular disease, according to a study presented here at the American Association of Clinical Endocrinologists 18th Annual Meeting and Clinical Congress. However, the study was conducted on a relatively small sample and resulted in correlation data that do not show cause and effect.
"About 300,000 deaths annually are related to obesity, and the vast majority of those are cardiac in origin," said lead investigator Dayal D. Raja, MD, from the Medical College of Georgia School of Medicine in Augusta. "There's been a 2-fold increase in obesity rates in the United States over the past 3 decades, and even [in] the rest of the world. A significant number of our kids will develop cardiac damage. If we were to screen obese patients early, then we could pick up on that and treat them early."
However, Dr. Raja said that this study showed correlation data only, not cause and effect. "Early cardiac damage is asymptomatic, and by the time it becomes symptomatic, it's too late."
The study was conducted on 126 healthy normotensive youths, aged 15 to 17 years, who had normal blood pressure. Of these subjects, 47% were African American and 55% were men. None had past medical history or were currently taking medicines to control blood pressure or hypertension. BMI was used as a measure of adiposity, and casual systolic blood pressure, relative wall thickness, and left ventricular mass (LVM) were used as measures of cardiovascular risk. The subjects were placed on a sodium-controlled diet under standard recommended conditions for 1 week, after which aldosterone levels were measured.
The study found that a large number of fat cells produced aldosterone, and this excessive aldosterone caused excessive sodium and water retention and increased blood pressure .
In the analysis using "gender-pooled data," higher aldosterone levels and increased BMI were significantly associated overall (r?= 0.219; P?< .01) and in men (r?= .452; P?< .0001), but not in women. Increased aldosterone levels in men were also associated with higher casual systolic blood pressure (r?= 0.376; P?< .001), greater relative wall thickness (r?= 0.278; P?< .02), and larger LVM (r?= 0.306; P?< .001).
The findings "support the need to screen for hyperaldosteronism in young, normotensive obese males and to treat this condition in order to prevent previously unrecognized early cardiovascular damage associated with high aldosterone levels in this population," Dr. Raja and his team conclude.
Harmeet Singh Narula, MD, FACP, FACE, assistant professor of medicine at Stony Brook University Medical Center in New York, called the study "an intriguing and modern concept."
"If you treat people with primary hyperaldosteronism medically itself, there's a feeling that you may be able to normalize the blood pressure but still not be able to reverse the damage that has happened with primary hyperaldosteronism," said Dr. Narula, who served as a judge for the posters at this year's conference and who was not involved with the study.
He added that this study is "a good concept to evaluate further, but it's not something to change practice at this time" because more research needs to be done with a larger sample size.
"The [echocardiographic] findings show changes in the heart muscle or the way the heart shortens?.?.?. and it's clearly concerning to see that, and interesting because [LVM changes are] something that you can see much sooner," Dr. Narula continued.
American Association of Clinical Endocrinologists (AACE) 18th Annual Meeting and Clinical Congress: Abstract 100. Presented?May 14, 2009. |
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