過重和健康體重小孩的膽固醇值很早就有持續的差異
作者：Brian Hoyle
出處：WebMD醫學新聞
May 13, 2010 (英屬哥倫比亞溫哥華) — 根據發表於小兒科協會2010年會的新研究，過重小孩的脂質數值風險較大，意味著他們的心血管疾病風險較高。
發表人、北卡羅來納大學教堂山分校醫學院一般小兒科與青少年醫學系小兒科助理教授Asheley C. Skinner博士向Medscape Pediatrics表示，在各年齡層，過重孩童的各項脂質數據都比健康體重的小孩差，再者，這些差異隨著年紀更加明顯，特別是青春期。
研究者分析了自1999至2006年的「National Health and Nutrition Education Survey (NHANES)」研究之部份資料獲得這項結論，測量孩童與青少年空腹至少8小時後的總膽固醇(TC)、低密度脂蛋白(LDL)、高密度脂蛋白(HDL)與三酸甘油脂，如果研究對象的身體質量指數(BMI)超過第85百分位則被歸類為過重，如果BMI 介於第5-85百分位則被視為健康體重。
過重組包括1959名年紀3-17歲者，健康組包括3119名年紀相仿者。
使用最小均方演算法修勻檢視的資料，使用平均值和變異值建立各年齡的曲線。
Skinner博士表示，雖然這些曲線無法用來檢視各年齡個體間的差異(這是橫斷面資料的已知限制)，它提供了一個有力的方式探討整個族群隨著時間的改變。
Skinner博士的團隊建立了TC、LDL、HDL和空腹三酸甘油脂的曲線，標示出過重(設定為第95百分位)女孩和男孩以及健康體重者(設定為第75百分位)的資料。
Skinner博士報告指出，一般而言，依據不同的脂質，實際值與時間(8 -11年)有所差異，所有曲線都呈現同樣的起伏模式，一開始偏低、之後到達高峰，然後是一個不同斜率的波谷，最後，在16和17歲時有各種變化的增加。
Skinner博士指出，在TC、LDL與三酸甘油脂曲線中，模式相似，過重小孩的脂質隨著年紀範圍增加，到了青春期，差異更加明顯。至於HDL曲線則是相反，這個好膽固醇的數值在健康體重的小孩比較高。
Skinner博士報告指出，三酸甘油脂的情況特別明顯，過重小孩的數值在4歲時就開始急遽增加，這個情況持續，到青少年時更是達到相當相當高的數據，過重小孩在約8歲時，這個數據就超過200 mg/dL，且隨著年紀增加，到了16歲時，達到250 mg/dL。
Skinner博士表示，這些結果認為，過重孩童的異常脂質數據可能會持續且累加。
雖然研究者繼續分析現有的資料，但需要以更大型的資料庫，對包括種族在內等特定因素的特定資料進行更多分析。
北卡羅來納大學營養學教授、體育科學與運動教授Robert G. McMurray醫師向Medscape Pediatrics表示，我們注意到，北卡羅來納的孩童有類似的趨勢，研究顯示，肥胖孩童消耗的熱量比健康體重的同儕少。
McMurray醫師表示，如果攝取的熱量低，肥胖孩童的休息代謝速率可能會低於正常值；有一些資料支持這一點。另外，肥胖孩童可能比較少活動而需要較少的熱量，致使休息代謝速率降低了。如果他們的休息代謝速率較低且他們較少活動，那就不難發現何以他們會一直肥胖。
McMurray醫師的研究也顯示，肥胖孩童增加的膽固醇值和體能活動無關。
國家兒童健康與發展研究中心以及婦女健康計畫的Building Interdisciplinary Careers資助該研究。作者們皆宣告沒有相關財務關係。
小兒科學院2010年會：論壇小組4140.3。發表於2010年5月4日。
Early, Persistent Differences in Cholesterol Levels Between Overweight and Healthy Weight Children
By Brian Hoyle
Medscape Medical News
May 13, 2010 (Vancouver, British Columbia) — Children who are overweight run a greater risk of having lipid profiles that signal a high risk for cardiovascular disease, and risk gets progressively higher with age, according to new research presented here at the Pediatric Academic Societies 2010 Annual Meeting.
"Overweight children have worse lipid profiles than healthy [weight] children for all lipid components at all ages of childhood. Moreover, the differences become more pronounced with age, particularly around the time of puberty," study presenter Asheley C. Skinner, PhD, assistant professor of pediatrics, Department of General Pediatrics and Adolescent Medicine, University of North Carolina at Chapel Hill School of Medicine, told Medscape Pediatrics.
To reach this conclusion, the researchers analyzed data compiled as part of the National Health and Nutrition Education Survey (NHANES) from 1999 to 2006. Total cholesterol (TC), low-density lipoproteins (LDL), high-density lipoproteins (HDL), and triglycerides were measured in children and adolescents after a fast of at least 8 hours. The participants were categorized as overweight if their body mass index (BMI) exceeded the 85th percentile and as healthy weight if their BMI ranged from the 5th to the 85th percentile.
The overweight group consisted of 1959 children 3 to 17 years of age and the healthy weight group consisted of 3119 age-matched counterparts.
The data were examined using least mean square smoothing, in which mean and variance values are used to create curves across age.
Although the curves cannot be used to examine differences in individuals with age, an "acknowledged limitation of cross-sectional data," Dr. Skinner said, it offers a powerful means of viewing changes in populations over time.
Dr. Skinner's team constructed curves for TC, LDL, HDL, and fasting triglycerides, plotting data for girls and boys who were overweight (the 95th percentile was selected) and healthy weight (the 75th percentile was selected).
In general, all curves displayed the same undulating pattern, with an initial trough followed by a climb to a peak that, depending on the lipid, varied in actual value and time (8 to 11 years), followed by a trough that varied in slope and, finally, by a variable rise for those aged 16 and 17 years of age, Dr. Skinner reported.
In the TC, LDL, and triglyceride curves, the pattern was similar, with lipids being elevated in overweight children all along the age range, and the differences becoming more pronounced around adolescence. The situation was reversed in the HDL curves, where the levels of the good cholesterol were consistently higher in the healthy weight children, Dr. Skinner noted.
The situation for triglycerides was particularly dramatic, with a precipitous rise in overweight children beginning at about 4 years of age. The levels were maintained, producing "much, much higher values" in adolescence, Dr. Skinner reported. The levels exceeded 200?mg/dL in overweight children by the time they were about 8 years of age, and consistently increased with age, hitting 250?mg/dL by age 16.
"These results suggest that abnormal lipid values may persist and accumulate in overweight children throughout childhood," said Dr. Skinner.
Although the researchers continue to analyze the available data, teasing out more specific information on specific factors, including ethnicity, a larger database is required.
"We have noticed a similar trend in our North Carolina children," with a study showing that obese children report consuming fewer calories than their healthy weight peers, Robert G. McMurray, MD, professor of exercise and sport science and professor of nutrition at the University of North Carolina, in Durham, told Medscape Pediatrics.
"If the caloric intake is low, the resting metabolic rates of the obese children may be lower than normal; there are some data to support this. Alternatively, the obese children may be less active and require fewer calories, [leading to] a lower resting metabolic rate. If their resting metabolic rates are lower and they are less active, then it is easy to see how they could remain obese," Dr. McMurray said.
Dr. McMurray's research also shows that elevated cholesterol levels in obese children are independent of physical activity.
The study was funded by grants from the National Institute of Child Health and Development and the Building Interdisciplinary Careers in Women's Health program. The authors have disclosed no relevant financial relationships.
Pediatric Academic Societies (PAS) 2010 Annual Meeting: Platform session?4140.3. Presented May?4, 2010.
