美國一項研究顯示，在一項對包括了大約300萬名成年人的近100項研究的所做的分析顯示，相對於正常體重而言，總體上的肥胖（將所有等級的肥胖結合在一起）及較嚴重的肥胖程度皆與顯著的、更高的全因死亡風險有關，而體重超重則與顯著較低的全因死亡率有關。1月2日《美國醫學會雜誌》（JAMA）上。
根據文章的背景資料：“對與正常體重、超重及肥胖相聯係的相關死亡風險的估計可為臨床決策提供幫助。”
美國馬裏蘭州海厄茨維爾市的疾病控製及預防中心旗下的國家衛生統計中心的Katherine M. Flegal及其同事開展了一項研究，旨在對已經發表過的體質指數（BMI）和全因死亡率的分析進行編撰和總結，它們可為標準的BMI部類提供風險比（HRs）。為了綜述及薈萃分析，研究人員確認了符合納入標準的97項研究，它們提供的組合樣本規模超過了288萬名個人及超過27萬例的死亡事件。參與者來自的地區包括了美國或加拿大（n = 41項研究）、歐洲（n = 37）、澳大利亞（n = 7）、中國或中國台灣（n = 4）、日本（n = 2）、巴西（n = 2）、以色列（n = 2）、印度（n = l）及墨西哥（n = l）。
超重（BMI：25-<30）、肥胖症 (BMI： ≥30)、第一級肥胖 (BMI：30-<35) 、第二級和第三級肥胖 (BMI：≥35) 的全因死亡HRs的計算是相對於正常體重(BMI：18.5-<25)的。
研究人員發現，總結性的HRs表明，超重的死亡風險下降了6%；肥胖（所有等級）的死亡風險增加了18%；第一級肥胖的死亡風險下降了5%；而第二級和第三級肥胖的死亡風險增加了29%。
文章的作者寫道，發現第一級肥胖與增加了的死亡率沒有關係， 這表明，增加了的肥胖症死亡率可能主要是由較在嚴重BMI等級上的、增加了的死亡率引起的。
研究人員補充說，他們的發現與所觀察到的超重及適度肥胖患者有著較低的死亡率是一致的。 “對這種現象的可能的解釋包括體重較重的患者的早期症狀的表現、患者有較大的接受最佳藥物治療的可能性、身體脂肪增加所帶來的保護心髒的代謝效應及較高代謝儲備的裨益等。”
文章的作者得出結論，使用預定義的標準BMI分組可促進各項研究間的比較。
相關鏈接：Association of All-Cause Mortality With Overweight and Obesity Using Standard Body Mass Index Categories:
ImportanceEstimates of the relative mortality risks associated with normal weight, overweight, and obesity may help to inform decision making in the clinical setting.
ObjectiveTo perform a systematic review of reported hazard ratios (HRs) of all-cause mortality for overweight and obesity relative to normal weight in the general population.
Data SourcesPubMed and EMBASE electronic databases were searched through September 30, 2012, without language restrictions.
Study SelectionArticles that reported HRs for all-cause mortality using standard body mass index (BMI) categories from prospective studies of general populations of adults were selected by consensus among multiple reviewers. Studies were excluded that used nonstandard categories or that were limited to adolescents or to those with specific medical conditions or to those undergoing specific procedures. PubMed searches yielded 7034 articles, of which 141 (2.0%) were eligible. An EMBASE search yielded 2 additional articles. After eliminating overlap, 97 studies were retained for analysis, providing a combined sample size of more than 2.88 million individuals and more than 270 000 deaths.
Data ExtractionData were extracted by 1 reviewer and then reviewed by 3 independent reviewers. We selected the most complex model available for the full sample and used a variety of sensitivity analyses to address issues of possible overadjustment (adjusted for factors in causal pathway) or underadjustment (not adjusted for at least age, sex, and smoking).
ResultsRandom-effects summary all-cause mortality HRs for overweight (BMI of 25-<30), obesity (BMI of ≥30), grade 1 obesity (BMI of 30-<35), and grades 2 and 3 obesity (BMI of ≥35) were calculated relative to normal weight (BMI of 18.5-<25). The summary HRs were 0.94 (95% CI, 0.91-0.96) for overweight, 1.18 (95% CI, 1.12-1.25) for obesity (all grades combined), 0.95 (95% CI, 0.88-1.01) for grade 1 obesity, and 1.29 (95% CI, 1.18-1.41) for grades 2 and 3 obesity. These findings persisted when limited to studies with measured weight and height that were considered to be adequately adjusted. The HRs tended to be higher when weight and height were self-reported rather than measured.
Conclusions and RelevanceRelative to normal weight, both obesity (all grades) and grades 2 and 3 obesity were associated with significantly higher all-cause mortality. Grade 1 obesity overall was not associated with higher mortality, and overweight was associated with significantly lower all-cause mortality. The use of predefined standard BMI groupings can facilitate between-study comparisons.
ImportanceEstimates of the relative mortality risks associated with normal weight, overweight, and obesity may help to inform decision making in the clinical setting.
ObjectiveTo perform a systematic review of reported hazard ratios (HRs) of all-cause mortality for overweight and obesity relative to normal weight in the general population.
Data SourcesPubMed and EMBASE electronic databases were searched through September 30, 2012, without language restrictions.
Study SelectionArticles that reported HRs for all-cause mortality using standard body mass index (BMI) categories from prospective studies of general populations of adults were selected by consensus among multiple reviewers. Studies were excluded that used nonstandard categories or that were limited to adolescents or to those with specific medical conditions or to those undergoing specific procedures. PubMed searches yielded 7034 articles, of which 141 (2.0%) were eligible. An EMBASE search yielded 2 additional articles. After eliminating overlap, 97 studies were retained for analysis, providing a combined sample size of more than 2.88 million individuals and more than 270 000 deaths.
Data ExtractionData were extracted by 1 reviewer and then reviewed by 3 independent reviewers. We selected the most complex model available for the full sample and used a variety of sensitivity analyses to address issues of possible overadjustment (adjusted for factors in causal pathway) or underadjustment (not adjusted for at least age, sex, and smoking).
ResultsRandom-effects summary all-cause mortality HRs for overweight (BMI of 25-<30), obesity (BMI of ≥30), grade 1 obesity (BMI of 30-<35), and grades 2 and 3 obesity (BMI of ≥35) were calculated relative to normal weight (BMI of 18.5-<25). The summary HRs were 0.94 (95% CI, 0.91-0.96) for overweight, 1.18 (95% CI, 1.12-1.25) for obesity (all grades combined), 0.95 (95% CI, 0.88-1.01) for grade 1 obesity, and 1.29 (95% CI, 1.18-1.41) for grades 2 and 3 obesity. These findings persisted when limited to studies with measured weight and height that were considered to be adequately adjusted. The HRs tended to be higher when weight and height were self-reported rather than measured.
Conclusions and RelevanceRelative to normal weight, both obesity (all grades) and grades 2 and 3 obesity were associated with significantly higher all-cause mortality. Grade 1 obesity overall was not associated with higher mortality, and overweight was associated with significantly lower all-cause mortality. The use of predefined standard BMI groupings can facilitate between-study comparisons.
ImportanceEstimates of the relative mortality risks associated with normal weight, overweight, and obesity may help to inform decision making in the clinical setting.
ObjectiveTo perform a systematic review of reported hazard ratios (HRs) of all-cause mortality for overweight and obesity relative to normal weight in the general population.
Data SourcesPubMed and EMBASE electronic databases were searched through September 30, 2012, without language restrictions.
Study SelectionArticles that reported HRs for all-cause mortality using standard body mass index (BMI) categories from prospective studies of general populations of adults were selected by consensus among multiple reviewers. Studies were excluded that used nonstandard categories or that were limited to adolescents or to those with specific medical conditions or to those undergoing specific procedures. PubMed searches yielded 7034 articles, of which 141 (2.0%) were eligible. An EMBASE search yielded 2 additional articles. After eliminating overlap, 97 studies were retained for analysis, providing a combined sample size of more than 2.88 million individuals and more than 270 000 deaths.
Data ExtractionData were extracted by 1 reviewer and then reviewed by 3 independent reviewers. We selected the most complex model available for the full sample and used a variety of sensitivity analyses to address issues of possible overadjustment (adjusted for factors in causal pathway) or underadjustment (not adjusted for at least age, sex, and smoking).
ResultsRandom-effects summary all-cause mortality HRs for overweight (BMI of 25-<30), obesity (BMI of ≥30), grade 1 obesity (BMI of 30-<35), and grades 2 and 3 obesity (BMI of ≥35) were calculated relative to normal weight (BMI of 18.5-<25). The summary HRs were 0.94 (95% CI, 0.91-0.96) for overweight, 1.18 (95% CI, 1.12-1.25) for obesity (all grades combined), 0.95 (95% CI, 0.88-1.01) for grade 1 obesity, and 1.29 (95% CI, 1.18-1.41) for grades 2 and 3 obesity. These findings persisted when limited to studies with measured weight and height that were considered to be adequately adjusted. The HRs tended to be higher when weight and height were self-reported rather than measured.
Conclusions and RelevanceRelative to normal weight, both obesity (all grades) and grades 2 and 3 obesity were associated with significantly higher all-cause mortality. Grade 1 obesity overall was not associated with higher mortality, and overweight was associated with significantly lower all-cause mortality. The use of predefined standard BMI groupings can facilitate between-study comparisons.
ImportanceEstimates of the relative mortality risks associated with normal weight, overweight, and obesity may help to inform decision making in the clinical setting.
ObjectiveTo perform a systematic review of reported hazard ratios (HRs) of all-cause mortality for overweight and obesity relative to normal weight in the general population.
Data SourcesPubMed and EMBASE electronic databases were searched through September 30, 2012, without language restrictions.
Study SelectionArticles that reported HRs for all-cause mortality using standard body mass index (BMI) categories from prospective studies of general populations of adults were selected by consensus among multiple reviewers. Studies were excluded that used nonstandard categories or that were limited to adolescents or to those with specific medical conditions or to those undergoing specific procedures. PubMed searches yielded 7034 articles, of which 141 (2.0%) were eligible. An EMBASE search yielded 2 additional articles. After eliminating overlap, 97 studies were retained for analysis, providing a combined sample size of more than 2.88 million individuals and more than 270 000 deaths.
Data ExtractionData were extracted by 1 reviewer and then reviewed by 3 independent reviewers. We selected the most complex model available for the full sample and used a variety of sensitivity analyses to address issues of possible overadjustment (adjusted for factors in causal pathway) or underadjustment (not adjusted for at least age, sex, and smoking).
ResultsRandom-effects summary all-cause mortality HRs for overweight (BMI of 25-<30), obesity (BMI of ≥30), grade 1 obesity (BMI of 30-<35), and grades 2 and 3 obesity (BMI of ≥35) were calculated relative to normal weight (BMI of 18.5-<25). The summary HRs were 0.94 (95% CI, 0.91-0.96) for overweight, 1.18 (95% CI, 1.12-1.25) for obesity (all grades combined), 0.95 (95% CI, 0.88-1.01) for grade 1 obesity, and 1.29 (95% CI, 1.18-1.41) for grades 2 and 3 obesity. These findings persisted when limited to studies with measured weight and height that were considered to be adequately adjusted. The HRs tended to be higher when weight and height were self-reported rather than measured.
Conclusions and RelevanceRelative to normal weight, both obesity (all grades) and grades 2 and 3 obesity were associated with significantly higher all-cause mortality. Grade 1 obesity overall was not associated with higher mortality, and overweight was associated with significantly lower all-cause mortality. The use of predefined standard BMI groupings can facilitate between-study comparisons.
