老年人腹部脂肪（CT测量）分布与体质指数及代谢综合征的关系

Association of abdominal fat distribution by computed tomography with body mass index and metabolic syndrome in Chinese elders

目的 研究老年人腹部脂肪分布的特点与体质指数（BMI）及代谢综合征（MS）的关系.方法 收集2009年1月至2010年12月于解放军总医院放射科行腹部CT检查、≥65岁患者的临床资料和腹部CT图像,按照不同年龄、BMI值进行分组,另选择同期一组正常体重、≥65岁的老年患者和BMI与正常体重老年患者相匹配的中年（40～ 60岁）患者腹部CT图像作对照,比较分析老年人腹部脂肪分布的特点和影响因素.腹部CT取L4/L5椎间隙水平面图像传至GE工作站,用专项软件计算腹内脂肪面积（VFA）和皮下脂肪面积（SFA）.结果 纳入研究的腹部CT图像共390例（男252例,女138例）,腹部总脂肪面积（TAF）女性与男性差异无统计学意义[（323±122）比（303±141） cm2,P=0.146],用身高校正后,女性TAF明显高于男性[（128±49）比（105±49） cm2/m2,P=0.000].按BMI分层计算,可见TAF、VFA、SFA值随BMI值增高而逐渐增加.按年龄分层（＞65 ～75岁组,＞ 75 ～ 85岁组,＞85岁组）比较各值间的变化未能看到TAF、VFA和SFA随着年龄的增加而增多.与正常体重的老年人、BMI匹配中年人比较,有MS者TAF、VFA、SFA增高,且随着MS积分的增加而逐渐增加;但以仅有一种MS组分分组,单有糖尿病、高血脂或高血压的老年组与对照老年组的TAF、VFA、SFA值差异均无统计学意义.Logistic回归分析显示,VFA值大（男：OR=1.03,95％CI：1.012～1,047;女：OR=1.06,95％CI：1.026～1.088）是老年人发生MS的危险因素,年龄、皮下脂肪均不是影响老年人发生MS的因素（均P＞0.05）.结论 老年女性较男性TAF明显高;增龄不增加老年人的腹部脂肪面积.TAF、VFA、SFA值随BMI值增高而逐渐增加,有高度相关性.≥2个MS组分叠加时TAF、VFA、SFA各值均明显增大,其中VFA是老年人发生MS的危险因素.

Objective To explore the gender and age difference of abdominal fat distribution in Chinese older adults and examine the effects of metabolic syndrome （MS） on abdominal fat distribution by computed tomography （CT）.Methods Chinese elders （aged ≥ 65 years old） undergoing abdominal CT scanning at our hospital from January 2009 to December 2010 were collected through retrospective analysis.A total of 52 healthy normal-weight subjects and gender-specific body mass index （BMI）-matched middleaged adults were selected （28 males,24 females） to compare the difference of abdominal fat during the same period.Visceral fat area （VFA） and subcutaneous fat area （SFA） were measured at the cross-sections of L4 and L5 intervertebral space.Results A total of 390 subjects were enrolled.There were 252 males and 138 females.Total abdominal fat （TAF） was not significantly different in both genders [female （323 ± 122 cm2） vs male （303 ± 141 cm2）,P =0.146].However,females had higher TAF than males after height correction（128 ±49 vs 105 ±49 cm2/m2,P =0.000）.VFA and SFA were higher with higher BMI values across lean,normal weight,overweight and obese groups in both genders.VFA and SFA were not significantly different in both genders among 3 different age groups （〉 65-75,〉 75-85,〉 85 years; P 〉0.05）.Compared with healthy normal weight elders and BMI-matched middle-aged adults,VFA and SFA increased with more components of MS except in only one component group.When the patients were excluded suffering from 2 or more components of MS,VFA was not significantly different between normal weight elders and those with only one component of MS （diabetes/hyperlipidemia/hypertension）.Logistic regression analysis showed VFA was a risk factor for elders with MS（male：OR =1.03,95% CI：1.012-1.047; female：OR=1.06,95%CI：1.026-1.088）.However,SFA and age were not.Conclusions The elder females have more TAF than the elder males while abdominal fat does not increase with age in elders.TAF,VFA and SFA have a highly positively correlation with BMI.Visceral fat,not subcutaneous fat,is a risk factor for elders with MS and it increases with an increment of more than 2 components of MS.