the prevalence of diabetes is high and increasing over the world . especially in developing countries , the total number of adults with diabetes will increase 69% from 2010 to 2030 . diabetes mellitus ( dm ) prevention is recognized as a major public health priority in developing nations . therefore , there is a great interest in identifying individuals at high risk of developing diabetes . currently , it is well known that risk scoring models and anthropometric measures could predict future incidence of dm [ 28 ] . for example , the finnish diabetes risk score   and the framingham offspring study simple clinical model , based on more than 10 years follow - up , have been used as a tool to predict the risk for diabetes . however , it seems that the predictive value of risk scoring models is time - varying . stern et al .   published a clinical model to predict diabetes risk using fasting glucose and other routine clinical data , including age , sex , and ethnicity . this clinical model predicted 7.5-year incidence of diabetes better than the 2  h glucose load during oral glucose tolerance test in mexican - american and non - hispanic white participants from san antonio heart study . had found that the validity of this clinical model to predict incident diabetes was inconsistent between 5 - 6 years and 10 years in japanese americans aged less than 55 . on the other hand , we do not know whether this phenomenon also exits in anthropometric measures , especially in chinese han nationality . to our knowledge , the duration of studies using anthropometric measures for predicting diabetes in chinese han nationality was mostly less than 15 years , and a little literature had been reported for more than 15 years . therefore , we compared the predictive ability of anthropometric measures for predicting dm incidence based on a 15-year prospective study in chinese adults . the study sample population was obtained from a chinese multi - provincial cohort study ( cmcs ) approved by the beijing institute of heart , lung and blood vessel diseases for the entire duration , a nationwide , multicenter prospective cohort study on cvd risk factors in the chinese . a total of 30121 chinese subjects aged 3564 and free of cvd at commencement was included by a multistage sampling method in which detailed information regarding the methodology had been previously reported [ 1315 ] . of these , 27003 subjects were recruited from 16 centers in 11 chinese provinces between 1992 and 1993 . at one of the centers ( sichuan , china ) , 711 individuals in an urban community located in chengdu , sichuan province , china , were included . the cohort also accepted a health examination in 2007 for a study supported by megaprojects of science research for the 11th five - year plan ( trends in the incidence of metabolic syndrome and integrated control in china ) with the same methods . twenty - four individuals were excluded from this analysis for being diagnosed with diabetes in 1992 . therefore , 687 individuals with complete data were available ( figure 1 ) . in 1992 , medicine doctors and nurses did a survey of cardiovascular disease ( cvd ) risk factors according to the multinational monitoring of trends and determinants in cardiovascular disease ( monica ) protocol . standardized questionnaire , physical examination , and laboratory tests were included in this survey . a standardized questionnaire was used for collecting information on subjects ' demographic characteristics , cvd risk factors , such as smoking status , alcohol consumption levels , physical activity , and family history of cvd . anthropometric measurements included height , weight , wc , and hip circumference measured while the patients were lightly clothed and without shoes after approximately 12  h of overnight fasting . measurements were conducted using a calibrated weighing scale , wall - mounted stadiometer , and tape measure . the results were recorded to the nearest 0.2  kg , 1  cm , and 0.5  cm . waist circumference ( wc ) was taken with the subject in a standing position , at the level midway between the lateral rib margin and the iliac crest . bmi was calculated using the following formula : weight / height ( kg / m ) . whpr was calculated as wc divided by hip circumference , and whtr as wc divided by height . blood pressure ( bp ) was measured in the right arm with subjects in a sitting position using a regular mercury sphygmomanometer after resting for 15 minutes . the three consecutive blood pressure readings were used for mean value of the bp . fasting plasma glucose ( fpg ) , fasting serum total cholesterol ( tc ) , low - density lipoprotein cholesterol ( ldl - c ) , high - density lipoprotein cholesterol ( hdl - c ) , and triglyceride ( tg ) were included . biochemistry parameters were measured at the laboratory of west china hospital ( chengdu , china ) . tc , tg , and fpg were all determined using the enzymatic method , while hdl - c was measured using the phosphotungstic acid / magnesium chloride precipitation method . the level of non - hdl cholesterol was calculated by subtracting hdl cholesterol from total cholesterol determined . the concentration of ldl - c was estimated using the friedewald formula , and very low - density lipoprotein cholesterol was calculated by subtracting serum ldl - c and hdl - c from tc [ 13 , 14 , 17 ] . this survey was approved by the ministry of health of china as well as the ethics committee of west china hospital of sichuan university . the study protocol conforms to the ethical guidelines of the 1975 declaration of helsinki as reflected in a priori approval by the institution 's human research committee . hypertension was defined as having systolic blood pressure ( sbp ) of at least 140  mm  hg and/or diastolic blood pressure ( dbp ) of at least 90  mm  hg and/or currently taking antihypertensive medications . diabetes mellitus was defined as one of the following at follow - up assessment : ( 1 ) fasting plasma glucose  7.0 mmol / l , ( 2 ) a positive response to the question , has a doctor ever told you that you have diabetes ?  , or ( 3 ) current use of insulin or oral hypoglycemic agents . alcohol intake was defined as average intake of alcohol of at least 50  g / d . physical activity was defined as exercise one or more times per week , at least 20 minutes for each time [ 15 , 17 , 18 ] . continuous variables were expressed as the mean  sd or median ( interquartile range ) as appropriate . differences of baseline characteristics between participants with and without diabetes were tested by independent t - test for normally distributed variables and by the nonparametric mann - whitney or wilcoxon test for skewed variables . this study population was stratified into quartiles of bmi , wc , whpr , and whtr . to assess the effects of baseline anthropometric measures on the new onset of diabetes , cox 's proportional hazards regression models were used to estimate the hazard ratios ( hrs ) of them , and the discriminatory power of anthropometric measures for diabetes was assessed by the area under the receiver operating curve ( aroc ) . the hazard ratios ( hrs ) were computed for quartiles 2 , 3 , and 4 as compared with the lowest quartile in different cox 's proportional hazards regression models . covariates including age , systolic blood pressure ( sbp ) , tg , hdl - c , and fpg were fitted as continuous variables in the multivariate analyses and alcohol intake , smoking , regular physical exercise , and family history of diabetes were fitted as categorical variables . the point represented the largest sum of sensitivity and specificity on the receiver operating curve ( roc ) was chosen to obtain these four measurements in predicting diabetes . 687 eligible subjects studied at baseline completed the 7 - 8 years and the 15-year follow - up . the incidence of diabetes was 2.8% ( n = 19 ) at 8 years and 10.8% ( n = 74 ) at 15 year . the percentage of self - reported history was 67.6% ( 50/74 ) during the 15-year follow - up . among the self - reported participants , 37 individuals were on antidiabetic drugs . for the other 24 diagnosed dm individuals , the average fpg was 9.5  mmol / l . mmol / l and the maximum and minimum were 16.2  mmol / l and 7.1  mmol / l , respectively . characteristics of participants at baseline were shown in table 1.compared with subsequent nondiabetic subjects , the demographic data in 1992 showed that subsequent diabetic subjects had a higher bmi , wc , hip circumference , whpr , whtr , fasting plasma glucose , and triglycerides at 7 - 8 years and 15-year follow - up ( all p < 0.001 , table 1 ) . the univariate cox 's proportional hazards regression analysis presented that these anthropometric measures ( bmi , wc , whpr , and whtr ) could statistically increase the risk for the new onset of diabetes with a 15-year follow - up ( table 2 ) . in the multivariate cox 's proportional hazards regression models , all measurements were significantly associated with risk of diabetes after adjustment for potential risk factors including age , sex , alcohol intake , smoking , regular physical exercise , family history of diabetes , and fpg . after further adjustment for sbp , tg , and hdl , the associations were reduced , but remained to be significant ( table 2 ) . figure 2 showed the cumulative incidence of dm in different anthropometric variables groups in multivariate cox - regression in model 2 . the areas under the roc curves were 0.668 ( 95% ci : 0.6310.703 ) for bmi , 0.781 ( 95% ci : 0.7480.811 ) for wc , 0.769 ( 0.7360.800 ) for whpr , and 0.768 ( 0.7340.799 ) for whtr at 7 - 8-year follow - up , respectively ( all p < 0.05 ) , while 0.668 ( 95% ci : 0.6010.734 ) for bmi , 0.701 ( 95% ci : 0.6410.760 ) for wc , 0.691 ( 95% ci : 0.6370.748 ) for whpr , and 0.715 ( 95% ci : 0.6570.774 ) for whtr ( all p < 0.05 , table 3 ) at 15-year follow - up . table 3 indicated that wc , whpr , and whtr were better than bmi for predicting incident diabetes at 7 - 8 years in chinese han nationality population from chengdu community . however , the four anthropometric measurements had no significant difference for predicting 15-year incidence of diabetes . the goal of the study was to assess whether bmi , wc , whpr , and whtr could predict future diabetes on the basis of data collected from a general chinese group during 15-year follow - up and to assess whether the validity of anthropometric measures to predict incident diabetes were stable as time goes by , especially in chinese han nationality . after adjusting for potential confounders , our findings showed that both general obesity measures ( bmi ) and central obesity measures ( wc , whpr , whtr ) could predict future diabetes in a chinese population after a long follow up . on the other hand , wc , whpr , and whtr were better than bmi for predicting incident diabetes at 7 - 8 years in chinese han nationality population from chengdu community . the four anthropometric measurements had not significant difference for predicting 15-year incidence of diabetes . in recent years , some studies showed a more close association between diabetes and central obesity measures than bmi [ 1923 ] , whereas other studies showed no significant differences between the obesity measures [ 2426 ] . meanwhile , meta - analysis studies also showed inconsistent results [ 27 , 28 ] . however , we reviewed literatures of previous prospective studies comparing bmi , wc , whpr , and whtr for predicting incidence of diabetes and found that many studies reporting a difference between the obesity measures did not use appropriate study statistical methods or that it did not investigate all indicators with data on only 1 or more of the 4 indicators ( i.e. , bmi , wc , and whpr ) with regard to the association with diabetes risk . more importantly , length of the follow - up periods might influence study results [ 2946 ] ( see supplementary table 1 available online at http://dx.doi.org/10.1155/2013/239376 ) . firstly , we compared the predictive ability of the four anthropometric measures for predicting dm incidence based on a 15-year prospective study in chinese adults . similar to our findings , in 610 years and 1115 years longitudinal follow - up groups in supplementary table 1 , the majority of trials had shown no significant difference between obesity measures . thought that different methods of collecting numbers of onset diabetes and obesity measures might result in this result . diabetes incidence was self - reported and anthropometric indicators were self - measured by the participants in the two studies . but , investigators from the san antonio heart study   and epic - potsdam study , with similar methods , had demonstrated higher risk with wc or whpr than bmi in predicting diabetes incidence . our findings revealed that wc , whpr , and whtr were better than bmi for predicting incident diabetes at 7 - 8 years in the same population . however , the four indictors did not have a significant difference in our study at 15 years . a study reported that over 10 years , total fat mass and fat mass except subcutaneous fat increased , whereas body weight did not change . it was possible that many subjects tend to become abdominally obese rather than become totally obese during follow - up , and the impact of baseline body fat distribution on diabetes risk was weakened with lengthening of the follow - up period . on the other hand , racial and regional differences in the association between obesity and the risk for diabetes might also have influenced the results . although the prevalence of obesity is much lower in asia than in western countries , the prevalence of diabetes is similar between the two regions , and diabetes occurs in asians who are less obese . therefore , we reviewed studies that compared anthropometric measures in predicting risk of diabetes in chinese mainland [ 5053 ] ( supplementary table 2 ) . there might be a greater bias risk in data collection ( i.e. , potential detection bias ) , and the cross - sectional data showed only the association with present risk factor conditions but did not directly predict the future risk of dm . a long follow - up time was to avoid not only insufficiency of new onset diabetes cases in short - term follow - up that underestimated the predictive power of the measurement indexes but also potential detection bias in cross - sectional studies that exaggerate the statistical power of the indexes . taking into account the sample size , sex , and region , we can not extend our findings to general population . but we need to know that the length of follow - up period is a factor that can not be ignored . another advantage was that a standardized protocol was used and all anthropometric variables were collected using direct measurement by trained doctors and nurses rather than self - report . this limited the study , and we could not analyze the association between anthropometric measures with diabetes risk classified by gender . the results of our study may have limited statistical power ; but we still can get some clues . the second was the way to diagnose diabetes mellitus . during the investigation , taken into account the financing and feasibility , we had diagnosed diabetes by measuring fasting plasma glucose and patient self - reports rather than oral glucose tolerance test means . some individuals would have developed dm that was not detectable by changes in fasting glucose alone or by clinical history , leading to the underestimation of the experimental results . , our findings showed that anthropometric measures could predict diabetes with a long - time follow - up . however , the validity of anthropometric measures to predict incident diabetes may change with time . future researches may be warranted to assess whether this phenomenon still exists in mainland china with different duration of follow - up time in a large population .
objective . to examine whether anthropometric measures could predict diabetes incidence in a chinese population during a 15-year follow - up . 
 design and methods . 
 the data were collected in 1992 and then again in 2007 from the same group of 687 individuals . 
 waist circumference , body mass index , waist to hip ratio , and waist to height ratio were collected based on a standard protocol . to assess the effects of baseline anthropometric measures on the new onset of diabetes , cox 's proportional hazards 
 regression models were used to estimate the hazard ratios of them , and the discriminatory power of anthropometric measures for diabetes was assessed by the area under the receiver operating curve ( aroc ) . results . 
 seventy - four individuals were diagnosed with diabetes during a 15-year follow - up period ( incidence : 10.8% ) . 
 these anthropometric measures also predicted future diabetes during a long follow - up ( p < 0.001 ) . at 7 - 8 years , the aroc of central obesity measures ( wc , whpr , whtr ) were higher than that of general obesity measures ( bmi ) ( p < 0.05 ) . 
 but , there were no significant differences among the four anthropometric measurements at 15 years . 
 conclusions . 
 these anthropometric measures could still predict diabetes with a long time follow - up . 
 however , the validity of anthropometric measures to predict incident diabetes may change with time .