the national health interview survey ( nhis ) is an ongoing annual survey designed to collect health - related information on the noninstitutionalized civilian population of the u.s . conducted by the national center for health statistics ( nchs ) , the survey uses a three - stage stratified cluster - probability sampling design . all data are based on respondent self - report . we used data collected from a sample of 359,156 adult participants , aged 18 years , who were interviewed between 1997 and 2008 . we excluded individuals based on any one of the following criteria ( individuals can be excluded for more than one reason ) : missing age at diabetes diagnosis ( n = 1,013 ) ; diabetes diagnosed before the age of 25 years ( n = 2,567 ) ; missing data on height or weight ( n = 15,097 ) ; or outliers for bmi defined as the upper and lower 0.5% of bmi values ( n = 3,351 ) . thus , the final sample comprised 11,056 asian american ( henceforth asian ) and 219,447 non - hispanic white ( henceforth white ) adults . race / ethnicity was categorized using a combination of variables :  race coded to single / multiple race group ,  based on self - reported primary race and  hispanic origin  in 19972005 and the predefined  race / ethnicity recode  in 20062008 . asian subgroups consisted of chinese , filipinos , asian indians , and other asians ( i.e. , korean , japanese , vietnamese , and other asian subgroups ) . in 1997 and 1998 , the nhis included pacific islanders ( i.e. , hawaiian , samoan , guamanian , and other pacific islander subgroups ) as a part of the  other asians  category . however , we were unable to differentiate pacific islanders from other asians based on the public - use dataset . individuals were classified as having diabetes if they gave a positive response to any of the following three questions : 1 )  have you ever been told by a doctor or health professional that you have diabetes or sugar diabetes ?  ; 2)are you now taking insulin ?  ; or 3 )  are you now taking diabetic pills to lower your blood sugar ? those who reported having been told they had borderline diabetes or prediabetes and women who reported having had diabetes only during pregnancy ( gestational diabetes ) were classified as nondiabetic in our analysis . other variables of interests included age , sex , educational attainment , incomes , nation of birth , current smoking and alcohol drinking status , leisure - time physical activity , and bmi . leisure - time physical activity was dichotomized at the level of regular activity recommended by the american heart association ( i.e. , 20 min of vigorous activity three times per week or 30 min of light - to - moderate activity five times per week ) ( 8) . bmi was categorized for whites as underweight / normal weight , overweight , and obese ( bmi < 25 , 25  bmi < 30 , bmi 30 kg / m ) according to national heart , lung , and blood institute guidelines . for asian americans , we first applied the national heart , lung , and blood institute standard and then applied the asian standard ( bmi < 23 , 23  bmi < 27.5 , bmi 27.5 kg / m ) ( 9 ) , which accounts for the generally higher ratio of fat mass to lean body mass in asians versus people of european ancestry at any given level of bmi . we merged 12 years of data and created new design variables that incorporated stratum , primary sampling unit , and sampling weight in order to accommodate different sampling designs between 19972005 and 20062008 ( 7 ) . all analyses accounted for complex sampling designs and weights developed by the nhis to represent the u.s . subsequent analyses were performed by pooling data into four 3-year periods ( 19971999 , 20002002 , 20032005 , and 20062008 ) to enhance robustness . t tests were used to compare continuous variables and  tests were used to compare categorical variables . to examine differences in diabetes prevalence between asians and whites , we calculated age- and sex - adjusted rates using the 2000 u.s . the mean difference of age- and sex - adjusted prevalence in asians versus whites was examined using a linear regression model by period . we compared age- and sex - adjusted bmi in asians overall and in asian subgroups ( chinese , filipinos , asian indians , and other asians ) versus whites by period . we constructed several multivariable logistic regression models to obtain adjusted odds ratios ( ors ) of prevalent type 2 diabetes in asians versus whites . to check for effect modification by sex no interaction was detected ( all p > 0.05 ) ; therefore , only pooled results were presented . nonparametric trend tests across calendar - years were used to conservatively test for secular trends and to account for different sampling designs in 19972005 versus 20062008 ( 10 ) . analyses were performed using stata / se ( version 10.0 ; college station , tx ) . the national health interview survey ( nhis ) is an ongoing annual survey designed to collect health - related information on the noninstitutionalized civilian population of the u.s . conducted by the national center for health statistics ( nchs ) , the survey uses a three - stage stratified cluster - probability sampling design . all data are based on respondent self - report . we used data collected from a sample of 359,156 adult participants , aged 18 years , who were interviewed between 1997 and 2008 . we excluded individuals based on any one of the following criteria ( individuals can be excluded for more than one reason ) : missing age at diabetes diagnosis ( n = 1,013 ) ; diabetes diagnosed before the age of 25 years ( n = 2,567 ) ; missing data on height or weight ( n = 15,097 ) ; or outliers for bmi defined as the upper and lower 0.5% of bmi values ( n = 3,351 ) . thus , the final sample comprised 11,056 asian american ( henceforth asian ) and 219,447 non - hispanic white ( henceforth white ) adults . race / ethnicity was categorized using a combination of variables :  race coded to single / multiple race group ,  based on self - reported primary race and  hispanic origin  in 19972005 and the predefined  race / ethnicity recode  in 20062008 . asian subgroups consisted of chinese , filipinos , asian indians , and other asians ( i.e. , korean , japanese , vietnamese , and other asian subgroups ) . in 1997 and 1998 , the nhis included pacific islanders ( i.e. , hawaiian , samoan , guamanian , and other pacific islander subgroups ) as a part of the  other asians  category . however , we were unable to differentiate pacific islanders from other asians based on the public - use dataset . individuals were classified as having diabetes if they gave a positive response to any of the following three questions : 1 )  have you ever been told by a doctor or health professional that you have diabetes or sugar diabetes ?  ; 2)are you now taking insulin ?  ; or 3 )  are you now taking diabetic pills to lower your blood sugar ? those who reported having been told they had borderline diabetes or prediabetes and women who reported having had diabetes only during pregnancy ( gestational diabetes ) were classified as nondiabetic in our analysis . other variables of interests included age , sex , educational attainment , incomes , nation of birth , current smoking and alcohol drinking status , leisure - time physical activity , and bmi . leisure - time physical activity was dichotomized at the level of regular activity recommended by the american heart association ( i.e. , 20 min of vigorous activity three times per week or 30 min of light - to - moderate activity five times per week ) ( 8) . bmi was categorized for whites as underweight / normal weight , overweight , and obese ( bmi < 25 , 25  bmi < 30 , bmi 30 kg / m ) according to national heart , lung , and blood institute guidelines . for asian americans , we first applied the national heart , lung , and blood institute standard and then applied the asian standard ( bmi < 23 , 23  bmi < 27.5 , bmi 27.5 kg / m ) ( 9 ) , which accounts for the generally higher ratio of fat mass to lean body mass in asians versus people of european ancestry at any given level of bmi . we merged 12 years of data and created new design variables that incorporated stratum , primary sampling unit , and sampling weight in order to accommodate different sampling designs between 19972005 and 20062008 ( 7 ) . all analyses accounted for complex sampling designs and weights developed by the nhis to represent the u.s . subsequent analyses were performed by pooling data into four 3-year periods ( 19971999 , 20002002 , 20032005 , and 20062008 ) to enhance robustness . t tests were used to compare continuous variables and  tests were used to compare categorical variables . to examine differences in diabetes prevalence between asians and whites , we calculated age- and sex - adjusted rates using the 2000 u.s . the mean difference of age- and sex - adjusted prevalence in asians versus whites was examined using a linear regression model by period . we compared age- and sex - adjusted bmi in asians overall and in asian subgroups ( chinese , filipinos , asian indians , and other asians ) versus whites by period . we constructed several multivariable logistic regression models to obtain adjusted odds ratios ( ors ) of prevalent type 2 diabetes in asians versus whites . to check for effect modification by sex no interaction was detected ( all p > 0.05 ) ; therefore , only pooled results were presented . nonparametric trend tests across calendar - years were used to conservatively test for secular trends and to account for different sampling designs in 19972005 versus 20062008 ( 10 ) . analyses were performed using stata / se ( version 10.0 ; college station , tx ) . table 1 presents the characteristics of 230,503 study participants by race / ethnicity and period . over 12 years , the weighted proportion of asians in the nhis sample increased from 3.1 to 4.6% , and 12,943 adults reported having physician - diagnosed type 2 diabetes ( 554 asians and 12,389 whites ) . compared with whites , , had higher educational attainment and higher incomes , and were less likely to be current smokers or drinkers ( all p < 0.05 , except for income in the period of 20002002 : p = 0.15 ) . during the study period , asians were consistently less likely than whites to report engaging in american heart association  recommended levels of physical activity ( 2630% vs. 3334% ; all p < 0.001 ) . characteristics of asian and white adults in the u.s . , nhis 19972008 * all characteristics of asians are significantly different from those in whites ( p < 0.05 ) , except the proportion of female subjects in 19971999 , 20032005 , and 20062008 and the proportion of higher education in 20002002 . * data are weighted means or proportions , ses for mean age were < 1 , for mean bmi were < 0.2 , and for other variables were < 0.03 . some college or college graduate . previous - year individuals total incomes including hourly wages , salaries , tips , and commissions . ||percent met the recommended leisure - time physical activities : 20 min of vigorous activity three times per week or 30 min of light to moderate activity five times per week . * * 23  bmi < 27.5 kg / m for asians , 25  bmi < 30 kg / m for whites . as expected , asians had lower bmi than whites ( mean 24 vs. 2627 kg / m ) and were less likely to be overweight ( 2430 vs. 3536% ) or obese ( 68 vs. 1925% ) according to western standards ( all p < 0.0001 ) . after applying modified adiposity criteria for asians , their excess prevalence of obesity persisted ( 1317 vs. 1925% ; p < 0.0001 ) , but the disparity in overweight was reversed ( 3942 vs. 3536% ) . there was no significant secular trend in any covariate shown in table 1 in either asians or whites using data in 19971999 as the reference ( all p > 0.05 ; data not shown ) . figure 1 displays secular trends in type 2 diabetes and bmi after adjusting for age and sex . prevalent type 2 diabetes was substantially more common in asians than in whites throughout the interval ( 4.77.3 vs. 3.85.6% ; all p < 0.05 ) , and both groups showed significant upward trends in prevalence . on the contrary there were upward trends in bmi in both groups ( p values for trend : asians = 0.003 and whites = 0.001 ) , and the asian  white bmi difference grew over time , especially in the obese tail of the distribution ( age- and sex - adjusted prevalence of obesity in asians versus whites : 1317 vs. 1925% ; all p < 0.05 ) . lowess - smoothed line curves represent age- and sex - standardized prevalence rates of type 2 diabetes in 19972008 , after accounting for sampling weight . the solid line represents asians ( a ) and the dotted line represents whites ( w ) . box - plot reveals age- and sex - standardized bmi in each period ( 19971999 , 20002002 , 20032005 , and 20062008 ) and draw at the midpoint of each period . filipinos and asian indians had the highest bmis over the interval , and chinese subjects had the lowest . significant upward trends were observed only in chinese and filipinos ( p = 0.042 and 0.02 , respectively ) . in 20062008 , the age- and sex - adjusted prevalence of overweight plus obesity using the asian standard was 71 , 69 , 57 , and 47% in filipinos , asian indians , other asians , and chinese , respectively . each box plot represents age- and sex - standardized bmi , and colors stand for each period by race / ethnicities . p for trends : whites = 0.001 , chinese = 0.042 , other asians = 0.32 , asian indian = 0.26 , and filipinos = 0.002 . finally , we calculated the adjusted or of prevalent type 2 diabetes in asians versus whites over the interval ( table 2 ) . after adjusting for age and sex , the odds of prevalent type additional adjustment for bmi as a categorical variable , using the asian standard , strengthened these associations ( p < 0.05 in all time intervals ) . in the fully adjusted model , the odds of prevalent type 2 diabetes in asians remained consistently greater than those in whites throughout the period ( or range 1.31.5 , all p < 0.05 , except for 20002002 , or 1.3 [ 95% ci 0.91.8 ] ) . adjusted ors of prevalent type 2 diabetes in asians versus whites , nhis 19972008 numbers data are or ( 95% ci ) . model 2 : model 1 + bmi categories ( underweight / normal weight : bmi < 23 kg / m for asians and bmi < kg / m for asians and 25  bmi < 30 kg / m for whites ; obese : bmi 27.5 kg / m for asians and bmi 30 kg / m for whites ) . model 3 : model 2 + education , incomes , nation of birth , current smoking and alcohol drinking status , and leisure - time physical activity . furthermore , we calculated the adjusted ors of prevalent type 2 diabetes in asian subgroups versus whites over the study period . asian indians had the highest odds of prevalent type 2 diabetes , followed by filipinos , other asians , and chinese . these observations were stable over the study period ( p for trend > 0.05 ) . ors ( 95% cis ) of prevalent type 2 diabetes in asian subgroups versus whites in the fully adjusted model ( controlled for age , sex , bmi categories , education , incomes , nation of birth , current smoking and alcohol drinking status , and leisure - time physical activity ) . figure 1 displays secular trends in type 2 diabetes and bmi after adjusting for age and sex . prevalent type 2 diabetes was substantially more common in asians than in whites throughout the interval ( 4.77.3 vs. 3.85.6% ; all p < 0.05 ) , and both groups showed significant upward trends in prevalence . on the contrary , bmi was substantially lower in asians than in whites throughout the interval . there were upward trends in bmi in both groups ( p values for trend : asians = 0.003 and whites = 0.001 ) , and the asian  white bmi difference grew over time , especially in the obese tail of the distribution ( age- and sex - adjusted prevalence of obesity in asians versus whites : 1317 vs. 1925% ; all p < 0.05 ) . lowess - smoothed line curves represent age- and sex - standardized prevalence rates of type 2 diabetes in 19972008 , after accounting for sampling weight . the solid line represents asians ( a ) and the dotted line represents whites ( w ) . box - plot reveals age- and sex - standardized bmi in each period ( 19971999 , 20002002 , 20032005 , and 20062008 ) and draw at the midpoint of each period . filipinos and asian indians had the highest bmis over the interval , and chinese subjects had the lowest . significant upward trends were observed only in chinese and filipinos ( p = 0.042 and 0.02 , respectively ) . in 20062008 , the age- and sex - adjusted prevalence of overweight plus obesity using the asian standard was 71 , 69 , 57 , and 47% in filipinos , asian indians , other asians , and chinese , respectively . each box plot represents age- and sex - standardized bmi , and colors stand for each period by race / ethnicities . p for trends : whites = 0.001 , chinese = 0.042 , other asians = 0.32 , asian indian = 0.26 , and filipinos = 0.002 . finally , we calculated the adjusted or of prevalent type 2 diabetes in asians versus whites over the interval ( table 2 ) . after adjusting for age and sex , the odds of prevalent type 2 diabetes in asians generally were 2040% greater than in their white counterparts . additional adjustment for bmi as a categorical variable , using the asian standard , strengthened these associations ( p < 0.05 in all time intervals ) . in the fully adjusted model , the odds of prevalent type 2 diabetes in asians remained consistently greater than those in whites throughout the period ( or range 1.31.5 , all p < 0.05 , except for 20002002 , or 1.3 [ 95% ci 0.91.8 ] ) . adjusted ors of prevalent type 2 diabetes in asians versus whites , nhis 19972008 numbers data are or ( 95% ci ) . model 2 : model 1 + bmi categories ( underweight / normal weight : bmi < 23 kg / m for asians and bmi < kg / m for asians and 25  bmi < 30 kg / m for whites ; obese : bmi 27.5 kg / m for asians and bmi 30 kg / m for whites ) . model 3 : model 2 + education , incomes , nation of birth , current smoking and alcohol drinking status , and leisure - time physical activity . furthermore , we calculated the adjusted ors of prevalent type 2 diabetes in asian subgroups versus whites over the study period . asian indians had the highest odds of prevalent type 2 diabetes , followed by filipinos , other asians , and chinese . these observations were stable over the study period ( p for trend > 0.05 ) . ors ( 95% cis ) of prevalent type 2 diabetes in asian subgroups versus whites in the fully adjusted model ( controlled for age , sex , bmi categories , education , incomes , nation of birth , current smoking and alcohol drinking status , and leisure - time physical activity ) . although asian americans were more likely to attend college , were less likely to smoke , were less likely to drink , and had lower bmi , asian americans are ~30% more likely to have type 2 diabetes than their white counterparts . second , both bmi and diabetes prevalence are rising in all asian subgroups , especially filipinos . third , although the or of diabetes in asians versus whites has remained relatively stable over the past decade , the steady climb in diabetes prevalence in both groups coincides with a widening gap in terms of absolute diabetes prevalence . we noted that compared with whites , asian americans were more likely to be overweight but less likely to be obese , after applying the modified asian criteria . nonetheless , we should interpret the observation with caution because the real overweight / obesity cut points are likely to vary for different asian populations ( 11 ) . our results are consistent with previous studies of diabetes in asian americans . using 3-year ( 20042006 ) pooled nhis data , barnes et al . ( 5 ) reported an age - standardized diabetes prevalence of 7.5% in whites versus 6.4% in asian americans . in a study using the 2001 u.s . behavioral risk factor surveillance system data , mcneely and boyko ( 6 ) found that type 2 diabetes was 60% more likely in asian americans than in whites ( or 1.6 [ 95% ci 1.12.2 ] ) . most recently , two studies used nhis data to compare the risk of type 2 diabetes in subgroups of asians ( i.e. , chinese , filipinos , asian indians , and other asians ) to whites . ( 12 ) showed that the risk in asians was higher than whites across all asian subgroups ( or range 1.33.5 ) . ( 13 ) likewise observed that asian indians and filipinos were more likely to have type 2 diabetes than whites ( or range 1.12.3 ) after multiple adjustment . in this study , we further investigated trends in diabetes prevalence over time and in relation to patterns of change in bmi . we found that although the ors of diabetes in asians versus whites has remained quite stable over the past decade , obesity and diabetes prevalence in both race groups increased concurrently . first , asians appear to be more genetically predisposed to develop type 2 diabetes compared with their white counterparts ( 1416 ) . second , chronic stress related to immigration acculturation could contribute to visceral adiposity and insulin resistance ( 16 ) . finally , asians are known to have higher visceral fat accumulation compared with whites at any given level of bmi ( 17 ) . ( 18 ) reported that for the same bmi , the body fat percentage in asian indians was higher than whites as well as other asian populations . likewise , for the same waist circumference , filipino women had a higher visceral fat and visceral - to - subcutaneous abdominal fat ratio than white women ( 19 ) . those unfavorable fat distributions may contribute to the higher risk of diabetes in those two asian populations ( 9 ) . physical inactivity is a well - established risk factor for incident type 2 diabetes independent from adiposity ( 20 ) . although physical inactivity did not completely explain the excess risk of type 2 diabetes in asian americans in our analysis , it is known to be a common diabetes risk factor in asian americans . for example , kandula et al . ( 21 ) observed that asian immigrants were 50% less likely to meet the recommended physical activity level than u.s .- born non - asians , based on the 2001 california health interview survey . physical inactivity is of particular interest from a public health perspective because it is more readily modifiable than adiposity . strengths of our study include a very large , nationally representative sample with uniform ascertainment of diabetes and related variables over a time interval during which the population of asian americans and the prevalence of type 2 diabetes have both climbed dramatically . first , the secular patterns we observed were based entirely on cross - sectional data ; therefore , these results may have been influenced by survival and/or selection bias related to immigration that limited the inferences about racial disparities in incident diabetes risk . second , the nhis is based exclusively on self - reported data . because participants were asked to select a primary race , possible misclassification in mixed - race participants may underestimate the associations . it is also possible that the disparities we observed arose in part from racial differences in physician diagnosis and/or patient recall of diabetes . use of self - reported height and weight may lead to underestimation of bmi , but we know of no evidence that the degree of underestimation differs systematically in asian americans versus whites ( 22 ) . finally , information on other diabetes risk factors , such as dietary intake and family history of diabetes , are not available in the nhis . the main implication of our study is that type 2 diabetes is a growing public health problem for asian americans that requires urgent attention . although greater genetic predisposition no doubt plays a role , future research should identify modifiable risk factors that underlie the asian  white disparity in diabetes prevalence as a step toward the development of culturally tailored prevention strategies .
objectiveto examine trends in the prevalence of type 2 diabetes and related conditions in asian americans compared with non - hispanic whites.research design and methodswe analyzed data from the national health interview survey ( nhis ) from 1997 to 2008 to construct a nationally representative sample of 230,503 u.s . 
 adults aged 18 years . of these adults , 
 11,056 identified themselves as asian americans and 219,447 as non - hispanic whites.resultsthe age- and sex - adjusted prevalence of type 2 diabetes was higher in asian americans than in whites throughout the study period ( 4.38.2% vs. 3.86.0% ) , and there was a significant upward trend in both ethnic groups ( p < 0.01 ) . 
 bmi also was increased in both groups , but age- and sex - adjusted bmi was consistently lower in asian americans . in fully adjusted logistic regression models , asian americans remained 3050% more likely to have diabetes than their white counterparts . 
 in addition , asian indians had the highest odds of prevalent type 2 diabetes , followed by filipinos , other asians , and chinese.conclusionscompared with their white counterparts , asian americans have a significantly higher risk for type 2 diabetes , despite having substantially lower bmi . 
 additional investigation of this disparity is warranted , with the aim of tailoring optimal diabetes prevention strategies to asian americans .