study participants were drawn from the women 's health study ( whs ) , a completed randomized , double - blinded , placebo - controlled trial of low - dose aspirin and vitamin e in the primary prevention of cardiovascular disease ( cvd ) and cancer in women ( 1113 ) .
whs participants were apparently healthy female health care professionals , aged 45 years , who were free of self - reported cvd and cancer at study entry ( 19921995 ) . at the time of enrollment
, women gave written informed consent and completed questionnaires on demographics , anthropometrics , medical history , and lifestyle factors .
they were also asked to provide a baseline blood sample ; 28,345 women did so , and of these , 98.5% ( n = 27,909 ) had nmr measurements . for this study , we excluded women missing other lipids ( n = 33 ) , those with self - reported baseline type 2 diabetes ( n = 770 ) , and those with baseline a1c 6.5% ( n = 270 ) , leaving 26,836 women for analysis
. we also repeated the analyses after excluding 169 women with a1c 6.0 and < 6.5% .
the study was approved by the institutional review board of the brigham and women 's hospital ( boston , ma ) .
edta blood samples were obtained at the time of enrollment into the whs and stored in vapor - phase liquid nitrogen ( 170c ) . in a laboratory certified by the national heart ,
lung , and blood institute / centers for disease control and prevention lipid standardization program , baseline samples were thawed and analyzed for standard lipids .
direct determination of concentrations of total cholesterol , hdl cholesterol , ldl cholesterol , and triglycerides was simultaneously performed on the hitachi 917 analyzer using reagents and calibrators from roche diagnostics ( indianapolis , in ) .
samples for lipoprotein particle analysis by proton nmr spectroscopy were thawed , aliquoted ( 200 l ) , refrozen , and shipped on dry ice to liposcience ( raleigh , nc ) .
particle concentrations of lipoproteins of different sizes were calculated from the measured amplitudes of their spectroscopically distinct lipid methyl group nmr signals ( 7,14 ) .
weighted - average lipoprotein particle sizes are derived from the sum of the diameter of each subclass multiplied by its relative mass percentage based on the amplitude of its methyl nmr signal .
the nmr lipoprotein variables that we examined are those that are provided when ordering an nmr lipoprotein profile for clinical use ( 7 ) .
cvs ranged from 0.4 to 7.1% , except for idlnmr ( 13.1% ) and medium hdlnmr particle concentration ( < 30% ) .
a1c was measured with turbidimetric immunoinhibition using packed erythrocytes ( roche diagnostics ) . high - sensitive c - reactive protein ( hscrp ) was measured using a high - sensitivity immunoturbidimetric assay on the hitachi 917 analyzer ( roche diagnostics ) , using reagents and calibrators from denka seiken .
incident clinical type 2 diabetes in whs participants was ascertained by self - report on annual follow - up questionnaires through march 2008 as previously described ( 15,16 ) .
self - reported cases were then further investigated either by telephone interview with a physician or by a previously validated self - administered supplemental questionnaire that inquired about symptoms , diagnostic diabetes testing , and use of diabetes medications .
the response rate was high , with > 90% response rate to either telephone interview or supplemental questionnaire by women who self - reported diabetes .
glucose screening rates in this population were similar to contemporaneous screening rates in the general population ( 18 ) , with 68.2% of nondiabetic women having reported a screening fasting glucose performed in the prior 3 years .
statistical analyses were performed using stata version 10.1 ( stata , college station , tx ) .
statistical comparisons were obtained from student t tests for continuous variables expressed as means , from wilcoxon rank - sum tests for variables expressed as medians , and  tests for categorical variables .
following guidelines from the department of health and human services ( 19 ) , lipids and lipoproteins were divided into quintiles based on the distribution among women not taking hormone replacement .
cox proportional hazard regression models were used to calculate the hazard ratios ( hrs ) and 95% cis according to these quintiles .
the proportional hazard assumption was tested using schoenfeld residuals and the natural logarithm of follow - up time .
some of the variables did not satisfy the proportionality assumption ; hence , we also divided the follow - up time into the first and second 6 years , finding no substantial differences within each 6-year period .
stronger associations were noted for nmr lipoproteins with diabetes during the first 6 years compared with the second 6 years of follow - up , but the relative magnitude of associations was generally similar within each 6-year period ; therefore , we report the main results for the overall follow - up period unless otherwise specified .
we initially considered two levels of adjustment for 1 ) age , race , and randomized treatment assignment ( minimally adjusted ; model 1 ) ; and 2 ) covariates in model 1 plus smoking status , exercise , education , menopausal status , hormone use , blood pressure , bmi , family history of diabetes , a1c , and hscrp ( nonlipid risk factors ; model 2 ) . to determine the magnitude of association of nmr lipoproteins with diabetes independent of standard lipids
, we additionally adjusted model 2 for triglycerides and hdl and ldl cholesterol and evaluated the association of nmr lipoproteins with diabetes using likelihood ratio  tests .
since lipoprotein particles are metabolically interrelated ( 7,20 ) , nmr lipoproteins were also analyzed in a single model that included the nine nmr lipoprotein subclasses ( two ldlnmr , one idlnmr , three hdlnmr , and three vldlnmr lipoprotein subclasses ) in addition to the nonlipid risk factors , in order to estimate the independent associations of these correlated lipoproteins with diabetes .
based on prior work from this cohort suggesting that nonfasting concentrations of certain lipids may be superior to fasting concentrations for risk prediction ( 21,22 ) , we examined whether fasting status modified the association of nmr lipoproteins with diabetes .
statistical tests for interaction between fasting status and lipoproteins in relation to diabetes were obtained using likelihood ratio tests .
we repeated the analyses after excluding 169 women with a1c 6.0 and < 6.5% , with similar results .
edta blood samples were obtained at the time of enrollment into the whs and stored in vapor - phase liquid nitrogen ( 170c ) . in a laboratory certified by the national heart ,
lung , and blood institute / centers for disease control and prevention lipid standardization program , baseline samples were thawed and analyzed for standard lipids .
direct determination of concentrations of total cholesterol , hdl cholesterol , ldl cholesterol , and triglycerides was simultaneously performed on the hitachi 917 analyzer using reagents and calibrators from roche diagnostics ( indianapolis , in ) .
samples for lipoprotein particle analysis by proton nmr spectroscopy were thawed , aliquoted ( 200 l ) , refrozen , and shipped on dry ice to liposcience ( raleigh , nc ) .
particle concentrations of lipoproteins of different sizes were calculated from the measured amplitudes of their spectroscopically distinct lipid methyl group nmr signals ( 7,14 ) .
weighted - average lipoprotein particle sizes are derived from the sum of the diameter of each subclass multiplied by its relative mass percentage based on the amplitude of its methyl nmr signal .
the nmr lipoprotein variables that we examined are those that are provided when ordering an nmr lipoprotein profile for clinical use ( 7 ) .
cvs ranged from 0.4 to 7.1% , except for idlnmr ( 13.1% ) and medium hdlnmr particle concentration ( < 30% ) .
high - sensitive c - reactive protein ( hscrp ) was measured using a high - sensitivity immunoturbidimetric assay on the hitachi 917 analyzer ( roche diagnostics ) , using reagents and calibrators from denka seiken .
incident clinical type 2 diabetes in whs participants was ascertained by self - report on annual follow - up questionnaires through march 2008 as previously described ( 15,16 ) .
self - reported cases were then further investigated either by telephone interview with a physician or by a previously validated self - administered supplemental questionnaire that inquired about symptoms , diagnostic diabetes testing , and use of diabetes medications .
the response rate was high , with > 90% response rate to either telephone interview or supplemental questionnaire by women who self - reported diabetes .
glucose screening rates in this population were similar to contemporaneous screening rates in the general population ( 18 ) , with 68.2% of nondiabetic women having reported a screening fasting glucose performed in the prior 3 years .
statistical analyses were performed using stata version 10.1 ( stata , college station , tx ) .
statistical comparisons were obtained from student t tests for continuous variables expressed as means , from wilcoxon rank - sum tests for variables expressed as medians , and  tests for categorical variables .
following guidelines from the department of health and human services ( 19 ) , lipids and lipoproteins were divided into quintiles based on the distribution among women not taking hormone replacement .
cox proportional hazard regression models were used to calculate the hazard ratios ( hrs ) and 95% cis according to these quintiles .
the proportional hazard assumption was tested using schoenfeld residuals and the natural logarithm of follow - up time .
some of the variables did not satisfy the proportionality assumption ; hence , we also divided the follow - up time into the first and second 6 years , finding no substantial differences within each 6-year period .
stronger associations were noted for nmr lipoproteins with diabetes during the first 6 years compared with the second 6 years of follow - up , but the relative magnitude of associations was generally similar within each 6-year period ; therefore , we report the main results for the overall follow - up period unless otherwise specified .
we initially considered two levels of adjustment for 1 ) age , race , and randomized treatment assignment ( minimally adjusted ; model 1 ) ; and 2 ) covariates in model 1 plus smoking status , exercise , education , menopausal status , hormone use , blood pressure , bmi , family history of diabetes , a1c , and hscrp ( nonlipid risk factors ; model 2 ) . to determine the magnitude of association of nmr lipoproteins with diabetes independent of standard lipids
, we additionally adjusted model 2 for triglycerides and hdl and ldl cholesterol and evaluated the association of nmr lipoproteins with diabetes using likelihood ratio  tests .
since lipoprotein particles are metabolically interrelated ( 7,20 ) , nmr lipoproteins were also analyzed in a single model that included the nine nmr lipoprotein subclasses ( two ldlnmr , one idlnmr , three hdlnmr , and three vldlnmr lipoprotein subclasses ) in addition to the nonlipid risk factors , in order to estimate the independent associations of these correlated lipoproteins with diabetes .
based on prior work from this cohort suggesting that nonfasting concentrations of certain lipids may be superior to fasting concentrations for risk prediction ( 21,22 ) , we examined whether fasting status modified the association of nmr lipoproteins with diabetes .
statistical tests for interaction between fasting status and lipoproteins in relation to diabetes were obtained using likelihood ratio tests .
we repeated the analyses after excluding 169 women with a1c 6.0 and < 6.5% , with similar results .
during a median follow - up of 13.3 years ( interquartile range 12.313.8 ) , a total of 1,687 incident cases of clinical type 2 diabetes occurred .
table 1 shows the baseline characteristics of participants according to the development of diabetes during follow - up . in comparison with the small differences noted in ldl cholesterol between case subjects and noncase subjects , the nmr - measured concentration of total ldlnmr particles was much higher in case subjects
this resulted from case subjects having more small ldlnmr particles and idlnmr particles but fewer large ldlnmr particles .
case subjects also had significantly less hdlnmr particles ( total ) due to having fewer large hdlnmr particles , despite having more small hdlnmr particles .
vldlnmr particles were higher in case subjects ( both large and small ) . in accordance with these results ,
average particle size in case versus control subjects was smaller for ldlnmr and hdlnmr , and larger for vldlnmr .
baseline characteristics of participants according to incident type 2 diabetes data are median ( interquartile range ) or means  sd , unless otherwise indicated .
* p values were obtained from student t test for continuous variables expressed as means , from wilcoxon rank - sum tests for variables expressed as medians , and  tests for categorical variables .
hrs for diabetes according to quintiles of ldl cholesterol and ldlnmrparticle concentration and size are shown in table 2 . in fully adjusted models , neither
total cholesterol ( data not shown ) nor ldl cholesterol was associated with diabetes ( p for trend 0.53 and 0.64 , respectively ) , but other ldl measures , such as ldlnmr particle concentration and size , were significantly associated with diabetes ( p for trend < 0.001 ) .
association of ldl measures with incident type 2 diabetes data are hr ( 95% ci ) and ( ranges minimum  maximum ) and are given for each quintile .
p for trend obtained from using median quantile as a dependent variable in cox regression models .
model 2 : adjusted for model 1 variables plus smoking , exercise , education , menopausal status , hormone use , blood pressure , bmi , family history of diabetes , a1c , and hscrp .
large ldlnmr particles were inversely associated ( adjusted hr 2.50 [ 95% ci 2.122.95 ] ) for quintile 1 vs. 5 , while small ldlnmr particles were positively associated with diabetes ( 4.04 [ 3.215.09 ] ) for quintile 5 vs. 1 .
the concentration of idlnmr particles , a subclass of ldl particles whose density and size are intermediate between small vldl and large ldl , was positively associated with diabetes , similar in association to small vldlnmr ( shown in table 4 ) but different from the inverse association of large ldlnmr . total ldlnmr particle concentration ( idlnmr + large ldlnmr + small ldlnmr )
was positively associated with diabetes , and the smaller the average ldlnmr particle size the higher the risk .
associations obtained from the minimally adjusted model 1 were generally stronger than model 2 , which had further adjustment for other factors .
hdl cholesterol was inversely associated with diabetes ( table 3 ) , with quintile 1 vs. 5 associated with fourfold increased risk . while total hdlnmr particle concentration was also inversely associated with diabetes ( quintile 1 vs. 5 , adjusted hr 1.20 [ 95% ci 1.031.40 ] ) , it was only large hdlnmr particles that were inversely associated , with quintile 1 ( 4
interestingly , this inverse association noted for large hdlnmr particles was not noted for smaller hdlnmr particles . instead , there was nearly twofold increased risk associated with the highest concentration of small hdlnmr particles .
this was also reflected in hdlnmr average particle size , with smaller hdlnmr size having 4.5-fold higher risk of diabetes .
association of hdl measures with incident type 2 diabetes data are adjusted hr ( 95% ci ) and ( ranges minimum  maximum ) and are given for each quintile .
higher concentrations of triglycerides and triglyceride - rich vldl particles were associated with higher risk of diabetes ( table 4 ) .
large vldlnmr particles , which carry more triglycerides than smaller particles and correlate more with insulin resistance ( 9 ) , had the strongest association of the vldl particles with diabetes , with more than threefold increased risk for quintile 5 vs. 1 .
thus , larger average vldlnmr size correlated with higher risk of diabetes , although not to the same extent as smaller ldlnmr or hdlnmr size , both of which had higher absolute and relative risk .
association of vldl measures with incident type 2 diabetes data are adjusted hr ( 95% ci ) and ( ranges minimum  maximum ) and are given for each quintile .
figure 1 summarizes the adjusted hrs and 95% cis for incident diabetes associated with extreme quintiles of the nmr lipoproteins , standard lipids , and a1c , ranked according to the magnitude of the hrs .
adjusted hrs and 95% cis for quintile 5 vs. 1 , unless otherwise noted , adjusted for nonlipid risk factors ( age , race , randomized treatment assignment , smoking , exercise , education , menopausal status , hormone use , blood pressure , bmi , family history of diabetes , a1c , and hscrp ) .
a1c results were adjusted for age , race , randomized treatment assignment , smoking , exercise , education , menopausal status , hormone use , blood pressure , bmi , family history of diabetes , hscrp , and standard lipids . when we repeated the analyses using continuous variables instead of quintiles , similar results were obtained .
a similar pattern of findings was noted when analyses were stratified by median follow - up time into the first and second 6 years .
overall , stronger associations were noted for a1c and nmr lipoproteins with diabetes during the first 6 years compared with the second 6 years of follow - up , but the relative magnitude of associations was generally similar and significant both early and late in follow - up .
for example , the adjusted hrs ( 95% cis ) for extreme quintile values of ldlnmr , hdlnmr , and vldlnmr size were 6.56 ( 3.9210.99 ) , 7.48 ( 4.0513.83 ) , and 2.87 ( 1.934.26 ) , respectively , early in follow - up ; and 3.74 ( 2.884.85 ) , 4.12 ( 3.075.53 ) , and 2.90 ( 2.263.73 ) , respectively , late in follow - up .
2 ) , noting generally similar results for fasting and nonfasting lipoprotein measurements ( all p for interaction with fasting status > 0.05 ) .
however , there were several borderline significant interactions noted for fasting status with each of small ldlnmr particles , ldlnmr size , and hdlnmr size in relation to diabetes ( p for interaction 0.08 , 0.06 , and 0.05 , respectively ) .
moreover , while the p value for interaction was nonsignificant , nonfasting large vldlnmr particles carried much higher risk for diabetes than fasting measurements .
hrs and 95% cis were adjusted similar to fig . 1 and stratified according to fasting ( black circles ) or nonfasting ( gray diamonds ) status .
when we evaluated all nine nmr - measured lipoprotein particle concentrations in one model that also adjusted for nonlipid risk factors , we found that large and small ldlnmr , large and small hdlnmr , and large vldlnmr remained associated with diabetes .
idlnmr and small vldlnmr particles were no longer significant ( p = 0.38 and 0.62 , respectively ) .
medium hdlnmr and medium vldlnmr particles now showed inverse associations with diabetes . since nmr lipoproteins are correlated with standard lipids , in particular hdl cholesterol and triglycerides , we performed cox models that adjusted for triglycerides and hdl and ldl cholesterol in addition to the nonlipid ( model 2 ) risk factors .
although the associations were attenuated , smaller particle size for ldlnmr and hdlnmr remained significant ( quintile 1 vs. 5 , hr 1.79 , [ 95% ci 1.372.33 ] and 2.39 [ 1.753.28 ] , respectively ; p for trend < 0.001 for both ) , as did larger vldlnmr particle size ( quintile 5 vs. 1 , 2.04 [ 1.632.56 ] ; p for trend < 0.001 ) .
the change in the likelihood ratio  tests was significant for adding either ldlnmr , hdlnmr , or vldlnmr particle size to models that already included standard lipids and nonlipid risk factors ( change in  24.53 , 48.56 , and 59.51 , respectively ; p < 0.0001 for all three ) .
finally , we identified 8,101 women ( number of incident diabetes cases = 132 ) who had normal values of both triglycerides and hdl cholesterol using median values as cut points ( triglycerides < 117 mg / dl and hdl cholesterol > 52 mg / dl ) .
compared with the rest of the cohort , these women were more likely to be hypertensive and hormone users .
we then examined the association of small ldlnmr with incident diabetes in these women after adjusting for nonlipid risk factors ( including hypertension and hormone use ) .
higher concentration of small ldlnmr particles was significantly associated ( p for trend 0.003 ) with incident diabetes , despite that these women had normal levels of triglycerides and hdl cholesterol ( fully adjusted hr for the top versus bottom quintile of small ldlnmr 3.95 [ 95% ci 1.639.55 ] ) .
hrs for diabetes according to quintiles of ldl cholesterol and ldlnmrparticle concentration and size are shown in table 2 . in fully adjusted models , neither
total cholesterol ( data not shown ) nor ldl cholesterol was associated with diabetes ( p for trend 0.53 and 0.64 , respectively ) , but other ldl measures , such as ldlnmr particle concentration and size , were significantly associated with diabetes ( p for trend < 0.001 ) .
association of ldl measures with incident type 2 diabetes data are hr ( 95% ci ) and ( ranges minimum  maximum ) and are given for each quintile .
p for trend obtained from using median quantile as a dependent variable in cox regression models .
model 2 : adjusted for model 1 variables plus smoking , exercise , education , menopausal status , hormone use , blood pressure , bmi , family history of diabetes , a1c , and hscrp .
large ldlnmr particles were inversely associated ( adjusted hr 2.50 [ 95% ci 2.122.95 ] ) for quintile 1 vs. 5 , while small ldlnmr particles were positively associated with diabetes ( 4.04 [ 3.215.09 ] ) for quintile 5 vs. 1 .
the concentration of idlnmr particles , a subclass of ldl particles whose density and size are intermediate between small vldl and large ldl , was positively associated with diabetes , similar in association to small vldlnmr ( shown in table 4 ) but different from the inverse association of large ldlnmr . total ldlnmr particle concentration ( idlnmr + large ldlnmr + small ldlnmr )
was positively associated with diabetes , and the smaller the average ldlnmr particle size the higher the risk . associations obtained from the minimally adjusted model 1 were generally stronger than model 2 , which had further adjustment for other factors .
hdl cholesterol was inversely associated with diabetes ( table 3 ) , with quintile 1 vs. 5 associated with fourfold increased risk . while total hdlnmr particle concentration was also inversely associated with diabetes ( quintile 1 vs. 5 , adjusted hr 1.20 [ 95% ci 1.031.40 ] ) , it was only large hdlnmr particles that were inversely associated , with quintile 1 ( 4 mol / l ) imparting 4.5-fold increased risk of diabetes compared with quintile 5 .
interestingly , this inverse association noted for large hdlnmr particles was not noted for smaller hdlnmr particles .
instead , there was nearly twofold increased risk associated with the highest concentration of small hdlnmr particles .
this was also reflected in hdlnmr average particle size , with smaller hdlnmr size having 4.5-fold higher risk of diabetes .
association of hdl measures with incident type 2 diabetes data are adjusted hr ( 95% ci ) and ( ranges minimum  maximum ) and are given for each quintile .
higher concentrations of triglycerides and triglyceride - rich vldl particles were associated with higher risk of diabetes ( table 4 ) .
large vldlnmr particles , which carry more triglycerides than smaller particles and correlate more with insulin resistance ( 9 ) , had the strongest association of the vldl particles with diabetes , with more than threefold increased risk for quintile 5 vs. 1 .
thus , larger average vldlnmr size correlated with higher risk of diabetes , although not to the same extent as smaller ldlnmr or hdlnmr size , both of which had higher absolute and relative risk .
association of vldl measures with incident type 2 diabetes data are adjusted hr ( 95% ci ) and ( ranges minimum  maximum ) and are given for each quintile .
figure 1 summarizes the adjusted hrs and 95% cis for incident diabetes associated with extreme quintiles of the nmr lipoproteins , standard lipids , and a1c , ranked according to the magnitude of the hrs .
adjusted hrs and 95% cis for quintile 5 vs. 1 , unless otherwise noted , adjusted for nonlipid risk factors ( age , race , randomized treatment assignment , smoking , exercise , education , menopausal status , hormone use , blood pressure , bmi , family history of diabetes , a1c , and hscrp ) .
a1c results were adjusted for age , race , randomized treatment assignment , smoking , exercise , education , menopausal status , hormone use , blood pressure , bmi , family history of diabetes , hscrp , and standard lipids .
when we repeated the analyses using continuous variables instead of quintiles , similar results were obtained .
a similar pattern of findings was noted when analyses were stratified by median follow - up time into the first and second 6 years .
overall , stronger associations were noted for a1c and nmr lipoproteins with diabetes during the first 6 years compared with the second 6 years of follow - up , but the relative magnitude of associations was generally similar and significant both early and late in follow - up .
for example , the adjusted hrs ( 95% cis ) for extreme quintile values of ldlnmr , hdlnmr , and vldlnmr size were 6.56 ( 3.9210.99 ) , 7.48 ( 4.0513.83 ) , and 2.87 ( 1.934.26 ) , respectively , early in follow - up ; and 3.74 ( 2.884.85 ) , 4.12 ( 3.075.53 ) , and 2.90 ( 2.263.73 ) , respectively , late in follow - up .
2 ) , noting generally similar results for fasting and nonfasting lipoprotein measurements ( all p for interaction with fasting status > 0.05 ) .
however , there were several borderline significant interactions noted for fasting status with each of small ldlnmr particles , ldlnmr size , and hdlnmr size in relation to diabetes ( p for interaction 0.08 , 0.06 , and 0.05 , respectively ) .
moreover , while the p value for interaction was nonsignificant , nonfasting large vldlnmr particles carried much higher risk for diabetes than fasting measurements .
hrs and 95% cis were adjusted similar to fig . 1 and stratified according to fasting ( black circles ) or nonfasting ( gray diamonds ) status .
when we evaluated all nine nmr - measured lipoprotein particle concentrations in one model that also adjusted for nonlipid risk factors , we found that large and small ldlnmr , large and small hdlnmr , and large vldlnmr remained associated with diabetes .
idlnmr and small vldlnmr particles were no longer significant ( p = 0.38 and 0.62 , respectively ) .
since nmr lipoproteins are correlated with standard lipids , in particular hdl cholesterol and triglycerides , we performed cox models that adjusted for triglycerides and hdl and ldl cholesterol in addition to the nonlipid ( model 2 ) risk factors .
although the associations were attenuated , smaller particle size for ldlnmr and hdlnmr remained significant ( quintile 1 vs. 5 , hr 1.79 , [ 95% ci 1.372.33 ] and 2.39 [ 1.753.28 ] , respectively ; p for trend < 0.001 for both ) , as did larger vldlnmr particle size ( quintile 5 vs. 1 , 2.04 [ 1.632.56 ] ; p for trend < 0.001 ) .
the change in the likelihood ratio  tests was significant for adding either ldlnmr , hdlnmr , or vldlnmr particle size to models that already included standard lipids and nonlipid risk factors ( change in  24.53 , 48.56 , and 59.51 , respectively ; p < 0.0001 for all three ) .
finally , we identified 8,101 women ( number of incident diabetes cases = 132 ) who had normal values of both triglycerides and hdl cholesterol using median values as cut points ( triglycerides < 117 mg / dl and hdl cholesterol > 52 mg / dl ) . compared with the rest of the cohort ,
we then examined the association of small ldlnmr with incident diabetes in these women after adjusting for nonlipid risk factors ( including hypertension and hormone use ) .
higher concentration of small ldlnmr particles was significantly associated ( p for trend 0.003 ) with incident diabetes , despite that these women had normal levels of triglycerides and hdl cholesterol ( fully adjusted hr for the top versus bottom quintile of small ldlnmr 3.95 [ 95% ci 1.639.55 ] ) .
consistent with prior studies in individuals with insulin resistance , we found that in initially healthy women followed prospectively for incident clinical type 2 diabetes , both triglycerides and hdl cholesterol were independently associated with diabetes but not ldl or total cholesterol .
furthermore , nmr - measured size and concentrations of ldl , hdl , and vldl particles were also associated with diabetes , independent of triglycerides , hdl cholesterol , and other factors .
smaller average size of ldlnmr and hdlnmr particles , as well as the concentration of small ldlnmr and hdlnmr particles , was associated with increased risk , while the concentration of large ldlnmr and hdlnmr particles carried lower risk .
ldlnmr , hdlnmr , and vldlnmr particle size remained associated with diabetes in models that already included standard lipids and nonlipid risk factors , adding incremental risk information beyond that obtained from established risk factors .
a uniting feature of these lipoprotein alterations and their association with type 2 diabetes may be a state of insulin resistance .
the associations we found in this study in relation to the nmr - measured lipoproteins have been previously linked to insulin resistance as measured by the euglycemic clamp ( 9 ) .
garvey et al . ( 9 ) demonstrated a progressive increase in insulin resistance associated with larger vldlnmr size , smaller ldlnmr size , and smaller hdlnmr size , all of which are consistent with our findings in relation to predicting incident type 2 diabetes . in 830 subjects with insulin resistance followed in the insulin resistance atherosclerosis study over a 5-year period , nmr - measured larger vldlnmr size and smaller hdlnmr particles
were independently associated with increased risk of type 2 diabetes ( 14 ) , while ldlnmr size and ldlnmr particles were not significant independent of other risk factors .
factor analysis revealed a single factor that correlated with insulin resistance accounted for nearly half the variance in these lipoprotein measures ( 10 ) .
our study , which was conducted in a large population of healthy women , found independent associations for incident diabetes with baseline ldlnmr size and concentration , with larger ldlnmr particles associated with lower risk and smaller ldlnmr particles associated with higher risk .
moreover , small ldlnmr imparted higher risk of diabetes even in women with normal triglyceride and hdl cholesterol levels .
the inverse association of large ldlnmr particles with type 2 diabetes contrasts with the positive association noted previously in relation to incident cvd in this population of women ( 23 ) .
risk factors for type 2 diabetes may differ from those for cvd ( 24 ) .
for cvd risk , we reported that both small and large ldlnmr particles had similar increase in risk , which contrasts with the inverse association of large ldlnmr , and positive association of small ldlnmr , with risk of diabetes in the current study .
for cvd events , nmr lipoprotein profiles in this cohort of women were comparable but not superior to standard lipids , as recently reported ( 23 ) .
this is in contrast to the current findings for type 2 diabetes , where nmr - measured lipoprotein classification by size provided additive and independent risk information to standard lipids and other risk factors . for hdl particles , the inverse association of hdlnmr size with risk of type 2 diabetes
was also noted previously in relation to risk of cvd in this population of women ( 23 ) . of the hdlnmr particles ,
only large particles were associated with lower risk of diabetes , to a magnitude similar to the association of hdl cholesterol with diabetes , while small particles carried higher risk .
furthermore , adjusting for hdl cholesterol and other risk factors attenuated the association , but larger hdlnmr size remained associated with more than twofold increased risk .
previous studies have found strong inverse relationships between insulin resistance and the large hdlnmr subclass as measured by nmr ( 9,10,14 ) or the corresponding hdl2 subclass as measured by ultracentrifugation ( 25 ) .
for vldl particles , large particles had a greater magnitude of association with diabetes compared with smaller particles , which we explain by large vldl carrying more triglycerides than small vldl and correlating more with the severity of insulin resistance ( 9 ) .
hepatic overproduction of large vldl particles is a key feature of the dyslipoproteinemia of insulin resistance and type 2 diabetes , with evidence for independent regulation of large and small vldl particles ( 26 ) .
in addition , our finding of similar lipoprotein associations with diabetes both early and late in follow - up suggests that these lipoprotein alternations may occur years before the onset of overt hyperglycemia and clinical diagnosis of diabetes , providing a potential opportunity for the early detection and prevention of type 2 diabetes and its complications .
our study is largely limited to caucasian women , these data may not be generalizable to men or other patient groups .
while our study found incremental predictive information for nmr lipoproteins , further studies should be performed in the appropriate patient settings to determine whether a strategy using nmr lipoprotein testing is cost - effective for prevention of type 2 diabetes and related metabolic disorders .
undetected diabetes at study entry is unlikely to have biased our results , since we excluded women with baseline a1c levels 6.5% from our primary sample and found similar results when we excluded those with a1c 6.0% .
in addition , similar results during the first 6 years of follow - up compared with the second 6 years .
we conclude that the size and concentration of nmr - measured ldl , hdl , and vldl particles were associated with clinical type 2 diabetes , independent of other risk factors , particularly chemically measured hdl cholesterol and triglycerides .
the associations of ldlnmr and hdlnmr particles with diabetes differed according to size , with larger particles carrying lower risk and smaller particles carrying higher risk . for vldlnmr
ldlnmr , hdlnmr , and vldlnmr particle size remained significant in models that already included standard lipids and risk factors , adding incremental risk information beyond that obtained from established risk factors for type 2 diabetes .
 objectivediabetic dyslipoproteinemia is characterized by low hdl cholesterol and high triglycerides . 
 we examined the association of lipoprotein particle size and concentration measured by nuclear magnetic resonance ( nmr ) spectroscopy with clinical type 2 diabetes.research design and methodsthis was a prospective study of 26,836 initially healthy women followed for 13 years for incident type 2 diabetes ( n = 1,687 ) . 
 baseline lipids were measured directly and lipoprotein size and concentration by nmr . 
 cox regression models included nonlipid risk factors ( age , race , smoking , exercise , education , menopause , blood pressure , bmi , family history , a1c , and c - reactive protein ) . 
 nmr lipoproteins were also examined after further adjusting for standard lipids.resultsincident diabetes was significantly associated with baseline hdl cholesterol , triglycerides , and nmr - measured size and concentration of ldl , idl , hdl , and vldl particles . 
 the associations of these particles differed substantially by size . 
 small ldlnmr and small hdlnmr were positively associated with diabetes ( quintile 5 vs. 1 [ adjusted hazard ratios and 95% cis ] , 4.04 [ 3.215.09 ] and 1.84 [ 1.542.19 ] , respectively ) . by contrast , large ldlnmr and large hdlnmr were inversely associated ( quintile 1 vs. 5 , 2.50 [ 2.122.95 ] and 4.51 [ 3.685.52 ] , respectively ) . for vldlnmr , large particles imparted higher risk than small particles ( quintile 5 vs. 1 , 3.11 [ 2.354.11 ] and 1.31 [ 1.101.55 ] , respectively ) . 
 lipoprotein particle size remained significant after adjusting for standard lipids and nonlipid factors.conclusionsin this prospective study of women , nmr lipoprotein size and concentrations were associated with incident type 2 diabetes and remained significant after adjustment for established risk factors , including hdl cholesterol and triglycerides . 
RESEARCH DESIGN AND METHODS
Laboratory measurements.
Ascertainment of type 2 diabetes.
Statistical analysis.
RESULTS
LDL measures.
HDL measures.
VLDL measures.
Other analyses.
Incremental value of NMR lipoproteins.
DISCUSSION