Low high-density lipoprotein cholesterol level is a significant risk factor for development of type 2 diabetes: Data from the Hawaii-Los Angeles-Hiroshima study

Association of HindIII Polymorphism of the Lipoprotein Lipase (LPL) Gene (rs320) and Plasma Metabolic Parameters in a Nigerian Population

Genetic variations in the lipoprotein lipase (LPL) gene including the HindIII polymorphism (rs320) have been reported to modify fat metabolism, adiposity, and body weight. However, little attention has been given to the African population. The present study aimed to investigate the relationship between the rs320 gene polymorphism and a number of metabolic and anthropometric parameters in a sample of the Nigerian population. We recruited 236 participants for the study. The participants were required to sign informed consent forms after which information related to their calorie intake and utilization as well as anthropometric measurements were recorded. Plasma metabolic parameters were subsequently determined using an autoanalyzer. Genotyping for HindIII polymorphism was performed using the PCR-RFLP method. The frequencies (n) of T and G alleles were 0.841 (397) and 0.158 (75), while the frequencies (n) of TT, TG, and GG were 0.691(163), 0.301(71), and 0.01(2), respectively. The population was not in Hardy-Weinberg equilibrium (χ2 = 3.717, df = 1, p = 0.841). The anthropometric parameters, the fasting blood glucose, and low-density lipoprotein cholesterol showed no association with the alleles, while plasma high-density lipoprotein cholesterol and total cholesterol were significantly higher among the G allele carriers. However, triglyceride and total protein were significantly higher among the non-G allele carriers. The LPL HindIII gene polymorphism is associated with changes in plasma lipid profile in a sample of the Nigerian population.

Association between nontraditional lipid parameters and the risk of type 2 diabetes and prediabetes in patients with nonalcoholic fatty liver disease: from the national health and nutrition examination survey 2017-2020

Background

Nonalcoholic fatty liver disease (NAFLD) is a prevalent metabolic disorder strongly linked to type 2 diabetes mellitus (T2DM). Understanding the predictive value of lipid parameters in identifying abnormal glucose metabolism in NAFLD patients is crucial for early intervention.

Methods

This study analyzed data from the National Health and Nutrition Examination Survey(NHANES) database (2017-2020) involving 1066 NAFLD patients. Participants were categorized into three groups: T2DM (n=414), prediabetes mellitus (pre-DM) (n=507), and normoglycemia (NG) (n=145). Traditional lipid parameters [triglycerides (TG) and high-density lipoprotein cholesterol (HDL-C)] and nontraditional lipid parameters [atherogenic index of plasma (AIP), residual cholesterol (RC), and non-high-density lipoprotein cholesterol (non-HDL-C)] were evaluated for their association with T2DM and pre-DM.

Results

Elevated TG levels were significantly associated with an increased risk of T2DM and pre-DM, whereas high HDL-C demonstrated a protective effect. Among nontraditional lipid parameters, increased AIP and RC were most strongly associated with T2DM risk, while high non-HDL-C was best associated with the development of pre-DM. Stratified analyses revealed that these associations were stronger in younger, non-obese, smoking, and female NAFLD patients.

Conclusion

Nontraditional lipid parameters, particularly AIP and RC, show superior predictive value over traditional lipid parameters in identifying abnormal glucose metabolism in NAFLD patients. Incorporating these novel biomarkers into clinical practice could enhance early detection and prevention strategies for T2DM and pre-DM in this high-risk population.

A suggested shared aetiology of dementia - a colocalization study

Identification of shared causal genes between dementia and its related clinical outcomes can help understand shared aetiology and multimorbidity surrounding dementia. We performed the HyPrColoc colocalization analysis to detect possible shared causal genes between dementia or Alzheimer's disease (AD) and 5 selected traits: stroke, diabetes, atherosclerosis, cholesterol level, and alcohol consumption within 601 dementia or AD associated genetic regions using summary results of the UK Biobank genome-wide association studies. Functional analysis was performed on the candidate causal genes to explore potential biological pathways. Rs150562240 in the LPIN3 gene was identified as a candidate shared causal variant across dementia, AD and atherosclerosis. Evidence for pairwise colocalization between dementia and stroke, dementia (or AD) and atherosclerosis, and dementia (or AD) and diabetes was found in 2, 6 and 2 genetic regions respectively. Colocalization signals between diabetes and the other 3 non-dementia/AD traits were detected in 5 regions. The colocalization evidence shown in our study suggested shared aetiology between dementia and related diseases such as stroke, atherosclerosis, and diabetes.

High-density lipoprotein-cholesterol and incident type 2 diabetes mellitus among African Americans: The Jackson Heart Study

AIMS

Accruing evidence suggests an association between high-density lipoprotein cholesterol (HDL-C) and incident diabetes. However, there is a paucity of data on the link between HDL-C and diabetes, especially among African Americans (AAs). We aimed to assess the association of HDL-C and its fractions with incident type 2 diabetes among AAs.

METHODS

We included Jackson Heart Study participants who attended visit 1 (2001-2004), were free from diabetes and were not treated with lipid-modifying medications. Incident diabetes was assessed at two subsequent-yearly visits (2 and 3). We cross-sectionally assessed the association of HDL-C and insulin resistance (IR) using multivariable linear models. We prospectively assessed the association of HDL-C and its fractions with incident diabetes using multivariable Cox regression models.

RESULTS

Among 2829 participants (mean age: 51.9 ± 12.4 years, 63.9% female), 487 participants (17%) developed new-onset diabetes, over a median follow-up of 8 years. In adjusted models, a higher HDL-C concentration was associated with a lower odds of IR (odds ratio [OR] per standard deviation [SD] increment: OR 0.56 [95% confidence interval, CI 0.50-0.63], p < 0.001). In adjusted models, a higher HDL-C concentration was associated with a lower risk of diabetes (HR per SD increment: 0.78 [95% CI 0.71, 0.87], p < 0.001; HR for highest vs. the lowest tertile of HDL-C was 0.56 [95% CI: 0.44, 0.71], p < 0.001).

CONCLUSION

In a sample of African-American adults not on any lipid-modifying therapy, high HDL-C concentrations were inversely associated with the risk of new-onset diabetes. These findings suggest a strong link between HDL-C metabolism and glucose regulation.

Gamma-glutamyl transferase to high-density lipoprotein cholesterol ratio: A valuable predictor of type 2 diabetes mellitus incidence

BACKGROUND

Gamma-glutamyl transferase (GGT) and high-density lipoprotein cholesterol (HDL-C) have been proven to be valuable predictors of type 2 diabetes mellitus (T2DM). The aim of this study was to investigate the association between GGT/HDL-C ratio and incident T2DM.

METHODS

The study retrospectively analyzed 15453 participants from 2004 to 2015. Cox proportional hazards regression models and Kaplan-Meier curves were used to elucidate the effect of GGT/HDL-C ratio on T2DM. Restricted cubic spline (RCS) analysis was performed to explore any non-linear correlation between GGT/HDL-C ratio and the risk of T2DM. The predictive performance of GGT, HDL-C and GGT/HDL-C ratio for T2DM was evaluated utilizing receiver-operating-characteristic (ROC) curves.

RESULTS

During a median follow-up of 5.39 years, 373 cases of incident T2DM were observed. Kaplan-Meier curves showed that the cumulative probabilities of T2DM increased in the participants with higher GGT/HDL-C ratio significantly (P < 0.001). Cox models further clarified that high GGT/HDL-C ratio was an independent risk factor for T2DM (HR = 1.01, 95% CI = 1.00-1.01, P = 0.011). Linear positive correlation between GGT/HDL-C ratio and the risk of T2DM was demonstrated through RCS analysis. In the ROC analysis, GGT/HDL-C ratio (AUC = 0.75, 95% CI = 0.73-0.77) showed competitive role in the prediction of T2DM compared with single GGT and HDL-C.

CONCLUSIONS

The GGT/HDL-C ratio could serve as a valuable predictor of T2DM, and the risk of T2DM increases in the condition of higher GGT/HDL-C ratio.

Sonographic Optic Nerve Diameter and Clinical Biomarkers in Patients With Poorly Controlled Diabetes: A Comparative Analysis With Nondiabetic Subjects

Objective:

The study assessed optic nerve diameter (OND) and clinical biomarkers in patients with poorly controlled diabetes compared with healthy nondiabetic volunteers.

Materials and Methods:

There were 1320 adult participants recruited to the study. The cohort was divided into 600 Type 2 diabetic (DM II) patients and 720 apparently healthy, nondiabetic volunteers. The OND was measured using a high-resolution dedicated ultrasound device (Sonoace 5500; Medicol, Medison, Miami, FL, USA) with a 10-MHz linear array transducer. Subjects were examined in a supine position with their eyes closed. Three measurements of the OND were taken and the average recorded. Hemoglobin A1c concentration and lipid profiles were determined using Bio-Rad Diamat analyzer (Bio-Rad, Hercules, CA). Body mass index and age were matched for both cohorts for comparativeness.

Results:

The mean OND of the DM II patients was 3.10 ± 0.14 mm (range of 2.6–4.0 mm), which was significantly ( P < .05) lower than the control volunteers (4.22 ± 0.15 mm). The OND demonstrated a negative significant correlation with HA1c, duration of diabetes and low-density lipoprotein cholesterol level ( P < .05). Lipid profiles, blood urea, serum creatinine, and hemoglobin A1c showed statistical difference between diabetics and control subjects.

Conclusion:

Poorly controlled DM II patients may have significantly narrower OND than nondiabetic patients. This imaging biomarker has the potential to transform visual care for DM II patients.

The Variant rs1784042 of the SIDT2 Gene is Associated with Metabolic Syndrome through Low HDL-c Levels in a Mexican Population

The Mexican population has one of the highest prevalences of metabolic syndrome (MetS) worldwide. The aim of this study was to investigate the association of single-nucleotide polymorphisms (SNPs) with MetS and its components. First, we performed a pilot Genome-wide association study (GWAS) scan on a sub-sample derived from the Health Workers Cohort Study (HWCS) (n = 411). Based on GWAS results, we selected the rs1784042 and rs17120425 SNPs in the SIDT1 transmembrane family member 2 (SIDT2) gene for replication in the entire cohort (n = 1963), using predesigned TaqMan assays. We observed a prevalence of MetS in the HWCS of 52.6%. The minor allele frequency for the variant rs17120425 was 10% and 29% for the rs1784042. The SNP rs1784042 showed an overall association with MetS (OR = 0.82, p = 0.01) and with low levels of high-density lipoprotein (HDL-c) (odds ratio (OR) = 0.77, p = 0.001). The SNP rs17120425 had a significant association with type 2 diabetes (T2D) risk in the overall population (OR = 1.39, p = 0.033). Our results suggest an association of the rs1784042 and rs17120425 variants with MetS, through different mechanisms in the Mexican population. Further studies in larger samples and other populations are required to validate these findings and the relevance of these SNPs in MetS.

Patterns of changes in serum lipid profiles in prediabetic subjects: results from a 16-year prospective cohort study among first-degree relatives of type 2 diabetic patients

BACKGROUND

Lipid abnormality pervasively is associated with the risk of type 2 diabetes mellitus. To the best of our knowledge, there is no study that has examined the longitudinal changes in a wide range of serum lipid profiles in prediabetic subjects in association with the risk of developing type 2 diabetes mellitus in the future. This study aimed to identify the patterns of changes in lipid profiles over time in prediabetic patients and to classify these subjects in order to highlight which patients are at high risk for future diabetes.

METHODS

This prospective 16-year (2003-2019) cohort study was conducted among 1228 prediabetic subjects. The study subjects were followed, and the changes in their lipid profiles, including triglycerides, cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol, were evaluated. The latent Markov model was used for data analysis.

RESULTS

The mean (standard deviation) age of subjects was 44.0 (6.8) years, and 73.6% of them were female. The latent Markov model identified two latent states of subjects in terms of changes in lipid profiles: a low tendency to progress diabetes / high tendency to progress diabetes (74, 26%). The latent Markov model showed that the transition probability from a "low tendency to progress diabetic" state to a "high tendency to progress diabetic" state was lower than the transition probability from "high tendency to progress diabetic" state to "low tendency to progress diabetic" state.

CONCLUSIONS

The present study showed that more than half of the first-degree relatives of T2DM had approximately normal lipid profiles and that these patients are more inclined to transition from a higher- to a lower-tendency diabetic state. These findings confirm the value of regular screening of first-degree relatives of T2DM. Moreover, preventive intervention strategies are recommended to reduce their risk of developing T2DM.

R230C but not - 565C/T variant of the ABCA1 gene is associated with type 2 diabetes in Mexicans through an effect on lowering HDL-cholesterol levels

PURPOSE

Type 2 diabetes (T2D) and low serum concentration of high-density lipoprotein cholesterol (HDL-c) are common coexisting metabolic disorders. ABCA1 variants have been shown to be associated to these conditions. We sought to test the combined effect of two ABCA1 gene common variants, rs2422493 (- 565C > T) and rs9282541 (R230C) on HDL-c levels and T2D risk.

METHODS

Path analysis was conducted in 3,303 Mexican-mestizos to assess the specific contributions of rs2422493 and rs9282541 ABCA1 variants, insulin resistance, waist-to-height ratio (WHtR), and age on HDL-c levels and T2D risk. Participants were classified into four groups according to their ABCA1 variants carrier status: (i) the reference group carried wild type alleles for both ABCA1 variants (-/-), (ii)  +/-  were carriers of rs2422493 but non-carriers of rs9282541, (iii) -/+ for carriers of rs9282541 but not carriers of rs2422493 and (iv) carriers of minor alleles for both SNPs (+/+). Principal components from two previous genome-wide association studies were used to control for ethnicity.

RESULTS

We identified significant indirect effects on T2D risk mediated by HDL-c in groups -/+ and +/+ (β = 0.04; p = 0.03 and β = 0.06; p < 0.01, respectively) in comparison to the -/- reference group. Low concentrations of HDL-c were directly and significantly associated with increased T2D risk (β = -0.70; p < 0.01). WHtR, male gender, age, and insulin resistance were also associated with T2D risk (p < 0.05). There was no significant direct effect for any of the ABCA1 groups on T2D risk: p = 0.99, p = 0.58, and p = 0.91 for groups +/-, -/+, and +/+ respectively.

CONCLUSIONS

The ABCA1 rs9282541 (R230C) allele is associated with T2D in Mexicans through its effect on lowering HDL-c levels. This is the first report demonstrating that HDL-c levels act as an intermediate factor between an ABCA1 variant and T2D.

A 50-year history of the health impacts of Westernization on the lifestyle of Japanese Americans: A focus on the Hawaii-Los Angeles-Hiroshima Study

A medical survey of Japanese Americans have been carried out since 1970; in particular, this survey was administered to the Japanese emigrants from Hiroshima (Japan) to Hawaii or Los Angeles (USA) and their offspring. Labeled the Hawaii–Los Angeles–Hiroshima Study, it constituted a long‐term epidemiological study of Japanese Americans who are genetically identical to the native Japanese people, but have experienced rapid and intense Westernization in terms of their lifestyles. The authors have compared the medical survey data procured from two Japanese populations, evincing very disparate lifestyles; that is, the native Japanese inhabitants of Hiroshima (Japan) and Japanese Americans living in Hawaii or Los Angeles (USA). The focus was particularly on differences in the intake of nutrients, the frequency of obesity, the prevalence of metabolic syndrome and diabetes mellitus, and the progression of atherosclerosis. The authors believe that the health effects of the lifestyles of Japanese Americans can predict the imminent health prospects of native Japanese people who adopt Westernized lifestyles in Japan. This review thus summarized the major results accumulated from the Hawaii–Los Angeles–Hiroshima Study over the past 50 years.

The cut-off value of impaired fasting glucose should be lower: Based on the associations of fasting blood glucose with blood lipids

OBJECTIVE

The previous study served impaired fasting glucose (IFG), a pre-diabetic state which was much greater than that of diabetic patients, have reached no consensus on its cut-off value. In this study, we aimed to explore the cut-off value of IFG via the associations of blood lipids with fasting plasma glucose (FPG).

DESIGN

A cross-sectional study in Jilin province, China, 2012.

SAMPLE

13,093 participants aged 18-79 years in Jilin province were involved in the study. The Lamba-Mu-Sigma (LMS) method and generalized additive model (GAM) were used to explore the associations of different levels of FPG and blood lipids.

RESULTS

The distributions of FPG, triglyceride (TG) and high-density lipoprotein cholesterol (HDL-c) were significantly different by gender (p<0.01). In general, both LMS and GAM results showed that the TG and HDL-c curves had a steeper tendency when the FPG was greater than 6.0mmol/L.

CONCLUSION

FPG was positively associated with TG while negatively associated with HDL-c, and the associations were stronger in females. The cut-off value of IFG was suggested to be 6.0mmol/L.

High Incidence of Diabetes in People with Extremely High High-Density Lipoprotein Cholesterol: Results of the Kanagawa Investigation of Total Checkup Data from the National Database-1 (KITCHEN-1)

BACKGROUND

It is unknown whether extremely high high-density lipoprotein cholesterol (HDL-C) has a protective effect against diabetes, which plays a key role in cardiovascular disease.

METHODS

In a community-based cohort study of 387,642 subjects (40⁻68 years old) without diabetes, the incidence of diabetes 6 years later was determined according to baseline HDL-C (≤39, 40⁻49, 50⁻59, 60⁻69, 70⁻79, 80⁻89, 90⁻99, 100⁻109, or ≥110 mg/dL).

RESULTS

At baseline, HDL-C ≥100 mg/dL was present in 12,908 subjects (3.3%), who had a better lipid profile and a high prevalence of heavy alcohol consumption and habitual exercise. The incidences of diabetes according to baseline HDL-C were 14.7, 11.2, 7.7, 5.3, 3.8, 2.8, 2.7, 2.5, and 3.5 per 1000 person-years, respectively. The adjusted relative risks (ARRs) for diabetes showed concave relationships with HDL-C, with minima at 80⁻89 mg/dL. The ARR (95% CI) of the lowest HDL-C category was 1.56 (1.40⁻1.74) and of the highest HDL-C category was 1.46 (1.18⁻1.81) (both p < 0.001), regardless of alcohol consumption. The latter ARR was higher in men (n = 219,047) (2.45 (1.70⁻3.53), p < 0.0001) after adjustment for baseline glycemic index.

CONCLUSION

Both extremely high and low HDL-C represent risks for diabetes, which deserves further study.

Short-Term Consumption of Cuban Policosanol Lowers Aortic and Peripheral Blood Pressure and Ameliorates Serum Lipid Parameters in Healthy Korean Participants: Randomized, Double-Blinded, and Placebo-Controlled Study

The current study was designed to investigate the short-term effects of policosanol consumption on blood pressure (BP) and the lipid parameters in healthy Korean participants with prehypertension. A total of 84 healthy participants were randomly allocated to three groups receiving placebo, 10 mg of policosanol, or 20 mg of policosanol for 12 weeks. Based on an average of three measurements of peripheral BP, the policosanol 20 mg group exhibited the most significant reduction, that is, up to 7.7% reduction of average systolic BP (SBP) from 136.3 ± 6.1 mmHg (week 0) to 125.9 ± 8.6 mmHg (week 12, p < 0.001). Between group comparisons using repeated measures ANOVA showed that the policosanol 20 mg group had a significant reduction of SBP at 12 weeks (p = 0.020) and a reduction of diastolic BP (DBP) at 8 weeks (p = 0.041) and 12 weeks (p = 0.035). The policosanol 10 mg and 20 mg groups showed significant reductions in aortic SBP of 7.4% and 8.3%, respectively. The policosanol groups showed significant reductions of total cholesterol (TC) of 9.6% and 8.6% and low-density lipoproteins (LDL-C) of 21% and 18% for 10 mg and 20 mg of policosanol, respectively. Between group comparisons using repeated measures ANOVA showed that the policosanol (10 mg and 20 mg) groups at 12 weeks had a significant reduction of TC (p = 0.0004 and p = 0.001) and LDL-C (p = 0.00005 and p = 0.0001) and elevation of %HDL-C (p = 0.048 and p = 0.014). In conclusion, 12-week consumption of policosanol resulted in significant reductions of peripheral SBP and DBP, aortic SBP and DBP, mean arterial pressure (MAP), and serum TC and LDL-C with elevation of % HDL-C.

Long-Term Consumption of Cuban Policosanol Lowers Central and Brachial Blood Pressure and Improves Lipid Profile With Enhancement of Lipoprotein Properties in Healthy Korean Participants

Metabolic syndrome is closely associated with higher risk of hypertension, cardiovascular disease (CVD), diabetes and stroke. The aim of the present study was to investigate the long-term effects of policosanol supplementation on blood pressure (BP) and the lipid profile in healthy Korean participants with pre-hypertension (systolic 120–139 mmHg, diastolic 85–89 mmHg). This randomized, double-blinded, and placebo-controlled trial included 84 healthy participants who were randomly assigned to three groups receiving 10 mg of policosanol, 20 mg of policosanol, or placebo for 24 weeks. The BP, lipid profile, and anthropometric factors were measured pre- and post-intervention and then compared. Based on an average of three measurements of brachial BP, the policosanol 20 mg group showed the most significant reduction in average systolic BP (SBP) from 138 ± 12 mmHg at week 0 to 126 ± 13 mmHg at week 24 (p < 0.0001). The policosanol 20 mg group also showed significant reductions in aortic SBP and DBP up to 9% (p = 0.00057) and 8% (p = 0.004), respectively compared with week 0. Additionally, blood renin and aldosterone levels were significantly reduced in the policosanol 20 mg group up to 63% (p < 0.01) and 42% (p < 0.05), respectively, at week 24. For the blood lipid profile, the policosanol 10 mg and 20 mg groups showed significant reductions in total cholesterol (TC) of around 8% (p = 0.029) and 13% (p = 0.0004), respectively, at week 24 compared with week 0. Serum HDL-C level significantly increased up to 16% and 12% in the policosanol 10 mg (p = 0.002) and 20 mg (p = 0.035) group, respectively. The study results suggest that long-term policosanol consumption simultaneously reduces peripheral BP as well as aortic BP accompanied by elevation of HDL-C and % HDL-C in TC in a dose-dependent manner.

The role and function of HDL in patients with diabetes mellitus and the related cardiovascular risk

BACKGROUND

Diabetes mellitus (DM) is a major public health problem which prevalence is constantly raising, particularly in low- and middle-income countries. Both diabetes mellitus types (DMT1 and DMT2) are associated with high risk of developing chronic complications, such as retinopathy, nephropathy, neuropathy, endothelial dysfunction, and atherosclerosis.

METHODS

This is a review of available articles concerning HDL subfractions profile in diabetes mellitus and the related cardiovascular risk. In this review, HDL dysfunction in diabetes, the impact of HDL alterations on the risk diabetes development as well as the association between disturbed HDL particle in DM and cardiovascular risk is discussed.

RESULTS

Changes in the amount of circulation lipids, including triglycerides and LDL cholesterol as well as the HDL are frequent also in the course of DMT1 and DMT2. In normal state HDL exerts various antiatherogenic properties, including reverse cholesterol transport, antioxidative and anti-inflammatory capacities. However, it has been suggested that in pathological state HDL becomes "dysfunctional" which means that relative composition of lipids and proteins in HDL, as well as enzymatic activities associated to HDL, such as paraoxonase 1 (PON1) and lipoprotein-associated phospholipase 11 (Lp-PLA2) are altered. HDL properties are compromised in patients with diabetes mellitus (DM), due to oxidative modification and glycation of the HDL protein as well as the transformation of the HDL proteome into a proinflammatory protein. Numerous studies confirm that the ability of HDL to suppress inflammatory signals is significantly reduced in this group of patients. However, the exact underlying mechanisms remains to be unravelled in vivo.

CONCLUSIONS

The understanding of pathological mechanisms underlying HDL dysfunction may enable the development of therapies targeted at specific subpopulations and focusing at the diminishing of cardiovascular risk.

Low Levels of High-Density Lipoprotein Cholesterol Do Not Predict the Incidence of Type 2 Diabetes in an Iranian High-Risk Population: The Isfahan Diabetes Prevention Study

OBJECTIVES

To evaluate the ability of low-level fasting high-density lipoprotein cholesterol (HDLC) to predict the incidence of type 2 diabetes (T2D) in an Iranian high-risk population.

METHODS

Seven-year follow-up data (n = 1,775) in non-diabetic first-degree relatives (FDR) of consecutive patients with T2D aged 30-70 years were analyzed. The primary outcome was the diagnosis of T2D based on repeated oral glucose tolerance test (OGTT). We used Cox proportional hazard models to estimate the hazard ratio (HR) for the incidence of T2D across quartiles of HDLC, and plotted a receiver operating characteristic (ROC) curve to assess discrimination.

RESULTS

The highest quartile compared with the lowest quartile of HDLC was associated with T2D in age- and gender-adjusted models (HR: 0.83, 95% CI: 0.73-0.95). Further adjustment for fasting plasma glucose and cholesterol attenuated the association for T2D incidence (HR: 0.93, 95% CI: 0.80-1.08). The area under the ROC curve for HDLC was 54.1% (95% CI: 50.2-58.0).

CONCLUSIONS

HDLC level was a weak predictor of T2D in an Iranian high-risk population, independent of age and gender.

Assessment of established HDL-C loci for association with HDL-C levels and type 2 diabetes in Pima Indians

AIMS/HYPOTHESIS

Epidemiological studies in Pima Indians identified elevated levels of HDL-cholesterol (HDL-C) as a protective factor against type 2 diabetes risk in women. We assessed whether HDL-C-associated single-nucleotide polymorphisms (SNPs) also associate with type 2 diabetes in female Pima Indians.

METHODS

Twenty-one SNPs in established HDL-C loci were initially analysed in 2,675 full-heritage Pima Indians. SNPs shown to associate with HDL-C (12 SNPs) were assessed for association with type 2 diabetes in 7,710 Pima Indians (55.6% female sex). The CETP locus provided the strongest evidence for association with HDL-C and was further interrogated by analysing tag SNPs.

RESULTS

Twelve of the 21 SNPs analysed had a significant association with HDL-C in Pima Indians; five SNPs representing four loci (CETP, DOCK6, PPP1R3B and ABCA1) reached genome-wide significance. Three SNPs, at CETP, KLF14 and HNF4A, associated with type 2 diabetes only in female participants with the HDL-C-lowering allele increasing diabetes risk (p values: 3.2 × 10(-4) to 7.7 × 10(-5)); the association remained significant even after adjustment for HDL-C. Additional analysis across CETP identified rs6499863 as having the strongest association with type 2 diabetes in female participants (p = 5.0 × 10(-6)) and this association remained independent of the HDL-C association.

CONCLUSIONS/INTERPRETATION

SNPs at the CETP, HNF4A and KLF14 locus are associated with HDL-C levels and type 2 diabetes (in female participants). However, since HNF4A and KLF14 are established loci for type 2 diabetes, it is unlikely that HDL-C solely mediates these associations.

Low high-density lipoprotein cholesterol level is a significant risk factor for development of type 2 diabetes: Data from the Hawaii-Los Angeles-Hiroshima study

Aims/Introduction

A low level of high‐density lipoprotein cholesterol (HDLC) is a common feature of metabolic syndrome. We have reported that Japanese–Americans who share a virtually identical genetic makeup with native Japanese, but who have lived Westernized lifestyles for decades, have lower HDLC levels and a high prevalence of type 2 diabetes compared with native Japanese. However, the impact of low HDLC level on type 2 diabetes is unclear. The aims of the present study were to evaluate whether serum HDLC level was associated with development of type 2 diabetes and if the effect might be modified by lifestyle.

Materials and Methods

We examined 1,133 non‐diabetic Japanese–Americans and 1,072 non‐diabetic Japanese, who underwent the 75‐g oral glucose tolerance test (OGTT) and were followed for an average of 8.8 and 7.0 years, respectively. We analyzed whether serum HDLC level is a risk factor for development of type 2 diabetes based on the Cox proportional hazards model.

Results

After adjustment for age and sex, hazard ratios for development of type 2 diabetes per unit of serum HDLC level (mmol/L) were 0.292 (95% confidence interval [CI] 0.186–0.458, P < 0.0001) among Japanese–Americans and 0.551 (95% CI 0.375–0.88, P = 0.0023) among native Japanese. Comparable hazard ratios after further adjustment for category of OGTT and body mass index were 0.981 (95% CI 0.970–0.993, P = 0.0018) and 0.991 (95% CI 0.980–1.002, P = 0.112), respectively.

Conclusions

HDLC level was associated with development of type 2 diabetes in both Japanese–Americans and native Japanese. However, these results suggest that the impact of high‐density lipoprotein on glucose metabolism might be affected by lifestyle.