Association Between the Hypertriglyceridemic Waist Phenotype, Prediabetes, and Diabetes Mellitus Among Adults in Puerto Rico

Prevalence and incidence of prediabetes in Latin America. A systematic review and meta-analysis

Introduction

Prediabetes represents a significant public health challenge in Latin America. Its prevalence varies considerably depending on the diagnostic criteria used, which hinders a precise understanding of its magnitude in the region.

Objective

To estimate the prevalence and incidence of prediabetes in Latin America through a systematic review (SR).

Methods

A SR and meta-analysis was conducted searching through October 25, 2024 in SCOPUS, EMBASE, Web of Science, and PubMed. Studies were included if they: (1) used probabilistic sampling methods, (2) included adult participants (≥ 18 years), (3) assessed prediabetes using WHO criteria, fasting glucose, postprandial glucose, or HbA1c, and (4) were published in English, Spanish, or Portuguese. Studies using non-probabilistic sampling, focusing on specific medical conditions, or lacking sufficient data to calculate prevalence or incidence were excluded. Random-effect models were used to estimate pooled prevalence, with heterogeneity assessed using I² statistics and publication bias through funnel plots.

Results

Twenty-five studies from 9 countries published between 1992 and 2023 were analyzed. The pooled prevalence of prediabetes was 24% (95% CI: 18-30%). According to specific criteria, the prevalences were: WHO 11% (95% CI: 5-18%), FG 18% (95% CI: 10-27%), PPG 20% (95% CI: 3-46%), and HbA1c 32% (95% CI: 21-52%). High heterogeneity was observed among studies (I² = 99-100%, p < 0.001). Only one study analyzed the incidence, which was 12.8%.

Conclusions

Prediabetes prevalence in Latin America is high, with significant variations by diagnostic criteria. The limited number of incidence studies and high heterogeneity highlight the need for standardized approaches in future research. Implementation of preventive strategies and strengthening of epidemiological surveillance systems are crucial for addressing this public health challenge.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-024-01549-6.

[Hypertension-abdominal obesity phenotype as an indicator of dysglycaemia and insulin resistance]

Objective

To determine the usefulness of the hypertension-abdominal obesity phenotype as an indicator of dysglycaemia and insulin resistance.

Materials and Methods

Cross-sectional descriptive study of 964 adults (449 women and 515 men) who attended the Institute of Endocrinology with risk of diabetes mellitus. Demographic (age, sex, skin colour), clinical (blood pressure and acanthosis nigricans), anthropometric (weight, height, waist circumference and body mass index) and laboratory (basal and oral glucose tolerance test-stimulated blood glucose and insulinaemia) variables were analysed. The insulin resistance index was calculated. The abdominal hypertension-obesity phenotype was defined as the presence of systolic pressure ≥130 mm Hg and/or diastolic pressure ≥80 mm Hg or treated hypertension, waist circumference ≥80 cm in women and ≥90 cm in men. Sensitivity, specificity and predictive values of the abdominal obesity hypertension phenotype were calculated to identify dysglycaemia and insulin resistance.

Results

Individuals with the hypertension-abdominal obesity phenotype showed a higher proportion of impaired glucose metabolism and insulin resistance than those without the phenotype (p<0.0001). The hypertension-abdominal obesity phenotype better identifies persons with the presence of double prediabetes, diabetes mellitus and insulin resistance, as they show high sensitivities (85.9%, 77.5%, and 68.9%, respectively), and high negatives predictive values (97.9%, 95.8%, and 74.0%, respectively).

Conclusions

The hypertension-abdominal obesity phenotype is a simple, useful option for identifying persons with dysglycaemia, and insulin resistance.

Association between hypertriglyceridemic-waist phenotype and non-alcoholic fatty liver disease: a general population-based study

BACKGROUND

Hypertriglyceridemic-waist (HTGW) phenotype has been proposed as a practical tool for screening the risk of cardiovascular diseases and glycemic metabolic disease. This study sought to investigate the relationship between HTGW phenotype and non-alcoholic fatty liver disease (NAFLD).

METHODS

A total of 14,251 subjects who took part in health screening were enrolled in the study and NAFLD was diagnosed by abdominal ultrasound. According to triglyceride (TG) and waist circumference, the study population was divided into four phenotypes, in which HTGW phenotype was defined as TG ≥ 1.7 mmol/L and male waist circumference ≥ 90 cm or female waist circumference ≥ 80 cm. Multivariate logistic regression analysis was used to evaluate the relationship between HTGW phenotype and NAFLD.

RESULTS

In the current study, 2.43% of the subjects had HTGW phenotype, while the prevalence of NAFLD in subjects with HTGW phenotype was 77.81%. After full adjustment for covariates, compared with people with normal waist circumference and TG levels, the risk of NAFLD in people with normal TG levels but enlarged waist circumference increased by 39% [OR:1.39, 95%CI: 1.15, 1.68], in people with normal waist circumference but elevated TG levels increased by 96% [OR:1.96, 95%CI: 1.65, 2.33], and in subjects with HTGW phenotype increased by 160% [OR:2.60, 95%CI: 1.88, 3.58]. Additionally, further analysis suggested that there were significant interactions between age, height, BMI and NAFLD risk associated with TGW phenotypes. Receiver operating characteristic curves analysis suggested that the combination of TG and waist circumference further improved the diagnostic value for NAFLD.

CONCLUSIONS

HTGW phenotype is associated with NAFLD risk in the general population, which may be a novel and accessible indicator for NAFLD screening.

Association between Hypertriglyceridemic-Waist Phenotype and Risk of Type 2 Diabetes Mellitus in Middle-Aged and Older Chinese Population: A Longitudinal Cohort Study

Current evidence remains inconsistent with regard to the association between different triglyceridemic-waist phenotypes and the risks for type 2 diabetes mellitus (T2DM). We aimed to investigate this association among a retrospective cohort analysis of 6918 participants aged ≥ 45 years in the China Health and Retirement Longitudinal Study (CHARLS). Participants were categorized into four triglyceridemic-waist phenotypes consisting of NWNT (normal waist circumference and normal triglycerides), NWHT (normal waist circumference and high triglycerides), EWNT (enlarged waist circumference and normal triglycerides), and EWHT (enlarged waist circumference and high triglycerides) based on participants’ baseline information. Multivariate log-binomial regression was used to assess the T2DM risk in different phenotypes. Subgroup analysis was conducted to test the robustness of the findings. After 4-years of follow-up, participants with EWHT (Relative Risk [RR]: 1.909, 95% Confidence Interval [CI]: 1.499 to 2.447) or EWNT (RR: 1.580, 95%CI: 1.265 to 1.972) phenotypes had significantly higher likelihood of incident T2DM compared to the NWNT phenotype, whereas the association was not significant for the NWHT phenotype (RR: 1.063, 95%CI: 0.793 to 1.425). The subgroup analyses generally revealed similar associations across all subgroups. Among middle-aged and older adults, we suggested a combined use of waist circumference and triglycerides measures in identifying participants who are at high risk of developing T2DM.

Hypertriglyceridemic waist phenotype and risk of chronic kidney disease in community-dwelling adults aged 60 years and older in Tianjin, China: a 7-year cohort study

Background

The hypertriglyceridemic waist (HTGW) phenotype has been proposed to be related to the occurrence and progression of chronic kidney disease (CKD). The ageing trend of the Chinese population continues to intensify, and elderly individuals are at high risk of CKD. The purpose of this study was to investigate the cross-sectional and longitudinal associations between the HTGW phenotype and the risk of CKD by following community-dwelling adults aged 60 years and older in Tianjin, China, for 7 years.

Methods

This study was an observational cohort study conducted between 2013 and 2019. Of 2050 participants aged 60 years and older who underwent an annual health examination in 2013, 1605 individuals with complete data were enrolled in the cross-sectional analysis. Among them, 1271 individuals were observed until 2019. Detailed follow-up records were available for 816 participants, of whom 600 participants without CKD at baseline were eligible for inclusion in the retrospective analysis. The HTGW phenotype was defined as a waist circumference of 90 cm or more and triglyceride concentrations of 2.0 mmol/L or more in males or a waist circumference of 85 cm or more and triglyceride concentrations of 1.5 mmol/L or more in females. CKD was defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73m² and/or proteinuria (urinary albumin-to-creatinine ratio (ACR) ≥ 30 mg/g). Multivariable logistic regression analyses were performed to evaluate the relationship between the HTGW phenotype and CKD.

Results

In 2013, the prevalence of CKD among older adults was 31.03%, and the prevalence of CKD in the HTGW phenotype group was 37.81%. Over a 7-year observation period, 195 individuals developed CKD, with an incidence rate of 32.50%. Statistically significant associations were observed between the HTGW phenotype and CKD in older adults in both cross-sectional surveys and retrospective analyses, with odds ratios and 95% confidence intervals of 1.38 (95% CI: 1.03–1.86, P = 0.033) and 2.27 (95% CI: 1.30–3.97, P = 0.004), respectively, after adjustment for confounders.

Conclusions

In this community-based cohort study, the HTGW phenotype was confirmed to be independently associated with an increased risk of prevalent and incident CKD in older adults aged 60 years and above in Tianjin, China.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02339-5.

The relationship between hypertriglyceridemic waist circumference phenotype and gestational diabetes mellitus

AIMS

To investigate the correlation between hypertriglyceridemic waist circumference (HTWC) phenotype and gestational diabetes mellitus (GDM).

METHODS

A total of 1083 patients with gestational age ≤8 weeks were divided into four groups: normal triglyceride and waist circumference group (group A, n = 575), simple abdominal obesity group (group B, n = 317), simple high triglyceride group (group C, n = 125), and HTWC group (group D, n = 66). General information and serum biochemical indicators were measured and recorded. Analysis of variance (ANOVA) and logistic regression analysis were used to evaluate the relationship between HTWC with GDM.

RESULTS

The prevalence of GDM in the HTWC group was significantly greater than in the other three groups. After adjustment by multivariate logistic regression analysis, the proportion of GDM in the HTWC group was 1.753 times higher than in group A.

CONCLUSION

These findings suggest that there is a significant correlation between HTWC phenotype and GDM, indicating that the HTWC phenotype could be applied as a simple marker for identifying GDM risk factors.

Association of "hypertriglyceridemic waist" with increased 5-year risk of subclinical atherosclerosis in a multi-ethnic population: a prospective cohort study

BACKGROUND

Hypertriglyceridemic waist (HTGW), which incorporates measures of waist circumference and levels of triglyceride in blood, could act as an early-stage predictor to identify the individuals at high-risk for subclinical atherosclerosis. Previous studies have explored the cross-sectional association between HTGW and atherosclerosis; however, understanding how this association might change over time is necessary. This study will assess the association between HTGW with 5-year subclinical carotid atherosclerosis.

METHODS

517 participants of Aboriginal, Chinese, European, and South Asian ethnicities were examined for baseline HTGW and 5-year indices of subclinical atherosclerosis (intima media thickness (mm), total area (mm2), and plaque presence). Family history of cardiovascular disease, sociodemographic measures (age, sex, ethnicity, income level, maximum education), and traditional risk factors (systolic blood pressure, smoking status, total cholesterol, high-density lipoprotein cholesterol, body mass index) were incorporated into the models of association. These models used multiple linear regression and logistic regression.

RESULTS

Baseline HTGW phenotype is a statistically significant and clinically meaningful predictor of 5-year intima media thickness (β = 0.08 [0.04, 0.11], p < 0.001), total area (β = 0.20 [0.07, 0.33], p = 0.002), and plaque presence (OR = 2.17 [1.13, 4.19], p = 0.02) compared to the non-HTGW group independent of sociodemographic factors and family history. However, this association is no longer significant after adjusting for the traditional risk factors of atherosclerosis (p = 0.27, p = 0.45, p = 0.66, respectively). Moreover, change in status of HTGW phenotype does not correlate with change in indices of atherosclerosis over 5 years.

CONCLUSIONS

Our results suggest that when the traditional risk factors of atherosclerosis are known, HTGW may not offer additional value as a predictor of subclinical atherosclerosis progression over 5 years.

Hypertriglyceridemic Waist Phenotype and Lipid Accumulation Product: Two Comprehensive Obese Indicators of Waist Circumference and Triglyceride to Predict Type 2 Diabetes Mellitus in Chinese Population

PURPOSE

To determine whether hypertriglyceridemic waist (HTGW) and high lipid accumulation product (LAP) preceded the incidence of type 2 diabetes mellitus (T2DM), and to investigate the interactions of HTGW and LAP with other components of metabolic syndrome on the risk of T2DM.

METHODS

A total of 15,717 eligible participants without baseline T2DM and aged 35 and over were included from a Chinese rural cohort. Cox proportional hazards regression models were used to estimate the association of HTGW and LAP with the incidence of T2DM, and the restricted cubic spline model was used to evaluate the dose-response association.

RESULTS

Overall, 867 new T2DM cases were diagnosed after 7.77 years of follow-up. Participants with HTGW had a higher hazard ratio for T2DM (hazard ratio (HR): 6.249, 95% confidence interval (CI): 5.199-7.511) after adjustment for potential confounders. The risk of incident T2DM was increased with quartiles 3 and 4 versus quartile 1 of LAP, and the adjusted HRs (95% CIs) were 2.903 (2.226-3.784) and 6.298 (4.911-8.077), respectively. There were additive interactions of HTGW (synergy index (SI): 1.678, 95% CI: 1.358-2.072) and high LAP (SI: 1.701, 95% CI: 1.406-2.059) with increased fasting plasma glucose (FPG) on the risk of T2DM. Additionally, a nonlinear (P nonlinear < 0.001) dose-response association was found between LAP and T2DM.

CONCLUSION

The subjects with HTGW and high LAP were at high risk of developing T2DM, and the association between LAP and the risk of T2DM may be nonlinear. Our study further demonstrates additive interactions of HTGW and high LAP with increased FPG on the risk of T2DM.

Hypertriglyceridemic waist phenotype and abnormal glucose metabolism: a system review and meta-analysis

OBJECTIVE

This study was to perform a meta-analysis to assess the relationship between hypertriglyceridemic-waist (HTW) phenotype and abnormal glucose metabolism.

METHODS

The data sources were PubMed and EMBASE up to June 2018. Studies providing the relationship between HTW phenotype and abnormal glucose metabolism were included.

RESULTS

In total, 48 eligible studies that evaluated 2,42,879 subjects were included in the meta-analysis. In the general population, the pooled odds ratios (ORs) for elevated blood glucose and diabetes related to HTW phenotype was 2.32 (95% confidence interval (CI): 1.98-2.71) and 2.69 (95% CI: 2.40-3.01), respectively. In cohort studies, the pooled OR for diabetes related to HTW phenotype was 2.89 (95% CI: 1.97-4.25) in subjects without diabetes. The levels of homeostasis model assessment of insulin resistance (HOMA-IR) in the HTW population were increased with values of mean differences (MD) 1.12 (95% CI: 0.81-1.43. P < 0.00001, I² = 99%) in the general population and 0.89 (95% CI: 0.75-1.04, P < 0.00001, I² = 67%) in subjects without diabetes.

CONCLUSION

HTW phenotype was closely associated with increased risk of abnormal glucose metabolism. There was also a significant correlation between HTW phenotype and insulin resistance.

Prevalence and relationship of hypertriglyceridaemic-waist phenotype and type 2 diabetes mellitus among a rural adult Chinese population

OBJECTIVE

Limited information is available on the prevalence and effect of hypertriglyceridaemic-waist (HTGW) phenotype on the risk of type 2 diabetes mellitus (T2DM) in rural populations.

DESIGN

In the present cross-sectional study, we investigated the prevalence of the HTGW phenotype and T2DM and the strength of their association among rural adults in China.

SETTING

HTGW was defined as TAG &gt;1·7 mmol/l and waist circumference (WC) ≥90 cm for males and ≥80 cm for females. Logistic regression analysis yielded adjusted odds ratios (aOR) relating risk of T2DM with HTGW.ParticipantsAdults (n 12 345) aged 22·83-92·58 years were recruited from July to August of 2013 and July to August of 2014 from a rural area of Henan Province in China.

RESULTS

The prevalence of HTGW and T2DM was 23·71 % (males: 15·35 %; females: 28·88 %) and 11·79 % (males: 11·15 %; females: 12·18 %), respectively. After adjustment for sex, age, smoking, alcohol drinking, blood pressure, physical activity and diabetic family history, the risk of T2DM (aOR; 95 % CI) was increased with HTGW (v. normal TAG and WC: 3·23; CI 2·53, 4·13; males: 3·37; 2·30, 4·92; females: 3·41; 2·39, 4·85). The risk of T2DM with BMI≥28·0 kg/m2, simple enlarged WC and simple disorders of lipid metabolism showed an increasing tendency (aOR=1·31, 1·75 and 2·32).

CONCLUSIONS

The prevalence of HTGW and T2DM has reached an alarming level among rural Chinese people, and HTGW is a significant risk factor for T2DM.

Association between the Hypertriglyceridemic Waist Phenotype and Prediabetes in Chinese Adults Aged 40 Years and Older

OBJECTIVE

To investigate the association between the hypertriglyceridemic waist (HTGW) phenotype and prediabetes in Chinese adults aged 40 years and older.

METHODS

12757 adults (4101 men and 8656 women) without diabetes or cardiovascular and cerebrovascular diseases, free of using lipid-modified agents, were enrolled in this cross-sectional study. The HTGW phenotype was defined as elevated serum triglyceride concentrations and enlarged waist circumference. A two-hour post 75 g oral glucose tolerance test was performed in all participants. Multiple logistic regression analysis was used to evaluate the relationship of the HTGW phenotype with prediabetes.

RESULTS

Individuals with the HTGW phenotype had a higher adjusted odds ratio (OR: 1.70; 95% CI: 1.48-1.95) of prediabetes than those without the phenotype. There existed a strong relationship of the HTGW phenotype with impaired glucose tolerance (IGT) (OR: 1.83; 95% CI: 1.57-2.13), but not with impaired fasting glucose (IFG) (OR: 0.87; 95% CI: 0.65-1.17). Only women with the HTGW phenotype are significantly associated with the combined IFG and IGT (OR: 1.83; 95% CI: 1.28-2.62).

CONCLUSIONS

The HTGW phenotype was a useful risk indicator and a practical screening tool to benefit in the early diagnosis and intervention for prediabetes, particularly for IGT and the combined IFG and IGT.

Genetic effects on hypertriglyceridemic waist phenotype: rs780094, rs10830963, rs151290, and rs972283 polymorphisms and the interactions between them and behavior risk factors

BACKGROUNDS

We aimed to evaluate the association of SNPs in GCKR, MTNR1B, KCNQ1, and KLF14 genes confirmed in previous studies and hapertriglyceridemic waist (HTGW) in Han Chinese, and assess the interactions between genes and behavior risk factors.

METHODS

We genotyped the single nucleotide polymorphisms (SNPs) for GCKR, MTNR1B, KCNQ1, and KLF14 gene were genotyped in 373 patients with HTGW and 466 normal healthy subjects. We used logistic regression to investigate the gene-gene, gene-behavior interactions for the risk of HTGW.

RESULTS

Among the 4 SNPs, the AG genotype of rs780094 was protective factor, whereas the recessive model of rs151290 was risk factor after adjusting for confounders. Stratified by sex, only for women, the recessive model of rs151290 was still significance. The significant synergies interactions between SNPs were found between rs780094 in GCKR and rs972283 in KLF14 and rs10830963 in MTNR1B, respectively; meanwhile, the antagonistic interaction was revealed for rs151290 and rs780094 only for women. For male, there were significant synergies interactions between rs780094, smoking and alcohol drinking; and antagonistic interaction was revealed between rs780094 and severe activity both for men and women.

CONCLUSIONS

GCKR and KLF14 genes play a significant role in risk of HTGW in a Han Chinese population.

Hypertriglyceridemia-waist and risk of developing type 2 diabetes: The Rural Chinese Cohort Study

Limited information is available on the effect of hypertriglyceridemia–waist (HTGW) combination and its dynamic status on the risk of type 2 diabetes mellitus (T2DM) in rural China. A cohort of 12,086 participants 18 to 92 years old was retained in this study. Kaplan-Meier analysis yielded the cumulative incidence of T2DM for each phenotype group (based on TG level and waist circumference [WC] at baseline). Cox regression yielded hazard ratios relating HTGW (based on TG level and WC at baseline and follow-up) to risk of developing T2DM. After a median follow-up of 6.0 years (71,432 person-years of follow-up), T2DM developed in 621 participants. For HTGW participants, the incidence of T2DM was 26.4/1000, 20.6/1000, and 21.9/1000 person-years for males, females, and overall, respectively. The adjusted HR for HTGW associated with T2DM was 7.63 (95% CI 4.32–13.49) for males and 7.75 (4.71–12.78) for females. Compared with consistent HTGW, with transformation from baseline HTGW to normal WC and normal triglycerides level at follow-up, the risk of developing T2DM was reduced by 75% and 78% for males and females. HTGW is a major risk factor for T2DM, but the risk could be reduced by improved triglycerides level and WC.

Hypertriglyceridemic waist - a simple clinical tool to detect cardiometabolic risk: comparison with harmonized definition of metabolic syndrome

With the increasing prevalence of obesity and especially abdominal obesity, a simple clinical tool is needed that identifies the cardiometabolic risk for cardiovascular disease and type 2 diabetes. The aim of our study was to evaluate a broad spectrum of metabolic variables and IMT in subjects with and without hypertriglyceridemic waist (HTGW) and compare it with the harmonized definition of metabolic syndrome (MS) with both a higher (MS-I) and lower waist circumference (MS-II) for Europids. We enrolled 607 asymptomatic dyslipidemic subjects (295 men and 312 women) into our cross-sectional study. The subjects with HTGW had an atherogenic lipid profile (significantly higher triglycerides, AIP, non-HDL-C, lower HDL-C and ApoA-1, and the women also higher TC and ApoB), increased markers of insulin resistance (insulin, HOMA, C-peptide, proinsulin), inflammation (hsCRP), thrombosis (fibrinogen, PAI-1), SBP and DBP, and lower adiponectin (p<0.05-0.001 for all). These risk factors were entirely similar in HTGW, MS-I and MS-II. Age-adjusted IMT was significantly higher only in the women with HTGW but this significance disappeared after further adjustment for TC, SBP, and smoking. Our results support the routine use of HTGW as a simple and inexpensive screening tool to detect subjects at increased cardiometabolic risk in clinical practice.

Utility of hypertriglyceridemic waist phenotype for predicting incident type 2 diabetes: The Isfahan Diabetes Prevention Study

Aim/Introduction

We evaluated the association between hypertriglyceridemic waist (HTW) phenotype and the risks of type 2 diabetes in an Iranian high‐risk population.

Materials and Methods

We analyzed 7‐year follow‐up data (n = 1,865) in non‐diabetic first‐degree relatives of consecutive patients with type 2 diabetes aged 30–70 years. The primary outcome was the diagnosis of type 2 diabetes based on repeated oral glucose tolerance tests. We used multiple logistic regressions to estimate the odds ratio (OR) for incident type 2 diabetes across four groups according to baseline fasting serum triglycerides (TG) level and waist circumference (WC): normal WC and normal TG, normal WC and high TG, enlarged WC and normal TG, and HTW (enlarged WC high TG).

Results

The HTW phenotype at baseline was associated with the incidence of type 2 diabetes. Those with HTW were 2.4‐fold (OR 2.36, 95% confidence interval 1.61–3.44), those with normal WC high TG were 1.9‐fold (OR 1.87, 95% confidence interval 1.29–2.70) and those with enlarged WC but normal TG were 2.8‐fold (OR 2.84, 95% confidence interval 1.96–4.13) more likely to develop type 2 diabetes than those with normal WC and normal TG.

Conclusions

These data provide further evidence that the HTW phenotype is a robust predictor of type 2 diabetes in high‐risk individuals in Iran, and the predictive power is not higher than that of simple enlarged WC and normal TG, emphasizing the importance of enlarged WC to the development of type 2 diabetes.

Association of the hypertriglyceridemic waist phenotype and type 2 diabetes mellitus among adults in China

AIMS/INTRODUCTION

To clarify the association of the hypertriglyceridemic waist phenotype and type 2 diabetes mellitus among adults in China.

MATERIALS AND METHODS

In the present case-control study, we included 1,685 patients with type 2 diabetes mellitus and 7,141 normal glucose-tolerant controls from the Henan Province of China in 2011. Elevated waist circumference (GW) was defined as ≥90 cm for men and ≥80 cm for women. Hypertriglyceridemia (HT) was defined as >1.7 m mol/L triglycerides (TG) level. The association of hypertriglyceridemic waist phenotype and type 2 diabetes mellitus was investigated by sex, body mass index, physical activity, and family history of diabetes.

RESULTS

Cases and controls differed in age, waist circumference (WC), weight, TG level, fasting glucose, body mass index, smoking status, diabetic family history, physical activity and hypertriglyceridemic waist phenotype (P < 0.05), but not alcohol drinking (P = 0.63). In the overall sample, as compared with the phenotype of normal TG level and normal WC (NTNW), normal TG level/enlarged WC (NTGW), elevated TG level/normal WC (HTNW) and elevated TG level/enlarged WC (HTGW) were associated with type 2 diabetes mellitus (odds ratio 4.14, 2.42 and 6.23, respectively). Only HTGW was consistently associated with risk of type 2 diabetes mellitus, with or without adjustment. The strongest relationship between HTGW and type 2 diabetes mellitus was for subjects with body mass index <24.0 kg/m(2) (odds ratio 6.54, 95% confidence interval 4.22-10.14) after adjustment for cofounding variables.

CONCLUSION

HTGW was stably and significantly associated with risk of type 2 diabetes mellitus in adult Chinese.

Genome- and epigenome-wide association study of hypertriglyceridemic waist in Mexican American families

BACKGROUND

There is growing interest in the hypertriglyceridemic waist (HTGW) phenotype, defined as high waist circumference (≥95 cm in males and ≥80 cm in females) combined with high serum triglyceride concentration (≥2.0 mmol/L in males and ≥1.5 mmol/L in females) as a marker of type 2 diabetes (T2D) and cardiovascular disease. However, the prevalence of this phenotype in high-risk populations, its association with T2D, and the genetic or epigenetic influences on HTGW are not well explored. Using data from large, extended families of Mexican Americans (a high-risk minority population in the USA) we aimed to: (1) estimate the prevalence of this phenotype, (2) test its association with T2D and related traits, and (3) dissect out the genetic and epigenetic associations with this phenotype using genome-wide and epigenome-wide studies, respectively.

RESULTS

Data for this study was from 850 Mexican American participants (representing 39 families) recruited under the ongoing San Antonio Family Heart Study, 26 % of these individuals had HTGW. This phenotype was significantly heritable (h (2) r = 0.52, p = 1.1 × 10(-5)) and independently associated with T2D as well as fasting glucose levels and insulin resistance. We conducted genome-wide association analyses using 759,809 single nucleotide polymorphisms (SNPs) and epigenome-wide association analyses using 457,331 CpG sites. There was no evidence of any SNP associated with HTGW at the genome-wide level but two CpG sites (cg00574958 and cg17058475) in CPT1A and one CpG site (cg06500161) in ABCG1 were significantly associated with HTGW and remained significant after adjusting for the closely related components of metabolic syndrome. CPT1A holds a cardinal position in the metabolism of long-chain fatty acids while ABCG1 plays a role in triglyceride metabolism.

CONCLUSIONS

Our results reemphasize the value of HTGW as a marker of T2D. This phenotype shows association with DNA methylation within CPT1A and ABCG1, genes involved in fatty acid and triglyceride metabolism. Our results underscore the importance of epigenetics in a clinically informative phenotype.