Hypertriglyceridemic waist and newly-diagnosed diabetes among remote-dwelling Indigenous Australians

A systematic review of the major risk factors for type two diabetes among Aboriginal Australians

BACKGROUND

To investigate the sociodemographic, anthropometric, biochemical, lifestyle and cardiometabolic risk factors associated with type 2 diabetes (T2D) among First Nations Australians.

METHODS

A systematic review of prospective cohorts and cross-sectional studies was conducted. Electronic data sources (MEDLINE/PubMed, Embase, CINHAL, and PsycINFO) were searched for peer-reviewed articles until August 2023. We reviewed observational and interventional studies on T2D that reported sociodemographic, anthropometric, lifestyle, and biochemical risk factors for Australian First Nations people. Narrative synthesis was applied without meta-analysis. We highlighted the major risk factors for T2D by reporting the most significant findings from individual studies in the results. The review followed PRISMA guidelines.

RESULTS

The review included 20 eligible studies: 12 cross-sectional studies and 8 prospective cohort studies. The findings from these studies showed that First Nations people who resided in very remote areas (Modified Monash Category 7; MM7) (OR = 1.61; 95% CI: 1.03, 2.52), living adjacent to food store stocking "Western" food items (OR = 2.92; 95% CI: 1.51, 5.63), rented their home (OR = 2.07; 95% CI: 1.30, 3.30) and part-time employment (OR = 2.47; 95% CI: 1.54, 3.95) were associated with a statistically higher risk of developing T2D. First Nations people who had obesity class 1 (BMI > 30 kg/m2), central obesity (WC > 88 cm in women; >102 cm in men), and higher waist-to-hip ratio (WHR) (≥ 1.0 in men and 0.85 in women) were more likely to have T2D. First Nations people with elevated triglycerides (≥ 1.7 mmol/L) (OR = 4.9; 95% CI: 2.7, 8.8), one standard deviation (SD) increase in C-reactive protein (CRP) value (AHR = 1.23; 95% CI: 1.05, 1.45) and lower levels of vitamin D (< 53 nmol/L) (AOR = 2.15; 95% CI: 1.10, 2.18) were significantly associated with a higher risk of T2D. However, no significant association was found with either daily smoking or daily alcohol.

CONCLUSION

To address the First Nations Health Gap attributed to T2D in Australia, interventions should prioritise remote areas, socioeconomic disadvantage, central obesity, elevated triglycerides, and vitamin D deficiency. This was the first comprehensive systematic review examining sociodemographic, anthropometric, biochemical, lifestyle, and cardiometabolic risk factors associated with T2D among First Nations Australians.

Antioxidant biomarkers and cardiometabolic risk markers in an Aboriginal community in remote Australia: a cross-sectional study

OBJECTIVE

High-quality diets, characterised by nutrient-rich foods, are one of the foundations for health and well-being. Indicators of diet quality, antioxidants, are associated with protection against cardiometabolic diseases. The current study explores relationships between plasma antioxidants and cardiometabolic risk among Aboriginal people in Australia.

DESIGN

As part of a community-driven health promotion programme, we conducted a cross-sectional study including a health-behaviour questionnaire, plasma antioxidants and cardiometabolic risk markers (anthropometric, blood pressure measurements, fasting glucose, glycated Hb (HbA1c), lipids, C-reactive protein and albumin-creatinine-ratio) continuous and categorised into population-specific cut-offs. Antioxidants (β-carotene, β-cryptoxanthin, lycopene, lutein-zeaxanthin, retinol and α-tocopherol measured using HPLC) were applied to a principal component analysis, which aggregated these into a single component. Linear regression models were applied to investigate associations between the antioxidant component and cardiometabolic risk markers.

SETTING

Community in a remote area in Northern Territory, Australia.

PARTICIPANTS

A total of 324 Aboriginal people, mean age 35·5 (range 15-75) years.

RESULTS

Antioxidant component levels were higher among individuals with higher self-reported vegetable intake (P < 0·01), higher among individuals with higher self-reported fruit intake (P = 0·05) and lower among current smokers (P = 0·06). Linear regression revealed an inverse association between the antioxidant component and C-reactive protein (β = -0·01, P < 0·01) after adjusting for confounders.

CONCLUSION

Higher plasma antioxidant levels, indicators of diet quality, were associated with lower levels of high-sensitivity C-reactive protein in this Aboriginal population in remote Australia. This association suggests plasma antioxidants may be protective against inflammation; however, longitudinal studies are needed to examine this potentially protective relationship.

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.

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.

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.

The Impact of Prior Flavivirus Infections on the Development of Type 2 Diabetes Among the Indigenous Australians

It is estimated that 5% of Australians over the age of 18 have diabetes, with the number of new cases increasing every year. Type 2 diabetes (T2D) also represents a significant disease burden in the Australian indigenous population, where prevalence is three times greater than that of non-indigenous Australians. Prevalence of T2D has been found to be higher in rural and remote indigenous Australian populations compared with urban indigenous Australian populations. Several studies have also found that body mass index and waist circumference are not appropriate for the prediction of T2D risk in indigenous Australians. Regional and remote areas of Australia are endemic for a variety of mosquito-borne flaviviruses. Studies that have investigated seroprevalence of flaviviruses in remote aboriginal communities have found high proportions of seroconversion. The family Flaviviridae comprises several genera of viruses with non-segmented single-stranded positive sense RNA genomes, and includes the flaviviruses and hepaciviruses. Hepatitis C virus (HCV) has been shown to be associated with insulin resistance and subsequent development of T2D. Flaviviruses and HCV possess conserved proteins and subgenomic RNA structures that may play similar roles in the development of insulin resistance. Although dietary and lifestyle factors are associated with increased risk of developing T2D, the impact of infectious diseases such as arboviruses has not been assessed. Flaviviruses circulating in indigenous Australian communities may play a significant role in inducing glucose intolerance and exacerbating T2D.

Prevalence of hypertriglyceridemic waist and association with risk of type 2 diabetes mellitus: a meta-analysis

INTRODUCTION

A meta-analysis of studies assessing the prevalence of hypertriglyceridemic waist and an association with risk of type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

PubMed, EMBASE, Web of Science, CNKI, CQVIP and Wanfang databases were searched for studies of the prevalence of hypertriglyceridemic waist or association with risk of T2DM. Reference lists of each original article were also searched. A random-effects model was used to synthesize the combined prevalence and odds ratios. Publication bias and substantial heterogeneity were examined.

RESULTS

Twenty-five eligible studies involving 93 194 participants (93 194 for prevalence and 34 199 for odds ratios): 17 articles of prevalence, and 8 of both prevalence and risk of T2DM. Prevalence of hypertriglyceridemic waist ranged from 4% to 47%, with pooled prevalence of 18% (95% CI 13-23%), overall: 18% (95% CI 13-23%) for men and 19% (95% CI 13-24%) for women. Odds ratios ranged from 2.8 to 9.6 for T2MD in overall, with pooled odds ratios of 4.18 (95% CI 3.55-4.92), overall: 3.55 (95% CI 2.93-4.31) for men and 4.18 (95% CI 3.43-5.09) for women.

DISCUSSION/CONCLUSION

The prevalence of hypertriglyceridemic waist has reached an alarming level and is closely associated with increased risk of T2DM in the general population, particularly among women and among brown-skinned men and women.

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.