Serum vitamin D levels, diabetes and cardio-metabolic risk factors in Aboriginal and Torres Strait Islander 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.

Indigenous Australians critically ill with sepsis: Characteristics, outcomes, and areas for improvement

BACKGROUND

Aboriginal and Torres Strait Islander Australians have amongst the highest incidence of sepsis globally.

OBJECTIVE

The objective of this study was to describe the characteristics, short- and long-term outcomes of non-Indigenous, Aboriginal Australian and Torres Strait Islander Australians admitted with sepsis to an intensive care unit (ICU) to inform healthcare outcome improvement.

METHODS

A retrospective cohort study of 500 consecutive sepsis admissions to the Cairns Hospital ICU compared clinical characteristics, short-term (before ICU discharge) and long-term (2000 days posthospital discharge) outcomes. Cohort stratification was done by voluntary disclosure of Indigenous status.

RESULTS

Of the 442 individual admissions, 145 (33%) identified as Indigenous Australian. Indigenous and non-Indigenous Australians had similar admission Acute Physiology and Chronic Health Evaluation-3 scores (median [interquartile range]: 70 [52-87] vs. 69 [53-87], P = 0.87), but Indigenous patients were younger (53 [43-60] vs. 62 [52-73] years, P < 0.001) and were more likely to have chronic comorbidities such as type 2 diabetes (58% vs. 23%, P < 0.001), cardiovascular disease (40% vs 28%, P = 0.01), and renal disease (39% vs. 10%, P < 0.001). They also had more hazardous healthcare behaviours such as smoking (61% vs. 45%, P = 0.002) and excess alcohol consumption (40% vs. 18%, P < 0.001). Despite this, the case-fatality rate of Indigenous and non-Indigenous Australians before ICU discharge (13% vs. 12%, P = 0.75) and 2000 days post hospital discharge (25 % vs. 28 %, P = 0.40) was similar. Crucially, however, Indigenous Australians died younger both in the ICU (median [interquartile range] 54 (50-60) vs. 70 [61-76], P < 0.0001) and 2000 days post hospital discharge (58 [53-63] vs. 70 [63-77] years, P < 0.0001).

CONCLUSIONS

Although Indigenous Australians critically ill with sepsis have similar short and long-term mortality rates, they present to hospital, die in-hospital, and die post-discharge significantly younger. Unique cohort characteristics may explain these outcomes, and assist clinicians, researchers and policy-makers in targeting interventions to these characteristics to best reduce the burden of sepsis in this cohort and improve their healthcare outcomes.

Prevalence and predictors of vitamin D deficiency in a nationally representative sample of Australian Aboriginal and Torres Strait Islander adults

Vitamin D deficiency (serum 25-hydroxyvitamin D (25(OH)D) concentration <50 nmol/l) is recognised as a public health problem globally. The present study details the prevalence and predictors of vitamin D deficiency in a nationally representative sample (n 3250) of Australian Aboriginal and Torres Strait Islander adults aged ≥18 years. We used data from the 2012-2013 Australian Aboriginal and Torres Strait Islander Health Survey (AATSIHS). Serum 25(OH)D concentrations were measured by liquid chromatography-tandem MS. Survey-weighted logistic regression models were used to determine the independent predictors of vitamin D deficiency. Approximately 27 % of adult AATSIHS participants were vitamin D deficient. Vitamin D deficiency was more prevalent in remote areas (39 %) than in non-remote areas (23 %). Independent predictors of vitamin D deficiency included assessment during winter (men, adjusted OR (aOR) 5·7; 95 % CI 2·2, 14·6; women, aOR 2·2; 95 % CI 1·3, 3·8) and spring (men, aOR 3·3; 95 % CI 1·4, 7·5; women, aOR 2·6; 95 % CI 1·5, 4·5) compared with summer, and obesity (men, aOR 2·6; 95 % CI 1·2, 5·4; women, aOR 4·3; 95 % CI 2·8, 6·8) compared with healthy weight. Statistically significant associations were evident for current smokers (men only, aOR 2·0; 95 % CI 1·2, 3·4), remote-dwelling women (aOR 2·0; 95 % CI 1·4, 2·9) and university-educated women (aOR 2·4; 95 % CI 1·2, 4·8). Given the high prevalence of vitamin D deficiency in this population, strategies to maintain adequate vitamin D status through safe sun exposure and dietary approaches are needed.

The role of vitamin D in prevention of type 2 diabetes. A meta-analysis

BACKGROUND AND AIMS

Recently, there are evidences that have shown vitamin D homeostasis has an impact in the development of type 2 diabetes. However, still it is unclear if vitamin D supplementation reduces the risk of overt diabetes. This meta-analysis of cross-sectional studies and RCTs was conducted to evaluate the role of vitamin D in prevention of type 2 diabetes and to elucidate this controversial topic.

METHODS

A systematic search for English-language literature was done via PUBMED/Medline and Google Scholar up to March 2020. Based on a fixed and random effects model, the OR, HR and 95% CI were used to evaluate the combined risk. This study followed Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) Guidelines.

RESULTS

After eligibility assessment 10 studies with a total of 34,882 participants were included in meta-analysis. Meta-analysis of cross-sectional studies suggested that there was a statistically significant association between the vitamin D and type 2 Diabetes; the pooled OR (95%CI) was 1.77 [1.51, 2.07] (P < 0.001). Meta-analysis of RCTs have shown that there was no statistically significant association between vitamin D supplementation and prevention of type 2 Diabetes, the pooled HR (95%CI) was 0.89 [0.77, 1.02] (P = 0.08).

CONCLUSION

In conclusion, this meta-analysis suggests that there is association between the vitamin D and type 2 diabetes. However, the result of RCTs suggests emphasis of future studies for genetic factors such as polymorphic variants of the VDR gene as one factor in this complex process.

Associations of Serum 25-Hydroxyvitamin D with Adiposity and At-Risk Lipid Profile Differ for Indigenous (Orang Asli) Male and Female Adults of Peninsular Malaysia

BACKGROUND

Low vitamin D status, adiposity, and at-risk lipid profile are associated with adverse health consequences. This study aimed to assess serum 25(OH)D concentration of Indigenous (Orang Asli) adults and to determine the associations between serum 25(OH)D with adiposity and lipid profile, respectively.

METHODS

This cross-sectional study was conducted among 555 (164 men, 391 women) Orang Asli adults aged 18-65 years of Jah Hut sub-tribe in Krau Wildlife Reserve (KWR), Peninsular Malaysia. Demographic and socio-economic information were obtained using interviewer-administered questionnaire. Participants were also assessed for serum 25-hydroxyvitamin D (25(OH)D) concentration, adiposity indices (BMI, WC, WHtR, WHR, %BF) and lipid parameters (TC, LDL-C, HDL-C, TG). Data were analyzed using binary logistic regression via SPSS.

RESULTS

The prevalence of suboptimal 25(OH)D concentration was 26.3%, comprising 24.9% insufficiency (50 to <75 nmol/L) and 1.4% deficiency (<50 nmol/L). While men (14-30.5%) were associated with a more proatherogenic lipid profile than women (6.1-14.3%), more women were with central obesity (M: 19.5-46.3%; F: 34.5-49.1%) and suboptimal (<75 nmol/L) vitamin D status (M: 11.6%; F: 32.4%). While suboptimal 25(OH)D concentration was significantly associated with higher odds of at-risk LDL-C (p < 0.01) and obesity (WC, WHtR) (p < 0.05) in men, no significant association was observed for women. Nonetheless, it should be noted that there were only 19 men with suboptimal (<75 nmol/L) vitamin D status.

CONCLUSIONS

While suboptimal vitamin D status was relatively low in Orang Asli adults, the prevalence of obesity and undesirable serum lipids were relatively high. The sex-specific associations between vitamin D status with adiposity indices and serum lipids warrant further investigation.

Seasonality of hip fracture and vitamin D deficiency persists in a sub-tropical climate

Both hip fractures and vitamin D (25-hydroxyvitamin D (25-OHD)) deficiency are more common in winter in regions with temperate climates, but few data exist for a sub-tropical climate. In a South East Queensland tertiary hospital over a 7-year period, there were significantly more hip fractures in winter than the other three seasons (analysis of variance P = 0.003), with associated higher frequency of 25-OHD deficiency - 42.5% in winter compared to 28.5% in summer, odds ratio 1.86 (95% confidence interval 1.35-2.56), P = 0.0001. Seasonality of hip fracture and 25-OHD deficiency occurs even in a sub-tropical climate.

Musculoskeletal health of Indigenous Australians

INTRODUCTION

Research on non-communicable diseases (NCD) in Indigenous Australians has mostly focused on diabetes mellitus and chronic kidney or cardiovascular disease. Osteoporosis, characterised by low bone mass and structural deterioration of bone tissue, and sarcopenia, the age-related loss of muscle mass and strength, often co-exist with these common NCDs-the combination of which will disproportionately increase bone fragility and fracture risk and negatively influence cortical and trabecular bone. Furthermore, the social gradient of NCDs, including osteoporosis and fracture, is well-documented, meaning that specific population groups are likely to be at greater risk of poorer health outcomes: Indigenous Australians are one such group.

PURPOSE

This review summarises the findings reported in the literature regarding the muscle and bone health of Indigenous Australians.

FINDINGS

There are limited data regarding the musculoskeletal health of Indigenous Australians; however, areal bone mineral density (aBMD) measured by dual-energy X-ray absorptiometry (DXA) is reported to be greater at the hip compared to non-Indigenous Australians. Falls are the leading cause of injury-related hospitalisations in older Australians, particularly Indigenous Australians, with a great proportion suffering from fall-related fractures. Despite sparse data, it appears that Indigenous men and women have a substantially higher risk of hip fracture at a much younger age compared to non-Indigenous Australians.

CONCLUSION

Data on more detailed musculoskeletal health outcomes are required in Indigenous Australians to better understand fracture risk and to formulate evidence-based strategies for fracture prevention and to minimise the risk of falls.

Low levels of Vitamin D an emerging risk for cardiovascular diseases: A review

Sunlight is regarded among greatest gifts that are presented in abundance to the human beings from the God. Sunlight is also a rich source of Vitamin D (Vit D) that prevents us from numerous ailments such as autoimmune disorders, various types of cancer, and the above all cardiovascular diseases (CVD). Evident from recent research that Vit D deficiency may be the cause for hypertension, cardiac autonomic imbalance, vascular endothelial dysfunction, metabolic syndrome, and even diabetes. Concurrently, many studies present research outcomes that are contradictory to earlier results and also raised a concern not for general public but also among their treating physicians. The sole focus of this review is to systematically present the available research data and critically evaluate the link between Vit D deficiency and development of risk factors for CVD.

Vitamin D-binding protein as it is understood in 2016: is it a critical key with which to help to solve the calcitriol conundrum?

Background The misnamed 'vitamin' D is actually the hormone calcitriol (1,25 dihydroxyhydroxyvitamin D). It has a central regulatory role in calcium metabolism, and more widely in the immune system. The prohormone calcifediol (25 hydroxyvitamin D) is more easily measured in the laboratory and is the analyte used in reference interval formulation. Being highly lipid soluble, both calcifediol and calcitriol travel in the bloodstream on carriage proteins, principally on vitamin D-binding protein. Summary This review reports our current understanding of vitamin D-binding protein. Its genetic determinants and their effect on it and secondarily on calcifediol concentrations and assays are described. Its complex interplay with parathyroid hormone is considered. The analytical state of the art is translated into the challenge it imposes clinically, in the formulation of reference intervals and in their use in advising and managing patients. Several recent challenges thrown up to laboratories by percipient clinicians highlight the dilemma vitamin D-binding protein poses. A way forward is suggested.

Hypovitaminosis D: a novel risk factor for coronary heart disease in type 2 diabetes?

Vitamin D (25(OH)D) levels have been associated with cardiovascular disease. Thus, the aim of our study was to investigate the association of 25(OH)D levels with coronary heart disease (CHD) in 698 consecutive type 2 diabetic outpatients. 698 consecutive type 2 diabetic outpatients (25.2 % men, age 66 ± 9 years) and 100 (90 % men, age 65 ± 13 years) age-matched non-diabetic volunteers were enrolled. 25(OH)D assay and the main cardiovascular risk factors were explored. 25(OH)D concentration was 22 ± 10 ng/ml in control subjects and 18.23 ± 10 ng/ml in diabetic patients (p < 0.01). The prevalence of hypovitaminosis D was higher in diabetic patients than in control subjects (90 vs. 83 %, p < 0.01). Diabetic subjects with hypovitaminosis D had higher prevalence of high values of A1C (p < 0.01), BMI (p < 0.01), LDL cholesterol (p < 0.01), triglycerides (p < 0.01), and glycemia (p < 0.01) than their vitamin D-sufficient counterparts. 25(OH)D and HDL cholesterol were lower (p < 0.01), while BMI (p < 0.01), age (p < 0.01), systolic (p < 0.01) and diastolic blood pressure (p < 0.01), diabetes duration (p < 0.01), A1C (p < 0.01), glycemia (p < 0.01), fibrinogen (p < 0.01), triglycerides (p < 0.01), and total (p < 0.01) and LDL cholesterol (p < 0.01) were higher in diabetic subjects with CHD than diabetic subjects without CHD. At the logistic regression analysis, the association of vitamin D with CHD was lost, while sex (p = 0.026), diabetes duration (p = 0.023), and age (p = 0.024) were the most powerful predictors of CHD. The current study demonstrates that 25(OH)D does not have a direct effect on CHD but may have an indirect effect mediated by cardiovascular risk factors such as diabetes duration, age, and sex.