Effects of dietary and physical activity interventions on the risk of type 2 diabetes in South Asians: meta-analysis of individual participant data from randomised controlled trials

AIMS/HYPOTHESIS

Individuals of South Asian origin have a high risk of type 2 diabetes and of dying from a diabetes-attributable cause. Lifestyle modification intervention trials to prevent type 2 diabetes in high-risk South Asian adults have suggested more modest effects than in European-origin populations. The strength of the evidence of individual studies is limited, however. We performed an individual participant data meta-analysis of available RCTs to assess the effectiveness of lifestyle modification in South Asian populations worldwide.

METHODS

We searched PubMed, EMBASE, Cochrane Library and Web of Science (to 24 September 2018) for RCTs on lifestyle modification interventions incorporating diet and/or physical activity in South Asian adults. Reviewers identified eligible studies and assessed the quality of the evidence. We obtained individual participant data on 1816 participants from all six eligible trials (four from Europe and two from India). We generated HR estimates for incident diabetes (primary outcome) and mean differences for fasting glucose, 2 h glucose, weight and waist circumference (secondary outcomes) using mixed-effect meta-analysis overall and by pre-specified subgroups. We used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system to rate the quality of evidence of the estimates. The study is registered with the International Prospective Register of Systematic Reviews ([PROSPERO] CRD42017078003).

RESULTS

Incident diabetes was observed in 12.6% of participants in the intervention groups and in 20.0% of participants in the control groups. The pooled HR for diabetes incidence was 0.65 (95% CI 0.51, 0.81; I² = 0%) in intervention compared with control groups. The absolute risk reduction was 7.4% (95% CI 4.0, 10.2), with no interactions for the pre-specified subgroups (sex, BMI, age, study duration and region where studies were performed). The quality of evidence was rated as moderate. Mean difference for lifestyle modification vs control groups for 2 h glucose was -0.34 mmol/l (95% CI -0.62, -0.07; I² = 50%); for weight -0.75 kg (95% CI -1.34, -0.17; I² = 71%) and for waist -1.16 cm (95% CI -2.16, -0.16; I² = 75%). No effect was found for fasting glucose. Findings were similar across subgroups, except for weight for European vs Indian studies (-1.10 kg vs -0.08 kg, p = 0.02 for interaction).

CONCLUSIONS/INTERPRETATION

Despite modest changes for adiposity, lifestyle modification interventions in high-risk South Asian populations resulted in a clinically important 35% relative reduction in diabetes incidence, consistent across subgroups. If implemented on a large scale, lifestyle modification interventions in high-risk South Asian populations in Europe would reduce the incidence of diabetes in these populations.

Dietary and physical activity recommendations to prevent type 2 diabetes in South Asian adults: A systematic review

Intervention trials and guidelines for the prevention of type 2 diabetes (T2D) in populations of South Asian origin often include strategies to improve diet and physical activity that are based on those developed for other populations. These may be suboptimal for the South Asian target populations. We aimed to provide an overview of included recommended dietary and physical activity components, and to identify whether these were supported by evidence of their effectiveness. Databases were searched until September 2017 for intervention studies and guidelines with an adult South Asian population without T2D. The protocol was registered in PROSPERO, registration number: CRD42015207067. The quality of included studies and guidelines was assessed. Dietary and physical activity components, and effects on T2D incidence, glycemic status and adiposity measures, were summarized in tabular format and evaluated narratively. Eighteen intervention studies and four guidelines were identified. Dietary and physical activity components were similar to recommendations for the general population. Intervention studies and guidelines did not reference evidence to support the effectiveness of components included in the intervention for South Asian populations in particular. Moreover, we were unable to assess patterns of components to determine the effects of specific components. Evaluation of current and emerging components among South Asian populations and subgroups seems necessary to formulate more specific recommendations in future intervention studies and guidelines.

Dietary and physical activity strategies to prevent type 2 diabetes in South Asian adults: protocol for a systematic review

INTRODUCTION

Type 2 diabetes (T2D) is a major health concern among populations of South Asian ethnicity. Although dietary and physical activity interventions may reduce the risk of T2D, the effectiveness has been moderate among South Asians. This might (in part) be because this subgroup follows strategies that were originally developed for interventions among other populations. Therefore, this review aims to assess the evidence for the current dietary and physical activity strategies recommended in T2D prevention intervention studies and guidelines for South Asians.

METHODS AND ANALYSIS

Included will be all studies and guidelines on dietary and/or physical activity strategies to prevent T2D in adult South Asians. Two reviewers will search online databases from their start until the present date for published and unpublished experimental/quasiexperimental studies, with at least an abstract in English. References of identified articles and key reviews will be screened for additional studies. Guidelines will be identified by searches in online databases and websites of public organisations. Finally, expert consultations will be held to supplement any missing information. Trial quality will be assessed with the Quality Assessment Tool for Quantitative Studies Data, and guidelines with the Appraisal of Guidelines for Research & Evaluation II. Data on the strategies recommended, targeting and evidence on effectiveness will be extracted by two reviewers and presented in tabular and narrative forms. Recommendations will be compared with the National Institute for Health and Care Excellence guidelines [PH35]. Overall findings on dietary and physical activity recommendations, as well as findings for specific subgroups (eg, by sex), will be discussed.

ETHICS AND DISSEMINATION

Ethics assessment is not required. Start date: 1 January 2016, finishing and reporting date 31 July 2016. Results will be published in a peer-reviewed scientific journal, the project report of EuroDHYAN (www.eurodhyan.eu) and in a PhD dissertation.

TRIAL REGISTRATION NUMBER

The protocol is registered with the International Prospective Register of Systematic Reviews (PROSPERO) registration number CRD42015027067.

Prevalence and incidence of diabetes mellitus: a nationwide population-based pharmaco-epidemiological study in Sweden

AIM

To investigate the changes in prevalence and incidence of pharmacologically and non-pharmacologically treated diabetes in Sweden during 2005 to 2013.

METHODS

We obtained data on gender, date of birth and pharmacologically and non-pharmacologically treated diabetes from national registers for all Swedish residents.

RESULTS

During the study period a total of 240 871 new cases of pharmacologically treated diabetes was found. The age-standardized incidence during the follow-up was 4.34 and 3.16 per 1000 individuals in men and women, respectively. A decreasing time trend in incidence for men of 0.6% per year (0.994, 95% CI 0.989-0.999) and for women of 0.7% per year (0.993, 95% CI 0.986-0.999) was observed. The age-standardized prevalence increased from 41.9 and 29.9 per 1000 in 2005/2006 to 50.8 and 34.6 in 2012/2013 in men and women, respectively. This corresponds to an annually increasing time trend for both men (1.024, 95% CI 1.022-1.027) and women (1.019, 95% CI 1.016-1.021). The total age-standardized prevalence of pharmacologically and non-pharmacologically treated diabetes (2012) was 46.9 per 1000 (55.6 for men and 38.8 for women). This corresponds to an annually increasing time trend (2010-2012) for both men (1.017, 95% CI 1.013-1.021) and women (1.012, 95% CI 1.008-1.016).

CONCLUSIONS

The prevalence of pharmacologically treated diabetes increased moderately during 8 years of follow-up, while the incidence decreased modestly. This is in contrast to the results reported by most other studies. The total prevalence of diabetes (both pharmacologically and non-pharmacologically treated) in Sweden is relatively low, from a global viewpoint.

Culturally Specific Tobacco Use and South Asians in the United States

Over the past two decades, the United States has attracted large South Asian populations, who have imported tobacco products previously unique to the native subcontinent. South Asian cigarette use prevalence is consistently lower than other U.S. Asian subgroups; however, most surveys fail to capture smokeless products accurately. In part because of the pervasive use of popular smokeless cultural products resulting in greater population attributable risk of oral malignancies, many countries outside the United States have developed surveillance systems to capture these products and implemented effective population-level or community-based intervention strategies. This minority population in the United States continues to be “at risk” of suffering from a disproportionate burden of diseases, which are plausibly linked to the use of these products. The primary focus of this article is to provide an exhaustive literature review of tobacco use patterns and existing tobacco control strategies among South Asians in the United States. Framed within the social ecological model, the article suggests that there needs to be more detailed assessment of cultural tobacco products, a concurrent increase in cultural competencies of health care providers and provision of cessation resources outside the clinical setting. At the policy level, future efforts should adequately regulate these products and oversight must include such products in efforts to reduce rates of use. Concurrently, community-based efforts are needed to change social norms related to perceived health benefit and lack of stigma. This will help ensure that appropriately framed messages around use rates and burden of disease are addressed through culturally valued institutions and leaders.

A four-stage model explaining the higher risk of Type 2 diabetes mellitus in South Asians compared with European populations

With approximately 1.5 billion people at risk, the staggeringly high risk of Type 2 diabetes in South Asians comprises a global problem. The causes of this high risk are complex, with 23 major risk factors identified in a Lancet seminar. This paper proposes a four-stage explanatory model: (1) the birth of a small, adipose, lowlean mass South Asian baby--the phenotype tracking through life; (2) in childhood and early adulthood, the deposition of any excess energy intake preferentially in upper body and ectopic fat stores rather than in the lower body or superficial subcutaneous fat stores; (3) as a consequence of points 1 and 2, and exacerbated by an environment of low physical activity and excess calories, the accelerated appearance of high levels of plasma insulin, triglycerides and glucose, and the fatty-liver vicious cycle; (4) β-cell failure as a result of fewer β-cells at birth, exposure to apoptotic triggers such as fat in the pancreas, and high demand from insulin resistance, which causes diabetes. Other risk factors--especially energy-dense hyperglycaemic diet and low physical activity--play into this pathway. The recommended behavioural changes fit with this model, which brings clarity to guide future research, policy, practice and health promotion.

Primary prevention of Type 2 diabetes in South Asians--challenges and the way forward

Preventing diabetes is of enormous value, particularly for the South Asian countries, which have a huge healthcare burden from the onslaught of the disease. Type 2 diabetes has been proved to be preventable using lifestyle changes, even in South Asians despite their heightened risk profile. Strategies to improve awareness about diabetes and translation of preventive measures by innovative, culturally specific programmes have to be implemented at national levels. Integrated involvement of the government, community, media, healthcare and education services, and financial support from national and international organizations, are required. South Asian countries have initiated national programmes for diabetes prevention and management. It is also encouraging to note that joint ventures between developed countries such as the USA, UK and other European countries and centres of excellence in South Asia have been initiated to develop large-scale, community-oriented, pragmatic intervention strategies.

Efficacy and safety of saxagliptin in drug-naïve Asian patients with type 2 diabetes mellitus: a randomized controlled trial

BACKGROUND

Few studies have assessed the use of new oral anti-diabetic agents in Asian populations. This study assesses the efficacy and safety of saxagliptin versus placebo in Asian patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Five hundred sixty-eight drug-naïve adult patients with T2DM and glycated haemoglobin levels (HbA(1c)) of 7.0-10.0% (53-86 mmol/mol) were randomized 1 : 1 to receive saxagliptin 5 mg daily or placebo. Efficacy endpoints included changes from baseline to week 24 in HbA(1c) , fasting plasma glucose (FPG), post-prandial glucose area under the curve from 0 to 180 min (PPG AUC(0-180)), and the proportion of patients achieving HbA(1c) <7.0% (53 mmol/mol). Adverse events (AEs) and serious AEs (SAEs) were evaluated.

RESULTS

Saxagliptin provided statistically significant adjusted mean decreases from baseline to week 24 compared with placebo, respectively, in HbA(1c) (-0.84% [-9 mmol/mol] versus -0.34% [-4 mmol/mol]; p < 0.0001), FPG (-0.90 versus -0.17 mmol/L; p < 0.0001), and PPG AUC(0-180) (-417 versus -235 mmol · min/L; p = 0.0010). A significantly greater proportion of patients achieved a therapeutic glycaemic response (HbA(1c) <7.0% [53 mmol/mol]) with saxagliptin (45.8%) versus placebo (28.8%; p < 0.0001). The proportions of patients who experienced ≥1 AE (excluding hypoglycaemia) was 43.3% for saxagliptin and 35.6% for placebo. Few patients in either treatment group experienced an SAE (2.8%, saxagliptin; 1.4%, placebo). A low proportion of patients reported hypoglycaemic events (1.8%, saxagliptin; 0.7%, placebo).

CONCLUSIONS

Saxagliptin improved glycaemic control and was well tolerated in drug-naïve Asian patients with T2DM.

Nutrition-related health management in a Bangladeshi community

The British Bangladeshi community is one of the youngest and fastest growing ethnic minority groups in the UK. Many report poor socio-economic and health profiles with the existence of substantial health inequalities, particularly in relation to type 2 diabetes. Although there is compelling evidence for the effectiveness of lifestyle interventions in the prevention of type 2 diabetes, there is little understanding of how best to tailor treatments to the needs of minority ethnic groups. Little is known about nutrition related lifestyle choices in the Bangladeshi community or the factors influencing such decisions. Only by exploring these factors will it be possible to design and tailor interventions appropriately. The Bangladeshi Initiative for the Prevention of Diabetes study explored lay beliefs and attitudes, religious teachings and professional perspectives in relation to diabetes prevention in the Bangladeshi community in Tower Hamlets, London. Contrary to the views of health professionals and previous research, poor knowledge was not the main barrier to healthy lifestyle choices. Rather the desire to comply with cultural norms, particularly those relating to hospitality, conflicted with efforts to implement healthy behaviours. Considerable support from Islamic teachings for diabetes prevention messages was provided by religious leaders, and faith may have an important role in supporting health promotion in this community. Some health professionals expressed outdated views on community attitudes and were concerned about their own limited cultural understanding. The potential for collaborative working between health educators and religious leaders should be explored further, and the cultural competence of health professionals addressed.

High-sensitivity C-reactive protein levels and type 2 diabetes in urban North Indians

CONTEXT

Elevated high-sensitivity C-reactive protein (hsCRP) levels have frequently been shown to be associated with type 2 diabetes (T2D); however, very little is known about this in Asian Indians, a high-risk group.

OBJECTIVE

The aim of the study was to assess the association of hsCRP with T2D and to determine its correlates in North Indians of Indo-European origin.

DESIGN AND PATIENTS

A cross-sectional population-based study of 2520 urban subjects, comprising 1410 T2D patients and 1110 nondiabetic subjects, was carried out and 18 metabolic traits were assessed.

RESULTS

Median hsCRP levels were significantly higher in both diabetic men and women as compared to their nondiabetic counterparts (P < 0.0001). Elevated hsCRP was positively associated with T2D (odds ratio, 1.66; 95% confidence interval, 1.21-2.28; P = 0.002) even after adjusting for markers of obesity. After adjustments for age, sex, and BMI, HbA1c was the major correlate of hsCRP in nondiabetic subjects (beta = 0.28; P = 0.03). We observed that T2D patients were at higher risk for cardiovascular disease compared to nondiabetic subjects when classified into low-, intermediate-, and high-risk groups based on hsCRP levels (p(trend) = 3.8 x 10(-15)).

CONCLUSIONS

We demonstrate the association of low-grade systemic inflammation, as indicated by elevated hsCRP levels, with T2D in North Indian population. This association was independent of obesity. Obesity and glycemic control were the major correlates of hsCRP levels. Future studies are required to evaluate the influence of modulators including genetic variations on the elevation of hsCRP levels in this population.