Research Commentary [1] December 2016

Dec 1, 2016

This edition highlights the rapidly increasing prevalence of diabetes in the Asia Pacific region and ethnic inequalities in 30-day ischaemic stroke survival rates for Asian groups in New Zealand. Longer length of residence in New Zealand is associated with higher mortality rates for Asian peoples. Asian overseas born subgroups have about 70% of the mortality rate of their New Zealand born Asian counterparts, with little variation by Asian subgroup or cause of death. We need to understand the mechanisms of acculturation and the worsening of health with increased time spent in New Zealand in order to reduce mortality rates for Asian groups. The international studies included in this review, indicate effective lifestyle approaches to improving chronic conditions, such as osteoarthritis, obesity and diabetes (Wang et al., 2016; Welsh et al., 2016). With Asian populations now 25 percent of the Auckland region’s population, closer attention needs to be paid to addressing areas such as: improving targeted public health interventions to reduce CVD/Diabetes, and better access to in-hospital services to treat stroke once it has occurred. These areas don’t appear to be working for Asian groups.

Commentary provided by Dr Annette Mortensen, eCALD® Project Manager: Research and Development.

The following are articles reviewed:

Diabetes in the Asia Pacific Region

The prevalence of diabetes is rapidly increasing throughout the Asia Pacific region. In China, the epidemic of diabetes and related noncommunicable diseases will result in a huge burden on the health system. Diabetes is at the centre of a complex web of causation where the most important immediate factor appears to be an increase in individual and community obesity. The web stretches back to the first “1000 days of life,” including infant feeding patterns and epigenetics. Alteration of the human microbiome by adverse events in early life, including the use of infant formula and antibiotic exposure, plays an important role.

While type 2 diabetes is highly prevalent in obese populations in the Asia-Pacific region, it is also increasing rapidly in populations, such as in South Asia, where undernutrition is still prevalent and the people are generally regarded as “thin.” This suggests that the aetiology could involve more than increased fat storage and insulin resistance. The changing world diet and the promotion of high-energy “fast foods” are a part of the obesogenic environment in our region that will require public health intervention if progress is to be made.

Authors: Binns C et al.

Reference: Asia Pacific Journal of Public Health | 2016, Vol. 28(6) 472-474 @2016 APJPH


Are ethnic inequalities in 30-day ischaemic stroke survival emerging as treatment becomes more effective?

Studies of ethnic differences in stroke survival have produced inconsistent findings. As treatment becomes more effective, inequalities may increase. Ethnic differences in incidence and mortality from ischaemic stroke have been well documented both in New Zealand and elsewhere. Some of this excess can be explained by a higher prevalence of cerebrovascular risk factors, including obesity, diabetes, and hypertension. However, there is little evidence, that socially-disadvantaged ethnic groups have worse stroke survival or functional outcomes. In the US, case fatality rates (CFRs) for stroke in black Americans are similar to those in whites.

The aim of this study was to examine time trends in ischaemic stroke case fatality in New Zealand. The study found that ethnic inequalities in 30-day ischaemic stroke survival have increased significantly in the last 10 years. This may be due to differences in severity at presentation, or in access and utilisation of the increasingly effective acute and hyper-acute stroke interventions.

Authors: Sandiford P et al.

Reference: N Z Med J. 2016 Jul 1;129(1437):8-14.


Does Mortality Vary between Asian Subgroups in New Zealand: An Application of Hierarchichal Bayesian Modelling

This New Zealand study demonstrated that there is marked difference in mortality rates between Asian subgroups and between overseas born and New Zealand born Asian groups. Indian Asians exhibited the highest standardised all-cause mortality rates of any subgroup, followed by the other Asian and Chinese Asians. The study found evidence of the negative impact of acculturation. However, the study also showed that the health advantage of immigrant Asian subgroups varied depending upon subgroup ethnicity, cause of death, and duration of residence, reinforcing the need that these groups should be treated separately. Indian Asians had the lowest cancer mortality rates and highest CVD mortality rates. Aggregating these diverse and heterogeneous groups risks masking subgroup (and cause of death) differences in health outcomes and inappropriately targeting services and funds. Future research on the exact mechanisms of the worsening of health with increased time spent in a host country would improve the understanding of the process and would assist the policy-makers and health planners.

Authors: Jatrana S et al.

Reference: PLOS ONE | August 2014 | Volume 9 | Issue 8 | e105141


Comparative Effectiveness of Tai Chi versus physical therapy for knee osteoarthritis

This study is the first randomized comparative-effectiveness and cost-effectiveness trial of Tai Chi versus Physical Therapy in a large symptomatic knee osteoarthritis population with long-term follow up. The objective of the study was to compare Tai Chi with standard physical therapy for patients with knee osteoarthritis.

The authors present a robust and well-designed randomized comparative-effectiveness trial that also explores multiple outcomes to elucidate the potential mechanisms of the mind-body effect for a major disabling disease with substantial health burdens and economic costs.

Tai Chi produced beneficial effects similar to those of a standard course of physical therapy in the treatment of knee osteoarthritis. Of note, the Tai Chi group had significantly greater improvements in depression and the physical component of the quality of life. The results of this study have important public health implications for the large and growing population with knee osteoarthritis.

Authors: Wang C et al.

Reference: Ann Intern Med. 2016;165(2):77-86.


Associations between weight change and biomarkers of cardiometabolic risk in South Asians: secondary analyses of the PODOSA Trial

People of South Asian origin are at increased risk of type 2 diabetes over the full range of body mass indices (BMI), and when living in high-income countries such as the UK, are at higher risk compared to those of European origin. As such, existing clinical guidelines for the prevention of diabetes have emphasised the importance of targeting lower BMI in this group to lower this elevated risk. However, clinical trials involving lifestyle interventions have generally only had very modest effects in reducing obesity among South Asians. The Prevention of Diabetes and Obesity in South Asians (PODOSA) study of 171 South Asians with impaired glucose tolerance or impaired fasting glucose recently reported that the group who received a culturally adapted lifestyle intervention lost an adjusted mean difference of 1.64kg in weight and 1.89cm in waist circumference, compared to the control group (Bhopal et al., 2014; Wallia et al., 2013). This study demonstrates that a modest decrease in weight was associated with favourable changes in markers in several domains of cardiometabolic risk. Future trials with more intensive weight change are needed to extend these findings.

Authors: Welsh P et al.

Reference: International Journal of Obesity (1 March 2016) | doi:10.1038/ijo.2016.35


Ethnic inequalities in stroke: improvements not fast enough for everyone

For New Zealand Europeans, ischaemic stroke case fatality rates (CFR) are falling but rates have not improved significantly in Asian groups and the differences appear to be increasing. Age at stroke onset remains a glaring indication of the inequalities in stroke in New Zealand: average age at stroke onset in Auckland in 2012 was 75.3 years in New Zealand Europeans, compared with 67.5 in Asian/other ethnic groups. Public health efforts to prevent stroke and in-hospital efforts to treat stroke once it has occurred don’t appear to be working for Asian groups. More questions need to be asked such as: What are the details of ethnic variation in stroke care access, and what are the barriers that we can target to overcome these? Will the “FAST” campaign be effective in raising awareness of stroke for all New Zealanders, or some ethnicities more than others? As Fink (2016) says we need to ask, and answer these questions then act on them—fast.

Authors: Fink J

Reference: N Z Med J. 2016 Jul 1;129(1437):6-7.