Discussion
This study used mixed methods to plan, implement and test the feasibility of a lifestyle intervention programme for diabetes prevention for US South Asians. Formative qualitative research found that South Asian Americans report a high prevalence of unhealthy behaviours and felt that immigration, culturally prescribed gender roles and the role of food in their culture were significant barriers to making healthy lifestyle choices. Some participants used many of these same factors—particularly the importance of taking care of their family and the need to be healthy to fulfil this role—as motivating factors for making healthy changes. In a subsequent pilot intervention study, a lifestyle education programme based on the DPP successfully recruited and enrolled South Asian Americans and led to positive improvements in glycaemic status, anthropometry and plasma lipids. However, on-campus testing was a barrier to attending follow-up visits.
The SHAPE study supports research from UK, Canada and US South Asians describing the important role of food in South Asian culture,14 the prevalence of unhealthy dietary behaviours,15–20 and how migration changes lifestyle behaviours, resulting in weight gain and increased risk of diabetes.21–23 However, the ways that migration effects behaviour differs for South Asians in non-US settings; for example, in a study of South Asians in Australia, participants blamed poor eating habits and a move away from traditional home-cooked foods on underemployment, the necessity of dual-income households and eating cheaper, less healthy food options because of financial difficulties.24 Conversely, SHAPE participants discussed using fast foods because of the lack of cooking skills (for men) or because of limited vegetarian choices and an increase in potentially unhealthy ingredients (eg, sugar, oil) because they lower cost in the USA allowed participants to splurge.
South Asian society is pluralist,25–27 prioritising the needs of the community over self; it is perhaps unsurprising that participants reported that family responsibilities are the major barrier to increasing physical activity. Although SHAPE participants cited many of the same barriers to physical activity as other South Asian migrant studies (household or work responsibilities, little cultural focus on being active), SHAPE participants did not mention current health conditions as barriers to physical activity as has been reported elsewhere.28–31
Some of the differences in reported barriers and activities around lifestyle behaviours in the SHAPE population may be due to the relatively high education and socioeconomic status of participants. SHAPE focus group participants understood of the link between healthy diet, physical activity and chronic disease prevention, even if this knowledge did not translate into changed behaviours. In other studies, South Asian participants did not make the connection between lifestyle choices and disease risk or current disease status.24 29 32
DPPs for South Asians can use the same cultural influences that currently pose barriers to healthy lifestyle choices as forces of change. Participants in this and other studies24 28 30 33 reported that social support, particularly from family, was vital for starting and maintaining diet change and physical activity. Family was also a primary motivating factor for healthy lifestyle changes, and families that changed their lifestyles together were particularly successful.
There is limited research applying these and similar findings for diabetes prevention in South Asians. Outside of the USA, studies delivering the DPP or the Finish Diabetes Prevention Study curriculum have reported mixed, but largely positive impacts on glycaemic status with little effects on anthropometry.34–36 Two US studies of lifestyle programmes for reducing diabetes or cardiovascular risk reported improvements in glycaemic markers and in one study weight.37 38
Although the SHAPE pilot study was small and lacked good follow-up for study testing, it has promising results that support further testing of culturally tailored lifestyle intervention programs for the US South Asian population. Follow-up in study classes was good, with only two participants dropping out of the programme, and those who attended follow-up visits showed positive improvements in anthropometric markers such as body weight and more markedly, waist circumference. In the DPP, weight loss was the strongest predictor of diabetes risk reduction.39 Perhaps even more striking is that five of the nine participants at end of study testing had regressed to normoglycaemia; within the DPP, even transient regression to normal glucose levels was associated with a 56% reduction in diabetes risk.40
This study has several strengths. The formative and pilot trial data add to the small but growing literature on diabetes prevention and lifestyle behaviours among US South Asians. The FGDs included a large and diverse population of South Asian adults, including men and women with and without diabetes from various countries and regions of South Asia, of different religious traditions, and with a range of education levels. The results varied little between age and sex groups indicating that the barriers and motivating factors for diet and physical activity change are not patterned by standard demographic variables, but rather are stronger cultural issues seen in a diverse population of South Asian Americans. The pilot trial adds important information on the feasibility of translating proven DPPs to the South Asian Americas. This was the first study to our knowledge to report regression to normoglycaemia among South Asians enrolled in a diabetes prevention study, and SHAPE is one of the few studies of diabetes prevention among South Asians, enrolled participants across the pre-diabetes spectrum, and specifically targeted overweight and obese South Asians.
Nevertheless, this study has several limitations. The pilot study too small to enable significance testing of results and there was loss of participants at follow-up testing visits. The goal of the SHAPE intervention was to assess programme feasibility, however, and even with these significant hurdles, the study provided a better understanding of barriers to participation and possible effects of the programme on health outcomes. Recruitment logistics for FGDs made it impossible to recruit younger participants quickly enough to host separate groups for first and second-generation South Asians resulting in an inability to capture differences that place of birth might have on lifestyle behaviours. The results of this study may not apply to non-English-speaking South Asians. The researchers believe that this is not the case, since focus group participants described behaviours of the South Asian community more broadly and requested the programme in English, and the research team was able to recruit a sizeable population of older South Asians where English skills might be lowest. However, acculturation affects lifestyle behaviours such as diet and physical activity, and the researchers cannot rule out the possibility that English-speaking participants are more acculturated than other members of the South Asian community and that different interventions might be needed for South Asians with low-English proficiency.
Despite these limitations, the SHAPE study provides important information on the current behaviours, beliefs and feelings around diabetes prevention, diet change and physical activity, as well as pilot data showing the feasibility of a DPP-like intervention among South Asian Americans. Future work should focus on testing the SHAPE intervention in a larger trial, collecting more formalised feedback on programme acceptability and considering additional intervention models, a family-based programme, for instance, to address the high risk of diabetes in this community.