Summary
Only four studies, all specifically involving South Asian communities alone, met eligibility criteria. Lack of controls in three, as well as inconsistency in measures and outcomes, meant it was not possible to pool data in a meta-analysis; as a result of this, firm conclusions about the effectiveness of the interventions that were assessed cannot be made. However, several insights and common themes can be offered from this review to inform future intervention development and research.
In relation to clinical outcomes, all programmes with combined physical activity and dietary change components reported decreases in weight where measured, but where the results were analysed by sex, changes in weight, waist circumference, and body and abdominal fat, these were only significant for men.22 The sex difference could relate to South Asian women from a variety of religious backgrounds being deterred from attending mixed-sex activities27 but, as programme engagement data were not provided, this cannot be ascertained. Mixed results were found for other clinical outcomes, with some reduction in blood pressure and blood lipid profiles, but no improvement, for example, in insulin sensitivity or resistance.
Participants in one study appeared to change dietary and activity patterns, but reliability of these behavioural outcomes was limited by use of single-item measures and self-reporting. Support for the efficacy of improving dietary knowledge was weak and no study measured knowledge of physical activity. One study suggested its community-based programme may encourage participants to progress through motivational stages of change,21 but this was reported in relation to general risk rather than specific behaviours.
Factors contributing to intervention engagement and acceptability
The involvement of trained bilingual community link workers appeared key to enhancing intervention acceptability and delivery in those studies that involved participants who were socially disadvantaged; for example, those from Pakistani and Bangladeshi communities, with significant proportions of participants across studies speaking little or no English.23,24 Qualitative feedback confirmed that, in addition to language skills, link workers were valued for their sensitivity and cultural understanding, which may have facilitated more meaningful and personal engagement in programmes. This finding is consistent with previous research suggesting that establishing relationships is important to the receptivity of lifestyle interventions in primary care.28
Programmes that were also promoted in the community and recruited by word of mouth appeared to generate more positive outcomes than those initiated from more formal healthcare settings, such as hospitals or clinics. Generating interest through local-community resources appeared to be beneficial due to the familiarity of the setting and the informal, social element of the meetings.23
Most programmes offered some form of personalised feedback, either in the form of one-to-one consultations or measurements of individual progress. This approach seemed to be potentially promising when accompanied by visual aids and handouts.21 Pictures and other visual aids were also valued and may help to overcome language and literacy barriers.22
Implications for research and practice
Many intervention studies that were identified had, or may have, included South Asian participants who were historically immigrant, but experiences that were distinguishable for South Asian individuals were not reported; as a result, only four studies met review criteria. Potentially important insights for enhancing appropriateness and implementation of interventions may be missed if relevant data are not reported when South Asian individuals are part of study populations. In addition to outcomes, information about participants’ engagement, language abilities, and social demographic, including deprivation and education status, may enable assessment of relevance and transferability. This is particularly pertinent for those South Asian communities that are more disadvantaged and at higher risk, where effective interventions are most needed and evidence is lacking.17
Three of the four studies reviewed appeared to have benefited from some prior qualitative work with target communities to inform intervention components; this may have been important to enhancing their acceptability.17,29 However, the quality of outcome data in the studies reviewed was generally poor, with a failure to consider potential confounders or adverse effects, and a lack of formal statistical-significance testing. All studies had flaws in internal validity, due to a lack of concurrent controls and data concerning programme compliance. Another common problem was a lack of standardised measures, particularly for behavioural, psychological, and knowledge-based outcomes. The majority of these measures lacked clear definition and appeared to be purpose designed, with no data available on piloting outcomes, validity, or reliability. Where possible, objective measures of behaviour, using standardised scales that have been validated in South Asian populations, are needed alongside clinical measures, as maintained behaviour change is necessary for sustained clinical benefit.
The importance of theoretical frameworks for evaluating complex interventions is increasingly recognised,29 but none of the studies designed their intervention with this in mind. Improving the effectiveness of lifestyle interventions requires an understanding of the causal techniques and procedures responsible for change.30 In the absence of a clear evidence base, progress is likely to be slow, with ‘wheels’ being reinvented rather than reapplied. All studies but one failed to measure the motivation of participants to change their lifestyles, which may account for the relative lack of intervention effects. Greater emphasis on combining targeted information with appropriate motivational techniques and specific behavioural guidance is needed. In addition, interventions may have been time and resource intensive in these studies, but no economic evaluation data were provided.
This review highlights a dearth of well-evaluated, community-based, physical activity, and dietary interventions for South Asian populations. Nevertheless, programmes were well received, suggesting that the potential to enhance physical activity and promote dietary change in these communities is considerable. Interventions that were reviewed may have resulted in some initial effects on health outcomes and offer useful first steps for enhancing health promotion in this group, which is at high risk of developing chronic disease. However, there remains much to be done to impact disease risk or morbidity, given the sustained and highly intensive interventions necessary to achieve this in other populations that are at risk. 9,10,13
Further research should focus on developing interventions that:
are informed by prior qualitative work with target communities;
incorporate a theoretical framework;
employ a robust methodology, with standardised and objective measures;
target education and behavioural motivation; and
provide a comparison group to assess effectiveness when naturally occurring change is controlled.
Approaches, particularly for South Asian populations that are socio-educationally deprived, may usefully build on current experience by using community-based programmes in a familiar environment with trained, bilingual community link workers. Interventions that include feedback and audiovisual media seem to be well received. Health–economic analyses should be performed alongside future experimental studies to ensure that promising preventative health programmes in these high-risk groups are cost effective and can be feasibly implemented.
