Effectiveness of prevention programmes for obesity and chronic diseases among immigrants to developed countries - a systematic review.

OBJECTIVE: To determine whether interventions tailored specifically to particular immigrant groups from developing to developed countries decrease the risk of obesity and obesity-related diseases.
DESIGN: Databases searched were MEDLINE (1966-September 2008), CINAHL (1982-September 2008) and PsychINFO (1960-September 2008), as well as Sociological Abstracts, PsychARTICLES, Science Direct, Web of Knowledge and Google Scholar. Studies were included if they were randomised control trials, 'quasi-randomised' trials or controlled before-and-after studies. Due to the heterogeneity of study characteristics only a narrative synthesis was undertaken, describing the target population, type and reported impact of the intervention and the effect size.
RESULTS: Thirteen studies met the inclusion criteria. Ten out of thirteen (77 %) studies focused on diabetes, seven (70 %) of which showed significant improvement in addressing diabetes-related behaviours and glycaemic control. The effect on diabetes was greater in culturally tailored and facilitated interventions that encompassed multiple strategies. Six out of the thirteen studies (46 %) incorporated anthropometric data, physical activity and healthy eating as ways to minimise weight gain and diabetes-related outcomes. Of the six interventions that included anthropometric data, only two (33 %) reported improvement in BMI Z-scores, total skinfold thickness or proportion of body fat. Only one in three (33 %) of the studies that included cardiovascular risk factors reported improvement in diastolic blood pressure after adjusting for baseline characteristics. All studies, except four, were of poor quality (small sample size, poor internal consistency of scale, not controlling for baseline characteristics).
CONCLUSIONS: Due to the small number of studies included in the present review, the findings that culturally tailored and facilitated interventions produce better outcomes than generalised interventions, and that intervention content is more important than the duration or venue, require further investigation.