Background: There is evidence to suggest that immigrant populations from low or medium-income countries to high income countries show a significant change in obesogenic behaviors in the host society, and that these changes are associated with acculturation. However, the results of studies vary depending on how acculturation is measured. The objective of this study is to systematically review the evidence on the relationship between acculturation--as measured with a standardized acculturation scale--and overweight/obesity among adult migrants from low/middle countries to high income countries.
Methods: A systematic review of relevant studies was undertaken using six EBSCOhost databases and following the Centre for Reviews and Dissemination's Guidance for Undertaking Reviews in Health Care.
Results: The initial search identified 1135 potentially relevant publications, of which only nine studies met the selection criteria. All of the studies were from the US with migrant populations from eight different countries. Six studies employed bi-directional acculturation scales and three used uni-directional scales. Six studies indicated positive general associations between higher acculturation and body mass index (BMI), and three studies reported that higher acculturation was associated with lower BMI, as mainly among women.
Conclusion: Despite the small number of studies, a number of potential explanatory hypotheses were developed for these emerging patterns. The 'Healthy Migrant Effect' may diminish with greater acculturation as the host culture potentially promotes more unhealthy weight gain than heritage cultures. This appears particularly so for men and a rapid form of nutrition transition represents a likely contributor. The inconsistent results observed for women may be due to the interplay of cultural influences on body image, food choices and physical activity. That is, the Western ideal of a slim female body and higher values placed on physical activity and fitness may counteract the obesogenic food environment for female migrants.