摘要:Objectives. We examined whether the interactions between primarily speaking English at home and community-level measures (median household income and immigrant composition) are associated with physical inactivity and obesity. Methods. We pooled the 2005 and 2007 Los Angeles County Health Survey data to construct a multilevel data set, with community-level median household income and immigrant density as predictors at the community level. After controlling for individual-level demographic variables, we included the respondent’s perceived community safety as a covariate to test the hypothesis that perceived public safety mediates the association between acculturation and health outcomes. Results. The interaction between community median household income and primarily speaking English at home was associated with lower likelihoods of physical inactivity (odds ratio [OR] = 0.644; 95% confidence interval [CI] = 0.502, 0.825) and obesity (OR = 0.674; 95% CI = 0.514, 0.882). These odds remained significant after we controlled for perceived community safety. Conclusions. Resources in higher-income areas may be beneficial only to residents fully integrated into the community. Future research could focus on understanding how linguistic isolation affects community-level social learning and access to resources and whether this differs by family-level acculturation. Immigrants face the challenge of assimilating into their host country while maintaining values, beliefs, and behaviors from their homelands. Both acculturation and ethnic identity can influence health, and the construct of acculturation has been included in more and more health studies. 1,2 Despite long-standing sociocultural theories of behavior that suggest that one’s behavior is the result of a dynamic interplay between internal, individual-level factors and social-cultural context, 3–6 few public health studies have explored this interaction. 7 A critical review noted that studies of acculturation tend to separate culture from the larger social structure and the dynamic social processes in which behavior and beliefs are generated, and to relegate consideration of the socio-economic challenges associated with immigration, poor English language skills, and poverty, to their effects as separate or confounding variables. 8 (p981) For an immigrant, the interaction between acculturation status and the larger social structure in the host society could be important for health, as an inadequate level of acculturation in some contexts might result in reduced access to resources. In particular, undocumented immigrants have no federal coverage of health care under the Affordable Care Act. Therefore, access to resources may differ by legal status. However, in some settings, ethnic identity may buffer and even be protective against public health challenges in the United States (e.g., immigrants may maintain their dietary customs, which often include more whole foods, despite the excessive availability of processed foods in the United States). 9 From a methodological perspective, multilevel models can provide a better understanding of this kind of interaction, whereby community-level factors, individual-level acculturation, and the cross-level interaction effects between the two can all be included as regressors of the outcome variable. However, very few public health studies have considered the cross-level interaction between acculturation and community-level factors on health behaviors and health outcomes. In an attempt to fill this research gap, we used population-based survey data to explore the cross-level interaction between community-level factors (median household income and immigrant composition) and individual-level linguistic acculturation (language preference at home). This study includes 2 independent variables that have been infrequently considered in previous studies of immigrant health: community immigrant composition and perceived community safety. Among various community-level factors that could influence residents’ health outcomes, community immigrant composition has begun to receive academic attention. 10 Aside from individual-level acculturation indicators such as language preference and place of birth, living in a community with a high proportion of immigrants may be an independent predictor of one’s level of acculturation since people who are less acculturated may choose to live in ethnic enclaves. 11 Perceived community safety has been shown to be a strong predictor of individual-level health outcomes such as having a mental health disorder or being overweight. 12–15 The causal pathways between an unsafe community and negative health outcomes such as obesity could operate through reduced physical activity 16–20 or through stress, which can disrupt energy metabolism and food intake regulation. 21–24 Because acculturation has been shown to be associated with one’s perception of community safety 25 and predicts many different health behaviors and health outcomes, 1,2 it is likely that an individual’s level of acculturation could modify the impact of community-level factors on health outcomes. Because understanding of these causal mechanisms is still far from conclusive, a study of the interaction between individuals’ level of acculturation and community-level factors could help reveal the complex pattern of acculturation and health. From the perspective of public health interventions, a good understanding of acculturation, perceived safety, and health could inform intersectoral collaboration between public safety, K-12 (kindergarten through 12th grade) and adult education, immigrant services, and public health agencies.