Comparison of physical activity as an obesity-related behavior between immigrants and native-born US adults

Obesity is a significant public health concern in the US and globally, contributing to substantial medical costs and increased risks of chronic diseases. Physical activity is a key determinant of obesity, and this study addresses the limited data comparing physical activity levels between US immigrants and native-born adults. While previous research has indicated lower obesity rates among immigrants, particularly in the early years after immigration (the "immigrant paradox"), less is known about differences in obesity-related behaviors, especially physical activity. This study aims to fill this gap by comparing physical activity behaviors and their association with obesity between these two groups, providing valuable insights for targeted health interventions.

Existing literature demonstrates a correlation between obesity and increased morbidity and mortality, resulting in substantial economic burdens. Several studies have investigated the etiology of obesity, categorizing contributing factors into genetic, environmental, and behavioral components. Behavioral factors, such as dietary habits and physical activity, are crucial proximal determinants of obesity. While research has shown that US immigrants, despite often having lower socioeconomic status, exhibit lower obesity rates than native-born Americans, especially in the early years of immigration, data comparing obesity-related behaviors, particularly physical activity, remains scarce. Some studies have found that immigrants are less likely to discuss their dietary and physical activity routines with healthcare providers. The "immigrant paradox" has been attributed to factors like a 'healthy immigrant effect', strong social networks, and potential reporting biases. However, obesity risks in immigrants tend to increase with longer durations of residence in the US, converging toward the rates seen in native-born populations. Existing studies highlight the importance of understanding and addressing obesity-related behavior differences between immigrant and native-born populations to develop effective prevention and intervention strategies.

This study utilized data from the 2013 Health Information National Trends Survey (HINTS) cycle 3, a nationally representative sample of US adults aged 18 and older. Data collection was conducted via mail. The independent variable was nativity status (immigrant vs. native-born). Dependent variables included indicators of physical activity (time spent on sedentary activities like watching TV, playing computer games, or web surfing; participation in moderate-intensity exercise; and participation in muscle-strengthening exercises) and BMI. Covariates included gender, age, education level, race/ethnicity, income, disability, and marital status. Univariate analyses (Wald Chi-Square tests for categorical variables, t-tests for continuous variables) described the distribution of demographic characteristics by nativity status. Bivariate analyses explored physical activity behavior and BMI distribution. Multivariate logistic regression models determined adjusted odds ratios (AOR) and 95% confidence intervals (95% CI) for associations between nativity status and physical activity indicators, adjusting for covariates. All analyses were performed using SAS 9.3. The study received IRB exemption under Georgia State University protocols.

A total of 3131 participants were included in the analysis (83% native-born, 17% immigrants). Immigrants were predominantly Hispanic (55.3%), while native-born participants were mostly Non-Hispanic White (67.3%). Immigrants had a slightly lower mean age (51 years) than native-born participants (55 years). Regarding obesity, 25.65% of immigrants were obese compared to 34.4% of native-born individuals. Multivariate logistic regression analysis revealed that, after adjusting for covariates, immigrants were less likely to spend 6 or more hours daily on sedentary leisure activities (Adjusted OR = 0.64; 95% CI: 0.42-0.97; p= 0.0350). Furthermore, immigrants were more likely to engage in moderate-intensity physical activity at least once a week (Adjusted OR = 1.48; 95% CI: 1.07-2.05; p = 0.0192). The association between immigrant status and muscle strength training was not statistically significant (Adjusted OR = 1.28; 95% CI: 0.98-1.67; p = 0.0757). Additional analyses controlling for disability showed that the associations between immigrant status and both moderate-intensity exercise and muscle strength training remained largely consistent, although the latter was not statistically significant after controlling for disability.

This study provides novel evidence on the differences in physical activity behaviors between US immigrants and native-born adults. The findings suggest that immigrants, particularly Hispanic immigrants, exhibit healthier lifestyle choices related to physical activity, which may contribute to the lower prevalence of obesity observed in previous research. The higher likelihood of moderate-intensity exercise among immigrants and their reduced engagement in prolonged sedentary behavior align with previous studies showing less screen exposure among non-US-born parents in low-income, minority families. However, a significant portion of both immigrant and native-born participants did not meet recommended physical activity guidelines, highlighting the need for public health initiatives to promote physical activity in all segments of the population. The observed positive association between higher physical activity and lower obesity prevalence among immigrants could inform the development of targeted interventions to promote healthy lifestyles and reduce obesity rates in the US. Interventions should consider the cultural contexts and specific needs of immigrant populations.

This study demonstrates a positive association between immigrant status and higher levels of physical activity, potentially contributing to lower obesity prevalence. Future prospective studies with larger, more diverse samples, longer follow-up periods, and the inclusion of subsequent generations are needed to examine the long-term effects of acculturation and other factors on obesity-related behaviors and health outcomes. Such studies should help refine targeted interventions for promoting physical activity and preventing obesity among both immigrant and native-born populations.

This study relies on cross-sectional data, limiting the ability to establish causality and fully account for potential confounders. The small sample size of immigrants with long-term residence in the US limited the analysis of acculturation effects. The retrospective nature of the data and the inability to conduct longitudinal follow-up are further limitations. While missing data were minimal, it's possible that the findings could be slightly altered if this were not the case.