Abstract
BACKGROUND: Immigration to the United States has been associated with obesity, yet the relationship of acculturation to obesity and energy balance (ie, physical activity/dietary intake) in adults is a complex issue. Limited longitudinal data are available on immigrant Asians and Pacific Islanders. DESIGN: Analyses were conducted on baseline data and change data from baseline to 24 months in the hotel-based cluster-randomized Work, Weight and Wellness trial involving 15 control and 15 intervention hotels on the island of Oahu, Hawaii. SAMPLE: Participants were adult employees of predominantly Asian and Pacific Islander ancestry who were assessed one or more times over the course of 24 months. The full sample consisted of 4,236 hotel workers (about 40% of hotel workforce) at baseline, 3,502 hotel workers at Year 1 and 2,963 hotel workers at the 24-month follow up. One thousand one hundred fifteen hotel workers had at least two measurements, and were included in the analysis. INTERVENTION: The Work, Weight, and Wellness trial was designed to promote weight loss via motivation and support for increases in physical activity and increased access to and consumption of healthy low-fat/low-energy foods. The measure of acculturation consisted of a score that was a compilation of a participant's age when he or she immigrated to the United States, country of birth, language spoken at home, and years of education. STATISTICAL ANALYSES: We used mixed effect regression models for cross-sectional baseline models and longitudinal multilevel regression analysis of change in diet and physical activity behaviors and obesity over time using a random intercept. Estimates of the intervention effect are expressed as an annual rate of change for all study outcomes. RESULTS: At baseline acculturation was positively associated with body mass index; physical activity level; and fruit, meat, and sweetened drink intake level. In analyses of change across 24 months, acculturation did not significantly influence change in dietary intake or indexes of obesity (ie, body mass index or waist-to-height ratio). However physical activity increased significantly more in the intervention group during the course of the intervention compared with the control group, which decreased activity, when sociodemographic factors (including acculturation) and food intake behavior were controlled for.