Feasibility of conducting a longitudinal, transnational study of filipino migrants to the United States: a dual-cohort design.

Most studies of immigrant health are cross-sectional and fail to collect information prior to migration, leading to potential bias and confounding. The present pilot study examines the feasibility of studying migrants prospectively, with baseline data collected before migration. The study followed two cohorts of Filipinos for one year, a migrant cohort (n=27) that emigrated to the U.S. and a second non-migrant cohort (n=26) that remained in the Philippines. The one-year retention rate was 96%. The migrant cohort arrived in the U.S. within two months of their baseline assessment. Migrants and non-migrants did not differ with regard to body mass index, waist circumference, or waist to hip ratio at baseline or at follow-up. It is feasible to conduct a transnational, longitudinal study of two cohorts of Filipinos. This design provides important pre-migration information, is analogous to a natural experiment, can be upscaled, and allows for a rigorous examination of immigrant health.