*2.1. Study Design*

Data for the present study, a secondary analysis, were collected during a prospective cohort study that was designed to estimate the occurrence of chronic disease indicators among students enrolled in a Migrant Education Program (MEP) and a comparison group of non-MEP students [36]. Students qualified for MEP if he or she migrated or had at least one parent who migrated within the prior three years to work in agriculture or fishing as a principal means of employment. "Migrated" was defined as moving temporarily to a different school district or administrative area within the United States [36]. All students enrolled in ninth grade and in MEP in two public high schools in Hidalgo County, Texas (located along the Texas-Mexico border) were recruited to participate and an equal number of students in the ninth grade who were not enrolled in MEP were randomly sampled as a comparison group. Enrollment occurred in 2007 and 2008 with participants followed for up to an additional three years (2008–2010). At the baseline and follow-up assessments, participants completed a survey on demographics, health behaviors, and work characteristics. A minimum clinical examination was also completed, which included measured height, weight, and waist circumference, a noninvasive visual screening for acanthosis nigricans (AN) on the neck, and blood pressure. Prior to partaking in the study, both parental and participant written consent was obtained. Data collection took place each year from January to March to accommodate the migration schedule of MEP students. Data collection took place in a private area in each school during approximately one class period. All interviewers were bilingual, certified in ethical standards for research with human subjects, and retrained in study methods each year to promote adherence to data collection protocols throughout the duration of the study. Additional methodological details are provided by Cooper and colleagues (2016) [36].

This study was approved by the Institutional Review Boards at The University of Texas Health Science Center at Houston (HSC-SPH-07-0284) and Texas A&M University (2010–0878). Written informed consent from parents and written child assent was obtained prior to any data collection.
