[PELFI Project: Recruitment and Sociodemographic Characteristics of Immigrant and Autochthonous Families from Alicante and Barcelona City Subcohorts].

This study is a part of the multi-centre project "Platform of Longitudinal Studies of Immigrant Families (PELFI)" of the Immigration and Health Subprogram of the CIBER-ESP. It describes the field work and data collection of two sub-cohorts of immigrant and native families, and their main socio-demographic characteristics. Prospective observational cohort study in carried out in Barcelona and Alicante, Spain. The study population is a a non-probabilistic sample of 180 families of Colombian, Ecuadorian and Moroccan origin and 50 families of Spanish origin. We interviewed adults aged 18-65 years and adolescents aged 12-17 years in each family, through two questionnaires (adolescent/adult). The cooperation rate was 82.0% with an average recruitment rate of 1.3 families per day. In total, 250 families have been recruited, 82 from Ecuador, 82 from Colombia, 29 from Morocco and 57 from Spain. A total of 473 adults (59.8% women and 68.5% employed) were surveyed. Immigrant adults have an average of 13 years living in Spain. A total of 304 adolescents (53.9% female, 27.1% born in Spain but with immigrant parents) were surveyed. The combination of non-probabilistic techniques promoted access and improved recruitment speed. This study provides key information for the design and improvement of cohort studies with immigrant families.