Length of residence and obesity among immigrants in Spain.

OBJECTIVE Various studies in the USA and Canada have consistently shown a positive association between length of residence of immigrants and obesity. Studies in European countries have obtained less consistent results. The present work assesses the influence of length of residence on the frequency of obesity in immigrants in the city of Madrid, Spain. DESIGN We studied a sample of 7155 persons aged 18 years and over residing in the city of Madrid, who were was surveyed between November 2004 and May 2005. Information was collected on immigrant status (country of birth), length of residence in Spain, obesity, sociodemographic characteristics and lifestyle. RESULTS Compared with the Spanish population, the odds for obesity in the immigrant population by length of residence was less than one in all groups, becoming closer to one with increasing time of residence (OR = 0.67, 0.73 and 0.81 for immigrants with less than 2, 2-4 and 5-9 years of residence in Spain, respectively), up to 10 or more years of residence, when it declined (OR = 0.69). The magnitude of this association was considerably reduced after adjusting for sociodemographic variables and for perceived health, but was not further modified after adjusting for lifestyle variables. CONCLUSIONS Length of residence of immigrants in the city of Madrid is not associated with the frequency of obesity. It is possible that the circumstances immigrants encounter after arriving in Spain do not involve an overexposure to factors favouring obesity, relative to those they bring with them.