BMC Public Health 2007, 7:230 http://www.biomedcentral.com/1471-2458/7/230 Background Physical inactivity is currently acknowledged to be a seri- ous public health burden in the industrialized world [1,2]. A large body of evidence shows that regular physical activity reduces the risk of death from several conditions including coronary heart disease, hypertension, obesity and diabetes type II [3-7]. Despite the known beneficial health effects of physical activity, two- thirds of the popu- lation living in Europe does not achieve the minimum recommended amount of physical activity [8]. While the level of inactivity among the general population is high, non-Western migrants living in Western countries have an even greater risk of being physically inactive [9-12]. This applies, amongst others, to the Turkish migrants in West- ern European countries, such as the Netherlands and Swe- den [13-16]. Previous studies have indicated that the level of physical activity among migrant populations converges towards the level in the host population with greater language flu- ency, increasing numbers of stay in the host country or with increasing generational status [17-20]. These factors are considered to be indicators of the level of 'integration' into the host society, which is often referred to as the proc- ess of acculturation [21]. One of the earliest definitions of acculturation is as follows: "Culture change that is initi- ated by the conjunction of two or more autonomous cul- tural systems. Its dynamics can be seen as the selective adaptation of value systems, the process of integration and differentiation (..)" [21]. Parallel to the studies on acculturation, attention has increasingly focused on barriers for physical activity resulting from the social and environmental context, as is often embedded in ecological models [22-24]. It has, for example, been shown that people living in neighbour- hoods with few sidewalks, a high volume of traffic, no aes- thetic attributes or high crime, i.e. a less attractive neighbourhood, are less likely to engage in physical activ- ity than those who live in more attractive and more exer- cise-supportive areas [24-31]. Moreover, having children can function as a time-barrier for physical activity. Child Acculturation Physical activity during leisure time Contextual Barriers FAinguillruest1ration of the studied associations An illustration of the studied associations. care, often in combination with household activities, decrease the opportunities to be physically active, in par- ticular during leisure time [32-34]. Furthermore, engaging in physical activity at work has also been found to have a negative influence on leisure time activity [35]. However, the studies on the association between accultur- ation and physical activity have largely neglected the effect of contextual barriers. This might be seen as an omission in these studies, as most contextual barriers are in general even more prevalent among migrant than among host populations, due in part to the lower socioeconomic sta- tus of most migrant populations [11,36]. Therefore, the objective of our study was to gain insight into how the association between physical activity during leisure time and acculturation, measured by cultural and social integration, might be modified by the following contextual barriers: having children, occupational physi- cal activity or living in a less attractive environment. Fig- ure 1 illustrates the associations we studied. We analysed this among the Turkish population in the Netherlands, one of the largest ethnic minorities in several other West- ern European countries as well [37,38]. Methods Cross-sectional data were obtained from the LASER study (Lifestyle in Amsterdam: Study among Ethnic gRoups) on prevalence and determinants of health-related behaviour among two non-Western migrant populations in the Netherlands, including the Turkish migrants. Data collec- tion took place from April 2003 until December 2004. This study has been approved by the Medical Ethical Commission of the Academic Medical Centre in Amster- dam, the Netherlands. A random sample was drawn from the Amsterdam popu- lation registry which included people born in Turkey or people who were born in the Netherlands, but have one of both parents being born in Turkey. This implies that the term 'migrants' as used in this study, includes individuals of the first as well as of the second generation. Participants received a letter of invitation, including a translated ver- sion in Turkish. Interviewers of Turkish origin and of the same sex as the participant, visited the participants' homes and requested their cooperation for an interview. A writ- ten informed consent was obtained from each participant in the study. A structured questionnaire was used that included ques- tions about health-related behaviour and determinants, among which socio-economic position, migration history and acculturation. Prior to the study, the questionnaire had been forward and back-translated by professional Turkish translators. Translations were discussed with the Page 2 of 9 (page number not for citation purposes)