Urban-rural variations in health in The Netherlands: does selective migration play a part?
Areas that attract many migrants from and lose few migrants to other degrees of urbanicity will in the long run obtain healthier populations, because of demographic and socioeconomic characteristics. However, if these characteristics are accounted for, the opposite is true, with the exception of younger age groups. In extreme cases this may cause spurious findings in cross sectional research into the relation between urbanicity and health. Absolute numbers of migrants need to be very high, however, to make this noticeable at the aggregate level.
Factors in the social environment could trigger the induction of diabetes-related autoantibodies in 1-year-old children. These results point out that our present knowledge of factors influencing the autoimmune process might be widen to also include factors in the social environment of the community.