Childhood @entity1778 (CL) may have an infectious cause and population mixing may therefore increase the risk of CL. We aimed to determine whether CL was associated with population mixing in Switzerland. We followed @entity1 aged <16 years in the Swiss National Cohort 1990-2008 and linked CL cases from the Swiss Childhood Cancer Registry to the cohort. We calculated adjusted hazard ratios (HRs) for all CL, CL at age <5 years and @entity981 ( @entity981 ) for three measures of population mixing (population growth, in-migration and diversity of origin), stratified by degree of urbanisation. Measures of population mixing were calculated for all municipalities for the 5-year period preceding the 1990 and 2000 censuses. Analyses were based on 2,128,012 @entity1 of whom 536 developed CL. HRs comparing highest with lowest quintile of population growth were 1.11 [95 % confidence interval (CI) 0.65-1.89] in rural and 0.59 (95 % CI 0.43-0.81) in urban municipalities (interaction: p = 0.271). Results were similar for @entity981 and for CL at age <5 years. For level of in-migration there was evidence of a negative association with @entity981 . HRs comparing highest with lowest quintile were 0.60 (95 % CI 0.41-0.87) in urban and 0.61 (95 % CI 0.30-1.21) in rural settings. There was little evidence of an association with diversity of origin. This nationwide cohort study of the association between CL and population growth, in-migration and diversity of origin provides little support for the population mixing hypothesis.

Population mixing and the risk of childhood XXXX in Switzerland: a census-based cohort study.

@entity1 :: ('9606', 'Species') :: ['children'] @entity1778 :: ('MESH:D007938', 'Disease') :: ['leukaemia'] @entity981 :: ('MESH:D054198', 'Disease') :: ['ALL', 'acute lymphoblastic leukaemia']
@entity1778 :: (MESH:D007938,Disease) :: ['leukaemia']
