Residential mobility and the risk of childhood leukemia

Abstract

Our results do not indicate that higher residential mobility or moving to municipalities with more inhabitants is associated with risk of childhood leukemia.

The Krümmel (Germany) Childhood Leukaemia Cluster: a review and update

“…From 1975 to 2015, the population growth happened almost in parallel in both communities and was almost of the same size in absolute numbers (percentage given in brackets): 5285 (21%) and 5496 (80%), in Geesthacht and Elbmarsch, respectively. A recent cohort study from Switzerland showed that population mixing may have an influence on the risk of childhood leukaemia A c c e p t e d M a n u s c r i p t 17 (Lupatsch et al, 2016), while a case-control study from Finland didn't find any evidence that childhood leukaemia risk is related to population mobility (Jarvela et al, 2016), although there was a suggestive result of a reduced risk with residential mobility at ages 1-2 years. In his reply to Jarvela et al (2016) Kinlen pointed out that the population mixing conditions in Finland do not allow to test Kinlen's hypothesis, because there is no marked influx into a remote rural area (Kinlen 2016), which also applies to the Krümmel cluster.…”

Childhood leukemia and population mixing

“…Unless these population mixing conditions exist, it is unlikely that an effect will be found. As the authors acknowledge ''in Finland overall, there has not been any major population influx or increased residential mobility during the study period'' [1], so their study hardly warrants a conclusion about the validity of the rural population mixing hypothesis. In contrast, supporting evidence from studies of unusual population mixing in rural areas under various circumstances is now extensive [3].…”

“…The authors [1] stated that the latter hypothesis was supported by the large UK study by Law et al [4], but overlooked the subsequently revised analysis by Roman et al [5] which found results directly contrary to those predicted by the Greaves hypothesis.…”

“…Järvelä et al [1] found little evidence during 1990-2011 of an effect of individual residential mobility on childhood leukemia risk in Finland, and concluded that their findings ''do not support the population mixing hypothesis.'' This hypothesis [2] postulates that childhood leukemia is a rare response to an as yet unidentified common (probably subclinical) infection, and that a marked influx into a remote rural area, by promoting contacts between susceptible and infected individuals, would be conducive to a ''mini-epidemic'' of the underlying infection and a consequent excess of cases of the rare response.…”

“…In their Introduction, Järvelä et al [1] referred to certain similarities between the population mixing hypothesis and the delayed infection hypothesis of Greaves, which holds that reduced exposure to general infections during infancy increases childhood leukemia risk. The authors [1] stated that the latter hypothesis was supported by the large UK study by Law et al [4], but overlooked the subsequently revised analysis by Roman et al [5] which found results directly contrary to those predicted by the Greaves hypothesis.…”