Paternal occupational contact level and childhood leukaemia in rural Scotland: a case-control study

In a national Scottish study of 809 cases of leukaemia and non-Hodgkins lymphoma diagnosed in 1950–89 among children aged 0–4 years who were born in Scotland, together with 2363 matched population controls, we investigated one aspect of the infective hypothesis. This concerns whether in rural areas (where the prevalence of susceptible individuals is likely to be higher) the risk is greater among the young children of men whose work involves contacts with many different people, particularly children, as noted in certain childhood infections. A positive trend was found in rural areas across 3 levels of increasing paternal occupational contact (as recorded at birth) by each of 2 previously defined classifications; no such effect was found in urban areas. The rural trend was more marked in that part of the study period with greater population mixing, but the difference from the period with less mixing was not itself significant, leaving open whether these rural findings reflect the extreme isolation of much of rural Scotland, or the effects in such areas of a degree of population mixing. In marked contrast, among the 850 cases and 2492 controls aged 5–14, those in rural areas in the higher population mixing period showed a significantly decreasing trend with increasing paternal occupational contact level. This would be consistent with immunity produced either by earlier infection at ages 0–4 years, or directly by low doses of the infective agent that were largely immunizing at these older ages. The findings overall provide further support for infection underlying childhood leukaemia and for the role of adults.© 2001 Cancer Research Campaign http://www.bjcancer.co

Childhood leukaemia and population movements in France, 1990–2003

In a national study, we investigated the incidence of childhood leukaemia (CL) over a 14-year period in France in relation to several measures based on the proportion of individuals who changed address between the last two national censuses. A positive association was found with the proportion of migrants who came from a distant place. The further the migrants came, the higher was the incidence of leukaemia, particularly among children aged 0–4 years in ‘isolated' communes at the time of diagnosis (RR=1.4, 95% CI: 1.1,1.8 in the highest category of migration distance). Although the role of the population density was less obvious, a more marked association was found above a certain threshold. No association with the proportion of commuters was observed

Factors associated with childhood cancer in a national cohort study.

Information on 16,193 infants delivered in Great Britain in one week of April, 1970 was collected by midwives at the birth and during the first 7 days of life. Using multiple sources, 33 children developing cancer by 1980 were identified from this cohort, giving an incidence of 2.04 per 1,000 total births by the age of 10. Comparisons of these 33 children were made with 99 controls, three for each index case, matched on maternal age, parity and social class. Statistically significant associations were initially found with maternal X-rays and smoking during pregnancy, and the use of analgesics such as pethidine during labour, confirming the findings of retrospective case-control studies. Unexpected statistically significant associations were found with delivery of the child outside term, and drug administration in the first week of life. The latter was found in the absence of an association with neonatal abnormalities in the child and relates mostly to the administration of prophylactic drugs such as vitamin K. Logistic regression involving the whole cohort showed independent statistical associations with maternal smoking (OR 2.5), and drugs to the infant (OR 2.6). After adjusting for these factors no other statistically significant associations were found

Cancer of the testis and month of birth.

It has recently been reported that a series of testis cancers shows a temporal cycle in birth dates with a peak in certain months. This observation has been tested by an examination of a larger series covering all testis cancers diagnosed in the years 1971-84 in England and Wales, in men born in 1940 or later. Limited evidence was found of a 4-monthly cycle, but this was due to a 2-monthly cycle shown by teratomas in men born in the years 1945-49. No evidence was found for such a cycle outside this period, nor for a peak in any particular month

A proportionate study of cancer mortality among members of a vegetarian society.

A proportionate study was carried out of the causes of death of the 759 Vegetarian Society members whose deaths were recorded in Society records and whose death certificates could be traced. Compared to the general population, a lower proportion of deaths from respiratory diseases and from lung cancer was noted particularly in long-standing members, consistent with the evidence that vegetarians smoke less than the average. The proportion of deaths from colorectal cancer was slightly lower than in the general population but there was no reduction in the proportions of deaths from other diseases that have been linked with meat or fat consumption, such as cardiovascular diseases and breast cancer. The proportions of deaths from stomach cancer and from accidents and violence were greater than expected. The significance of the findings is discussed and also the possible limitations of the proportionate method of analysis in relation to studies of vegetarians