Parental smoking and childhood cancer: results from the United Kingdom Childhood Cancer Study

Abstract

There are strong a priori reasons for considering parental smoking behaviour as a risk factor for childhood cancer but case -control studies have found relative risks of mostly only just above one. To investigate this further, self-reported smoking habits in parents of 3838 children with cancer and 7629 control children included in the United Kingdom Childhood Cancer Study (UKCCS) were analysed. Separate analyses were performed for four major groups (leukaemia, lymphoma, central nervous system tumours and other solid tumours) and more detailed diagnostic subgroups by logistic regression. In the four major groups, after adjustment for parental age and deprivation there were nonsignificant trends of increasing risk with number of cigarettes smoked for paternal preconception smoking and nonsignificant trends of decreasing risk for maternal preconception smoking (all P-values for trend 40.05). Among the diagnostic subgroups, a statistically significant increased risk of developing hepatoblastoma was found in children whose mothers smoked preconceptionally (OR ¼ 2.68, P ¼ 0.02) and strongest (relative to neither parent smoking) for both parents smoking (OR ¼ 4.74, P ¼ 0.003). This could be a chance result arising from multiple subgroup analysis. Statistically significant negative trends were found for maternal smoking during pregnancy for all diagnoses together (Po0.001) and for most individual groups, but there was evidence of under-reporting of smoking by case mothers. In conclusion, the UKCCS does not provide significant evidence that parental smoking is a risk factor for any of the major groups of childhood cancers. There are strong a priori reasons for considering parental smoking behaviour as a risk factor for childhood cancer. Many proven carcinogens are present in tobacco and tobacco smoke (Hecht, 1999;Hoffmann and Hoffmann, 1997). Tobacco-related compounds have also been detected in human placenta, fetal blood, urine of offspring and in breast milk of smoking mothers (Perlman and Dannenberg, 1942;Everson et al, 1986Everson et al, , 1988Woodward et al, 1986;Hansen et al, 1992;Myers et al, 1996;Pinorini-Godly and Myers, 1996;Arnould et al, 1997;Daube et al, 1997).Previous case -control studies have tended to show weak associations between maternal cigarette smoking during pregnancy and childhood cancers (IARC, 1986;Severson et al, 1993;Tredaniel et al, 1994;Sorahan et al, 1995Sorahan et al, , 1997a Sorahan et al, , b, 2001Klebanoff et al, 1996;Shu et al, 1996). There is somewhat stronger and more consistent evidence for a paternal preconceptional effect, although relative risks in most case -control studies are only just above one (Severson et al, 1993;Shu et al, 1996;Ji et al, 1997;Sorahan et al, 1997b;. This effect has been attributed to germ-cell mutations during spermatogenesis caused by tobacco products (Wyrobeck, 1993;Wyrobek and Adler, 1996;Woodall and Ames, 1997). Relevant studies are reviewed by Thornton and Lee (1998).The United Kingdom Childhood Cancer Study (UKCCS) is a nationwide population-based...

Risk of childhood germ cell tumors in association with parental smoking and drinking

“…7,[17][18][19] Previous investigations on the association between smoking and a subsequent risk of childhood cancers have generated positive and negative results. 22,23,[33][34][35][36] The negative finding from our study, as well as an earlier study 37 on GCT, might be a result of the finding that the carcinogenic effect of smoking is offset by its antiestrogenic effect. 18,19 Whereas alcohol and its metabolites have been shown to be teratogenic, mutagenic, and carcinogenic, 38 -40 the relation between alcohol consumption and childhood cancers has not always been consistent across studies.…”

“…Although we could not verify whether participation was related to lifestyle factors, we found that the rates of smoking and drinking among control parents were similar to those reported by earlier studies. 8,10,36 To our knowledge the current study represents the most recent available information regarding childhood GCT in the United States and the largest epidemiologic study ever conducted for childhood GCT. Our study has sufficient statistical power (80%) to detect a moderate effect (OR Ͼ 1.6) of parental smoking and drinking on GCT.…”

Perinatal risk factors for hepatoblastoma

“…An excess of maternal pre-eclampsia, without adjustment for VLBW, has been noted (Ansell et al, 2005). Three previous studies have found that maternal smoking significantly raised offspring risk (Pang et al, 2003;Sorahan and Lancashire, 2004;McLaughlin et al, 2006), whereas a fourth did not (Buckley et al, 1989); associations remained after adjustment for VLBW in two studies (Pang et al, 2003;Spector and Ross, 2003;McLaughlin et al, 2006). Lastly, a ninefold increased risk of hepatoblastoma was reported among children born following infertility treatment, which was independent of birth weight (McLaughlin et al, 2006).…”

Second hand smoke, age of exposure and lung cancer risk

“…A worldwide study among students aged [13][14][15] years (58), showed that nearly half of never smokers were exposed to SHS at home (46.8%), and a similar percentage were exposed in places other than the home (47.8%). Never smokers exposed to SHS at home were 1.4-2.1 times more likely to be susceptible to initiating smoking than those not exposed.…”

“…However, less is known about the effect of the age of exposure, particularly to SHS, on the risk of NSCLC (1)(2)(3). Most studies (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) have focused on paternal and maternal smoking during pregnancy and the effect on childhood illnesses and cancers in general or more recently the risk of lung cancer for non-smoking women exposed to tobacco smoke during childhood (19)(20)(21)(22)(23)(24)(25)(26)(27)(28). Very few studies (19,22,29,30) have focused on the effect of the period of exposure relevant for lung cancer development while also assessing the significance of lifetime exposure by location.…”