Background Birth defects have been consistently associated with elevated childhood cancer risks; however, the relationship between congenital heart disease (CHD) and childhood cancer remains conflicting. Considering the increasing patient population with CHD after improvements in their life expectancies, insights into this relationship are particularly compelling. Thus, we aimed to determine the relationship between CHD and cancer in Swedish children. Methods and findings All individuals registered in the Swedish Medical Birth Register (MBR) between 1973 and 2014 were included in this population–based cohort study (n = 4,178,722). Individuals with CHD (n = 66,892) were identified from the MBR and National Patient Register, whereas cancer diagnoses were retrieved from the Swedish Cancer Register. The relationship between CHD and childhood cancer (<20 years at diagnosis) was evaluated using Cox proportional hazards regression models. We observed increased risks of cancer overall, leukemia, lymphoma, and hepatoblastoma in children with CHD, but after adjustment for Down syndrome, only the increased lymphoma (hazard ratio (HR) = 1.64, 95% confidence interval (CI) 1.11 to 2.44) and hepatoblastoma (HR = 3.94, 95% CI 1.83 to 8.47) risk remained. However, when restricting to CHD diagnoses from the MBR only, i.e., those diagnosed around birth, the risk for childhood cancer overall (HR = 1.45, 95% CI 1.23 to 1.71) and leukemia (HR = 1.41, 95% CI 1.08 to 1.84) was more pronounced, even after controlling for Down syndrome. Finally, a substantially elevated lymphoma risk (HR = 8.13, 95% CI 4.06 to 16.30) was observed in children with complex CHD. Limitations of the study include the National Patient Register not being nationwide until 1987, in addition to the rareness of the conditions under study providing limited power for analyses on the rarer cancer subtypes. Conclusions We found associations between CHD and childhood lymphomas and hepatoblastomas not explained by a diagnosis of Down syndrome. Stronger associations were observed in complex CHD.

Background Some largely inconsistent associations between parental occupational dust exposure and childhood cancer have been reported, with maternal exposures inadequately studied. The authors examined whether maternal or paternal occupational exposure to animal, wood, textile, or paper dust around a child's birth was associated with an increased risk of childhood cancer, both overall and by type (leukemias, lymphomas, central nervous system tumors, and other cancers). Methods In this nationwide, register‐based, case‐control study, children who were diagnosed with cancer from 1960 to 2015 were compared with up to 25 matched controls regarding maternal and paternal occupational dust exposure (9653 cases in maternal analyses and 12,521 cases in paternal analyses). Exposures were assessed using a job‐exposure matrix and occupational information from census and register data. By using conditional logistic regression models, adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated. Results Neither maternal nor paternal occupational exposure to animal, wood, textile, or paper dust was associated with childhood cancer overall, leukemias, or central nervous system tumors. Maternal, but not paternal, wood dust exposure was associated with an increased risk of lymphoma (OR, 1.42; 95% CI, 1.10‐1.84), particularly non‐Hodgkin lymphoma (OR, 2.03; 95% CI, 1.21‐3.40). Conclusions The current study did not confirm the associations reported previously but is the first to suggest a link between maternal occupational exposure to wood dust around pregnancy and lymphoma in the offspring.

Objective To evaluate whether children with neurofibromatosis type 1 (NF1) and tuberous sclerosis have different birth characteristics compared with the general population. Study designWe identified all individuals born in Sweden between 1973 and 2014 from the nationwide Medical Birth Register for whom information on both biological parents was available (n = 4 242 122). Individuals with NF1 and individuals with tuberous sclerosis were identified using data from Swedish population-based health data registers. Using logistic regression models, we assessed the associations between these 2 neurocutaneous syndromes and birth characteristics in a cohort that included 1804 subjects with NF1 and 450 with tuberous sclerosis. ResultsChildren with NF1 and tuberous sclerosis were significantly more likely to be born preterm and via cesarean delivery. In addition, children with NF1 were also more likely to be born with other birth characteristics, such as short length, a large head circumference, and a low Apgar score. Moreover, children with NF1 had an increased odds of being born with a high birth weight or large for gestational age (OR, 1.61; 95% CI, 1.42-1.82 and OR, 1.82; 95% CI, 1.60-2.06, respectively). ConclusionChildren with NF1 and tuberous sclerosis differ from the general population in terms of several birth characteristics, with the strongest associations observed for high birth weight and large for gestational age in individuals with NF1.

Background: It remains unclear whether parental occupational exposure to hydrocarbon solvents (HCS) or engine exhaust fumes (EEF) is associated with higher risks of cancer in the offspring. Objectives: Our aim was to estimate relative risks of childhood cancers associated with maternal or paternal exposure to aliphatic/alicyclic, aromatic, or chlorinated HCS or gasoline/diesel EEF. Methods: We conducted a case–control study in which individuals old, born 1960–2014, were identified from the Swedish National Cancer Register (1960–2015) at first cancer diagnosis and matched to population controls (1 case:25 controls) on birth year and sex. Maternal and paternal occupation around the child’s birth was retrieved for 9,653 cases and 172,194 controls and 12,521 cases and 274,434 controls, respectively, using information from six censuses and a nationwide register. Using the Swedish job-exposure matrix (SWEJEM), we assessed exposure to HCS and EEF (any or higher/lower). Odds ratios (ORs) and 95% confidence intervals (CIs) of 15 childhood cancer subtypes were estimated using conditional logistic regression models adjusted for several confounders. Results: Maternal exposure to aromatic HCS was associated with non-Hodgkin lymphoma ( ; 95% CI: 1.05, 2.58), aliphatic/alicyclic HCS with germ cell tumors ( ; 95% CI: 0.89, 2.59), and gasoline/diesel EEF with astrocytoma ( ; 95% CI: 1.04, 1.88), myeloid leukemia ( ; 95% CI: 0.84, 2.81), lymphomas ( ; 95% CI: 0.85, 3.02 for Hodgkin; ; 95% CI: 0.71, 2.91 for non-Hodgkin), and epithelial tumors ( ; 95% CI: 0.93, 2.44). Paternal exposure to gasoline EEF was associated with Hodgkin lymphoma ( ; 95% CI: 1.01, 1.44) and soft tissue sarcomas ( ; 95% CI: 1.00, 1.48). No notable difference was observed between higher and lower exposure. Discussion: Our findings suggest that occupational exposure to HCS or EEF, especially in the mother, may increase the risk of some childhood cancers. They add to the growing literature on adverse effects from HCS and EEF in the child, but replication of these associations in other populations is warranted. https://doi.org/10.1289/EHP11035

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