Risk of selected childhood cancers and parental employment in painting and printing industries: A register-based case‒control study in Denmark 1968-2015

Multifaceted paternal exposures before conception and their epigenetic impact on offspring

As scientific research progresses, there is an increasing understanding of the importance of paternal epigenetics in influencing the health and developmental path of offspring. Prior to conception, the environmental exposures and lifestyle choices of fathers can significantly influence the epigenetic state of sperm, including DNA methylation and histone changes, among other factors. These alterations in epigenetic patterns have the potential for transgenerational transmission potential and may exert profound effects on the biological characteristics of descendants. Paternal epigenetic changes not only affect the regulation of gene expression patterns in offspring but also increase the risk to certain diseases. It is crucial to comprehend the conditions that fathers are exposed to before conception and the potential outcomes of these conditions. This understanding is essential for assessing personal reproductive decisions and anticipating health risks for future generations. This review article systematically summarizes and analyzes current research findings regarding how paternal pre-pregnancy exposures influence offspring as well as elucidates underlying mechanisms, aiming to provide a comprehensive perspective for an enhanced understanding of the impact that paternal factors have on offspring health.

Five decades of occupational cancer epidemiology

OBJECTIVE

In this discussion paper, we provide a narrative review of past and present occupational cancer studies in the journal with a viewpoint towards future occupational cancer research.

METHOD

We reviewed all references in the journal that mentioned cancer according to relevance to etiology, cancer type, agent type, study design, and study population.

RESULTS

The Scandinavian Journal of Work, Environment & Health has published over 300 manuscripts on occupational cancer over the 50 past years. Although studies of cancer represent the primary health outcome in the journal overall, the relative ranking of cancer manuscripts has declined somewhat over time. A large body of evidence from studies of occupation and industry was apparent both in early research and continuing in recent years. There are several examples of the utility of pooled multi-country collaborative studies. Studies also took advantage of available high-quality national population and cancer registers in Nordic countries. There have been notable shifts in focus with regard to the cancer types examined, with increases in publications examining female breast cancer over the decades. The interplay of studies of occupational and environmental cancer has also been apparent.

CONCLUSIONS

The journal offers a unique viewpoint to consider the evolution of occupational cancer evidence over time. Studies of occupational cancer have played a central role in global cancer hazard identification efforts. Although much has been gained, there remains a need for renewed global support for occupational cancer research. Concerted efforts will be needed to ensure a future robust evidence-base for occupational and environmental cancer worldwide.

Correlation of BARD1 gene polymorphisms with risk of neuroblastoma: a meta-analysis

BRCA1-associated RING domain protein 1 (BARD1) gene polymorphisms may be associated with neuroblastoma (NB) susceptibility. However, the results remain controversial. Relevant studies were identified by searching PubMed, Web of Science, Embase, China National Knowledge Infrastructure databases up to March 5, 2023. The strength of the association between BARD1 polymorphisms and susceptibility of NB was assessed by calculating odds ratios (ORs) and 95% confidence intervals (95% CIs) through the fixed- or random-effects model. Eight articles involving 12 studies were finally included. We found that rs6435862 T > G, rs3768716 A > G, rs17487792 C > T and rs7587476 C > T variant increase the risk of NB in allelic, dominant, recessive, homozygous and heterozygous genetic models, while rs7585356 G > A variant appeared protective against NB. When stratified by ethnicity, subgroup analysis indicated that the above association remained significant in Caucasian populations in all genetic models, except for rs7585356G > A polymorphism in Asians. In Asian populations, we found the similar results in the allelic and dominant model of rs6435862 T > G, rs3768716 A > G, rs17487792 C > T and rs7587476 C > T as in Caucasians, while there lacked a significant association in the other three model. In addition, rs7585356 G > A was not associated with an increased risk of NB in the Asian population. After Bonferroni correction, significant associations for rs7585356 G > A disappeared in both Asian and Caucasian populations, with no significant association found for rs7587476 in the allelic and dominant models among Asians. BARD1 polymorphisms might be significantly associated with NB susceptibility. It is crucial that these finding should be further confirmed through extensive and well-planned studies.

Risk factors for childhood brain tumours: A systematic review and meta-analysis of observational studies from 1976 to 2022

BACKGROUND

Childhood brain tumours (CBTs) are the leading cause of cancer death in children under the age of 20 years globally. Though the aetiology of CBT remains poorly understood, it is thought to be multifactorial. We aimed to synthesize potential risk factors for CBT to inform primary prevention.

METHODS

We conducted a systematic review and meta-analysis of epidemiological studies indexed in the PubMed, Web of Science, and Embase databases from the start of those resources through 27 July 2023. We included data from case-control or cohort studies that reported effect estimates for each risk factor around the time of conception, during pregnancy and/or during post-natal period. Random effects meta-analysis was used to estimate summary effect sizes (ES) and 95% confidence intervals (CIs). We also quantified heterogeneity (I2) across studies.

FINDINGS

A total of 4040 studies were identified, of which 181 studies (85 case-control and 96 cohort studies) met our criteria for inclusion. Of all eligible studies, 50% (n = 91) were conducted in Europe, 32% (n = 57) in North America, 9% (n = 16) in Australia, 8% (n = 15) in Asia, 1% (n = 2) in South America, and none in Africa. We found associations for some modifiable risk factors including childhood domestic exposures to insecticides (ES 1.44, 95% CI 1.20-1.73) and herbicides (ES 2.38, 95% CI 1.31-4.33). Maternal domestic exposure to insecticides (ES 1.45, 95% CI 1.09-1.94), maternal consumption of cured meat (ES 1.51, 95% CI 1.05-2.17) and coffee ≥ 2 cups/day (ES 1.45, 95% 95% CI 1.07-1.95) during pregnancy, and maternal exposure to benzene (ES 2.22; 95% CI 1.01-4.88) before conception were associated with CBTs in case-control studies. Also, paternal occupational exposure to pesticides (ES 1.48, 95% CI 1.23-1.77) and benzene (ES 1.74, 95% CI 1.10-2.76) before conception and during pregnancy were associated in case-control studies and in combined analysis. On the other hand, assisted reproductive technology (ART) (ES 1.32, 95% CI 1.05-1.67), caesarean section (CS) (ES 1.12, 95% CI 1.01-1.25), paternal occupational exposure to paint before conception (ES 1.56, 95% CI 1.02-2.40) and maternal smoking > 10 cigarettes per day during pregnancy (ES 1.18, 95% CI 1.00-1.40) were associated with CBT in cohort studies. Maternal intake of vitamins and folic acid during pregnancy was inversely associated in cohort studies. Hormonal/infertility treatment, breastfeeding, child day-care attendance, maternal exposure to electric heated waterbed, tea and alcohol consumption during pregnancy were among those not associated with CBT in both case-control and cohort studies.

CONCLUSION

Our results should be interpreted with caution, especially as most associations between risk factors and CBT were discordant between cohort and case-control studies. At present, it is premature for any CBT to define specific primary prevention guidelines.

Part 2: The Pediatric Hazards of Art Materials

Children can encounter art materials that contain hazardous substances at school, in the home, and during outside activities. Hazardous substances can be found in both art materials that are made to be used by children and art materials used by adults. Some of these materials can be severe irritants, allergens, carcinogens, or other chronic disease hazards. Many of the most frequently used and potentially most hazardous materials are found in the categories of solvents, pigments, and adhesives. Selected members of these categories and where they may be found in common art materials are briefly discussed. Preventive techniques that specifically address the potential hazards of each category are included. [Pediatr Ann. 2023;52(6):e219-e230.].

Risk of Cancer in Children of Parents Occupationally Exposed to Hydrocarbon Solvents and Engine Exhaust Fumes: A Register-Based Nested Case-Control Study from Sweden (1960-2015)

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 <20y 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 (OR=1.64; 95% CI: 1.05, 2.58), aliphatic/alicyclic HCS with germ cell tumors (OR=1.52; 95% CI: 0.89, 2.59), and gasoline/diesel EEF with astrocytoma (OR=1.40; 95% CI: 1.04, 1.88), myeloid leukemia (OR=1.53; 95% CI: 0.84, 2.81), lymphomas (OR=1.60; 95% CI: 0.85, 3.02 for Hodgkin; OR=1.44; 95% CI: 0.71, 2.91 for non-Hodgkin), and epithelial tumors (OR=1.51; 95% CI: 0.93, 2.44). Paternal exposure to gasoline EEF was associated with Hodgkin lymphoma (OR=1.21; 95% CI: 1.01, 1.44) and soft tissue sarcomas (OR=1.22; 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.

Exposure to PM2.5 constituents and risk of adult leukemia in Denmark: A population-based case-control study

BACKGROUND

Leukemia is one of the most common forms of hematologic malignancy, which can affect people of all ages. We previously showed an association between exposure to ambient particulate matter 2.5 μg (PM_2.5) and risk for leukemia in adults. The aim of this study was to investigate which PM_2.5 constituents were responsible for our previous observation.

METHODS

This is a nationwide register-based case-control study. We identified 14,983 persons diagnosed with leukemia at age 20 or above, 1989-2014, in the Danish Cancer Registry. We selected up to four sex and age-matched controls per case at random from the entire Danish population (n = 51,613). We modelled concentrations of ambient PM_2.5 and its constituents at the addresses of cases and controls for the 10-year period before index date with a state-of-the-art multiscale air pollution modeling system. We used conditional logistic regression to estimate odds ratios (ORs) adjusted for individual and neighborhood level socio-demographic variables.

RESULT

The results showed higher risk for overall leukemia in association with interquartile range exposure to PM_2.5 (OR = 1.09; 95% CI: 1.02, 1.17), black carbon (BC) (OR = 1.02; 95% CI: 1.00, 1.03), secondary inorganic aerosols (SIA) (OR = 1.15; 95% CI: 1.03, 1.29) and its components ammonium (NH₄) (OR = 1.08; 95% CI: 1.00, 1.17) and nitrate (NO₃) (OR = 1.08; 95% CI: 1.02, 1.14). In leukemia subtype analysis, statistically significant associations were found for AML with PM_2.5 (OR = 1.14; 95% CI: 1.00, 1.29), BC (OR = 1.03; 95% CI: 1.00, 1.07), SIA (OR = 1.23; 95% CI: 1.01, 1.51), NH₄ (OR = 1.16; 95% CI: 1.01, 1.34) and NO₃ (OR = 1.12; 95% CI: 1.01, 1.24). The association between PM_2.5 and leukemia persisted in two pollutants models including sum of primary emitted black and organic carbon (BC + OC), secondary organic aerosols (SOA), or sea-salt. The association between black carbon (BC) and leukemia persisted in two pollutants models including organic carbon (OC). The three pollutant model with sulfate (SO₄), NH₄ and NO₃ showed an association with NO₃ but not with SO₄ or NH₄.

CONCLUSION

Ambient concentrations of the PM_2.5 components BC, NH₄ and NO₃ at the residence showed associations with risk of incident leukemia in adults.