Association of common maternal infections with birth outcomes: a multinational cohort study.

PURPOSE: It is unclear whether common maternal infections during pregnancy are risk factors for adverse birth outcomes. We assessed the association between self-reported infections during pregnancy with preterm birth and small-for-gestational-age (SGA) in an international cohort consortium. METHODS: Data on 120,507 pregnant women were obtained from six population-based birth cohorts in Australia, Denmark, Israel, Norway, the UK and the USA. Self-reported common infections during pregnancy included influenza-like illness, common cold, any respiratory tract infection, vaginal thrush, vaginal infections, cystitis, urinary tract infection, and the symptoms fever and diarrhoea. Birth outcomes included preterm birth, low birth weight and SGA. Associations between maternal infections and birth outcomes were first assessed using Poisson regression in each cohort and then pooled using random-effect meta-analysis. Risk ratios (RR) and 95% confidence intervals (CI) were calculated, adjusted for potential confounders. RESULTS: Vaginal infections (pooled RR, 1.10; 95% CI, 1.02-1.20) and urinary tract infections (pooled RR, 1.17; 95% CI, 1.09-1.26) during pregnancy were associated with higher risk of preterm birth. Similar associations with low birth weight were also observed for these two infections. Fever during pregnancy was associated with higher risk of SGA (pooled RR, 1.07; 95% CI, 1.02-1.12). No other significant associations were observed between maternal infections/symptoms and birth outcomes. CONCLUSION: Vaginal infections and urinary infections during pregnancy were associated with a small increased risk of preterm birth and low birth weight, whereas fever was associated with SGA. These findings require confirmation in future studies with laboratory-confirmed infection diagnosis.

Navigating the COVID-19 pandemic: Experiences and self-management approaches adopted by people with interstitial lung disease.

BACKGROUND: People with interstitial lung disease (ILD) were deemed more vulnerable to the SARS-CoV-2 virus and isolated as a means of reducing risk of infection. This study examined the impact of the pandemic on daily life, psychological wellbeing and access to healthcare and identified approaches undertaken to remain safe. METHODS: Four specialist clinics in tertiary centres in Australia (Victoria: two sites; New South Wales: one site; Western Australia: one site) recruited patients with ILD during an 8-week period from March 2021. Semi-structured telephone interviews were conducted with transcripts analysed using principles of grounded theory. RESULTS: Ninety participants were interviewed between April and December 2021. Participants were predominantly female, former smokers with an average age of 66 years. IPF and connective tissue-ILD being the most common subtypes. Five main themes were identified: vulnerability reduced social interaction and isolation, access to healthcare services and support, staying active, emotional and psychological impact. Self-management strategies included staying active both physically and mentally. DISCUSSION: Self-management was key to managing the impact of the pandemic. In combination with advances in technology, implementation of strategies for monitoring wellbeing and support for self-management provides an opportunity to leverage the lessons learnt to ensure a more individualised model of care for people with ILD.

Self-management interventions for people with pulmonary fibrosis: a scoping review.

BACKGROUND: The most effective method for encouraging self-management in individuals with pulmonary fibrosis (PF) is unclear. This review aimed to identify common self-management components, the outcome measures used and the impact of these components in PF. METHODS: A scoping review was conducted according to the Joanna Briggs Institute Manual for Evidence Synthesis using Medline, Embase, PsychInfo, CINAHL and the Cochrane Central Register of Controlled Trials. Eligible studies included those with educational, behavioural or support components aimed at facilitating self-management among adults with PF and employed quantitative and/or qualitative methods. RESULTS: 87 studies were included. Common self-management components included education (78%), managing physical symptoms (66%) and enhancing psychosocial wellbeing (54%). Components were predominantly delivered in a pulmonary rehabilitation setting (71%). No studies tested a PF-specific self-management package. Common outcome measures were 6-min walk distance (60%), St George's Respiratory Questionnaire (37%) and the Medical Research Council Dyspnoea scale (34%). Clinically significant improvements in these outcomes were seen in ≥50% of randomised controlled trials. Qualitative data highlighted the importance of healthcare professional and peer support and increased confidence in managing PF. CONCLUSION: Self-management components are commonly incorporated into pulmonary rehabilitation programmes rather than being offered as standalone packages. Future research should focus on testing PF-specific self-management packages and employ standardised outcome assessments that include self-efficacy and health-related behaviours.

Barriers to and facilitators of the use of oxygen therapy in people living with an interstitial lung disease: a systematic review of qualitative evidence.

BACKGROUND: Oxygen therapy is prescribed to treat hypoxaemia in people with interstitial lung disease (ILD); however, uptake and adherence remain an ongoing challenge. This systematic review aimed to identify the barriers to and facilitators of use of oxygen therapy in people with ILD, caregivers and health professionals. METHODS: A systematic search for qualitative literature was undertaken using five electronic databases (MEDLINE, CINAHL, Embase, PsycINFO, PubMed). Qualitative analysis identified themes that were mapped to the Theoretical Domains Framework and the Consolidated Framework for Implementation Research and classified as barriers, facilitators or both. RESULTS: A total of 13 studies were eligible for inclusion. Commonly represented domains were associated with the design of the oxygen delivery system, the associated cost, financing, stigmatisation, the physical environment and the individual needs that acted as barriers to and facilitators of the optimisation of oxygen therapy. CONCLUSION: Effective implementation of oxygen therapy in ILD requires more robust evidence to strengthen international guidelines, sustainable and equitable funding models, and improved oxygen delivery systems that meet the needs of users. Increased information and support for users will be critical to optimise the uptake and outcomes of this important therapy.

Understanding the telehealth experience of care by people with ILD during the COVID-19 pandemic: what have we learnt?

INTRODUCTION: The COVID-19 pandemic resulted in a rapid transformation of health services. This study aimed to understand the experiences of healthcare by people with interstitial lung disease (ILD), to inform future service delivery. METHODS: Four specialist clinics in tertiary centres in Australia (Victoria:2 sites; New South Wales: 1 site; Western Australia: 1 site) recruited patients with ILD during an 8-week period from March 2021. Participants completed a COVID-specific questionnaire focused on health-related experiences during 2020. RESULTS: Ninety nine (65% of 153) participants completed the questionnaire. 47% had idiopathic pulmonary fibrosis or connective tissue disease-associated ILD, 62% were female and the average age was 66 years. Whilst 56% rated their overall health in 2020 as the same as months prior, 38% indicated a worsening in health attributed to reduced physical activity and fear of contracting the virus. Access to healthcare professionals was 'good' in 61%, and 'fair-to-poor' for 37% due to missed respiratory assessments, with telehealth (mainly telephone) being perceived as less effective. 89% had contact with respiratory physicians, 68% with general practitioners, predominantly via telephone, with few video consultations. High satisfaction with care was reported by 78%, with lower satisfaction attributed to delays in assessments, disruption to usual services such as pulmonary rehabilitation, and dissatisfaction with telehealth. CONCLUSION: People with ILD were generally satisfied with their care during 2020, however reduced access to healthcare professionals was challenging for those experiencing a deterioration in health. Telehealth was largely well received but did not always meet the needs of people with ILD particularly when unwell.

Evaluation of Maternal Infection During Pregnancy and Childhood Leukemia Among Offspring in Denmark.

Importance: Maternal infection is common during pregnancy and is an important potential cause of fetal genetic and immunological abnormalities. Maternal infection has been reported to be associated with childhood leukemia in previous case-control or small cohort studies. Objective: To evaluate the association of maternal infection during pregnancy with childhood leukemia among offspring in a large study. Design, Setting, and Participants: This population-based cohort study used data from 7 Danish national registries (including the Danish Medical Birth Register, the Danish National Patient Registry, the Danish National Cancer Registry, and others) for all live births in Denmark between 1978 and 2015. Swedish registry data for all live births between 1988 and 2014 were used to validate the findings for the Danish cohort. Data were analyzed from December 2019 to December 2021. Exposures: Maternal infection during pregnancy categorized by anatomic locations identified from the Danish National Patient Registry. Main Outcomes and Measures: The primary outcome was any leukemia; secondary outcomes were acute lymphoid leukemia (ALL) and acute myeloid leukemia (AML). Offspring childhood leukemia was identified in the Danish National Cancer Registry. Associations were first assessed in the whole cohort using Cox proportional hazards regression models, adjusted for potential confounders. A sibling analysis was performed to account for unmeasured familial confounding. Results: This study included 2 222 797 children, 51.3% of whom were boys. During the approximately 27 million person-years of follow-up (mean [SD], 12.0 [4.6] years per person), 1307 children were diagnosed with leukemia (ALL, 1050; AML, 165; or other, 92). Children born to mothers with infection during pregnancy had a 35% increased risk of leukemia (adjusted hazard ratio [HR], 1.35 [95% CI, 1.04-1.77]) compared with offspring of mothers without infection. Maternal genital and urinary tract infections were associated with a 142% and 65% increased risk of childhood leukemia, with HRs of 2.42 (95% CI, 1.50-3.92) and 1.65 (95% CI, 1.15-2.36), respectively. No association was observed for respiratory tract, digestive, or other infections. The sibling analysis showed comparable estimates to the whole-cohort analysis. The association patterns for ALL and AML were similar to that for any leukemia. No association was observed for maternal infection and brain tumors, lymphoma, or other childhood cancers. Conclusions and Relevance: In this cohort study of approximately 2.2 million children, maternal genitourinary tract infection during pregnancy was associated with childhood leukemia among offspring. If confirmed in future studies, our findings may have implications for understanding the etiology and developing preventive measures for childhood leukemia.

Developing a self-management package for pulmonary fibrosis: an international Delphi study.

Rationale: Self-management is considered as an important part of disease management for people with pulmonary fibrosis (PF), but there is a lack of consensus regarding what components should be included. This study aimed to attain consensus from experts in PF and people living with the disease on the essential components and format of a PF self-management package. Methods: A two-round Delphi process was conducted. In each round, a panel of experts completed an online survey to rate a range of components, formats and delivery methods, followed by an online patient focus group to integrate patient perspectives. Consensus was defined a priori. Results: 45 experts participated in Round 1 and 51 in Round 2. Both focus groups included six people with PF. 12 components were considered essential for self-management in PF: 1) understanding treatment options; 2) understanding and accessing clinical trials; 3) managing medications; 4) role of oxygen therapy; 5) role and importance of pulmonary rehabilitation and regular physical activity; 6) managing shortness of breath; 7) managing fatigue; 8) managing mood; 9) managing comorbidities; 10) smoking cessation advice and support; 11) accessing community support; and 12) how to communicate with others when living with PF. Both groups agreed that self-management in PF required individualisation, goal setting and feedback. Conclusion: This study identified 12 essential components and highlighted individualisation, goal setting and feedback in self-management of PF. The findings provide a basis for the development of PF self-management interventions.

Self-management for pulmonary fibrosis: Insights from people living with the disease and healthcare professionals.

OBJECTIVE: People with pulmonary fibrosis (PF) consider self-management essential for maintaining health. This study aims to explore the needs and expectations of PF self-management from the patient and healthcare professionals (HCPs) perspectives. METHODS: Semi-structured interviews were conducted with people with PF and HCPs. Purposive sampling was used to recruit participants. Thematic analysis was performed using the principles of grounded theory. RESULTS: 18 individuals with PF and 15 HCPs were interviewed. Common self-management components reported included exercise, nutrition, maintaining healthy mind, avoiding infections, recognising deterioration and seeking help, managing symptoms and treatments, social support, and end-of-life planning. Both groups felt that effective self-management required individualised strategies, supports, and reliable information. People with PF identified access to personal health data and self-acceptance as part of self-management. HCPs highlighted the importance of accessible supports and managing patient expectations of disease course and treatments. Some HCPs concerned about missed detection of deterioration and suggested that self-management strategies for PF may differ to other lung diseases. CONCLUSION: This study identified components important for self-management in PF and provides a basis for designing a PF self-management package. PRACTICE IMPLICATIONS: Self-management of PF can be facilitated with individualised support from HCPs and reliable information that is accessible.

Common maternal infections during pregnancy and childhood leukaemia in the offspring: findings from six international birth cohorts.

BACKGROUND: Previous epidemiological studies have found positive associations between maternal infections and childhood leukaemia; however, evidence from prospective cohort studies is scarce. We aimed to examine the associations using large-scale prospective data. METHODS: Data were pooled from six population-based birth cohorts in Australia, Denmark, Israel, Norway, the UK and the USA (recruitment 1950s-2000s). Primary outcomes were any childhood leukaemia and acute lymphoblastic leukaemia (ALL); secondary outcomes were acute myeloid leukaemia (AML) and any childhood cancer. Exposures included maternal self-reported infections [influenza-like illness, common cold, any respiratory tract infection, vaginal thrush, vaginal infections and urinary tract infection (including cystitis)] and infection-associated symptoms (fever and diarrhoea) during pregnancy. Covariate-adjusted hazard ratio (HR) and 95% confidence interval (CI) were estimated using multilevel Cox models. RESULTS: Among 312 879 children with a median follow-up of 13.6 years, 167 leukaemias, including 129 ALL and 33 AML, were identified. Maternal urinary tract infection was associated with increased risk of any leukaemia [HR (95% CI) 1.68 (1.10-2.58)] and subtypes ALL [1.49 (0.87-2.56)] and AML [2.70 ([0.93-7.86)], but not with any cancer [1.13 (0.85-1.51)]. Respiratory tract infection was associated with increased risk of any leukaemia [1.57 (1.06-2.34)], ALL [1.43 (0.94-2.19)], AML [2.37 (1.10-5.12)] and any cancer [1.33 (1.09-1.63)]; influenza-like illness showed a similar pattern but with less precise estimates. There was no evidence of a link between other infections and any outcomes. CONCLUSIONS: Urinary tract and respiratory tract infections during pregnancy may be associated with childhood leukaemia, but the absolute risk is small given the rarity of the outcome.

Barriers and facilitators to best care for idiopathic pulmonary fibrosis in Australia.

BACKGROUND AND OBJECTIVE: In Australia, little is known about delivery of care for people with idiopathic pulmonary fibrosis (IPF). This study examined the organization of IPF care across Australia, how it aligns with guidance for best practice, and identified barriers and facilitators to best care. METHODS: Data on the organization of IPF care in Australia were collected from public hospitals using a study-specific questionnaire between February and July 2020. Semi-structured telephone interviews were conducted with respiratory physicians from around Australia between April and December 2020. Interviews were transcribed verbatim and thematic analysis was undertaken. RESULTS: Almost all hospitals (n = 38, 97%) held multidisciplinary meetings (MDMs) for diagnosing IPF, with 90% of multidisciplinary teams including expert respiratory physicians and radiologists; however, rheumatologists, interstitial lung disease nurses and a histopathologist were often not available. More than 90% of institutions had access to oxygen therapy, pulmonary rehabilitation and advanced care planning, but access to psychological support and clinical trials was limited (53% and 58%, respectively). Fifteen respiratory physicians (27% regional) were interviewed. Approaches to diagnosis, treatment and access to referral services were generally consistent with best practice guidance; however, regional respondents reported barriers related to inadequate staffing, lack of a nurse coordinator, inadequate access to clinical trials and funding models. Telehealth technologies were perceived as facilitators to best care. CONCLUSION: Clinical management of IPF in Australia generally aligns with best practice guidance, but there may be some inequity of access to specialist services, particularly in regional areas, that should be addressed to ensure optimal care for all.

Top 10 research priorities for people living with pulmonary fibrosis, their caregivers, healthcare professionals and researchers.

INTRODUCTION: People with pulmonary fibrosis (PF) experience a high symptom burden, reduced quality of life and a shortened lifespan. Treatment options are limited and little is known about what patients, caregivers and healthcare professionals (HCPs)/researchers consider as the most important research priorities. This study aimed to identify the top 10 research priorities for PF across all stakeholders. METHODS: Participants included people with PF, caregivers and HCPs/researchers involved with PF. The research priority setting exercise involved three stages: (1) identifying priorities using an open-ended questionnaire and thematic analysis, (2) development of specific research questions at a face-to-face workshop, and (3) online ranking of research questions to identify the top 10 research priorities using nominal group ranking method. RESULTS: 196 participants completed stage 1 generating 560 questions and 14 research themes were identified. Stage 2 involved 32 participants and generated 53 indicative questions from which 39 were used for the final ranking. Stage 3 was completed by 270 participants. The top ranked priorities focussed on medications to reverse scarring in the lungs (ranked 1st), improving lung function (ranked 2nd, 6th and 8th), interventions aimed at alleviating symptoms (ranked 5th and 7th), prevention of PF (ranked 3rd and 4th) and the best exercise programme for PF (ranked 10th). There was good consensus among patients/carers and HCPs/researchers on the top 10 priorities, however, causes of acute exacerbations and early diagnosis for improving survival, was ranked higher by HCPs/researchers. CONCLUSION: Interventions for preserving lung health and alleviation of symptom burden were top research priorities for PF stakeholders.

Home-based or remote exercise testing in chronic respiratory disease, during the COVID-19 pandemic and beyond: A rapid review.

OBJECTIVES: To identify exercise tests that are suitable for home-based or remote administration in people with chronic lung disease. METHODS: Rapid review of studies that reported home-based or remote administration of an exercise test in people with chronic lung disease, and studies reporting their clinimetric (measurement) properties. RESULTS: 84 studies were included. Tests used at home were the 6-minute walk test (6MWT, two studies), sit-to-stand tests (STS, five studies), Timed Up and Go (TUG, 4 studies) and step tests (two studies). Exercise tests administered remotely were the 6MWT (two studies) and step test (one study). Compared to centre-based testing the 6MWT distance was similar when performed outdoors but shorter when performed at home (two studies). The STS, TUG and step tests were feasible, reliable (intra-class correlation coefficients >0.80), valid (concurrent and known groups validity) and moderately responsive to pulmonary rehabilitation (medium effect sizes). These tests elicited less desaturation than the 6MWT, and validated methods to prescribe exercise were not reported. DISCUSSION: The STS, step and TUG tests can be performed at home, but do not accurately document desaturation with walking or allow exercise prescription. Patients at risk of desaturation should be prioritised for centre-based exercise testing when this is available.

Residential proximity to agriculture and risk of childhood leukemia and central nervous system tumors in the Danish national birth cohort.

BACKGROUND: Living in an agricultural area or on farms has been associated with increased risk of childhood cancer but few studies have evaluated specific agricultural exposures. We prospectively examined residential proximity to crops and animals during pregnancy and risk of childhood leukemia and central nervous system (CNS) tumors in Denmark. METHODS: The Danish National Birth Cohort (DNBC) consists of 91,769 pregnant women (96,841 live-born children) enrolled in 1996-2003. For 61 childhood leukemias and 59 CNS tumors <15 years of age that were diagnosed through 2014 and a ~10% random sample of the live births (N = 9394) with geocoded addresses, we linked pregnancy addresses to crop fields and animal farm locations and estimated the crop area (hectares [ha]) and number of animals (standardized by their nitrogen emissions) by type within 250 meters (m), 500 m, 1000 m, and 2000 m of the home. We also estimated pesticide applications (grams, active ingredient) based on annual sales data for nine herbicides and one fungicide that were estimated to have been applied to >30% of the area of one or more crop. We used Cox proportional hazard models (weighted to the full cohort) to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association of childhood leukemia and CNS tumors with crop area, animals, and pesticide applications adjusted for gender and maternal age. RESULTS: Sixty-three percent of mothers had crops within 500 m of their homes during pregnancy; winter and spring cereals were the major crop types. Compared to mothers with no crops <500 m, we found increasing risk of childhood leukemia among offspring of mothers with increasing crop area near their home (highest tertile >24 ha HR: 2.0, CI:1.02-3.8), which was stronger after adjustment for animals (within 1000 m) (HR: 2.6, CI:1.02-6.8). We also observed increased risk for grass/clover (highest tertile >1.1 ha HR: 3.1, CI:1.2-7.7), peas (>0 HR: 2.4, CI: 1.02-5.4), and maize (>0 HR: 2.8, CI: 1.1-6.9) in animal-adjusted models. We found no association between number of animals near homes and leukemia risk. Crops, total number of animals, and hogs within 500 m of the home were not associated with CNS tumors but we observed an increased risk with >median cattle compared with no animals in crop-adjusted models (HR = 2.2, CI: 1.02-4.9). In models adjusted for total animals, the highest tertiles of use of three herbicides and one fungicide were associated with elevated risk of leukemia but no associations were statistically significant; there were no associations with CNS tumors. CONCLUSIONS: Risk of childhood leukemia was associated with higher crop area near mothers' homes during pregnancy; CNS tumors were associated with higher cattle density. Quantitative estimates of crop pesticides and other agricultural exposures are needed to clarify possible reasons for these increased risks.

The supportive care needs of people living with pulmonary fibrosis and their caregivers: a systematic review.

BACKGROUND: People with pulmonary fibrosis often experience a protracted time to diagnosis, high symptom burden and limited disease information. This review aimed to identify the supportive care needs reported by people with pulmonary fibrosis and their caregivers. METHODS: A systematic review was conducted according to PRISMA guidelines. Studies that investigated the supportive care needs of people with pulmonary fibrosis or their caregivers were included. Supportive care needs were extracted and mapped to eight pre-specified domains using a framework synthesis method. RESULTS: A total of 35 studies were included. The most frequently reported needs were in the domain of information/education, including information on supplemental oxygen, disease progression and prognosis, pharmacological treatments and end-of-life planning. Psychosocial/emotional needs were also frequently reported, including management of anxiety, anger, sadness and fear. An additional domain of "access to care" was identified that had not been specified a priori; this included access to peer support, psychological support, specialist centres and support for families of people with pulmonary fibrosis. CONCLUSION: People with pulmonary fibrosis report many unmet needs for supportive care, particularly related to insufficient information and lack of psychosocial support. These data can inform the development of comprehensive care models for people with pulmonary fibrosis and their loved ones.

Perinatal photoperiod and childhood cancer: pooled results from 182,856 individuals in the international childhood cancer cohort consortium (I4C).

Experimental evidence suggests that perinatal light imprinting of circadian clocks and systems may affect downstream physiology and cancer risk in later life. For humans, the predominant circadian stimulus is the daily light-dark cycle. Herein, we explore associations between perinatal photoperiod characteristics (photoperiod: duration of daylight as determined by time-of-year and location) and childhood cancer risk. We use pooled data on 182,856 mothers and babies from prospective birth cohorts in six countries (Australia, Denmark, Israel, Norway, UK, USA) within the International Childhood Cancer Cohort Consortium (I4C). Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). In line with predicted differential dose-responses, restricted cubic splines indicate a potential non-linear, non-monotonic relationship between perinatal mean daily photoperiod (0-24 h) and childhood cancer risk. In a restricted analysis of 154,121 individuals who experienced third trimester photoperiods exclusively within the 8-16-h range, the relative risk of developing childhood cancer decreased by 9% with every hour increase in third trimester mean daily photoperiod [HR: 0.91 (95%CIs: 0.84-0.99)]. In conclusion, in this first study of perinatal photoperiod and childhood cancer, we detected an inverse ["protective"] linear association between third trimester mean daily photoperiod and childhood cancer risk in the 8-16-h set of the total study population. Limited statistical power impeded the investigation of risks with individuals exposed to more extreme photoperiods. Future studies are needed to confirm differential photoperiod-associated risks and further investigations into the hypothesized circadian imprinting mechanism are warranted.

Peer Connect Service for people with pulmonary fibrosis in Australia: Participants' experiences and process evaluation.

BACKGROUND AND OBJECTIVE: People living with pulmonary fibrosis (PF) report unmet needs for information and support. Lung Foundation Australia (LFA) have developed the Peer Connect Service to facilitate telephone support for people with PF across Australia. This project documented the experiences of participants and the resources required to support the service. METHODS: Consenting participants took part in semi-structured interviews by telephone. Primary peers (peers who agreed to initiate contact) and secondary peers (eligible patients who sought a peer match) were interviewed. Thematic analysis was undertaken by two independent researchers. Data were collected on the number of matches and contacts required to establish each match. RESULTS: Interviews were conducted with 32 participants (16 primary peers, 15 secondary peers and 1 who was both), aged from 53 to 89 years with 56% being male. Major themes included the value of shared experiences, providing mutual support and the importance of shared personal characteristics (e.g. gender and hobbies) in allowing information and emotional support needs to be met. Participants saw face-to-face contact with peers as highly desirable whilst acknowledging the practical difficulties. Primary peers were cognizant that their role was not to provide medical advice but to listen and share experiences. In the 12-month period, 60 peer matches were made, each match requiring a minimum of seven staff contacts. CONCLUSION: The Peer Connect Service provides a unique opportunity for people with PF to share experiences and offer mutual support. This telephone matching model may be useful in providing peer support for individuals with rare diseases who are geographically dispersed.

Parental occupational exposure to pesticides, animals and organic dust and risk of childhood leukemia and central nervous system tumors: Findings from the International Childhood Cancer Cohort Consortium (I4C).

Parental occupational exposures to pesticides, animals and organic dust have been associated with an increased risk of childhood cancer based mostly on case-control studies. We prospectively evaluated parental occupational exposures and risk of childhood leukemia and central nervous system (CNS) tumors in the International Childhood Cancer Cohort Consortium. We pooled data on 329,658 participants from birth cohorts in five countries (Australia, Denmark, Israel, Norway and United Kingdom). Parental occupational exposures during pregnancy were estimated by linking International Standard Classification of Occupations-1988 job codes to the ALOHA+ job exposure matrix. Risk of childhood (<15 years) acute lymphoblastic leukemia (ALL; n = 129), acute myeloid leukemia (AML; n = 31) and CNS tumors (n = 158) was estimated using Cox proportional hazards models to generate hazard ratios (HR) and 95% confidence intervals (CI). Paternal exposures to pesticides and animals were associated with increased risk of childhood AML (herbicides HR = 3.22, 95% CI = 0.97-10.68; insecticides HR = 2.86, 95% CI = 0.99-8.23; animals HR = 3.89, 95% CI = 1.18-12.90), but not ALL or CNS tumors. Paternal exposure to organic dust was positively associated with AML (HR = 2.38 95% CI = 1.12-5.07), inversely associated with ALL (HR = 0.55, 95% CI = 0.31-0.99) and not associated with CNS tumors. Low exposure prevalence precluded evaluation of maternal pesticide and animal exposures; we observed no significant associations with organic dust exposure. This first prospective analysis of pooled birth cohorts and parental occupational exposures provides evidence for paternal agricultural exposures as childhood AML risk factors. The different risks for childhood ALL associated with maternal and paternal organic dust exposures should be investigated further.

Maternal Infection in Pregnancy and Childhood Leukemia: A Systematic Review and Meta-analysis.

OBJECTIVE: To summarize the published evidence regarding the association between maternal infection during pregnancy and childhood leukemia. STUDY DESIGN: In this systematic review and meta-analysis (PROSPERO number, CRD42018087289), we searched PubMed and Embase to identify relevant studies. We included human studies that reported associations of at least one measure of maternal infection during pregnancy with acute lymphoblastic leukemia (ALL) or all childhood leukemias in the offspring. One reviewer extracted the data first using a standardized form, and the second reviewer independently checked the data for accuracy. Two reviewers used the Newcastle-Ottawa Scale to assess the quality of included studies. We conducted random effects meta-analyses to pool the ORs of specific type of infection on ALL and childhood leukemia. RESULTS: This review included 20 studies (ALL, n = 15; childhood leukemia, n = 14) reported in 32 articles. Most (>65%) included studies reported a positive association between infection variables and ALL or childhood leukemia. Among specific types of infection, we found that influenza during pregnancy was associated with higher risk of ALL (pooled OR, 3.64; 95% CI, 1.34-9.90) and childhood leukemia (pooled OR, 1.77; 95% CI, 1.01-3.11). Varicella (pooled OR, 10.19; 95% CI, 1.98-52.39) and rubella (pooled OR, 2.79; 95% CI, 1.16-6.71) infections were also associated with higher childhood leukemia risk. CONCLUSIONS: Our findings suggest that maternal infection during pregnancy may be associated with a higher risk of childhood leukemia.

The association between birth order and childhood leukemia may be modified by paternal age and birth weight. Pooled results from the International Childhood Cancer Cohort Consortium (I4C).

The "delayed infection hypothesis" states that a paucity of infections in early childhood may lead to higher risks of childhood leukemia (CL), especially acute lymphoblastic leukemia (ALL). Using prospectively collected data from six population-based birth cohorts we studied the association between birth order (a proxy for pathogen exposure) and CL. We explored whether other birth or parental characteristics modify this association. With 2.2 × 106 person-years of follow-up, 185 CL and 136 ALL cases were ascertained. In Cox proportional hazards models, increasing birth order (continuous) was inversely associated with CL and ALL; hazard ratios (HR) = 0.88, 95% confidence interval (CI): (0.77-0.99) and 0.85: (0.73-0.99), respectively. Being later-born was associated with similarly reduced hazards of CL and ALL compared to being first-born; HRs = 0.78: 95% CI: 0.58-1.05 and 0.73: 0.52-1.03, respectively. Successive birth orders were associated with decreased CL and ALL risks (P for trend 0.047 and 0.055, respectively). Multivariable adjustment somewhat attenuated the associations. We found statistically significant and borderline interactions between birth weight (p = 0.024) and paternal age (p = 0.067), respectively, in associations between being later-born and CL, with the lowest risk observed for children born at <3 kg with fathers aged 35+ (HR = 0.18, 95% CI: 0.06-0.50). Our study strengthens the theory that increasing birth order confers protection against CL and ALL risks, but suggests that this association may be modified among subsets of children with different characteristics, notably advanced paternal age and lower birth weight. It is unclear whether these findings can be explained solely by infectious exposures.