The Risk of Cancer following Hospitalization for Infection in Infancy: A Population-Based Cohort Study

Mode of Delivery, Birth Characteristics, and Early-Onset Non-Hodgkin Lymphoma in a Population-Based Case-Control Study

BACKGROUND

The etiology of non-Hodgkin lymphoma (NHL) in children and in adolescents and young adults (AYA) is not well understood.

METHODS

We evaluated potential associations between mode of delivery, birth characteristics, and NHL risk in a population-based case-control study, which included 3,064 cases of NHL [490 with Burkitt lymphoma, 981 with diffuse large B-cell lymphoma (DLBCL), and 978 with T-cell NHL) diagnosed at the age of 0 to 37 years in California during 1988 to 2015 and 153,200 controls frequency matched on year of birth. Odds ratios (OR) and 95% confidence intervals (CI) were estimated from an unconditional multivariable logistic regression model that included year of birth and birth characteristics.

RESULTS

Individuals born via cesarean section had a decreased risk of pediatric Burkitt lymphoma (age 0-14 years; OR = 0.71, 95% CI: 0.51-0.99) and pediatric T-cell NHL (OR = 0.73, 95% CI: 0.55-0.97) compared with those born vaginally. Having a birth order of second (OR = 0.73, 95% CI: 0.57-0.93) or third or higher (OR = 0.76, 95% CI: 0.58-0.99) was associated with a lower risk of pediatric T-cell NHL compared with first-borns. AYA (age 15-37 years) with a heavier birthweight had an elevated risk of DLBCL (OR for each kg = 1.16, 95% CI: 1.00-1.35). Associations between other birth characteristics, including plurality, maternal age, maternal education, and NHL risk, also exhibited variations across subgroups based on age of diagnosis and histologic subtype.

CONCLUSIONS

These findings support a role of mode of delivery and birth characteristics in the etiology of early-onset NHL.

IMPACT

This study underscores the etiologic heterogeneity of early-onset NHL.

A systematic review and meta-analysis of the association between childhood infections and the risk of childhood acute lymphoblastic leukaemia

Background:

To determine whether childhood infections were associated with the development of childhood acute lymphoblastic leukaemia (ALL).

Methods:

We included studies that assessed any infection in childhood prior to the diagnosis of ALL in children aged 0–19 years compared to children without cancer. The primary analysis synthesised any infection against the odds of ALL, and secondary analyses assessed the frequency, severity, timing of infections, and specific infectious agents against the odds of ALL. Subgroup analyses by data source were investigated.

Results:

In our primary analysis of 12 496 children with ALL and 2 356 288 children without ALL from 38 studies, we found that any infection was not associated with ALL (odds ratio (OR)=1.10, 95% CI: 0.95–1.28). Among studies with laboratory-confirmed infections, the presence of infections increased the odds of ALL by 2.4-fold (OR=2.42, 95% CI: 1.54–3.82). Frequency, severity, and timing of infection were not associated with ALL.

Conclusions:

The hypothesis put forward by Greaves and others about an infectious aetiology are neither confirmed nor refuted and the overall evidence remains inadequate for good judgement. The qualitative difference in the subgroup effects require further study, and future research will need to address the challenges in measuring infectious exposures.

Ethnic variation in medical and lifestyle risk factors for B cell non-Hodgkin lymphoma: A case-control study among Israelis and Palestinians

Background

Risk factors for B-cell non-Hodgkin lymphoma (B-NHL) have not been assessed among Palestinian Arabs (PA) and Israeli Jews (IJ).

Methods

In a case-control study we investigated self-reported medical and lifestyle exposures, reporting odds ratios (ORs) and 95% confidence intervals [CIs], by ethnicity, for overall B-NHL and subtypes.

Results

We recruited 823 cases and 808 healthy controls. Among 307 PA/516 IJ B-NHL cases (mean age at diagnosis = 51 [±17] versus 60 [±15] years, respectively) subtype distributions differed, with diffuse large B-cell lymphoma (DLBCL) being prominent among PA (71%) compared to IJ (41%); follicular lymphoma (FL), was observed in 14% versus 28%, and marginal zone lymphoma, in 2% versus 14%, respectively. Overall B-NHL in both populations was associated with recreational sun exposure OR = 1.43 [CI:1.07–1.91], black hair-dye use OR = 1.70 [CI:1.00–2.87], hospitalization for infection OR = 1.68 [CI:1.34–2.11], and first-degree relative with hematopoietic cancer, OR = 1.69 [CI:1.16–2.48]. An inverse association was noted with alcohol use, OR = 0.46 [CI:0.34–0.62]. Subtype-specific exposures included smoking (FL, OR = 1.46 [CI:1.01–2.11]) and >monthly indoor pesticide use (DLBCL, OR = 2.01 [CI:1.35–3.00]). Associations observed for overall B-NHL in PA only included: gardening OR = 1.93 [CI:1.39–2.70]; history of herpes, mononucleosis, rubella, blood transfusion (OR>2.5, P<0.01 for all); while for IJ risk factors included growing fruits and vegetables, OR = 1.87 [CI:1.11–3.15]; and self-reported autoimmune diseases, OR = 1.99 [CI:1.34–2.95].

Conclusions

In these geographically proximate populations we found some unique risk factors for B-NHL. Heterogeneity in the observed associations by ethnicity could reflect differences in lifestyle, medical systems, and reporting patterns, while variations by histology infer specific etiologic factors for lymphoma subtypes.

Linking databases on perinatal health: a review of the literature and current practices in Europe

Background: International comparisons of perinatal health indicators are complicated by the heterogeneity of data sources on pregnancy, maternal and neonatal outcomes. Record linkage can extend the range of data items available and thus can improve the validity and quality of routine data. We sought to assess the extent to which data are linked routinely for perinatal health research and reporting. Methods: We conducted a systematic review of the literature by searching PubMed for perinatal health studies from 2001 to 2011 based on linkage of routine data (data collected continuously at various time intervals). We also surveyed European health monitoring professionals about use of linkage for national perinatal health surveillance. Results: 516 studies fit our inclusion criteria. Denmark, Finland, Norway and Sweden, the US and the UK contributed 76% of the publications; a further 29 countries contributed at least one publication. Most studies linked vital statistics, hospital records, medical birth registries and cohort data. Other sources were specific registers for: cancer (70), congenital anomalies (56), ART (19), census (19), health professionals (37), insurance (22) prescription (31), and level of education (18). Eighteen of 29 countries (62%) reported linking data for routine perinatal health monitoring. Conclusion: Research using linkage is concentrated in a few countries and is not widely practiced in Europe. Broader adoption of data linkage could yield substantial gains for perinatal health research and surveillance.

Breastfeeding and the risk of childhood Hodgkin lymphoma: a systematic review and meta-analysis

PURPOSE

Numerous observational epidemiological studies have evaluated associations between breastfeeding and the risk of childhood Hodgkin lymphoma; however, the existing results are inconsistent. We therefore conducted a systematic review and meta-analysis.

METHODS

Medical literature was searched in the Pubmed and Embase databases to identify all English-language relevant studies up to April 10, 2013. Reference lists were thereafter hand-searched for additional articles. Studies that reported relative risk ratios (RRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were included. This meta-analysis was conducted in accordance with the guidelines for the meta-analysis of observational studies in epidemiology.

RESULTS

We finally included 10 case-control studies in our meta-analysis, involving 1,618 childhood Hodgkin lymphoma cases and 8,181 controls. Overall, we did found a borderline significant association between breastfeeding and reduced risk of childhood Hodgkin lymphoma comparing ever breastfed children to never breastfed children (pooled OR =0.79; 95%CI, 0.58-1.08; P=0.13), with limited evidence for between-study heterogeneity (P =0.12, I2 = 35.70%).

CONCLUSION

There is limited evidence for an inverse association between breastfeeding and risk of childhood Hodgkin lymphoma.

Childhood Hodgkin's lymphoma, non-Hodgkin's lymphoma and factors related to the immune system: the Escale Study (SFCE)

The study investigated the role of factors considered related to the early stimulation of the immune system in the aetiology of childhood lymphoma. The national registry-based case-control study, Escale, was carried out in France over the period 2003-2004. Population controls were frequency matched with the cases on age and gender. Data were obtained from structured telephone questionnaires administered to mothers. Odds ratios (ORs) were estimated using unconditional regression models adjusted for potential confounders. Data from 128 cases of Hodgkin's lymphoma (HL) aged 5-14 years, 164 cases of non-Hodgkin's lymphoma (NHL) aged 2-14 years and 1,312 controls were analyzed. Negative associations were observed between HL and day care attendance [OR = 0.5 (0.2-1.2)] and between HL and repeated early common infections among non-breastfed children [OR = 0.3 (.2-0.7), p = 0.003] [OR for breastfed children: 1.0 (.5-2.1)], but not for the other factors investigated. Negative associations were observed between NHL and birth order 3 or more [OR = 0.7 (0.4-1.1)], prolonged breastfeeding [OR = 0.5 (0.3-1.0)], regular contact with farm animals [OR = 0.5 (0.3-1.0)], frequent farm visits in early life [OR = 0.6 (0.4-1.1)] and history of asthma [OR = 0.6 (0.3-1.1)]. In conclusion, the results partly support the hypothesis that an abnormal maturation of the immune system may play a role in childhood HL or NHL, and call for further investigations.

Racial differences in chronic immune stimulatory conditions and risk of non-Hodgkin's lymphoma in veterans from the United States

PURPOSE

To examine underlying etiologic factors that may explain the racial disparity in non-Hodgkin's lymphoma (NHL) incidence patterns.

PATIENTS AND METHODS

We assessed immune-related conditions and risk of developing NHL among more than 4 million hospitalized US veterans including 9,496 patients with NHL (7,999 white patients and 1,497 black patients) with up to 26 years of follow-up. We used time-dependent Poisson regression to estimate rate ratios (RRs) and 95% CIs for NHL risk among patients with a history of specific autoimmune diseases, infections, and allergies compared with patients without such history, adjusting for attained age, calendar year, race, number of hospital visits, and time between study entry and exit.

RESULTS

Patients with infectious conditions had an increased risk of developing NHL (RR, 1.2; 95% CI, 1.1 to 1.2), particularly for gastrohepatic, genital, and systemic infectious conditions. Patients with autoimmune disease were generally more likely to develop NHL than patients without autoimmune disease, especially for conditions that typically present with detectable autoantibodies with systemic involvement (RR, 2.0; 95% CI, 1.8 to 2.2). Allergies were also associated with increased risk (RR, 1.4; 95% CI, 1.3 to 1.5). Although the risk of NHL was lower for blacks than whites (RR, 0.87; 95% CI, 0.82 to 0.92), blacks had a slightly higher risk of NHL associated with infections than whites (likelihood ratio test, P = .002) and a tendency toward higher risk associated with allergies (likelihood ratio test, P = .05). Risks associated with autoimmune conditions were similar by race (likelihood ratio test, P = .5).

CONCLUSION

The observed difference in NHL risk by race supports a role for race-related differences in genes regulating immune/inflammatory response.

Infection in infancy and subsequent risk of developing lymphoma in children and young adults

There is evidence that certain infections and autoimmunity predispose to the development of non-Hodgkin lymphomas (NHLs). A previous study reported that hospitalization for infections in infancy led to an increased risk of NHL. By using population-based registries in Sweden, we compared the rate of hospitalization for infections in infancy between lymphoma cases and matched controls for patients born since 1964. A history of infection was associated with a significantly increased risk of aggressive B-cell lymphomas (odds ratio 2.1, 95% confidence interval 1.11-4.04, P = .02). The specific infections involved were respiratory and intestinal. No effects were observed among cases of Hodgkin lymphoma. This association could result from the infection, its treatment, or could be a surrogate marker for underlying immune defects. Further studies are needed to determine whether this association is present among NHL occurring in older adults and if improved survival of patients with immune defects has contributed to the secular increases in incidence of NHLs.

Childhood acute leukemia, early common infections, and allergy: The ESCALE Study

This study investigated the role of factors considered related to early stimulation of the immune system in the etiology of childhood acute leukemia. The national registry-based case-control study ESCALE was carried out in France in 2003-2004. Population controls were frequency matched to cases on age and gender. Data were obtained from structured telephone questionnaires administered to mothers. Odds ratios were estimated using unconditional regression models adjusted for potential confounders. Included were 634 acute lymphoblastic leukemia cases, 86 acute myeloblastic leukemia cases, and 1,494 controls aged ≥1 year. Negative associations were observed between acute lymphoblastic leukemia and birth order (P for trend < 0.0001), attendance at a day-care center before age 1 year (odds ratio (OR) = 0.8, 95% confidence interval (CI): 0.6, 1.1), prolonged breastfeeding (OR = 0.7, 95% CI: 0.5, 1.0), repeated early common infections (OR = 0.7, 95% CI: 0.6, 0.9), regular contact with farm animals (OR = 0.6, 95% CI: 0.5, 0.8), frequent farm visits in early life (OR = 0.4, 95% CI: 0.3, 0.6), and history of asthma (OR = 0.7, 95% CI: 0.4, 1.0) or eczema (OR = 0.7, 95% CI: 0.6, 0.9). Results support the hypothesis that repeated early infections and asthma may play a role against childhood acute leukemia.