Reproductive factors, hormonal interventions, and gastric cancer risk in the Stomach cancer Pooling (StoP) Project

BACKGROUND

Gastric cancer incidence is higher in men, and a protective hormone-related effect in women is postulated. We aimed to investigate and quantify the relationship in the Stomach cancer Pooling (StoP) Project consortium.

METHODS

A total of 2,084 cases and 7,102 controls from 11 studies in seven countries were included. Summary odds ratios (ORs) and 95% confidence intervals (CIs) assessing associations of key reproductive factors and menopausal hormone therapy (MHT) with gastric cancer were estimated by pooling study-specific ORs using random-effects meta-analysis.

RESULTS

A duration of fertility of ≥ 40 years (vs. < 20), was associated with a 25% lower risk of gastric cancer (OR = 0.75; 95% CI: 0.58-0.96). Compared with never use, ever, 5-9 years and ≥ 10 years use of MHT in postmenopausal women, showed ORs of 0.73 (95% CI: 0.58-0.92), 0.53 (95% CI: 0.34-0.84) and 0.71 (95% CI: 0.50-1.00), respectively. The associations were generally similar for anatomical and histologic subtypes.

CONCLUSION

Our results support the hypothesis that reproductive factors and MHT use may lower the risk of gastric cancer in women, regardless of anatomical or histologic subtypes. Given the variation in hormones over the lifespan, studies should address their effects in premenopausal and postmenopausal women. Furthermore, mechanistic studies may inform potential biological processes.

JS08.7.A Integrative analysis of longitudinal genomic and non-genetic mechanisms of radiotherapy-resistance in glioma

Background

Radiotherapy (RT) is a mainstay in the treatment of glioma patients, but RT-resistance is common. We have recently identified RT-associated genomic small deletion signatures, marking tumors that have developed resistance. Here, we used longitudinal molecular profiles to explore non-genetic mechanisms of RT-resistance.

Material and Methods

We have analyzed the multi-omic Glioma Longitudinal Analysis (GLASS) dataset, integrating DNA and RNA sequencing datasets from primary and post-treatment gliomas.

Results

We classified tumors as harboring temozolomide-associated hypermutation based on mutational burden increase (HM), and RT-associated signature based on small deletion burden increase (RTscars). By deconvoluting RNA profiles into cell state fractions, we observed an increase of a proliferating stem-like (PSL) cell state in 50% of patients with a RTscars+ signature which was significantly higher than RTscars-/HM- patients (P=8e-04, Fisher’s exact). PSL cell state increase associated with worse overall survival outcomes (P=1.5e-03, log-rank). We observed a significant correlation between the expression change of E2F cell cycle regulator genes (R=0.91, P=6.7e-04, Pearson) and EZH2 (R=0.81, P=8.3e-03) with the increase in the PSL cell state, nominating the E2F/EZH2-pathway as regulator of the PSL cell state. Furthermore, the RTscars signature was associated with an increase in frameshift neoantigens and significantly higher neoantigen burden at recurrence (P=2.4e-02, Kruskal-Wallis). This was accompanied by a significantly higher post-treatment T-cell fraction in RTscars+ tumors (P=8.2e-04, Wilcox), suggesting an increased T-cell infiltration in these patients.

Conclusion

Our analyses revealed a longitudinal increase in the proliferating stem-like cell state associated with RT-resistance and nominates the cell cycle pathway as an actionable target. The RT-associated deletion signature (RTscars) correlated with increased frameshift-neoantigens and T-cell fractions at recurrence, suggesting a potential benefit of a combinatorial immune-targeted therapy in this specific patient population.

PL03.2.A Radiotherapy is associated with a deletion signature that contributes to poor outcomes in glioma patients

BACKGROUND

Diffuse gliomas are highly aggressive brain tumors that invariably relapse despite treatment with chemo- and radiotherapy. Treatment with alkylating chemotherapy can drive tumors to develop a hypermutator phenotype. In contrast, the genomic effects of radiation therapy (RT) remain largely unknown.

MATERIAL AND METHODS

We analyzed the mutational spectra following treatment with RT in whole genome or exome sequencing data from 190 paired primary-recurrent gliomas from the Glioma Longitudinal Analysis (GLASS) dataset and 3693 post-treatment metastatic tumors from the Hartwig Medical Foundation (HMF).

RESULTS

We identified a significant increase in the burden of small deletions following radiation therapy that was independent of other factors (P = 3e-03, multivariable log-linear regression). These novel deletions demonstrated distinct characteristics when compared to pre-existing deletions present prior to RT-treatment and deletions in RT-untreated tumors. Radiation therapy-acquired deletions were characterized by a larger deletion size (GLASS and HMF, P = 1.5e-04 and P = 6e-16, respectively; Mann-Whitney U test), an increased distance to repetitive DNA elements (P &lt; 2.2e-16, Kolmogorov-Smirnov test) and a lack of microhomology at breakpoints (P = 6.6e-05, paired Wilcoxon signed-rank test). Furthermore, mutational signature analysis confirmed the distinct genomic characteristics of RT-associated deletions when compared to deletions arising via homologous recombination deficiency or microsatellite instability.

These observations suggested that canonical non-homologous end joining (c-NHEJ) was the preferred pathway for DNA double strand break repair of RT-induced DNA damage. Furthermore, RT resulted in frequent chromosomal deletions and significantly increased frequencies of CDKN2A homozygous deletions in IDHmut glioma (P= 1.9e-05, Fisher’s exact test). Finally, a high burden of RT-associated deletions was associated with worse clinical outcomes (GLASS and HMF, P = 3.4e-02 and P &lt; 1e-04, respectively; log-rank test).

CONCLUSION

Our results collectively suggest that effective repair of RT-induced DNA damage is detrimental to patient survival and that inhibiting c-NHEJ may be a viable strategy for improving the cancer-killing effect of radiotherapy. Furthermore, CDKN2A homozygous deletion at recurrence may be leveraged as a promising clinical biomarker of RT-resistance in IDHmut glioma. Taken together, the identified genomic scars as a result of RT reflect a more aggressive tumor with increased levels of resistance to follow up treatments.

Pivoting to Childbirth at Home or in Freestanding Birth Centers in the US During COVID-19: Safety, Economics and Logistics

Birth-related decisions principally center on safety; giving birth during a pandemic brings safety challenges to a new level, especially when choosing the birth setting. Amid the COVID-19 crisis, the concurrent work furloughs, business failures, and mounting public and private debt have made prudent expenditures an inescapable second concern. This article examines the intersections of safety, economic efficiency, insurance, liability and birthing persons' needs that have become critical as the pandemic has ravaged bodies and economies around the world. Those interests, and the challenges and solutions discussed in this article, remain important even in less troubled times. Our economic analysis suggests that having an additional 10% of deliveries take place in private homes or freestanding birth centers could save almost $11 billion per year in the United States without compromising safety.

Fruits and vegetables intake and gastric cancer risk: A pooled analysis within the Stomach cancer Pooling Project

A low intake of fruits and vegetables is a risk factor for gastric cancer, although there is uncertainty regarding the magnitude of the associations. In our study, the relationship between fruits and vegetables intake and gastric cancer was assessed, complementing a previous work on the association betweenconsumption of citrus fruits and gastric cancer. Data from 25 studies (8456 cases and 21 133 controls) with information on fruits and/or vegetables intake were used. A two-stage approach based on random-effects models was used to pool study-specific adjusted (sex, age and the main known risk factors for gastric cancer) odds ratios (ORs) and the corresponding 95% confidence intervals (CIs). Exposure-response relations, including linear and nonlinear associations, were modeled using one- and two-order fractional polynomials. Gastric cancer risk was lower for a higher intake of fruits (OR: 0.76, 95% CI: 0.64-0.90), noncitrus fruits (OR: 0.86, 95% CI: 0.73-1.02), vegetables (OR: 0.68, 95% CI: 0.56-0.84), and fruits and vegetables (OR: 0.61, 95% CI: 0.49-0.75); results were consistent across sociodemographic and lifestyles categories, as well as study characteristics. Exposure-response analyses showed an increasingly protective effect of portions/day of fruits (OR: 0.64, 95% CI: 0.57-0.73 for six portions), noncitrus fruits (OR: 0.71, 95% CI: 0.61-0.83 for six portions) and vegetables (OR: 0.51, 95% CI: 0.43-0.60 for 10 portions). A protective effect of all fruits, noncitrus fruits and vegetables was confirmed, supporting further dietary recommendations to decrease the burden of gastric cancer.

A data mining approach to investigate food groups related to incidence of bladder cancer in the BLadder cancer Epidemiology and Nutritional Determinants International Study

At present, analysis of diet and bladder cancer (BC) is mostly based on the intake of individual foods. The examination of food combinations provides a scope to deal with the complexity and unpredictability of the diet and aims to overcome the limitations of the study of nutrients and foods in isolation. This article aims to demonstrate the usability of supervised data mining methods to extract the food groups related to BC. In order to derive key food groups associated with BC risk, we applied the data mining technique C5.0 with 10-fold cross-validation in the BLadder cancer Epidemiology and Nutritional Determinants study, including data from eighteen case-control and one nested case-cohort study, compromising 8320 BC cases out of 31 551 participants. Dietary data, on the eleven main food groups of the Eurocode 2 Core classification codebook, and relevant non-diet data (i.e. sex, age and smoking status) were available. Primarily, five key food groups were extracted; in order of importance, beverages (non-milk); grains and grain products; vegetables and vegetable products; fats, oils and their products; meats and meat products were associated with BC risk. Since these food groups are corresponded with previously proposed BC-related dietary factors, data mining seems to be a promising technique in the field of nutritional epidemiology and deserves further examination.

Occupational exposures and odds of gastric cancer: a StoP project consortium pooled analysis

BACKGROUND

Gastric cancer pathogenesis represents a complex interaction of host genetic determinants, microbial virulence factors and environmental exposures. Our primary aim was to determine the association between occupations/occupational exposures and odds of gastric cancer.

METHODS

We conducted a pooled-analysis of individual-level data harmonized from 11 studies in the Stomach cancer Pooling Project. Multivariable logistic regression was used to estimate the odds ratio (OR) of gastric cancer adjusted for relevant confounders.

RESULTS

A total of 5279 gastric cancer cases and 12 297 controls were analysed. There were higher odds of gastric cancer among labour-related occupations, including: agricultural and animal husbandry workers [odds ratio (OR) 1.33, 95% confidence interval (CI): 1.06-1.68]; miners, quarrymen, well-drillers and related workers (OR 1.70, 95% CI: 1.01-2.88); blacksmiths, toolmakers and machine-tool operators (OR 1.41, 95% CI: 1.05-1.89); bricklayers, carpenters and construction workers (OR 1.30, 95% CI: 1.06-1.60); and stationary engine and related equipment operators (OR 6.53, 95% CI: 1.41-30.19). The ORs for wood-dust exposure were 1.51 (95% CI: 1.01-2.26) for intestinal-type and 2.52 (95% CI: 1.46-4.33) for diffuse-type gastric cancer. Corresponding values for aromatic amine exposure were 1.83 (95% CI: 1.09-3.06) and 2.92 (95% CI: 1.36-6.26). Exposure to coal derivatives, pesticides/herbicides, chromium, radiation and magnetic fields were associated with higher odds of diffuse-type, but not intestinal-type gastric cancer.

CONCLUSIONS

Based on a large pooled analysis, we identified several occupations and related exposures that are associated with elevated odds of gastric cancer. These findings have potential implications for risk attenuation and could be used to direct investigations evaluating the impact of targeted gastric cancer prevention/early detection programmes based on occupation.

Meat intake and risk of gastric cancer in the Stomach cancer Pooling (StoP) project

The consumption of processed meat has been associated with noncardia gastric cancer, but evidence regarding a possible role of red meat is more limited. Our study aims to quantify the association between meat consumption, namely white, red and processed meat, and the risk of gastric cancer, through individual participant data meta-analysis of studies participating in the "Stomach cancer Pooling (StoP) Project". Data from 22 studies, including 11,443 cases and 28,029 controls, were used. Study-specific odds ratios (ORs) were pooled through a two-stage approach based on random-effects models. An exposure-response relationship was modeled, using one and two-order fractional polynomials, to evaluate the possible nonlinear association between meat intake and gastric cancer. An increased risk of gastric cancer was observed for the consumption of all types of meat (highest vs. lowest tertile), which was statistically significant for red (OR: 1.24; 95% CI: 1.00-1.53), processed (OR: 1.23; 95% CI: 1.06-1.43) and total meat (OR: 1.30; 95% CI: 1.09-1.55). Exposure-response analyses showed an increasing risk of gastric cancer with increasing consumption of both processed and red meat, with the highest OR being observed for an intake of 150 g/day of red meat (OR: 1.85; 95% CI: 1.56-2.20). This work provides robust evidence on the relation between the consumption of different types of meat and gastric cancer. Adherence to dietary recommendations to reduce meat consumption may contribute to a reduction in the burden of gastric cancer.

Oral bisphosphonate use and lung cancer incidence among postmenopausal women

Background

Bisphosphonates are common medications for the treatment of osteoporosis in older populations. Several studies, including the Women’s Health Initiative (WHI), have found inverse associations of bisphosphonate use with risk of breast and endometrial cancer, but little is known about its association with other common malignancies. The objective of this study was to evaluate the association of bisphosphonate use on the incidence of lung cancer in the WHI.

Patients and methods

The association between oral bisphosphonate use and lung cancer risk was examined in 151 432 postmenopausal women enrolled into the WHI in 1993–1998. At baseline and during follow-up, participants completed an inventory of regularly used medications including bisphosphonates.

Results

After a mean follow-up of 13.3 years, 2511 women were diagnosed with incident lung cancer. There was no evidence of a difference in lung cancer incidence between oral bisphosphonate users and never users (adjusted hazard ratio = 0.91; 95% confidence intervals, 0.80–1.04; P = 0.16). However, an inverse association was observed among those who were never smokers (hazard ratio = 0.57, 95% confidence interval, 0.39–0.84; P < 0.01).

Conclusion

In this large prospective cohort of postmenopausal women, oral bisphosphonate use was associated with significantly lower lung cancer risk among never smokers, suggesting bisphosphonates may have a protective effect against lung cancer. Additional studies are needed to confirm our findings.

The renin-angiotensin aldosterone system and osteoporosis: findings from the Women's Health Initiative

New users of RAAS inhibitors, including ACE inhibitors and ARBs, have a small increased risk for fracture in the first 3 years of use, with a reduced risk of fracture with longer duration of use.

INTRODUCTION

Pharmacological inhibitors of the renin-angiotensin aldosterone system (RAAS) are used to treat hypertension. However, the relationship of these medications to osteoporosis is inconsistent, and no study has included simultaneous measurements of both incident fractures and bone mineral density (BMD).

METHODS

The association of RAAS inhibitor use (n = 131,793) with incident fractures in new users of these medications in women in the Women's Health Initiative over a minimum median follow-up of 6.5 years was assessed by Cox proportional hazard models. The association of incident fractures by a cumulative duration of use of these medications (< 3 years.) and (> 3 years.) was also estimated. Subgroup analysis of fracture risk by RAAS inhibitor use confined to women with hypertension was also performed (n = 33,820). The association of RAAS inhibitor use with changes in BMD of the hip was estimated by linear regression in 8940 women with dual energy X-ray absorptiometry measurements.

RESULTS

There was no significant association between RAAS inhibitor use and all fractures in the final adjusted multivariable models including hip BMD (HR 0.86 (0.59, 1.24)). However, among users of RAAS inhibitors, including ACE inhibitors and angiotensin receptor blockers (ARBs), hazard ratios for all incident fracture sites in final multivariable models including hip BMD showed dramatic differences by duration of use, with short duration of use (3 years or less) associated with a marked increased risk for fracture (HR 3.28 (1.66, 6.48)) to (HR 6.23 (3.11, 12.46)) and use for more than 3 years associated with a reduced fracture risk (HR 0.40 (0.24, 0.68) to (HR 0.44 (0.20, 0.97)) . Findings were similar in the subgroup of women with a history of hypertension. There was no significant change in BMD of the hip by RAAS inhibitor use.

CONCLUSIONS

In postmenopausal women, use of RAAS inhibitors, including ACE inhibitors and ARBs, is associated with an increased risk for fracture among new users of these medications in the first 3 years of use. However, long-term use (> 3 years) is associated with a reduced risk. Consideration for fracture risk may be part of the decision-making process for initiation of these medications for other disease states.

Education and gastric cancer risk-An individual participant data meta-analysis in the StoP project consortium

Low socioeconomic position (SEP) is a strong risk factor for incidence and premature mortality from several cancers. Our study aimed at quantifying the association between SEP and gastric cancer (GC) risk through an individual participant data meta-analysis within the "Stomach cancer Pooling (StoP) Project". Educational level and household income were used as proxies for the SEP. We estimated pooled odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) across levels of education and household income by pooling study-specific ORs through random-effects meta-analytic models. The relative index of inequality (RII) was also computed. A total of 9,773 GC cases and 24,373 controls from 25 studies from Europe, Asia and America were included. The pooled OR for the highest compared to the lowest level of education was 0.60 (95% CI, 0.44-0.84), while the pooled RII was 0.45 (95% CI, 0.29-0.69). A strong inverse association was observed both for noncardia (OR 0.39, 95% CI, 0.22-0.70) and cardia GC (OR 0.47, 95% CI, 0.22-0.99). The relation was stronger among H. pylori negative subjects (RII 0.14, 95% CI, 0.04-0.48) as compared to H. pylori positive ones (RII 0.29, 95% CI, 0.10-0.84), in the absence of a significant interaction (p = 0.28). The highest household income category showed a pooled OR of 0.65 (95% CI, 0.48-0.89), while the corresponding RII was 0.40 (95% CI, 0.22-0.72). Our collaborative pooled-analysis showed a strong inverse relationship between SEP indicators and GC risk. Our data call for public health interventions to reduce GC risk among the more vulnerable groups of the population.

Alcohol intake and gastric cancer: Meta-analyses of published data versus individual participant data pooled analyses (StoP Project)

BACKGROUND

Individual participant data pooled analyses allow access to non-published data and statistical reanalyses based on more homogeneous criteria than meta-analyses based on systematic reviews. We quantified the impact of publication-related biases and heterogeneity in data analysis and presentation in summary estimates of the association between alcohol drinking and gastric cancer.

METHODS

We compared estimates obtained from conventional meta-analyses, using only data available in published reports from studies that take part in the Stomach Cancer Pooling (StoP) Project, with individual participant data pooled analyses including the same studies.

RESULTS

A total of 22 studies from the StoP Project assessed the relation between alcohol intake and gastric cancer, 19 had specific data for levels of consumption and 18 according to cancer location; published reports addressing these associations were available from 18, 5 and 5 studies, respectively. The summary odds ratios [OR, (95%CI)] estimate obtained with published data for drinkers vs. non-drinkers was 10% higher than the one obtained with individual StoP data [18 vs. 22 studies: 1.21 (1.07-1.36) vs. 1.10 (0.99-1.23)] and more heterogeneous (I²: 63.6% vs 54.4%). In general, published data yielded less precise summary estimates (standard errors up to 2.6 times higher). Funnel plot analysis suggested publication bias.

CONCLUSION

Meta-analyses of the association between alcohol drinking and gastric cancer tended to overestimate the magnitude of the effects, possibly due to publication bias. Additionally, individual participant data pooled analyses yielded more precise estimates for different levels of exposure or cancer subtypes.

Mode of birth in twins: data and reflections

Our primary objective was to compare neonatal and maternal outcomes in women with twin pregnancies, beyond 32 weeks, having a planned vaginal birth or a planned caesarean section (CS). This was a retrospective cohort study from a single tertiary centre over nine years. 534 sets of twins ≥32 + 0 weeks of gestation were included. 401 sets were planned vaginally and 133 sets were planned by CS. We compared a composite adverse perinatal outcome (perinatal mortality or serious neonatal morbidity; five minute APGAR score ≤4, neurological abnormality and need for intubation) and a composite maternal adverse outcome (major haemorrhage, trauma or infection) between the groups. There were no significant differences. Given the similarity of these results with several other larger studies of twin birth, we sought to look at reasons why there is still a rising rate of CS for twin births. We further make suggestions for keeping this rate to a sensible minimum. Impact statement What is already known on this subject? The largest randomised controlled study comparing planned vaginal birth with planned CSs for lower risk twins between 32 and 39 weeks of gestation, showed no added safety from planned CS. However, in most of the Western countries this conclusion has failed to increase the number of planned vaginal births for lower risk twins. What do the results of this study add? This observational study from a single tertiary centre provides external validation of the twin trial results in a practical day-to-day setting. It also provides insights as to how planned vaginal birth can be developed and maintained, with a key focus on safety and maternal participation in decision making. It does focus on consent and providing accurate data. What are the implications of these findings for clinical practice and/or further research? There are good grounds to encourage vaginal birth for low-risk twin pregnancies. The trend of rising caesarean rates in low-risk twin pregnancies worldwide will erode important skills for the conduct of vaginal births without any clear benefit for mothers or babies. The current situation demands careful thought about implementing innovative training opportunities for younger obstetricians. Finally, we need intelligent responses to many non-evidence-based factors which can drive clinical practice.

Alcohol consumption and gastric cancer risk-A pooled analysis within the StoP project consortium

An association between heavy alcohol drinking and gastric cancer risk has been recently reported, but the issue is still open to discussion and quantification. We investigated the role of alcohol drinking on gastric cancer risk in the "Stomach cancer Pooling (StoP) Project," a consortium of epidemiological studies. A total of 9,669 cases and 25,336 controls from 20 studies from Europe, Asia and North America were included. We estimated summary odds-ratios (ORs) and the corresponding 95% confidence intervals (CIs) by pooling study-specific ORs using random-effects meta-regression models. Compared with abstainers, drinkers of up to 4 drinks/day of alcohol had no increase in gastric cancer risk, while the ORs were 1.26 (95% CI, 1.08-1.48) for heavy (>4 to 6 drinks/day) and 1.48 (95% CI 1.29-1.70) for very heavy (>6 drinks/day) drinkers. The risk for drinkers of >4 drinks/day was higher in never smokers (OR 1.87, 95% CI 1.35-2.58) as compared with current smokers (OR 1.14, 95% CI 0.93-1.40). Somewhat stronger associations emerged with heavy drinking in cardia (OR 1.61, 95% CI 1.11-2.34) than in non-cardia (OR 1.28, 95% CI 1.13-1.45) gastric cancers, and in intestinal-type (OR 1.54, 95% CI 1.20-1.97) than in diffuse-type (OR 1.29, 95% CI 1.05-1.58) cancers. The association was similar in strata of H. pylori infected (OR = 1.52, 95% CI 1.16-2.00) and noninfected subjects (OR = 1.69, 95% CI 0.95-3.01). Our collaborative pooled-analysis provides definite, more precise quantitative evidence than previously available of an association between heavy alcohol drinking and gastric cancer risk.

Primary enucleation for group D retinoblastoma in the era of systemic and targeted chemotherapy: the price of retaining an eye

BACKGROUND

Chemotherapy is increasingly used as primary treatment for group D retinoblastoma, whereas primary enucleation is considered to have a diminishing role. This study aimed to compare the management course, including number of examinations under anaesthesia (EUAs), of group D patients treated by enucleation versus chemotherapy.

METHODS

A retrospective analysis of 92 group D patients, of which 40 (37 unilateral) underwent primary enucleation and 52 (17 unilateral) were treated with intravenous chemotherapy. Number of EUAs was compared between the treatment groups with respect to the whole cohort, using univariate and multivariate analysis, and to unilateral cases only.

RESULTS

Patients were followed up for a median of 61 months (mean: 66, range: 14-156), in which time primary enucleated patients had on average seven EUAs and chemotherapy-treated patients 21 EUAs (p<0.001). Chemotherapy, young age, bilateral disease, multifocal tumours, familial and germline retinoblastoma were found on univariate analysis to correlate with increased number of EUAs (p≤0.019). On multivariate analysis, however, only treatment type and presentation age were found significant (p≤0.001). On subanalysis of the unilateral cases, patients undergoing primary enucleation had in average seven EUAs, as compared with 16 in the chemotherapy group (p<0.001). Of the 55 unilateral-presenting patients, a new tumour developed in the fellow eye only in a single familial case.

CONCLUSION

Group D patients' families should be counselled regarding the significant difference in number of EUAs following primary enucleation versus chemotherapy when deciding on a treatment strategy. In this regard, primary enucleation would be most beneficial for older patients with unilateral disease.

Maternal exposure to ambient air pollution and risk of early childhood cancers: A population-based study in Ontario, Canada

BACKGROUND

There are increasing concerns regarding the role of exposure to ambient air pollution during pregnancy in the development of early childhood cancers.

OBJECTIVE

This population based study examined whether prenatal and early life (<1year of age) exposures to ambient air pollutants, including nitrogen dioxide (NO₂) and particulate matter with aerodynamic diameters ≤2.5μm (PM_2.5), were associated with selected common early childhood cancers in Canada.

METHODS

2,350,898 singleton live births occurring between 1988 and 2012 were identified in the province of Ontario, Canada. We assigned temporally varying satellite-derived estimates of PM_2.5 and land-use regression model estimates of NO₂ to maternal residences during pregnancy. Incident cases of 13 subtypes of pediatric cancers among children up to age 6 until 2013 were ascertained through administrative health data linkages. Associations of trimester-specific, overall pregnancy and first year of life exposures were evaluated using Cox proportional hazards models, adjusting for potential confounders.

RESULTS

A total of 2044 childhood cancers were identified. Exposure to PM_2.5, per interquartile range increase, over the entire pregnancy, and during the first trimester was associated with an increased risk of astrocytoma (hazard ratio (HR) per 3.9μg/m3=1.38 (95% CI: 1.01, 1.88) and, HR per 4.0μg/m³=1.40 (95% CI: 1.05-1.86), respectively). We also found a positive association between first trimester NO₂ and acute lymphoblastic leukemia (ALL) (HR=1.20 (95% CI: 1.02-1.41) per IQR (13.3ppb)).

CONCLUSIONS

In this population-based study in the largest province of Canada, results suggest an association between exposure to ambient air pollution during pregnancy, especially in the first trimester and an increased risk of astrocytoma and ALL. Further studies are required to replicate the findings of this study with adjustment for important individual-level confounders.

International pooled study on diet and bladder cancer: the bladder cancer, epidemiology and nutritional determinants (BLEND) study: design and baseline characteristics

Background

In 2012, more than 400,000 urinary bladder cancer cases occurred worldwide, making it the 7^th most common type of cancer. Although many previous studies focused on the relationship between diet and bladder cancer, the evidence related to specific food items or nutrients that could be involved in the development of bladder cancer remains inconclusive. Dietary components can either be, or be activated into, potential carcinogens through metabolism, or act to prevent carcinogen damage.

Methods/design

The BLadder cancer, Epidemiology and Nutritional Determinants (BLEND) study was set up with the purpose of collecting individual patient data from observational studies on diet and bladder cancer. In total, data from 11,261 bladder cancer cases and 675,532 non-cases from 18 case–control and 6 cohort studies from all over the world were included with the aim to investigate the association between individual food items, nutrients and dietary patterns and risk of developing bladder cancer.

Discussion

The substantial number of cases included in this study will enable us to provide evidence with large statistical power, for dietary recommendations on the prevention of bladder cancer.

Dietary patterns and the risk of female breast cancer among participants of the Canadian National Enhanced Cancer Surveillance System

OBJECTIVES

The role of diet in the etiology of breast cancer is not well understood despite extensive research. In the majority of this work, a single nutrient-based approach has been used which does not take into account combinations of food that are consumed. An alternative to the single nutrient approach is to identify patterns in the dietary intake information and relate these patterns to disease incidence. This investigation characterized dietary patterns among participants of a Canadian case-control study and related these dietary patterns to the incidence of breast cancer.

METHODS

Dietary and other risk factor data from cases and controls of the Canadian National Enhanced Cancer Surveillance System were collected using self-administered questionnaires. Principal component factor analysis was used to classify individuals based on their dietary patterns. The relationship between these dietary patterns and breast cancer was evaluated using logistic regression. The derived odds ratios and their 95% confidence limits were adjusted for several factors, such as smoking, alcohol intake, environmental tobacco smoke exposure and obesity.

RESULTS

In the 2,009 cases and 2,086 controls, three dietary patterns were identified: western, healthy and vitamin. The highest quartile of the "healthy" dietary pattern was related to a 22% decrease in breast cancer risk (95% CI: 0.61-1.00), relative to the lowest quartile. The fourth quartile of the "vitamin" dietary pattern was associated with a 14% decrease in breast cancer risk (95% CI: 0.70-1.04) relative to the first. No statistically significant associations between the "western" dietary pattern and breast cancer were found. These associations were neither confounded nor modified by menopausal status.

CONCLUSION

Our analyses reveal that individual dietary items tend to cluster together in such a way that there are three distinct dietary patterns in this sample of Canadian women. Some of these patterns, in turn, were associated with the risk of breast cancer.

Occupational exposure to magnetic fields and breast cancer among Canadian men

Occupational magnetic field (MF) exposure has been suggested as a risk factor for breast cancer in both men and women. Due to the rarity of this disease in men, most epidemiologic studies investigating this relationship have been limited by small sample sizes. Herein, associations of several measures of occupational MF exposure with breast cancer in men were investigated using data from the population-based case-control component of the Canadian National Enhanced Cancer Surveillance System. Lifetime job histories were provided by 115 cases and 570 controls. Average MF exposure of individual jobs was classified into three categories (<0.3, 0.3 to <0.6, or ≥0.6 μT) through expert blinded review of participant's lifetime occupational histories. The impact of highest average and cumulative MF exposure, as well as exposure duration and specific exposure-time windows, on cancer risk was examined using logistic regression. The proportion of cases (25%) with a highest average exposure of ≥0.3 μT was higher than among controls (22%). We found an elevated risk of breast cancer in men who were exposed to ≥0.6 μT (odds ratio [OR] = 1.80, 95% CI = 0.82-3.95) when compared to those with exposures <0.3 μT. Those exposed to occupational MF fields for at least 30 years had a nearly threefold increase in risk of breast cancer (OR = 2.77, 95% CI = 0.98-7.82) when compared to those with background levels of exposure. Findings for the other time-related MF variables were inconsistent. Our analysis, in one of the largest case-control studies of breast cancer in men conducted to date, provides limited support for the hypothesis that exposure to MF increases the risk breast cancer in men.

Workplace exposure to diesel and gasoline engine exhausts and the risk of colorectal cancer in Canadian men

BACKGROUND

The International Agency for Research on Cancer (IARC) classified diesel exhaust as carcinogenic to humans (Group 1) and gasoline exhaust as a possible carcinogen (Group 2B) based studies of lung cancer, however the evidence for other sites is limited. We addressed this question by investigating exposure to diesel and gasoline emissions with respect to risk of colorectal cancer in men.

METHODS

We used data from a population-based case-control study with incident cases of colon (n = 931) and rectal (n = 840) cancer and 1360 controls from 7 Canadian provinces conducted in 1994-1997. Lifetime occupational history and information on other risk factors was collected. Occupational hygienists, blinded to case-control status, assigned exposures to each job for 3 dimensions: concentration, frequency, and reliability. Logistic regression was used to estimate odds ratios (OR) and their 95 % confidence intervals (CI), adjusted for age, province, use of proxy respondents, smoking, body-mass index, physical activity, intake of alcohol, processed meats, and occupational exposure to asbestos and aromatic amines.

RESULTS

Among CRC cases, 638 (36 %) were exposed to diesel and 814 (46 %) were exposed to gasoline emissions. Relative to the unexposed, elevated risks were observed among subjects ever exposed to high concentration levels of diesel emissions for colorectal cancer (OR = 1.65, 95 % CI = 0.98-2.80) and rectal cancer (OR = 1.98, 95 % CI = 1.09-3.60), but not colon cancer. Prolonged (>10 years) exposure at high concentrations was also associated with high risks of rectal cancer (OR = 2.33 95 % CI = 0.94-5.78; p-trend = 0.02). No statistically significant associations were observed for gasoline emissions.

CONCLUSIONS

Our findings suggest that sustained high-level exposure diesel emissions may increase the risk of rectal cancer.

Bladder cancer and occupational exposure to diesel and gasoline engine emissions among Canadian men

The International Agency for Research on Cancer has classified diesel exhaust as a carcinogen based on lung cancer evidence; however, few studies have investigated the effect of engine emissions on bladder cancer. The purpose of this study was to investigate the association between occupational exposure to diesel and gasoline emissions and bladder cancer in men using data from the Canadian National Enhanced Cancer Surveillance System; a population‐based case–control study. This analysis included 658 bladder cancer cases and 1360 controls with information on lifetime occupational histories and a large number of possible cancer risk factors. A job‐exposure matrix for engine emissions was supplemented by expert review to assign values for each job across three dimensions of exposure: concentration, frequency, and reliability. Odds ratios (OR) and their corresponding 95% confidence intervals were estimated using logistic regression. Relative to unexposed, men ever exposed to high concentrations of diesel emissions were at an increased risk of bladder cancer (OR = 1.64, 0.87–3.08), but this result was not significant, and those with >10 years of exposure to diesel emissions at high concentrations had a greater than twofold increase in risk (OR = 2.45, 1.04–5.74). Increased risk of bladder cancer was also observed with >30% of work time exposed to gasoline engine emissions (OR = 1.59, 1.04–2.43) relative to the unexposed, but only among men that had never been exposed to diesel emissions. Taken together, our findings support the hypothesis that exposure to high concentrations of diesel engine emissions may increase the risk of bladder cancer.

Exposure to ambient air pollution in Canada and the risk of adult leukemia

There is a paucity of studies investigating adult leukemia and air pollution. To address this gap, we analyzed data from a Canadian population-based case-control study conducted in 1994-1997. Cases were 1064 adults with incident leukemia and controls were 5039 healthy adults. We used data from satellites and fixed-site monitoring stations to estimate residential concentrations of NO2 and fine particulate matter (PM2.5) for the period prior to diagnosis, starting in 1975 and ending in 1994. We modeled the average annual exposure of each subject. Odds ratios (OR) and their 95% confidence intervals (CI) were estimated using logistic regression, adjusted for age, gender, province, smoking, education, body mass index, income, and self-reported exposures to ionizing radiation and benzene. We found an 'n-shaped' response function between exposure to NO2 and all forms of leukemia: from the tenth percentile to the median (4.51 to 14.66 ppb), the OR was 1.20; 95% CI: 0.97-1.48 and from the 75th percentile to the 90th (22.75 to 29.7 ppb), the OR was 0.79; 95% CI 0.68-0.93. For PM2.5 we found a response function consistent with a linear model, with an OR per 10 μg/m(3) of 0.97 (95% CI 0.75-1.26). For chronic lymphocytic leukemia we found response functions that were consistent with a simple linear model, with an OR per 5 ppb of NO2 of 0.93 (95% CI 0.86-1.00) and an OR per 10 μg/m(3) of PM2.5 of 0.62 (95% CI 0.42-0.93). In summary, for chronic lymphocytic leukemia we found no evidence of an association with air pollution and with all forms of leukemia we found weak evidence of an association only at low concentrations of NO2. It is possible that these inconsistent results may have arisen because of unaccounted urban/rural differences or possibly from a selection effect, especially among controls.

Status Report--Retracing the history of the early development of national chronic disease surveillance in Canada and the major role of the Laboratory Centre for Disease Control (LCDC) from 1972 to 2000

Health surveillance is the ongoing, systematic use of routinely collected health data to guide public health action in a timely fashion. This paper describes the creation and growth of national surveillance systems in Canada and their impact on chronic disease and injury prevention. In 2008, the authors started a review process to retrace the history of the early development of national chronic disease surveillance in Canada from 1960 to 2000. A 1967 publication describes the history of the development of the Laboratory of Hygiene from 1921 to 1967. This review is a sequel to that paper and describes the history of the development of national chronic disease surveillance in Canada before and after the formation of the Laboratory Centre for Disease Control (LCDC).

Nodal line-scanning method for maskless optical lithography

Maskless optical lithography can improve the economics and performance of multi-patterning by eliminating photomasks and by simplifying the lithography exposure technology. It could also potentially eliminate the need for multi-patterning by enabling dual-wavelength, nonlinear optical recording methods. High-resolution, maskless patterning can be achieved with a scanned-spot-array system in which modulated, diffraction-limited focus spots write the exposure pattern. Each spot has a central zero-intensity interference null along a line parallel to the scan direction for printing sub-resolution line patterns. High throughput can be achieved at the comparatively low repetition rate of excimer lasers (e.g., 6 kHz). The low repetition rate simplifies the optical modulation technology, enabling the use of supplemental modulation controls including dynamic gray-level and beam-centration controls for resolution enhancement.

Effect of web-based messages on girls' knowledge and risk perceptions related to cigarette smoke and breast cancer: 6-month follow-up of a randomized controlled trial

Background

Evidence indicating an association between cigarette smoke exposure and an increase in breast cancer risk highlights the need for health messages that aim to prevent smoking initiation and reduce secondhand smoke (SHS) exposure among adolescent girls.

Objective

This study aimed to evaluate the efficacy of targeted gender-sensitive, breast cancer-specific, Web-based messages about the increased risk of breast cancer associated with cigarette smoke exposure. Outcomes assessed 6 months postmessage delivery included nonsmoking adolescent girls’ knowledge of the link between cigarette smoke exposure and breast cancer, perceptions of breast cancer risk associated with cigarette smoke, smoking behavior and intentions, and stage of change related to avoidance of secondhand smoke.

Methods

A prospective randomized controlled trial was used to compare standard (control) messages with targeted gender- and Aboriginal status-sensitive, breast cancer-specific (intervention) messages. Messages were delivered online to 618 nonsmoking girls, aged 13 to 15 years, clustered in 74 Canadian secondary schools.

Results

Compared with the control group, girls in the intervention group were significantly more likely to report that breast cancer is an illness caused by cigarette smoke (adjusted relative risk [ARR] 1.33, 95% CI 1.05-1.68) and to agree that exposure to SHS increases their risk of breast cancer (ARR 1.10, 95% CI 1.02-1.20). No significant effects were observed for a change in smoking status, intention to try smoking, or stage of change related to avoidance of SHS.

Conclusions

Compared with standard messages, targeted gender-sensitive, breast cancer-specific messages had a stronger influence on girls’ knowledge and perceived risk of cigarette smoke exposure as a risk factor for breast cancer. Brief information-based interventions delivered over the Internet have the potential to provide effective health promotion that could be broadly disseminated and lead to long-term effects on girls’ knowledge and risk perceptions about cigarette exposure and breast cancer.

Projection operator method for biperiodic diffraction gratings with anisotropic/bianisotropic generalizations

The "projection operator" method is a variation of the normal-vector method for simulating optical diffraction from biperiodic gratings. A projection operator defined by the normal vector is interpolated over the grating volume rather than interpolating the vector itself. This approach circumvents difficulties associated with sign reversals and discontinuities encountered with the normal-vector method, and it facilitates implementation for general grating geometries. The method is readily extensible to anisotropic and bianisotropic materials. Several numerical examples of the new method are presented, including comparisons to previously published test cases.

Anthropometric and hormonal risk factors for male breast cancer: male breast cancer pooling project results

BACKGROUND

The etiology of male breast cancer is poorly understood, partly because of its relative rarity. Although genetic factors are involved, less is known regarding the role of anthropometric and hormonally related risk factors.

METHODS

In the Male Breast Cancer Pooling Project, a consortium of 11 case-control and 10 cohort investigations involving 2405 case patients (n = 1190 from case-control and n = 1215 from cohort studies) and 52013 control subjects, individual participant data were harmonized and pooled. Unconditional logistic regression generated study design-specific (case-control/cohort) odds ratios (ORs) and 95% confidence intervals (CIs), with exposure estimates combined using fixed effects meta-analysis. All statistical tests were two-sided.

RESULTS

Risk was statistically significantly associated with weight (highest/lowest tertile: OR = 1.36; 95% CI = 1.18 to 1.57), height (OR = 1.18; 95% CI = 1.01 to 1.38), and body mass index (BMI; OR = 1.30; 95% CI = 1.12 to 1.51), with evidence that recent rather than distant BMI was the strongest predictor. Klinefelter syndrome (OR = 24.7; 95% CI = 8.94 to 68.4) and gynecomastia (OR = 9.78; 95% CI = 7.52 to 12.7) were also statistically significantly associated with risk, relations that were independent of BMI. Diabetes also emerged as an independent risk factor (OR = 1.19; 95% CI = 1.04 to 1.37). There were also suggestive relations with cryptorchidism (OR = 2.18; 95% CI = 0.96 to 4.94) and orchitis (OR = 1.43; 95% CI = 1.02 to 1.99). Although age at onset of puberty and histories of infertility were unrelated to risk, never having had children was statistically significantly related (OR = 1.29; 95% CI = 1.01 to 1.66). Among individuals diagnosed at older ages, a history of fractures was statistically significantly related (OR = 1.41; 95% CI = 1.07 to 1.86).

CONCLUSIONS

Consistent findings across case-control and cohort investigations, complemented by pooled analyses, indicated important roles for anthropometric and hormonal risk factors in the etiology of male breast cancer. Further investigation should focus on potential roles of endogenous hormones.

Geographic variation in radon and associated lung cancer risk in Canada

OBJECTIVE

Radon is an important risk factor for lung cancer. Here we use maps of the geographic variation in radon to estimate the lung cancer risk associated with living in high radon areas of Canada.

METHODS

Geographic variation in radon was estimated using two mapping methods. The first used a Health Canada survey of 14,000 residential radon measurements aggregated to health regions, and the second, radon risk areas previously estimated from geology, sediment geochemistry and aerial gamma-ray spectrometry. Lung cancer risk associated with living in these radon areas was examined using a population-based case-control study of 2,390 lung cancer cases and 3,507 controls collected from 1994-1997 in eight Canadian provinces. Residential histories over a 20-year period were used in combination with the two mapping methods to estimate ecological radon exposures. Hierarchical logistic regression analyses were used to estimate odds ratios for lung cancer incidence, after adjusting for a comprehensive set of individual and geographic covariates.

RESULTS

Across health regions in Canada, significant variation in average residential radon concentrations (range: 16-386 Bq/m3) and in high geological-based radon areas (range: 0-100%) is present. In multivariate models, a 50 Bq/m3 increase in average health region radon was associated with a 7% (95% CI: -6-21%) increase in the odds of lung cancer. For every 10 years that individuals lived in high radon geological areas, the odds of lung cancer increased by 11% (95% CI: 1-23%).

CONCLUSIONS

These findings provide further evidence that radon is an important risk factor for lung cancer and that risks are unevenly distributed across Canada.

Abstract P1-13-02: Benefit/risk of invasive breast cancer adjuvant tamoxifen or aromatase inhibitor use by age, race/ethnicity, and co-morbidity

Background: Older age, minority race/ethnicity, and co-morbidities adversely influence early stage IBC outcome. Further, as AI compared to tamoxifen use has different effects on IBC recurrence and other health outcomes including hip fracture, endometrial cancer, stroke, pulmonary embolism and, perhaps especially, coronary heart disease (CHD), an approach to summarize relative benefit/risk of these agents is needed.

Methods: Incidence rates for health outcomes by age and race/ethnicity, absent AI or tamoxifen use, were obtained from the placebo arms of the three primary Women's Health Initiative clinical prevention trials (n = 33,072). AI and tamoxifen effects on IBC distant recurrence (relative risk [PR] 0.82) were estimated from a meta-analysis of the ATAC and Big-1-98 trial results (n = 14,149) and on other health outcomes from published meta-analysis of side effects in seven AI vs tamoxifen trials (n = 30,023); RR of 1.47 for hip fracture, 0.34 for endometrial cancer, 0.84 for stroke, 0.55 for pulmonary embolism, 1.26 for CHD (Amir et al JNCI 2011;103:1299). Following the methodology of Freedman et al (JCO 2011;29:2327), mortality weights were assigned health outcomes (5 year mortality risk of 0.2 for MI, 0.8 for IBC distant recurrence, etc) to assess net all cause mortality benefit/risk for AI compared to tamoxifen by recurrence risk, age (decade), race/ethnicity, hysterectomy (yes/no) and, in separate analyses, in women with diabetes and in women with cardiovascular disease [CVD] history.

Results: In these analyses, clinical outcome of women with early stage IBC was unfavorable (more deaths per 1000 women/years) with tamoxifen compared to AI adjuvant use regardless of age, race/ethnicity, diabetes or CVD history even with 10-year distant recurrence risk of only 10%. AI superiority was substantially greater in women with a uterus and, in exploratory analyses, when assuming a CVD relative risk for AI use of 1.0, rather than a CHD relative risk of 1.26 used in all other analyses, as the AI CHDrisk elevation is controversial. The net benefit of AI compared to tamoxifen influence on clinical outcomes are described in a series of tables to be presented which quantify benefit/risk in particular women groups. The example below illustrates the excess number of deaths/1000 woman years for tamoxifen vs. AI by recurrence risk, age, and hysterectomy status.

 Excess Number of Deaths per 1000 women/year for Tamoxifen Compared to AI Tamoxifen vs. AI (with uterus)Tamoxifen vs. AI (without uterus)10-year Distant Recurrence (%)Age GroupAge Group 50-59y60-69y70-79y50-59y60-69y70-79y1015120620010211111030326382375278287286

For a 60-69 year old woman with a uterus at 30% 10 year recurrence risk, there would be 382 more deaths per 1000 women/yr for tamoxifen vs. AI use. With prior hysterectomy, there would still be 287 more deaths for tamoxifen use.

Conclusion: We developed an index to quantify the benefit risk for adjuvant AI vs. tamoxifen use. Even assessing a RR of 1.26 for CHD for AI use, tamoxifen compared to AI use had unfavorable outcome in all examined groups. This index can complement clinical evaluation in comparing use of these two adjuvant therapy approaches in women of different ages and racial/ethnic groups.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-13-02.

Initial impact of tailored web-based messages about cigarette smoke and breast cancer risk on boys' and girls' risk perceptions and information seeking: randomized controlled trial

Background

Recent evidence indicates a causal link between both active smoking and secondhand smoke (SHS) exposure and breast cancer (BC).

Objective

The objective of the present study was to evaluate the initial reactions of girls and boys to tailored Web-based messages that describe the relationship between SHS and BC, using a parallel, single-blinded cluster randomized controlled trial.

Methods

This trial was nested within a cycle of an ongoing longitudinal study of 1498 students from 74 secondary schools. Self-reported assessments were used to evaluate the impact of study messages on participants’ risk perception and interest in obtaining additional information after participants were randomized by schools to control or intervention groups. The intervention group received a tailored visual message (based on gender and Aboriginal status) about BC and tobacco smoke. The control group received a standard visual message about smoking and cancer.

Results

SHS exposure was identified as a BC risk factor by 380/1488 (25.54%) participants, during the preintervention analysis. Compared to the female participants in the control group (491/839, 58.5%), girls who received the intervention (339/649, 52.2%) were 14% more likely to agree that exposure to SHS increased their BC risk (relative risk [RR] 1.14, 95% CI 1.07-1.21). Nonsmoking girls who received the intervention were 14% more likely to agree that starting smoking would increase their BC risk (RR 1.14, 95% CI 1.07-1.21). Compared to the male participants in control group (348/839, 41.5%), boys who received the intervention (310/649, 47.8%) were 10% more likely to agree that girls’ exposure to SHS increased their BC risk (RR 1.10, 95% CI 1.02-1.18). Compared to controls, girls who received the intervention were 52% more likely to request additional information about SHS and BC (RR 1.52, 95% CI 1.12-2.06).

Conclusions

Brief gender-sensitive messages delivered via the Internet have the potential to increase awareness and to stimulate information seeking about the risk for BC associated with SHS.

Occupational exposure to crystalline silica and the risk of lung cancer in Canadian men

Crystalline silica is a recognized carcinogen, but the association with lung cancer at lower levels of exposure has not been well characterized. This study investigated the relationship between occupational silica exposure and lung cancer and the combined effects of cigarette smoking and silica exposure on lung cancer risk. A population-based case-control study was conducted in eight Canadian provinces between 1994 and 1997. Self-reported questionnaires were used to obtain a lifetime occupational history and information on other risk factors. Occupational hygienists assigned silica exposures to each job based on concentration, frequency and reliability. Data from 1681 incident lung cancer cases and 2053 controls were analyzed using logistic regression to estimate odds ratios (OR) and their 95% confidence intervals (CI). Models included adjustments for cigarette smoking, lifetime residential second-hand smoke and occupational exposure to diesel and gasoline engine emissions. Relative to the unexposed, increasing duration of silica exposure at any concentration was associated with a significant trend in lung cancer risk (OR ≥ 30 years: 1.67, 1.21-2.24; ptrend  = 0.002). The highest tertile of cumulative silica exposure was associated with lung cancer (OR = 1.81, 1.34-2.42; ptrend  = 0.004) relative to the lowest. Men exposed to silica for ≥30 years with ≥40 cigarette pack-years had the highest risk relative to those unexposed with <10 pack-years (OR = 42.53, 23.54-76.83). The joint relationship with smoking was consistent with a multiplicative model. Our findings suggest that occupational exposure to silica is a risk factor for lung cancer, independently from active and passive smoking, as well as from exposure to other lung carcinogens.

Generalization of adiposity genetic loci to US Hispanic women

BACKGROUND:

Obesity is a public health concern. Yet the identification of adiposity-related genetic variants among United States (US) Hispanics, which is the largest US minority group, remains largely unknown.

OBJECTIVE:

To interrogate an a priori list of 47 (32 overall body mass and 15 central adiposity) index single-nucleotide polymorphisms (SNPs) previously studied in individuals of European descent among 3494 US Hispanic women in the Women's Health Initiative SNP Health Association Resource (WHI SHARe).

DESIGN:

Cross-sectional analysis of measured body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) were inverse normally transformed after adjusting for age, smoking, center and global ancestry. WC and WHR models were also adjusted for BMI. Genotyping was performed using the Affymetrix 6.0 array. In the absence of an a priori selected SNP, a proxy was selected (r²⩾0.8 in CEU).

RESULTS:

Six BMI loci (TMEM18, NUDT3/HMGA1, FAIM2, FTO, MC4R and KCTD15) and two WC/WHR loci (VEGFA and ITPR2-SSPN) were nominally significant (P<0.05) at the index or proxy SNP in the corresponding BMI and WC/WHR models. To account for distinct linkage disequilibrium patterns in Hispanics and further assess generalization of genetic effects at each locus, we interrogated the evidence for association at the 47 surrounding loci within 1 Mb region of the index or proxy SNP. Three additional BMI loci (FANCL, TFAP2B and ETV5) and five WC/WHR loci (DNM3-PIGC, GRB14, ADAMTS9, LY86 and MSRA) displayed Bonferroni-corrected significant associations with BMI and WC/WHR. Conditional analyses of each index SNP (or its proxy) and the most significant SNP within the 1 Mb region supported the possible presence of index-independent signals at each of these eight loci as well as at KCTD15.

CONCLUSION:

This study provides evidence for the generalization of nine BMI and seven central adiposity loci in Hispanic women. This study expands the current knowledge of common adiposity-related genetic loci to Hispanic women.

Breast cancer detection and survival among women with cosmetic breast implants: systematic review and meta-analysis of observational studies

OBJECTIVES

To evaluate whether the stage distribution among women diagnosed as having breast cancer differs between those who have received breast implants for cosmetic purposes and those with no implants and to evaluate whether cosmetic breast augmentation before the detection of breast cancer is a predictor of post-diagnosis survival.

DESIGN

Systematic review of observational studies with two meta-analyses.

DATA SOURCES

Systematic search of the literature published before September 2012 conducted in Medline, Embase, Global health, CINAHL, IPAB, and PsycINFO.

STUDY SELECTION

Eligible publications were those that included women diagnosed as having breast cancer and who had had augmentation mammaplasty for cosmetic purposes.

RESULTS

The overall odds ratio of the first meta-analysis based on 12 studies was 1.26 (95% confidence interval 0.99 to 1.60; P=0.058; I(2)=35.6%) for a non-localized stage of breast cancer at diagnosis comparing women with implants who had breast cancer and women without implants who had breast cancer. The second meta-analysis, based on five studies, evaluated the relation between cosmetic breast implantation and survival. This meta-analysis showed reduced survival after breast cancer among women who had implants compared with those who did not (overall hazard ratio for breast cancer specific mortality 1.38, 95% confidence interval 1.08 to 1.75).

CONCLUSIONS

The research published to date suggests that cosmetic breast augmentation adversely affects the survival of women who are subsequently diagnosed as having breast cancer. These findings should be interpreted with caution, as some studies included in the meta-analysis on survival did not adjust for potential confounders. Further investigations are warranted regarding diagnosis and prognosis of breast cancer among women with breast implants.

Occupational exposure to asbestos and lung cancer in men: evidence from a population-based case-control study in eight Canadian provinces

Background

Asbestos is classified as a human carcinogen, and studies have consistently demonstrated that workplace exposure to it increases the risk of developing lung cancer. Few studies have evaluated risks in population-based settings where there is a greater variety in the types of occupations, and exposures.

Methods

This was a population based case–control study with 1,681 incident cases of lung cancer, and 2,053 controls recruited from 8 Canadian provinces between 1994 and 1997. Self-reported questionnaires were used to elicit a lifetime occupational history, including general tasks, and information for other risk factors. Occupational hygienists, who were blinded to case–control status, assigned asbestos exposures to each job on the basis of (i) concentration (low, medium, high), (ii) frequency (<5%, 5-30%, and >30% of the time in a normal work week), and (iii) reliability (possible, probable, definite). Logistic regression was used to estimate odds ratios (ORs) and their corresponding 95% confidence intervals (CI).

Results

Those occupationally exposed to (i) low, and (ii) medium or high concentrations of asbestos had ORs for lung cancer of 1.17 (95% CI=0.92 – 1.50) and 2.16 (95% CI=1.21-3.88), respectively, relative to those who were unexposed. Medium or high exposure to asbestos roughly doubled the risk for lung cancer across all three smoking pack-year categories. The joint relationship between smoking and asbestos was consistent with a multiplicative risk model.

Conclusions

Our findings provide further evidence that exposure to asbestos has contributed to an increased risk of lung cancer in Canadian workplaces, and suggests that nearly 3% of lung cancers among Canadian men are caused by occupational exposure to asbestos.

Spatiotemporal air pollution exposure assessment for a Canadian population-based lung cancer case-control study

BACKGROUND

Few epidemiological studies of air pollution have used residential histories to develop long-term retrospective exposure estimates for multiple ambient air pollutants and vehicle and industrial emissions. We present such an exposure assessment for a Canadian population-based lung cancer case-control study of 8353 individuals using self-reported residential histories from 1975 to 1994. We also examine the implications of disregarding and/or improperly accounting for residential mobility in long-term exposure assessments.

METHODS

National spatial surfaces of ambient air pollution were compiled from recent satellite-based estimates (for PM2.5 and NO2) and a chemical transport model (for O3). The surfaces were adjusted with historical annual air pollution monitoring data, using either spatiotemporal interpolation or linear regression. Model evaluation was conducted using an independent ten percent subset of monitoring data per year. Proximity to major roads, incorporating a temporal weighting factor based on Canadian mobile-source emission estimates, was used to estimate exposure to vehicle emissions. A comprehensive inventory of geocoded industries was used to estimate proximity to major and minor industrial emissions.

RESULTS

Calibration of the national PM2.5 surface using annual spatiotemporal interpolation predicted historical PM2.5 measurement data best (R2 = 0.51), while linear regression incorporating the national surfaces, a time-trend and population density best predicted historical concentrations of NO2 (R2 = 0.38) and O3 (R2 = 0.56). Applying the models to study participants residential histories between 1975 and 1994 resulted in mean PM2.5, NO2 and O3 exposures of 11.3 μg/m3 (SD = 2.6), 17.7 ppb (4.1), and 26.4 ppb (3.4) respectively. On average, individuals lived within 300 m of a highway for 2.9 years (15% of exposure-years) and within 3 km of a major industrial emitter for 6.4 years (32% of exposure-years). Approximately 50% of individuals were classified into a different PM2.5, NO2 and O3 exposure quintile when using study entry postal codes and spatial pollution surfaces, in comparison to exposures derived from residential histories and spatiotemporal air pollution models. Recall bias was also present for self-reported residential histories prior to 1975, with cases recalling older residences more often than controls.

CONCLUSIONS

We demonstrate a flexible exposure assessment approach for estimating historical air pollution concentrations over large geographical areas and time-periods. In addition, we highlight the importance of including residential histories in long-term exposure assessments. For submission to: Environmental Health.

Occupational exposure to diesel and gasoline emissions and lung cancer in Canadian men

The International Agency for Research on Cancer classifies diesel exhaust as a probable human carcinogen; this decision is based largely from lung cancer evidence. Gasoline exhaust is classified as a possible carcinogen. Epidemiological studies are needed that improve upon some of the limitations of previous research with respect to the characterization of exposure, and the control for the potential confounding influence of smoking and other occupational exposures. Our objective was to investigate associations between occupational exposure to diesel and gasoline engine emissions and lung cancer. We used a case-control study design that involved men 40 years of age and older at the time of interview. Analyses are based on 1681 incident cases of lung cancer and 2,053 population controls. A self-reported questionnaire elicited a lifetime occupational history, including general tasks, and information on other potential risk factors. Occupational exposures to diesel and gasoline emissions, crystalline silica, and asbestos were assigned to each job held by study subjects by industrial hygienists who were blind to case-control status. Exposure metrics for diesel and gasoline emissions that were modeled included: ever exposure, cumulative exposure, and concentration of exposure. We found a dose-response relationship between cumulative occupational exposure to diesel engine emissions and lung cancer. This association was more pronounced for the squamous and large cell subtypes with adjusted odds ratios across the three increasing tertiles of cumulative lifetime exposure relative to those with no exposure of 0.99, 1.25, and 1.32 (p=0.04) for squamous cell carcinoma, and 1.06, 1.19, 1.68 (p=0.02) for large cell carcinoma. While the association with cumulative exposure to gasoline was weakly positive, it was not statistically significant. Our findings suggest that exposure to diesel engine emissions increases the risk of lung cancer particularly for squamous and large cell carcinoma subtypes.

Active smoking and secondhand smoke increase breast cancer risk: the report of the Canadian Expert Panel on Tobacco Smoke and Breast Cancer Risk (2009)

Four authoritative reviews of active smoking and breast cancer have been published since 2000, but only one considered data after 2002 and conclusions varied. Three reviews of secondhand smoke (SHS) and breast cancer (2004-2006) each came to different conclusions. With 30 new studies since 2002, further review was deemed desirable. An Expert Panel was convened by four Canadian agencies, the Ontario Tobacco Research Unit, the Public Health Agency of Canada, Physicians for a Smoke-Free Canada and the Canadian Partnership Against Cancer to comprehensively examine the weight of evidence from epidemiological and toxicological studies and understanding of biological mechanisms regarding the relationship between tobacco smoke and breast cancer. This article summarises the panel's full report (http://www.otru.org/pdf/special/expert_panel_tobacco_breast_cancer.pdf). There are 20 known or suspected mammary carcinogens in tobacco smoke, and recognised biological mechanisms that explain how exposure to these carcinogens could lead to breast cancer. Results from the nine cohort studies reporting exposure metrics more detailed than ever/never and ex/current smoker show that early age of smoking commencement, higher pack-years and longer duration of smoking increase breast cancer risk 15% to 40%. Three meta-analyses report 35% to 50% increases in breast cancer risk for long-term smokers with N-acetyltransferase 2 gene (NAT2) slow acetylation genotypes. The active smoking evidence bolsters support for three meta-analyses that each reported about a 65% increase in premenopausal breast cancer risk among never smokers exposed to SHS. The Panel concluded that: 1) the association between active smoking and breast cancer is consistent with causality and 2) the association between SHS and breast cancer among younger, primarily premenopausal women who have never smoked is consistent with causality.

Young women's responses to smoking and breast cancer risk information

Current evidence confirms that young women who smoke or who have regular long-term exposure to secondhand smoke (SHS) have an increased risk of developing premenopausal breast cancer. The aim of this research was to examine the responses of young women to health information about the links between active smoking and SHS exposure and breast cancer and obtain their advice about messaging approaches. Data were collected in focus groups with 46 women, divided in three age cohorts: 15-17, 18-19 and 20-24 and organized according to smoking status (smoking, non-smoking and mixed smoking status groups). The discussion questions were preceded by information about passive and active smoking and its associated breast cancer risk. The study findings show young women's interest in this risk factor for breast cancer. Three themes were drawn from the analysis: making sense of the information on smoking and breast cancer, personal susceptibility and tobacco exposure and suggestions for increasing awareness about tobacco exposure and breast cancer. There was general consensus on framing public awareness messages about this risk factor on 'protecting others' from breast cancer to catch smokers' attention, providing young women with the facts and personal stories of breast cancer to help establish a personal connection with this information and overcome desensitization related to tobacco messages, and targeting all smokers who may place young women at risk. Cautions were also raised about the potential for stigmatization. Implications for raising awareness about this modifiable risk factor for breast cancer are discussed.