Showing papers by "Susan J. Bondy published in 2020"

Iron intake, oxidative stress‐related genes and breast cancer risk

Abstract: Iron has been suggested to contribute to breast cancer development through oxidative stress generation. Our study investigated associations between iron intake and breast cancer risk, overall and by menopausal and estrogen receptor/progesterone receptor (ER/PR) status, and modification by oxidative stress-related genetic polymorphisms (MnSOD, GSTM1 and GSTT1). A population-based case-control study (3,030 cases and 3,402 controls) was conducted in Ontario, Canada. Iron intake (total, dietary, supplemental, heme, nonheme) was assessed using a validated food frequency questionnaire. Odds ratios (OR) and 95% confidence intervals (CI) were estimated from multivariable logistic regression models. Interactions between iron intake and genotypes were assessed among 1,696 cases and 1,761 controls providing DNA. Overall, no associations were observed between iron intake and breast cancer risk. Among premenopausal women, total, dietary and dietary nonheme iron were positively associated with ER-/PR- breast cancer risk (all ptrend 18 vs. 0 mg/day = 0.68, 95% CI: 0.51-0.91), and dietary heme iron was associated with an increased risk, particularly the ER-/PR- subtype (ORhighest vs. lowest quintile = 1.69, 95% CI: 1.16-2.47; ptrend = 0.02). Furthermore, GSTT1 and combined GSTM1/GSTT1 polymorphisms modified some of the associations. For example, higher dietary iron was most strongly associated with increased breast cancer risk among women with GSTT1 deletion or GSTM1/GSTT1 double deletions (pinteraction < 0.05). Findings suggest that iron intake may have different effects on breast cancer risk according to menopausal and hormone receptor status, as well as genotypes affecting antioxidant capacity.

Real-World Effectiveness of Pharmaceutical Smoking Cessation Aids: Time-Varying Effects.

Abstract: Background There are a limited number of studies that have examined the real-world effectiveness of smoking cessation aids and relapse longitudinally in population-representative samples. This study examines the association between use of nicotine gum, patch, bupropion, and varenicline and time to relapse as well as any changes in the association with increased length of abstinence. Methods Data of 1821 current adult smokers (18+) making their first serious quit attempt were compiled from 4504 individuals enrolled in the Ontario Tobacco Survey, a representative telephone survey of Ontario adults, which followed smokers every 6 months for up to 3 years. Use of cessation aids at the time of initial report of a quit attempt was analyzed. A flexible parametric survival model was developed to model length of abstinence, controlling for potential confounders. Results The best fit model found knots at 3, 13, 43, and 212 days abstinent, suggesting different rates of relapse in the periods marked by those days. Use of the patch and varenicline was associated with lower rates of relapse, but no positive effect was found for bupropion or nicotine gum. The effectiveness of the patch reversed in effect after the first month of abstinence. Conclusions This study is one of few reports of long-term quitting in a population-representative sample and demonstrates that the effectiveness of some pharmacological cessation aids (the patch and varenicline can be seen in a population sample). Previous failures in real-world studies of the effectiveness of smoking cessation aids may reflect differences in the products individuals use and differences in the timing of self-reported cessation. Implications While a large number of randomized controlled trials have shown the efficacy of many pharmaceutical smoking cessation aids, evidence of their effectiveness in observational studies in the real world is ambiguous. This study uses a longitudinal cohort of a representative sample of smokers to show that the effectiveness of pharmaceutical cessation aids can be demonstrated in real-world use situations, but effectiveness varies by product type and has time-varying effects.

Variability in patient sociodemographics, clinical characteristics, and healthcare service utilization among 107,302 treatment seeking smokers in Ontario: A cross-sectional comparison.

Abstract: Background: Since 2005, the Smoking Treatment for Ontario Patients (STOP) program has provided smoking cessation treatment of varying form and intensity to smokers through 11 distinct treatment models, either in-person at partnering healthcare organizations or remotely via web or telephone. We aimed to characterize the patient populations reached by different treatment models.Methods: We linked self-report data to health administrative databases to describe sociodemographics, physical and mental health comorbidity, healthcare utilization and costs. Our sample consisted of 107,302 patients who enrolled between 18Oct2005 and 31Mar2016, across 11 models operational during different time periods.Results: Patient populations varied on sociodemographics, comorbidity burden, and healthcare usage. Enrollees in the Web-based model were youngest (median age: 39; IQR: 29-49), and enrollees in primary care-based Family Health Teams were oldest (median: 51; IQR: 40-60). Chronic Obstructive Pulmonary Disease and hypertension were the most common physical health comorbidities, twice as prevalent in Family Health Teams (32.3% and 30.8%) than in the direct-to-smoker (Web and Telephone) and Pharmacy models (13.5%-16.7% and 14.7%-17.7%). Depression, the most prevalent mental health diagnosis, was twice as prevalent in the Addiction Agency (52.1%) versus the Telephone model (25.3%). Median healthcare costs in the two years up to enrollment ranged from $1,787 in the Telephone model to $9,393 in the Addiction Agency model.Discussion: While practitioner-mediated models in specialized and primary care settings reached smokers with more complex healthcare needs, alternative settings appear better suited to reach younger smokers before such comorbidities develop. Although Web and Telephone models were expected to have fewer barriers to access, they reached a lower proportion of patients in rural areas and of lower socioeconomic status. Findings suggest that in addition to population-based strategies, embedding smoking cessation treatment into existing healthcare settings that reach patient populations with varying disparities may enhance equitable access to treatment.

Exposure to maternal depressive symptoms in childhood and adolescent suicide-related thoughts and attempts: mediation by child psychiatric symptoms

Abstract: Aims The nature of the association between child psychiatric symptoms and adolescent suicide-related thoughts (SRT) and attempts (SA) remains unclear. Our objective was to assess whether child psychiatric symptoms from 6 to 10 years of age mediate the association between exposure to maternal depressive symptoms in childhood and offspring SRT and SA in adolescence. Methods A population-based cohort study was constructed by linking all eight cycles from the National Longitudinal Survey of Children and Youth (NLSCY), a nationally representative Canadian panel survey conducted from 1994 to 2009. Self-reported maternal depressive symptoms were measured when offspring were between 0 and 5 years. Maternal-reported child psychiatric symptoms and psychiatric comorbid symptoms were measured from 6 to 10 years, and offspring self-reported SRT and SA were measured between 11 and 19 years. Indirect effects, the effect proportion mediated and their corresponding bootstrapped 95% confidence intervals (CI) were estimated. Results Hyperactivity and inattention significantly mediated the association between maternal depressive symptoms in childhood and risk of both SRT and SA from 11 to 19 years, where approximately 60% (SRT 95% CI 23-94%; SA 95% CI 27-95%) of this association was explained by hyperactivity and inattention. Psychiatric comorbid symptoms also significantly mediated this relationship and accounted for 50% (95% CI 18-81%) of this association with SA. Conclusions Targeting hyperactivity and inattention, and co-occurring psychiatric symptoms in offspring of depressed mothers could reduce risk of SRT, eventual SA and halt progression towards suicide. However, further understanding of comorbid psychiatric symptoms in childhood that most strongly predict adolescent SA is needed.