Age of smoking initiation and risk of breast cancer in a sample of Ontario women

<p>Abstract</p> <p>Objectives</p> <p>To examine the association between time of smoking initiation and both the independent and joint effects of active and passive tobacco smoke exposure and the risk of breast cancer in a sample of Ontario women.</p> <p>Methods</p> <p>Data from two large population-based case-control studies conducted among Ontario women aged 25–75 years were combined for analysis (n = 12,768).</p> <p>Results</p> <p>Women who had ever smoked and were exposed to passive smoke had a significant increased risk of breast cancer (OR 1.13, 95%CI 1.01–1.25). A significant increased risk was also observed among women who initiated smoking: at age 26 or older (OR 1.26, 95%CI 1.03–1.55); more than five years from menarche (OR 1.26, 95%CI 1.12–1.42); and, after their first live birth (OR 1.25, 95%CI 1.02–1.52).</p> <p>Conclusion</p> <p>The results suggest that women who initiate smoking at an older age are at an increased risk of breast cancer.</p

Randomized Controlled Trial of the Use of an Educational Cancer Website to Increase Cancer Patient’s Participation into a Research Study

[[abstract]]The present randomized controlled trial was conducted to determine if providing access to an educational colorectal cancer Website for patients with colorectal cancer might increase their subsequent participation in a population-based cancer study. A total of 384 potential participants recruited from colorectal cancer cases identified from the Ontario Cancer Registry and the Mount Sinai Hospital in Toronto, Ontario, Canada were randomly divided into two groups. The control group was mailed an invitation package containing a brochure describing a population-based cancer registry (the Ontario Familial Colorectal Cancer Registry, OFCCR), a family history questionnaire, and a colorectal cancer educational pamphlet. The intervention group was mailed the information for access to a colorectal cancer educational Website in addition to the materials sent to the control group. Results indicated that providing access information to an educational Website about colorectal cancer did not increase the participation of colorectal cancer patients in a population-based cancer study. The participation for the intervention group (66%) was not significantly different (p=0.38) from the control group (62%). The additional provision of a Website with colorectal cancer information to patients appears not to be an effective strategy to improve subsequent participation in a population-based cancer study

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%)

Osteoporosis-related fracture case definitions for population-based administrative data

<p>Abstract</p> <p>Background</p> <p>Population-based administrative data have been used to study osteoporosis-related fracture risk factors and outcomes, but there has been limited research about the validity of these data for ascertaining fracture cases. The objectives of this study were to: (a) compare fracture incidence estimates from administrative data with estimates from population-based clinically-validated data, and (b) test for differences in incidence estimates from multiple administrative data case definitions.</p> <p>Methods</p> <p>Thirty-five case definitions for incident fractures of the hip, wrist, humerus, and clinical vertebrae were constructed using diagnosis codes in hospital data and diagnosis and service codes in physician billing data from Manitoba, Canada. Clinically-validated fractures were identified from the Canadian Multicentre Osteoporosis Study (CaMos). Generalized linear models were used to test for differences in incidence estimates.</p> <p>Results</p> <p>For hip fracture, sex-specific differences were observed in the magnitude of under- and over-ascertainment of administrative data case definitions when compared with CaMos data. The length of the fracture-free period to ascertain incident cases had a variable effect on over-ascertainment across fracture sites, as did the use of imaging, fixation, or repair service codes. Case definitions based on hospital data resulted in under-ascertainment of incident clinical vertebral fractures. There were no significant differences in trend estimates for wrist, humerus, and clinical vertebral case definitions.</p> <p>Conclusions</p> <p>The validity of administrative data for estimating fracture incidence depends on the site and features of the case definition.</p

Helicobacter pylori infection in Ontario: Prevalence and risk factors

BACKGROUND: Helicobacter pylori has been classified by the World Health Organization as a type I carcinogen. Nearly 50% of the world’s population is estimated to be infected with H pylori. Prevalence patterns of the infection are different between developing and developed countries. The present study had two objectives – to estimate the prevalence of H pylori infection in Ontario, and to evaluate the relationship between the infection and various demographic characteristics and selected lifestyle factors

Rotating shift work associated with obesity in men from northeastern Ontario

Introduction: While some studies have suggested associations between shift work and obesity, few have been population-based or considered multiple shift schedules. Since obesity is linked with several chronic health conditions, understanding which types of shift work influence obesity is important and additional work with more detailed exposure assessment of shift work is warranted. Methods: Using multivariate polytomous logistic regression, we investigated the associations between shift work (evening/night, rotating and other shift schedules) and overweight and obesity as measured by body mass index cross-sectionally among 1561 men. These men had previously participated as population controls in a prostate cancer case-control study conducted in northeastern Ontario from 1995 to 1999. We obtained information on work history (including shift work), height and weight from the existing self-reported questionnaire data. Results: We observed an association for ever (vs. never) having been employed in rotating shift work for both the overweight (OR [odds ratio] = 1.34; 95% CI [confidence interval]: 1.05–1.73) and obese (OR = 1.57; 95% CI: 1.12–2.21) groups. We also observed nonsignificant associations for ever (vs. never) having been employed in permanent evening/night shifts. In addition, we found a significant trend of increased risk for both overweight and obesity with increasing duration of rotating shift work. Conclusion: Both the positive association between rotating shift work and obesity and the suggested positive association for permanent evening/night shift work in this study are consistent with previous findings. Future population-based research that is able to build on our results while examining additional shift work characteristics will further clarify whether some shift patterns have a greater impact on obesity than others