Heather E. Bryant

Effect of cigarette smoking on recurrence of Crohn's disease.

The effect of cigarette smoking on recurrence (defined in this study as the need for repeat surgery) in patients who had previously required surgery for Crohns disease was assessed in a historical cohort of 174 patients. Mean follow-up was 10.8 yr. The 5- and 10-yr recurrence rates were 28% and 56%, respectively. Five- and 10-yr rates were significantly different for smokers (36%, 70%) and nonsmokers (20%, 41%). When patients were stratified by gender, the increased risk was more apparent in women (odds ratio 4.2, 95% confidence interval 2.0-4.2) than in men (odds ratio 1.5, 95% confidence interval 0.8-6.0). Evidence for a dose-response relationship could be identified in women but not men. Cigarette smoking may not only be a risk factor for development of Crohns disease but also may influence disease activity following surgery.

The lifetime total physical activity questionnaire: development and reliability.

OBJECTIVE To develop and test the intra-rater reliability of an interview-administered questionnaire that assesses lifetime patterns of total physical activity including occupational, household, and exercise/sports activities. METHODS The questionnaire was developed and pretested using cognitive interviewing techniques on a sample of women with and without previous breast cancer diagnoses. A pilot study was conducted with 115 women who were interviewed twice, 6 to 8 wk apart by interviewers trained in cognitive interviewing methods. Respondents used recall calendars to record their education, occupations, life events, and physical activity patterns before the interviews. Interviewers helped respondents recall their lifetime exposures, including their occupational, household, and exercise/sports activities, using these calendars and memory-probing strategies. Activity levels were estimated as the average number of hours of activity per week over different time periods. Means and correlation coefficients were estimated and compared for the two time periods. RESULTS The questionnaire was found to be highly reliable. The test-retest correlations for hours per week spent in total lifetime physical activity was 0.74, for lifetime occupational activity was 0.87, for household activity was 0.77, and for exercise/sports activities was 0.72. CONCLUSIONS This is the first questionnaire to measure lifetime physical activity by collecting data on each type of physical activity separately over lifetime and by measuring frequency, intensity, and duration of each activity. It is also the first physical activity questionnaire to be developed, refined, and administered using cognitive-based methods employed in survey research. Respondents were able to reliably recall their lifetime physical activity patterns. This instrument can be used for any disease outcome for which physical activity may be a risk factor.

Influence of physical activity in different age and life periods on the risk of breast cancer

We conducted a population-based case-control study of 1,237 incident breast cancer cases and 1,241 controls in Alberta between 1995 and 1997 to examine the effect of physical activity performed at different ages and life periods on breast cancer risk. In this study, we measured all types of physical activity done throughout life with a questionnaire developed and tested specifically for this study. We found that breast cancer risk was most associated with a risk reduction for activity done later in life, particularly between menopause and the reference year, for which we observed an odds ratio of 0.70 (95% confidence interval = 0.52–0.95). We also stratified the study participants into four categories according to their patterns of physical activity performed before and after menopause. For the women who sustained physical activity throughout life vs those who were never active, we found an odds ratio of 0.58 (95% confidence interval = 0.41–0.83). This study suggests that sustained activity throughout life and particularly activity done later in life may have the most benefit in reducing breast cancer risk.

Breast Implants and Breast Cancer — Reanalysis of a Linkage Study

BACKGROUND In 1992, Berkel and colleagues reported in the Journal the results of their study of the potential association of breast augmentation and breast cancer. The study reported that women who had breast augmentation had a significantly lower subsequent risk of breast cancer (P < 0.01) than the general population, with a standardized incidence ratio of 0.48 overall. Assuming a 10-year induction period (that is, assuming that cancers found within 10 years of the augmentation might have been the result of a process begun before surgery and therefore should not be considered), the reported standardized incidence ratio was 0.16. Problems were later identified involving some of the study methods. This paper reports a second analysis of these data. METHODS We used a data set from Alberta Health Care to identify eligible women with bilateral breast augmentation. Using a combination of deterministic and probabilistic methods, we linked this data set to the Alberta Cancer Registry to identify subsequent breast cancers that developed during the study period. Multiple estimates of standardized incidence ratios were calculated on the basis of differing study-eligibility dates, induction periods, and types of breast-cancer (invasive only or invasive plus in situ). RESULTS The reanalysis found substantial differences in the numbers of person-years at risk, resulting in higher standardized incidence ratios than in the original analysis. The final ratios for all breast cancers, with October 1, 1973, used as the starting date of the study, were 0.76 (95 percent confidence interval, 0.55 to 1.02), 0.85 (95 percent confidence interval, 0.58 to 1.19), and 0.68 (95 percent confidence interval, 0.32 to 1.25) for induction periods of 0, 5, and 10 years, respectively. None of these standardized incidence ratios were significantly different from 1. CONCLUSIONS On the basis of this reanalysis, the incidence of breast cancer among the women who had breast augmentation could not be said to be either significantly higher or lower than that among the general population over the period during which this cohort was followed.

Case‐control study of anthropometric measures and breast cancer risk

A population‐based case‐control study of 1,233 incident breast cancer cases and 1,241 controls was conducted in Alberta between 1995 and 1997 to examine the influence of anthropometric factors on the risk of breast cancer using several newly derived variables. Data on current height, weight and waist and hip circumference were collected by interviewers using standardized methods. Respondents recalled their body weight at each decade from age 20 to the referent year. Several variables were estimated, and unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs). No statistically significant associations for any of the estimated variables with breast cancer risk for premenopausal women (462 cases, 475 controls) were found. The results for postmenopausal women (771 cases, 762 controls) in the highest vs. lowest quartiles were, for waist circumference, OR = 1.30 (95% CI 0.97–1.73); waist–hip ratio, OR = 1.43 (95% CI 1.07–1.93); weight gain since age 20, OR = 1.35 (05% CI 1.01–1.81); difference between maximum and minimum weights over adult lifetime, OR = 1.56 (95% CI 1.16–2.08); and the reference weight minus the minimum weight since age 20, OR = 1.47 (95% CI 1.10–1.97). Statistically significant trends in risk were observed for these variables. Effect modification with hormone replacement therapy use was found for most variables assessed for postmenopausal women, with much stronger associations found among never‐users compared to ever‐users. We found strong evidence that waist–hip ratio and weight gained over lifetime, as assessed by different variables, are postmenopausal breast cancer risk factors. These effects were independent of dietary intake and lifetime total physical activity.

Low uptake of colorectal cancer screening 3 yr after release of national recommendations for screening.

BACKGROUND:National guidelines recommending colorectal cancer (CRC) screening for average risk Canadians were released in 2001. The current study determined rates of CRC screening and predictors of screening 3 yr after the guidelines were released.METHOD:A population-based random digit dial telephone survey of 1,808 Alberta men and women aged 50–74 yr assessed awareness about, and self-reported rates of, screening.RESULTS:More average risk women than men reported a recent screening with a home fecal occult blood test (FOBT) (14.0% vs 9.8%, P = 0.013) but men had slightly higher rates of screening endoscopy in the past 5 yr (4.3% vs 1.6%, P = 0.003). Overall, only 14.3% of average risk adults (N = 1,476) were up-to-date on CRC screening. Multivariable predictors of being up-to-date on CRC screening differed for men and women although a doctors recommendation for screening was a strong predictor for both genders (men OR 5.0, 2.9–8.3, women OR 3.8, 2.3–6.5). Screening for other cancers was also an important predictor in both men and women.CONCLUSION:Three years after the release of national guidelines, rates of screening among average risk adults aged 50–74 yr were very low. Public education programs and primary care interventions to specifically invite average risk adults for screening may be required to increase CRC screening rates.

Breast cancer screening attitudes and behaviors of rural and urban women

This study was carried out to assess the breast cancer knowledge, attitudes, and awareness of women age 40 to 74 in Alberta, a Canadian province of 2.4 million people. This analysis compares the attributes of 538 rural women, defined as those living between 1 and 3 hr drive from the major cities in Alberta, and 735 urban women who lived in one of these two cities. Rural women were found to have the same basic knowledge of breast cancer or perceptions of barriers to mammography, but had more negative attitudes about breast cancer itself. Despite their similar access to physician care, they were less likely to have had a recent clinical breast examination or mammogram (P less than 0.001). These differences remained when adjustment was made for demographic background variables; the adjusted prevalence rate ratio for a screening mammogram in the past 2 years was 0.52 (95% C.I., 0.43, 0.64), and for intention to have a mammogram in the next 2 years, 0.75 (0.63, 0.90). The results suggest particular program delivery strategies when planning for provision of breast screening information and service to the large subgroup of rural women.

Relation between intensity of physical activity and breast cancer risk reduction.

PURPOSE To examine the influence of frequency, duration, and intensity of physical activity on risk of breast cancer and to compare breast cancer risks associated with self-reported versus assigned intensity levels of activity. METHODS A population-based case-control study of 1233 incident breast cancer cases and 1241 controls was conducted in Alberta between 1995 and 1997. The frequency, duration and intensity of occupational, household, and recreational activities were measured throughout lifetime using the Lifetime Total Physical Activity Questionnaire and cognitive interviewing methods. Unconditional logistic regression analyses were used to estimate odds ratios and a full assessment of confounding and effect modification was undertaken. Odds ratios for self-reported and compendium-based assigned levels of activity were compared for lifetime total activity and by type of activity. RESULTS Breast cancer risk reductions were comparable when self-reported and assigned intensity values were used, although the results and trends were more evident with the assigned intensity data. Moderate-intensity occupational and household activities decreased breast cancer risk, whereas recreational activity, at any intensity level, did not contribute to a breast cancer risk reduction. CONCLUSION This study found that moderate-intensity activities were the major contributors to the decrease in breast cancer risk found in this study and that risk reductions were more evident when the frequency and duration of activity alone were modeled. Of the three types of activity considered, the greatest risk reductions observed were for occupational and household activities.

Effect of oral contraceptive use on reoperation following surgery for Crohn's disease

The influence of oral contraceptive (OCP) use as a risk factor for the development of Crohns disease is disputed. We wished to determine if OCP use affected the risk of recurrence (defined as need for a second surgery) in women who had already undergone a resection for Crohns disease. We hypothesized that if contraceptive use was a risk factor for disease development, it could influence recurrence. Using a mail questionnaire, we surveyed 138 women regarding their OCP use following surgery for Crohns disease. All participants were between ages 16 and 35 at the time of their initial surgery which occurred between 1966 and 1984. Ninety-seven women (70%) responded. Mean follow-up was 9.9 years (range 4–27). Forty-six women required a second surgery. The recurrence rate as determined by actuarial analysis, was 27.2% (95% confidence intervals (CI95 16.5–38.1) and 58.0% (CI95 37.8–78.2) at 5 and 10 years, respectively. Thirty-two women took OCP in the first year following surgery. Eleven OCP users (34.4%) required additional surgery compared to 34 (53.1%) of nonusers. Using life table analysis, the percentage requiring a second surgery was 25.0% (CI95 6.9–43.1) and 40.7% (CI95 1.5–80%) at 5 and 10 years, respectively, for users compared to 28.4% (CI95 6.9–43.1) and 64.0% (CI95 40.5–87.5) for nonusers (Lee Desu, P>0.05). When surveyed about their reasons for using OCP, most women stated that their disease did not affect their decision to use contraceptives. There were no significant differences in terms of reasons for using OCP between those who required surgery and those who did not. In conclusion, there was little evidence to support the hypothesis that OCP use increased the risk of requiring a second operation in women who had undergone surgery for Crohns Disease. The small sample size may have prevented detection of a modest effect.

Predictors of Colorectal Cancer Screening: A Comparison of Men and Women

BACKGROUND New Canadian guidelines recommend screening average-risk adults to reduce mortality from colorectal cancer, the second most common cause of cancer death among Canadians. The present study examined the self-reported prevalence of colorectal cancer testing and sex-specific predictors of having had a fecal occult blood (FOB) test for screening, among a cohort of Alberta residents aged 50 to 69 years. METHODS Subjects (n=5009) enrolled in a geographically based cohort study completed a Health and Lifestyle Questionnaire between October 2000 and June 2002 that ascertained their colorectal cancer detection practices, as well as demographic and other health and lifestyle characteristics. RESULTS Patterns of FOB testing, and sigmoidoscopy or colonoscopy, were similar for men and women. The majority of subjects (83.3%) reported no first-degree family history of colorectal cancer or bowel conditions, and they were considered to be at average risk. Few average-risk subjects reported having a screening FOB test within the past two years (7.7% [95% CI 6.7% to 8.7%] of subjects aged 50 to 59 years and 12.5% [95% CI 10.9% to 14.3%] of subjects aged 60 to 69 years). In men, the strongest predictors of having a screening FOB test in the past two years were a recent history of prostate-specific antigen testing and educational attainment. Among women, the strongest predictors were a recent history of having had a Pap test, a recent mammogram, employment status and educational attainment. CONCLUSIONS Screening for colorectal cancer in average-risk adults was infrequent in this sample and lagged behind screening for other cancers. Screening of average-risk adults occurred primarily in people already accessing the health care system, suggesting that public education programs will be required to increase screening rates.