Mounting evidence, particularly from prospective epidemiologic studies but with additional support from animal models and mechanistic studies, supported conclusions in 2016 by the International ...Agency for Research on Cancer (IARC) in their review of the preventive effects of weight control on cancer risk.
The workgroup concluded that obesity is causally related to cancer at 13 anatomic sites (esophagus: adenocarcinoma; gastric cardia; colon and rectum; liver; gallbladder; pancreas; breast: postmenopausal; uterine endometrial; ovary; kidney: renal cell; meningioma; thyroid; and multiple myeloma). Further, avoiding weight gain and excess body fat will prevent cancer. Evidence on weight loss and reduction in risk of cancer is more limited. Ongoing clinical trials address the benefits of weight loss interventions after diagnosis.
Here, we review the evidence from the 2016 IARC that obesity is causally related to cancer at 13 anatomic sites and identify areas for future research, including the consequences of childhood adiposity, the relation between velocity of weight gain and cancer risk, and improved methods for analysis of life-course adiposity and cancer risk. Refining understanding of mechanisms may further inform prevention strategies.
Implementation science studies the use of strategies to adapt and use evidence-based interventions in targeted settings (e.g., schools, workplaces, health care facilities, public health departments) ...to sustain improvements to population health. This nascent field of research is in the early stages of developing theories of implementation and evaluating the properties of measures. Stakeholder engagement, effectiveness studies, research synthesis, and mathematical modeling are some of the methods used by implementation scientists to identify strategies to embed evidence-based interventions in clinical and public health programs. However, for implementation science to reach its full potential to improve population health the existing paradigm for how scientists create evidence, prioritize publications, and synthesize research needs to shift toward greater stakeholder input and improved reporting on external validity. This shift will improve the relevance of the research that is produced and provide information that will help guide decision makers in their selection of research-tested interventions.
Obesity and Cancer Wolin, Kathleen Y.; Carson, Kenneth; Colditz, Graham A.
The oncologist (Dayton, Ohio),
01/2010, Letnik:
15, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Weight, weight gain, and obesity account for approximately 20% of all cancer cases. Evidence on the relation of each to cancer is summarized, including esophageal, thyroid, colon, renal, liver, ...melanoma, multiple myeloma, rectum, gallbladder, leukemia, lymphoma, and prostate in men; and postmenopausal breast and endometrium in women. Different mechanisms drive etiologic pathways for these cancers. Weight loss, particularly among postmenopausal women, reduces risk for breast cancer. Among cancer patients, data are less robust, but we note a long history of poor outcomes after breast cancer among obese women. While evidence on obesity and outcomes for other cancers is mixed, growing evidence points to benefits of physical activity for breast and colon cancers. Dosing of chemotherapy and radiation therapy among obese patients is discussed and the impact on therapy‐related toxicity is noted. Guidelines for counseling patients for weight loss and increased physical activity are presented and supported by strong evidence that increased physical activity leads to improved quality of life among cancer survivors. The “Five A's” model guides clinicians through a counseling session: assess, advise, agree, assist, arrange. The burden of obesity on society continues to increase and warrants closer attention by clinicians for both cancer prevention and improved outcomes after diagnosis.
The article examines the importance of managing weight to reduce risk for developing cancer and for survival among cancer patients and presents a set of strategies that can be useful to guide clinical advice to patients for whom weight control is an important adjunct to risk management or to improve quality of life and disease‐free survival after diagnosis.
Mammography remains the primary screening strategy for breast cancer, which continues to be the most prevalent cancer diagnosis among women globally. Because screening mammograms capture both the ...left and right breast, there is a nonnegligible correlation between the pair of images. Previous studies have explored the concept of averaging between the pair of images after proper image registration; however, no comparison has been made in directly utilizing the paired images. In this paper, we extend the bivariate functional principal component analysis over triangulations to jointly characterize the pair of imaging data bounded in an irregular domain and then nest the extracted features within the survival model to predict the onset of breast cancer. The method is applied to our motivating data from the Joanne Knight Breast Health Cohort at Siteman Cancer Center. Our findings indicate that there was no statistically significant difference in model discrimination performance between averaging the pair of images and jointly modeling the two images. Although the breast cancer study did not reveal any significant difference, it is worth noting that the methods proposed here can be readily extended to other studies involving paired or multivariate imaging data.
Abstract
Although the need for addressing matching in the analysis of matched case-control studies is well established, debate remains as to the most appropriate analytical method when matching on at ...least 1 continuous factor. We compared the bias and efficiency of unadjusted and adjusted conditional logistic regression (CLR) and unconditional logistic regression (ULR) in the setting of both exact and nonexact matching. To demonstrate that case-control matching distorts the association between the matching variables and the outcome in the matched sample relative to the target population, we derived the logit model for the matched case-control sample under exact matching. We conducted simulations to validate our theoretical conclusions and to explore different ways of adjusting for the matching variables in CLR and ULR to reduce biases. When matching is exact, CLR is unbiased in all settings. When matching is not exact, unadjusted CLR tends to be biased, and this bias increases with increasing matching caliper size. Spline smoothing of the matching variables in CLR can alleviate biases. Regardless of exact or nonexact matching, adjusted ULR is generally biased unless the functional form of the matched factors is modeled correctly. The validity of adjusted ULR is vulnerable to model specification error. CLR should remain the primary analytical approach.
CONTEXT Multiple studies have linked alcohol consumption to breast cancer risk, but the risk of lower levels of consumption has not been well quantified. In addition, the role of drinking patterns ...(ie, frequency of drinking and “binge” drinking) and consumption at different times of adult life are not well understood. OBJECTIVE To evaluate the association of breast cancer with alcohol consumption during adult life, including quantity, frequency, and age at consumption. DESIGN, SETTING, AND PARTICIPANTS Prospective observational study of 105 986 women enrolled in the Nurses' Health Study followed up from 1980 until 2008 with an early adult alcohol assessment and 8 updated alcohol assessments. MAIN OUTCOME MEASURES Relative risks of developing invasive breast cancer. RESULTS During 2.4 million person-years of follow-up, 7690 cases of invasive breast cancer were diagnosed. Increasing alcohol consumption was associated with increased breast cancer risk that was statistically significant at levels as low as 5.0 to 9.9 g per day, equivalent to 3 to 6 drinks per week (relative risk, 1.15; 95% CI, 1.06-1.24; 333 cases/100 000 person-years). Binge drinking, but not frequency of drinking, was associated with breast cancer risk after controlling for cumulative alcohol intake. Alcohol intake both earlier and later in adult life was independently associated with risk. CONCLUSIONS Low levels of alcohol consumption were associated with a small increase in breast cancer risk, with the most consistent measure being cumulative alcohol intake throughout adult life. Alcohol intake both earlier and later in adult life was independently associated with risk.
PDF
