Association of lifestyle and other risk factors with breast cancer according to menopausal status: a case-control study in the Region of Western Pomerania (Poland).

PURPOSES: The purpose of this study was to examine the association between family history, reproductive, anthropometric, lifestyle factors and risk of breast cancer according to menopausal status, using data from a case-control study conducted in the Region of Western Pomerania (Poland). METHODS: A total, 858 women with histological confirmed breast cancer and 1085 controls, free of any cancer diagnosis, aged 28-78 years, were included in the study. The study was based on a self-administered questionnaire. Logistic regression was used to compute odds ratios and 95% confidence intervals and a broad range of potential confounders was included in analysis. RESULTS: Protective effect of a late age at menarche, a longer period of breast-feeding, increased levels of: recreational physical activity, total vegetables or fruits intake, and intake of vitamins on the risk of breast cancer was observed among both pre- and post-menopausal women. Familial history of breast cancer, active or passive smoking, experience of a crude psychological stress were positively associated with breast cancer regardless menopausal status. Current body weight, current body mass index, increased alcohol intake elevated breast cancer risk in postmenopausal women, while these factors did not alter risk among premenopausal women. Increased consumption of red meat or animal fats elevated the risk in premenopausal women. More educated premenopausal women had lower breast cancer than those graduated from elementary school. Low family income increased the risk in premenopausal women. CONCLUSION: There is evidence for a dose-response relationship between several lifestyle factors and breast cancer risk. The results also suggest that some different mechanisms may operate in breast cancer etiology in pre-and post-menopausal women. A multifactorial process of breast cancer development, the complex interaction between physical activity, diet, energy intake and body weight, inconsistent and inconclusive data on breast cancer risk factors coming even from well-designed epidemiological studies are the case for continual update knowledge on primary prevention and identification of changes in behavior that will reduce the risk.

Physical activity in the prevention of the most frequent chronic diseases: an analysis of the recent evidence.

BACKGROUND: Physical activity is widely recognized as a means for the primary prevention of chronic diseases as well as in patients' treatment and rehabilitation. Moreover, activity has beneficial effects on an individual's health and well-being. Despite the benefits of regular physical activity, the percentage of physically inactive adults in the world is high. Environmental and policy approaches aimed to increase physical activity require continual stress of the epidemiological evidence from studies investigating disease mechanisms as well as controlled clinical trials. PURPOSE: To update the evidence that physical activity/exercise is important for reducing the chronic diseases (cardiovascular and heart, diabetes, cancer, obesity, osteoporosis, and fall-related injuries, depression and emotional stress) and for mechanisms that may operate in the relation between physical activity and a disease risk. METHODS: Research studies published from 2004 through to March 2007 were identified through a review of the literature available on the NLM PubMed, Medline, Current Contents, and Elsevier-Science Direct databases. RESULTS: Recent evidence on physical activity/exercise and reduction of chronic major diseases incidence and rehabilitation of patients replicates previous findings. The strongest evidence exists for colon cancer, breast cancer, and cardiovascular diseases. The maximal magnitudes of the risk reduction reported were: 75% for breast cancer, 49% for cardiovascular and heart diseases, 35% for diabetes, 22% for colorectal cancer. Increased physical activity also prevented the weight gain associated with aging at least 2-times greater in individuals who were more active compared with those who were inactive. Limited new findings has been reported for the beneficial role of physical activity in fall-related injures, depression and emotional distress. CONCLUSION: Recent evidence confirms previous findings that engaging in moderate physical activity is very important for the primary prevention of chronic diseases, decreasing all causes of mortality and that exercise is one of the determinants for physical and psychological well-being. The current evidence provides further support that physical activity can suppress concentrations of 17 alpha-estradiol in women.

Self-reported childhood physical activity and breast cancer in adulthood.

The association between physical activity during childhood and breast cancer risk was examined. To study this question data on physical activity in childhood were analyzed. A hospital-based case-control study of 250 Polish incident breast cancer cases (49.2% of eligible) and 301 (41.4% of all selected) frequency matched for age controls was conducted in 2003-2004 in the Region of Western Pomerania. Women were asked to compare their total physical activity at ages 10-12 years and 13-15 years with the activity of their female peers by choose from one of three categories: less active, equally active, more active, the best describing their activity. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using univariate and multivariate logistic regression, fitted by the method of maximum likehood. Women who reported having been physically more active than their peers at ages 10-12 years had an age-adjusted OR=0.88 (95% CI=0.36-2.15, P for trend=0.37) as compared with those reported being less active. Adjustment for potential confounders and total lifetime physical activity decreased the risk estimate to OR=0.25 (95% CI=0.06-1.10, P for trend=0.15). For physical activity at ages 13-15 years, both an age-adjusted and multivariate adjusted ORs were also decreased among women who were at least such active as their peers, but the reductions were not statistically significant. For women who were more physically active than their peers during both age periods the adjusted OR was 0.30 (95% CI=0.11-1.34, P for trend =0.21). These results show no protective role for physical activity in childhood on breast cancer development among women aged 35-75 years. Further investigations employing larger sample sizes with comprehensive assessment of physical activity during the childish years are needed to verify this evidence.

Physical activity in the prevention of cancer.

OBJECTIVE: The purpose of this paper is to update epidemiological research on relations between physical activity and cancer risk, including physical activity measurement and potential mechanisms of prevention of cancer. DESIGN: Review of recent systematic reviews, meta-analyses and studies on the topic that have been published in the recent literature. RESULTS: Convincing epidemiological evidence exists that physical activity reduces colon and breast cancers. The evidence is weaker for prostate (classified as probable), lung and endometrial cancers (classified as possible), and insufficient for cancers at all other sites. Hypothesized biological mechanisms for the physical activity--cancer association include changes in hormone level, reduced percentage of body fat, enhancement of the immune system, and alteration in free radical damage by scavenger systems. The available data indicate that 30-60 minutes per day of moderate-to-vigorous physical activity is needed to be protective against breast and colon cancers. CONCLUSION: A greater understanding of the biological mechanisms operating in the physical activity--cancer relation, complete measurements of physical activity through a subject's life, assessment of all potential confounders and association modifiers are needed to confirm a protective role of physical activity in cancer development and allow specific exercise prescriptions for prevention in particular cancer sites.