Sunday, March 24, 2013

Risk Factors for Breast Cancer



Breast cancer is a commonly diagnosed cancer in women after non-melanoma skin cancer, and it is the second leading cause of cancer deaths after lung cancer.

heredity and cancer, breast cancer, inherited ...
heredity and cancer, breast cancer, inherited factors vs. other factors (Photo credit: Wikipedia)
Family History of Breast Cancer
It has been seen in studies in adult populations, 5% to 10% of women have a mother or sister with breast cancer, and about twice as many have either a first-degree relative (FDR) or a second-degree relative with breast cancer.
Risk increases with the number of affected relatives, age at diagnosis, and the number of affected male relatives
Genetically predisposed/Inheritance
Autosomal dominant inheritance of breast cancer is characterized by transmission of cancer predisposition from generation to generation, through either the mother’s or the father’s side of the family, with the following characteristics:
  • Multiple cancers within a family.
  • Cancers typically occur at an earlier age than in sporadic cases (defined as cases not associated with genetic risk).
  • Two or more primary cancers in a single individual. These could be multiple primary cancers of the same type (e.g., bilateral breast cancer) or primary cancer of different types (e.g., breast cancer and ovarian cancer in the same individual).
  • Cases of male breast cancer.
Other Risk Factors for Breast Cancer include age, reproductive and menstrual history, hormone therapy, radiation exposure, mammographic breast density, alcohol intake, physical activity, anthropometric variables, and a history of benign breast disease
  • Age
·         Risk of breast cancer increases with age, with most breast cancers occurring after age 50 years. In women with a genetic susceptibility, breast cancer, tends to occur at an earlier age than in sporadic cases.
  • Use of Oral Contraceptives
·         Oral contraceptives use are not entirely consistent, however, use of OCs formulated before 1975 was associated with an increased risk of breast cancer.
·         Oral contraceptives (OCs) may produce a slight increase in breast cancer risk among long-term users, but this appears to be a short-term effect.
  • Hormone replacement therapy (HRT)
·         Data exist from both observational and randomized clinical trials regarding the association between postmenopausal HRT and breast cancer.
·         Short-term use of hormones for treatment of menopausal symptoms appears to confer little or no breast cancer risk.
·         Local use of hormone cream is safer than oral preparations.
  • Age at Menarche, Parity and Menopause.
·         In general, breast cancer risk increases with early menarche, late menopause; and is reduced by early first full-term pregnancy.
·         In contrast to ER-positive breast cancers, parity has been positively associated with triple-negative disease, with no association with ages at menarche and menopause.
  • Radiation exposure
·         Observations in survivors of the atomic bombings of Hiroshima and Nagasaki and in women who have received therapeutic radiation treatments to the chest and upper body document increased breast cancer risk as a result of radiation exposure.
·         The significance of this risk factor in women with a genetic susceptibility to breast cancer is unclear.
·         Frequent mammograms are also not recommended.
  • Alcohol intake
·         The risk of breast cancer increases by approximately 10% for each 10 g of daily alcohol intake (approximately one drink or less) in the general population. Prior studies of BRCA1/BRCA2 mutation carriers have found no increased risk associated with alcohol consumption.
  • Physical activity and anthropometry
·         Weight gain and being overweight are commonly recognized risk factors for breast cancer. In general, overweight women are most commonly observed to be at increased risk of postmenopausal breast cancer and at reduced risk of premenopausal breast cancer. Sedentary lifestyle may also be a risk factor. One study suggested a reduced risk of cancer associated with exercise among BRCA1 and BRCA2 mutation carriers.
  • Benign breast disease (BBD) and mammographic density
·         Benign breast disease (BBD) is a risk factor for breast cancer, independent of the effects of other major risk factors for breast cancer (age, age at menarche, age at first live birth, and family history of breast cancer). There may also be an association between BBD and family history of breast cancer.
·         An increased risk of breast cancer has also been demonstrated for women who have increased density of breast tissue as assessed by mammogram, and breast density is likely to have a genetic component in its etiology.
With a normal active lifestyle, balanced diet; and breast self examination can beat the dreaded cancer to a larger extent.

Enhanced by Zemanta

Friday, March 8, 2013

High Calcium Intake may not be Good, Rather may Increase ALL Cause Mortality


In Sanskrit there is an proverbial advice, "Ati Sarbatra Gahirtam"; that means, 'Too much of anything is bad". Also there a similar, but more elaborate proverbial advice, "Jala gahale srusti nasa and jala bihune srusti Nasa"; that means, if there is excess of water there is destruction also same happens in absence of water, something like famine and flood.
As we know calcium is a vital mineral for functioning of our system, from muscle contraction to keeping bone stronger. People start taking it in the faith that it will improve health; or at least keep them fit for work.
Now, in a study of women in the Swedish mammography cohort, it was seen that a high calcium intake (>1400 mg/day) was associated with an increased rate of mortality, including death from cardiovascular disease. 
The increase was moderate with a high dietary calcium intake without supplement use, but the combination of a high dietary calcium intake and calcium tablet use resulted in a more pronounced increase in mortality. For most women with lower intakes we observed only modest differences in risk.
Possible cause can me:
Calcium levels in serum are under tight homeostatic control, and calcium intake is not normally correlated with calcium serum levels. Diets that are low or very high in calcium can, however, override normal homeostatic control causing changes in blood levels of calcium or calciotropic hormones. 
Calcium enriched meals can reduce calcitriol, the active vitamin D metabolite, by inhibition of 1α hydroxylase and also increase serum levels of fibroblast growth factor. Higher levels of circulating fibroblast growth factor 23 are associated with an increased risk of cardiovascular events and all cause mortality.
English: Overview of calcium regulation (See W...
English: Overview of calcium regulation (See Wikipedia:Calcium in biology). To discuss image, please see Talk:Human body diagrams References Page 1094 (The Parathyroid Glands and Vitamin D) in: Walter F., PhD. Boron (2003). Medical Physiology: A Cellular And Molecular Approaoch, 1300, Elsevier/Saunders. (Photo credit: Wikipedia)

In addition, fibroblast growth factor 23 downregulates calcitriol levels. Vitamin D suppression leads to an upregulation of the renin-angiotensin-aldosterone system and hypertension, higher levels of proinflammatory cytokines involved in the pathogenesis of atherosclerosis, increased carotid artery intima medial thickness, decreased endothelial function, hypertrophy of cardiac and vascular muscle cells, and a possible increase in serum triglycerides. Finally, high serum calcium levels can increase the risk of cardiovascular mortality by induction of a hypercoagulable state.
Emphasis should be placed on people with a low intake of calcium rather than increasing the intake of those already consuming satisfactory amounts.
When looking at the totality of our data, high calcium intakes were associated with higher rates of death from all causes and cardiovascular disease. Mortality was not increased between 600 and 1400 mg/day of total calcium intake, the most customary levels of intake in this setting. 

In summary,
  • A low calcium intake is associated with higher fracture rates in elderly people and a higher risk of stroke and fatal ischaemic heart disease
  • Meta-analyses of some randomised studies have, however, shown a higher risk of incident ischaemic heart disease and stroke with calcium supplement use
  • In observational studies, use of calcium supplements has been associated with both lower overall and cardiovascular mortality rate, as well as higher incidence of cardiovascular disease.
  • In this Swedish cohort study of women, high intakes of calcium (>1400 mg/day) were associated with higher mortality
  • The increase was moderate with a high dietary calcium intake without supplement use, but more pronounced with a high dietary calcium intake with calcium tablet use.
  • Mortality was not increased between 600 and 1400 mg/day of total calcium intake, the most customary levels of intake in this setting. 
  • For most women with lower calcium intakes only modest differences in risk were observed.


The original article published in the BMJ may be accessed here.
Enhanced by Zemanta

Featured Post

Cyclodextrin for Treatment of Atherosclerosis

Cardiovascular disease from atherosclerosis is one of the most common causes of death worldwide. Inflammation plays a crucial role in ...