Medscape Medical News > Oncology
Study: 1.3 Million Overdiagnosed Breast Cancers in 30 Years - Nick Mulcahy
This article nicely summarizes a lot of controversy lately regarding breast cancer screening. Long-term studies in Scandinavia and the States are causing quite a paradigm shift. Key points include:
-' "overdiagnosed,"...means their screening-detected tumors would never have led to clinical symptoms'
-'the advent of widespread mammography screening in the United States led to a "substantial increase" in early-stage breast cancer, but only "marginally reduced" the rate of advanced cancers detected. "The imbalance suggests that there is substantial overdiagnosis." '
-'only 8 of the 122 [per 100,000 women] additional early-stage cancers diagnosed were expected to progress to advanced disease'
-'screening is having, at best, only a small effect on the rate of death from breast cancer'
The Canadian Task Force on Preventative Health Care (composed primarily of MDs) has made the following recommendations to health care professionals:
For women aged 40–49 we recommend not routinely screening with mammography. (Weak recommendation; moderate quality evidence)
For women aged 50–69 years we recommend routinely screening with mammography every 2 to 3 years. (Weak recommendation; moderate quality evidence)
For women aged 70–74 we recommend routinely screening with mammography every 2 to 3 years. (Weak recommendation; low quality evidence)
Magnetic Resonance Imaging
We recommend not routinely screening with magnetic resonance imaging. (Weak recommendation; no evidence)
Clinical Breast Exam
We recommend not routinely performing clinical breast exam alone or in conjunction with mammography to screen for breast cancer. (Weak recommendation; low quality evidence)
Breast Self Exam
We recommend not advising women to routinely practice breast self exam. (Weak recommendation; moderate quality evidence)
Here is the link for the Patient FAQ document http://canadiantaskforce.ca/guidelines/2011-breast-cancer/breast-cancer-screening-patient-faq/
It takes time for information like this to be evaluated, absorbed and implemented; but don't be surprised if the recommendations you receive regarding breast cancer screening begin to change in the next few years.
Please don't allow the CBC to ruin fish oil supplements for you! I've looked over all the articles and research referenced in the story below, and there are so many flaws, including:
-the study in the article below evaluates the effects of a very short period of fish oil supplementation on irregular heart beat (arrhythmia) after a specific surgical procedure. Obviously, this very specific scenario can't translate into the general value of fish oil
-many of the studies referenced don't differentiate between fish and plant sources of omega-3. It has not been proven that plant sources of omega-3 are in a form our body can utilize.
-fish oil is generally called EFA (Essential Fatty Acids) and then it is further divided into EPA and DHA content. 1000 mg of 'EFA' does not guarantee a therapeutic dose of EPA and/or DHA.
-fish oils don't (always) work rapidly. You shouldn't expect to a shorten a hospital stay by suddenly starting a fish oil supplement when you check in.
-the article references a Cochrane review which actually said 'There is not enough evidence to say that people should stop taking rich sources of omega 3 fats...' AND some of the research they were reviewing was for a margarine spread!
I could go on and on. I guess what it comes down to is that the news these days is filled with sensational stores. There must be some combination of reporters intentionally skewing the facts and/or just not understanding the science. There is no 'wonder supplement' out there, but there are many that are extremely good. I would encourage you to speak to a health care practitioner you trust when the news raises questions for you.
As a final note, we are starting to discover some wonderful non-fish sources of omega-3 essential fatty acids that hold great promise of being in a form our body can properly use.
This Australian study's preliminary findings were that "On average, every single hour of TV viewed after the age of 25 reduces the viewer's life expectancy by 21.8... min[utes]" Wow!
[Br J Sports Med. 2012;46(13):927-930]
(photo by Nadia Meslem, http://3d.nu)
This is an interesting finding (article copied from Medscape), reminding us that everything is generally best in moderation. To summarize - although vitamin D has been found to assist with bone growth, proper immune cell function, and some elements of cancer control; it has recently been found that people who live longer seem to have lower vitamin D levels. This is an initial finding, meaning more work needs to be done to determine whether vitamin D levels are just a bio marker for some other physiologic process, or directly associated with longevity.
Low Vitamin D Levels Linked to Longer Life
Laurie Barclay, MD
Nov 05, 2012
New genetic findings in those predisposed to longevity cast doubt on whether low levels of vitamin D cause age-related diseases and mortality, according to an analysis from the Leiden Longevity Study published online November 5 in the Canadian Medical Association Journal.
"Vitamin D plays a critical role in bone formation, immune cell differentiation, and in the inhibition of proliferation and angiogenesis in cancer," write Raymond Noordam, MSc, from the Department of Gerontology and Geriatrics at Leiden University Medical Center in the Netherlands, and coauthors. "Low serum levels of 25-hydroxyvitamin D3 (25[OH] vitamin D) are associated with increased mortality, cardiovascular disease, diabetes mellitus, cancer, multiple sclerosis, allergy, asthma, infection, depression, mental illness and musculoskeletal pain. However, because of design limitations, previous studies have not been able to infer causality."
The goal of this study was to examine a possible causal association between low levels of 25(OH) vitamin D and various age-related diseases and mortality. The Leiden Longevity Study allowed assessment of vitamin D levels in the middle-aged offspring of nonagenarians who had 1 or more nonagenarian siblings, using a sample of 380 white families with 2 or more siblings at least 89 years of age for men or 91 years of age for women. This was useful because the prevalence of age-related diseases is lower in these offspring than in the general population, and they are more likely to survive to old age.
Control patients (n = 461) were the partners of the offspring (n =1038) and were of similar age and had similar environmental exposures that could affect vitamin D levels. In addition to anthropometric measurements, 25(OH) vitamin D levels, parathyroid hormone levels, and dietary vitamin D intake, the investigators studied single nucleotide polymorphisms (SNPs) in 3 genes known to be associated with vitamin D levels.
Compared with the control participants, the offspring had significantly lower levels of vitamin D (64.3 nmol/L vs 68.4 nmol/L; P= .002). These findings were independent of possible confounding factors (age, sex, body mass index, month of blood sampling, tanning bed use, dietary and supplemental vitamin D intake, and creatinine levels). Levels of parathyroid hormone did not differ between groups.
The rs2060793 genetic variant in the CYP2R1 gene occurred less frequently in the offspring than in the control participants (P= .04). Across the 2 most prevalent genotypes of this SNP, there was a persistent difference in vitamin D levels between offspring and control patients.
"Compared with controls, the offspring of nonagenarians who had at least one nonagenarian sibling had a reduced frequency of a common variant in the CYP2R1 gene, which predisposes people to high vitamin D levels; they also had lower levels of vitamin D that persisted over the 2 most prevalent genotypes," the study authors write. "These results cast doubt on the causal nature of previously reported associations between low levels of vitamin D and age-related diseases and mortality."
Limitations of this study include the availability of data on tanning bed use and sun exposure for only a small, but random, subpopulation of participants. In addition, the analyses excluded 36% of participants because of missing data on possible confounding factors. However, the excluded participants also showed similar differences in vitamin D levels between offspring and control patients, suggesting they were representative of the total study group.
The investigators put forth a theory that the offspring of nonagenarians may have increased expression of the klotho protein, which is thought to be an "aging suppressor" protein.
"We found that familial longevity was associated with lower levels of vitamin D and a lower frequency of allelic variation in theCYP2R1 gene, which was associated with higher levels of vitamin D," the study authors conclude. "Future research should focus on elucidating the mechanisms that explain the lower 25(OH) vitamin D levels in familial longevity and other genetic variants associated with vitamin D metabolism, such as the vitamin D receptor."
The study was supported by the Innovation Oriented Research Program on Genomics, the Center for Medical Systems Biology, and the Netherlands Genomics Initiative/Netherlands Organisation for Scientific Research. The study authors have disclosed no relevant financial relationships.
CMAJ. Published online November 5, 2012. Abstract
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Cite this article: Low Vitamin D Levels Linked to Longer Life. Medscape. Nov 05, 2012.
Dr. Dielle Raymond, ND