Sunday, November 09, 2008


I thought at first that this would be just a chance result of data dredging but the work, as presented, does seem a little better than that. A reasonable hypothesis was generated and epidemiological data was sought to examine it. One understands the absence of an in vivo test but that absence does leave the evidence shaky. So MUCH more epidemiological data is needed before the association can be taken seriously. Even in the highly selective "sample" used, however, the association of migraine with cancer was not strong (lots of migraine sufferers DID get cancer) -- so there may not be a lot of point in further work. Popular summary plus journal abstract below:

In a puzzling twist, women who have a history of migraine headaches are far less likely to develop breast cancer than other women, U.S. researchers said on Thursday. The study is the first to look at the relationship between breast cancer and migraines and its findings may point to new ways of reducing a woman's breast cancer risk, they said.

"We found that, overall, women who had a history of migraines had a 30 percent lower risk of breast cancer compared to women who did not have a history of such headaches," said Dr. Christopher Li of the Fred Hutchinson Cancer Research Center in Seattle, whose findings appear in the journal Cancer Epidemiology, Biomarkers and Prevention. Li said the reduction in risk was for the most common types of breast cancers -- those driven by hormones, such as estrogen-receptor positive breast cancer, which is fueled by estrogen, and progesterone-receptor positive breast cancer, which is fueled by progesterone.

Hormones also play a role in migraines, a brutal type of headache often accompanied by nausea, vomiting and heightened sensitivity to light and sound. Women are two to three times more likely than men to get migraines.

While it is not exactly clear why women with a history of migraines had a lower risk for breast cancer, Li and colleagues suspect hormones are playing a role. "Women who have higher levels of estrogen in their blood have higher levels of breast cancer," Li said in a telephone interview. And he said migraines are often triggered by low levels of the hormone estrogen, such as when estrogen levels fall during a woman's menstrual cycle. Women who get migraines "may have a chronically lower baseline estrogen. That difference could be what is protective against breast cancer," Li said.

For the study, Li and colleagues analyzed data from two studies of 3,412 post-menopausal women in the Seattle area, 1,938 of whom had been diagnosed with breast cancer and 1,474 of whom had no history of breast cancer. Women in the study provided information on their migraine history. They found women who had reported a clinical diagnosis of migraine had a 30 percent reduced risk of developing hormonally sensitive breast cancers.

"Migraines are typically most severe among pre-menopausal women," Li said. "This study was all post-menopausal women." He said that suggests the protective effect seen in women who get migraines may have a lasting effect at reducing breast cancer risk. "While these results need to be interpreted with caution, they point to a possible new factor that may be related to breast-cancer risk," Li said in a statement.


Migraine in Postmenopausal Women and the Risk of Invasive Breast Cancer

By Robert W. Mathes et al.

Background: The frequency of migraine headache changes at various times of a woman's reproductive cycle. Menarche, menses, pregnancy, and perimenopause may carry a different migraine risk conceivably because of fluctuating estrogen levels, and in general, migraine frequency is associated with falling estrogen levels. Given the strong relationship between endogenous estrogen levels and breast cancer risk, migraine sufferers may experience a reduced risk of breast cancer.

Methods: We combined data from two population-based case-control studies to examine the relationship between migraine and risk of postmenopausal invasive breast cancer among 1,199 ductal carcinoma cases, 739 lobular carcinoma cases, and 1,474 controls 55 to 79 years of age. Polytomous logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI).

Results: Women who reported a clinical diagnosis of migraine had reduced risks of ductal carcinoma (OR, 0.67; 95% CI, 0.54-0.82) and lobular carcinoma (OR, 0.68; 95% CI, 0.52-0.90). These associations were primarily limited to hormone receptor–positive tumors as migraine was associated with a 0.65-fold (95% CI, 0.51-0.83) reduced risk of estrogen receptor–positive (ER+)/progesterone receptor–positive (PR+) ductal carcinoma. The reductions in risk observed were seen among migraine sufferers who did and did not use prescription medications for their migraines.

Conclusions: These data suggest that a history of migraine is associated with a decreased risk of breast cancer, particularly among ER+/PR+ ductal and lobular carcinomas. Because this is the first study to address an association between migraine history and breast cancer risk, additional studies are needed to confirm this finding.

Cancer Epidemiology Biomarkers & Prevention 17, 3116-3122, November 1, 2008

Vaccine to halt progress of Alzheimer's disease?

A revolutionary jab that scientists believe could stop Alzheimer's disease in its tracks is being tested on patients. Initial results indicate it could stop sufferers from reaching the devastating final stages of the disease, which can destroy the ability to walk, talk and even swallow. Scientists are said to be excited after a year-long trial on sufferers. However the drug, effectively a vaccine, is not expected to repair the damage already done to patients, so would not be a cure.

Current Alzheimer's drugs - some of which have not been approved for use on the NHS - can halt the progression of the disease for some patients but effects wear off over time. In contrast, it is hoped the new jab will hold the disease - the most common form of dementia - at bay indefinitely. The vaccine generates antibodies that seek out and destroy the sticky protein that clogs the brain in Alzheimer's sufferers. When the jab was given to mice suffering an Alzheimer's-like disease, 80 per cent of the amyloid protein patches or plaques were broken up.

Now it has been given to people for the first time, with promising results. In a year-long trial, researchers from the Karolinska Institute in Sweden gave 31 men and women with mild or moderate Alzheimer's regular injections of the vaccine. Tests showed the drug, which is known as CAD106, triggered the production of anti-amyloid antibodies in two-thirds of cases and was safe to use. However, most patients did suffer side-effects, including headaches and nasal problems.

British experts called the results 'encouraging' but cautioned that other promising jabs had failed to come to fruition. Professor Clive Ballard, of the Alzheimer's Society, said the vaccine might be of most benefit to those in the very early stages of the disease. He said: 'The current treatments are better than nothing and probably buy people between six and 12 months of improved function. 'But what they don't do is change the underlying disease. 'If you could target people really early on, presumably you could really slow down the progression of the disease and give people a much longer period of quality function.'

Scientists hope the vaccine could be used to immunise those with a family history of the disease. A mass vaccination of people in late middle-age could even be possible. It is believed half of the 434 billion spent on Alzheimer's in Britain each year could be saved if patients developed the disease five years later than they do now.

Rebecca Wood, of the Alzheimer's Research Trust, called the idea of breaking-up amyloid 'really attractive' but warned it was unclear whether this would improve health. The drug, developed by Swiss biotechnology firm Cytos, has been sold to Swiss pharmaceutical giant Novartis. During its trial, four suffered serious reactions but they were not believed to be caused by the jab. Two more studies are already under way. However, experts warn it could be a decade before the jab hits the market.


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