(Press-News.org) Insulin resistance, a condition in which insulin produced by the body becomes less effective in reducing blood glucose levels, appears to be associated with an increased risk of stroke in individuals without diabetes, according to a report in the October issue of Archives of Neurology, one of the JAMA/Archives journals.
Insulin resistance originates from several factors, including genetics, a sedentary lifestyle and obesity, according to background information in the article. The condition contributes significantly to the risk of cardiovascular disease, but whether it predicts ischemic stroke (interruption in blood flow to the brain due to a blood clot or another artery blockage) is still a matter of debate.
One widely used tool to estimate insulin sensitivity is the homeostasis model assessment (HOMA), calculated using fasting blood glucose and fasting insulin levels. Tatjana Rundek, M.D., Ph.D., of Miller School of Medicine, University of Miami, and colleagues assessed insulin resistance using HOMA for 1,509 non-diabetic participants in the Northern Manhattan Study, a study assessing stroke risk, incidence and prognosis in a multi-ethnic urban community. Participants were followed for an average of 8.5 years.
During the follow-up period, vascular events occurred in 180 participants, including 46 who had fatal or non-fatal ischemic strokes, 45 who had fatal or non-fatal heart attacks and 121 who died of vascular causes. Individuals in the top one-fourth (quartile) of HOMA index had an increased risk of stroke compared to those in the other three quartiles of the HOMA index. Adjusting for established cardiovascular risk factors—including glucose level, obesity and metabolic syndrome—did not diminish the association. The relationship between insulin resistance and the risk of first stroke was stronger in men than women but did not vary by racial or ethnic group.
Individuals in the top quarter of insulin resistance had a 45 percent greater risk of any type of vascular event. However, insulin resistance was not associated with heart attack or vascular death separately.
"There are several possible reasons for the stronger effect of insulin resistance on the risk of ischemic stroke than of myocardial infarction in the present study compared within other studies," the authors write. It may be because individuals with a history of heart attack were excluded from this study, or because factors associated with insulin resistance—including high blood pressure, high triglyceride levels and low HDL or "good" cholesterol levels—are more significant risk factors for stroke than for heart attack.
"These findings emphasize the need to better characterize individuals at increased risk for ischemic stroke and the potential role of primary preventive therapies targeted at insulin resistance," the authors conclude.
(Arch Neurol. 2010;67[10]:1195-1200. Available pre-embargo to the media at www.jamamedia.org.)
Editor's Note: This study was supported by the Gilbert Baum Memorial Grant and the Goddess Fund for Stroke Research in Women, by grants from the National Institute of Neurological Disorders and Stroke, by the Kathleen Scott Research Fellowship from the American Heart Association and a grant from the General Clinical Research Center. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
Editorial: Insulin Resistance Can Be Used to Refine Risk Stratification
"The implications of these findings are exciting if insulin resistance can be proven to be a causal risk factor for stroke (rather than a marker of increased risk) because insulin resistance cannot only be measured but also treated," write Graeme J. Hankey, M.D., F.R.C.P., F.R.C.P.(Edin), F.R.A.C.P., of University of Western Australia, Perth, and Tan Ze Feng, M.D., of the First Affiliated Hospital of Jinan University, Guangzhou, China, and both also of Royal Perth Hospital, Perth, Australia, in an accompanying editorial.
"To establish a causal relationship between insulin resistance and stroke, it is necessary to not only show that insulin resistance is an independent, significant risk factor for stroke, as reported by Rundek et al, but also that removing or minimizing exposure to insulin resistance is associated with a reduction in the incidence of stroke," they write.
Clinical trials to establish this relationship are under way, they note. In the meantime, "we can take confidence from the study of Rundek et al that measuring insulin resistance may help refine prognostic estimates of future risk of stroke obtained by means of traditional risk stratification schemes. Although it is premature to widely screen for insulin resistance as a means to prevent stroke, its measurement may have a role in particular cases in which traditional risk stratification schemes suggest that the patient is at intermediate risk of stroke (rather than high or low risk) and in whom an additional finding of insulin resistance may be sufficiently compelling to supplement lifestyle advice with pharmacological interventions to lower stroke risk."
(Arch Neurol. 2010;67[10]:1177-1178. Available pre-embargo to the media at www.jamamedia.org.)
Editor's Note: This study was supported by a grant from the China Scholarship Council. Please see the article for additional information, including author contributions and affiliations, financial disclosures, funding and support, etc.
###
END
The number of Medicare recipients undergoing treatment for retinal conditions nearly doubled between 1997 and 2007, with significant shifts in the types of procedures most commonly performed, according to a report in the October issue of Archives of Ophthalmology, one of the JAMA/Archives journals.
"Retinal disease is highly prevalent among older individuals, and both age-related macular degeneration (AMD) and diabetic retinopathy account for more than half the irreversible blindness in older Americans. The prevalence of both macular degeneration and diabetic retinopathy ...
Newer treatments for age-related macular degeneration (AMD)—including an intravitreous (into the eye) injection of a chemotherapy drug and use of a related compound approved for use against the eye disease—do not appear to be associated with an increased risk of cardiovascular complications or death when compared with existing therapies, according to a report in the October issue of Archives of Ophthalmology, one of the JAMA/Archives journals.
"More than 1.5 million older Americans have age-related macular degeneration, the most common cause of irreversible vision loss ...
The Financial Markets Group at the London School of Economics carried out the research. It developed a life-cycle model to investigate how prices of housing (purchasing and renting), the overall economy and wealth distribution react to changes in technology and financial conditions.
There were a number of conclusions from the investigation, including:
stricter limitations on land development result in less residential building, which tends to push up rental and purchase prices;
availability of land for residential development is more important than availability of capital ...
Adding topotecan to carboplatin plus paclitaxel, the standard treatment for ovarian cancer, does not improve progression-free survival in patients and leads to greater toxicity, according to a study published online October 11 in the Journal of the National Cancer Institute.
Cisplatin plus paclitaxel, and carboplatin plus paclitaxel, are the most widely accepted first-line regimens for advanced epithelial ovarian cancer. Still, most women relapse and die from their disease. One possible solution is to add a third agent, such as topotecan, which has activity in the treatment ...
INDIANAPOLIS – Twenty-two physical symptoms associated with cancer – symptoms often unrecognized and undertreated – are prevalent in all types of cancers regardless of whether the patient is newly diagnosed, undergoing treatment or is a cancer survivor, according to researchers from the Regenstrief Institute and the Indiana University schools of medicine and nursing.
Common symptoms include fatigue, pain, weakness, appetite loss, dry mouth, constipation, insomnia and nausea. These physical symptoms are associated with substantial functional impairment, disability and ...
CAMBRIDGE, Mass. -- Much as an anthropologist can study populations of people to learn about their physical attributes, their environs and social structures, some marine microbiologists read the genome of microbes to glean information about the microbes themselves, their environments and lifestyles.
Using a relatively new methodology called comparative population genomics, these scientists compare the entire genomes of different populations of the same microbe to see which genes are "housekeeping" or core genes essential to all populations and which are population-specific. ...
Comprehensive new guidelines from the Osteoporosis Canada aimed at preventing fragility fractures in women and men over the age of 50 are published in CMAJ (Canadian Medical Association Journal) (pre-embargo link only) http://www.cmaj.ca/embargo/cmaj100771.pdf.
"Fragility fractures, the consequence of osteoporosis, are responsible for excess mortality, morbidity, chronic pain, institutionalization and economic costs," writes Dr. Alexandra Papaioannou, McMaster University and Hamilton Health Sciences with coauthors. "They represent 80% of all fractures in menopausal women ...
Hospital patients admitted with malnutrition or who don't eat for several days are at greater risk of a prolonged hospital stay, according to a study published in CMAJ (Canadian Medical Association Journal) (pre-embargo link only) http://www.cmaj.ca/embargo/cmaj091977.pdf.
The study, by Italian researchers, involved 1274 adults admitted to hospital for medical or surgical treatment. Patients who were bedridden, admitted for same-day surgery or procedure, or admitted for palliative care were excluded. Fifty-two patients died in hospital and 149 patients stayed less than ...
Having a family history of breast cancer can lead some people to wonder if their risk is out of their control. However, a study of more than 85,000 postmenopausal women observed that regular physical activity, maintaining a healthy weight, and drinking less alcohol lowers breast cancer risk for women with, and without a family history of the disease.
The University of Rochester Medical Center study, published online Oct. 12, 2010, by the journal Breast Cancer Research, is good news for women who have a close relative with breast cancer and thus fear that no matter what ...
Many countries now acknowledge the need to obtain their energy supply from renewable sources such as biomass. Prof. Verstraete will explain how his team have developed a new anaerobic digestion reactor which can generate as much electricity as 25 wind turbines. These reactors use a consortium of methanogenic (methane-producing) bacteria to degrade waste and energy crops to produce biogas (a mixture of methane and carbon) which is then converted to electricity using a turbine.
We were reminded of the threat of pandemic infectious disease with the swine flu (Influenza ...
