STUDY: Being Overweight A Risk
JOURNAL: JAMA 2003;289:1799-1804.
AUTHORS: Dr. Katherine Esposito
ABSTRACT: Vascular inflammation markers and insulin resistance improve in obese women after weight loss and lifestyle changes.
COMMENTARY: Elevated levels of proinflammatory cytokines have been associated with indicators of elevated body fat and with cardiovascular disease risk factors.
Obesity itself is an independent risk factor for cardiovascular disease.
Dr. Katherine Esposito and associates from Second University of Naples, Italy measured markers of vascular inflammation and insulin resistance in 120 premenopausal obese women randomly assigned to a program of lifestyle changes designed to provide sustained weight loss.
Prior to the intervention, the obese women had higher levels of serum IL-6, IL-18, and C-reactive protein, as well as higher body-mass indices, insulin resistance, and free fatty acids, compared with nonobese women, the report indicates.
After 2 years of lifestyle change, the authors report, body weight, body-mass index, waist-hip ratio, insulin resistance, blood pressure, and free fatty acid levels had all declined to a greater extent than in the control group.
Serum levels of IL-1, IL-18, and C-reactive protein were significantly reduced in the intervention group compared with controls, the results indicate, while serum levels of adiponectin (a hormone that enhances insulin action) were significantly higher.
Cytokine and C-reactive protein declines correlated with the reduction in body-mass index, while free fatty acid, IL-6, and adiponectin were independent predictors of insulin resistance.
A multidisciplinary program aimed to reduce body weight in obese women through lifestyle changes, including a low-energy Mediterranean-type diet and increased exercise, is feasible and gives sustained results over 2 years, as indicated by the significant reduction of markers of inflammation and improved insulin sensitivity.
The effective prevention of many diseases, including obesity and type 2 diabetes, starts at table with a Mediterranean-type diet and continues with physical activity.
"Although not easy to implement, this strategy will allow us to enjoy the spectacular increase in life expectancy we have experienced in the last century. It is time to move towards a more integrated approach for a large-scale control of obesity, based on lifestyle changes."
"Since both obesity and diabetes are two major risk factors for cardiovascular disease, it is reasonable to hypothesize that any intervention aimed at reducing the prevalence of these two conditions in the population will lead to a decrease of the level of cardiovascular risk," Dr. Esposito concluded.
JOURNAL: Experimental Biology Conference
AUTHORS: Dr. Fred D. Finkelman
ABSTRACT: As many asthmatics know, a blast of diesel exhaust can trigger bouts of wheezing, coughing and other asthma symptoms. Now researchers say they have figured out why these fumes are so tough on those afflicted with the illness.
COMMENTARY: The fine particles in diesel exhaust hit the human immune system with a double whammy, upping the production of an immune protein that triggers asthma attacks while suppressing a second protein that might otherwise bring symptoms to a halt.
Numerous studies have found that individuals living in urban areas or near busy highways are at much higher risk for asthma and other allergies compared with those living in less congested locales. While most experts have suspected diesel fumes as the prime culprit, until now the exact mechanism by which truck exhaust aggravates the immune system has remained unclear.
In their study, Finkelman and his colleagues injected small amounts of diesel exhaust particles into the bloodstreams of mice. The investigators found that, after injection, the mice secreted abnormally high levels of interleukin-6 (IL-6), an immune system protein "released by cells of the immune system in response to substances such as bacteria and viruses that the immune system perceives as dangerous." In the asthmatic lung, this response can go overboard, triggering airway constriction, coughing and congestion.
Luckily, the immune system has a kind of countering mechanism, a protein called interferon-gamma. When released in large quantities, interferon-gamma works to put the brakes on runaway immune responses.
Diesel exhaust appears to dampen interferon-gamma production--giving IL-6 free reign to trigger asthmatic symptoms.
STUDY: Study suggests older remedy may trump new medicines
JOURNAL: Journal of the American Medical Association
AUTHORS: Dr. Jackson T. Wright Jr.
ABSTRACT: An old-fashioned diuretic is as good, if not better, than some newer, more expensive medicines for treating high blood pressure and preventing its complications.
COMMENTARY: Diuretics, commonly called water pills, should be the first medicine prescribed to treat high blood pressure and that, when multiple medications are needed, a diuretic be one of them.
Diuretics, which work by ridding the body of excess sodium and water, have long been used as a standard blood pressure medicine.
The study compared the generic diuretic chlorthalidone with two newer, more expensive blood pressure treatments, the ACE inhibitor lisinopril and the calcium channel blocker amlodipine.
The findings show a slightly greater percentage of patients got their blood pressure below 140/90, which was the goal of the study, when they used the diuretic compared to the two newer medicines.
Researchers also found the diuretic was better than the calcium channel blocker in preventing heart failure and better than the ACE inhibitor in preventing stroke, heart failure and chest pains.
A third blood pressure drug, the alpha blocker doxazosin, was dropped from the study more than two years ago because it proved significantly less effective than diuretic treatment
JOURNAL: Iowa Women's Health Study
AUTHORS: Dr. Paul Limburg
ABSTRACT: Among postmenopausal women, excess body weight is a statistically significant risk factor for the development of colorectal cancer.
COMMENTARY: There have been consistent observational data that have suggested high body mass index is a risk factor for colon and rectal cancer among men and also among women at younger age. But excess body weight is a controversial risk factor for colorectal cancer among postmenopausal women.
Dr. Paul Limburg of the University of Minnesota in Minneapolis and colleagues assessed excess body weight, defined as a BMI > 25, as a predictor of incident colorectal cancer among 35,354 women in the prospective Iowa Women's Health Study.
During roughly a 12-year period, 988 women developed colorectal cancer. For women with excess body weight at baseline, at age 18, 30, and at menopause, the adjusted relative risk of colorectal cancer was 1.32, 1.37, 1.39, and 1.40, respectively.
The risk of colorectal cancer was attenuated among women with a history of excess body weight but no excess body weight at baseline. This suggests that weight loss may help reduce the risk of colorectal cancer.
STUDY: Get Moving
JOURNAL: Arterioscler Thromb Vasc Biol 2002;22:1869-1876.
AUTHORS: Dr. Timothy S. Church
ABSTRACT: Exercise is inversely associated with levels of C-reactive protein (CRP), an inflammatory marker directly related to coronary heart disease risk.
COMMENTARY: The investigators found that men who were the most fit tended to have the lowest CRP levels, while those deemed the least fit had the highest levels. The relationship between CRP levels and exercise remained even after adjusting for age and obesity.
Specifically, the authors discovered that people who were in the second-to-lowest category of fitness were 57% less likely to have elevated CRP levels compared with those in the least fit group.
The risk of elevated CRP decreased incrementally with increasing fitness, with most fit subjects being 83% less likely to have elevated CRP levels than least fit subjects.
The relationship between CRP levels and physical activity in women is probably similar to that in men, but more complicated due to the hormonal changes that occur during menopause.