Active or Passive Smoking May Be Linked to Glucose Intolerance
on Tuesday, April 18 @ 13:54:12 CDT
Both active and passive smoking increase the risk of developing glucose intolerance, according to the results of a prospective cohort study.
"Smoking has been linked to impaired response to glucose tolerance tests and insulin resistance," write Thomas K. Houston, MD, from the Birmingham Veterans Affairs Medical Center in Alabama, and colleagues. "Although smoking cessation can result in modest weight gain, smoking is related to a more unhealthy distribution of upper body weight and greater waist:hip ratio. Smoking has also been associated with risk of chronic pancreatitis and pancreatic cancer, suggesting that tobacco smoke may be directly toxic to the pancreas."
The Coronary Artery Risk Development In young Adults (CARDIA) study began in 1985 to 1986 with recruitment of black and white men and women aged 18 to 30 years with no glucose intolerance at baseline. Participants were 1386 current smokers, 621 previous smokers, 1452 never smokers with reported exposure to secondhand smoke and 1113 never smokers with no exposure to secondhand smoke. The primary endpoint was time to development of glucose intolerance (glucose, >/= 100 mg/dL or taking antidiabetic drugs) during 15 years of follow-up.
At baseline, median age was 25 years, 55% of participants were women, and 50% were African American. During follow-up, glucose intolerance developed in 16.7% of participants. There was a graded association between smoking exposure and the incidence of glucose intolerance during the 15-year follow-up, which was 21.8% for smokers, 17.2% for never smokers with passive smoke exposure, 14.4% for previous smokers, and 11.5% for never smokers with no passive smoke exposure.
After adjustment for multiple baseline sociodemographic, biological, and behavioral factors, risk was still higher in current smokers (hazard ratio [HR], 1.65, 95% confidence interval [CI], 1.27 - 2.13) and never smokers with passive smoke exposure (HR, 1.35; 95% CI, 1.06 - 1.71) than in never smokers without passive smoke exposure. However, risk in previous smokers was similar to that in never smokers without passive smoke exposure.
"We found that tobacco exposure is associated with the development of glucose intolerance over a 15 year period, with a dose-response effect apparent," the authors write. "These findings support a role of both active and passive smoking in the development of glucose intolerance in young adulthood."
"Importantly, we identified passive tobacco exposure in never smokers as a new risk factor for glucose intolerance," the authors conclude. "If confirmed by further research, these findings provide further documentation of the deleterious effects of tobacco smoking, and policy makers may use them as additional justification to reduce exposure to passive smoke."
BMJ. Posted online April 6, 2006.
on Tuesday, April 18 @ 14:03:46 CDT
The results suggest that poor glycemic control, as indicated by elevated HbA1c levels in individuals with diabetes, is associated with an increased risk of PAD independently of other known risk factors.
In adult patients with diabetes, increased hemoglobin A1c (HbA1c) levels are associated with an elevated risk of peripheral arterial disease.
Dr. Elizabeth Selvin from Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland stated that, "This study is one of the first prospective studies to examine the association of HbA1c and the development of peripheral arterial disease (PAD) in diabetics looking specifically at different manifestations of PAD.” Dr. Selvin and colleagues used data from The Atherosclerosis Risk in Communities study to investigate whether HbA1c is related to PAD in 1,894 middle-aged adults with diabetes.
The risk of hospitalization related to PAD increased with increasing tertiles of HbA1c level, the authors report, as did the risk of intermittent claudication.
Specifically, patients in the second and third tertiles of HbA1c level were 53% and 64% more likely, respectively, than those with the lowest HbA1c to have PAD, as defined solely on the basis of a low ankle-brachial index (ABI below 0.9), the results indicate.
The researchers note that trends toward higher risk of PAD with higher HbA1c level were evident for all manifestations of PAD, regardless of whether or not diabetes had been diagnosed.
Fasting blood glucose levels were also associated with the risk of PAD, the report indicates, but the association was much weaker than that observed for HbA1c level.
"Our results suggest that poor glycemic control, as indicated by elevated HbA1c levels in individuals with diabetes, is associated with an increased risk of PAD independently of other known risk factors," Dr. Selvin concluded. "This association was particularly strong for the symptomatic, more severe manifestations of PAD, including intermittent claudication and PAD-related hospitalizations."
"Ultimately, our results suggest that efforts to improve glycemic control in persons with diabetes may substantially reduce the risk of PAD development," Dr. Selvin added.
Diabetes Care 2006;29:877-882.
on Tuesday, April 18 @ 13:53:17 CDT
Postprandial blood glucose is better than fasting blood glucose in predicting cardiovascular events in patients with type 2 diabetes.
Dr. Mariella Trovati from University of Turin told Diabetes In Control that, "In type 2 diabetic patients, not only fasting blood glucose and glycated hemoglobin, but also postprandial blood glucose should be measured and taken into consideration in planning the treatment,", Italy.
Dr. Trovati and colleagues investigated whether postprandial blood glucose, either after breakfast or after lunch, predicts cardiovascular events better than fasting blood glucose, and whether the relationships between blood glucose and cardiovascular events differ in 284 men and 245 women.
Blood glucose after lunch was higher than blood glucose after breakfast in men and women, the authors report, and the differences were greater in patients with cardiovascular events.
In men, a significantly increased risk of cardiovascular events was observed only for increasing levels of blood glucose after lunch.
In contrast, several blood glucose levels (fasting blood glucose, blood glucose after lunch, and blood glucose before dinner) were significantly associated with the risk for cardiovascular events in women, the researchers note.
However, the investigators note, only blood glucose after lunch remained a significant predictor in a model that included all blood glucose values.
The hazard ratio for blood glucose after lunch was significantly greater in women (5.54) than in men (2.12), the report indicates.
"At present, we are evaluating our series of patients after 10 years, to clarify whether the impact of postprandial blood glucose on cardiovascular events is still evident after such a long follow-up," Dr. Trovati said.
"The meaning of postprandial blood glucose in the clinical practice is a matter of very intense debate," the authors conclude. "Our study supports the conclusion that it should be carefully considered in type 2 diabetic patients, because it plays a relevant predictive role for cardiovascular events, especially in women."
J Clin Endocrinol Metab 2006;91:813-819.
on Tuesday, April 18 @ 13:44:18 CDT
Researchers from the University of Bristol, UK, have discovered why patients with diabetes develop a condition which leads to amputation of the lower limbs.
It is caused by an alteration in their skin tissue before leg ulcers develop.
It is not uncommon for a person with Diabetes Type 2 to develop an ulcer in the lower limb which does not heal. Eventually, the condition becomes such that the only effective treatment is to amputate below the knee.
The best way to prevent an ulcer complication is to lower the patient's blood pressure, glucose and cholesterol. The problem is the condition is often undetected at its early stages. So, effective treatment can sometimes arrive too late.
About 15% of people with diabetes who have a foot ulcer will need an amputation.
People most at risk of ulcers that lead to limb loss are those with Type 2 diabetes.
In this study, scientists examined 14 patients with diabetes who had had an amputation below the knee. Skin tissue from their two legs were compared - the leg with the amputation below the knee and the healthy leg.
They found that the leg with the amputation below the knee had problems with the connective tissue that supports the skin - the skin had changed. Tissue was being renewed at a much faster rate leading to abnormal collagen. The skin, being weaker, was breaking down faster - a condition which allows ulcers to form more easily.
Now that we know why ulcers can happen, it may become easier to find ways of offering treatments which prevent the ulcer from developing in the first place.
Understanding what happens in the tissue could allow doctors to develop treatments which prevent ulcers developing, and therefore help patients avoid amputations.
Dr. J Tarlton, lead researcher said the results of the study have opened up new avenues that previously nobody knew existed. He, and his team, believe the principles of this research could be applied to other disorders where the tissues are affected by oxygen deficiency, such as ischaemic heart disease.
Dr. Tarlton added that more research is required to understand how widespread this problem is. He believes this breakthrough will mean that ways can be found to improve the quality of a great many people's lives.
University of Bristol, UK
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on Tuesday, May 09 @ 14:55:38 CDT
Patients with Type 2 diabetes, aged 35 to 54, are three times more likely to die early than those of the same age without the disease.
The disease develops when the body can not make enough insulin or when the insulin that is produced does not work properly as compared to type 1 diabetes in which the body cannot make any insulin at all.
The study which considered 264,000 patients showed that Type 2 Diabetes was just as dangerous as the type 1 which was earlier considered more vigorous.
Research author Henrietta Mulnier of Surrey University and team compared information from GPs' records in the UK on deaths from all causes between January 1992 and October 1999.
Mulnier said that findings showed that “people with Type 2 diabetes would have a higher risk of dying earlier rather than later."
She emphasized that added that there was “need to focus on early detection and treatment.”
Published in the journal of Diabetic, May 2006
on Tuesday, May 09 @ 14:12:59 CDT
Insulin rather than salt is the major driver of hypertension, according to an analysis of data from a study.
In the study, obese patients consuming a high saturated fat diet increased daily sodium intake from less than 2 grams a day to more than 20 grams a day. But they also lost an average of 5.5 kg-or about 5% of their total body weight-in six weeks.
"At the same time there were dramatic and significant reductions in fasting insulin and in mean arterial pressure," reported James H. Hays, M.D., of the Christiana Care Health Services in Newark, Del., at the American Association of Clinical Endocrinologists meeting here today.
Dr. Hays said the finding strongly suggests that "we need to stop paying so much attention to sodium and pay much more attention to fasting insulin."
The patients in the trial were all put on a very high fat diet-50% of calories consumed came from saturated fat sources "mostly flesh of mammals," he said. And were told to avoid starch. There was, however, no caloric restriction. "These were free range humans who could consume as much as they liked," he said.
Dr. Hays and colleagues previously reported in the Mayo Clinic Proceedings that the patients achieved significant improvements in a number of cardiovascular risk factors, including reductions in total triglycerides, triglycerides, very low density lipoprotein (vLDL), and vLDL particle size. Additionally, while LDL and HDL concentrations were unchanged, there were significant increases in HDL and LDL particle size.
Among the findings reported last week:
· After six weeks, average fasting blood glucose was 98.3 mg/dL ±9.3 mg/dL down from 106.1 mg/dL ±9.3 17.7 mg/dL (P<0.05).
· At baseline, average fasting insulin was 21.3± 12.2 microunits/ml, after six weeks it declined to 14.8 mu/ml± 5.7 mu/ml (P<0.05).
· Mean arterial pressure decreased by an average of 5.5 mm Hg from 96 mm Hg at baseline to 88.5 mm Hg after six weeks of the high fat diet (P<0.05).
The patients in the study "were all very high risk at baseline and were all taking a number of medications including a number of antihypertensive drugs," he said. "By the end of the study some patients were able to stop drug therapy and others were able to reduce their doses."
Dr. Hays said it is also possible that the real key to the success of these patients is the rapid weight loss. "It all comes back to obesity," he said. Asked whether a similar weight loss achieved with a restricted calorie diet or a low fat diet could produce the same results, he agreed that it could.
Asked to explain the rapid weight loss observed in the high fat study, he said that satiety is a factor. "Steak at every meal sounds good, but it gets old."
He said, however, that although he was once "pretty close to a vegetarian, I do believe in this diet (high fat, red meat) and I do follow it myself."
Abdul-Rahman, M et al "A High-Fat Diet in Obese Patients Induces Weight Loss, Leads to Improved Insulin Resistance, and Lowers Systolic Blood Pressure Despite Marked Increase in Dietary Sodium Intake" Abstract 201 Endocr Pract 2006 12
on Tuesday, February 06 @ 21:21:32 CST
“When malnutrition occurs to women of childbearing age, their offspring will inherit abnormal mitochondrion.”
A research team at the Korea Cancer Center Hospital, including Lee Yoon-yong and professors of the Seoul National University College of Medicine Lee Hong-gyu and Park Kyung-su, reported, “When malnutrition occurs to women of childbearing age, their offspring will inherit abnormal mitochondrion.” Mitochondrion is an apparatus within a cell that creates energy. A child inherits nearly all mitochondrion from his or her mother.
The research team kept feeding low-protein feed to pregnant lab rats from the beginning of gestation to birth and breast-feeding stages. This fodder contained three times less the amount of protein in ordinary feed.
The young rats were born 20 percent underweight due to malnourishment. Even after weaning and consuming solid food, the rats did not gain weight. After 20 weeks, the team removed the pancreas of the rats and examined them through a microscope. In terms of human age, rats aged 20 weeks are in their twenties to thirties.
The results showed that the size of their beta cells that secreted insulin were dramatically smaller and scarcer than normal. The mitochondrion in their beta cells were reduced and were contorted into extended shapes. The team concluded that the offspring of the female rat inherited its mitochondrion from its malnourished mother.
The professor said, “When there’s a problem with the mitochondrion, the insulin secreted from the pancreas that breaks down glucose decreases, limiting the function of insulin in the liver or muscles and bringing on diabetes or obesity. This is the reason why malnourished female North Korean defectors get overweight in South Korea.” The nutrients accumulate in the body because they are decomposed and cannot be used for activity.
The study results presented on February 2-3 at the “Fourth Asian Society for Mitochondrial Research and Medicine” to be held at the Seoul National University Hospital.
Oral Insulin To Prevent Type 1 Diabetes Tested In Study: Researchers have begun a clinical study of oral insulin to prevent or delay type 1 diabetes in at-risk people, in more than 100 medical centers across the United States, Canada, Europe, and Australia. “Our goal is to prevent type 1 diabetes or to delay it as long as possible. If diabetes can be delayed, even for several years, those at risk will be spared the difficult challenges of controlling glucose and the development of complications for that much longer,” said TrialNet study chair Jay Skyler, M.D., of the University of Miami. In the study, researchers are testing whether an insulin capsule taken by mouth once a day can prevent or delay diabetes in a specific group of people at risk for type 1 diabetes. An earlier trial suggested that oral insulin might delay type 1 diabetes for about four years in some people with autoantibodies to insulin in their blood. Animal studies have also suggested that insulin taken orally may prevent type 1 diabetes. Some scientists think that introducing insulin via the digestive tract induces tolerance, or a quieting of the immune system. Insulin taken orally has no side effects because the digestive system breaks it down quickly. To lower blood glucose, insulin must be injected or administered by an insulin pump. NIH/National Institute of Diabetes and Digestive and Kidney Diseases Feb. 2007