Archive for July, 2010
The typical Western diet is associated with an increased risk for the metabolic syndrome compared with other major dietary patterns, a cross-sectional study has found.
Iranian researchers led by Maryam Zare (Isfahan University of Medical Sciences) hypothesized that major dietary patterns would be associated with the prevalence of components of the metabolic syndrome.
To investigate, they enrolled 425 adults aged 35–55 years and studied their diets using food-frequency questionnaires.
Writing in the journal Nutrition, Zare et al say they observed five major dietary patterns, which they labeled “Western,” “prudent,” “vegetarian,” “high-fat dairy,” and “chicken and plant.”
They then used multivariate analysis to look for associations between each dietary pattern and five components of the metabolic syndrome.
The Western diet – high in sweets, butter, soda, mayonnaise, sugar, cookies, lamb, hydrogenated fat, and eggs – was associated with an increased risk for elevated serum triglyceride levels (odds ratio [OR]=1.76) and elevated blood pressure (OR=2.62).
The prudent diet – high in fish, peas, honey, nuts, juice, dry fruits, vegetable oil, liver and organic meat, and coconuts, and low in hydrogenated fat and non-leafy vegetables – was associated with a reduced risk for low levels of high-density lipoprotein cholesterol (OR=0.55).
And finally, the vegetarian diet – high in potatoes, legumes, fruits rich in vitamin C, rice, green leafy vegetables, and fruits rich in vitamin A – was associated with an increased risk for high plasma glucose (OR=2.26).
The remaining two dietary patterns – high-fat dairy (high in high-fat yogurt and high-fat milk and low in low-fat yogurt, peas, and bread), and chicken and plant (high in chicken, fruits rich in vitamin A, green leafy vegetables, and mayonnaise and low in beef, liver, and organic meat) – were not associated with significantly increased or reduced risks for any component of the metabolic syndrome.
In a separate analysis, the team confirmed that the Western diet was associated with an increased risk for the metabolic syndrome (OR=2.32) and the prudent pattern with a reduced risk (OR=0.58), after adjusting for confounders.
“Our findings suggest that consumption of a Western dietary pattern promotes the risk of the metabolic syndrome,” the authors conclude.
“Factors can markedly influence dietary intakes, such as differences in culture, ethnicity, religion, availability of specific foods, and economic development, among others. Therefore, further studies are required to identify major dietary patterns across the country and search for their possible associations with chronic diseases.”
Sensor-augmented insulin pump therapy achieves significantly better glycemic control in patients with Type 1 diabetes than multiple insulin injections, show results from the STAR 3 study.
The Sensor-Augmented Pump Therapy for A1C Reduction (STAR) 3 study was set up to evaluate the use of a continuous glucose monitor combined with a glucose pump, compared with standard injection therapy in 485 Type 1 diabetics (329 adults, 156 children) with poor glycemic control over a period of 1 year.
Richard Bergenstal (International Diabetes Center at Park Nicollet, Minneapolis, Minnesota, USA) and team report that at study completion, mean glycated hemoglobin (HbA1c) – 8.3% in both groups at baseline – had decreased significantly to 7.5% in the insulin pump group versus 8.1% in the multiple injections group.
In addition, 27% of patients in the insulin pump group achieved their target HbA1c of below 7% compared with only 10% of the multiple injection group.
Rates of severe hypoglycemia were similar in both groups at 13.31 and 13.48 cases per 100 person-years, respectively, in the insulin pump and multiple injection groups. No significant weight gain was observed in either group.
In an accompanying editorial, Howard Wolpert (Joslin Diabetes Center, Boston, Massachusetts, USA) commented: “The STAR 3 study and other randomized trials have shown that continuous glucose monitoring can take the management of Type 1 diabetes to a new level: improved glycemic control without an associated increase in hypoglycemia.”
He said: “The focus now has to move on to translating this evidence into effective practice so that the broader population of patients with Type 1 diabetes can realize these benefits.”
Results from an influenza surveillance project in Canada show that patients with diabetes who become infected with the pandemic influenza A (H1N1) virus are at significantly greater risk for hospitalization and intensive care unit (ICU) admission than those without diabetes.
Diabetes is thought to be a risk factor for more severe flu infection, but attempts to quantify such increased risk have revealed differing results.
Robert Allard (University of Montreal) and colleagues reported outcomes of their study of 162 patients, aged 28.6 years on average, who were hospitalized with polymerase chain reaction-confirmed pandemic H1N1 infection. Of these, 22 (14%) had diabetes – nine had Type 1 and 13 had Type 2.
The number of patients with diabetes was significantly higher than the 7.1 cases that would be expected from population rates, and the team found that the presence of either type of diabetes increased the risk for hospitalization with pandemic H1N1 infection around three fold compared with not having diabetes.
In addition, 32.3% (n=10) of the 31 patients with pandemic H1N1 infection who required admission to the ICU after hospital admission were diabetic.
The researchers calculated that diabetics had a significant 4.29-fold increased risk for ICU admission with pandemic H1N1 infection following adjustment for age and presence of cardiovascular disease compared with nondiabetics. The degree of risk was not significantly different between those with Type 1 and Type 2 diabetes.
The percentage of hospitalized patients with diabetes in this study was similar to that of previous studies in which 11–21% of hospitalized patients with pandemic H1N1 infection were reported to be diabetic.
“Our results corroborated the impression that persons with diabetes who contract pandemic H1N1 are more likely than others to be hospitalized or to require ICU care,” add Allard and team in the journal Diabetes Care.
“As previously reported for infection-related mortality in diabetic patients, ICU risk was independent of the presence of coexisting heart disease.”
Both all-cause and cardiovascular mortality are substantially increased in people with Type 2 diabetes compared with nondiabetics, UK researchers have shown.
They also demonstrate that duration of diabetes is an independent predictor for mortality risk and that younger women with the disease are at disproportionately increased risk for cardiovascular mortality.
Josie Evans (University of Stirling) and colleagues used record-linkage databases to identify 10,532 patients diagnosed with diabetes between 1993 and 2004. They also identified a control cohort of 21,056 nondiabetic individuals from general practice.
All patients were followed-up for a maximum of 12 years for mortality. During this time, 17.7% of diabetes patients and 14.1% of controls died. The main causes of death were diseases of the circulatory system (44.9% and 39.3%) and neoplasms (25.3% and 27.7%) for diabetic and nondiabetic participants, respectively.
The researchers calculated absolute mortality rates for subgroups of participants stratified by gender and age decile.
In all subgroups, rates of all-cause and cardiovascular mortality were “clearly” higher in diabetes patients versus controls. Similarly, all rates were higher for males than females, except for all-cause mortality in patients aged over 75 years.
Interestingly, the difference in absolute rates of all-cause mortality appeared to widen slightly among females and narrow slightly among males with increasing age. Also, widening of the absolute rates of cardiovascular mortality between diabetic and nondiabetic participants appeared to occur slightly earlier among women than men.
Further analyses revealed that the risk for all-cause mortality increased with increasing duration of diabetes, reaching a peak between 6 and 9 years, then decreased. This pattern was even more marked for cardiovascular mortality but peaked slightly earlier.
Writing in the journal Diabetic Medicine, Evans et al remark: “This study further supports the literature showing that Type 2 diabetes reduces life expectancy.”
Patients with diabetes mellitus who drink moderate amounts of alcohol are not at an increased risk for developing retinopathy, but are at an increased risk for losing visual acuity, research shows.
“The relationship with the decline in visual acuity was continuous through the distribution of alcohol consumption,” report Joline Beulens (University Medical Centre, Utrecht, The Netherlands) and colleagues in the journal Diabetic Medicine.
There are limited data to date on the association between alcohol consumption and diabetes mellitus, but lifestyle factors, including alcohol consumption, can increase the risk for developing microvascular complications.
The researchers also note that alcohol is toxic to neurological tissues, including the retina, and heavy drinking might cause oxidative stress in these tissues and impair vision.
In this study, the group analyzed data on 1239 individuals aged 55 to 81 years with Type 2 diabetes previously enrolled in the AdRem study, a sub-study of the Action in Diabetes and Vascular Disease: Preterax and Diamicron MR Controlled Evaluation (ADVANCE) trial.
Alcohol consumption was self-reported, with moderate drinking defined as one to 14 drinks per week and heavy drinking defined as more than 14 drinks weekly.
After a mean follow-up of 5.5 years, 182 individuals were diagnosed with diabetic retinopathy, while 640 had retinal vascular lesions, and 693 had declines in visual acuity.
In a logistic regression model, moderate or heavy consumption of alcohol, compared with no drinking, was not associated with the presence or progression of diabetic retinopathy.
Regarding visual acuity, after adjusting for potential confounders, moderate and heavy alcohol consumption was associated with an approximate two-fold increase in risk. For moderate drinking, compared with no drinking, the odds ratio was 1.83, while for heavy drinkers, the odds ratio was 2.09.
“When modeling alcohol consumption as a continuous variable, we observed a 2% increase in the risk of deterioration of visual acuity for each additional alcoholic drink consumed per week,” report Beulens and colleagues.
No type of alcoholic beverage was worse than any other, although the magnitude of association was slightly increased with beer compared with wine, they add.
The benefits of intensively modifying risk factors for cardiovascular disease (CVD) vary widely in people with diabetes, researchers claim.
Their study revealed that patients at the highest CVD risk may account for nearly all the benefits of treating to target levels of low-density lipoprotein (LDL) cholesterol and blood pressure.
In contrast, they report that patients who were at average risk – comprising nearly three-quarters of the population – received “very little benefit.”
The findings lead the investigators to recommend tailoring treatment for individual patients based on the expected benefit of intensifying treatment.
And they go even further to warn: “Current treatment approaches that encourage uniformly lowering risk factors to common target levels can be both inefficient and cause unnecessary harm.”
The team developed a simulation model for a treat-to-target strategy with goals of 100 mg/dl (2.59 mmol/l) for LDL cholesterol and 130/80 mmHg for blood pressure using risk factor reductions obtained in clinical trials.
This was applied to several million individuals aged 30 to 75 years with diabetes who participated in the US National Health and Nutrition Examination Survey III. Patients received up to five titrations of statin therapy and eight of antihypertensive therapy.
Treating to targets resulted in a gain of 1.50 quality-adjusted life-years (QALYs) of lifetime treatment-related benefit for LDL cholesterol and 1.35 QALYs for blood pressure.
This declined to 1.42 and 1.16 QALYs, respectively, after accounting for treatment-related harms.
Most of the benefit was limited to the first few steps of intensifying medication or to tight control for a limited group of high-risk patients, Justin Timbie (RAND Health, Arlington, Virginia, USA) and co-workers report.
Indeed, they say that intensifying treatment beyond the first step for LDL cholesterol or the third step for blood pressure resulted in limited benefits or net harm for patients at below-average risk.
Reporting in the Archives of Internal Medicine, the researchers say most primary prevention guidelines are moving more strongly than those for diabetes toward basing recommendations on an individual patient’s calculated CVD risk.
There is a strong association between the metabolic syndrome and microvascular disease in people with Type 2 diabetes, Belgian researchers have shown.
Their analysis, which appears in the journal Diabetes & Metabolic Syndrome: Clinical Research & Reviews, suggests that the risk for microvascular complications increases in line with both the presence and severity of the syndrome.
Michel Hermans (Université catholique de Louvain, Brussels) and team studied 738 adults with Type 2 diabetes, of whom 145 had the metabolic syndrome. Participants with and without the syndrome were well-matched with respect to age and diabetes duration.
The mean number of components of the metabolic syndrome was 1.8 in those without the syndrome versus 4.0 in those with.
Body mass index, waist circumference, relative/absolute fat mass, visceral fat, conicity, insulin resistance, triglycerides, glycated hemoglobin, systolic blood pressure, and inflammatory markers were all significantly higher in those with versus without the metabolic syndrome.
With regard to macrovascular disease, the prevalence of peripheral artery disease, coronary artery disease, and cerebrovascular disease were all higher in those with the syndrome than without, at 11 vs 7%, 26 vs 10%, and 8 vs 5%, respectively.
Furthermore, the prevalence of microvascular complications increased with increasing number of components of the metabolic syndrome.
Specifically, diabetic retinopathy affected 3% of those with one component versus 26% of those with five components. For peripheral neuropathy the values were 19% and 35%, respectively, while for albuminuria the values were 6% and 32%, respectively.
Discussing their results, Hermans and co-authors note that the association with macrovascular disease is expected “as intrinsic to the current definition of metabolic syndrome.”
By contrast, “it is much debated whether establishing the presence of a metabolic syndrome in hyperglycemic states further contributes to stratifying or predicting microvascular risk.”
They say their data “indicate a strong association between metabolic syndrome and vascular disease, with respect to both macro- and microangiography in a large, mostly Caucasian, cohort of Type 2 diabetes mellitus patients of both genders.”
However they add: “Whether these risks are cumulative, potentiating or permissive will be determined in prospective studies on the natural history of microvascular disease in relation with the serial acquisition of metabolic syndrome phenotype components.”