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[check mark] Sleep Disordered Breathing and Obesity


[check mark] Low BMD for Leukemia Survivors?


[check mark] Multivitamins May Not Prevent Cancer or Heart Disease


Growth Hormone Treatment After Weight Loss Surgery Prevents Loss of Muscle Mass

Growth hormone treatment for 6 months after weight loss surgery reduces patients' losses in lean body mass and skeletal muscle mass, according to a new study. The study investigated whether growth hormone treatment could prevent or reduce these losses. The researchers evaluated women who underwent laparoscopic-adjustable silicone gastric banding surgery and were diagnosed with growth hormone deficiency after the procedure. These women were divided into 2 groups. Both groups participated in a standardized diet and exercise program, but only 1 group also received growth hormone. After a follow-up period of 6 months, women receiving growth hormone experienced a significant decrease of fat mass and an increase in lean body and skeletal muscle mass. The results show that the use of short-term treatment with growth hormone during a standardized program of low-calorie diet and physical exercise is effective in reducing the loss of muscle mass and increasing the loss of fat mass after bariatric surgery.


Source: Journal of Clinical Endocrinology and Metabolism.


Multivitamins Not Associated With Cancer, Heart Disease, or Death in Women

Postmenopausal women who take multivitamins seem to have the same risk of most common cancers, cardiovascular disease, or dying of any cause as women who do not take multivitamin supplements. About half of Americans use dietary supplements, spending more than $20 billion per year on these products, according to background information in the article. Scientific data supporting the benefits of supplements-including multivitamins, the most commonly used supplements-are lacking for many indications.


The researchers analyzed data from participants in the Women's Health Initiative: 161,808 women from 3 clinical trials testing hormone therapy, dietary modification, and vitamin D supplements and 93,676 women who were part of an observational study. The women enrolled in the Women's Health Initiative between 1993 and 1998; information about vitamin use was collected through interviews and by supplement bottles brought to clinic visits.


A total of 42% of the participants used multivitamins. Through 2005 (a median or midpoint of 8 years of follow-up for the clinical trials and 7.9 years for the observational study), 9,619 cases of breast, colorectal, endometrial, renal, bladder, stomach, lung, or ovarian cancer developed; 8,751 cardiovascular events, such as heart attack and stroke, occurred; and 9,865 deaths were reported. Analyses revealed no significant associations between multivitamin use and the likelihood of developing cancer or cardiovascular disease, or of dying.


The results suggest that multivitamin use does not confer meaningful benefit or harm in relation to cancer or cardiovascular disease risk in postmenopausal women. The authors conclude that "Nutritional efforts should remain a principal focus of chronic disease prevention, but without definitive results from a randomized controlled trial, multivitamin supplements will not likely play a major role in such prevention efforts."


Source: Archives of Internal Medicine


Sleep Disordered Breathing and Obesity: Independent Effects, Independent Causes

A study addressing the issue of insulin sensitivity with respect to sleep disordered breathing (SDB) examined the relationship between SDB and insulin resistance and linked it to pre-diabetic changes in insulin production and glucose metabolism.


The researchers used dual-energy x-ray absorptiometry, a highly precise technique for assessing body fat, and frequently sampled intravenous glucose tolerance test, which provides a detailed picture of the subject's insulin sensitivity over time rather than a simple snapshot at a specific moment. They recruited 118 subjects: 39 who had no SDB and 79 who were newly diagnosed with SDB but who had not been treated. Each subject underwent a sleep study to assess his/her level of SDB and then underwent the special glucose tolerance test to study his/her glucose metabolism and insulin sensitivity/production the following day. The major finding was that SDB was strongly associated with a decrease in the 3 major metabolic pathways that the body uses to metabolize glucose-insulin sensitivity, glucose effectiveness, and pancreatic cell function-independent of adiposity and is characterized by multiple physiological deficits that increase the predisposition for type 2 diabetes mellitus.


Source: American Journal of Respiratory and Critical Care Medicine


Adult Survivors of Childhood Leukemia Have Lower Bone Mineral Density

Men who survived childhood leukemia treatment into adulthood were more likely to have low bone mineral density than other adults their age, putting them at risk of osteoporosis and bone fractures, according to a new study.


The study found that 24% of the 74 survivors studied had abnormally low bone mineral density, a measure of the strength of bones. The average age of the survivors was 30 years, and they had been treated an average of 24 years ago for the most common type of childhood cancer, acute lymphoblastic leukemia.


According to the World Health Organization, 11% of 30-year-old men and 19% of 30-year-old women, on average, have low bone mineral density, a condition known as osteopenia. In this study, 36% of men and 16% of women had low bone mineral density. The male survivors were more likely than female survivors to have lower bone mineral density, and shorter men and women were also more likely to have weaker bones.


Growth hormones are known to be affected by leukemia treatment. Low growth hormone levels and low levels of another hormone called insulinlike growth factor 1 can contribute to poor bone health, but they are not the only factors involved. The researchers believe the disease itself or the treatments such as radiation-particularly radiation to the brain-and chemotherapy may affect bone growth. What remains to be determined is if providing extra calcium or other nutritional treatments can ameliorate the low bone density.


Source: Cancer


Phosphorus-Lowering Drugs Linked to Lower Mortality in Dialysis Patients

For patients on dialysis, taking medications to reduce levels of the mineral phosphorus in the blood may reduce the risk of death by 25% to 30%. The drugs, called phosphorus binders, were associated with improved survival in new dialysis patients, including those patients with only modest or even no increase in their blood phosphorus levels. The researchers compared mortality rates in 2 groups of dialysis patients: 3,555 patients who started treatment with phosphorus binders during the first 90 days after starting dialysis and 5,055 who did not receive phosphorus-lowering treatment during the same period. During the first year on dialysis, patients treated with phosphorus binders had a significantly lower risk of death-30% lower, after adjustment for other risk factors.


A further analysis compared mortality rates in a large subgroup of treated and untreated patients, who were closely matched in terms of their initial blood phosphorus levels and their likelihood of receiving phosphorus-lowering treatment. In this "propensity score-matched" analysis, risk of death was 25% lower in patients treated with phosphorus binders. The protective effect of phosphorus binders was smaller, but still significant, in an analysis that excluded patients who died in the first 90 days on dialysis.


High blood phosphorus levels (hyperphosphatemia) are common in patients with kidney disease. Hyperphosphatemia is a risk factor for death; phosphorus binders are widely prescribed to dialysis patients. However, these recommendations are based largely on opinion. The new results provide an important missing piece of information by showing a lower risk of death in dialysis patients receiving phosphorus binders. If phosphorus binders improve survival even in new dialysis patients with relatively normal phosphorus levels, then it is possible that they might also be beneficial for the much larger group of patients with less-advanced kidney disease.


The study has some important limitations. Because it was not a randomized trial, it is prone to certain forms of bias and confounding. Other limitations include the limited (1 year) follow-up and the lack of data on patients' dietary phosphorus intake and whether they actually took their prescribed phosphorus binders.


Source: Journal of the American Society of Nephrology