Calcium has no effect on weight, study shows

The notion that calcium supplements can prevent weight gain has gotten a fair amount of attention and some support in medical studies, so researchers at the National Institutes of Health designed what they believe is the first large, randomized investigation specifically to test the idea.

The supplements made no difference.

The researchers divided 340 overweight and obese adults, more than two-thirds of them women, into two groups of equal size. One group took 1,500 milligrams of calcium carbonate with meals daily. The other took a placebo. They visited the clinic every six months and filled out questionnaires every three months.

After two years, the average difference in weight gain between the groups was less than one ounce; other fat-related measures were the same as well. Sex and race made no difference. Nor did concentrations of Vitamin D, which helps metabolize calcium.

"In summary," the authors write in the current issue of the Annals of Internal Medicine, calcium supplements "did not substantially alter weight or fat gain over 2 years in overweight and obese adults."

- Don Sapatkin

Pesticide exposure doubles risk of a blood condition

A study of 678 people who regularly apply pesticides, drawn from a U.S. Agricultural Health Study of more than 50,000 farmers, has found that exposure to certain pesticides more than doubles one's risk of developing an abnormal, precancerous blood condition.

The condition, called MGUS (monoclonal gammopathy of undetermined significance), is characterized by an abnormal level of a plasma protein. It can lead to multiple myeloma, a painful cancer of the plasma cells in the bone marrow.

Previously, inconclusive evidence linked agricultural work to an increased multiple myeloma risk. "Our study is the first to show an association between pesticide exposure and an excess prevalence of MGUS," said lead author Ola Landgren, of the National Cancer Institute. The findings are published in the current issue of Blood, the official journal of the American Society of Hematology.

Among the chemicals studied, dieldrin (an insecticide), carbon-tetrachloride/carbon disulfide (a fumigant mixture), and chlorothalonil (a fungicide) were associated with a significantly increased risk of MGUS. It increased 5.6-fold, 3.9-fold, and 2.4-fold, respectively. Several other insecticides, herbicides, and fungicides were associated with MGUS, but not significantly.

- Sandy Bauers

Frequent snoring in pregnancy linked to gestational diabetes

A small study suggests that women who frequently snore during pregnancy are more likely to develop gestational diabetes than silent sleepers.

For the Northwestern University study, 189 women completed a sleep survey in the first half of pregnancy and during the final 12 weeks. Those who reported snoring at least three times a week - as about 30 women did - had a 14 percent chance of gestational diabetes, compared with 3 percent for non-snorers.

Snoring may be triggered by pregnancy weight gain that constricts airways, but how the sleep disorder might be linked to diabetes is unclear.

About 4 percent of pregnant women develop gestational diabetes, characterized by high blood sugar levels. This can cause fetuses to grow overly large, which can complicate childbirth.

The study, presented last week at the annual meeting of the Associated Professional Sleep Societies, concluded that more research is needed to understand the finding and to suggest treatment for snorers.

- Marie McCullough

Type of antidepressant may damage sperm's DNA

Studies have shown that a class of antidepressant medication can weaken erectile function. Now, a new study in the journal Fertility and Sterility finds that these "selective serotonin reuptake inhibitors" also may damage the sperm's DNA.

The authors studied just one type of SSRI - paroxetine - because it has been shown to have the biggest effect in delaying ejaculation.

The drug was given to 35 adult male volunteers for five weeks and measured the level of DNA fragmentation before, during, and after drug treatment. Before the drug, about 10 percent of patients had abnormal levels of fragmentation, whereas half of them did so at week four.

The measurements returned to normal one month after the drug was stopped, according to the researchers, from Weill Cornell Medical College and Harvard Medical School. They suspect that the DNA became damaged because the drug seemed to slow down the sperm, allowing it to age. The authors said patients hoping to conceive should ask their physicians about alternative treatments for depression.

- Tom Avril