The Brazilian supermodel and wife of New England Patriot quarterback Tom Brady caused a stir recently when she called for a global law mandating that babies be breast-fed for six months, irking women who weren’t able to breast-feed or chose not to. But the number of breast-fed babies in her adopted home state is above the national average.

More than three out of every four babies born in Massachusetts begin breast-feeding at birth, and half are still breast-feeding at 6 months old, placing the state just above the national average, according to a government report released last week. At 12 months old, Massachusetts babies are also above the national average, but both state and national levels fall below a target of 1 out of 4 babies continuing to breast-feed for one year.

Helping women breast-feed their babies from birth and throughout their first year of life is a policy goal of the US Centers for Disease Control and Prevention, which issued the report card. State rates ranged from a high of 90 percent of babies starting life breast-feeding in Utah to a low of 53 percent in Mississippi. Last week’s report reflects data gathered in 2007.

Oregon leads with 62 percent of babies breast-feeding at 6 months and is tied with Vermont with 40 percent of babies breast-feeding at 12 months. Louisiana was lowest at 6 months, with 20 percent of babies being breast-fed, and Mississippi was again the lowest, with 8 percent, at 12 months. In Massachusetts, 23 percent of babies are still breast-fed at 12 months, just above the national level of 22 percent.

Breast milk is considered superior to formula because it is easier for babies to digest and contains antibodies from their mothers that can protect them from infections. Research has also shown that breast-fed babies are less likely than formula-fed babies to become overweight or obese during childhood and adolescence.

Hospital care can encourage breast-feeding and workplace policies can support women as they return to their jobs and continue to breast-feed, Dr. William Dietz, director of the CDC’s Division of Nutrition, Physical Activity, and Obesity, said in a statement issued with the report.

“We need to direct even more effort toward making sure mothers have the support they need in hospitals, workplaces, and communities to continue breast-feeding beyond the first few days of life, so they can make it to those 6- and 12-month marks,’’ he said.

The CDC also released figures for exclusive breast-feeding, meaning babies had nothing else to eat or drink. For Massachusetts babies, those rates are 38 percent at 3 months old and 21 percent at 6 months old. The national rates are 33 percent and 13 percent. ELIZABETH COONEY

Public data on doctors not linked to quality, study says

Rachel Reid and colleagues at the University of Pittsburgh and the RAND Corp. in Boston explored whether information posted on the website of the Massachusetts Board of Registration in Medicine correlated with more detailed data on quality of care that patients aren’t able to access. Using insurance company claims data, the researchers calculated performance scores for more than 10,000 Massachusetts physicians on 124 quality measures, such as their compliance with guidelines on cholesterol screenings and Pap tests.

The researchers then looked to see whether any public information correlated with the quality scores. Three factors were associated with higher quality: being female, graduating from a US medical school rather than a foreign one, and earning board certification.

The connections they found aren’t strong enough to suggest switching to a female, board-certified, US-educated doctor, though. The gap between scores for doctors with and without these characteristics is small and the variation among such doctors is wide, the researchers said.

“Overall, the results highlight the need for externally available quality information for consumers to use,’’ they write. E.C.

Friends help predict flu

Dr. Nicholas Christakis of Harvard and his research collaborator James Fowler of the University of California, San Diego, have analyzed social networks and how smoking or obesity can be “contagious,’’ flowing through a web of social contacts. Now they have turned their attention to how the novel strain of influenza called H1N1 circulated among Harvard students. Their study appears in PLoS ONE.

Last fall they asked more than 300 randomly selected undergrads to name three friends and to keep in touch with the researchers about whether they caught the flu. The researchers then asked more than 400 of the friends named to participate, while tracking participants’ visits to University Health Services.

The researchers were watching for the “friendship paradox,’’ which states that your friends have more friends than you do. Christakis and Fowler were looking to see if the popular people caught flu sooner than the control group.

Based on regular e-mail responses and records from health services, members of the friend group came down with flu symptoms two weeks before the randomly selected students.

In an interview, Christakis emphasized that they were not tracking the actual path of infections among the students. Instead, he and Fowler think that people with more friends are more likely to be out among other people, increasing their chances of catching the flu from friends or strangers.

Christakis says the findings could have public health implications. He envisions asking people in cities to name their friends, to provide early signals about the spread of a disease. E.C.