A possible biological cause for SIDS Nutrition studies too often follow the money
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A dearth of receptors
Infants who died from SIDS had significantly fewer 5-HT1A receptors than controls, as shown in this brainstem tissue section. The red color indicates the greatest density of receptors.
New autopsy data provide the strongest evidence yet that sudden infant death syndrome (SIDS) has a concrete biological basis. Neuropathologist Hannah Kinney, MD, neuroscientist David Paterson, PhD, and colleagues found that babies who die from SIDS have abnormalities in the brainstem, the part of the brain that regulates breathing and arousal. They also found that male SIDS infants had significantly fewer serotonin receptors than female SIDS infants, perhaps explaining why SIDS strikes boys twice as often as girls.
The study, which was published in the Journal of the American Medical Association, examined brainstem tissue from 31 infants who died from SIDS and 10 who died from other causes. The SIDS infants had an abnormally high number of nerve cells that make and release serotonin. However, these neurons were often noticeably underdeveloped. They were also deficient in a protein that "recycles" serotonin and a certain type of serotonin receptor.
When babies sleep face down, they may re-breathe exhaled carbon dioxide (CO2). Normally, rising CO2 levels activate nerve cells in the brainstem, which then stimulate the brain's respiratory and arousal centers. The baby then wakes up, turns its head and breathes faster to get more oxygen. SIDS babies, however, may fail to rouse. The researchers now hope to develop a diagnostic test to identify infants at risk.
David Ludwig, MD, PhD
A recent study led by David Ludwig, MD, PhD, director of Children's Optimal Weight for Life (OWL) program, documents apparent biases in some studies of the nutritional content of beverages. The analysis showed that beverage studies funded solely by the beverage industry were four to eight times more likely to have conclusions that favored sponsors than studies done with no industry funding. The findings were published online in the January 9 issue of the journal PLoS Medicine.
Ludwig's was the first systematic analysis of nutrition studies, examining 111 studies related to the health effects of milk, soda and juice. Ludwig believes that the bias he uncovered may eclipse the bias that exists in pharmaceutical studies. "We don't all take drugs, but we eat every day," he says. "If the science is compromised by conflict of interest, that's a top-order threat to public health."
In his first book, Ending the Food Fight, coming out this spring, Ludwig gives dietary advice that he hopes will help stem the tide of childhood obesity. The book outlines Ludwig's groundbreaking low-glycemic diet strategy, and offers healthful recipes and tips on how parents can help their children make better eating decisions.
When it comes to preventing skin cancer, Children's researchers have found that the protein p53 appears doubly protective—it not only guards against cancer-causing DNA damage from the sun, it also kick-starts the tanning process, spurring production of skin-darkening melanin. "The number one risk factor for melanoma is fair skin that doesn't tan," notes study author David Fisher, MD, PhD. Fisher and colleagues are now trying to determine how this finding could be used to prevent skin cancer, even in people who don't tan well.
And for those who do tan poorly, it may be possible to create a protective tan medicinally. Fisher and colleagues did so in fair-skinned mice, using a topical cream. The active ingredient, forskolin, spurs melanin production by increasing levels of a chemical called cAMP in skin cells. Redheads and other fair-skinned people, who can't produce enough cAMP on their own, might someday benefit from forskolin or one of the other tanning compounds being studied in Fisher's lab.
Handheld computers are providing new insights into adolescents' sexual behavior. Children's researcher Lydia Shrier, MD, MPH, and colleagues closely tracked 67 sexually active youth, aged 15 to 21, paging them at random four to six times a day with a series of questions about their sexual activity and emotional state. The upshot? Most adolescents feel better after sex—a finding that may not be surprising, but will help health professionals craft more effective safer-sex messages.
The sharp dip in air travel after September 11, 2001, had an unexpected public health benefit: It slowed the spread of flu, says Children's researcher John Brownstein, PhD. Before the 9/11 attacks, flu deaths in the United States consistently peaked on or around February 17; after the attacks, the peak came March 2. It also took 53 days for flu to cross the country—versus an average of 33 days before the attacks. This information could be used to help slow a pandemic flu outbreak.
Why are Black women much more likely than White women to die from breast cancer, despite getting the disease less often? According to Children's researcher Michael Retsky, PhD, and colleagues, there may be two reasons: reduced access to health care and a tendency for Black women to develop breast cancer before menopause. Evidence suggests that surgically removing a tumor can encourage growth of metastases, especially when surgery occurs before menopause. The researchers urge direct study to probe these differences.
Could the hours of video games your teen plays make him aggressive? Could your preschooler's anxiety stem from the TV she watches? Visit www.cmch.tv/mentors/violence.asp, from Children's Center on Media and Child Health, to find out. This free, searchable, parent-friendly database provides findings from more than 700 studies investigating how violence in movies, television, music, video games, print media and the Internet affects children. Future databases will compile research associating media with obesity, sexual behavior, substance use and health problems.
For more of these studies and other news from Children's Hospital Boston, visit www.childrenshospital.org/newsroom.