2012年10月24日
Ferragamo Bag
Although the latest study is likely to strengthen concerns about BPA's effects on human hormones, its authors caution that they are far from finding a cause-and-effect link between BPA and obesity. Their findings, they wrote, are "at best hypothesis generating,Ferragamo Outlet."
The absence of an association between BPA exposure and obesity in African Americans was particularly perplexing because researchers found some of the highest levels of BPA in the urine of black participants,Ferragamo Bag,Ferragamo Bag. (By contrast,Ferragamo Handbag, some of the lowest BPA-exposure readings researchers found in the study were in young Latinos,Ferragamo Outlet, the researchers noted.)
Lead author Dr. Leonardo Trasande called the ethnic differences "striking" and acknowledged that he and his colleagues were mystified by them.
"We know of no behavior in obese white children" that would make them more prone to weight gain when exposed to BPA than children of other ethnicities, Trasande said in a news conference.
What was clear is that,Ferragamo Handbag, where BPA exposure and obesity were linked, it did not take much to make a difference.
The researchers used data collected in 2003 and 2004 as part of the National Health and Nutrition Examination Survey,Ferragamo Bag, which allows the Centers for Disease Control and Prevention to track national trends in health behaviors and obesity,Ferragamo Bag. They divided the participants into four groups on the basis of the BPA content in their urine a crude measure of ongoing exposure to the chemical.
White children whose BPA readings fell in the lowest 25% were clearly less likely to have a weight problem: Only 4.7% of the group weighed in as obese.
Above that low level of exposure, however, obesity rates rose rapidly and did not correspond closely with stronger doses of BPA: Among the group whose BPA exposure lay in the second-lowest quartile, 17,Ferragamo Bag.5% were obese, along with 17,Ferragamo Outlet.1% of those in the next-highest category of BPA exposure. Among the 25% of white childrenwith the highest level of BPA in their urine, 22.8% were obese,Ferragamo Bag.
When the dose of a potentially harmful agent does not track well with an observed effect such as obesity,Ferragamo Outlet, "it's tricky to know where to go with it," said David B. Allison, a University of Alabama at Birmingham epidemiologist who was not involved in the study,Ferragamo Handbag,Ferragamo Handbag. It's possible that BPA exposure could be causing the obesity, but unseen factors could be intervening to create the effect, he said.
The NYU researchers offered several potential explanations for the apparent link. Perhaps, they suggested, the acidity of a canned food affects the degree to which BPA is taken up by the body. Perhaps differing dietary choices may account for differences in ethnic groups' response to BPA. Perhaps exposure to BPA in a child's earliest years have a more potent effect than exposure later in childhood.
It would be difficult to conduct the clinical trials that could establish a firmer causal link between BPA and obesity because neither researchers nor parents would want to expose children to unnecessarily high levels of BPA, said Allison, who directs the Nutrition Obesity Research Center at his university.
Trasande said such trials would be done "in the ideal world." In the meantime, he added,Ferragamo Outlet, "it would be too early to make particular recommendations" to consumers about reducing BPA exposure in a bid to prevent obesity.
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The absence of an association between BPA exposure and obesity in African Americans was particularly perplexing because researchers found some of the highest levels of BPA in the urine of black participants,Ferragamo Bag,Ferragamo Bag. (By contrast,Ferragamo Handbag, some of the lowest BPA-exposure readings researchers found in the study were in young Latinos,Ferragamo Outlet, the researchers noted.)
Lead author Dr. Leonardo Trasande called the ethnic differences "striking" and acknowledged that he and his colleagues were mystified by them.
"We know of no behavior in obese white children" that would make them more prone to weight gain when exposed to BPA than children of other ethnicities, Trasande said in a news conference.
What was clear is that,Ferragamo Handbag, where BPA exposure and obesity were linked, it did not take much to make a difference.
The researchers used data collected in 2003 and 2004 as part of the National Health and Nutrition Examination Survey,Ferragamo Bag, which allows the Centers for Disease Control and Prevention to track national trends in health behaviors and obesity,Ferragamo Bag. They divided the participants into four groups on the basis of the BPA content in their urine a crude measure of ongoing exposure to the chemical.
White children whose BPA readings fell in the lowest 25% were clearly less likely to have a weight problem: Only 4.7% of the group weighed in as obese.
Above that low level of exposure, however, obesity rates rose rapidly and did not correspond closely with stronger doses of BPA: Among the group whose BPA exposure lay in the second-lowest quartile, 17,Ferragamo Bag.5% were obese, along with 17,Ferragamo Outlet.1% of those in the next-highest category of BPA exposure. Among the 25% of white childrenwith the highest level of BPA in their urine, 22.8% were obese,Ferragamo Bag.
When the dose of a potentially harmful agent does not track well with an observed effect such as obesity,Ferragamo Outlet, "it's tricky to know where to go with it," said David B. Allison, a University of Alabama at Birmingham epidemiologist who was not involved in the study,Ferragamo Handbag,Ferragamo Handbag. It's possible that BPA exposure could be causing the obesity, but unseen factors could be intervening to create the effect, he said.
The NYU researchers offered several potential explanations for the apparent link. Perhaps, they suggested, the acidity of a canned food affects the degree to which BPA is taken up by the body. Perhaps differing dietary choices may account for differences in ethnic groups' response to BPA. Perhaps exposure to BPA in a child's earliest years have a more potent effect than exposure later in childhood.
It would be difficult to conduct the clinical trials that could establish a firmer causal link between BPA and obesity because neither researchers nor parents would want to expose children to unnecessarily high levels of BPA, said Allison, who directs the Nutrition Obesity Research Center at his university.
Trasande said such trials would be done "in the ideal world." In the meantime, he added,Ferragamo Outlet, "it would be too early to make particular recommendations" to consumers about reducing BPA exposure in a bid to prevent obesity.
相的主文章：