"Safe" blood lead levels linked to risk of death
American Heart Association rapid access journal report
DALLAS, Sept. 19 – Blood lead levels generally considered safe may be associated with an increased risk of death from many causes, including cardiovascular disease and stroke, according to a report in Circulation: Journal of the American Heart Association.
Researchers studied lead levels below 10 micrograms per deciliter (µg/dL), which previously has been considered safe.
The levels studied are common and considerably lower than lead levels perceived by the government as a concern to public health, said Paul Muntner, Ph.D., author of the study and an associate professor of epidemiology and medicine at Tulane University School of Public Health and Tropical Medicine in New Orleans.
“Our study found the association of blood lead with cardiovascular death to be evident at levels as low as 2 μg/dL,” he said. “Since 38 percent of U.S. adults had lead levels above 2 μg/dL in 1999–2002, the public health implications of these findings are substantial.”
“我们的研究发现心血管死亡与血铅的相关性在低至2 μg/dL的水平很明显，”他说。“因为1999-2002年期间美国有38%的成年人血铅水平高于2 μg/dL，所以这些发现对于公共卫生的意义是非常重大的。”
The Occupational Safety and Health Administration (OSHA) defines high blood lead in adults as higher than 40 µg/dL. The Centers for Disease Control and Prevention recommend that women of child-bearing age have blood lead levels below 10 µg/dL.
职业安全卫生管理局（OSHA）将成年人血铅水平高于40 µg/dL定义为高血铅。疾病控制与预防中心推荐的育龄妇女血铅水平是低于10 µg/dL。
Researchers said the study questions the current belief about what lead levels are safe in the population.
“We wanted to know whether there was an association between the current blood lead levels among adults and coronary heart disease, stroke or cancer,” Muntner said.
Since the mid-1970s, when lead was no longer added to gasoline or household paint and lead was banned for use in soldering food cans, average blood lead levels in American adults have decreased from 13.1 µg/dL to 1.6 µg/dL.
自从上个世纪70年代中期以来（那时铅不再被添加到汽油或家用油漆，而且被禁用于锡焊食品罐头），美国成年人的平均血铅水平已从13.1 µg/dL降至1.6 µg/dL。
“Even though lead levels are much lower than before, the current levels are still orders of magnitude higher than pre-industrial levels,” Muntner said.
Today lead is mostly used to make batteries. It is also used to make ammunition (bullets), pipes and roofing materials. According to OSHA, exposure to lead can occur in at least 120 occupations including lead smelting, battery manufacturing, ship building/repair, auto manufacturing and printing.
Breathing contaminated air, eating contaminated food or soil, or drinking contaminated water are ways people can be exposed to lead. Inhalation of airborne lead is generally the most significant source of occupational lead absorption.
The researchers used data from the Third National Health and Nutrition Examination Survey Mortality Follow-Up Study, involving 13,946 adults whose blood lead levels were collected and measured between 1988 and 1994.
作者:admin@医学,生命科学 2011-08-24 17:17