‘Safe’ Blood Lead Levels Can Cause Cognitive Deficits
I’ve mentioned before that heavy metals are a seldom-sought after component of many of today’s chronic diseases. This article suggests that, even at dosages generally considered “safe,” that IQ suffers in suseptable children. Think of todays’ “disordered” children with ADD and ADHD–could lead be a contributing factor? Vit C is known to reduce the absorption of lead from the GI tract–could todays’ kids be absorbing more lead because the intake of Vit C from fresh fruits and veggies is at an all time low? Personally, the concept of having a “safe” level of most heavy metals is beyond me. “Safe”, when it comes to the US Government, means that no obvious disease state occurs at that level of exposure.
Pediatric Academic Societies Annual Meeting in Baltimore Lead can cause cognitive deficits in children even when blood levels are well below the officially sanctioned 10 µg/dL mark, according to study results presented Monday at the Pediatric Academic Societies Annual Meeting in Baltimore. The concentration for defining lead intoxication has been lowered progressively from 60 µg/dL to 10 µg/dL over the past three decades, explained Dr. Bruce Lanphear from Children’s Hospital Medical Center in Cincinnati, Ohio. But he described the choice of 10 µg as arbitrary, saying that it remains unclear whether lower levels are actually harmless. Dr. Lanphear and his associates measured blood lead levels during the first 5 years of life and IQ at 60 months in 276 children and adjusted their comparisons for factors with a recognized influence on child IQ (sex, birthweight, maternal IQ, in utero tobacco exposure, and so on). Dr. Lanphear reported that the mean blood lead level at 60 months was 6.1 µg/dL and the mean IQ was 90. The mean blood lead level rose from 1.9 µg/dL at 6 months of age to peak at 9.3 µg/dL at 24 months, when 33.8% of children had levels above the 10 µg/dL “safe” cutoff, Dr. Lanphear said. “There was a consistent inverse association between blood lead level and IQ,” Dr. Lanphear noted, “which proved statistically significant beginning at 36 months of age.” Overall, Dr. Lanphear said, there was a 5.7-point drop in IQ for each 10-µg/dL increase in blood lead level. But among children with lower lead levels, the effect of rising lead levels was more striking: an 11.5-point drop for those whose levels were initially below 10 µg/dL and more than a 15-point drop for children whose lead levels were initially below 5 µg/dL.