NEW YORK NURSE: July/August 2008
By Patricia Many, MS, RN, SUNY Institute of Technology, for the Foundation Center for Nursing Research Planning Committee
Recently there have been multiple product and toy recalls due to a potential lead hazard. While this is a real concern for many Americans, what does this means for nurses who care for children? It is well known that high levels of lead in the blood can adversely affect cognitive development in children. However, the lowest lead level that poses a threat to children is still being debated.
Historically, a blood lead level (BLL) >10 µg/dL was established as the lowest level of concern for children’s development (Gilbert & Weiss, 2006). This number continues to shift, however, as more research is done. The minimum blood lead level that poses a health concern for children was recently addressed through research conducted by Surkan and colleagues (2007).
The study assessed the impact that a BLL ≤10µg/dL had on mental and behavioral development of 534 English-speaking children ages 6-10 from the New England area. The following characteristics were included: no history of mercury dental fillings, initial baseline BLL not greater than 10 µg/dL, no diagnosis of mental or behavioral conditions, and no diagnosis of renal disease.
Outcomes were measured using the Wechsler Intelligence Scale for Children to determine the children’s intelligence quotient (IQ). This battery of tests examines cognition (thinking) and specifically looks at vocabulary, comprehension, picture arrangement, block design, and maze completion. A second measurement focused on performance using the Wechsler Individual Achievement Test which examines reading, math, and spelling. An additional series of tests were performed to assess fine motor skills, memory, attention, verbal tests, finger tapping, and reaction time.
Statistical analyses were performed to determine the relationship between BLL and cognition and motor skills. Children with a BLL of 1-2 µg/dL were compared to children with a BLL of 3-4 µg/dL and 5-10 µg/dL. The results indicate that children with a BLL of 5-10 µg/dl scored lower, especially in vocabulary, math, reading, attention span, and working memory.
Overall, this research suggests that, compared to children with a BLL of 1-2 µg/dL and 3-4 µg/dL, children with a BLL of 5-10 µg/dL do have a decrease in cognition, even when controlling for sociodemographic characteristics such as race, income, and IQ. This level is lower than the current standard of 10 µg/dL. It should be noted that a limitation of this study was that this was a one-time assessment of lead level and it is unknown if these children had a history of elevated BLL in previous years or over time.
This study suggests that a BLL <10 µg/dL does pose a risk to children’s health. Determining the minimum BLL is significant not only because of the potential health concern for children, but also to gain support for resource allocation. Awareness of the minimum blood lead action level is important to facilitate evidence-based nursing policies and interventions aimed at prevention for children.
What does this mean for you? Lead levels lower than the current standard for alarm can adversely affect children’s health and intelligence. Nurses working with children have an opportunity to identify children potentially at risk or to capture those already exposed to lead. RNs should continue to follow research on this evolving national health issue in order to best advocate for and educate our patients and their families.
Gilbert, S. G., & Weiss, B. (2006). A rationale for lowering blood lead action level from 10 to 2 µg/dl. Neurotoxicology, 27, 693-701.
Surkan, P. J., Zhang, A., Trachtenberg, F., Daniel, D. B., McKinlay, S., & Bellinger, D. C. (2007). Neuropsychological function in children with blood lead levels <10 µg/dl. Neurotoxicology, 28, 1170-1177.