A review of the evidence to support interim reference level for dietary lead exposure in adults.

FDA developed the interim reference level (IRL) for lead of 3 µg/day in children and 12.5 µg/day in women of childbearing age (WOCBA) to better protect the fetus from lead toxicity. These IRLs correspond to a blood lead level (BLL) of 0.5 µg/dL in both populations. The current investigation was performed to determine if the IRL for WOCBA should apply to the general population of adults. A literature review of epidemiological studies was conducted to determine whether a BLL of 0.5 µg/dL is associated with adverse effects in adults. Some studies reported adverse effects over a wide range of BLLs that included 0.5 µg/dL adding uncertainty to conclusions about effects at 0.5 µg/dL; however, no studies clearly identified this BLL as an adverse effect level. Results also showed that the previously developed PTTDI for adults of 75 µg/day lead may not be health protective, supporting use of a lower reference value for lead toxicity in this population group. Use of the 12.5 µg/day IRL as a benchmark for dietary lead intake is one way FDA will ensure that dietary lead intake in adults is reduced.

Lead exposures in older children (males and females 7-17 years), women of childbearing age (females 16-49 years) and adults (males and females 18+ years): FDA total diet study 2014-16.

Dietary exposures to lead were estimated for older children, females of childbearing age and adults based on lead concentration data from the FDA's Total Diet Study and on food consumption data from What We Eat In America (WWEIA), the food survey portion of the National Health and Nutrition Examination Survey (NHANES). Estimated mean exposures varied based on the population and on the three different substitution scenarios for lead values below the limit of detection (non-detects = 0; non-detects = limit of detection; hybrid approach). Estimated mean lead exposures range from 1.4 to 4.0 µg/day for older children (males and females 7-17 years), 1.6 to 4.6 µg/day for women of childbearing age (females 16-49 years) and 1.7 to 5.3 µg/day for adults (males and females 18 years and older). Estimated 90th percentile lead exposures range from 2.3 to 5.8 µg/day for older children, 2.8 to 6.7 µg/day for women of childbearing age and 3.2 to 7.8 µg/day for adults. Exposure estimates suggest some older children may be exposed to dietary lead above the FDA interim reference level for lead in children of 3 µg/day. The results of this study can be used by the FDA to prioritise research and regulatory efforts in the area of dietary lead exposure.

U.S. Food and Drug Administration's interim reference levels for dietary lead exposure in children and women of childbearing age.

Reducing lead exposure is a public health priority for the US Food and Drug Administration as well as other federal agencies. The goals of this research were to 1) update the maximum daily dietary intake of lead from food, termed an interim reference level (IRL), for children and for women of childbearing age (WOCBA) and 2) to confirm through a literature review that with the exception of neurodevelopment, which was not evaluated here, no adverse effects of lead consistently occur at the blood lead level (BLL) associated with the IRL. Because no safe level of lead exposure has yet been identified for children's health, the IRLs of 3 µg/day for children and 12.5 µg/day for WOCBA were derived from the Centers for Disease Control and Prevention reference value of 5 µg/dL BLL, the level at which public health actions should be initiated. The literature review showed that no adverse effects of lead consistently occurred at the BLL associated with the IRLs (0.5 µg/dL). The IRLs of 3 µg/day for children and 12.5 µg/day for WOCBA should serve as useful benchmarks in evaluating the potential for adverse effects of dietary lead.