Cadmium, environmental exposure, and health outcomes.

We provide an update of the issues surrounding health risk assessment of exposure to cadmium in food. Bioavailability of ingested cadmium has been confirmed in studies of persons with elevated dietary exposure, and the findings have been strengthened by the substantial amounts of cadmium accumulated in kidneys, eyes, and other tissues and organs of environmentally exposed individuals. We hypothesized that such accumulation results from the efficient absorption and systemic transport of cadmium, employing multiple transporters that are used for the body's acquisition of calcium, iron, zinc, and manganese. Adverse effects of cadmium on kidney and bone have been observed in environmentally exposed populations at frequencies higher than those predicted from models of exposure. Population data raise concerns about the validity of the current safe intake level that uses the kidney as the sole target in assessing the health risk from ingested cadmium. The data also question the validity of incorporating the default 5% absorption rate in the threshold-type risk assessment model, known as the provisional tolerable weekly intake (PTWI), to derive a safe intake level for cadmium.

Cadmium, environmental exposure, and health outcomes / O cádmio, a exposição ambiental ao cádmio e as consequências para a saúde

We provide an update of the issues surrounding health risk assessment of exposure to cadmium in food. Bioavailability of ingested cadmium has been confirmed in studies of persons with elevated dietary exposure, and the findings have been strengthened by the substantial amounts of cadmium accumulated in kidneys, eyes, and other tissues and organs of environmentally exposed individuals. We hypothesized that such accumulation results from the efficient absorption and systemic transport of cadmium, employing multiple transporters that are used for the body's acquisition of calcium, iron, zinc, and manganese. Adverse effects of cadmium on kidney and bone have been observed in environmentally exposed populations at frequencies higher than those predicted from models of exposure. Population data raise concerns about the validity of the current safe intake level that uses the kidney as the sole target in assessing the health risk from ingested cadmium. The data also question the validity of incorporating the default 5 percent absorption rate in the threshold-type risk assessment model, known as the provisional tolerable weekly intake (PTWI), to derive a safe intake level for cadmium.

Uma atualização sobre as questões relacionadas à avaliação dos riscos de saúde, oriundos da exposição a cádmio nos alimentos, é apresentada. Em um estudo de indivíduos sujeitos a uma elevada exposição dietária ao cádmio, a biodisponibilidade do cádmio ingerido foi confirmada, e os achados foram reforçados, diante da constatação de quantidades substanciais de cádmio acumulado, seja nos rins, nos olhos, assim como em outros tecidos e órgãos de pessoas ambientalmente expostas. Levantamos a hipótese de que essa acumulação seria o resultado de uma absorção eficiente do cádmio e do seu transporte sistêmico na absorção dos elementos cálcio, ferro, zinco e manganês pelo corpo humano. Os dados populacionais encontrados têm gerado uma preocupação quanto à validade do nível, atualmente aceito, de ingestão cádmica isenta de riscos, os rins constituindo o objeto único desses levantamentos de avaliação dos riscos à saúde, provenientes da ingestão de cádmio. Os dados também nos levam, na inferência do nível de ingestão cádmica isenta de riscos, a questionar a validade de se incorporar no modelo de avaliação de riscos para a determinação do limiar a taxa default de 5 por cento, conhecida como nível tolerável de ingestão proporcionada semanalmente (PTWI).