An MIT study published in Nature Communications found that juvenile mice exposed to NDMA, a carcinogen found in contaminated drinking water and some medications, suffered dramatically higher rates of DNA damage and cancer compared to adults. The key mechanism is cell proliferation rate: rapidly dividing juvenile liver cells convert DNA adducts into double-stranded breaks and mutations before repair can occur, while adult liver cells divide slowly and show far fewer mutations. The findings challenge standard toxicological testing protocols that use adult mice, potentially missing age-dependent vulnerabilities. The research may help explain elevated childhood cancer rates near a contaminated site in Wilmington, Massachusetts. Researchers also found that factors increasing cell proliferation in adults — such as high-fat diet, viral infection, or thyroid hormone — can raise adult susceptibility to NDMA as well.
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