Among 29,652 US adults aged 40 and older in NHANES 1999–2018, followed through 2019 with 7,215 deaths, each doubling of urinary cadmium was associated with 1.5 fewer years of follow-up survival, and each doubling of whole-blood lead with about 0.6 to 0.7 fewer years. Losses were largest at the 10th survival quantile, where early deaths cluster. Cadmium held up after adjusting for lead. Arsenic metabolites showed no clear association, and mercury unexpectedly looked protective.
The quantile approach is the novelty: instead of one hazard ratio, it shows how exposure shifts the timing of early deaths, a more intuitive metric than relative risk. The cadmium and lead signals fit decades of evidence linking both metals to cardiovascular and kidney disease. Smoking is the dominant cadmium source for most adults, so the practical message is familiar: avoid tobacco and secondhand smoke, and diets heavy in organ meats, shellfish and some leafy greens or grains from contaminated soil add cadmium. Importantly, this is observational, with single baseline measurements and no proof of causation. Residual confounding by smoking intensity, income and diet is likely; the authors themselves attribute the mercury result to such confounding, which should temper confidence in all metal estimates. Associations were also modest in absolute size and apply to population averages, not individual prognosis. This is a preprint that has not been peer reviewed, so figures may change. Editorially, the work is incremental: it confirms known toxicity with a new analytic lens rather than overturning anything.