Adults exposed to secondhand cigarette smoke have about 1.5 times higher blood cadmium levels than those in smoke-free environments, according to a cross-sectional study published in Biological Trace Element Research. Active smokers had over three times higher levels.
The Study
Led by researchers at Texas A&M University, the study analyzed data from 1,380 children and teenagers and 3,686 adults drawn from national health surveys conducted between 2015 and 2020. Researchers measured levels of cadmium and the nicotine metabolite cotinine in blood and urine to categorize exposure.
Key Findings
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Adults: Blood cadmium levels increased with the severity of smoke exposure. Heavy secondhand exposure was linked to 1.5 times higher cadmium levels, while active smoking was associated with over three times higher levels.
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Children and teenagers: No significant change in cadmium levels was observed with smoke exposure.
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Biological sex: Across all age groups, women had higher cadmium levels than men, a difference attributed to higher gastrointestinal absorption of the metal.
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Disparities: Racial minority groups, individuals with lower income, and those with less education were associated with higher cadmium exposure, likely due to housing, environmental, and socioeconomic factors.
Cadmium accumulates in the body over decades and is linked to kidney, lung, and prostate cancers, as well as kidney failure and bone disease.
Implications
The study underscores that secondhand smoke is a significant source of cadmium exposure, a toxic metal that accumulates in the body over decades and is linked to serious health conditions, including kidney, lung, and prostate cancers, as well as kidney failure and bone disease.
Study Limitations
The researchers note that cotinine, a nicotine marker, remains in the body for only 15–20 hours, making it difficult to reliably distinguish between occasional smokers and individuals with heavy secondhand exposure. Longer-term studies are needed to confirm and extend these findings.