TSNA exposure from cigarette smoking: 18Years of urinary NNAL excretion data.

Highlights: [•] We gathered published data of urinary NNAL excretion among cigarette smokers. [•] The data suggest TSNA exposure has declined among cigarette smokers over the past 18years. [•] The decline in TSNA exposure is not explained by a decline in cigarettes smoked per day. [•] These findings are consistent with reductions in cigarette tobacco and smoke TSNA levels. [Copyright &y& Elsevier]