How much does the combination of smoking and exposure to asbestos increase the likelihood of lung cancer?

The combination of smoking and exposure to asbestos significantly elevates the risk of developing lung cancer due to the synergistic effects of both carcinogenic factors. While asbestos exposure alone is known to increase lung cancer risk, smoking further compounds this risk, leading to a much higher likelihood of disease. Research shows that individuals who both smoke and have had asbestos exposure face a lung cancer risk that can be 90 times greater than that of individuals who do not smoke and have no asbestos exposure.

This phenomenon is attributed to the additive and multiplicative effects of the two risk factors, where the presence of one exacerbates the harmful effects of the other. Thus, the figure of 90 times is supported by various epidemiological studies that have documented this increased risk, providing a clear context for the significant danger posed by combining these two risk factors.

The other figures, while they suggest an increased risk, do not align with the majority of research findings that have established this particular combination's associated risk as being around 90 times more likely to contribute to lung cancer compared to non-smokers without exposure to asbestos.