Confidence interval function analysis to evaluate the risk of mesothelioma among an expanded international cohort of cosmetic talc miners and millers.

We used pooled data from international cosmetic talc miner/miller cohorts to determine whether hypothesized increased mesothelioma risks are consistent with the observed data. We evaluated the confidence interval function for the observed pooled mesothelioma SMRs (observed = 1; expected = 3.17, 3.34, or 3.60), and calculated the value of α for the upper 100(1 - 2α)% confidence limit that equals various SMRs of interest (1.5, 2.0, 2.5, 3.0). Using the mid-value estimate of expected number of cases (3.34), the probability (α) that the true mesothelioma SMR is at or above 2.0, or at or above 3.0 is 0.0096 and 0.0005, respectively. Thus, a mesothelioma SMR ≥2.0 is not compatible with the observed pooled data, providing further support for our conclusion that cosmetic talc exposure is not associated with an elevated risk of mesothelioma.