To follow up on a thread from yesterday, FDA's decision to let silicon gel filled breast implants back on the market is noteworthy for two other reasons not mentioned by my colleagues. The first real breakthrough on this front was back in 1999, when a federal judge in Alabama appointed a National Science Panel pursuant to a Daubert motion to investigate the reliability of the plaintiffs' expert witnesses in the Silicone Gel Breast Implant Products Litigation. The panel examined the epidemiological evidence available as of 1999 and concluded that breast implants were associated with an increase the relative risk of rheumatoid arthritis and other autoimmune and rheumatic conditions by 15 percent (not statistically significant); dermatomyositis and polymyositis by 52 percent (not statistically significant); definite connective tissue diseases by 14 percent (statistically significant at the 95 percent confidence level); and SjÃ¶gren's Syndrome by 47 percent (statistically significant). But Judge Sam Pointer threw out the case anyway. Why? Because the panel of epidemiologists informed Pointer that an increase in relative risk of less than 100 percent (or an odds ratio lower than 2.00) is very weak. When risk factors are lower than that, it is difficult to separate any signal in the data from the statistical noise, and policymakers are cautioned to take such associations with a large dose of salt. Score one for the good guys. The second reason this is significant has nothing to do with fake boobs, but with cigarettes. We all know, of course -- since the public health nannies have been telling us for years -- that secondhand smoke is a known human carcinogen. So, how bad is secondhand smoke? Most of the major studies estimate that the increased the likelihood that non-smokers would develop lung cancer from daily exposure to secondhand smoke is roughly 20 to 30 percent (or an odds ratio of 1.2 to 1.3). Give yourself a gold star if you noticed that this risk is in the same range as that created by silicon breast implants. Thus, by acknowledging that the risk of silicon gel filled breast implants is essentially meaningless, the FDA has (unwittingly, I assume) cast doubt on the government's repeated scary pronouncements on secondhand smoke.