Neophytou AM, et al. - Researchers used logistic regression to evaluate dose–response links between plasma cotinine-determined secondhand smoke (SHS) exposure and asthma outcomes in minority children ie, Latino and African-American children with asthma from the mainland USA and Puerto Rico. They used a continuous exposure variable in generalised additive logistic models with penalised splines in order to assess the shape of dose–response links. They found higher odds of asthma exacerbations and having poorly controlled asthma related to SHS exposure. They noted even at low levels of exposure, an increasing dose–response link was present. The conclusion that there are no safe levels of SHS exposures was supported by these data.