摘要：We read with interest the article by Kalkbrenner et al. (2012) in which they explored maternal smoking during preg-nancy as a risk factor for autism spectrum dis orders (ASD). We believe that the follow-ing short comings of the study did not allow an evaluation of the results and therefore that the paper provides little evidence to judge whether data suggest a "link."The findings of Kalkbrenner et al. (2012) regarding "higher-functioning" ASD include three null associations and one association in the smallest subgroup of 375 cases (ASD-not otherwise specified; ASD-NOS) that was "statistically significant" only in sensitivity analysis. Therefore, we question their inter-pretation of the data when an effect was sug-gested in only one of the four tests of the same hypothesis. Furthermore, ASD-NOS is a difficult diagnostic subtype to understand because it includes, as the authors noted, a hetero geneous mixture of diagnoses
