Risk factors for stuttering: a secondary analysis of a large data base.

The spectrum of risk and concomitant factors in stuttering is generally thought to be wide and heterogeneous. However, only a few studies have examined these factors using information from large databases. We examined the data on 11,905 Swiss conscripts from 2003. All cases with high psychiatric screening scores indicating "caseness" for a psychiatric disorder were excluded, among them potential malingerers, so that 9,814 records remained. The analyses rely on self-reported information about stuttering in childhood, problems at birth, problems in school, mental disorders of parents and relatives, childhood adversity and socio-demographic information. Statistical modelling was done using logistic regression and path analysis models. Risk factors determined in the logistic regression include premature birth, probable attention deficit hyperactive disorder, alcohol abuse of the parents, obsessive-compulsive disorder in parents and relatives, having a disabled mother and having a parent from a foreign country. There is no overwhelmingly strong risk factor; all odds ratios are about 2 or below. In conclusion, large databases are helpful in revealing less obvious and less frequent risk factors for heterogeneous disorders such as stuttering. Obviously, not only secondary analyses, but also systematical large scale studies would be required to complete the complex epidemiological puzzle in stuttering. An extensive examination of young adults who were initially assessed in childhood might provide the most promising design.