Modelling trajectories of psychosomatic health complaints in children and adolescents: results of the BELLA study.

Psychosomatic health complaints (PHC) can significantly impair psychosocial development of children and adolescents and are therefore of considerable interest in health sciences and public health surveillance. Questions addressed the type of function that describes individual trajectories best, potential differences between these, and corresponding predictors from the perspective of both children and their parents. Based on the German population-based and representative BELLA cohort sample, 2,857 children and adolescents between 7 and 17 years of age at baseline were analysed over a period of 3 years with yearly follow-ups using mixed growth curve analyses. PHC were measured in accordance with the health behaviour in school-aged children-symptom checklist. The mean level of PHC was rather low, slightly lower for the parent report than for the self-report and significantly different between subjects. Concerning the parent report, the 2-year course is best described by a slowly increasing linear trend that decelerates somewhat over time. The increasing linear trend was more pronounced in the self-report from 11 to 17 years of age, but was significantly different for each subject and correlated with baseline scores. Trajectories could be explained by known predictors, most importantly by mental health problems of the child or adolescent. The results confirm the findings of previous studies and provide representative data about the individual short-term development of PHC in children and adolescents in Germany.