Empirical evidence of long-term health effects of social isolation in young people is
limited. In childhood, the school class emerges as a central context, wherein social
disadvantages may be detrimental for health development. The purpose of this study was to examine social isolation in the school class and its association with adult disease. Data was derived from a longitudinal study using a 1953 cohort born in Stockholm, Sweden (n = 14,294). Two types of social isolation in the classroom, friendlessness and marginalisation, were sociometrically assessed in 6th grade (1966). Information on adult health was gathered through registry-data on in-patient care (1973–2003). Analyses were based on logistic regression and Poisson regression. The results demonstrated that both types of social isolation in the school class were related to various adverse individual, schoolrelated and family-related aspects. Moreover, while marginalisation was associated with the odds of becoming hospitalised, friendlessness was not. However, if ever being
hospitalised, both types of isolates had significantly more hospital care events. These results were largely unexplained by the included individual, school-related and familyrelated aspects.