Illness identity and adjusting to type I diabetes: A four-wave longitudinal study.

Objectives.Prior research has linked illness identityor the extent to which the illness is integrated into one's identityto diabetes-specific functioning.Four illness identity dimensions have been identified: rejection, acceptance, engulfment, and enrichment.As longitudinal research on this topic is scarce, this study examined developmental trajectories of illness identity and prospective associations between illness identity and diabetes-specific functioning.Methods.Adolescents and emerging adults with type 1 diabetes, aged 14 to 25 (Mage=19; 54% girls), participated in a four-wave longitudinal study spanning 3 years (N=559 at Time 1).Participants filled out questionnaires on illness identity, treatment adherence, and diabetesspecific distress.HbA1c-values were obtained from participants' medical records.To chart the development of illness identity over time, we performed latent growth curve modeling.Crosslagged analysis was used to examine prospective associations between illness identity and diabetes-specific functioning. Results.We observed small linear increases in acceptance (Mslope=.05,p<.01) and engulfment (Mslope=.03,p<.05) and a small linear decrease in rejection (Mslope=-.08,p<.001) across waves (with scale scores ranging between 1 and 5).Rejection negatively predicted and enrichment positively predicted treatment adherence one year later which, in turn, positively predicted enrichment and negatively predicted engulfment over time.Furthermore, rejection and engulfment positively predicted diabetes-specific distress one year later.Finally, diabetesspecific distress and HbA1c positively predicted engulfment one year later.Standardized crosslagged coefficients ranged between |.05| and |.11|. Conclusions.We identified small but interesting changes in three out of four illness identity dimensions.Prospective associations between illness identity and diabetes-specific functioning were bidirectional in nature.