Year of Publication



Public Health

Date Available


Degree Name

Master of Public Health (M.P.H.)

Committee Chair

Mary (Beth) Lacy Leigh, PhD

Committee Member

Erin Abner, PhD, MPH

Committee Member

Anna Kucharska-Newton PhD, MPH



Objective: To determine if diabetes locus of control (dLOC) is associated with depression in older adults with type 1 and type 2 diabetes and whether this association differs by diabetes type.

Methods: Data for the current study were obtained from The Study of Longevity in Diabetes (SOLID), a prospective cohort study of aging, and diabetes. SOLID participants aged 60 and older with type 1 diabetes (T1D), type 2 diabetes (T2D), and without diabetes were recruited from members of Kaiser Permanente Northern California (KPNC). For the current study, we excluded all of the participants without diabetes since the primary exposure, diabetes locus of control (dLOC), was not applicable in this population. This resulted in a final analytic sample of 1053 (n=805 with T1D and n=248 with T2D). Cross-sectional associations between dLOC and depression (ascertained using the 15-item Geriatric Depression Scale [GDS]) were estimated using covariate-adjusted linear and logistic regression models.

Results: Overall, the mean dLOC score was higher in individuals with T1D (mean=7.4, SD=3.2) than in those with T2D (mean=5.8, SD=3.4; p value<0.0001), indicating those participants with T1D had a more internal locus of control than those with T2D. Overall, 13.9% of participants had GDS scores indicating depression. The prevalence of depression did not differ by diabetes type (13.7% in T1D, 14.6% in T2D; p value=0.71). In fully adjusted regression analyses, a one-unit increase in dLOC (i.e. more internal dLOC) was associated with a lower depression score (β=-0.11; 95% CI: -0.15, -0.06) and lower odds of having depression (OR=0.91; 95% CI: 0.85, 0.96).

Conclusion: In adults over 60 with either type 1 or type 2 diabetes, we found that higher dLOC scores were associated with lower depressive symptoms. Individuals with T1D had higher dLOC scores than individuals with T2D, indicating stronger internal dLOC in those with T1D. The association between mean depression score and dLOC did not differ by diabetes type.

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