Fig. 4
Standardized path model illustrating the relationships among DM, PSQI scores, and overall VFQ scores. This standardized path model illustrates the relationships among DM, PSQI scores, and overall VFQ scores, while controlling for gender, age, and educational level. Path coefficients are displayed alongside the arrows. The diagram shows that DM has a direct negative effect on overall VFQ scores (β = -0.170) and an indirect negative effect mediated by PSQI scores (β=-0.453 * 0.274 = -0.124). Error terms (e1, e2, e3) are included to account for the unexplained variance in PSQI and VFQ scores. *P < 0.05, ** P < 0.01, *** P < 0.001.
