Educational level as a moderator of the relationship between body mass index, blood pressure, and depressive symptoms in the Peruvian population: a moderated mediation analysis.

OBJECTIVE

To analyse whether systolic blood pressure influences the relationship between body mass index and depressive symptoms, and whether educational level moderates these associations in Peruvian adults.

METHODS

Cross-sectional study using data from the Peruvian Demographic and Health Survey (ENDES). Individuals aged ≥15 years were included. Depression was assessed with the PHQ-9 (continuous score); BMI and SBP were treated as continuous variables. A moderated mediation model (PROCESS model 59) was applied, adjusting for alcohol consumption, age, mother tongue, ethnic identity, and marital status.

RESULTS

In the moderated analysis, BMI showed a positive association with SBP (B = 0.61; 95% CI: 0.57-0.66), with a stronger effect in individuals with higher education (B = 0.81) compared to those with basic education (B = 0.61). Alcohol consumption (B = 1.20), speaking an indigenous mother tongue (B = 1.26), and age (B = 0.42 per year) were associated with higher SBP, while living with a partner was protective (B = -2.05). In the model for depressive symptoms, BMI (B = 0.04) and SBP (B = 0.02) increased PHQ-9 scores; the effect of SBP was greater among higher-educated individuals (B = 0.036) than those with basic education (B = 0.022). The moderated mediation showed that the indirect component via SBP was higher in individuals with higher education (B = 0.081) than in those with basic education (B = 0.035), with a moderated mediation index of 0.040 (95% CI: 0.028-0.052).

CONCLUSIONS

Educational level modulates the relationship between BMI, blood pressure, and depression, highlighting health inequalities that can inform public health strategies and prevention policies.