Publication:

The combined effects of blood lead exposure and chronic psychosocial stress on cardiovascular, inflammatory and cardiometabolic biomarkers among U. S. adults: a survey-weighted analysis of NHANES 2013-2014

Background Lead exposure remains a public health concern, with low-level exposure associated with adverse cardiovascular and inflammatory outcomes. Depressive symptoms may influence cardiovascular responses to environmental toxicants through overlapping biological pathways. This study examined whether depressive symptom burden modified associations between blood lead exposure and cardiovascular, inflammatory, and cardiometabolic biomarkers among U. S. adults.

Methods A cross-sectional analysis was conducted using NHANES 2013-2014 data. The analytic sample included 5,924 adults with available blood lead, patient health questionnaire-9 (PHQ-9), outcome, and covariate data. Survey-weighted multivariable linear regression models accounted for the NHANES complex sampling design and examined interactions between blood lead concentration and PHQ-9 score for mean systolic and diastolic blood pressure (SBP and DBP), pulse rate, white blood cell count, and low-density lipoprotein cholesterol. Models were adjusted for age, sex, race/ethnicity, body mass index (BMI), and poverty-income ratio (PIR).

Results A statistically significant interaction between blood lead concentration and PHQ-9 score was observed for mean SBP (β=-0.201, p=0.047). No significant interactions were observed for DBP, pulse rate, white blood cell count, or low-density lipoprotein cholesterol (all p>0.05).

Conclusions Depressive symptom burden modified the association between blood lead concentration and SBP but not the other biomarkers examined. These findings support considering environmental and psychosocial factors jointly when evaluating cardiovascular effects of lead exposure. Longitudinal studies are needed to confirm this interaction and clarify its underlying mechanisms.