Synergistic Effects of Sleep-Depression Comorbidity on Cardiovascular Health: A Gender- and Age-Stratified Analysis Based on NHANES Data

Background Cardiovascular disease (CVD) is a major global health threat, and the comorbidity of sleep disorders and depression may further exacerbate cardiovascular risk, with this association being influenced by gender, age, and social factors. This study utilized NHANES 2013–2018 data to evaluate the association between comorbidity and cardiovascular health indicators, quantify synergistic effects, and analyze gender and age differences. Methods Participants aged ≥ 18 years with complete data from NHANES 2013–2018 were included, excluding those with severe cognitive impairment. Comorbidity status was assessed using sleep questionnaires and the Patient Health Questionnaire (PHQ). Blood pressure, obesity indices, blood lipids, and high-sensitivity C-reactive protein (HSCRP) were measured. Statistical analyses were performed using R software, including descriptive statistics, multivariate logistic regression, and interaction tests. Results The comorbidity group had higher mean age, greater proportion of females, and significantly higher prevalence of hypertension, obesity, and HSCRP levels compared to the non-comorbidity group. Multivariate regression showed that comorbidity had significantly stronger effects on cardiovascular risk than either condition alone (e.g., hypertension risk in the comorbidity group was 2.89 times that of the normal group). Gender stratification revealed stronger associations in females, while age stratification showed increasing risk with age. Elevated HSCRP levels in the comorbidity group suggested inflammatory response as a key mechanism. Conclusion Sleep-depression comorbidity exhibits significant synergistic detrimental effects on cardiovascular health, with higher risks than either condition alone, particularly in females and older adults, with inflammatory response being an important underlying mechanism.