Correlation between hemoglobin levels and cardiovascular disease in the adult American population: a cross-sectional study NHANES 2001 - 2018

Objective: To explore the relationship between hemoglobin levels and cardiovascular disease among American adults. Methods: This cross-sectional study utilized data from the National Health and Nutrition Examination Survey (NHANES) from 2001 to 2018. Cardiovascular disease was the dependent variable, and hemoglobin levels were the independent variable. Multivariate regression was used to assess the relationship between the independent and dependent variables, and subgroup analyses were conducted to ensure the stability of the results. Smooth curve fitting was employed to evaluate the non-linear relationship between hemoglobin levels and cardiovascular disease. Results: In multiple regression analysis, when adjusted for gender, age, and race, hemoglobin level was negatively correlated with the occurrence of heart failure, coronary heart disease, and stroke (p < 0.05). When adjusted for variables such as age, gender, race, education level, marital status, diabetes, smoking history, hypertension, hypercholesterolemia, and BMI, hemoglobin level was only negatively correlated with the occurrence of heart failure (p < 0.01). After dividing the hemoglobin values into five groups, compared with Q0, Q4 had a more significant negative correlation with heart failure and stroke. Threshold effect analysis showed that when the hemoglobin level was less than 16 g/dl, the higher the value, the lower the possibility of heart failure; when the hemoglobin value was less than 11 g/dl, the higher the value, the lower the incidence of stroke. Conclusion: Hemoglobin level is negatively correlated with the incidence of heart failure and stroke, and the relationship between coronary heart disease and angina pectoris is not significant.