ASSOCIATIONS OF BODY MASS INDEX, AGE, AND GENDER WITH SYSTOLIC BLOOD PRESSURE AMONG U.S. ADULTS: NHANES 2021–2023

Abstract

Background: Systolic blood pressure (SBP) is a major determinant of cardiovascular disease risk and is influenced by demographic and physiological factors such as age, gender, and body mass index (BMI).

Objective: To examine the associations of BMI, age, and gender with systolic blood pressure among U.S. adults using nationally representative data.

Methods: A cross-sectional analysis was conducted using data from 5,805 adults aged 20 years and older from the National Health and Nutrition Examination Survey (NHANES) 2021–2023. Descriptive statistics summarized participant characteristics. Pearson correlation analysis assessed the relationship between BMI and SBP. Univariate and multiple linear regression models were applied to evaluate the associations of BMI, age, and gender with SBP. Additionally, binary logistic regression analysis was performed to examine the association of these variables with a categorical outcome. Statistical significance was set at p < 0.05.

Results: The mean age of participants was 53.85 years, and the mean BMI was 29.73 kg/m². The average systolic blood pressure was 122.87 mmHg. BMI showed a weak but statistically significant positive correlation with SBP (r = 0.027, p = 0.037). In multiple linear regression analysis, BMI (β = 0.087, p = 0.004), age (β = 0.404, p < 0.001), and gender (β = -4.21, p < 0.001) were significant predictors of SBP. Age demonstrated the strongest association, with SBP increasing with advancing age. Females had significantly lower SBP compared to males. The model explained approximately 16% of the variance in SBP (R² = 0.1626). In logistic regression analysis, age remained a significant predictor (OR = 1.07, p < 0.001), while BMI and gender were not significantly associated.

Conclusion: Age, gender, and BMI are important factors associated with systolic blood pressure among U.S. adults, with age showing the strongest influence. These findings highlight the importance of targeted monitoring and preventive strategies, particularly among older populations and males, to reduce the burden of hypertension and related cardiovascular risks