Elevated Blood Pressure and its Association with Body Fat, Anthropometric Characteristics, and Dietary Intakes in a Sample of Lebanese Adolescents

Abstract

Background: Elevated blood pressure (EBP) in adolescents is an emerging public health issue, largely driven by increasing obesity levels and dietary and lifestyle shifts. Obesity is a key risk factor for EBP, mainly through central adiposity and insulin resistance. While body mass index (BMI) and waist circumference (WC) are commonly used as adiposity indicators, alternative measures like mid-upper arm (MUAC) and calf circumferences (CC) may be useful in resource-limited settings. In Lebanon and similar countries experiencing a nutrition transition, poor diets and high levels of physical inactivity further increase the risk for EBP, highlighting the need for early, and context-sensitive screening approaches.

Objective: This cross-sectional study aims to: (1) determine the prevalence of EBP in a sample of Lebanese adolescents; (2) examine the associations of EBP with anthropometric indicators—specifically BMI, WC, CC, and MUAC, and with body composition —; and (3) explore the relationship between lifestyle and dietary factors and EBP in this age group.

Methods: This cross-sectional study included 114 Lebanese adolescents aged 15–18 years old, recruited based on predefined inclusion criteria. Anthropometric measurements (including BMI, waist, mid-upper arm, and calf circumferences), body composition (via deuterium dilution and bioelectrical impedance analysis), and blood pressure were assessed following standardized procedures. Dietary intake was evaluated using a single 24-hour recall, and physical activity was assessed using an adapted questionnaire from the Global School-Based Student Health Survey (GSHS). Blood samples were collected to measure fasting blood glucose and lipid profiles. EBP was defined according to the International Diabetes Federation criteria (SBP ≥130 mm Hg and/or DBP of ≥85 mm Hg). Data were analyzed using SPSS, with logistic regression models used to examine associations between EBP and anthropometrics, lifestyle, and dietary factors. Results: The prevalence of EBP was approximately 18%. Based on descriptive analyses, WC, MUAC, and CC were significantly higher in participants with EBP compared to their peers. However, the significance for MUAC and CC was lost after adjusting for age and sex. In contrast, waist circumference remained a strong predictor of EBP even after adjustment for confounders (OR = 3.89; 95% CI: 1.28–11.78). Additionally, BMI showed a significant association with EBP, with obese participants having approximately four times higher odds of developing EBP compared to those with normal weight (OR = 3.75; 95% CI: 1.01–13.79). This significance was lost after adjusting for confounders. Importantly, the presence of EBP increased the odds of having metabolic syndrome (MetS) by 13-fold after adjusting for confounders (OR = 13.29; 95% CI: 1.75–100.65). Physical activity demonstrated a protective effect, even after adjusting for age, sex, and BMI (OR = 0.09; 95% CI: 0.01–0.91). No significant association was observed between dietary intake and elevated blood pressure. Conclusion: This study underscores the important role of central obesity (measured by WC) in predicting EBP among Lebanese adolescents, and highlights EBP as a strong independent predictor of the metabolic syndrome in this age group. It also showed that MUAC and CC emerged as promising, simple screening tools for EBP risk. Physical activity was found to have a protective effect against EBP, which aligns with existing literature supporting its cardiovascular benefits. While this study provides valuable insights, it is important to acknowledge certain limitations, including the small sample size and cross-sectional design, which limit the generalizability of the findings. Despite these constraints, the results highlight the need for larger, more comprehensive studies to confirm and expand upon these associations.