Sex-specific trajectories of blood pressure and pulse pressure across body mass index categories: a descriptive study based on 13-year health checkup data

The combined effects of aging, sex, and body mass index (BMI) on blood pressure trajectories remain incompletely characterized in large-scale populations. The aim was to describe age-related blood pressure trajectories according to sex and BMI, as understanding these patterns is essential to improve risk stratification and develop preventive strategies for hypertension and cardiovascular diseases. This study included individuals who underwent annual physical examinations at Kagoshima Kouseiren Hospital in 2007-2019 (n = 213058). Systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate, and BMI measurements were retrospectively analyzed, and age-related changes were visualized using locally weighted scatterplot smoothing (LOWESS). Analyses were stratified by sex and BMI category (underweight, normal weight, class 1 obesity, and class 2 obesity or higher). Higher BMI levels were consistently accompanied by higher SBP, DBP, pulse pressure, and heart rate in both sexes. The LOWESS curves revealed that SBP increased steadily with age, particularly in individuals with obesity, whereas DBP increased until middle age before plateauing or declining. Consequently, the pulse pressure widened with age, especially in men with obesity. Heart rates remained stable but were consistently higher in women and obese participants. The age-related divergence between SBP and DBP was more pronounced in men and in individuals with a higher BMI. Ultimately, distinct age-related blood pressure and pulse pressure changes varied by sex and BMI category, and obesity was associated with accelerated SBP and pulse pressure trajectories, suggesting features consistent with earlier vascular aging. Adopting sex- and BMI-specific approaches may help inform blood pressure monitoring and prevention.