The hidden curve: exploring the inverse U-Shaped association between NLR and hypertension in obesity

The Neutrophil-to-Lymphocyte Ratio (NLR) is associated with hypertension, and obesity is a significant risk factor for hypertension. However, the relationship between NLR and overweight and obese hypertension remains unclear. This study was a cross-sectional analysis of data from 40,623 participants with body mass index (BMI) ≥ 24 kg/m 2 who were health screened from January 2018 to December 2023 at Henan Provincial People’s Hospital. Participants were divided into groups with hypertension and those without hypertension, according to hypertension diagnostic criteria. The NLR, our dependent variable, was determined using the equation [neutrophil/ lymphocyte]. We explored the association between NLR and hypertension in overweight and obese individuals through multivariate logistic regression, generalized additive models, smoothed curve fitting, analysis of threshold effects, and subgroup analysis. After adjusting for other covariates, elevated NLR was associated with higher hypertension prevalence [OR = 1.27, 95% CI = 1.20–1.36; P < 0.001; P for trend < 0.001, comparing Q4 with Q1 in model II]. Smoothed curve fitting revealed an inverse U-shaped association between NLR and hypertension prevalence, with lower prevalence observed at NLR values greater than 2.91. Subgroup analyses showed similar association patterns across gender, age, BMI, and occupational subgroups, though statistical power to detect interactions was limited. This study demonstrated an inverted U-shaped association between NLR and hypertension in overweight and obese Chinese adults, with an inflection point at 2.91. However, as a single-center health screening study without external validation, generalisability to community or clinical populations is uncertain. Multi-center validation studies are needed. not applicable.