Association between hypertension and dietary inflammatory index among adults: a cross-sectional study in Hainan, China

Abstract

Background Hypertension (HTN) affects 31.6% of Chinese adults and contributes to cardiovascular and cerebrovascular diseases through chronic inflammation. Pro-inflammatory diets, measured by the Dietary Inflammatory Index (DII), have been associated with increased HTN risk. However, evidence from tropical regions remains limited. As China’s only tropical province, Hainan has distinctive dietary patterns shaped by its geographic and climatic characteristics. This study aimed to examine the association between the DII and HTN among adults in Hainan to identify high-risk dietary patterns and inform targeted prevention strategies. Methods A cross-sectional study was conducted between 2020 and 2022 using a multistage sampling design to assess dietary intake among adults in Hainan. Data included demographic characteristics, height and weight, blood pressure assessments, and three-day dietary recalls. Quantile regression models were applied to evaluate the association between the DII and HTN. Subgroup analyses explored potential effect. Results A total of 826 adults were included, including 359 men (43.5%) and 467 women (56.5%). In unadjusted quantile regression, only new-onset HTN showed a significant inverse association with DII compared to normal blood pressure, confined to the median quantile (β = −0.96, 95% CI: −1.89 to −0.04; p = 0.040). However, this association was attenuated after adjustment for confounders and was no longer statistically significant (adjusted p > 0.05). Subgroup analyses revealed DII values were less likely to be at the median among female and Han Chinese with incident HTN, and among hypertensives aged 34–54 years, whereas in the 55–64 age group, those with incident HTN and no prior history were less likely to fall at the lower end of the DII distribution. No significant associations were found in males, ethnic minorities, or across occupational physical activity intensity categories. Conclusion This study suggests a potential relationship between dietary inflammatory potential and blood pressure in Hainan adults. No significant association persisted after full adjustment; however, an association between DII and new-onset HTN was observed at the median quantile in unadjusted models. Consistent trends in subgroup explorations indicate that pro-inflammatory dietary patterns may be associated with elevated blood pressure in specific populations, such as females, Han Chinese, and adults aged 34–64 years.