Association between dietary fiber intake and chronic kidney disease in adults with and without hypertension in the United States: a cross-sectional study of NHANES 2009–2020

While previous research has highlighted the potential advantages of increasing dietary fiber intake (DFI) for managing hypertension and chronic kidney disease (CKD), there is a gap in large-scale empirical studies examining the relationship between DFI and CKD among hypertensive and nonhypertensive cohorts independently. This study involved 22,871 participants sourced from the NHANES database spanning 2009 to 2020, who were divided into hypertensive (<i>n</i> = 9,861) and nonhypertensive (<i>n</i> = 13,010) groups. The analysis revealed a significant inverse correlation between DFI and CKD prevalence across the sample after adjusting for various covariates (OR = 0.98, 95% CI: 0.97–0.99, <i>p</i> = 0.001). Within the subset of hypertensive individuals, this inverse association mirrors the findings of the overall sample, indicating that a higher DFI was associated with a reduced occurrence of CKD (OR = 0.97, 95% CI: 0.96–0.99, <i>p</i> &lt; 0.001). However, this correlation was not detected in the nonhypertensive group (OR = 0.99, 95% CI: 0.98–1.01, <i>p</i> = 0.285). The RCS analysis further confirmed a pronounced nonlinear inverse relationship between DFI and CKD prevalence in both the entire cohort and the hypertensive group but not in the nonhypertensive group. Further scrutiny of the hypertensive group revealed that individuals with a higher DFI had 33% lower odds of CKD progression for the moderate risk level and 36% lower odds for the high to very high risk level. Subgroup analyses confirmed the consistency of these relationships across various demographics. In summary, this investigation revealed a significant inverse relationship between DFI and CKD prevalence in US adults with hypertension, a relationship not observed in nonhypertensive individuals.

既往研究已阐明增加膳食纤维摄入量（Dietary Fiber Intake, DFI）对高血压与慢性肾脏病（Chronic Kidney Disease, CKD）管理的潜在益处，但目前仍缺乏独立针对高血压与非高血压队列展开的、探讨DFI与CKD关联的大规模实证研究。本研究纳入2009至2020年美国国家健康与营养调查（NHANES）数据库中的22871名受试者，将其分为高血压组（n=9861）与非高血压组（n=13010）。校正各项混杂因素后，全队列分析显示DFI与CKD患病率呈显著负相关（比值比（Odds Ratio, OR）=0.98，95%置信区间（Confidence Interval, CI）：0.97~0.99，p=0.001）。在高血压亚队列中，该负相关关系与全队列结果一致，即DFI水平越高，CKD发生风险越低（OR=0.97，95%CI：0.96~0.99，p<0.001）。但在非高血压组中未观察到该关联（OR=0.99，95%CI：0.98~1.01，p=0.285）。限制性立方样条（Restricted Cubic Spline, RCS）分析进一步证实，全队列及高血压组中DFI与CKD患病率呈显著非线性负相关，而非高血压组则无此关联。对高血压组的进一步分析显示，在中等风险层级中，DFI水平较高者的CKD进展风险降低33%；在高至极高风险层级中，该风险降低36%。亚组分析证实，上述关联在不同人口学特征亚组中均保持稳定。综上，本研究表明，美国高血压成年人群的DFI水平与CKD患病率呈显著负相关，而该关联在非高血压人群中并未显现。