Analysis of correlation between dietary fiber intake and risk of diabetic kidney disease in adults with type 2 diabetes mellitus: results from the United States National Health and Nutrition Examination Surveys 2009–2018

Given the significant impact of diabetic kidney disease (DKD) on morbidity and mortality in patients with type 2 diabetes mellitus (T2DM) and the potential preventive role of dietary factors, particularly dietary fiber, this study aimed to investigate the relationship between dietary fiber intake and the risk of DKD in adults with T2DM. The medical records and other relevant data from patients with T2DM were retrieved from the United States National Health and Nutrition Examination Surveys (U.S. NHANES) from 2009 to 2018. Multivariate logistic regression and restricted cubic spline (RCS) regression were employed to investigate the relationship between dietary fiber intake and the risk of DKD in adult T2DM patients. The study involved 4,520 T2DM patients with a mean age of 59.16 years, consisting of 2,346 male patients (51.9%) and 2,174 female patients (48.1%). The prevalence of T2DM patients with DKD was 37.92% in the overall population. Regression analyses, after adjusting for confounders, showed that dietary fiber intake was negatively correlated with the prevalence of DKD. RCS analysis demonstrated a nonlinear negative correlation between the level of dietary fiber intake and the prevalence of DKD, with a threshold inflection point of 13.96 g/day. Subgroup analyses revealed that age, gender, race, smoking status, body mass index, hypertension, diabetes duration, glycosylated hemoglobin, and ACEI/ARB medication use did not significantly affect the negative correlations (<i>p</i> &gt; 0.05). Dietary fiber intake was negatively correlated with the prevalence of DKD in T2DM patients.