Association between dietary salt intake and early renal impairment in elderly patients with type 2 diabetes: a cross-sectional study in central and southern China
4 affiliations
- 1Health Management Medicine Center, Third Xiangya Hospital of Central South University, Changsha, Hunan, China
- 2Nursing Department, Third Xiangya Hospital of Central South University, Changsha, Hunan, China
- 3Xiangya Nursing School, Third Xiangya Hospital of Central South University, Changsha, Hunan, China
- 4Department of Clinical Psychology, Third Xiangya Hospital of Central South University, Changsha, Hunan, China
Abstract
Objective This study aims to investigate the association between dietary salt intake and early renal impairment in elderly patients with type 2 diabetes.Design A retrospective cross-sectional study.Setting A health management centre of a large tertiary hospital in Hunan province, China, which is also one of the largest health management centres in central and southern China.Participants A total of 1027 elderly patients with type 2 diabetes participated in the study from 2017 to 2024.Primary and secondary outcome measures All participants completed a self-administered health assessment questionnaire before undergoing routine check-ups. Daily salt intake was calculated based on the 24-hour urinary sodium excretion. Early renal impairment was defined as urinary albumin to creatinine ratio (UACR) between 30 and 300 mg/g. Multivariable binary logistic regression and restricted cubic spline analyses assessed the association between dietary salt intake and early renal function impairment.Results Early renal impairment prevalence was 44.69%. Among 1027 participants, 678 (66.0%) were classified as G1 (estimated glomerular filtration rate (eGFR) ≥90 mL/min/1.73 m²) and 349 (34.0%) as G2 (eGFR 60–89 mL/min/1.73 m²). Age ≥75 years, higher dietary salt intake, systolic blood pressure, fasting blood glucose, preference for smoked and pickled foods and alcohol consumption were independently associated with early renal function impairment in elderly type 2 diabetes. After adjustment for potential confounders, participants with the highest salt intake (≥9.46 g/day) had a significantly higher risk of UACR positivity than those with the lowest intake (≤6.63 g/day) (OR=1.619, 95% CI 1.098 to 2.387, p=0.015). Each quartile increase in salt intake was associated with an approximately 11% increase in UACR (B=0.104, 95% CI 0.041 to 0.167, p=0.001). In analyses stratified by chronic kidney disease stage, the association was significant in the G1 subgroup (p=0.002) but not in the G2 subgroup (p=0.783). Using the median salt intake (8.10 g/day) as reference, a linear positive association was observed between dietary salt intake and UACR positivity.Conclusions In this cross-sectional study, high salt intake was independently associated with early renal impairment in elderly patients with type 2 diabetes after adjustment for available confounders. Higher salt intake corresponded to progressively higher UACR positivity, and no obvious threshold was observed in the restricted cubic spline analysis. However, the cross-sectional design precludes causal inference, and longitudinal studies are needed to confirm these findings.
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BibTeX
@article{zhu2026association,
title = {{Association between dietary salt intake and early renal impairment in elderly patients with type 2 diabetes: a cross-sectional study in central and southern China}},
author = {Xiao Zhu and Liang Wang and Hongyu Zhao and Jia Liu and Jingqiang Zhang},
journal = {BMJ Open},
year = {2026},
month = oct,
doi = {10.1136/bmjopen-2026-120858},
url = {https://bmjopen.bmj.com/lookup/doi/10.1136/bmjopen-2026-120858},
note = {CC BY-NC 4.0},
}
RIS
TY - JOUR
TI - Association between dietary salt intake and early renal impairment in elderly patients with type 2 diabetes: a cross-sectional study in central and southern China
AU - Xiao Zhu
AU - Liang Wang
AU - Hongyu Zhao
AU - Jia Liu
AU - Jingqiang Zhang
PY - 2026
DA - 2026/10/23
JO - BMJ Open
DO - 10.1136/bmjopen-2026-120858
UR - https://bmjopen.bmj.com/lookup/doi/10.1136/bmjopen-2026-120858
AB - Objective This study aims to investigate the association between dietary salt intake and early renal impairment in elderly patients with type 2 diabetes.Design A retrospective cross-sectional study.Setting A health management centre of a large tertiary hospital in Hunan province, China, which is also one of the largest health management centres in central and southern China.Participants A total of 1027 elderly patients with type 2 diabetes participated in the study from 2017 to 2024.Primary and secondary outcome measures All participants completed a self-administered health assessment questionnaire before undergoing routine check-ups. Daily salt intake was calculated based on the 24-hour urinary sodium excretion. Early renal impairment was defined as urinary albumin to creatinine ratio (UACR) between 30 and 300 mg/g. Multivariable binary logistic regression and restricted cubic spline analyses assessed the association between dietary salt intake and early renal function impairment.Results Early renal impairment prevalence was 44.69%. Among 1027 participants, 678 (66.0%) were classified as G1 (estimated glomerular filtration rate (eGFR) ≥90 mL/min/1.73 m²) and 349 (34.0%) as G2 (eGFR 60–89 mL/min/1.73 m²). Age ≥75 years, higher dietary salt intake, systolic blood pressure, fasting blood glucose, preference for smoked and pickled foods and alcohol consumption were independently associated with early renal function impairment in elderly type 2 diabetes. After adjustment for potential confounders, participants with the highest salt intake (≥9.46 g/day) had a significantly higher risk of UACR positivity than those with the lowest intake (≤6.63 g/day) (OR=1.619, 95% CI 1.098 to 2.387, p=0.015). Each quartile increase in salt intake was associated with an approximately 11% increase in UACR (B=0.104, 95% CI 0.041 to 0.167, p=0.001). In analyses stratified by chronic kidney disease stage, the association was significant in the G1 subgroup (p=0.002) but not in the G2 subgroup (p=0.783). Using the median salt intake (8.10 g/day) as reference, a linear positive association was observed between dietary salt intake and UACR positivity.Conclusions In this cross-sectional study, high salt intake was independently associated with early renal impairment in elderly patients with type 2 diabetes after adjustment for available confounders. Higher salt intake corresponded to progressively higher UACR positivity, and no obvious threshold was observed in the restricted cubic spline analysis. However, the cross-sectional design precludes causal inference, and longitudinal studies are needed to confirm these findings.
SN - 2044-6055
SN - 2044-6055
ER -