Dietary iron intake is nonlinearly associated with the risk of diabetic retinopathy in adults with type 2 diabetes

Abstract Objective To elucidate the association between dietary iron intake and diabetic retinopathy (DR) in type 2 diabetes (T2D) patients. Methods Participants from the National Health and Nutrition Examination Survey (NHANES) 2005–2008 aged over 40 years with T2D were included. Dietary iron intak...

Full description

Saved in:
Bibliographic Details
Main Authors: Xiaoyun Chen, Yihang Fu, Hongyu Si, Wenfei Li, Weimin Yang, Wei Xiao
Format: Article
Language:English
Published: BMC 2025-04-01
Series:BMC Endocrine Disorders
Subjects:
Online Access:https://doi.org/10.1186/s12902-025-01926-z
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850181903945039872
author Xiaoyun Chen
Yihang Fu
Hongyu Si
Wenfei Li
Weimin Yang
Wei Xiao
author_facet Xiaoyun Chen
Yihang Fu
Hongyu Si
Wenfei Li
Weimin Yang
Wei Xiao
author_sort Xiaoyun Chen
collection DOAJ
description Abstract Objective To elucidate the association between dietary iron intake and diabetic retinopathy (DR) in type 2 diabetes (T2D) patients. Methods Participants from the National Health and Nutrition Examination Survey (NHANES) 2005–2008 aged over 40 years with T2D were included. Dietary iron intake was estimated from standardised questionnaires. The presence of DR and vision-threatening DR (VTDR) was determined through retinal imaging. We used logistic regression to assess the relationship between iron intake and DR, and restricted cubic splines to reveal nonlinear links. Results The study enrolled 1172 T2D adults. We found significant nonlinear associations between dietary iron intake and DR among females (P = 0.023), but not in males (P = 0.490). Compared with the lowest quartile of iron intake, the third quartile (13.2–18.1 mg/d) yielded significantly lower odds of developing DR (odds ratio [OR], 0.59; 95% CI, 0.39–0.90) and VTDR (OR, 0.42; 95% CI, 0.19–0.94). Stratified logistic analyses showed that medium-high iron intake was associated with lower risks of DR in females (OR, 0.44; 95% CI, 0.24–0.81), non-Hispanic Blacks (OR, 0.38; 95% CI, 0.17–0.85), and individuals with obesity (OR, 0.45; 95% CI, 0.25–0.82), high HbA1c (OR, 0.56; 95% CI, 0.34–0.93), long diabetes duration (OR, 0.40; 95% CI, 0.21–0.76) or low blood haemoglobin (OR, 0.17; 95% CI, 0.05–0.60). Conclusion Dietary iron intake was nonlinearly negatively associated with the prevalence of DR and VTDR, showing protective effect against retinopathy of medium-high iron intake in T2D patients. Such associations significantly vary by multiple factors such as age, ethnicity, obesity and glycaemic control.
format Article
id doaj-art-908b3495c8a34d9f90a1dde13887f746
institution OA Journals
issn 1472-6823
language English
publishDate 2025-04-01
publisher BMC
record_format Article
series BMC Endocrine Disorders
spelling doaj-art-908b3495c8a34d9f90a1dde13887f7462025-08-20T02:17:47ZengBMCBMC Endocrine Disorders1472-68232025-04-0125111110.1186/s12902-025-01926-zDietary iron intake is nonlinearly associated with the risk of diabetic retinopathy in adults with type 2 diabetesXiaoyun Chen0Yihang Fu1Hongyu Si2Wenfei Li3Weimin Yang4Wei Xiao5State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Centre, Guangdong Provincial Key Laboratory of Ophthalmology and Vision Science, Guangdong Provincial Clinical Research Centre for Ocular Diseases, Sun Yat- Sen UniversityState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Centre, Guangdong Provincial Key Laboratory of Ophthalmology and Vision Science, Guangdong Provincial Clinical Research Centre for Ocular Diseases, Sun Yat- Sen UniversityState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Centre, Guangdong Provincial Key Laboratory of Ophthalmology and Vision Science, Guangdong Provincial Clinical Research Centre for Ocular Diseases, Sun Yat- Sen UniversityState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Centre, Guangdong Provincial Key Laboratory of Ophthalmology and Vision Science, Guangdong Provincial Clinical Research Centre for Ocular Diseases, Sun Yat- Sen UniversityState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Centre, Guangdong Provincial Key Laboratory of Ophthalmology and Vision Science, Guangdong Provincial Clinical Research Centre for Ocular Diseases, Sun Yat- Sen UniversityState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Centre, Guangdong Provincial Key Laboratory of Ophthalmology and Vision Science, Guangdong Provincial Clinical Research Centre for Ocular Diseases, Sun Yat- Sen UniversityAbstract Objective To elucidate the association between dietary iron intake and diabetic retinopathy (DR) in type 2 diabetes (T2D) patients. Methods Participants from the National Health and Nutrition Examination Survey (NHANES) 2005–2008 aged over 40 years with T2D were included. Dietary iron intake was estimated from standardised questionnaires. The presence of DR and vision-threatening DR (VTDR) was determined through retinal imaging. We used logistic regression to assess the relationship between iron intake and DR, and restricted cubic splines to reveal nonlinear links. Results The study enrolled 1172 T2D adults. We found significant nonlinear associations between dietary iron intake and DR among females (P = 0.023), but not in males (P = 0.490). Compared with the lowest quartile of iron intake, the third quartile (13.2–18.1 mg/d) yielded significantly lower odds of developing DR (odds ratio [OR], 0.59; 95% CI, 0.39–0.90) and VTDR (OR, 0.42; 95% CI, 0.19–0.94). Stratified logistic analyses showed that medium-high iron intake was associated with lower risks of DR in females (OR, 0.44; 95% CI, 0.24–0.81), non-Hispanic Blacks (OR, 0.38; 95% CI, 0.17–0.85), and individuals with obesity (OR, 0.45; 95% CI, 0.25–0.82), high HbA1c (OR, 0.56; 95% CI, 0.34–0.93), long diabetes duration (OR, 0.40; 95% CI, 0.21–0.76) or low blood haemoglobin (OR, 0.17; 95% CI, 0.05–0.60). Conclusion Dietary iron intake was nonlinearly negatively associated with the prevalence of DR and VTDR, showing protective effect against retinopathy of medium-high iron intake in T2D patients. Such associations significantly vary by multiple factors such as age, ethnicity, obesity and glycaemic control.https://doi.org/10.1186/s12902-025-01926-zDiabetic retinopathyVision-threatening diabetic retinopathyDietary iron intakeNHANES
spellingShingle Xiaoyun Chen
Yihang Fu
Hongyu Si
Wenfei Li
Weimin Yang
Wei Xiao
Dietary iron intake is nonlinearly associated with the risk of diabetic retinopathy in adults with type 2 diabetes
BMC Endocrine Disorders
Diabetic retinopathy
Vision-threatening diabetic retinopathy
Dietary iron intake
NHANES
title Dietary iron intake is nonlinearly associated with the risk of diabetic retinopathy in adults with type 2 diabetes
title_full Dietary iron intake is nonlinearly associated with the risk of diabetic retinopathy in adults with type 2 diabetes
title_fullStr Dietary iron intake is nonlinearly associated with the risk of diabetic retinopathy in adults with type 2 diabetes
title_full_unstemmed Dietary iron intake is nonlinearly associated with the risk of diabetic retinopathy in adults with type 2 diabetes
title_short Dietary iron intake is nonlinearly associated with the risk of diabetic retinopathy in adults with type 2 diabetes
title_sort dietary iron intake is nonlinearly associated with the risk of diabetic retinopathy in adults with type 2 diabetes
topic Diabetic retinopathy
Vision-threatening diabetic retinopathy
Dietary iron intake
NHANES
url https://doi.org/10.1186/s12902-025-01926-z
work_keys_str_mv AT xiaoyunchen dietaryironintakeisnonlinearlyassociatedwiththeriskofdiabeticretinopathyinadultswithtype2diabetes
AT yihangfu dietaryironintakeisnonlinearlyassociatedwiththeriskofdiabeticretinopathyinadultswithtype2diabetes
AT hongyusi dietaryironintakeisnonlinearlyassociatedwiththeriskofdiabeticretinopathyinadultswithtype2diabetes
AT wenfeili dietaryironintakeisnonlinearlyassociatedwiththeriskofdiabeticretinopathyinadultswithtype2diabetes
AT weiminyang dietaryironintakeisnonlinearlyassociatedwiththeriskofdiabeticretinopathyinadultswithtype2diabetes
AT weixiao dietaryironintakeisnonlinearlyassociatedwiththeriskofdiabeticretinopathyinadultswithtype2diabetes