Association between serum ferritin and kidney function according to the presence of diabetes or hypertension
Dept. of Public Health/박사
Objective The prevalence of chronic kidney disease has been increasing according to the increase of the chronic disease and the elderly population. Serum ferritin is an acute phase reactant in infection, inflammation, malignancy and chronic disease as well as a biomarker on iron storage status. Diabetes and hypertension are risk factors of progression of chronic kidney disease. Studies on associations between serum ferritin and chronic kidney disease have been performed in the chronic kidney disease patients. However, effects of diabetes and hypertension on the association between serum ferritin and kidney function have not be studied especially in the general population. The purpose of this study was to investigate the association between serum ferritin and kidney function and to examine the effects of the diabetes and hypertension on the association using a nationally representative sample. MethodsStudy dataset was from the Korean National Health and Nutritional Examination Survey (KNHANES) conducted by Korea Centers for Disease and Control (KCDC) from 2008 to 2010. The numbers of final participants were 14,848 subjects (7,143 men and 7,705 women) from 20,948 participants aged 20 to 79 years. All statistical analyses were performed separately for three groups with men, premenopausal, and postmenopausal women. Descriptive statistics were presented as mean with standard deviation, medians with interquartile ranges, or frequency with percentage. Correlation analysis between serum ferritin, estimated Glomerular Filtration (eGFR) and other laboratory parameters were conducted. Multiple linear regression analysis was conducted to examine the association between the log-transformed serum ferritin and eGFR by the presence of diabetes or hypertension. An eGFR was calculated using the abbreviated equation from the Modification of Diet in Renal Disease (MDRD) study.ResultsThe median levels with interquartile ranges of serum ferritin were 100.4 (66.2, 155.1) in men, 34.9 (23.6, 52.5) in premenopausal women, and 58.6 (39.8, 86.8) in postmenopausal women, respectively. The means with standard deviation of eGFR in men, premenopausal, and postmenopausal women were 86.4±45.4, 96.1±16.7, and 83.4±17.0, respectively. A significant positive association between serum ferritin ad eGFR was found in men (β=1.06, p<0.001), but positive associations with borderline significance were found in premenopausal (β=0.85, p=0.080) and postmenopausal women (β=0.73, p=0.099). The association between serum ferritin and eGFR was stronger in men with diabetic men (β=2.59, p=0.005) than in non-diabetic men (β=0.77, p=0.005). However, no significant association between serum ferritin and eGFR by the presence of diabetes was observed in the premenopausal and postmenopausal women. The association between serum ferritin and eGFR was stronger in hypertensive men (β=1.40, p=0.005) than in normotensive men (β=0.84, p=0.007). In premenopausal women, however, the association between serum ferritin and eGFR was qualitatively changed from negative in normotensive group (β=1.11, p=0.028) to negative hypertensive group (β=-3.45, p=0.070). Conclusion Diabetes may strengthen the association between serum ferritin and eGFR in men, but not in premenopausal and postmenopausal women. Hypertension may strengthen the association between serum ferritin and eGFR in men, and may qualitatively modify the association between serum ferritin and eGFR in premenopausal women. Our findings suggest that the association between serum ferritin and eGFR may vary by the systemic disease such as diabetes and hypertension. A deliberate consideration will be required on the interpretation of the association between serum ferritin and eGFR in the general population.