Mild Renal Dysfunction Among Turkish Adults: Prevalence and Its Association With Insulin Resistance

OBJECTIVE: To investigate the prevalence of mild renal
dysfunction and its association with insulin resistance (IR), metabolic syndrome (MS) or its components among Turkish adults.

METHODS: Serum creatinine concentrations were measured in
1048 male and female subjects. After excluding cases with diabetes mellitus, 933 participants of a representative cohort were studied cross-sectionally. Glomerular filtration rate (GFR) was estimated
based on serum creatinine concentrations using the Modification
of Diet in Renal Disease formula. GFR was divided into 3 categories constituting chronic kidney disease stages 2 and ³3. MS was
identified by modified criteria of the Adult Treatment Panel-III.

RESULTS: MS existed in 38.7% of the cohort. Mild renal dysfunction (estimated GFR 60 to 89.9 mL/min/1.73 m2) existed in 50% of
the study sample in both genders. Compared to the group with
normal GFR, in category II, age-adjusted estimates of body mass
index, homeostatic model assessment (HOMA) index, blood pressures, total, HDL-, LDL-cholesterol and serum proteins were all significantly elevated in both genders, as were apo B and log TSH in
women alone. Stated variables were also significantly and inversely correlated with GFR. Whereas MS was not significantly associated with GFR categories, nor with reduced GFR when controlled
for HOMA, HOMA –adjusted for MS as well as for sex, age and
systolic BP- was significantly associated with likelihood for reduced GFR.

CONCLUSION: Mild impairment of kidney function is very common in nondiabetic middle-aged and elderly adults, is associated
mainly with IR and related cardiovascular risk factors, in the absence of MS-related atherogenic dyslipidemia. IR is important even in
mild reduction in GFR, an action independent of central obesity-related components of MS.