Tangled relationship between insulin resistance and microalbuminuria in children with obesity

Table 1 Main studies on microalbuminuria in children with obesity

Ref.	Study design	Population	Main findings
Savino et al[44]	Case Control	One hundred seven OB Caucasian prepubertal and pubertal children and adolescents of both sexes (M 52, F 55). Fifty normal weight Caucasian children as control group (M 26, F 24)	A modest significant difference was seen in AER values, which were higher in the OB group, even if mostly within normal range. AER showed a positive correlation with central adiposity, insulin resistance indexes and hypertension
Sanad and Gharib[43]	Cross – Sectional	One hundred fifty prepubertal obese children. Exclusion criteria: fever, infections, renal diseases, LES, endocrine disorders, albuminuria associated with urinary tract infections	There were significant positive correlations between MA and BMI, WC, systolic and diastolic BP, TG and LDL-c levels, insulin resistance and fasting glucose level. In contrast, there was a negative correlation between MA and HDL-c levels (P < 0.01). No significant correlations of MA with age and sex were found (P > 0.05)
Csernus et al[45]	Case-Control	Eighty-six obese children. Seventy-nine normal weight children as a control group. children with secondary obesity were excluded	OB children with obesity had a significantly higher U-ACR and U-BMCR as compared to the normal weight children. OB children with no more than one of cardiovascular risk factors (e.g., hyperinsulinemia, fasting or post-prandial glucose, dyslipidemia and hypertension) had a significantly lower U-ACR than those with two or more features. U-ACR was positively correlated with body weight and with the fasting plasma glucose concentrations measured during the OGTT. U-ACR was increased in OB children with hypercholesterolemia. No association of U-ACR with TG and HDL-c levels was found
Goknar et al[30]	Case-Control	Eighty-four OB individuals aged 4-16 yr as study (case) group. Sixty-four normotensive healthy children as control group	No statistically significant differences were found in urine microalbumin/creatinine (P = 0.740)
Hirschler et al[12]	Retrospective Study	One thousand five hundred sixty-four children aged 5-14 yr, 220/1564 OB (14.1%), 300/1564 OW (19.2%), 1044/1564 (66.7%) normal weight, 318/1564 (20.3%) central OB	U-ACR decreased with increasing z-BMI for boys and girls. Median ACR and urinary albumin levels were significantly higher in normal weight children than in OW/OB children. Median ACR and urinary albumin levels was higher in OB girls than in OB boys
Radhakishun et al[28]	Retrospective	Four hundred eight OB children aged 3-19 yr, 50 % males	A low prevalence of MA (2.7%) was found. All subjects with MA were obese
Oz-Sig et al[33]	Retrospective	One hundred and five obese children (M 39) aged 4-18 yr. The cohort was divided into three groups as solely obese, with metabolic syndrome and with type 2 diabetes. MA was tested in 24 h collected urine (MA: 30-300 mg)	MA was significantly higher in type 2 diabetic group; statistical significance was reached in the group with metabolic syndrome and type 2 diabetic group. MA was not detected in the solely obese group
Lurbe et al[32]	Retrospective	One hundred and thirty-four OB children aged 9-18 yr. Obesity: z score > 2, Moderate obesity: z score 2-2.5. Severe obesity: z score > 2.5. UAE was measured in the first voiding urine of the morning	No differences between different groups of obesity degree were found. Increased UAE was linked to fasting Insulin HOMA Index, higher WC, and TG levels
Cho et al[15]	Retrospective	One thousand four hundred and fifty-nine adolescents aged 12-18 yr	MA was detected in 3.6% of subjects (53/1459). The Height z score of the MA group was greater than that of the NA group. The Weight z score of the MA group did not differ from that of NA group. The MA group had a lower BMI z score. MA group had higher HDL-c and lower TG levels. No significant differences in BP, fasting glucose, total cholesterol, and LDL levels were reported. UACR was associated with younger age, lower weight z score, lower BMI z score, lower W/Hr, but not with the height z score. UACR was associated with higher HDL level and lower TG values
Burgert et al[34]	Cohort Study	Two hundred seventy-seven children and adolescents	MA was found in 10.1 % of subjects (28/277). No significant differences between the two groups (MA e NA) in term of the anthropometrical and common cardiovascular risk factors were reported. Subjects with MA had higher plasma glucose and insulin levels during OGTT
Nguyen et al[29]	Cross Sectional	Two thousand five hundred fifteen adolescents aged 12-19 yr. 310/2515 children with BMI > 95 pc.	MA was detected in 8.9% of the study population. UACR girls was significantly higher in girls than in boys. MA was prevalent among NON-OW adolescents. Similarly, MA was prevalent among adolescents without abdominal obesity, and without insulin resistance
Martin-Del-Campo et al[38]	Cross Sectional	One hundred seventy-two children and adolescents aged 6-16 yr, 46/172 (27%) normal weight, 55/172 (32%) overweight, 71/172 (41%) obesity	MA was observed in children with OW (3.6%) and with OB (9.9%) more than in normal weight children

AER: Albumin excretion rate; BMI: Body mass index; HDL-c: High-density lipoprotein- cholesterol; LDL-c: Low-density lipoprotein- cholesterol; MA: Microalbuminuria; NA: Normal albuminuria; OB: obese; OGTT: Oral glucose tolerance test; OW: overweight; TG: Triglycerides;U-ACR: Urinary albumin/creatinine ratio; UAE: Urinary albumin excretion; U-BMCR: Urinary beta-2-microglobulin/creatinine ratio; WC: Waist circumference; W/Hr: waist-to-height ratio.