Alterations in Kidney Function in Overweight and Obese Children and Adolescents

Worldwide, the public health problem of obesity is increasing. The prevalence of overweight and obesity is extremely high in Mexico in both the adult and pediatric population (72% and 35%). Among adults, there are strong associations between obesity and kidney disease; however, there are few data available regarding such associations in adolescents and children.

Researchers in Guadalajara, Mexico, led by Fabiola Martin-del-Campo, LN, MSc, recently conducted a cross-sectional analysis designed to compare the frequency of renal damage according to the presence of overweight-obesity in the pediatric population. The study also sought to compare nutritional and biochemical risk factors according to the presence of kidney alterations. Results of the analysis were reported in the Journal of Renal Nutrition [2019;29(5):370-376].

The study cohort included 172 children and adolescents; 27% (n=42) were classified as normal weight, 32% (n=55) as overweight, and 41% (n=71) as obese. Participants in the obesity group had significantly higher proportion of family history of obesity and higher systolic blood pressure compared with the other two groups. In the group with obesity, there was a nonsignificant trend to higher birth weight, higher diastolic blood pressure, and more sedentary activities. There were no other differences observed regarding age, sex, and family history of diabetes, hypertension, or kidney disease

Biochemical Characteristics

Compared with controls, participants in the overweight and obesity groups had significantly higher prevalence of abdominal obesity (0% vs 69%), hypertension (19% vs 26%), hyperuricemia (11% vs 28%), hypertriglyceridemia (11% vs 47%), high low-density lipoprotein cholesterol (2% vs 8%), and low high-density lipoprotein cholesterol (2% vs 28%).

Those in the overweight and obesity groups had higher prevalence of risk factors for kidney disease than those in the normal weight group. Individual prevalence of risk factors such as dyslipidemia, hyperinsulinemia, and abdominal obesity was >60% in children and adolescents in the overweight and obesity groups.

There were no significant differences in serum creatinine, glomerular filtration rate (GFR), and albuminuria between the groups. However, the researchers did note that there was one case of decreased GFR as well as four cases of hyperfiltration in the obesity group, and one case of hyperfiltration in the overweight group. Microalbuminuria was present in four cases (none with hypertension); one case was in the overweight group and the other three were in the obesity group. Including both alterations in GFR and microalbuminuria, the frequency of kidney alterations was ~10% in the obesity group, 4% in the overweight group, and 0% in the normal weight group.

In multivariable analysis, there was a negative correlation between GFR and age, uric acid, and intake of monounsaturated fatty acid. Age and uric acid levels were also negatively correlated with albuminuria; sodium intake and protein intake had a positive correlation (P<.05 for all). In multivariant analysis, significant predictors of kidney alterations were higher body mass index and lower HDL cholesterol.

The researchers said, “In conclusion, kidney alterations were observed in 5.3% of the whole sample of children and adolescents of this sample. Such alterations were present only in subjects with overweight (3.6%) and obesity (9.9%), who additionally displayed several cardiometabolic and kidney disease risk factors more frequently than those with normal weight. Screening for kidney alterations in high-risk children and adolescents with overweight/obesity may be an excellent opportunity in helping to prevent the burden of kidney failure in adulthood.”

Takeaway Points

  1. Researchers in Mexico conducted a cross-sectional study to examine the frequency of renal damage in overweight/obese children and adolescents.
  2. Compared with subjects with normal weight, those with overweight/obesity had significantly higher abdominal obesity, hypertension, hypertriglyceridemia, high low-density lipoprotein cholesterol, low high-density lipoprotein cholesterol, hyperuricemia, and hyperinsulinemia.
  3. In multivariable analyses, kidney alterations were significantly predicted by higher body mass index and lower high-density lipoprotein cholesterol.