Insulin Resistance Risk Much Higher for Kids With Obesity

SEATTLE — Insulin resistance and several other cardiometabolic risk factors were far more common in kids with obesity, according to late-breaking findings presented here.

In a cross-sectional study of adolescents ages 10-19 years, the average plasma insulin levels of kids with obesity or overweight were 24.8 μU/mL and 17.4 μU/mL, respectively, compared with 9.28 μU/mL in normal weight kids, said Namrata Chhabra, MBBS, MD, MHPE, PhD, of the American University of Antigua College of Medicine.

This equated to 59% and 42% of kids with obesity or overweight having plasma insulin levels higher than normal versus only 14% of kids of a normal weight, she explained at the American Association of Clinical Endocrinology (AACE) annual meeting.

Plasma glucose levels — although all “well within the normal range” — were also significantly higher in kids with obesity, averaging 85.15 mg/dL, while this level was 81.76 mg/dL for overweight kids and 77.46 mg/dL for normal weight kids. The same pattern was also seen for average HDL levels and the ratio of LDL to HDL cholesterol.

Plasma glucose levels and waist-to-hip ratio were higher across the board in pubertal kids in each weight category compared with post-pubertal children. “Puberty was an additional risk factor in these individuals,” Chhabra said.

Following a similar pattern, HOMA-IR — a marker of insulin resistance — was 4.4 and 3.6 in kids with obesity or overweight compared with a levels of 2.7 in normal weight kids. A total of 42% of kids with obesity had insulin resistance, while 27% of overweight and 11% of normal weight kids did.

On top of that, C-reactive protein and highly sensitive CRP levels — markers of inflammation — were both several times higher in kids with obesity:

• Mean CRP levels: 9 mg/L for obesity, 4.3 mg/L for overweight, 0.78 mg/L for normal weight
• Mean HsCRP levels: 3.175 mg/L, 1.75 mg/L, 0.74 mg/L, respectively

A greater proportion of kids with obesity also exhibited cutaneous markers of insulin resistance, like acanthosis nigricans (58% vs 39% for overweight vs 14% for normal weight).

Kids with obesity and insulin resistance also had the highest levels of triglycerides and alanine transaminase (ALT).

Insulin resistance was also found to be significantly associated with a few anthropometric measures: gender, Tanner stage, acanthosis nigricans, waist circumference, and waist-to-hip ratio.

Taking that one step further, waist circumference was closely linked with higher CRP, HsCRP, insulin resistance, and triglycerides.

This is a particularly important finding because it underscores the value of using waist circumference to target kids most at risk, Chhabra suggested.

Metabolic syndrome was present in 26% of those with obesity, 11% of those with overweight, as well as 2.8% of normal weight kids. “Since the findings were there in normal weight individuals, that shows BMI has some problems,” she said, “because it is a good marker, but not as effective as a marker in regards to risk for cardiovascular disease is concerned.”

“BMI, along with waist circumference, and waist-to-hip ratio — these are better predictors of cardiovascular disease risk in comparison to BMI alone,” Chhabra said.

“We have seen BMIs association with insulin resistance…but alone, it is not a good predictor, so we should waist circumference, as well as waist-to-hip ratio to complete the list,” she added, “BMI is not a predictor of adiposity because it includes muscle mass as well. Central adiposity has been associated more with insulin resistance, which is why waist circumference and waist-to-hip ratio need to be included.”

“Waist-to-hip ratio is the best option [to use],” Chhabra stated.

A total of 150 adolescents were recruited for the study. According to the exclusion criteria, none of the participants could have endocrine disorders, acute or chronic infectious disease, liver or kidney diseases, corticosteroid or other medications affecting glucose metabolism, or be prepubertal.

Obesity was considered a BMI over 30, overweight was over 25 to 29.9, and normal weight was 24.9 or below. “Low risk” waist circumferences were considered below 80 cm for female and below 90 cm for males.

Of kids with markers of insulin resistance, 36% had a family history, 54% followed a non-vegetarian diet, and 34% had sleep disorders. This underscores the overlay of genetic and environmental factors playing into insulin resistance, Chhabra said.

“Insulin resistance, or those at risk of developing insulin resistance, should further be screened for the presence of components of metabolic syndrome,” she advised. “Clinical evaluations of insulin resistance and metabolic syndrome should be supported with early lifestyle modifications and therapeutic interventions.”