What is the normal blood glucose level in an 8-year-old child?

Normal Blood Glucose Levels in 8-Year-Old Children

Normal fasting blood glucose in an 8-year-old child is 90-180 mg/dL before meals and 100-180 mg/dL at bedtime/overnight, with target A1C levels of approximately 8%. 1

Age-Specific Blood Glucose Targets

The American Diabetes Association provides specific guidelines for blood glucose targets in children based on age groups:

School-age children (6-12 years):

• Before meals: 90-180 mg/dL (5.0-10.0 mmol/L)
• Bedtime/overnight: 100-180 mg/dL (5.6-10.0 mmol/L)
• Target A1C: 8% 1

These targets are higher than those for adolescents or adults due to important physiological and developmental considerations:

Rationale for Higher Targets in Children

1. Hypoglycemia vulnerability: School-age children have:

   • Immature counter-regulatory mechanisms
   • Often lack cognitive capacity to recognize and respond to hypoglycemic symptoms
   • A form of "hypoglycemic unawareness" common in children under 7 years 1

2. Developmental risks: Children younger than 5-6 years are at risk for permanent cognitive impairment after episodes of severe hypoglycemia, unlike adults 1

3. Lower risk of complications: Children have relatively low risk of diabetes complications prior to puberty 1

Normal Glucose Physiology in Children

Research in healthy children aged 2-8 years using continuous glucose monitoring shows:

• Mean sensor glucose: 5.3 ± 1.0 mmol/L (95 ± 18 mg/dL)
• 89% of values fall within 4-7.8 mmol/L (72-140 mg/dL)
• Only 2% of values exceed 7.8 mmol/L (140 mg/dL) 2

Abnormal Glucose Values

For diagnostic purposes, the following values are considered abnormal:

• Impaired fasting glucose (IFG): 100-125 mg/dL (5.6-6.9 mmol/L) 1, 3
• Impaired glucose tolerance (IGT): 2-hour post-glucose load of 140-199 mg/dL (7.8-11.0 mmol/L) 1, 3
• Diabetes diagnosis thresholds:
  • Fasting plasma glucose ≥126 mg/dL (7.0 mmol/L)
  • 2-hour plasma glucose ≥200 mg/dL (11.1 mmol/L) during OGTT
  • A1C ≥6.5% (48 mmol/mol)
  • Random plasma glucose ≥200 mg/dL (11.1 mmol/L) with classic symptoms 1

Clinical Implications

• Blood glucose targets should be modified in children with frequent hypoglycemia or hypoglycemia unawareness 1
• Postprandial blood glucose values should be measured when there is a discrepancy between preprandial blood glucose values and A1C levels 1
• The incidental discovery of hyperglycemia without classic symptoms does not necessarily indicate diabetes, especially in young children with acute illness who may experience "stress hyperglycemia" 1
• By approximately 72 hours of age, normal fasting blood glucose levels in infants reach normal child and adult values (3.5-5.5 mmol/L), but children have different responses to fasting compared to adults 4, 5

Important Considerations

• Younger children have a faster decrease in glucose levels during fasting than older children 4
• Approximately 18% of adolescents in the US have prediabetes, with higher prevalence in males and those with obesity 6
• Modern diabetes management technologies have made it more feasible to achieve excellent glycemic control while reducing the incidence of severe hypoglycemia 1

When monitoring blood glucose in children, it's essential to consider both the immediate risks of hypoglycemia and the long-term benefits of good glycemic control, with targets that are appropriate for the child's developmental stage.