Fasting blood sugar reference ranges
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Fasting Blood Sugar Reference Ranges in Healthy Adults
Fasting blood sugar (FBS) reference ranges are essential for diagnosing and managing diabetes and other metabolic conditions. These ranges can vary based on population, age, and other factors.
Standard Fasting Blood Sugar Reference Ranges
Most studies in healthy adults report fasting blood sugar reference intervals between 70 and 100 mg/dL (3.9–5.6 mmol/L) as typical for non-diabetic individuals 157. For example, a study in Kerala, India, found a mean fasting blood glucose of about 81 mg/dL, with no significant difference between males and females . Similarly, early research in the U.S. reported a range of 70–95 mg/dL, with an average of 81.6 mg/dL .
Population and Ethnic Differences in Fasting Blood Sugar
Reference ranges can differ by population. In Sudan, healthy adults had a lower mean fasting blood glucose of 74.3 mg/dL, with a reference range from 60.5 to 88.1 mg/dL, which is lower than many international standards . This highlights the importance of establishing local reference intervals for accurate diagnosis 12.
Age-Related Variations in Fasting Blood Sugar
Fasting blood sugar levels tend to increase with age. In the Kerala study, the highest mean fasting blood glucose was observed in the 50–59 year age group . Research from China on people aged 90 and above found that desirable fasting plasma glucose levels were below 6.15 mmol/L (about 110.7 mg/dL), with higher values considered borderline or high . These findings suggest that reference intervals may need adjustment for older adults 110.
Fasting Blood Sugar in Children and Across the Lifespan
Fasting glucose reference ranges also vary with age in children and adolescents. Studies show strong age-dependent variation, and age-specific reference ranges are recommended for children and adolescents to improve risk prediction for future glycemic issues .
Fasting Blood Sugar Targets in Diabetes Management
For people with type 2 diabetes, optimal fasting blood glucose targets are often set lower to achieve good long-term control. Recent clinical trials in China suggest that a fasting blood glucose target of 3.9–6.1 mmol/L (about 70–110 mg/dL) is optimal for most patients, balancing glycemic control and risk of hypoglycemia 36. Lower targets may be considered for those at low risk of hypoglycemia 36.
Impaired Fasting Glucose and Risk Thresholds
There is no clear threshold for impaired fasting glucose (IFG), as cardiovascular and diabetes risk increase continuously with rising fasting glucose. Some studies suggest that using a lower limit, such as 5.8 mmol/L (about 104 mg/dL), may better identify individuals at risk for future diabetes .
Conclusion
Fasting blood sugar reference ranges for healthy adults are generally between 70 and 100 mg/dL, but these can vary by population, age, and health status 125710. Local reference intervals and age-specific ranges are important for accurate diagnosis and risk assessment 12910. For diabetes management, targets are often set within or slightly below this range to optimize outcomes 36. Continuous monitoring and adjustment of these ranges are necessary to reflect population-specific and age-related differences.
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