Diabetes Pathophysiology

Diabetes Mellitus

Group of diseases characterized by prolonged high blood glucose concentrations

Hyperglycemia

High blood glucose caused by defects in insulin secretion, insulin action, or both

Insulin

Peptide hormone from pancreatic beta-cells that promotes glucose uptake into muscle and fat, lowering blood glucose

Glucagon

Peptide hormone from pancreatic alpha-cells that triggers glycogenolysis in the liver, increasing blood glucose

Glucocorticoids

Steroid hormones that increase and maintain blood glucose by stimulating gluconeogenesis in the liver

Pre-Diabetes

Stage of impaired glucose homeostasis with elevated risk for type 2 diabetes and CVD

Type 1 Diabetes

Pancreatic beta-cell destruction leading to absolute insulin deficiency

Type 2 Diabetes

Combination of insulin resistance and beta-cell failure

Gestational Diabetes

Diabetes diagnosed during pregnancy

Type 1 Diabetes Prevalence

5–10% of people with diabetes

Type 1 Diabetes Risk Factors

Family history, genetics, young age (children, teens, young adults)

Type 2 Diabetes/Prediabetes Risk Factors

Overweight, older age, family history, physical inactivity, history of gestational diabetes, non-alcoholic fatty liver disease

Sugar Causes Diabetes Myth

Consuming sugar alone does not cause diabetes; focus on risk factors and lifestyle

Diabetes Screening USPSTF

Adults 35–70 with overweight or obesity

ADA Screening Recommendation

Adults overweight with risk factors, screening may start before age 35

Gestational Diabetes Follow-Up

Screen once every 3 years after diagnosis

Prediabetes Diagnosis FPG

100–125 mg/dL after ≥8-hour fast

Prediabetes Diagnosis OGTT

2-hour post 75g glucose 140–199 mg/dL

Prediabetes Diagnosis HbA1c

5.7–6.4%

Diabetes Diagnosis HbA1c

≥6.5%

Diabetes Diagnosis FPG

≥126 mg/dL after ≥8-hour fast

Diabetes Diagnosis OGTT

2-hour post 75g glucose ≥200 mg/dL

Random Plasma Glucose Diagnostic

≥200 mg/dL with classic hyperglycemia symptoms

Fasting Plasma Glucose (FPG)

Blood glucose after ≥8 hours without caloric intake

Oral Glucose Tolerance Test (OGTT)

Measures blood glucose response to 75g oral glucose over 2 hours

Normal OGTT

Blood sugar rises and returns to baseline quickly

Prediabetes OGTT

Blood sugar rises higher and returns to baseline slowly

Diabetes OGTT

Blood sugar rises significantly and remains elevated

Healthy Blood Glucose Level

< 140 mg/dL (7.8 mmol/L)

Prediabetes Blood Glucose Level

140–199 mg/dL (7.8–11 mmol/L)

Diabetes Blood Glucose Level

≥200 mg/dL (11.1 mmol/L)

Glycosylated Hemoglobin (HbA1c)

Measures average blood glucose over past 3 months

Long-Term Complications Diabetes

Cardiovascular disease, neuropathy, nephropathy, retinopathy, skin and foot problems

Cardiovascular Disease in Diabetes

Heart attacks, stroke, hypertension, poor circulation due to high glucose damaging nerves and small vessels

Neuropathy

Numbness, tingling, pain in hands/feet, digestive issues caused by capillary and nerve damage

Nephropathy

Kidney damage leading to proteinuria, CKD, or ESRD due to hyperglycemia injuring glomeruli

Retinopathy

Vision loss, blindness, glaucoma, cataracts due to damaged retinal blood vessels from hyperglycemia

Skin and Foot Issues

Slow wound healing, infections, ulcers, risk of amputation due to impaired inflammation and tissue repair