Diabetes: Types, Causes, Symptoms, and Treatment
Also known as: Diabetes Mellitus, Type 1 Diabetes, Type 2 Diabetes, Gestational Diabetes, High Blood Sugar
What is diabetes?
Diabetes is a chronic condition marked by too much sugar (glucose) in the blood, known as hyperglycemia. In the United States, more than 38 million people have diabetes, and 90% to 95% of those cases are type 2. There are two main forms: type 1 diabetes, an autoimmune condition that mostly appears in children and young adults, and type 2 diabetes, linked to insulin resistance and strongly tied to lifestyle. There is also gestational diabetes, which develops during pregnancy and usually resolves after birth.
Causes and risk factors
Causes differ by type of diabetes. Type 1 diabetes results from an autoimmune process that destroys the insulin-producing cells in the pancreas, and it is unrelated to lifestyle. Type 2 diabetes is driven by excess weight, a sedentary lifestyle, an unbalanced diet, age 35 or older, and family history. Gestational diabetes occurs during pregnancy because the body cannot make the extra insulin it needs, with higher risk among women who are overweight or have a family history of diabetes.
Symptoms
Classic symptoms include intense thirst, heavy urination, unusual fatigue, weight loss (especially with type 1), blurred vision, and slow-healing wounds. Type 2 diabetes can remain symptom-free for a long time, and is often found incidentally during a routine blood test, while type 1 diabetes usually appears more suddenly in children or young adults.
Diagnosis
Diagnosis relies on measuring fasting blood glucose, with a value of 126 mg/dL or higher indicating diabetes, usually confirmed with a second test. Hemoglobin A1c (HbA1c), which reflects blood sugar control over the past three months, is also used for diagnosis and monitoring, with a result of 6.5% or above indicating diabetes. For gestational diabetes, an oral glucose tolerance test is done between weeks 24 and 28 of pregnancy. Additional tests assess for any related complications.
Available treatments
Management varies by type of diabetes:
- Type 1 diabetes: insulin therapy is required, delivered by injection, pen, or an insulin pump
- Type 2 diabetes: lifestyle measures first, then oral diabetes medication (most people start with metformin), and insulin if needed
- Gestational diabetes: dietary changes, blood sugar self-monitoring, and insulin if diet and activity are not enough
- Regular blood sugar self-monitoring to adjust treatment day to day
- Complication monitoring: a dilated eye exam and kidney blood and urine tests once a year, a thorough exam of the feeling in your feet and legs at least once a year, a foot check at every visit with your care team, blood pressure at every visit, and a cholesterol test once a year for most adults with type 2 diabetes
Multidisciplinary follow-up with a primary care doctor, an endocrinologist, and a dietitian is essential to optimize blood sugar control.
Prevention and practical tips
Type 2 diabetes can often be prevented or delayed through a balanced diet, regular physical activity (at least 30 minutes a day, 5 days a week, or about 150 minutes a week), and reaching a healthy weight. Losing 5% to 7% of your starting weight measurably lowers your risk. Limit refined sugar and saturated fat, favor fiber-rich foods, and drink water instead of sweetened beverages. Regular blood sugar screening is recommended starting at age 35, or earlier if you have risk factors such as excess weight, family history, or a sedentary lifestyle.
When should you see a doctor?
See a doctor for intense thirst, frequent urination, unusual fatigue, or unexplained weight loss. Regular screening is recommended if you have risk factors, even without symptoms.
Sources
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), official U.S. government guidance on diabetes
- CDC: Diabetes Basics, type 2 accounts for about 90% to 95% of all diagnosed diabetes cases
- NIDDK, Diabetes Statistics, U.S. prevalence data
- NIDDK, Symptoms & Causes of Diabetes, symptoms, type 2 risk factors including age 35 or older, and gestational diabetes cause
- NIDDK, Diabetes Tests & Diagnosis, fasting glucose and A1C thresholds and gestational testing at weeks 24 to 28
- NIDDK, Preventing Type 2 Diabetes, diet, activity, and weight guidance
- NIDDK, Insulin, Medicines, and Other Diabetes Treatments, treatment options by type
- NIDDK, Preventing Diabetes Problems, yearly dilated eye exam and a foot check at every visit
- NIDDK, Diabetic Kidney Disease, yearly blood and urine tests for kidney disease
- NIDDK, Peripheral Neuropathy, yearly exam of feeling in the feet and legs
- MedlinePlus, Diabetes tests and checkups, monitoring schedule for eyes, kidneys, feet, blood pressure, and cholesterol
- MedlinePlus, U.S. National Library of Medicine health information
- U.S. Preventive Services Task Force, screening recommendations for prediabetes and type 2 diabetes