What is Diabetes Mellitus?
Ever heard someone say, “I have sugar”? They’re likely talking about diabetes mellitus—a long-term condition where the body struggles to manage blood sugar levels properly.
In simple terms, diabetes happens when your body can’t make enough insulin or can’t use it effectively. Insulin is like a key that helps sugar (glucose) enter your cells to be used as energy. Without it, sugar builds up in your blood.
Globally, more than 500 million people are living with diabetes, and the number keeps rising. According to the International Diabetes Federation (IDF), 1 in 10 adults had diabetes in 2021, and half of them didn’t even know it yet! It’s a quiet condition, often creeping in unnoticed until complications hit.
How Does It Occur?
Think of your body as a car. Glucose is the fuel, and insulin is the key that starts the engine so the fuel can be used. In diabetes:
- Either the key (insulin) is missing – like in Type 1 Diabetes, or
- The lock is jammed – the body resists insulin – like in Type 2 Diabetes.
Over time, sugar keeps piling up in your bloodstream. High blood sugar slowly damages blood vessels, nerves, kidneys, eyes, and even your heart.
In Type 1 diabetes, the immune system wrongly attacks the pancreas, stopping insulin production. In Type 2, the body still makes insulin, but the cells ignore it, demanding more and more over time until the pancreas gets worn out.
What are the Causes of Diabetes Mellitus?
The causes vary depending on the type, but here’s a breakdown:
- Type 1 Diabetes: This is an autoimmune condition. The exact cause isn’t fully understood, but it’s believed to involve genetic factors and possible viral triggers. It usually starts in childhood or adolescence. Around 5–10% of all diabetes cases are Type 1.
- Type 2 Diabetes: This is mainly linked to lifestyle and genetics. It accounts for 90–95% of diabetes cases. The body becomes resistant to insulin, often due to:
- Being overweight
- Lack of physical activity
- Poor diet
- Family history of diabetes
- Gestational Diabetes: This occurs during pregnancy and is due to hormonal changes that make the body more insulin resistant.
Other rare causes include:
- Genetic mutations (MODY, neonatal diabetes)
- Pancreatic diseases
- Long-term use of certain medications (e.g., steroids)
Risk Factors
Not everyone is at equal risk. Some people have a higher chance of developing diabetes, especially Type 2. But what makes one person more likely than another?
Here’s what puts you in the danger zone:
- Age over 45
- Family history of diabetes
- Being overweight or obese (especially with belly fat)
- Sedentary lifestyle
- Unhealthy diet (high in sugar and refined carbs)
- High blood pressure
- High cholesterol or triglycerides
- Polycystic ovarian syndrome (PCOS) in women
- Gestational diabetes history
- Belonging to certain ethnicities (e.g., South Asians, African Americans, Hispanics)
Among all, obesity and physical inactivity are the biggest red flags.
Symptoms of Diabetes Mellitus
Sometimes the signs are obvious. Other times, they’re so subtle you might think you’re just tired. But ignoring them can lead to serious problems.
Here’s what to watch for:
- Frequent urination: Excess sugar pulls water from the body.
- Excessive thirst: Due to dehydration from peeing a lot.
- Unexplained weight loss: Your body starts burning fat and muscle for fuel.
- Extreme fatigue: Cells are starving for energy.
- Blurred vision: High sugar affects the eye’s lens.
- Slow healing wounds: Sugar damages blood flow and immune function.
- Tingling or numbness in hands and feet: Due to nerve damage (neuropathy)
Don’t brush off these symptoms thinking they’ll go away. They won’t—not without help.
Differential Diagnosis
Let’s say someone comes in tired, losing weight, and drinking a lot of water. It could be diabetes, yes—but it could also be something else.
Some conditions that mimic diabetes symptoms include:
- Diabetes insipidus: A different condition altogether. Causes frequent urination and thirst, but not related to blood sugar.
- Hyperthyroidism: Speeds up metabolism, causing weight loss and fatigue.
- Chronic kidney disease: Can also cause fatigue and changes in urination.
- Cushing’s syndrome: May present with weight gain, high blood sugar, and fatigue.
That’s why proper testing is essential—guesswork doesn’t cut it.
How to Diagnose Diabetes Mellitus?
So how do doctors know for sure? It’s all in the bloodwork.
🏆 Gold Standard Tests:
- Fasting Blood Glucose Test
- After 8 hours of no food.
- Diabetes is confirmed if ≥126 mg/dL (7.0 mmol/L).
- HbA1c Test
- Measures average blood sugar over 2–3 months.
- Diabetes: ≥6.5%
- Oral Glucose Tolerance Test (OGTT)
- Drink a glucose solution, then check blood sugar after 2 hours.
- Diabetes: ≥200 mg/dL (11.1 mmol/L)
- Random Blood Sugar
- If ≥200 mg/dL with symptoms, that’s diabetes too.
These tests help distinguish between prediabetes, diabetes, or normal glucose levels.
Treatment of Diabetes Mellitus
Treatment isn’t one-size-fits-all. It depends on the type, severity, age, and overall health. But the goal is always the same: control blood sugar and prevent complications.
💊 For Type 1 Diabetes:
- Insulin is a must (because the body doesn’t make any).
- Types include rapid-acting, long-acting, and intermediate.
- Common brands: Humalog, Novolog, Lantus, Levemir
- Continuous glucose monitoring (CGM) and insulin pumps are often used for better control.
💊 For Type 2 Diabetes:
- First step? Lifestyle changes.
- Balanced diet (low sugar, high fibre)
- Regular exercise (30 mins/day)
- Weight loss (even 5–10% can help)
- If lifestyle isn’t enough, medications come next:
- Metformin (first-line drug)
- Others include:
- Sulfonylureas (e.g., glipizide)
- DPP-4 inhibitors (e.g., sitagliptin)
- SGLT2 inhibitors (e.g., empagliflozin)
- GLP-1 receptor agonists (e.g., semaglutide)
- Some patients may eventually need insulin too.
🤰 For Gestational Diabetes:
- Diet and exercise first
- If needed, insulin is preferred over tablets for safety during pregnancy
References
- International Diabetes Federation. IDF Diabetes Atlas 10th Edition (2021). https://diabetesatlas.org/
- American Diabetes Association. Diagnosis and Classification of Diabetes Mellitus. https://diabetesjournals.org/care/article/37/Supplement_1/S81/29302
- Mayo Clinic – Diabetes Overview. https://www.mayoclinic.org/diseases-conditions/diabetes/symptoms-causes/syc-20371444
- CDC – Managing Diabetes. https://www.cdc.gov/diabetes/basics/index.html
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). https://www.niddk.nih.gov/health-information/diabetes