What are the differences between diabetes Type 1 and Type 2, and why do they matter? Only after my son Casey was diagnosed with Type 1 did I understand why I had difficulty distinguishing the two types, despite having an uncle with Type 2 and a close family friend with Type 1. The two types are similar but differ in fundamental ways.
In 2022 the Center for Disease Control and Prevention (CDC) reported that 14.7 percent of American adults have diabetes (37.1 million) and another 38 percent (96 million) have prediabetes, putting them at high risk for developing it. Type 2 accounts for 90-95 percent of diabetes cases and Type 1 only 5 percent. Diabetes is epidemic in rich countries, where overweight and obesity have become the norm. It has spread down the global income ladder in the last half century as urbanization and economic development transformed lifestyles in even the poorest countries. Although cases of Type 1 have increased since 2001, the epidemic is of Type 2.
Types 1 and 2 are both “derangements in carbohydrate metabolism” characterized by persistently too-high blood glucose (BG) which, if left uncontrolled, does body-wide damage. However, their causes, progression and implications for daily life differ markedly.
Type 1 tends to develop early in life, come to attention abruptly as visible symptoms coalesce, and cannot (yet) be prevented. Type 2 tends to develop in middle to late adulthood, can progress unnoticed for decades, and is virtually always preventable. The derangement of carbohydrate metabolism in Type 1 is precipitated when the body begins destroying the pancreatic (beta) cells that produce insulin. As the autoimmune attack proceeds, the pancreas produces less insulin, so more glucose circulates unused. Once the months-long to years-long attack has destroyed 80 percent of the beta cells, the body can no longer produce the insulin needed to deliver glucose to waiting cells, depriving them of their chief source of energy. The presence of Type 1 screams loudly when BG rises to dangerous levels, necessitating emergency medical care. Insulin injections are required multiple times a day for life.
Type 2 begins with damage, not to insulin producing cells, but to the cells awaiting glucose deliveries: they increasingly resist the efforts of insulin to deliver glucose, so they receive less from the same amount of insulin and unused glucose accumulates in the blood stream. The gradual rise in BG levels over time produces no obvious symptoms, so Type 2 can progress unnoticed for years, until lab tests reveal signs of internal damage, such as elevated cholesterol and blood lipids.
Genetic differences make some people more susceptible than others to the risk factors for diabetes, but those risks differ for Types 1 and 2. Viral infections and various environmental factors are thought to trigger or increase the severity of the autoimmune attack in Type 1. Hearing Casey’s Type 1 diagnosis, we wrongly thought we allowed him too many sugary desserts. The risk factors for Type 2 are behavioral: unhealthy diet, being sedentary, smoking and drinking alcohol to excess.
Both types of diabetes run in families, but not in ways I expected. I had assumed Casey wasn’t at risk for Type 1 because none of my biological relatives have it, so was surprised to learn that 93 percent of people with Type 1 have no family history of it. While the lifetime risk of developing Type 1 is 1 percent in the general American population, it is 10 percent to 20 percent when a first-degree relative has it. People with Type 2 often have family members with Type 2, but that may result more from shared lifestyle than shared genes.
Differences in the nature of Types 1 and 2 mean that their day-to-day demands differ too. All people with diabetes should monitor their carbohydrate intake and BG levels. But everyone with Type 1 must, as must the one in four people with Type 2 who use insulin to bring down high BG. Insulin users must do what their bodies no longer can—calculate how much insulin to inject to cover the amount of carbohydrate in each meal. Many foods lack nutrition labels, so estimating a meal’s carbohydrate content is challenging. Underestimating it (and therefore taking too little insulin) results in temporary hyperglycemia. But overestimating (and taking too much insulin) is hazardous. It can plunge someone into severe hypoglycemia and potentially a coma, which is especially dangerous during sleep. Using insulin helps keep BG from going too high, but it’s a constant challenge to keep it from dropping dangerously low, especially for active individuals.
Misconceptions about diabetes center on carbohydrate, which comes in many forms, simple and complex: sugar, starch and fiber. The body turns them all, except fiber, into glucose. Referring to BG as blood sugar led to the term sugar diabetes, leading many people to mistakenly assume that only sugar raises BG, consuming sugary foods is thus the cause of diabetes, and not eating them is necessary to control BG. This narrow focus on sugar also fosters the misconception that only pastries, candy and other sweets contain sugar, but many manufactured foods do too, including most salad dressings, cereal and convenience foods. Fruits, dairy products and some vegetables contain naturally occurring sugars. Foods such as pasta and rice contain complex carbohydrates. Eating an all-protein diet to control BG isn’t a good idea; the challenge is to identify carbohydrates and select them wisely.
Both Type 1 and Type 2 require a lifetime of conscientious self-management to avoid the complications of poorly controlled BG, including heart and kidney disease, vision loss, nerve damage and limb amputation. Healthful eating is crucial. No food is forbidden, although some make it harder to control BG. Physical activity is likewise crucial to controlling BG but, being unquantifiable, makes adjusting medication and carbohydrate intake even harder. Both types of diabetes are complex, 24-7 jobs, but Type 1 is far more demanding. Even so, people with diabetes can live long, healthy lives if their BG levels are well managed. Diabetes need not limit their life goals.
Lisa Seitles
Hammonton
Lisa Seitles and her husband Sam are the owners of READ Preschool and Camp Tuscaloosa. They have four children and are active members of the community.