It now appears that type 2 diabetes is largely preventable.
In type 2 diabetes, the body still produces insulin, but the body's cells become resistant to it -- a condition called insulin resistance. As a result of this insulin resistance, blood glucose levels become elevated, and several other metabolic problems occur that, taken together, often lead to heart disease, stroke, kidney disease, blindness, neuropathy, and peripheral vascular disease. In fact, up to 70% of patients with type 2 diabetes die from heart or vascular problems.
In recent years, the incidence of type 2 diabetes has been climbing, and while formerly a disease of middle-aged and older people, now it is being seen in younger and younger patients every year. Most doctors have speculated that the increased incidence of type 2 diabetes, and the alarming change in the age-distribution of this condition, is related to the fact that our population is getting fatter.
And if that's true -- if type 2 diabetes is increasing because of certain behaviors and habits that people adopt, such as allowing themselves to become obese -- then that means the diabetes should be preventable.
As it turns out, the idea that type 2 diabetes is preventable, in at least most cases, is much more than mere speculation. There's enough good clinical evidence today to make a conclusive statement about this. That evidence takes at least three forms:
1. The increasing incidence of type 2 diabetes, and its changing age distribution, has tracked almost exactly with the increasing incidence (and age distribution) of obesity in our culture. As our population becomes more obese, and as obesity is seen at younger and younger ages, the increase in type 2 diabetes has run a parallel course. Furthermore (and most importantly), the type 2 diabetes occurs almost exclusively in the individuals who are, in fact, overweight.
2. The related condition of metabolic syndrome (now often called pre-diabetes, because it often precedes type 2 diabetes) is clearly produced by obesity and a sedentary lifestyle. Furthermore, metabolic syndrome is now known to be reversible in many people who lose weight, eat right, and exercise.
3. At least two large observational studies have now concluded that type 2 diabetes is preventable with appropriate lifestyle choices:
- In a population of 85,000 female nurses followed for 16 years, the 3,300 nurses who developed type 2 diabetes were significantly more obese, more sedentary, ate poorer diets, and were more likely to smoke than the nurses who did not develop diabetes. The investigators estimated that nearly 90% of the type 2 diabetes in this population was related to lifestyle choices.
- In the National Institutes of Health--AARP Diet and Health Study, a population of nearly 115,000 men and 92,000 women were followed for 10 years, and about 10% of the men and 8% of the women developed type 2 diabetes. Type 2 diabetes was strongly associated with those same risk factors (weight, diet, activity and smoking). Taken together, 80% of the diabetes appearing in these patients could be accounted for by one or more of these risk factors. However, being overweight produced the highest risk, and the investigators estimated that having a normal weight, by itself, reduced the risk of developing type 2 diabetes by 60 or 70%.
The bottom line is this: Type 2 diabetes is a very serious condition that often takes a decade or more away from your life -- and the years that you do have are often much more miserable than they ought to be. So if you can prevent type 2 diabetes, you should try.
Type 2 diabetes occurs in susceptible people who gain too much weight, who are sedentary, who have poor diets, and/or who smoke. How do you know if you are susceptible? You may not -- but if you have family members with type 2 diabetes or metabolic syndrome, odds are that you're susceptible, too.
But susceptible or not, the lifestyle choices we're talking about here are healthy for anyone, and will reduce your risk of cardiovascular disease even if you're not prone to diabetes. So taking the steps to prevent type 2 diabetes is a wise decision all around.
Hu FB, Manson JE, Stampfer MJ, et al. Diet, Lifestyle, and the Risk of Type 2 Diabetes Mellitus in Women. N Engl J Med 2001; September 13, 2001 345:790-797.
Reis JP, Loria CM, Sorlie PD, et al. Lifestyle Factors and Risk for New-Onset Diabetes - A Population-Based Cohort Study. Ann Intern Med September 6, 2011 155:I-30.