An estimated 21 million Americans (7 percent) have been diagnosed with diabetes and another 6 million have the disease but haven't been diagnosed, according to the Centers for Disease Control and Prevention (CDC). Another 4 million Americans have "pre-diabetes," which increases the risk of developing Type 2 diabetes. Two-thirds of people with diabetes die of a heart attack or stroke. While diabetes can cause serious health problems, you can reduce difficulties when applying for life insurance.

The key to buying affordable life insurance if you have diabetes is one word: control. If you are controlling your diabetes by visiting your doctor regularly, taking your medications, and responding well to your treatments, you may still be able to find a variety of life insurance policies available to you.

Insurers look primarily at your blood-sugar levels and your hemoglobin A1C count to determine how well you are responding to your treatment over time. Your best strategy is to show a history of effective treatment, including yearly eye exams, and that your other risk factors — such as weight and blood pressure — are in normal ranges.

Ratings classes

• Super Preferred (sometimes called Preferred Plus)
• Preferred
• Standard
• Substandard

Those with juvenile-onset diabetes, called Type 1 diabetes, will likely have a tough time finding traditional, medically underwritten life insurance. A person who has had diabetes for some time already — someone diagnosed five, 10, or 15 years ago with juvenile-onset diabetes — is much more likely to suffer "end organ" diseases brought on by diabetes early in life. This makes life insurance more expensive.

In the best scenarios, Type 1 diabetics may be quoted premium prices in a "high substandard" rating class, no matter what their level of control of the disease — and that's going to be expensive. If you have Type 1 diabetes, you could also try finding a "simplified issue" policy that is not medically underwritten. You will still face high premiums but it may be your best bet to secure life insurance.

Adult-onset diabetes, known as Type 2 diabetes, which according to the CDC represents 90 to 95 percent of all diagnosed cases, can be treated by adjustments to your diet and exercise, oral medications, or insulin therapy, but insurers tend to be less concerned with how you are treating your diabetes than with how you are responding to your treatments.

If you can show your Type 2 diabetes is under control, you will likely fall in a "standard" rating class for life insurance pricing, or even slightly better with some life insurers who are more aggressive in writing policies for diabetics. Many life insurers have a rating class that falls between Standard and Preferred, called Standard Plus, which is where the ideal Type 2 diabetic applicant might end up.

"Most people with adult-onset diabetes are insurable at some rate," says Christopher Graham, vice president and chief underwriter for Hartford Life. "And many diabetics get 'standard' products."

The age of onset of Type 2 diabetes is also important. If you developed the condition early in life, such as teens or 20s, you will likely be charged higher life insurance rates than someone who developed it later.

"As an insurer, you only get one shot at pricing a life insurance policy," says Graham. "If there are unknowns, you tend to hedge your bets."

Six months may be enough of a history for a newly diagnosed case of diabetes, or for someone who has changed to a different style of treatment, to show he is responding better. But if you have had poor control in the past you will have to establish a longer history of good control — perhaps as much as a year — to get a better price for your life insurance policy.

The savings you can realize by improving your control of the disease can be substantial.