By Mai Martinez

(CBS) — Every year, another 1.5 million people are diagnosed with diabetes.

Lifestyle changes and medication can help control the disease and prolong lives, but a new study finds many people delay treatment.

“It’s a secret killer. It’s scary.”

And that’s why Mark Pence was floored when he found out he had diabetes three years ago, after his brother-in-law — who’s diabetic — jokingly asked to check his blood sugar.

“It was like out of the ballpark. I had no symptoms. I felt fine. Then I went to my doctor and he said yes, you are a Type Two diabetic,” Pence says.

He adds: “It was a pretty big shock because I exercise a lot. I eat fairly well. I’m not a sugar freak or anything like that.”

It’s a big shock for many patients, according to Northwestern’s Dr. Amisha Wallia.

That, combined with misconceptions about diabetes and fear of needles and injections, can prompt some patients to delay treatment.

A recent study found three in 10 adults with Type 2 diabetes put off insulin treatments, for about two years.

“That two-year delay can be very significant, so high blood sugars in the immediate period can cause increase in infection, can acutely cause blurry vision, and long-term can worsen kidney disease as well as eye disease,” Wallia says.

Dr. Wallia adds it’s hard to reverse course once the complications occur.

“Prevention is always the key.”

That’s exactly what Pence did, and through changes in his lifestyle and eating habits, he lost 15 pounds. As of this summer, he lowered his blood sugar enough to be considered pre-diabetic.

“I’ve got to keep vigilant,” Pence says.

Both Pence and Dr. Wallia say awareness is key to fighting diabetes, and that’s why they’ll join CBS 2 and hundreds of others for the Step Out Walk to Stop Diabetes Walk Saturday morning.