Keeping your blood glucose close to normal will definitely make you less likely to get eye damage or heart disease in the future. But doing everything to keep your blood glucose close to normal is really hard work. Watching what you eat, checking your blood glucose a lot, making adjustments in your food, exercise, pills or insulin... the constant grind of paying attention to every little detail can wear you out. Some people can manage it for months or years on end, but others find that they can't keep it up all of the time. They worry that if their blood glucose levels drift up that they will have lost all the benefit of those years when they kept it close to normal. Some recent research studies give very encouraging results about this.
The biggest study looking at the effect of blood glucose control on long term complications for people with type 1 diabetes was the Diabetes Control and Complications Trial (DCCT). After six and a half years of the study the people who kept their blood glucose closer to normal had a lot less eye damage, kidney damage and nerve damage than those whose blood glucose levels were higher. At the end of the study the difference in blood glucose control between the two groups (those with "intensive management" and those with more regular treatment) was lost in a year or two. In other words those who had been managed intensively to keep their blood glucose control close to normal "slacked off" a little while those in the less intensive group tightened up their efforts a bit. So for the next several years all the people who had been in the DCCT had about the same level of control as each other. The surprising thing was that the group who HAD kept their blood glucose levels closer to normal for the six and a half years of the study continued to have lower rates of eye damage, heart disease and other problems. The benefits of their years of hard work continued even when they had "slacked off."
Just recently the same thing has been found for people with type 2 diabetes. The largest study to look at the effects of blood glucose levels on diabetic complications for people with type 2 diabetes was the United Kingdom Prospective Diabetes Study (UKPDS). That study showed that people who kept their blood glucose closer to normal had fewer problems with their eyes and blood vessels and heart. It has been over ten years since the UKPDS finished. Within a year the blood glucose levels for the people in that study had drifted closer together so that for the next eight to ten years they all had about the same level of blood glucose. But once again, those who HAD kept their blood glucose closer to normal during the study continued to have healthier eyes and hearts than those who had had higher blood glucose levels during the study.
I think the follow up results from the DCCT and the UKPDS are very encouraging. What they tell us is that if you can keep your blood glucose levels close to normal for many months or years that the benefit you get from this lasts for a very long time. So if you drift for a while and can't keep things as close to normal as you used to don't beat up on yourself. There are times when your life circumstances change and it is harder to do everything right. Maybe you got divorced. Maybe you lost a job. Maybe you are looking after a family member who is ill and it takes up all of your time. If your average blood glucose levels are not as good now as they used to be don't be discouraged. Your body is still getting the benefit from all those years when you kept your blood glucose levels close to normal. And if you can get back on track and bring your average back down again you will get even more benefit.
