To explain what hemoglobin A1c is, think in simple terms. Sugar sticks, and when it's around for a long time, it's harder to get it off. In the body, sugar sticks too, particularly to proteins. The red blood cells that circulate in the body live for about three months before they die off. When sugar sticks to these hemoglobin proteins in these cells, it is known as glycosylated hemoglobin or hemoglobin A1c (HBA1c). Measurement of HBA1c gives us an idea of how much sugar is present in the bloodstream for the preceding three months. In most labs, the normal range is 4%-5.9 %. In poorly controlled diabetes, its 8.0% or above, and in well controlled patients it's less than 7.0% (optimal is <6.5%). The benefits of measuring A1c is that is gives a more reasonable and stable view of what's happening over the course of time (three months), and the value does not vary as much as finger stick blood sugar measurements. There is a direct correlation between A1c levels and average blood sugar levels as follows.
Diabetes mellitus is a chronic disease, for which there is no known cure except in very specific situations. Management concentrates on keeping blood sugar levels as close to normal, without causing low blood sugar. This can usually be accomplished with a healthy diet, exercise, weight loss, and use of appropriate medications (insulin in the case of type 1 diabetes; oral medications, as well as possibly insulin, in type 2 diabetes).[medical citation needed]
In 2013, of the estimated 382 million people with diabetes globally, more than 80 per cent lived in LMIC. It was estimated that India had 65.1 million adults with diabetes in 2013, and had the 2nd position among the top 10 countries with the largest number of diabetes. This number is predicted to increase to 109 million by 2035 unless steps are taken to prevent new cases of diabetes1. Primary prevention of diabetes is feasible and strategies such as lifestyle modification are shown to be effective in populations of varied ethnicity2,3. However, for implementation of the strategies at the population level, national programmes which are culturally and socially acceptable and practical have to be formulated which are currently lacking in most of the developed and developing countries. Early diagnosis and institution of appropriate therapeutic measures yield the desired glycaemic outcomes and prevent the vascular complications4.
Environmental factors are important, because even identical twins have only a 30-60% concordance for type 1 diabetes mellitus and because incidence rates vary in genetically similar populations under different living conditions.  No single factor has been identified, but infections and diet are considered the 2 most likely environmental candidates.
Although this complication is not seen in pediatric patients, it is a significant cause of morbidity and premature mortality in adults with diabetes. People with type 1 diabetes mellitus have twice the risk of fatal myocardial infarction (MI) and stroke that people unaffected with diabetes do; in women, the MI risk is 4 times greater. People with type 1 diabetes mellitus also have 4 times greater risk for atherosclerosis.
The genes identified so far in people with type 2 include many that affect the insulin-producing beta cells of the pancreas, says Craig Hanis, PhD, a professor at the Human Genetics Center at the University of Texas Health Science Center in Houston. And yet he emphasizes that why people get type 2 isn't at all clear yet: "What it tells us is that diabetes is a complicated disease."
Glucose is a simple sugar found in food. Glucose is an essential nutrient that provides energy for the proper functioning of the body cells. Carbohydrates are broken down in the small intestine and the glucose in digested food is then absorbed by the intestinal cells into the bloodstream, and is carried by the bloodstream to all the cells in the body where it is utilized. However, glucose cannot enter the cells alone and needs insulin to aid in its transport into the cells. Without insulin, the cells become starved of glucose energy despite the presence of abundant glucose in the bloodstream. In certain types of diabetes, the cells' inability to utilize glucose gives rise to the ironic situation of "starvation in the midst of plenty". The abundant, unutilized glucose is wastefully excreted in the urine.
Onset of type 2 diabetes can be delayed or prevented through proper nutrition and regular exercise. Intensive lifestyle measures may reduce the risk by over half. The benefit of exercise occurs regardless of the person's initial weight or subsequent weight loss. High levels of physical activity reduce the risk of diabetes by about 28%. Evidence for the benefit of dietary changes alone, however, is limited, with some evidence for a diet high in green leafy vegetables and some for limiting the intake of sugary drinks. In those with impaired glucose tolerance, diet and exercise either alone or in combination with metformin or acarbose may decrease the risk of developing diabetes. Lifestyle interventions are more effective than metformin. A 2017 review found that, long term, lifestyle changes decreased the risk by 28%, while medication does not reduce risk after withdrawal. While low vitamin D levels are associated with an increased risk of diabetes, correcting the levels by supplementing vitamin D3 does not improve that risk.
Type 2 diabetes, which is often diagnosed when a person has an A1C of at least 7 on two separate occasions, can lead to potentially serious issues, like neuropathy, or nerve damage; vision problems; an increased risk of heart disease; and other diabetes complications. A person’s A1C is the two- to three-month average of his or her blood sugar levels.