It is recommended to improve lifestyle, diet, exercise, prevent prediabetes and reduce the risk of diabetes – a disease that is becoming a threat to the whole society.
1. What is prediabetes?
1.1 Prediabetes is a precursor group to diabetes
Type 2 diabetes onset when blood sugar levels gradually rise due to lifestyle factors such as overeating, lack of exercise, and obesity. During the development of diabetes, “prediabetes” lies between the normal body phase and the diabetic phase. The blood sugar level of prediabetic patients is higher than normal values. Although diabetes has not yet developed, if the patient continues to maintain such a lifestyle, there is a high chance of developing diabetes.
1.2 Prediabetes is potentially life-threatening
According to the “National Health and Nutrition Survey” conducted by the Japanese Ministry of Health, Labor and Social Welfare in 2009, there are about 10 million people in the precursor group of diabetes who have not been diagnosed with diabetes in Japan.
Patients should not have the reassuring thought that “Prediabetes is not diabetes so it’s okay.” Prediabetes doesn’t just have an increased risk of diabetes onset in healthy people. But the phenomenon of “arteriosclerosis” also begins to progress from the precursor stage of diabetes.
1.3 Life-threatening diseases caused by arteriosclerosis
Arteriosclerosis is a state in which fat called fibrous plaque sticks to the walls of blood vessels and becomes thicker.
People with high blood sugar are more likely to develop fibrous plaques and gradually the blood vessels of the entire body are torn apart. Progressive arteriosclerosis will increase the risk of causing diseases caused by arteriosclerosis such as “angina”, “myocardial infarction”, “cerebral infarction” and “obstructive arteriosclerosis”. Since arteriosclerosis progresses slowly over time, it is important for patients to pay attention to prevent the onset and progression of the disease.
2. Diagnostic criteria for prediabetes
2. Diagnostic criteria for prediabetes
The fasting glycemic index, as its name suggests, is a test to measure the glycemic index after taking a blood sample of a patient in a starving state.
Patients must abstain from breakfast on the day of the test and water intake is limited to water and tea that does not contain sugar. This test is an item that takes a blood sample during a general physical exam.
The Japan Diabetes Association’s 2016 treatment guidelines classified people with a fasting glycemic index of “110~126 mg/dL” as prediabetes. However, people with readings of “100~109 mg/dL” are classified as “normal high values” and are distinguished from “normal values” because prediabetes can be detected by an oral glucose tolerance test (OGTT).
An oral glucose tolerance test (OGTT) may be performed when the fasting glycemic index is classified as “prediabetes” and “normal high values.”
Fasting glycemic index criteria of prediabetes:
| Classify | Fasting glycemic index |
| Diabetes | ≥ 126mg/dL |
| Prediabetes | 110~126mg/dL |
| Normal high values | 100~109mg/dL |
| Normal values | ≤ 100mg/dL |
2.2 Oral glucose tolerance test (OGTT)
An oral glucose tolerance test (OGTT) is a test method that is not performed during a general physical examination. This test is done when the patient fasts for more than 10 hours after dinner the previous day and takes a fasting blood sample. After that, the patient is absorbed with water-soluble glucose, blood samples are taken several times at certain intervals, then checked to see if there is an increase in blood sugar after meals and then blood sugar levels drop to normal values. In this test, it is possible to detect the “underlying diabetes” of subjects whose blood sugar levels only rise after eating even though normal blood sugar levels are normal.
<Procedure for the Oral Glucose Tolerance Test (OGTT)>
Patients need to fast for more than 10 hours after dinner the day before.
Take a hungry blood sample in the morning the next day (recommended around 9 a.m).
– Drink a 75g glucose solution dissolved in water.
Immediately after taking glucose, take a blood sample after 30 minutes, after 1 hour, after 2 hours.
The 2016 diabetes treatment guidelines specify that in the case of a 2-hour oral glucose tolerance test (OGTT) of 140~200 mg/dL, the patient is diagnosed with “prediabetes”. An oral glucose tolerance test is done only when your doctor deems it necessary. Therefore, patients who are concerned about hyperglycemia after meals, visit the “Department of Internal Medicine” or “Department of Internal Medicine for Diabetes” and consult a doctor.
Oral glucose tolerance index (OGTT) criteria for prediabetes:
| Classify | Index in 2 hours oral glucose tolerance test (OGTT) |
| Diabetes | ≥ 200mg/dL |
| Prediabetes | 140~200mg/dL |
| Normal values | < 140mg/dL |
Who needs an oral glucose tolerance test (OGTT)
An oral glucose tolerance test (OGTT) is a test that is not performed during a normal physical examination. In the diagnosis of diabetes, this test will be done as prescribed by your doctor only if necessary.
In the 2016 diabetes guidelines, patients with “fasting glycemic index of 110~125 mg/dL” and “HbA1c value of 6.0~6.4”, OGTT should be tested and even if the patient has “fasting glycemic index of 100~109 mg/dL”, “HbA1c value is 5.6~5.9”, in case the family has someone with diabetes or is obese themselves, the OGTT test is recommended.
<When should OGTT be tested>
| Strong recommendations | Should proceed | |
| Fasting glycemic index | 110~125mg/dL | 110~125mg/dL |
| HbA1c | 6.0~6.4 | 5.6~5.9 |
| Other factors | Random glycemic index 110~125 mg/dL | The family has someone with diabetes, himself is obese |
3. People with prediabetes should quickly improve their lifestyle
3.1 Lifestyle improvements can improve blood sugar levels
If the patient continues to maintain an unhealthy lifestyle such as overeating and lack of exercise with the mindset “Since I don’t have diabetes, I don’t need to care about anything now”, it will gradually progress to diabetes.
Diabetes has almost no symptoms, and is difficult to cure when it develops. However, in the case of prediabetes, patients can lower their blood sugar levels by paying attention to a healthy lifestyle.
3.2 Methods to improve blood sugar
In order not to get diabetes, it is important to pay attention about daily eating.
Although most people know that overeating will lead to an increase in blood sugar, there are also many people who don’t really know what diet is right for them.
To prevent overeating, patients first need to know their “right weight” and “amount of physical activity”.
– Appropriate weight
The right weight is calculated as “22×squared height (m)”.
For example, the standard weight of a person 170 cm tall is 1.7 m × 1.7 m × 22=63.58 kg.
– The amount of physical activity
The amount of physical activity will vary the amount of calories that can be consumed per day according to the content of the job.
| Light work (mostly office work) | 25〜30 kcal/kg |
| Casual work (most of the work usually has to stand) | 30〜35 kcal/kg |
| Heavy work (mostly manual labor work) | 35〜 40 kcal/kg |
– Appropriate calorie intake
Proper calorie intake is calculated as “the right weight × amount of physical activity.”
In case an office worker is 170cm tall, calories will be calculated as 30 kcal x 63.58 kg = 1907 kcal / day.
3.3 Methods to improve blood sugar (<>): movement
Exercise can reduce already elevated blood sugar, people with diabetes will apply treatment with “movement therapy”. Exercise is effective in preventing diabetes, and regular “aerobic exercise” and “endurance exercise” are recommended in the e-healthnet of the Japanese Ministry of Health, Labor and Social Welfare.
– Aerobic exercise
Try to do aerobic exercises such as “walking”, “jogging”, “cycling”, “swimming”,… at least 3-5 times a week. Aerobic exercise is said to be effective for hyperglycemia if you do exercise at a level that you feel “just right” for 20-60 minutes a day.
– Endurance training
In addition to aerobic exercise, if you do “endurance training” to train your muscles, you will be more effective in improving blood sugar levels. It is possible to do exercises such as “abs”, “squat”, “push-ups”, “weight exercises” along with aerobic exercise 2-3 times a week.
Other target values
Besides the glycemic index, weight and cholesterol management is also important. The following section introduces the general target values described in the “Diabetes Treatment Guidelines 2016 – 2017”.
| HbA1c | < 6.0 |
| Maintain a standard weight | Above less than 22 BMI (BMI is a numerical value indicating the degree of obesity, calculated as [weight (kg)] ÷ [height squared (m)] ) |
| Blood pressure | < 130/80 mmHg (blood pressure measured at home <125/75 mmHg) |
| LDL cholesterol | <120 mg/dL (<100 mg/dL in coronary artery disease) |
| HDI cholesterol | ≥40mg/dL |
| Triglycerides (when hungry in the early morning) | <150mg/dL |
| Non-HDL Cholesterol | <150 mg/dL (<130 mg/dL in coronary artery disease) |
4. Conclusions
Diabetes (type 2) is thought to be caused by chronic hyperglycemia. Prediabetes falls between the normal body phase and the diabetic stage, also known as the “diabetes precursor group.” At the stage of prediabetes, if the patient comprehensively improves his lifestyle, it is possible to lower blood sugar levels and prevent the onset of diabetes. Once diabetes develops, patients must continue treatment to lower blood sugar. The risk of developing typical complications of diabetes is significantly reduced, the quality of life will also increase. “Prevention” before diabetes develops is the most important thing to be able to maintain a healthy life.