Prediabetes - Frequently Asked Questions

1.    What is prediabetes?

Prediabetes is a state of hyperglycaemia where your blood sugar levels are higher than normal, but not high enough to be clinically classified as diabetes. Although not all people with prediabetes will develop diabetes, 70% of them will acquire diabetes in their lifetime(1).

2.    How do I know I have prediabetes?

Prediabetes often goes unnoticed without any obvious symptoms until diabetes develops. In New Zealand, HbA1c is the recommended diagnostic screening test for diabetes and pre-diabetes. An HbA1c test measures the concentration of glycated haemoglobin, or sugar attached to blood cells. This test indicates blood glucose levels over a period of up to 120 days.

3.    Who is at high risk of having prediabetes?

Individuals with an HbA1c of 41-49 mmol/mol and a fasting glucose concentration of 6.1-6.9 mmol/L are considered prediabetic.
The following groups of people are likely to be at high risk for type 2 diabetes:
•    Those with heart disease
•    Those on long term steroid or anti-psychotic treatment
•    Obese people (BMI ≥ 30 kg/m2 or ≥ 27 kg/m2 for Indo-Asian people)
•    People with a family history of early age onset of Type 2 diabetes in more than one direct relative
•    Women with a past personal history of gestational diabetes
•    Obese children and young adults (BMI ≥ 30 kg/m2 or ≥27 kg/m2 in Indo-Asian) with a family history of early onset Type 2 diabetes, or if they are of Māori, Pacific or Indo-Asian ethnicity
•    Women with Polycystic Ovarian Syndrome (PCOS)

4.    What increases the risk of prediabetes?

Risk factors of prediabetes can include genetic predisposition, ethnicity, environmental exposures, behavioural aspects, dietary patterns, physical activity, and stress responses2. Other risk factors include obesity, hypertension, high cholesterol, insulin resistance and family history of diabetes(3-5).

5.    How many New Zealanders are at risk of prediabetes and diabetes?

7.0% of New Zealand adults have diabetes, and 18.6% have prediabetes. 8.3% of diabetics in New Zealand are men, compared to 5.8% women. Diabetes is more common in obese people (14.2%) compared with the normal weight group (2.4%). The risk also increases with age(6).

6.    What are the dangers of prediabetes?

Diabetes is the leading cause of blindness, kidney failure and amputations. Diabetes can also cause complications including retinopathy(7) and cardiovascular diseases such as stroke8 and heart disease(4,7). There is a significant increase in cardiovascular diseases and mortality in prediabetic people compared with people with normal glucose tolerance(9).

7.    Does ethnicity play a part in my chances of getting diabetes?

There may be a difference between nationalities and ethnicities and their risk of developing prediabetes.

8.    What is the link between prediabetes and insulin resistance?

When you eat, sugar level in your blood rises. This triggers your pancreas to produce insulin, which stops sugar production in the liver, and allows the body to use sugar in the blood for energy. This process helps your body to maintain a healthy level of sugar in your blood. People who have diabetes or prediabetes become insulin resistant, where their bodies no longer respond to insulin and high amounts of sugar circulate in the bloodstream(10). Insulin resistance is likely to be caused by obesity, when excess fats damage key organs such as the pancreas and liver, which are responsible for blood sugar regulation(11). As insulin resistance progresses, insulin sensitivity and secretion may become impaired, and this often brings about prediabetes(12).

9.    If I am not overweight or obese, am I free from getting diabetes?

There are many causes of diabetes, and being overweight or obese is only one of these. You do not need to be overweight to be diagnosed with diabetes, but obesity has been strongly linked with developing diabetes(11).

10.    Is diabetes caused by the over-consumption of sugar?

Don’t put the blame on sugar! Although dietary carbohydrates increase blood sugar levels, carbohydrates are an important source of energy and nutrients, and avoiding them will not bring blood sugar levels down to healthy range(13). A number of risk factors such as abdominal obesity, high blood pressure, high triglycerides, reduced levels of high protein density lipoprotein (HDL or 'good') cholesterol, and physical inactivity are the main players in the development of insulin resistance and hyperglycaemia, making the individual predisposed to diabetes(5).

11.    Should I reduce on my sugar consumption if I am prediabetic?

Your blood sugar levels are directly influenced by the intake of carbohydrates. The types of carbohydrates (starchy foods and sugar) in a meal will have an effect on your blood sugar response. Therefore, controlling the consumption of sugary foods may help with your condition if you already have prediabetes(14). Having said that, if eaten as part of a healthy and well-balanced meal plan, or combined with exercise, you may still consume sweets and desserts, as long as you consume everything in moderation!

12.    Will consuming commercial supplements help with preventing diabetes?

As diabetes may be a state of increased oxidative stress, there has been a growing interest in antioxidant therapy(14). However results have been inconclusive as to whether foods high in antioxidants will help improve the diabetic condition(14). There is also inconclusive data regarding herbal supplements for diabetes treatment(15). In the GLARE study, our aim is to better understand how natural antioxidant-rich food extracts (grape seed-, rooibos tea-, and olive leaf extract) could help with reducing blood sugar levels in prediabetic people. Previous research has demonstrated that such extracts were able to modulate post-meal blood sugar levels in healthy individuals16. Other research has provided evidence that olive leaf extracts improved insulin sensitivity(17). These findings suggest there is potential for these food extracts to help with prediabetes in the future. Preventing progression to diabetes is key in this research!

13.    Can prediabetes be reversed?

The goal for people with prediabetes is to achieve normal blood sugar levels. The earlier prediabetes is treated, the easier it is for the individual to restore normal regulation of blood sugar(18). Early detection and intervention will help to reduce the risks of developing complications that are often associated with prediabetes and diabetes(2,18,19).

14.    If I have symptoms of prediabetes, is it too late to prevent diabetes?

Changing your lifestyle can play a big part in delaying the onset of diabetes. Exercise can help to slow the progression of prediabetes into diabetes20. Sometimes, medication may be prescribed although lifestyle changes have no side effects and may be more effective, having been shown to delay diabetes onset by up to 4 years(21-23). Maintaining a healthy weight and Body Mass Index (BMI), reducing total intake of fat and saturated fat, salt, and increasing the intake of fruits and vegetables, whole grains, lean meat, and unsaturated fats may also help in reducing diabetes risks(2,14,24).

15.    How long do I have to make the necessary lifestyle changes to reduce risks of diabetes?

It is important to maintain healthy normal blood sugar levels to minimise or delay the onset of symptoms(18). Therefore, it is always best to follow a healthy, balanced diet and get regular physical activity. Reducing 1 kilogram of weight could mean you reduce your diabetes risk by 16%(25). Furthermore, 150 minutes of moderate intensity physical exercise per week is recommended for people with prediabetes1. Reversing prediabetes requires a change in mindset and behaviour to stay healthy.

Before you go, do visit the to check out hot topics about prediabetes and diabetes and how you can better manage your prediabetic condition. You may also download the information about prediabetes through the following link:

Here are the useful references if you want to expand your reading on prediabetes:

1.         Tabak AG, Herder C, Rathmann W, Brunner EJ, Kivimaki M. Prediabetes: a high-risk state for diabetes development. Lancet. 2012;379(9833):2279-2290.
2.         Perreault L, Kahn SE, Christophi CA, Knowler WC, Hamman RF, Diabet Prevention Program Res G. Regression From Pre-Diabetes to Normal Glucose Regulation in the Diabetes Prevention Program. Diabetes Care. 2009;32(9):1583-1588.
3.         Rasmussen SS, Glumer C, Sandbaek A, Lauritzen T, Borch-Johnsen K. Progression from impaired fasting glucose and impaired glucose tolerance to diabetes in a high-risk screening programme in general practice: the ADDITION Study, Denmark. Diabetologia. 2007;50(2):293-297.
4.         DeFronzo RA, Abdul-Ghani M. Assessment and Treatment of Cardiovascular Risk in Prediabetes: Impaired Glucose Tolerance and Impaired Fasting Glucose. American Journal of Cardiology. 2011;108(3):3B-24B.
5.         Grundy SM. Pre-Diabetes, Metabolic Syndrome, and Cardiovascular Risk. Journal of the American College of Cardiology. 2012;59(7):635-643.
6.         Coppell KJ, Mann JI, Williams SM, et al. Prevalence of diagnosed and undiagnosed diabetes and prediabetes in New Zealand: findings from the 2008/09 Adult Nutrition Survey. The New Zealand medical journal. 2013;126(1370):23-42.
7.         Perreault L, Faerch K. Approaching Pre-diabetes. Journal of Diabetes and Its Complications. 2014;28(2):226-233.
8.         Lee M, Saver JL, Hong KS, Song S, Chang KH, Ovbiagele B. Effect of pre-diabetes on future risk of stroke: meta-analysis. British Medical Journal. 2012;344:11.
9.         Ford ES, Zhao GX, Li CY. Pre-Diabetes and the Risk for Cardiovascular Disease A Systematic Review of the Evidence. Journal of the American College of Cardiology. 2010;55(13):1310-1317.
10.       Rhee SY, Woo J-T. The prediabetic period: review of clinical aspects. Diabetes & metabolism journal. 2011;35(2):107-116.
11.       Khaodhiar L, Cummings S, Apovian CM. Treating Diabetes and Prediabetes by Focusing on Obesity Management. Current Diabetes Reports. 2009;9(5):348-354.
12.       Faerch K, Vaag A, Holst JJ, Hansen T, Jorgensen T, Borch-Johnsen K. Natural History of Insulin Sensitivity and Insulin Secretion in the Progression From Normal Glucose Tolerance to Impaired Fasting Glycemia and Impaired Glucose Tolerance: The Inter99 Study. Diabetes Care. 2009;32(3):439-444.
13.       Sheard NF, Clark NG, Brand-Miller JC, et al. Dietary carbohydrate (amount and type) in the prevention and management of diabetes - A statement by the American Diabetes Association. Diabetes Care. 2004;27(9):2266-2271.
14.       Amer Diabet A. Nutrition recommendations and interventions for diabetes - A position statement of the American Diabetes Association. Diabetes Care. 2008;31:S61-S78.
15.       Yeh GY, Eisenberg DM, Kaptchuk TJ, Phillips RS. Systematic review of herbs and dietary supplements for glycemic control in diabetes. Diabetes Care. 2003;26(4):1277-1294.
16.       Chepulis L, Al-Aubaidy H, Page R. Effects of selected antioxidant food extracts on postprandial glucose responses in healthy individuals. Functional Foods in Health and Disease. 2016;6(8):493-505.
17.       de Bock M, Derraik JGB, Brennan CM, et al. Olive (Olea europaea L.) Leaf Polyphenols Improve Insulin Sensitivity in Middle-Aged Overweight Men: A Randomized, Placebo-Controlled, Crossover Trial. Plos One. 2013;8(3):8.
18.       Perreault L, Pan Q, Mather KJ, et al. Effect of regression from prediabetes to normal glucose regulation on long-term reduction in diabetes risk: results from the Diabetes Prevention Program Outcomes Study. Lancet. 2012;379(9833):2243-2251.
19.       Perreault L, Temprosa M, Mather KJ, et al. Regression From Prediabetes to Normal Glucose Regulation Is Associated With Reduction in Cardiovascular Risk: Results From the Diabetes Prevention Program Outcomes Study. Diabetes Care. 2014;37(9):2622-2631.
20.       Jadhav RA, Hazari A, Monterio A, Kumar S, Maiya AG. Effect of Physical Activity Intervention in Prediabetes: A Systematic Review with Meta-analysis. Journal of physical activity & health. 2017:1-29.
21.       DeFronzo RA, Tripathy D, Schwenke DC, et al. Pioglitazone for Diabetes Prevention in Impaired Glucose Tolerance. New England Journal of Medicine. 2011;364(12):1104-1115.
22.       Ratner R, Goldberg R, Haffner S, et al. Impact of intensive lifestyle and metformin therapy on cardiovascular disease risk factors in the diabetes prevention program. Diabetes Care. 2005;28(4):888-894.
23.       Yudkin JS. "Prediabetes": Are There Problems With This Label? Yes, the Label Creates Further Problems! Diabetes Care. 2016;39(8):1468-1471.
24.       Tuomilehto J, Lindstrom J, Eriksson JG, et al. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. New England Journal of Medicine. 2001;344(18):1343-1350.
25.       Hamman RF, Wing RR, Edelstein SL, et al. Effect of weight loss with lifestyle intervention on risk of diabetes. Diabetes Care. 2006;29(9):2102-2107.

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