The long time distance from high risk to the onset of clinically diagnosed T2D offers an opportunity to prevent the disease. The Finnish Diabetes Prevention Study (DPS) showed the first time that T2D can be prevented by lifestyle changes, which included increased physical activity, dietary changes and weight reduction (Tuomilehto et al. 1997). Several studies have identified that healthier lifestyle could prevent T2D in people at risk (Yamaoka & Tango 2005, WHO 2016c).
Some randomized controlled clinical trials observed that both lifestyle modification and pharmacological treatment may reduce the incidence of T2D among the people with IGT (Gillies et al. 2007). Because obesity is one of the most important risk factors for the development of diabetes, most of the studies included individuals with obesity and IGT as their study group and the majority of them suggested lifestyle intervention based on diet and exercise for the prevention of T2D. These studies proved that T2D can be prevented or at least the onset can be delayed by lifestyle modification (Saaristo et al. 2010) and pharmacological treatment (Gillies et al. 2007).
Lifestyle intervention seems to have a larger effect compared with pharmacological treatment (Knowler et al. 2002). It is also found that the impact of genetic and familial risk factors of diabetes could be overcome by lifestyle changes (Uusitupa et al. 2011). Weight reduction should be the primary target intervention for the reduction of diabetes risk (Hamman et al. 2006) as obesity is the strongest predictor of diabetes (Wang et al. 2005, Narayan et al. 2007). For severely obese individuals, along with lifestyle and pharmacological interventions, surgical intervention has been found to be effective. It is observed that bariatric surgery is highly effective for extremely obese individuals (Merlotti et al. 2014).
A systematic review examined the association between physical activity of moderate intensity and the risk of T2D. The study concluded that physical activities of moderate intensity, such as brisk walking, can reduce the risk of T2D (Jeon et al. 2007). Evidence suggests that moderate to intensive level exercise is effective for the reduction of abdominal obesity, which in turn will reduce the risk of T2D and CVD (Shi et al. 2013, Palermo et al. 2014). Regular, at least 30 minutes moderate intensity activity is recommended for the prevention of diabetes (WHO 2016c). A prospective cohort study was conducted among 4554 women with the history of GDM from the Nurses' Health Study II. The intention of the study was to examine the role of physical activity and other sedentary behaviors in the progression from GDM to T2D and the study found that physical activity reduced the risk of T2D, even in highly susceptible individuals (Bao et al. 2014).
Several studies have investigated the effectiveness of the drug therapy, including oral hypoglycemic agents, anti-obesity agents, antihypertensive agents, statins, fibrates, and estrogen replacement agents on either delay or prevention of T2D. It is observed that only oral hypoglycemic and anti-obesity agents have a significant effect on T2D (Lauritzen et al. 2007). Orchard et al.
(2005) found that lifestyle intervention and metformin therapy have a potential to reduce the onset of metabolic syndrome and T2D.
2.2.2 Diagnosis of T2D
In Finland, the Current Care Guidelines give instructions for prevention and screening of diabetes as well as for appropriate treatment. The Finnish Diabetes Risk Test (FINDRISK) is used to distinguish the high-risk individuals from the target population. All high-risk individuals should be screened for T2D to make the diagnosis and to start the treatment as early as possible (Finnish
Diabetes Association 2003). It is observed that the difference between diagnosis and original onset of diabetes is on average 7 years (Saudek et al. 2008). According to the Finnish Diabetes Association, in 2016 there were almost 150000 people undiagnosed in Finland.
The most utilized method to diagnose the diabetes is the estimation of fasting glucose level and glucose level two hours after a glucose load, but WHO has also recommended glycated hemoglobin (HbA1c) measurement (HbA1c > 7%) for the confirmation of diagnosis of diabetes (WHO 2011).
According to the American Diabetes Association (2016) there are 4 options for the diagnosis of diabetes (Table 1) : 1) Fasting plasma glucose (FPG) ≥ 126 mg/dl (7.0 mmol/l), where fasting means no caloric intake for at least 8 hours, 2) Measurement of 2-h postprandial glucose (PG) ≥ 200 mg/dl (11.1mmol/l) during an OGTT, 3) Measurement of HbA1c ≥ 6.5% (48 mmol/l) and 4) In a patient with classic symptoms of hyperglycemia or hyperglycemic crisis, a random plasma glucose ≥ 200 mg/dl (11.1 mmol/l) (American Diabetes Association 2016). The diagnostic criteria of T2D in Finland are in accordance with the criteria of the American Diabetes Association (ADA) 2016 guidelines (Current Care Guideline 2016).
Table 1: Criteria for Diabetes Diagnosis (American Diabetes Association 2016).
Parameters Unit
Fasting plasma glucose (FPG) ≥ 126 mg/dl or 7.0 mmol/l
2-h Postprandial glucose (PG) ≥ 200 mg/dl or 11.1mmol/l
HbA1c ≥ 6.5%
Random plasma glucose ≥ 200 mg/dl or 11.1 mmol/l
2.2.3 Treatment of T2D
To prevent the complications of T2D and to ensure good quality of life, it is important to implement a suitable treatment and systematically monitor patient’s condition. A prospective observational study was conducted among 23 hospital based clinics in England, Scotland, and Northern Ireland to examine the association between glycaemia over time and the risk of macrovascular or microvascular complications in patients with T2D. The study found that there is a strong association between incidence of clinical complications and glycaemia. According to the study, each 1% reduction in updated mean HbA1c was associated with 37% reductions in risk for microvascular complications (95% CI 33% to 41%, P < 0.0001) and 14% for myocardial infarction
(95% CI 8% to 21%, P < 0.0001) (Stratton et al. 2000). Another study examined the relationship between diabetic complications and age, sex, duration, mode of therapy, body weight, control of blood glucose, blood pressure, and serum triglycerides and cholesterol among T2D patient in Japan.
The study found that control of blood glucose, mode of therapy, and duration were correlated with microvascular complications and macrovascular complications were strongly related to aging and blood pressure. According to the study along with good glycemic control, sufficient antihypertensive therapy is also necessary for treating T2D patients (Meeuwisse et al. 2008).
According to the Finnish Current Care Guidelines (2016), lifestyle changes are the mainstream treatment of T2D (Figure 1). Starting with lifestyle change and medication such as metformin is suggested for early-diagnosed diabetes patient. The treatment is tailored according to the individual patient’s life situation, such as early DM, chronic DM > 10 years, obese patient, elderly patient, professional drivers or patient with kidney impairment. Insulin therapy is also appropriate as a temporary first line therapy if hyperglycemia is found to be causing severe symptoms of T2D. The insulin dosage can be adjusted based on plasma glucose concentration in the morning or evening, the goal is to get the concentration of fasting plasma glucose value at the right level using either intermediate acting insulin such as, neutral protamine hagedorn (NPH) or long acting insulin 1-2 times a day. When treating elderly diabetic patient, the possibility of drug interaction and hypoglycemia needs to be considered (Current Care Guideline 2016).
Figure 1. An example of treatment plan for early diabetes mellitus by Finnish Current Care Guidelines 2016 (Current Care Guideline 2016).
According to the Current Care Guidelines, the treatment goals in Finland for T2D are HbA1c below 7%, fasting glucose concentration less than 7 mmol/l, 2-hour post-prandial glucose level below 10 mmol/l and LDL cholesterol less than 2.5 mmol/l (Table 2) (Current Care Guideline 2016). The glycemic control targets by the Finnish Current Care Guidelines are in accordance with the recommendations of the American Diabetes Association (ADA) 2016 guidelines.
Table 2. Blood Glucose & LDL Cholesterol Targets for Adults with Diabetes (American Diabetes Association 2016, Current Care Guideline 2016).
Parameters Target
HbA1c ˂ 7%
Fasting plasma glucose (FPG) ˂ 7 mmol/l
2-h Postprandial glucose (PG) ˂ 10 mmol/l
LDL cholesterol ˂ 2.5 mmol/l
However, both according to the guidelines of ADA and the Finnish Current Care Guidelines, targets can be tailored based on age, life expectancy, comorbid conditions, diabetes duration and hypoglycemic status. In case of patient aged more the 75 years, the main goal of treatment is to improve the quality of life, to promote self-reliance and to get free of symptoms. Although targets can be flexible, it needs to be remembered that keeping HbA1c level below or around 7% reduces the risk of microvascular complications (American Diabetes Association 2016, Current Care Guideline 2016).