Issues of Concern
Prevention of Type 2 Diabetes Mellitus
Type 2 diabetes mellitus is a chronic condition characterized by the impairment of insulin secretion within the body and insulin resistance. It is estimated that type 2 diabetes mellitus now affects more than 7% of adults in the United States and is most prevalent in elderly patients and specific ethnic groups.[5] In addition to creating a personal and economic burden on the patient, diabetes can lead to several long-term complications, including retinopathy, nephropathy, and other vascular complications leading to amputations. Furthermore, patients with type 2 diabetes mellitus are two to four times more likely to develop cardiovascular disease and experience a stroke in their lifetime.[5]
Due to these complications and the increasing prevalence and incidence surrounding type 2 diabetes mellitus, preventing this disease process has become increasingly important.[6] Several methods that have been proven to be successful in the prevention of type 2 diabetes mellitus type 2 include lifestyle modifications such as weight loss, increasing physical activity, and dietary changes.[6]
Weight Loss
Weight loss for the prevention of type 2 diabetes mellitus has shown to be an effective strategy as it has been found to improve insulin secretion and has been a suggested intervention for patients with diabetes who are overweight or obese. Evidence from several prominent studies has supported the notion that weight loss is associated with a decreased risk of developing type 2 diabetes mellitus.[5]
Of these is the United States Diabetes Prevention Program (DPP), one of the largest and most comprehensive lifestyle modification studies involving diabetes mellitus.[5][7] The DPP, described by Knowler et al. in 2002, randomly assigned 3,235 overweight adults with impaired glucose tolerance to either a lifestyle intervention, metformin, or a placebo group, with the lifestyle intervention arm aiming to have a reduction of 7% body weight in 24 weeks.[7][5]
For this intervention, participants were required to perform 150 minutes per week of moderate-intensity physical activity and were placed on a low-fat and calorie-reduced diet.[5] During this trial, participants lost an average of 7% body weight over one year, which was associated with a 58% reduction in the incidence of diabetes compared to the study's placebo arm (Figure 1).[5]
The DPP study demonstrated that patients diagnosed with diabetes in the United States who were either overweight or obese could effectively reduce diabetes risk with weight loss, which was also found in Asian populations. A study conducted in Japan designed for the prevention of type 2 diabetes by using lifestyle modifications included participants with impaired glucose tolerance testing, where patients were randomly assigned to a control group and an intervention group consisting of intensive lifestyle modifications with diet and exercise to achieve a BMI between 22 and 24.[8]
After a 4-year cumulative period, it was found that the incidence of diabetes was 9.3% in the control group, and 3.0% in the intervention group, with a risk reduction for developing diabetes of 67%, demonstrating that weight loss is a powerful prevention method.[8]
Physical Activity
Several studies have also determined that physical activity is crucial in preventing type 2 diabetes mellitus. A Finnish study called the Diabetes Prevention Study (DPS), which aimed to study the effects of lifestyle intervention as a method of preventing type 2 diabetes mellitus, randomly assigned 522 middle-aged adults who were in the overweight category and who had impaired glucose tolerance, to either an intervention group or a control group. The intervention group of the study included both diet and exercise with the goal of 30 minutes or more of moderate-intensity exercise each day, and a low-fat, low-dairy diet, as methods of weight loss.[5]
Compared to the control group, the intervention group had a 58% reduction in diabetes incidence over four years and was reported to have an average weight loss of approximately 4.2 kg. Though this study was not meant to analyze the exercise components of each participant specifically, the researchers found that participants who participated in more vigorous physical activity during their leisure time during the study period had a more significantly reduced risk of developing diabetes.[5]
The Diabetes Prevention Study describes that lifestyle modifications effectively reduce the risk of developing diabetes and that individuals who can continue and even challenge themselves with physical activity can even further reduce the risk of developing diabetes. These findings are supported by the physiology surrounding glucose metabolism during physical activity, as physical activity causes an increased uptake of glucose into muscles as they are actively used.[9]
Furthermore, as muscle activity increases in intensity, there is a greater reliance on carbohydrates to fuel these active muscles, leading to a lower fasting blood glucose for at least the first 24 hours after the individual has completed the exercise.[9]
This consumption of carbohydrates by active muscle groups and the effect of lowering the fasting blood glucose after physical activity explains the results demonstrated by some of the participants of the Diabetes Prevention Study, who were deemed to have even more success by undergoing more physical activity in their leisure time, outside of the prescribed 30 minutes of daily moderate-intensity exercise.
Prevention of Cardiovascular Disease
Type 2 diabetes mellitus is closely associated with other medical conditions such as hypertension, obesity, and hypercholesteremia which together form portions of what is known as metabolic syndrome (MS). Patients with metabolic syndrome are more likely to develop cardiovascular conditions and therefore have a higher mortality risk.[10]
As one of the leading causes of death in the United States, cardiovascular disease prevention methods have been studied consistently over time.[11] Various studies have determined that the lifestyle factors that influence cardiovascular disease the most are an individual's diet, physical activity, and tobacco use.
Diet greatly influences the management and potential progression of cardiovascular disease. Research has found that once coronary artery disease has been established, diet plays an integral role in furthering plaque deposition and influences endothelium reactivity, where both of these factors can largely predict cardiac events in the future. Prior evidence has determined that diets high in sodium, sugar-sweetened beverages, and meats positively correlate with cardiovascular morbidity and mortality.[11] This information analyzes specific diets to determine which dietary nutrients are best to prevent cardiovascular disease and improve mortality.
Diet Modifications
In addition to increasing physical activity (see below), dietary changes have been shown to benefit weight loss and the prevention of type 2 diabetes mellitus. Dietary modifications are an important aspect of diabetes prevention largely because they are associated with improved glycemic control.[1] In conjunction with increased physical activity, healthy diet habits can increase weight loss, which has been proven an effective strategy for diabetes prevention. However, in terms of diets, specific types allow for better glycemic control. A systematic review that analyzed 48 articles regarding dietary modifications for diabetes prevention determined that diets such as the Mediterranean diet and the Dietary Approaches to Stop Hypertension (DASH) diet were both associated with significant diabetes incidence risk reductions.[12]
In this review article, the Mediterranean Diet consisted of fish, seafood, fruits, nuts, vegetables, and legumes, with moderate alcohol consumption. This review which analyzed five studies, determined that for diabetes incidence, there was a range from 9% risk reduction to 25% risk reduction, meaning that the incidence of diabetes was reduced within a range of 9 to 25% when this diet was initiated.[12] The other diet which has been recommended is the DASH diet, which is defined as ten total food groups, and was developed to target hypertensive patients.[12]
Though this diet was initially targeted toward patients with hypertension, a meta-analysis of various studies using the DASH diet has also been determined to have a relative risk of 0.84, meaning that there is a decreased risk of developing diabetes mellitus when using this diet as well.
As mentioned above, the Mediterranean diet and the DASH diet are two of the most studied for both primary and secondary prevention of cardiovascular disease.[11] For the Mediterranean Diet, a large volume of literature details its beneficial health effects.[11]
The most notable of these is the Lyon Diet Heart Study which studied patients recovering from a myocardial infarction (MI) and reported a near 70% reduction in further cardiovascular events when switching to the Mediterranean diet. As for the DASH diet, recent trials have demonstrated beneficial effects on blood pressure and improvements in other cardiovascular risk factors.
The DASH diet is described as four or more cups of fruits and vegetables each day, low-fat dairy products, 3 ounces of whole grains each day, 7 ounces total of fish per week, less than 1,500 mg of sodium each day, and less than 450 calories of sugar-sweetened beverages each week. A meta-analysis of 6 studies that used the DASH diet determined that the risk of coronary artery disease was reduced by 21%, and the risk of stroke was also reduced by 21%, demonstrating that the DASH diet has the potential to improve the risk of developing these two conditions significantly.[13]
Vegetarian diets of various types are associated with a lower prevalence of diabetes. A subset of the Adventist HealthStudy-2, which included over 60,000 subjects, showed a lower prevalence of diabetes in vegetarians than non-vegetarians. Vegans and lacto-ovo vegetarians had a nearly one-half decrease in the prevalence of diabetes, even after controlling for lifestyle characteristics and BMI (Table 1).[14]
Table 1. Types of vegetarian diets and odds of diabetes as compared to non-vegetariansafter controlling for lifestyle characteristics and BMI from the Adventist Health Study-2 study[14]
| N=60,903 (38,469 women, 22,434 men) |
Odds Ratio |
95% Confidence Interval |
| Vegan |
0.51 |
0.40–0.66 |
| Lacto-Ovo Vegetarian |
0.54 |
0.49–0.60 |
| Pesco-vegetarian |
0.70 |
0.61–0.80 |
Physical Activity
Physical activity, as it has been studied for cardiovascular health benefits, is defined as the movement by skeletal muscle that causes an increase in energy expenditure compared to rest. Decreasing cardiac disease risk factors is important for patients with diabetes. Physical activity has been shown to improve cardiovascular risk factors, such as hypertension, coronary artery calcium, and lipids, and has been associated with a reduced risk of coronary artery disease or heart failure.[11]
A meta-analysis and review completed in 2016, which was based on cardiac rehabilitation programs, determined that these programs relative risk of 0.74 for cardiovascular mortality and had a relative risk of 0.82 for hospitalization. Another meta-analysis of 44 studies that were randomized controlled trials showed that aerobic exercise reduced blood pressure in both normotensive and hypertensive individuals. As these and various other studies have demonstrated, there is significant evidence of the benefit of physical activity. Therefore, the American Heart Association recommends a minimum of 30 minutes of moderate to intense exercise at least five days out of the week.[11]
Tobacco Cessation
Tobacco has long been associated with cardiovascular deaths, and it has been estimated that up to 10% of cardiovascular deaths worldwide in adults aged 30 years or older can be attributed to tobacco use. Tobacco smoke itself contains approximately 98 components that are hazardous when inhaled.[11]
It has been determined that tobacco smoke causes endothelial cell dysfunction, increases lipid oxidation, and causes activation of both pro-inflammatory and pro-coagulation states. A meta-analysis completed in 2021 analyzed nine studies that compared tobacco users and cardiovascular disease and stroke. It was found that smoking cessation was associated with significantly lowered mortality from cardiovascular disease, despite some post-cessation weight gain.[15]
In conclusion, lifestyle modifications for both type 2 diabetes mellitus and coronary artery disease do overlap in terms of diet changes and increasing physical activity. Both the DASH diet and Mediterranean diets have shown positive evidence of reducing the incidence of both type 2 diabetes mellitus and coronary artery disease.
Additionally, physical activity of approximately 30 minutes of moderate to intense exercise reduces the risk of developing both type 2 diabetes and coronary artery disease. Weight loss has specifically been shown to reduce the incidence of diabetes as it reduces insulin resistance, whereas tobacco cessation has been correlated with a reduction in coronary artery disease risk as it decreases pro-inflammatory and endothelial injury.[5][11]
Clinical Significance
Type 2 diabetes mellitus and cardiovascular disease are two of the most common chronic health conditions, leading to significant mortality rates and financial burden. The various lifestyle modifications indicate changes that patients can make in their daily lives and allow patients to feel empowered to take control of their medical conditions.
Patients diagnosed with type 2 diabetes mellitus are more at risk for developing microvascular disease, a sequela of this condition. However, weight loss through diet and physical activity has been shown to significantly reduce the incidence of diabetes, reducing the patient’s chance of developing nephropathy, retinopathy, and neuropathy.[5]
In patients diagnosed with type 2 diabetes mellitus, reducing the severity of diabetes and preventing its sequela ultimately increases the patient’s quality of life and long-term health. Overall, these preventative methods aim to reduce the incidence of diabetes mellitus, which would significantly reduce chronic disease and prevent patients from experiencing the hardships associated with diabetes, both in terms of health and finances.[5][2]
Cardiovascular disease is closely associated with type 2 diabetes mellitus as the pathophysiology behind diabetes mellitus induces changes in vessels that leads to a greater likelihood of developing both of these co-morbid conditions.[10] Like type 2 diabetes, patients diagnosed with cardiovascular disease will have the ability to improve their risk of worsening or progressive disease through diet changes, physical activity, and tobacco cessation.[11]
Dietary changes, such as certain vegetarian diets, the Mediterranean diet, or incorporating the DASH diet, have been shown to reduce the risk of cardiovascular events and allow patients to make these changes themselves.[11][13] Tobacco cessation is a key lifestyle modification that allows patients to improve their cardiovascular risk, reduce their risk of developing chronic lung conditions, and enhance their overall quality of life.[11][15]
These preventative methods will allow patients to control their medical conditions more than medications, surgical interventions, or procedures. They are changes that can be made in the patient’s home environment that significantly impact the overall progression of their disease process and the sequela surrounding the conditions.
Enhancing Healthcare Team Outcomes
Type 2 diabetes mellitus and coronary artery disease are some of the leading causes of mortality in the United States and globally. Type 2 diabetes mellitus is impaired insulin secretion, leading to increased blood glucose[5]. Significant evidence demonstrates that patients diagnosed with type 2 diabetes mellitus are more likely to develop coronary artery disease. However, there are multiple prevention methods, and as healthcare professionals, it is essential to provide patients with accurate information regarding preventing these chronic conditions.
One of the most influential studies completed regarding type 2 diabetes prevention with the prevention strategy of weight loss was the United States Diabetes Prevention Study (DPS), which randomly assigned over 3,000 overweight adults with impaired glucose tolerance to groups to either receive placebo, metformin or join the lifestyle interventional group.[5]
It was found that with a lifestyle intervention of a low-calorie and low-fat diet and moderate-intensity exercise for 150 minutes each week, patients in the lifestyle intervention group demonstrated a 67% reduction in the risk of developing type 2 diabetes mellitus. This study showed that patients could participate in prevention methods, significantly reducing their risk.
Clinicians are responsible for informing their patients about their risk of developing type 2 diabetes mellitus as well as prevention methods and how these methods would impact their long-term health. Other health professionals, especially nurses, nurse practitioners, and physician assistants, are responsible for sharing this information and working with patients on these lifestyle changes.
Coronary artery disease is a co-morbid condition that poses life-threatening consequences of disease sequelae, and like type 2 diabetes mellitus, It is a condition that can be managed with prevention methods. Specifically, the Lyon Diet Heart Study demonstrated that patients who have experienced a myocardial infarction in the past had a 70% reduction in risk after starting the Mediterranean diet.[11]
Thus prevention strategies involving diet changes should be communicated to patients at higher risk of developing this co-morbidity. Physicians should be educated in the physiology behind preventative methods to recommend the best patient strategies. Other health professionals should also be aware of these so they can educate and provide the best care for patients.
Type 2 diabetes mellitus and coronary artery disease are associated with some of the highest mortalities. However, preventative strategies have been extensively studied and have demonstrated significant risk reductions in these conditions. Health professionals should be well informed regarding the benefits of these prevention methods to improve patient outcomes.
Lifestyle Modification for Diabetes and Heart Disease Prevention
