Article by Bruce Dopler, MD
Neurologist, Neurology Center of South Delaware; Tidal Health Nanticoke
Addressing medical conditions such as diabetes, hypertension, lipid management, sleep apnea, and atrial fibrillation will also have a major impact on stroke prevention. In addition to stroke prevention, these strategies help with overall brain health, which may also have an impact on neurological degenerative diseases such as Alzheimer’s disease.
There has been a trend towards reduction of stroke incidence from 8.7% in the 1960s to 5.0% in the 2000s. This is thought to be secondary to improved blood pressure control and the use of antiplatelet medications.1 The optimal stroke prevention strategy for an individual depends on the underlying etiology of their stroke. In general, management of vascular risk factors, including management of diabetes, smoking cessation, lipid management, hypertension management, as well as lifestyle modification provide the foundation for prevention of stroke. Lifestyle factors such as low-sodium, Mediterranean diet and physical activity may provide the greatest benefit for primary and secondary prevention. Addressing these factors also helps maintain optimal brain health.
Physical inactivity has been a well-defined and modifiable risk factor for cardiac disease and stroke. In the Northern Manhattan Stroke Study, a dose response relationship showing more intensive physical activity had greater stroke reduction compared to light and moderate physical activity. It is felt that exercise itself plays a part through potential factors such as anti-inflammatory effects, but also the modification of other associated risk factors such as reduction in blood pressure, body mass index (BMI), lipid levels and better diabetic control.4
Diet and nutritional studies have identified the protective effects from stroke by regular consumption of fish,5 high consumption of fruit and vegetables,6 following a Mediterranean diet,7 and the Dietary Approaches to Stop Hypertension (DASH) diet.8 The Mediterranean diet is high in the monounsaturated/saturated fat ratio, using olive oil as a main cooking ingredient. Consumption of other traditional foods high in monounsaturated fats such as tree nuts and other plant-based foods including fruits, vegetables, legumes whole grains, and cereals; increased consumption of fish; low consumption of meat and meat products; and discouraging the consumption of red and processed meats have been shown to be beneficial. Low alcohol consumption should be encouraged. The vascular-healthy diet moderates the consumption of milk and dairy products, and discourages soda drinks, pastries, sweets, commercial bakery products and spread fats. It also emphasizes consumption of less than 1500 mg of sodium per day. The reader is encouraged to go the American Heart Association website (https://www.heart.org) for further recommendations.
drink (women) be counseled to eliminate or reduce their consumption of alcohol to reduce stroke risk.1 Acute ischemic stroke hospitalization is higher among cannabis users, and the US Centers for Disease Control and Prevention identified that young adults with recent cannabis use have higher odds of stroke compared with nonusers.12 In patients with stroke or TIA who have a substance use disorder (drugs or alcohol), specialized services are recommended to help manage this dependency.
Type 1 diabetes is an autoimmune disorder that results in absolute insulin deficiency. Type 2 diabetes results from progressive impairment of insulin sensitivity and pancreatic insulin secretion. The pathophysiology of prediabetes is the same, with the only difference in the blood sugar level.
In Delaware, more than 98,000 individuals (about the seating capacity of the Los Angeles Memorial Coliseum), reported that they had been diagnosed with diabetes. In 2017, approximately 95,000 Delawareans reported that they had been diagnosed with prediabetes. Delaware’s prevalence of diagnosed diabetes, 13%, is greater than the national average of 11%.13 Diabetes prevalence is increasing in Delaware: from 2002 to 2019 Delaware’s adult diabetes prevalence rate rose from 8% to 13%, and at the projected rate it is estimated to be over 121,000 residents in the State of Delaware by 2030. 14
Diabetes increases the risk of stroke nearly three-fold and disproportionately affects the elderly and minority population.15 The duration of diabetes increases the risk of stroke by 3% per year.16 Prediabetes is present in approximately 30% of patients with acute ischemic stroke.17 Progression of prediabetes to diabetes can often be prevented by diet, weight control and exercise.
Despite the fact that diabetes is a disease having its pathophysiological effects related to impaired blood glucose control, there has been extremely limited data to support tight glucose control and the reduction of stroke risk for other cardiovascular events. In the Action to Control Cardiovascular Risk and type 2 Diabetes (ACCORD) study, patients with a mean hemoglobin A1c of 8.1% assigned to intensive glucose control with a target hemoglobin A1c of less than 6 were compared to a standard control group with hemoglobin A1c of 7.0-7.9. The study was stopped secondary to higher mortality rates in the intensive treated group. There was no difference in the risk of nonfatal stroke.18 Further studies are needed.
In patients who have had an ischemic stroke or TIA and have diabetes, the goal for glycemic control should be individualized. This should be based on the risk for adverse events, patient characteristics, and patient preferences. For most patients, achieving a hemoglobin A1c of 7% is recommended to reduce the risk of microvascular complications. The American Diabetes Association (ADA) have revised their algorithms for the management of type 2 diabetes. An evidence-based consensus report by the ADA and the European Association for the Study of Diabetes recommends metformin and comprehensive lifestyle changes as the first-line therapy.19 Because of new classes of glucose lowering medications that also prevent clinical vascular disease, the ADA recommends that in patients with ischemic strokes, glucagon-like peptide 1 (GLP-1) receptor agonists should be added to metformin, independent of baseline hemoglobin A1c. When concern for heart failure or chronic kidney disease predominates, the addition of a sodium glucose cotransporter 2 inhibitor to metformin is recommended. Through shared decision making, the treating provider should help the patient decide if the GLP–1 receptor agonist or the sodium glucose co-transporter 2 inhibitor is right for them. Costs, side effects, desired weight loss, aversion to injection therapy, and desire to reduce risk for hypoglycemia are factors that should be weighed in this discussion.
The degree of blood pressure lowering appears to be more important for the risk reduction of stroke than the class of antihypertensive agent used.24 The recommended threshold of blood pressure greater than 130/80 mmHg for starting hypertensive medication is due to the baseline blood pressure in patients of cerebrovascular disease studied in the above mentioned trials. There are, however, some unanswered questions concerning blood pressure management. Optimal blood pressure target for the very elderly population and for those individuals with extensive small vessel disease is unknown. The optimal blood pressure target for patients with diabetes and stroke and the optimal timing to begin blood pressure lowering after stroke need further study.
There are other prevention strategies for specific stroke types that go beyond the scope of this article. The reader is advised to read the American Stroke Association guidelines, which are continually updated, for specific recommendations.
Risk factor modification is vital for both primary and secondary stroke prevention. In order to achieve this auspicious goal, clinicians and patients must work together to create a comprehensive prevention and treatment plan. Communicating the importance of lifestyle modification and medical compliance is vital. The rewards of successfully making these changes are great, not only in stroke prevention, but in improving overall brain health, and preventing cognitive decline and allowing patients to remain independent and productive.