Diabetes and Stroke: Towards a Model of Primary Prevention in Neurology

In SoundMind Blog by Hannah McLane

Stroke is a significant public health concern: it is the second leading cause of death worldwide, and is a leading cause of permanent disability.  A population that has a particularly high risk for stroke is diabetics: in fact, one in eight diabetics will eventually suffer from a stroke, and having diabetes doubles one’s risk for stroke. Diabetes is highly prevalent in Fall River, Mass, which is our population of interest in this assignment: 11.3% of the population currently has diabetes and 7.0% has prediabetes. Every week in Massachusetts alone there are 38 cases of leg amputations, 22 deaths, and 5 new cases of blindness due to diabetes. Approximately 35% of the population of Fall River speaks Portuguese as their primary language, and there is a paucity of written material available for diabetics in Portuguese as well as a shortage of diabetes educators that speak Portuguese.

Hyperglycemia, and abnormalities in glucose metabolism in general, is detrimental to the brain: it increases one’s risk for stroke, causes small-vessel damage in the brain, and even increases one’s risk for dementia.2  Recent data has also shown that 30%-40% of patients coming into hospitals during acute stroke have hyperglycemia – most of them without a known history of diabetes.  A person’s 3-month history of blood-glucose levels can be measured with serum levels of Hemoglobin A1C (diabetes is defined as A1C>6.5%, and prediabetes is 6.0-6.4%).  A non-diabetic will have A1C levels of approximately 4-5.6%.

A high risk approach to this public health problem would be to wait until Portuguese-speaking residents of Fall River are diagnosed with diabetes (A1C>6.5%), and then subsequently treat them with diabetes medications at that point in time (such as Metformin or insulin).  A clinical scenario would be as follows: a patient comes in complaining of eating, drinking and urinating excessively (these are symptoms of diabetes), the doctor tests his/her A1C and blood glucose levels, and makes a diagnosis of diabetes. The doctor then counsels the patient to lose weight, exercise, eat whole grains, and take diabetes medication daily. Another aspect of this high-risk approach is waiting until a patient has complications of diabetes (e.g. kidney failure) to then diagnose and treat; in the high-risk approach, afterall, not all patients will be tested early enough to detect the diabetes before complications occur.

A population-based approach would be to target the entire Portuguese-speaking population in Fall River to shift the entire curve of A1C (blood sugar) levels to the left – in other words, aim to lower everyone’s blood sugar levels regardless of their baseline. One simple yet highly effective way to lower blood glucose levels is to increase fiber in the diet – e.g. eating more fruits, vegetables, whole grains, etc.  A population-based approach could be as follows: put a weekly “healthy eating tip” in the free Portuguese newspaper in Fall River with simple advice about increasing dietary fiber. To design these Tips appropriately, Portuguese-speaking diabetes educators in Fall River should be and asked about cultural eating habits (including what kinds of fiber-rich foods may be acceptable to this population).  For instance, most of the Portuguese-speaking population in Fall River is from the Azores, and beans are traditionally used in Azorean cooking, so reminding people that beans contain fiber would be a culturally-appropriate Tip.

A second prong of this population-based approach would be to go to local supermarkets and look at prices for whole-grain and fiber-rich foods: What are some of the specific barriers keeping this population from eating more fruits, vegetables, and fresh foods?  Is it the price, availability in the supermarket, the taste, the brand?  Poll people in the supermarket to better understand their food choices, and then attempt to make these fiber-rich foods more accessible. For example, one could ask the supermarket-owners to put these foods more towards the front of the store, or even put a colored sticker on foods that are rich in fiber — and promote the sticker idea in the weekly newspaper Tips.

The pros and cons of each approach are numerous. The high risk approach is beneficial in that it targets fewer people and thus requires less infrastructure and city-wide oversight in order to implement. Because it targets only specific people who have already developed the disease, they potentially might take the disease seriously and be more likely to change habits. This approach also has large individual benefit. The cons of the high-risk approach is that it doesn’t actually prevent the disease, so many of these patients will still have complications.  This can end up being quite costly –  a leg amputation alone costs $20,000-$60,000. It is also more difficult to change habits as one gets older, so compliance may be an issue the longer one waits to intervene. Furthermore, chronically taking pills such as Metformin for diabetes is not acceptable all people and some people may not be compliant with medications. This approach also has low population benefit, and could miss many people at risk (e.g. our population has many uninsured people that don’t regularly see physicians).

A population prevention strategy, in which we shift an entire distribution of exposure also has many pros and cons. The pros include that it potentially can benefit many people, even those that may not have access to physicians. It could be cost-saving if designed effectively (one year of Healthy Eating Tips costs $1300 to publish). Another benefit is that change can occur before physiological damage of hyperglycemia has begun (if one waits for diagnosis, organ damage  to kidney, eyes, or brain may have already occurred).  Lastly, it is beneficial in that it changes social norms: if all of the population is eating more fiber-rich foods, then no one is singled out.  Cons of the population strategy is that it could also be expensive to implement depending on how far one wants to take it (TV advertising, paying supermarkets, etc). It requires infrastructure (e.g. newpapers, delivery of newspapers, overseeing city-wide implementation), and whether or not it actually changes eating behaviors is not definite.  Patients may also be less motivated because if they haven’t gotten diabetes yet, they might not see why they need to change.  Thus we can see that there is not only one way to address this health concern but that we must take into account the varying aspects of each approach to come up with the most effective way to reach the maximum number of people.