Type 2 Diabetes in Men

Ecology term paper

Citation: Rob M. van Dam, MSc; Eric B. Rimm, ScD; Walter C. Willett, MD; Meir J. Stampfer, MD; and Frank B. Hu, MD., Dietary Patterns and Risk for Type 2 Diabetes Mallitus in U.S. Men. Annals of Internal Medicine, Volume 136, Number 3, pg. 201-209.

I. Background

a. What is diabetes?

Diabetes is a disease in which the body produces an insufficient amount of insulin, or none at all, resulting in hyperglycemia (elevated glucose levels in the blood stream). Insulin is a hormone that is produced by the pancreases and is essential for converting food into energy. The food we eat is broken down into glucose, which is essentially sugar in our blood. The cells in our body pick up the glucose in our blood stream and use it for energy and growth. However, in order for glucose to successfully enter the cells, insulin needs to be present. Analogous to this situation is a man trying to get into a locked room. The man would be glucose, the locked room would be our cells, and the absent key would be insulin. Without insulin, glucose would pass through our body without ever being converted into energy, and our cells would starve to death.

b. Type 2 Diabetes Mellitus

There are three types of classification for diabetes: type 1 diabetes, types 2 diabetes, and gestational diabetes. Type 2 diabetes is most common and is characterized by insulin resistance, in which insulin in the body becomes less effective at lowering the glucose levels in the blood. Unlike type 1 diabetes, a disease one is born with where the body cannot produce insulin, type 2 diabetes usually develops in adults. Development of type 2 diabetes in adults have been linked to lifestyle choices, dietary patterns, and genetics.

II. Dietary Patterns and Risk for Type 2 Diabetes Mellitus in U.S. Men

a. Summary

The objective of the study was to examine the link between major dietary pattern and the development of type 2 diabetes mellitus. Prior to this article, other studies examining the causes of type 2 diabetes could not separate the effects of diet from those of other risk factors, leaving the role of diet in the development of type 2 diabetes relatively unknown. Using a prospective cohort study design, 42, 504 male health professionals, without diagnosed diabetes, cardio vascular disease, or cancer, were given a 131-item semi-quantitative food-frequency questionnaire in 1986, 1990, and 1994. Every 2 years the participants were requested to give a medical update of any recent diagnosed diseases. Using a factor analysis based on the food questionnaires, the authors identified two major dietary patterns which they labeled "prudent" and "western". The "prudent" diet is characterized by higher consumption of vegatables, fruit, fish, poultry and whole grains. The "western" diet is characterized by a higher consumption of red meat, processed meat, French Fries, high-fat dairy products, refined grains, and sweets and deserts. The study was then adjusted for potential cofounders including body mass index (BMI), exercise, cigarette smoking, alcohol intake, and family history for diabetes.

b. Results

During the 12 year study, out of the 42, 502 participants, 1,321 were diagnosed with type 2 diabetes. The prudent diet pattern scores were linked to modestly low risk for type 2 diabetes, while the western diet pattern scores were linked to a relatively high risk of type 2 diabetes. The high risk for type 2 diabetes increased when the western diet was coupled with low physical activity and/or obesity. In the aggregate, the results of the study suggest that a western diatary pattern is associated with a substantial risk for type 2 diabetes in men.

III. Strengths

a. Design

The prospective cohort study, was the appropriate design considering the objective of the experiment: examining the link between type 2 diabetes and diatary pattern. The development of type two diabetes is gradual, and can take up to ten years in adults to develop. Given the nature of the disease, a prospective cohort study, that follows a group of similar people (cohorts) over a set amount of time, was the only appropriate design to produce valid results. Otherwise, subjects would have to retroactively recall their diet for the last ten years, which would of most certainly rendered invalid results. The 131-item semi-quantitative food frequency questionnaire were given to the participants in 1986, 1990, and 1994. The high rate of follow up reduced the presence of recall bias or bias due to a lack of follow ups.

b. Adjustment for potential cofounders

The objective of the experiment was to examine the causal link between dietary patterns and type 2 diabetes. However, since there are a number of other factors that contribute to type 2 diabetes, the experiment needed to take these cofounders into account so the causal connection between diet and type 2 diabetes could be examined in isolation. These cofounders included cigarette smoking, physical activity, body mass index, and medical history. To view the link between dietary patterns and type 2 diabetes in isolation, the authors needed to collect all information from the participants on all potential confounders. Then, they needed to take that data into account when doing their statistical analysis. This was accomplished by the participant answering a non-dietary assessment questionnaire at the beginning of the study in 1986, and biennially throughout the duration of the study. This questionnaire assessed weight, smoking status, and physical activity. Regarding the cofounder for medical history, the initial questionnaire sent to the participants required them to fill out their detailed medical history. Any participant that reported having diabetes, cardiovascular disease (myocardial infarction, angina pectoris, coronary artery surgery, or stroke), or cancer, were automatically excluded from the study at its conception. Participants would excluded throughout the study if they developed any of these medical conditions. Other potential cofounders such as alcohol or coffee consumption were calculated into the western dietary score. Those participants who left the majority of the questions blank on these questionnaires were also excluded from the study.

c. Sample group

The sample group is both a strength and a weakness for this study. The sample group consisted of 51, 529 male health professionals in 1986. These health professionals included dentists, veterinarians, pharmacists, optometrists, osteopathic physicians, and

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