SCREENING REFERENCES FOR INSULIN RESISTANCE
American Diabetes Association Recommendations
Common Laboratory Screening Measures
Common Obesity Measures
FAO/WHO Carbohydrate Recommendations
Food Pyramids
Research methods to detect Insulin Resistance
Syndrome X
Web Sites: Health Care Sites for Consumers
Web Sites: Major Organizations

ADA Dietary Recommendations:

1.  Eat a variety of foods
2.  Follow the diabetes food guide pyramid  for guidelines on what and how much to eat. People with diabetes have the same food needs as people without diabetes.
3.  The diabetes food guide pyramid is similar to the one commonly seen on cereal and bread products. There are two major differences; starchy vegetables like green peas, corn and potatoes were moved out of the Vegetable Group and put into the Grains/Beans and Starchy Vegetables group. The other major change is that cheese was moved out of the Milk Group and is now in the Meat & Others Group.
4.  The amounts needed from each of the food groups is as follows:
Grains, Beans, and Starchy Vegetables - 6 or more servings per day
Fruits - 3-4 servings per day
Vegetables - 3-5 servings per day
Meat & Others - 2-3 servings per day
Milk - 2-3 servings per day 
Fats and Oils - only in small amounts 
Sweets - only once in a while
5.  Keeping a food record for a day or two, and then comparing the number of servings you eat to the number recommended by the diabetes food guide pyramid will tell you whether you are eating too much or too little of any of the food groups.
6.  Also, remember that the recommended number of servings is for the whole day, so you might want to divide the total number by 3 to see the amount needed per meal. For example, 3-4 servings of fruit per day means 1 per meal or snack, spread throughout the day.
7.  'Control carbohydrates'
8.  Carbohydrates include both starches and sugars. The total amount of carbohydrate is more important than the source of carbohydrate. Carbohydrates can be either refined and processed such as in soft drinks and candy, occur naturally such as in milk and fruit, and can be found in pasta, bread, rice, dried beans and peas, and starchy vegetables such as potatoes, corn or green peas.
9.  In other words, carbohydrate in the form of cookies doesn't affect your blood sugar any differently than carbohydrate from rice. However, carbohydrate foods in the form of grains, fruits or milk have vitamins, minerals and fiber, while sugary foods such as cookies have little nutritional value and are often high in fat.
Therefore, the majority of carbohydrate you consume should come from the grains, fruit or milk groups. It's okay to eat high-sugar foods, but they must be substituted for other carbohydrates, rather than just added to your meal plan. One serving of grains, fruit or milk provides about 15 grams of carbohydrate and is often referred to as 1 carbohydrate choice. For most people, 45-75 grams of carbohydrate per meal, and no more than 15-30 grams of carbohydrate per snack is a reasonable goal. However, your meal plan should be individualized to meet your specific needs, preferably by a registered dietitian.
ADA Recommendations: http://www.diabetes.org/virtualgrocery/mealplanning.asp
AHA Recommendations
http://www.americanheart.org/presenter.jhtml?identifier=4665
Alternative Food Pyramids

Common Laboratory Screening Measures
Criteria for the Diagnosis of Diabetes Mellitus
Normoglycemia IGF or IGT Diabetes Mellitus
Impaired Glucose Tolerance
FPG < 110mg/dl FPG > 110 and < 126 mg/dl (IFG) FPG >126 mg/dl
 2 hr PG <140mg/dl 2 hr PG >140 and < 200 mg/dl (IGT) 2hr PG  >200 mg/dl
Symptoms of DM and random plasma glucose concentration > 200 mg/dl
Sources
http://www.fpnotebook.com/END7.htm
Tight Diabetes Control
http://www.diabetes.org/main/type1/medical/blood_sugar/default3.jsp

Hemoglobin A1c

Source: http://www.mydiabetes.com/
[Articles Section: How Food Affects Blood Glucose Levels
What is it ?
http://medweb.bham.ac.uk/easdec/prevention/what_is_the_hba1c.htm
http://www.diabetes.org/main/type1/medical/blood_sugar/glyc_hemoglobin.jsp
http://www.geocities.com/diabeteschart/hba1ctest.html
Comparison Charts
http://www.geocities.com/diabeteschart/bloodsugarchart.html
http://www.pharmacie.de/info/blutwerte/hbac1c.html

Lipid Screening
Lipid Screening: Cholesterol and HDL Levels
Total cholesterol
  <200 mg/dL = Desirable blood cholesterol
200 to 239 mg/dL =Borderline-high blood cholesterol
240 mg/dL and over =High blood cholesterol
HDL cholesterol
  < 35 mg/dL  =  Low HDL cholesterol
Source American Heart Association: http://www.americanheart.org/presenter.jhtml?identifier=1200000
http://216.185.112.5/presenter.jhtml?identifier=548
http://216.185.112.5/presenter.jhtml?identifier=183

Lipid Screening: Triglycerides
Normal triglycerides
Less than 200 mg/dL
Borderline-high triglycerides
200 to 400 mg/dL
High triglycerides
400 to 1000 mg/dL
Very high triglycerides
Greater than 1000 mg/dL
These are based on fasting plasma triglyceride levels.
http://216.185.112.5/presenter.jhtml?identifier=4778
Source American Heart Association: http://www.americanheart.org/presenter.jhtml?identifier=1200000

Common Obesity Measures
Body Mass Index and Physical Obesity Measures
BMI and Truncal Obesity
Body mass index (BMI) is measure of body fat based on height and weight that applies to both adult men and women.
The BMI is a measurement of height and weight considered highly accurate and easily obtained.  during a routine office visit. The BMI has been proven useful for epidemiological research, and individuals can determine their BMI by doing their own measurements and calculations.
Calculate your Body Mass Index
BMI Categories
Classification
BMI
Underweight
<18.5
Healthy Weight
18.5 to 24.9
Overweight
25.0 to 29.9
Class I obesity
30.0 to 34.9
Class II obesity
35 to 39.9
Class III obesity
40.0 or higher.
Truncal  (or abdominal) is a convenient way for clinicians to identify IR (Bernstein (1997, p 375) identifies truncal obesity (also called central or visceral obesity) as a form of obesity, in which the circumference of the waist is greater than the circumference of the hips (in males) or greater than 80% of the hip circumference in females.
Truncal obesity is associated with hyperinsulinemia and metabolic syndrome X. (Bernstein, p 375).
Two different measurements can be taken:
Waist circumference alone has been associated with abnormal metabolic health indicators. "A waist circumference > 35 inches in a woman is a critical threshold leading to metabolic complications. ACCEA/ACE Obesity Position Statement, 1998, p 308).
The Waist-to-Hip Ratio (WHR) is an extension of that, using the same measurements
How to determine your waist-to-hip ratio (WHR)
a. Measure around the smallest part of your waistline – don't pull in, just stand relaxed.
b. Next, measure your hips at the largest point. 
c. Then, divide the waist measurement by the hip measurement.
http://www.americanheart.org/presenter.jhtml?identifier=4489

FAO/WHO Carbohydrate recommendations

Some Dietary Recommendations. Source: FOA/WHO Joint Expert Consultation. (1997). Carbohydrates in Human Nutrition.
http://www.fao.org/es/esn/index_en.stm
http://www.fao.org/docrep/W8079E/W8079E00.htm
Components of 
dietary energy
saturated fatty acids, <10% of total energy
Omega 6 polyunsaturated fatty acids, <10 % of total energy
Protein, 10-20% of total energy
Carbohydrate and cist-monounsaturated fatty acids, for the remainder
Carbohydrate 
Issues
Low glycemic index foods and those rich in soluble fiber recommended
Vegetables, fruits, pulses and cereal-derived foods preferred
Sucrose <10% total energy acceptable in certain circumstances
Timing of intake essential for those on insulin
Special 'diabetic' and
'dietetic' foods
Non-alcoholic beverages sweetened with non-nutritive sweeteners are useful
Other special foods not encouraged
No particular need of fructose and other 'special' nutritive sweeteners over sucrose

Commonly Used Research methods to detect IR
a.)Euglycemic insulin clamp:
One of the most widely accepted research method or 'gold standard' in the review articles available is the euglycemic insulin clamp technique.  "Exogenous insulin is infused, to maintain a constant plasma insulin level above fasting, while glucose is fixed at a basal level by infusing glucose at varying rates" The glucose infusion rate is increased when the plasma glucose level falls, and the rate is rebalanced to return the plasma glucose levels to basal levels.  The description continues:

The total amount of glucose infused over time (M value) is an index of insulin action on glucose metabolism. The more glucose that has to be infused per unit time, then the more sensitive the patient is to insulin. Conversely, the insulin-resistant patient requires much less glucose to maintain basal plasma glucose levels.
The advantages to this test are that the effect of insulin on fuel metabolism can be found without the confounding effects of c hypoglycemia or hyperglycemia, or endogenous insulin secretion.. Other events can be studied, such as the regulation of glucose and glucose uptake, inhibition of lipolysis, and changes in protein metabolism..  Limitations of this method are: several doses of insulin might be needed, and a steady state must be achieved for each dose. Complexity and cost in addition to the inability to reproduce physiological conditions limit usability of this test. The test is much too involved for use by clinicians in workplace.
b.) The Minimal Model
Bergman developed the minimal model to develop a more practical method for measuring insulin resistance. Glucose and insulin are sampled frequently during an intravenous Glucose Tolerance Test (GTT), and a computer generated value becomes the index of insulin sensitivity ((called Si ) The acute insulin release (AIR), in response to glucose can also be determined.  The test appears to correlate well with the euglycemic insulin clamp in nondiabetic subjects, but the accuracy deteriorates in diabetes, as it is proposed the immediate plasma insulin response is diminished.  "The procedure focuses on glucose, and not other insulin-sensitive fuels and only looks at net effects on glucose metabolism.  The individual roles of peripheral and hepatic glucose metabolism are not separated" The viewpoint on this test is that it is not useful for the clinician, because of the cost, time involved, and the complexity of the sampling procedure.
c.)Fasting Plasma Insulin Levels:
"One limitation in the measurement of fasting insulin is an overlap between insulin resistant individuals and normal individuals. Another limitation of this test is the lack of standardization and differences between labs.

If the assay for fasting insulin was reliable, it would be useful to detect insulin resistance early…before clinical disease appears….we do not recommend routine screening of patients using fasting insulin measurements because of the following liabilities: the problems with assay procedures, the inability of the measurement to accurately indicate the presence of insulin resistance, the lack of a well-defined cut point differentiating normal from abnormal, and the lack of data establishing whether modification of insulin resistance has an impact on outcomes.

d.)Fasting Proinsulin Concentration
This assay appears to have a high correlation with the prediction of diabetes and other related conditions.  This specific assay allows for the different molecules in proinsulin to be measured separately, and is named the 32,33 Split Proinsulin.  A study of this prohormone was a population-based-longitudinal cohort study conducted in England. Initially, .1,122 individuals were screening with a 75-g oral glucose tolerance test (OGTT). At the 4.5-year follow-up study, repeat OGTTs were performed on 937 of the cohort of 1,071 individuals who had been nondiabetic at baseline. The authors (15) cite the following results of their research:

A total of 26 people progressed to diabetes as determined by the OGTTs. The risk of progression was strongly related to the fasting glucose concentration (relative risk [RR] comparing top with bottom quartile 17.6 [95% CI 2.4–130.4]) and fasting 32,33 split proinsulin (RR 16.4 [2.2–121.9]), but less strongly to the fasting insulin (RR 4.41 [1.5–12.9]) or intact proinsulin (RR 5.2 [1.5–17.3]). In multivariate analyses, these associations were independent of age, sex, BMI, and baseline glucose tolerance category. Subjects in the top quartile for fasting glucose and total proinsulin with a family history of diabetes were a high-risk subgroup (incidence 65.8 per 1,000 person-years of follow-up [pyfu]); 30% of them progressed to diabetes at follow-up.

Proinsulin is a connecting peptide, and considered a prohormone to insulin.  It contains a connecting peptide or C-peptide, composed of 31 amino acids with an additional amino acid at either end linked to the alpha and beta chains. As is the case with other prohormones, the connecting peptide of proinsulin is cleaved off before insulin is released into the circulation Available: http://www.britannica.com/bcom/eb/article/6/0,5716,108526+2,00.html
Fasting 32,33 split proinsulin independently predicts the development of diabetes. This prediction was better than that observed for either the insulin or intact proinsulin concentrations. The combination of family history, fasting glucose, and total proinsulin identified a subgroup of individuals at high risk of progression who might benefit from targeted interventions.

Syndrome X

http://www.americanheart.org/presenter.jhtml?identifier=4756
Syndrome X has been observed in people who are insulin resistant. One such group is people with diabetes , who have a defect in insulin action and are unable to maintain a proper level of glucose in their blood. Another is people, primarily hypertensives (those with high blood pressure), who are nondiabetic and insulin resistant but compensate by secreting large amounts of insulin. This condition is known as hyperinsulinemia . A third group is heart attack survivors who, unlike hypertensives, have hyperinsulinemia without having abnormal glucose levels. The term "Syndrome X" also refers to a heart condition where chest pain, and electrocardiographic changes that suggest ischemic heart disease, are present, but where there are no angiographic findings of coronary disease. Some research has shown that people with cardiac Syndrome X also have lipid abnormalities, suggesting that the two syndromes may be the same.
Risk Factors include: central obesity (excessive fat tissue in the abdominal region), glucose intolerance hyperlipidemia - primarily high triglycerides and low HDL cholesterol and high blood pressure  Many scientists think that it is genetically based. The underlying cause is not fully understood. People with Syndrome X are at increased risk of coronary artery disease.
How is the metabolic syndrome diagnosed?
There are no well-accepted criteria for diagnosing the metabolic syndrome. The criteria proposed by the Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) are the most current and widely used.

According to the ATP III criteria, the metabolic syndrome is identified by the presence of three or more of these components:

  • Central obesity as measured by waist circumference:
    Men - Greater than 40 inches
    Women - Greater than 35 inches
  • Fasting blood triglycerides greater than or equal to 150 mg/dL
  • Blood HDL cholesterol:
    Men - Less than 40 mg/dL
    Women - Less than 50 mg/dL
  • Blood pressure greater than or equal to 130/85 mmHg
  • Fasting glucose greater than or equal to 110 mg/dL

The ATP III panel did not find evidence to recommend routine measurement of insulin resistance (e.g. increased fasting blood insulin), prothrombotic state or proinflammatory state.
AHA Recommendation
More studies are needed to understand the relationship between metabolic risk factors and the efficacy of drug therapy in people who have the metabolic syndrome.
To gain the most benefit from modifying multiple metabolic risk factors, the underlying insulin resistant state must become a target of therapy. The safest, most effective and preferred way to reduce insulin resistance in overweight and obese people is weight loss and increased physical activity.
Other steps for managing the metabolic syndrome are also important for patients and their doctors:
Routinely monitor body weight (especially the index for central obesity), blood glucose, lipoproteins and blood pressure.
Treat individual risk factors (hyperlipidemia, hypertension and high blood glucose) according to established guidelines.
Carefully choose anti-hypertensive drugs because different agents have different effects on insulin sensitivity.

Web Sites: Health Care Sites for Consumers
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Web Sites: Major Organizations
http://home.comcast.net/~creationsunltd/gdorgweb.html

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Pat Sonnenstuhl, ARNP, CNM

 Revised: 05/02/2008