MSc in Diabetes A population approach

1
MSc in DiabetesA population approach
UniS
Impaired glucose tolerance and undiagnosed
diabetes
Ross Lawrenson Postgraduate Medical
School University of Surrey
2
Metabolic syndrome

• Impaired glucose tolerance
• Undiagnosed Type 2 diabetes

3
Theories on the aetiology of Type 2 diabetes

• Barker hypothesis
• Reaven Syndrome
• Thrifty genotype

4
Barker hypothesis

• The thrifty phenotype

5
Odds ratio of NIDDM and IGT related to birth
weight
Odds Ratio
Birth Weight in pounds
6
Barker hypothesis

• Malnutrition in the prenatal and early infant
  years. (Hales and Barker)
• Beta cells increase of 130 times between 12 th
  intra-uterine week and 5 th post natal month.
• Malnutrition.
• Obesity in later life.

7
Reaven syndrome

• First described by Himsworth in 1936
• Described in New Zealand by Ian Prior in 1966 in
  Maori (obesity, hypertension diabetes and gout)
• Syndrome X sometimes called Reaven syndrome after
  Gerry Reaven

8
Relationship between glucose uptake and fasting
plasma glucose
Reaven G. Diabetes 1988
9
Reaven syndrome

• Reaven syndrome or Syndrome X
• Resistance to insulin-stimulated glucose uptake
• Hyperinsulinaemia or glucose intolerance
• Hypertension
• Decreased HDL
• Increased VLDL
• Central obesity

10
Thrifty genotype

• Thrifty genotype
• Ability to lay down fat
• Survive times of hardship
• Alternative metabolic pathway in high protein diet

11
Age adjusted prevalence of NIDDM and IGT in
adults aged over 20 years
Simmons D. The Coventry Diabetes Study. Quarterly
Journal of Medicine. 1991 81 1021-1030
12
Prevalence of undiagnosed NIDDM with age in New
Zealand adults aged over 20 years. The overall
crude rate was 56/3896 (1.4).
13
Prevalence of undiagnosed NIDDM per 1000 people
screened by BMI.
14
Mean BMI of men and women by ethnic origin.
15
Variables associated with the presence of
undiagnosed diabetes in people 40 years.
16
Significant factors associated with undiagnosed
diabetes in Europeans over the age of 40 years.
95 Confidence interval
Variable
Adjusted OR
Age
1.07
1.04 - 1.10
BMI
1.13
1.06 - 1.21
Family history
2.34
1.16 - 4.71
17
Study using the General Practice Research
Database - characteristics of subjects
Type 1 Type 2 Mean age in
1992 33.4 63.6 Mean age at diagnosis (yrs)
18.0 56.7 Mean duration to 1992 (yrs)
16.2 7.1 Mean period of follow-up
(yrs) 5.3 5.1
Total of 5528 type 1 and 25707 type 2 patients
18
Impaired glucose tolerance

• This group are asymptomatic and do not have
  diabetes
• Do not suffer the microvascular complications
• The diagnosis is important because
• High rate of macrovascular disease
• A number will eventually become diabetic
• Secondary prevention in this group may reduce
  morbidity and mortality

19
Prevalence
20
Progression to diabetes
21
Impaired glucose tolerance

• After 10 years between 15 and 45 will have
  diabetes
• After 10 years about 1/3 will be normal
• If OGTT is repeated within 3 months approximately
  50 will have a normal GTT
• Tukitonga showed that those with IGT in Niue who
  progressed to diabetes were more likely to be
  sedentary whilst those who were active were more
  likely to return to normal
• Tuomilheto J, Lindstrom J, Eriksson JG, Valle TT,
  Hamalainen H, Ilanne-Parikka P et al. Prevention
  of Type 2 diabetes mellitus by changes in
  lifestyle among subjects with impaired glucose
  tolerance. New England Journal of Medicine 2001
  344(18) 1343-9

22
Summary

• Type 2 diabetes is increasing
• Intervention strategies are needed to reduce
  incidence
• Identifying undiagnosed patients with type 2
  diabetes may reduce onset of complications
• Identifying and treating IGT has proved worthwhile