Tracking the Accelerating Epidemic: Its Causes and Outcomes

1. AusDiab 2005The Australian Diabetes, Obesity and Lifestyle Study Tracking the Accelerating Epidemic: Its Causes and Outcomes

2. Baseline data from AusDiab 2000 • TheAusDiab survey carried out in 1999–2000 provides benchmark Australian prevalence data • 2000 findings, Australians  25 years old: – 7.4% had diabetes (doubled since 1981) – 16.3% had pre-diabetes (IFG/IGT*) – 59.6% were mildly overweight or obese – 28.8% had hypertension – 51.2% had total cholesterol ≥ 5.5 mmol/L, and 20.5% had elevated triglycerides (≥ 2.0 mmol/L) – 2.5% had proteinuria, 6.4% had haematuria and 1.1% had elevated serum creatinine * IFG ─ impaired fasting glucose; IGT ─ impaired glucose tolerance.

3. Aims of the five-year follow-up • Describe the natural history of: • Type 2 diabetes • Pre-diabetes (IFG/IGT*) • Associated cardiovascular disease, risk factors and complications • Identify risk factors associated with worsening glucose tolerance status and diabetic complications • Measure the progression of renal disease in diabetic and non-diabetic populations * IFG ─ impaired fasting glucose; IGT ─ impaired glucose tolerance.

4. Definitions for ‘prevalence’ and ‘incidence’ • 1999–2000 data:Prevalence – the proportion of people within a population who have a certain disease or condition at a particular time • 2004–05 data:Incidence – number of new cases of a disease or condition arising in a population over a period of time

5. Diabetes and pre-diabetes

6. Diabetes mellitus • Is a metabolic disorder with multiple causes characterised by chronically elevated blood glucose levels • Predisposes individuals to: • Cardiovascular disease – Visual loss • Amputations – Renal failure • Has many risk factors including obesity, hypertension and dyslipidaemia

7. Classification values for the oral glucose tolerance test Plasma glucose (mmol/L) Glucose tolerance World Health Organization. Department of noncommunicable disease surveillance, 1999

8. Diabetes in Australia:The last 20 years 1000 e) AusDiab d) Aust Bureau Statistics 800 c) Aust Bureau Statistics 600 Thousands b) Nat Heart Foundation 400 a) Busselton 200 0 ’98 ’86 ’96 ’80 ’82 ’84 ’88 ’90 ’92 ’94 ’00 Year

9. Age- and gender-specific prevalence (%) of diabetes Percentage Age group (years)

10. Age-specific prevalence (%) of IFG Percentage Age group (years) IFG ─ impaired fasting glucose

11. Age-specific prevalence (%) of IGT Percentage Age group (years) IGT ─ impaired glucose tolerance

12. Weighted prevalence (%) of associated conditions stratified by glucose tolerance status Glucose tolerance status Associated condition Diabetes IFG IGT Normal Hypertension* 69.3 43.5 50.1 21.1 Obesity (BMI  30 kg/m²) 44.4 30.1 31.5 15.9 LDL ( 3.5 mmol/L) 45.9 59.6 53.0 44.1 HDL ( 1.0 mmol/L) 23.1 16.8 11.6 10.6 Triglycerides ( 2.0 mmol/L) 42.9 31.4 31.1 16.0 * On treatment, or systolic pressure  140 mmHg, or diastolic pressure  90 mmHg IGT ─ impaired glucose tolerance; IFG ─ impaired fasting glucose.

13. Incidence of diabetes according to gender Incidence (% per year)

14. Incidence of diabetes according to baseline age Incidence (% per year) ≥ Baseline age (years)

15. Incidence of diabetes accordingto baseline glucose tolerance status Incidence (% per year) Baseline glucose tolerance NGT ─ normal glucose tolerance; IFG ─ impaired fasting glucose; IGT ─ impaired glucose tolerance.

16. Incidence of IGT and IFG Incidence (% per year) IGT ─ impaired glucose tolerance; IFG ─ impaired fasting glucose.

17. Incidence of diabetes according to baseline body mass index Incidence (% per year) Baseline BMI status Body mass index (BMI: weight/height2) was categorised into three groups: (i) normal: BMI < 25.0 kg/m2; (ii) overweight: 25.0─29.9 kg/m2; and (iii) obese: ≥ 30.0kg/m2.

18. Incidence of diabetes according to baseline waist circumference categories Incidence (% per year) Baseline waist circumference categories Waist circumference: (i) normal: < 94.0 cm for males, < 80.0 cm for females; (ii) overweight: 94.0─101.9 cm for males, 80.0─87.9 cm for females; (iii) obese: ≥ 102.0 cm for males, ≥ 88.0 cm for females.

19. Incidence of diabetes accordingto baseline physical activity Incidence (% per year) Baseline physical activities categories

20. Incidence of diabetes according to baseline hypertension status Incidence (% per year) Baseline hypertension status Hypertension (high blood pressure) was defined as having a blood pressure ≥ 140/90 mmHg and/or taking blood-pressure lowering medication.

21. Incidence of diabetes according to baseline dyslipidaemia status Incidence (% per year) Dyslipidaemia status at baseline Dyslipidaemia was defined as those with triglycerides ≥ 2.0 mmol/L or high-density lipoprotein cholesterol levels < 1.0 mmol/L.

22. Incidence of diabetes according to baseline metabolic syndrome status Incidence (% per year) Baseline metabolic syndrome status Metabolic syndrome was defined according to the definition by the International Diabetes Federation.

23. Diabetes  Key findings • Every year 0.8% of Australian adults develop diabetes • Every day in Australia approximately 275 adults develop diabetes • Those with pre-diabetes were 10–20 times more likely to develop diabetes than those with normal blood glucose levels • Obesity, hypertension, dyslipidaemia, physical inactivity and the metabolic syndrome each increased the risk for developing diabetes

24. Obesity

25. Body mass index classification Body mass index (kg/m2) Normal < 25.0 Overweight 25.0 – 29.9 Obese ≥ 30.0

26. Classification of abdominal obesity by waist circumference Waist circumference (cm) Males Females Normal < 94.0 < 80.0 Overweight 94.0 – 101.9 80.0 – 87.9 Obese ≥ 102.0≥ 88.0

27. Age-specific prevalence (%) of obesity*by BMI & waist circumference Age (years) Classification 25-34 35-44 45-54 55-64 65-74 75+ Total BMI Males 17.0 17.5 20.5 25.5 20.5 11.6 19.1 Females 12.2 19.4 26.0 31.9 29.7 14.9 21.8 Persons 14.7 18.4 23.2 28.7 25.5 13.5 20.5 Waist Males 13.6 24.6 27.4 35.8 41.2 36.8 26.6 Females 17.1 25.6 37.6 46.7 52.2 43.0 33.9 Persons 15.3 25.1 32.4 41.2 47.3 40.5 30.3 * BMI  30 kg/m²; Waist circumference: males  102 cm; females  88 cm

28. Mean weight change over five years according to baseline age Mean change in weight (kg) - 0.3 - 2.2 25 – 34 35–44 45–54 55–64 65–74 ≥ 75 Total Baseline age (years)

29. Mean body mass index change over five years according to baseline age 1.0 1.0 Mean change in BMI (kg/m2) - 0.2 25 – 34 35–44 45–54 55–64 65–74 ≥ 75 Total Baseline age (years)

30. Mean waist circumference change over five years according to baseline age 3.0 3.0 2.0 Mean change in waist circumference (cm) 25 – 34 35–44 45–54 55–64 65–74 ≥ 75 Total Baseline age (years)

31. Mean weight change over five years according to baseline body mass index status Mean weight change (kg) 1.0 Baseline BMI status

32. Mean waist circumference change over five years according to baseline BMI status 2.0 Mean waist circumference change (cm) Baseline BMI status

33. Incidence of obesity according to baseline body mass index status Incidence (% per year) 2.0 Baseline BMI status

34. Proportion of individuals classified by body mass index in 2004–05 according to baseline body mass index status BMI in 2004–05 BMI status at baseline Body mass index (BMI: weight/height2) was categorised into three groups: (i) normal: BMI < 25.0 kg/m2; (ii) overweight: 25.0─29.9 kg/m2; and (iii) obese: ≥ 30.0kg/m2.

35. Proportion of individuals classified by waist circumference in 2004–05 according to baseline waist circumference categories Waist circumference categories at baseline Waist circumference categories in 2004–05 Waist circumference: (i) normal: < 94.0 cm for males, < 80.0 cm for females; (ii) overweight: 94.0─101.9 cm for males, 80.0─87.9 cm for females; (iii) obese: ≥ 102.0 cm for males, ≥ 88.0 cm for females.

36. Obesity  Key findings • People aged < 65 years showed an average weight increase of 1.8 kg over five years • People aged ≥ 65 years showed a loss in weight of 0.8 kg over the same period • Waist circumference  average gain over five years was 2.1 cm; greater in females than males • Younger people gained more weight and had a greater increase in waist circumference than did older people • Twice as many overweight people became obese as reverted to normal

37. Hypertension

38. Role of hypertension • High blood pressure is a risk factor for cardiovascular and renal disease • For individuals with diabetes, high blood pressure is a risk factor for microvascular complications as well as cardiovascular disease • The baseline study found that 28.8% of adults ≥ 25 years of age were classified as hypertensive (BP ≥ 140/90 mmHg or taking BP lowering medication)

39. Classification of blood pressure Systolic blood Diastolic blood Blood-pressure pressure (mmHg) pressure (mmHg) lowering medication Normal < 140 and < 90 and No Hypertension ≥ 140or≥ 90or Yes Guidelines Subcommittee. J Hypertens 1999; 17: 15183.

40. Prevalence (%) of adequate blood pressure* control among people on anti-hypertensive therapy Age (years) 25–34 35–44 45–54 55–64 65–74 75+ Total Males 55.8 45.3 37.4 28.7 20.1 34.3 Females 75.5 75.9 59.2 47.6 43.2 33.7 46.4 Persons 75.5 66.4 52.6 42.6 37.3 29.3 41.4 *Systolic pressure  140 mmHg, and a diastolic pressure  90 mmHg, and on anti-hypertensive medication

41. Proportion of individuals classified with hypertension in 200405 according to baseline hypertension Hypertension status in 2004–05 Hypertension status at baseline

42. Incidence of hypertension according to baseline age Incidence (% per year) ≥ Baseline age (years)

43. Incidence of hypertension according to baseline glucose tolerance status Incidence (% per year) Baseline glucose tolerance status NGT ─ normal glucose tolerance; IFG ─ impaired fasting glucose; IGT ─ impaired glucose tolerance; DM – diabetes mellitus

44. Incidence of hypertension according to baseline body mass index status Incidence (% per year) Baseline BMI status BMI: Body mass index; where (i) normal was a BMI of < 25.0 kg/m2; (ii) overweight was a BMI of 25.0─29.9 kg/m2; and (iii) obese was a BMI of ≥ 30.0kg/m2.

45. Incidence of hypertension according to baseline smoking status Incidence (% per year) Baseline smoking status

46. Hypertension  Key findings • 3.0% of adults develop hypertension every year • The risk increases with age from 1.0% per year at 2534 years of age to 8.4% per year at 6574 years of age • Those at greatest risk are people: • With diabetes and pre-diabetes (females higher risk than males) • Who are overweight or obese (females higher risk than males) • Who smoke (males higher risk than females)

47. Metabolic syndrome

48. Significance of the metabolic syndrome • The metabolic syndrome is characterised by central or abdominal obesity, and a clustering of cardiovascular risk factors, such as: • Abnormal glucose tolerance • Raised triglycerides • Decreased HDL-cholesterol • Hypertension • Hyperinsulinaemia (with underlying insulin resistance) • The metabolic syndrome confers a higher risk of diabetes and cardiovascular disease

49. Threshold Classification of the metabolic syndrome Component Alberti KG et al.Lancet 2005; 366: 105962.

50. Incidence of the metabolic syndrome according to gender 3.0 Incidence (% per year)