Comparison of Waist-related Abdominal Obesity Measures: Marike Vuga Department of Epidemiology

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1 Comparison of Waist-related Abdominal Obesity Measures: A Simulation Study Marike Vuga Department of Epidemiology Obesity Journal Club January 21, 2010

2 Obesity and Health y Negative impact of obesity on health is well recognized in research and clinical practice. Abdominal obesity is y associated with the highest risk and worst outcome

3 Different Health Risks Based on Body Frame

4 Abdominal Obesity and Health Abdominal obesity is strongly associated with: Cardiovascular disease also associated with: also associated with: Diabetes Cancer Psoriasis Adverse pregnancy outcomes Earlier mortality in old age

5 Practical Abdominal Obesity Measures Two types: Waist-Related Measures Waist-Unrelated Measures

6 Practical Waist-Related Abdominal Obesity Measures Waist Circumference Waist to Hip Ratio (WHR) Waist to Height Ratio (WHtR) Waist to Thigh Ratio (WTR) Conicity Index (C) Abdominal Volume Index (AVI)

7 Abdominal Obesity Assessment The best practical way to assess abdominal The best practical way to assess abdominal obesity is still a topic of debate.

8 How to best measure abdominal obesity?

9 Waist Circumference Waist circumference measures the circumference around the waist

10 Waist to Hip Ratio Waist to Hip Ratio (WHR) is based on the ratio of the circumferences around the waist and the hip WHR=waist/hip

11 Waist to Height Ratio Waist to Height Ratio (WHtR) is based on the ratio of the circumferences around the waist and the height WHtR=waist/height

12 Waist to Thigh Ratio Waist to Thigh Ratio (WTR) is based on the ratio of the circumferences around the waist and the Thigh WTR=waist/thigh

13 Conicity Index Conicity Index (C) is based on the volume estimate of the body constructed between the shapes of a cylinder and a double cone. Conicity Index Waist circumfere nce (m) Weight (kg) Height (m)

14 Abdominal Volume Index Abdominal Volume Index (AVI) is based on the volume estimate of the waist hip body region as a truncated cone. AVI=[2(waist) (waist-hip) 2 ]/1000

15 Abdominal Obesity Measures: What Body Frame Measures Are Involved? Measure Waist Hip Thigh Height Weight Waist YES NO NO NO NO WHR YES YES NO NO NO WHtR YES NO NO YES NO WTR YES NO YES NO NO Conicity YES NO NO YES YES AVI YES YES NO NO NO

16 Abdominal Obesity Measures: Number of Body Frame Measures Measure Waist Hip Thigh Height Weight No Waist YES NO NO NO NO 1 WHR YES YES NO NO NO 2 WHtR YES NO NO YES NO 2 WTR YES NO YES NO NO 2 AVI YES YES NO NO NO 2 Conicity YES NO NO YES YES 3

17 Abdominal Obesity Measures: Decomposition Body Frame Measures Measure Waist x Hip y Height z Thigh t Weight w Factor * Op. Waist x WHR x 1/y * AVI 2.7 x (y 2-2xy) WHtR x 1/z * WTR x 1/t * Conicity x z 1/ w 9.17 *

18 Abdominal Obesity Measures Impact of Body Frame Measures To understand the behavior of these abdominal obesity measures with respect to body frame, 3D graphs were compiled.

19 Abdominal Obesity Measures 2D Graphs Functions of Waist Functions of Hip Functions of Height

20 Waist as a Function of Waist W aist Function Waist Circumference (cm)

21 AVI as a Function of Waist AVI W aist Function W aist Circumference (cm)

22 AVI as a Function of Hip AVI Hip Function Hip Circumference (cm)

23 WHR as a Function of Hip WHR Hip Function Hip Circumference (cm)

24 WHtR as a Function of Height W HtR Height Function Height (m)

25 Conicity as a Function of Height C Height Function Height (m)

26 Abdominal Obesity Measures 3D Graphs Waist by hip Waist by height Waist by weight

27 Waist Waist Hip

28 Waist to Hip Ratio Waist Hip

29 Abdominal Volume Index Waist Hip

30 Weight=70 kg (154 lbs) Height=1.8 m (5.9 ft) Conicity Index Waist Hip

31 Weight=40 kg (88 lbs) Height=1.5 m (4.9 ft) Conicity Index Waist Hip

32 Weight=100 kg (220 lbs) Height=1.7 m (5.6) Conicity Index Waist Hip

33 Weight=150 kg (330 lbs) Height=1.7 m (5.6 ft) Conicity Index Waist Hip

34 Weight=200 kg (440 lbs) Height=1.7 m (5.6 ft) Conicity Index Waist Hip

35 Abdominal Obesity Measures 3D Graphs Waist by hip Waist by height Waist by weight

36 Waist to Height Ratio Waist Height

37 Weight=40 kg (88 lbs) Conicity Index Waist Height

38 Weight=100 kg (220 lbs) Conicity Index Waist Height

39 Weight=150 kg (330 lbs) Conicity Index Waist Height

40 Weight=200 kg (440 lbs) Conicity Index Waist Height

41 Abdominal Obesity Measures 3D Graphs Waist by hip Waist by height Waist by weight

42 Height=1.7 m (5.6 ft) Conicity Index Waist Weight

43 Height=1.5 m (4.9 ft) Conicity Index Waist Weight

44 Height=1.9 m (6.2 ft) Conicity Index Waist Weight

45 Capture Circumference around the waist?

46 Waist Circumference by Gender

47 Waist Circumference by Gender

48 Waist Circumference by Body Size

49 Waist Circumference by Body Size

50 Waist Circumference Waist circumference cut off values Abdominal Obesity component within the Metabolic Syndrome classification: By gender By ethnic groups Grundy et al. Circulation. 2004;109:

51 Waist Circumference Waist circumference has some merit may not be ideal because it depends on body composition

52 WHR > 1 WHR < 1 Capture waist relative to hip circumference?

53 Skin fold Thickness

54 Waist to Hip Ratio by Body Size short tall

55 Waist to Hip Ratio Waist to hip ratio has some merit may not always estimate abdominal obesity well underestimate in heavy people who also have a large hip circumference overestimate in very thin people with straight body shape (and a low hip circumference)

56 Capture waist relative to height?

57 Waist to Height Ratio short tall

58 Waist to Height Ratio Waist to height ratio attempts to measure abdominal obesity relative to height. this seems to account in some way for body frame

59 Capture waist relative to Thigh?

60 Waist to Thigh Ratio

61 Waist to Thigh Ratio Waist to Thigh ratio attempts to measure abdominal obesity relative to Thigh circumference. Depends on body composition and overall pattern of body fat distributionib i

62 Capture body volume with respect to waist?

63 Conicity Index Conicity index is a promising abdominal obesity measure because it attempts to model the volume of the body with particular emphasis on the impact of the abdominal region

64 Capture abdominal/hip region volume?

65 Abdominal Volume Index Abdominal Volume Index is a promising abdominal obesity measure because it attempts to model the volume of the abdomen/hip area

66 Conculsion Although many abdominal obesity are used in research, only few involve relevant body frame aspects Among all measures, Waist to Height Ratio, Conicity Index, and AVI show the most promise

67 Outlook Next step: A method comparison study to compare these measures using real data. A thorough comparison of all these measures in terms of their predictability of relevant adverse health events using Receiver Operator Curves is warranted to guide policymaking and address the question which of these measures is most beneficial i lfor research and clinical i l practice.

68 Although we are still looking for the best measure, it is healthy to eat an apple

69 and look like an apple core

70 Ak Acknowledgement ld Kim Sutton-Tyrrell Ripu Jindal Baqiyyah Conway Emma Barinas-Mitchell Rodolfo Valdez Mark Woodward Anyone involved in abdominal obesity assessment

71 Thank you for your attention