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HKU finds overweight and obesity significantly increase the risk of

spinal disc degeneration and low back pain in adults

Professor Kenneth CHEUNG Man-cheeDr. Dino Samartzis

Department of Orthopaedics and TraumatologyThe University of Hong Kong Li Ka Shing Faculty of Medicine

Guest speaker: Dr. Robin MelleckerInstitute of Human Performance, The University of Hong Kong

26th February, 2012

Intervertebral Disc

• Provides structure and function of the spinal column

• Cushion and shock absorber

• Indirectly protects neural elements

Intervertebral Disc

Spinal Cord

VertebralBody

Nerve Root

2

Normal SpineDisc

Degeneration Low Back Pain

Samartzis D, et al. World Forum for Spine Research, Montreal, 2010de Schepper EI, et al. SPINE. 35: 531-6, 2010

Luoma K, et al. SPINE. 25: 487-92, 2000

Disc Degeneration Leads to the Development of Low Back Pain

Low Back PainGlobal Burden of Disease

• 2nd most common condition seeking clinical consult

• Decreases daily function & productivity

• Diminishes the quality of life

• Lost wages

• Increases health-care costs

• Psychological distress

• Low back surgery is the most common surgery

Shen F, Samartzis, D, Andersson GBJ. J Am Acad Orthop Surg. 14: 477-87, 2006Wong WS and Fielding R. J Pain. 12:236-245, 2011

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Low Back Pain ‐ Rehabilitation

• Physiotherapy

– Strength

– Endurance

– Physical fitness

• Occupational therapy

– Work safety

– Work related training

2012/2/26

✔

✖

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Current treatment for severe back pain from disc degeneration

Lumbar Disc Degeneration

Age

Bio-mechanics

Genetics

Overweight &

Obesity

Major Causes of Lumbar Disc Degeneration

?

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• Population-based study (since 2001)

• Currently 3,500 Southern Chinese subjects

• Largest cohort in the world assessed with MRI

Hong Kong Degenerative Disc Disease Cohort Study

Assessment of Disc Degeneration(DDD Score)

Schneiderman G et al. Spine 1987;12:276-81

Radiographic Criteria for Disc Degeneration

Grade Description

0 (Normal) No signal changes

1 Slight decrease in signal intensity of the nucleus pulposus

2 Hypointense nucleus pulposus with normal disc height

3 Hypointense nucleus pulposus with disc space narrowing

5 lumbar discs scored for disc degenerationand “summated” for DDD Score (potential score range: 0 to 15)

End-Stage

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Examples of Degenerative Disc Disease (DDD) Score

Assessment of Disc Degeneration on MRI

Actual Sum DDD Score 0 (Normal) 2 (Mild-Medium) 6 (Moderate-Severe)

Category Normal Mild-Medium Moderate-Severe

DDD Score Range 1 1 to 4 >5

1

1.4

1.8

2.2

3.4

1

2

3

4

5

6

0 1-2 3-4 5-6 7 or >

Low

Bac

k P

ain

Od

ds

Rat

io (

95%

CI)

Degree of Disc Degeneration (DDD score)

* Model adjusted for age, sex, marrow changes, and workload (N=2,599)

Normal Mild Medium Moderate Severe

7

1

1.4

1.8

2.2

3.4

1

2

3

4

5

6

0 1-2 3-4 5-6 7 or >

Low

Bac

k P

ain

Od

ds

Rat

io (

95%

CI)

Degree of Disc Degeneration (DDD Score)

* Model adjusted for age, sex, marrow changes, and workload (N=2,599)

Increasing disc degeneration severity, increases risk of low back pain in Hong Kong adults !

Normal Mild Medium Moderate Severe

Hong Kong Degenerative Disc Disease Cohort Study

3,500 Subjects (10 to 80 years old)

2,599 Included Subjects(21 to 63 years old)

No Disc Degeneration Disc Degeneration

Research Methodology

Body Mass IndexUnderweight (<18.5 kg/m2)

Normal Weight (18.5-23.0 kg/m2)

Overweight (23.0-27.5 kg/m2)

Obese ( > 27.5 kg/m2)

Group 1 Group 2

* After taking into account the exclusion criteria, a total of 2,599 individuals were assessed.

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Male30 years old1.70 meters

Body Mass Index (BMI)BMI = Weight (kg) / height (m2)

50 kg – Underweight60 kg – Normal70 kg – Overweight80 kg – Obesity

45 kg – Underweight50 kg – Normal65 kg – Overweight75 kg – Obesity

Female30 years old1.60 meters

Examples Examples

Part II

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HKU research findings

Prevalence of Disc Degeneration

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Prevalence of Disc Degeneration

No Disc Degeneration,

27%

Disc Degeneration,

73%

Disc degeneration more prevalent in older age.

* Results are based on MRI of participants

40.5

69.8

81.6

90.7100

0

20

40

60

80

100

21-30 31-40 41-50 51-60 >60D

isc

Deg

ener

atio

n (

Per

cen

tage

)

Age Categories

21.7

23.3

20

21

22

23

24

Without Disc Degeneration With Disc Degeneration

Mea

n B

ody

Mas

s In

dex

(k

g/m

2 ) p<0.001

Significantly higher body mass indexwith disc degeneration !

11

1.4

2.5

3.3

3.8

0

1

2

3

4

Underweight Normal Overweight Obese

Mea

n D

DD

Sco

re (

Lu

mb

ar S

pin

e)

Body Mass Index Categories

p<0.001

DDD=Degenerative Disc Disease

The heavier, the more severity of disc degeneration !

p<0.001

p=0.092

0.2

0.3

0.4

0.5

0

0.2

0.4

0.6

Underweight Normal Overweight Obese

Mea

n N

um

ber

of

Dis

cs w

ith

En

d-S

tage

Dis

c D

egen

erat

ion

Body Mass Index Categories

p=0.001

p=0.012

The heavier, the more likely to suffer from “end-stage” disc degeneration !

p=0.322

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Increasing BMI, Increases Likelihood of Disc Degeneration

Overweight30% increased risk for

disc degeneration

* Model adjusted for age, previous lumbar injury, Schmorl’s nodes & marrow changes.

Increasing BMI, Increases Likelihood of Disc Degeneration

Obesity 79% increased risk for

disc degeneration

* Model adjusted for age, previous lumbar injury, Schmorl’s nodes & marrow changes.

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Increasing BMI, Increases Likelihood of Disc Degeneration Severity

Obesity 72% increased risk for

“end-stage” disc degeneration

* Model adjusted for age, sex, workload, previous lumbar injury, Schmorl’s nodes & marrow changes.

42 y/o female underweight (18.3 kg/m2)

no disc degeneration

43 y/o femalenormal weight

(21 kg/m2) no disc degeneration

45 y/o female overweight (26.6 kg/m2)

disc degeneration L2/L3 with disc space

narrowing,L3/L4, and L5/S1

46 y/o maleobese

(31.0 kg/m2)disc degeneration

L2 to S1

Case Examples

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Summary of Research Findings

• Overweight/obesity significantly more pronounced with – Presence

– Extent

– Severity

of disc degeneration

Largest study to assess BMI & disc degeneration

• Obesity DOUBLES the risk of disc degeneration

Part III

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Adult Overweight and Obesity in Hong Kong

Information obtained from The Hong Kong Department of Health Behavioral Health Risk Factor Survey for ages 18‐64. http://www.chp.gov.hk/en/data/4/10/280/427.html

Overweight Obese0

5

10

15

20

25

30MaleFemaleOverall20.8

15.918.2

27.5

15.5

21.0

Per

cen

tag

e

Female FemaleOverall OverallMale Male

Physical Activity

Information obtained from WHO http://www.who.int/dietphysicalactivity/factsheet_adults/en/index.html

Information obtained from The Hong Kong Department of Health http://www.chp.gov.hk/en/data/4/10/280/427.html

36%

64%

Meet World Health Organization Recommendations

No

Yes

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Weight Loss & Maintenance

• Start Slow and Simple– Combine diet and physical activity

– Low intensity (walking)

• Successful strategies (NWCR)*– Dietary changes (low-fat, high complex carbohydrate)

– Daily breakfast

– Frequently monitor weight

– Participate in high level of physical activity

*Information obtained from the National Weight Control Registry (NWCR) http://xnet.kp.org/permanentejournal/

sum03/registry.html

Part IV

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Lumbar Disc Degeneration

Age

Bio-mechanics

Genetics

Overweight

&

Obesity

Major Causes of Lumbar Disc Degeneration

Lumbar Disc Degeneration

Age

Bio-mechanics

Genetics

Overweight

&

Obesity

Major Causes of Lumbar Disc Degeneration

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Public Health Concern !

Obesity and overweight - negative health impacts

• Diabetes

• Cardiovascular Disease

• DISC DEGENERATION & LOW BACK PAIN

What is bad for the heart, is also bad for the back !

Increase Awareness

• Overweight/obesity in adults– Leads to greater severity of disc degeneration

– Increase risk of low back pain

• Preventive measures– Avoid being overweight/obese

Public Health Concern !