Huyen bai giang loang xuong

Osteoporosis research:
Current Concepts and Research
Dr Tuan V. Nguyen
Associate Professor
Bone and Mineral Research Program
Garvan Institute of Medical Research
Sydney, Australia

Garvan Institute of Medical Research


NộI dung
ã định nghĩa và các khái
niệm
ã Các yếu tố nguy cơ
ã Chẩn đoán và đo mật độ
xơng
ã điều trị
ã Nhng ®iĨm míi?
Garvan Institute of Medical Research


Normal vs Osteoporosis

Garvan Institute of Medical Research


Osteoporosis
Osteoporosis: LoÃng xơng (LX) là một
bệnh chuyển hoá xơng, đợc đặc
trng bởi khối lợng xơng thấp tới

mức làm xơng giòn và dẫn tới
nguy cơ gÃy xơng
(Consensus Development Conference, 1991)

Garvan Institute of Medical Research


Thay đổi quan đIểm

LoÃng xơng: Yếu tố nguy cơ
NgÃy xơng: HËu qua

Garvan Institute of Medical Research


G·y x¬ng

Garvan Institute of Medical Research


Tû lƯ g·y x¬ng theo ti

Ty le mac moi/100,000 dan

500

Nu

400

Nam

300
200
100
0
0-4

5-14

1524

2534

3544

4554

5564

6574

7584

85+

Garvan Institute of Medical Research


ã định nghĩa và các khía

niệm
ã Các yếu tố nguy cơ
ã Chẩn đoán và đo mật
độ xơng
ã điều trị
ã Nhng ®iĨm míi?
Garvan Institute of Medical Research


Ngà và nguy cơ ngÃy xơng
Yếu cơ
tứ đầu
T thế
không ổn
định

NgÃ

NgÃy xơng
đùi

ã Interaction between BMD and fall-related
factors in the prediction of hip fracture
Garvan Institute of Medical Research


Postural Sway Test

Garvan Institute of Medical Research

Risk Factors
Genetics

Race, Sex, Familial prevalence

Hormones

Menopause, Oophorectomy, Body composition

Nutrition

Low calcium intake, High caffeine intake,
High sodium intake, High animal protein intake

Lifestyles

Cigarette use, High alcoholic intake,
Low level of physical activity

Drug

Heparin, Anticonculsants, Immunosuppressants
Chemotherapy, Corticosteroids,
Thyroid hormone
Garvan Institute of Medical Research


Risk Factors for Low Bone Mass
Smoker

Age (per 5 years)
Maternal history of fx
Steroid use
Caffeine intake
Activity score
Age at menopause
Milk intake
Ever pregnant
Surgical menopause
Waist/hip ratio
Weight
Grip strength
Height
Thiazide use
Oestrogen use

Garvan Institute of Medical Research


• Definition and concepts
• Risk factors
• Diagnosis and bone mineral
density
• Treatment
• What is new?
• Research directions
Garvan Institute of Medical Research


Bone Mineral Density

• Measured by dual-energy X-ray absorptiometry
(DXA)
• Bone mineral density, BMD (g/cm2) = BMC / Area
• Bone mineral content, BMC (g)
• Region of interest: Area (cm2)
– Femoral neck
– Lumbar spine
– Total body
Garvan Institute of Medical Research


Femoral Neck

Garvan Institute of Medical Research


Vertebrae

Garvan Institute of Medical Research


Areal Density and Volumetric Density

Garvan Institute of Medical Research


BMD and Age

Peak BMD

Bone
Mineral
Density

Menopause
Osteopenia
Puberty

Osteoporosis

Age

Garvan Institute of Medical Research


BMD T-score
• T-score: the number of standard deviations (SD)
from the young normal mean
• Young normal mean: mean BMD of women aged
between 18 and 30 yrs
• SD: standard deviation of BMD in women aged
between 18 and 30 yrs

Garvan Institute of Medical Research


BMD T-score
• T-scores = (BMD of an individual – YN) / SD
• Example:
– Mrs Trang, 70 years old, has a femoral neck BMD of 0.68

g/cm2.
– The mean BMD of Vietnamese women aged 18-30 yrs is
1.00 g/cm2
– The SD of BMD in Vietnamese women aged 18-30 yrs is
0.12 g/cm2
– Mrs Trang’s T-score is:
T = (0.68 – 1.00) / 0.12 = -2.66
Garvan Institute of Medical Research


BMD Z-score
• Z-score: the number of SDs from the mean BMD
of age-matched individuals
• Z-score = (BMD of an individual – BMD of all
individuals in her age) / SD

Garvan Institute of Medical Research


BMD Z-score
• Example:
– Mrs Trang, 70 years old, has a femoral neck BMD
of 0.68 g/cm2.
– The mean BMD of Vietnamese women 70 yrs is
0.80 g/cm2
– The SD of BMD in Vietnamese women 70 yrs is
0.10 g/cm2
– Mrs Trang’s T-score is:
T = (0.68 – 0.80) / 0.10 = -1.20
Garvan Institute of Medical Research

Diagnosis of Osteoporosis
Osteoporosis:
Osteopenia:

T-score < -2.5
-2.5 < T-scores < -1

Normal: T-scores > -1

Garvan Institute of Medical Research


BMD and Fracture Risk
High risk

Low risk

Garvan Institute of Medical Research


Predictive Value of BMD
1287women

Osteoprosis
345 (27%)

Fx = 137
(40%)

No Fx =
208 (60%)

42%

Not Osteop.
942 (73%)

Fx = 191
(20%)

No Fx = 751
(80%)

Garvan Institute of Medical Research