Bone Health and Osteoporosis: A Report of the Surgeon General, 2004
Osteoporosis—A Report by the Surgeon General, 2004
Osteoporosis Defined
World Health Organization (WHO) Definition
Skeletal disorder characterized by compromised bone strength, leading to increased fracture risk.
Two important factors to consider:
Peak Bone Mass
Rate of Bone Loss
Classification of Osteoporosis
Primary Osteoporosis (non-reversible without intervention)
Involutional Type I
Affects women, primarily during menopause.
Associated with crush fractures, high bone loss, and turnover rates.
Primarily impacts trabecular bone in the axial skeleton.
Type II
Affects men and women over age 70.
Involves crush fractures, especially of the hip and other bones.
Loss of both trabecular and cortical bone.
Secondary Osteoporosis
Resulting from endocrine, gastrointestinal, or marrow disorders.
Partially reversible with treatment.
Osteoporosis as a Public Health Threat
Approximately 44 million Americans affected.
Demographics: 68% female.
Statistics: 10 million diagnosed with osteoporosis, 34 million with osteopenia.
Lifetime risk of osteoporosis-related fractures:
1 in 2 females
1 in 4 males
Annual fractures related to osteoporosis:
300,000 hip fractures
700,000 vertebral fractures
250,000 wrist fractures
300,000 fractures at other sites
Total annual cost due to osteoporosis and fractures: approximately $18 billion.
Impact of Hip Fracture on Health
Consequences:
50% of those with hip fractures remain unable to walk unassisted.
25% are confined to nursing homes afterward.
Death statistics: significant mortality within 6 months post-fracture.
Social and psychological implications due to mobility loss.
NOF Recommendations for Bone Mineral Density (BMD) Testing
Testing Recommendations:
All women aged 65 and above, regardless of risk factors.
Younger postmenopausal women with one or more additional risk factors (excluding being white, postmenopausal, female).
Postmenopausal women who have sustained a fracture.
Risk Factors for Osteoporosis
Intrinsic Factors:
Low bone mass
Female gender
Age
Estrogen or sex hormone deficiency
Early menopause (age < 45)
Surgical menopause
Low testosterone in men
Conditions like amenorrhea and anorexia nervosa
Race: Caucasian or Asian descent
Low weight & Body Mass Index (BMI): weight < 127 lbs
Family history of fractures in first-degree relatives
Smoking history
History of prior fractures, especially after age 45
Low physical activity levels
Nutritional deficiencies: calcium, vitamin D, total calories, and protein intake.
Medication use and certain chronic medical conditions.
Fracture Risk Factors
Key indicators of fracture risk include:
Personal history of fractures
Reduced gait speed
Decreased quadriceps strength
Impaired cognitive function and vision
Environmental risks and hazards
History of fractures with falls
Individual height and hip axis length, femur length.
Clinical Presentation of Osteoporosis
Spinal Osteoporosis:
Patients may experience acute or intermittent back pain, often triggered by normal activities.
Chronic back pain may also develop over time.
Common Symptoms:
Loss of height
Spinal deformity (kyphosis)
Common fracture sites include:
Spine
Hip
Many fractures may be asymptomatic initially.
Diagnostic Approach to Osteoporosis
Diagnosing Osteoporosis:
X-ray evaluation of painful sites to detect crush fractures or other bone loss.
Dual-energy X-ray absorptiometry (DXA) used to ascertain severity of bone loss; this method is the gold standard for diagnosis.
Laboratory chemistries for determining secondary causes of bone loss.
Monitoring “bone markers” to evaluate bone turnover rates.
DXA Scan Results
DXA Results Summary:
Total BMD analysis consisting of the following metrics for different body regions (Left Arm, Right Arm, Trunk, Left Leg, Right Leg, Total):
Results include Bone Mineral Content (BMC), Fat Mass, Lean Mass, Lean+BMC, Total Mass, and % Fat percentages.
Region
BMC (g)
Fat (g)
Lean (g)
Lean+BMC (g)
Total Mass (g)
% Fat
L Arm
146.03
549.2
2067.0
2213.0
2762.2
19.9
R Arm
161.21
498.7
2394.4
2555.6
3054.3
16.3
Trunk
646.57
4665.7
21880.8
22527.4
27193.1
17.2
L Leg
402.11
1665.7
6728.9
7131.0
8796.7
18.9
R Leg
416.10
1635.8
7027.8
7443.9
9079.7
18.0
Subtotal
1772.03
9015.1
40098.8
41870.8
50885.9
17.7
Head
542.54
797.5
2747.3
3289.9
4087.3
19.5
Total
2314.57
9812.6
42846.1
45160.7
54973.3
17.8
Diagnosing Osteoporosis via DXA T-score
T-score Interpretations:
Normal: T-score not less than -1
Osteopenia: T-score between -1 and -2.5
Osteoporosis: T-score lower than -2.5
Severe Osteoporosis: T-score lower than -2.5 with additional fragility fractures present.
WHO Categories of Osteoporosis
Normal: T-score > -1
Osteopenia: T-score between -1 and -2.5
Osteoporosis: T-score < -2.5
Bone Mass Across the Lifespan
During adolescence, approximately 40% of peak bone mass is formed.
By the age of 20, 90-95% of peak bone mass is achieved.
Around the time of menopause (~5 years), annual bone loss rates are approximately 1-2% for cortical bone and 2-3% for trabecular bone.
BMD and Fracture Risk
Each standard deviation (SD) decrease in neck BMD is associated with an over 2.5 times increase in the age-adjusted risk of hip fracture, equivalent to a T-score of 1.
T-score vs. Z-score
T-score: Compares individual's score to a reference group.
Z-score: Compares individual's score to similar peers/age group.
Implications of using T-score and Z-score may differ among various populations.
NOF Steps to Slow Disease Progression
Adhere to a diet rich in calcium and vitamin D.
Engage in weight-bearing exercise regularly.
Avoid smoking and limit alcohol intake.
Schedule regular health care assessments.
Undergo periodic BMD testing and consider medication as necessary.
Three-Legged Stool Concept for Bone Health
Adequate nutrition (calcium and vitamin D).
Regular physical activity.
Lifestyle modifications (avoid smoking, manage alcohol consumption).
Critical Strategies for Bone Health
Deposit in the “Bone Bank”: Build bone mass during the first 25-30 years of life.
Minimize Withdrawals: Limit bone loss after peak bone mass is reached.
Treatment Options for Primary Osteoporosis
Supplementation:
Calcium (1200-1500 mg daily based on age and health status)
Vitamin D (400-800 IU daily)
Hormonal Treatments:
Estrogen Therapy (ET)/Hormone Replacement Therapy (HRT)
Selective Estrogen Receptor Modulators (SERMs), e.g., Raloxifene (Evista), Tamoxifen
Anti-Resorptive Agents:
Bisphosphonates such as Etidronate, Alendronate (Fosamax), Risedronate
Calcitonin (nasal administration) - emerging evidence supports effectiveness
Parathyroid Hormone (PTH) therapy (Teriparatide)
Nutrition Focus: Emphasizing adequate calories, protein-rich diet, exercise as an adjunct in treatment.
Exercise and Fracture Prevention
Factors influencing fracture risk:
Bone Dependent Factors: Bone mass, BMD, cortical and trabecular tissue integrity, osteoblast and osteoclast activity.
Bone Independent Factors: Increasing general fitness and strength, improved balance.
Exercise & Bone Remodeling
Key physical factors leading to positive outcomes in bone:
Increased compression and tension contribute to improved bone strength through fluid shifts that lead to increased bone deposition and remodeling.
Age-Specific Exercise Recommendations
Childhood and Adolescence: Focused on building a strong base of bone mass during critical periods, especially around peak height velocity.
Young Adults: Prioritize maintaining bone mass until peak bone mass is achieved.
Middle Age and Older Adults: Implementwise physical activity regimens to prevent or slow bone loss, particularly around menopause and into older age.
Jump Training Outcomes
Evidence from prospective controlled studies indicates that BMD can increase on average by 1.8-3% at sites that endure loading from exercises. The efficacy is intensity-dependent.
Bone Density and Influence of Weight Loss, Estrogen, and Bone Loss
Findings: Studies illustrate impacts of weight stability or weight loss on composite BMD readings across lumbar spine and hip. Over certain treatments and trials:
Raloxifene, HRT outcomes differed significantly per study results, with implications on age and overall health.
Summary Insights
Prospective controlled studies illustrate high-impact interventions yield BMD increases ranging from 1-3% which emphasizes that incremental improvements can lead to significant long-term bone health benefits.
Open questions pertain to optimal exercise regimens, considerations for weight loss in elderly populations, and general study of best practices for managing osteoporosis.