Lumbar Epidemiology

Question 1

Prevalence

Answer 1

• Prevalence: percentage of known population who have a condition of interest at any point in time
• Point prevalence: percentage who have the condition at the specific point in time
• One-month, 1-year prevalence: percentage with the condition during that time frame
• Lifetime prevalence: percentage who have had the condition sometime in their lifetime

Question 2

Incidence

Answer 2

• Incidence: the occurrence, rate, frequency from a point forward. Percentage of a known population who develop new problems within a given time frame from a defined point. Looking to the future.

Question 3

LBP Prevalence

Answer 3

Taylor & Curran 1985.

• Second most common pain in U.S. after headache (HA)
• 56% with at least 1 day of LBP in previous year
• 34% reported LBP 6 days or more
• 14% with LBP > 40 days

Papageorgiou 1995

• British study found 1-month prevalence of 39%
• Life-time prevalence of 58%

Walsh 1992, Mason 1994

• 1-year prevalence of 36% - 37%
• 6%-7% adults have LBP constantly

Croft 1997

• 60% -80% get back pain sometime in their lives
• Most attacks settle rapidly, recurrences are common
• 35% to 40% report back pain > 24 hours each month
• Strongest predictor of LBP was a history of previous LBP.

Question 4

Low Back Pain

Answer 4

• Back pain has been a common symptom (back pain is a symptom, not a disease or a diagnosis) since early history.
• There does not appear to be a change in the prevalence or incidence of LBP over the past 40 years.
• Disability due to back pain has increased over the past several decades, believed to be due to social / political factors.
• Cost of low back pain is increasing annually.
• Most common diagnosis given is non-specific lower back pain .
• In the majority of patients, the pathology is not truly understood. An accurate diagnosis cannot be reached.
• In most cases, imaging is not helpful, and can be misleading.
• Concept of dysfunction rather than pathology is the growing trend for management outside of surgical intervention.

Question 5

Concept of dysfunction

Answer 5

• Dysfunction is based on an imbalance between physical stresses and individual vulnerabilities, and their interaction over time (Waddell 2004).

Question 6

Genetics

Answer 6

• Disc degeneration and certain aspects of LBP can be attributed to genetic factors or a familial element.

Question 7

Gender

Answer 7

• Limited effect
• Sciatica more common in men (Heliovaara 1987)
• Women can have LBP during pregnancy

Question 8

Age

Answer 8

• Results for the effect of age vary across studies.
• Most population studies show the prevalence of LBP to increase with age up to 50 years of age, then levels or falls off slightly.
• 1-year prevalence aged 68 to 80 years and 81 to 100 years was at 50%. Thoracic pain prevalence was slightly higher in women than men.
• Self-reported disability increases up to 40 - 49 years of age, then levels.

Question 9

Physical Fitness

Answer 9

• The level of cardiovascular fitness is not a risk factor for future back pain (Andersson 1997, Nachemson & Vingard 2000)
• Though not substantiated by RCT’s, the common clinical impression is that physically fit patients recover more rapidly and are less likely to develop chronic pain / disability.

Question 10

Smoking

Answer 10

• Association between back pain and smoking is weak (Leboeuf-Yde 1999, Goldberg et al 2000)
• Alcohol consumption has not been shown to be a risk factor (Leboeuf-Yde 1999)

Question 11

Social class and LBP

Answer 11

Walsh 1992

For men, back pain and disability > Classifications IV and V (65% versus 51% in I and II)

For women, no trends found

• I: Professional
• II: Self-employed, teachers
• III: Skilled occupations, non-manual
• IV: Partly skilled, transport work
• V: Unskilled laborers

Lower social class is a weak risk factor for back pain, stronger association for resulting disability.

Question 12

Education and LBP

Answer 12

Association between lower level of education and higher level of back pain.

People with less than 13 years of schooling have more disability.

Higher education level is associated with better rehabilitation outcome.

Question 13

Emotional distress

Answer 13

Emotional distress appears to be a risk factor for development of back pain in symptom free individuals (incidence).

Burton 1996, Linton 2000, Manninen et al 1995

Question 14

Environmental Risk Factors

Answer 14

• 60% to 80% of adults experience LBP at some point. Most common reason for time off work.
• Manual materials handling, lifting, twisting, and vibration are associated with increased reports of back injury.
• Effect of cumulative risk exposure has not been discerned.
• Strong association between sitting and LBP.
• Physical demands of work plays only a minor role in development of disc degeneration.

Question 15

Psychosocial factors

Answer 15

Lack of job satisfaction (strong evidence)

Job “stress” (limited evidence, small effect size)

Low social support ( strong evidence for lack of support from fellow workers and supervisors influencing response to LBP)

Question 16

LBP in athletes

Answer 16

Prevalence of radiographic evidence of disc degeneration is higher in athletes than it is in nonathlete

Unclear whether this correlates with a higher rate of back pain

In general, the prevalence of spondylolysis is not higher in athletes than it is in nonathletes, although participation in sports involving repetitive hyperextension maneuvers, such as gymnastics, wrestling, and diving, appears to be associated with disproportionately higher rates of spondylolysis.

Bono, 2004

Question 17

What do not appear to be risk factors?

Answer 17

Height

Overweight

Losing weight may help with reducing LBP

Wrong build

Legs of unequal length (> 2 cm)