Low back pain (LBP) is the leading cause of disability in adults under 45 years of age, the second most common cause of missed work days after upper respiratory conditions, and the fifth most common reason for all visits to a physician. It is the number-one most common pain condition, the second being headaches. Jobs that are thought to increase the risk of low back pain include nursing, construction, factory work, farm work, law enforcement, firefighting, sanitation, sedentary office work, nursery school teaching, and occupational driving. Low back pain is the leading cause of expenditures for workers’ compensation. The economic burden for low back pain to American society is up to $200 billion annually, with one-third of this total occurring as direct medical costs and the remainder from lost productivity. Approximately 5% of low back pain patients account for 75% of these costs. Chronic pain of all types, including low back pain, costs American society up to $635 billion annually in both medical costs and lost productivity.
About 70% to 80% of all people will experience low back pain in their lives. Of these, approximately 70% will resolve in 6 to 12 weeks. Approximately 85% will have recurrences of low back pain. Approximately 7% will go on to have significant chronic pain.
The prevalence of back pain is highest in the age groups of 45 to 64 years old, yet people under 45 experience the most activity limitations. The majority of younger patients are men, while the majority of patients over 60 years old are women. Return-to-work rates for back pain are dismal for pain lasting 6 months or longer. For those out of work for 6 months, the return-to-work rate is 50%, and for those out of work for 1 year, the return-to-work rate is 25%. After 2 years of unemployment due to back pain, the return-to-work rate is nearly zero.
The literature demonstrates a higher prevalence of chronic back pain in those with depression, anxiety, substance abuse, somatization, and personality disorders. Major depression was found in 30% to 65% of chronic low back pain patients compared to the rate of depression in the general population of 5% to 17%. The relationship between obesity and the prevalence of back pain continues to be controversial. One study found that a BMI higher than 30 (obese) increased the risk for chronic low back pain by 20% but that this risk is reduced with exercise. A systematic review involving 56 studies found, at best, a very weak correlation between obesity and low back pain. On the other hand, exercise has been shown to reduce the risk of low back pain regardless of weight, while lack of exercise increases the risk for low back pain. Smoking has been independently linked in some studies to an increased risk of chronic low back pain.
Table 38-1 shows ranks ...