Low back pain/prolapsed lumbar intervertebral disc.
Low back pain is common throughout the adult years in both men and women; first episodes most frequently occur among people in their 20s and 30s. Prolapsed lumbar disc most often affects individuals in the age range 25-45 years; prolapses occur infrequently in persons below 20 years or over 65 years. Major risk factors for low back pain in general and for prolapsed disc specifically include frequent lifting of objects weighing 25 pounds or more, especially if the objects are lifted with the arms extended and with the knees straight and if the lifting is done while the body is twisted; exposure to whole-body vibration, including driving motor vehicles; cigarette smoking; and, for prolapsed lumbar disc, narrow lumbar vertebral canals. Possible risk factors for which the evidence is weak or inconsistent include frequent stretching, reaching, pulling, and pushing on the job; sedentary occupations; jobs in which workers stay in one position for long periods of time; recent employment in a physically demanding job; jobs requiring frequent twisting without lifting; tallness; heredity; extent of forward flexibility in the lumbar area; lack of physical fitness; pregnancies; psychological symptoms; and frequent participation in bowling. The methods suggested to date with the greatest potential for prevention include modification of jobs so as to reduce exposure to known occupational risk factors, and careful selection of workers by such means as strength testing for the particular job for which they are to be employed.