Low back pain is often triggered by some combination of overuse, muscle strain, or injury to the muscles and ligaments that support the spine. Less commonly, low back pain is caused by illness or spinal deformity.

A risk factor is something that increases your chances of having back pain. More risk factors means you have a higher chance of having back pain.

Risk factors that you cannot change include:

• Being middle-aged or older.
• Being male.
• Having a family history of back pain.
• Having had a previous back injury.
• Being pregnant. A woman's back is significantly stressed by carrying a baby.
• Having had compression fractures of the spine.
• Having had previous back surgery.
• Having spine problems since birth (congenital spine problems).

Risk factors that you can change with lifestyle changes or medical treatment include:

• Not getting regular exercise.
• Doing a job or other activity that requires long periods of sitting, lifting heavy objects, bending or twisting, repetitive motions, or constant vibration, such as using a jackhammer or driving certain types of heavy equipment.
• Smoking. Smokers are more likely than nonsmokers to have low back pain.
• Being overweight. Excess body weight, especially around the waist, may put strain on your back, although this has not been proven. But being overweight often also means being in poor physical condition, with weaker muscles and less flexibility. These can lead to low back pain.
• Having poor posture. Slumping or slouching alone may not cause low back pain. But after the back has been strained or injured, bad posture can make pain worse. "Good posture" generally means your ears, shoulders, and hips are in a straight line. If this posture causes pain, you may have another condition such as a problem with a disc or bones in your back.
• Being under stress. Stress and other emotional factors are believed to play a major role in low back pain, particularly chronic low back pain. Many people unconsciously tighten their back muscles when they are under stress.
• Having long periods of depression.
• Using medicines long-term that weaken bones, such as corticosteroids.