This prospective general population study hoped to determine if non-occupational physical factors increased the risk of new episodes of low back pain (LBP). The authors looked at 2,715 subjects who had no back pain during the previous 30 days. The researchers evaluated their overall health, stress on the spine (in terms of weight, height, and activity), smoking status, psychological stress, and self-rated physical activity.
A year later, the authors followed up with another survey if the patient did not consult a physician in those 12 months. 1,540 patients responded to the follow-up survey; the 1066 who did not reply tended to be younger, less physically active, and more likely a smoker.
594 of 1649 (36%) had experienced an episode of low back pain. 254 patients reported their first episode ever. 37% of the men and 48% of the women who had a back pain episode had their first encounter with LBP over the 12-month period.
In comparing incident rates and surveys, the authors concluded that a poor rating of overall health at the initiation of the study predicted a new occurrence of back pain in the following year—regardless of the patient's history with the condition. As well, the risk for women increased with heavier weight. Yet, they also found factors which did not influence the probability of a future episode: Current smokers were no more likely to have an episode than former smokers or nonsmokers, and less physically active participants were no more likely to have an episode than more physically active subjects. The authors conclude:
"The major risk for new episodes of low back pain identified in the current prospective investigation, apart from poor self-rating of physical health, was excess weight in women. The extent to which physical activity aids weight control, may protect against low back pain in the long-term, and is beneficial for other reasons is an argument for promoting it in general. To complement this argument, this observational study has provided evidence that physical activity outside the workplace does not constitute a major hazard for low back pain in the short term."
Croft PR, Papageorgiou AC, Thomas E, et al. Short term physical risk factors for new episodes of low back pain. Spine 1999;24(15):1556-1561.