Researchers focused on a common cause of lower back pain known as lumbar spinal stenosis, which occurs when the spinal canal narrows, putting pressure on the spinal cord and nerves.
The condition often develops as people age, but nicotine’s constriction of blood flow and promotion of inflammation are believed to contribute to the process, the study authors write.
The participants in the Swedish study, however, were mostly in the prime of their lives, and, though they all worked in a labor-intensive industry, the smokers were far more likely to develop debilitating back injuries.
The researchers examined data on 331,941 construction workers who were part of a nationwide occupational health registry in Sweden.
Workers were followed for an average of more than three decades, starting when they were typically in their 30s, and 1,623 of them eventually had surgery for lumbar spinal stenosis.
Compared to people who never smoked, heavy smokers who went through at least 15 cigarettes a day were 46 percent more likely to have this spinal surgery, the study found.
For moderate smokers who had up to 14 cigarettes a day, the increased risk was 31 percent, while ex-smokers had 13 percent higher odds of surgery.
‘Smoking appears to be a risk factor for developing lower spine space narrowing that can lead to surgical treatment,’ said senior study author Dr Arkan Sayed-Noor, a researcher at Umea University.
Quitting smoking can reduce the risk,’ Sayed-Noor said.
While some previous research has linked smoking to worse outcomes from spinal surgery, the current study offers fresh evidence that it can also increase the odds that back pain will require surgery, Sayed-Noor added.
Overall, 44 percent of the study participants were non-smokers. Another 16 percent were former smokers, while 26 percent were moderate smokers and 14 percent were heavy smokers.
In the US, about 15 percent of the adult population still smokes.
The connection between smoking and spinal surgery persisted even after researchers accounted for other factors that can increase the odds of lower back pain such as aging and obesity.
Smoking damages the spine in several ways, researchers note in The Spine Journal. Nicotine can damage spinal tissue, weaken bones and make back pain worse.
The fact that it is nicotine, not just combustible tobacco, that was linked to back pain is particularly worrisome, since even safer e-cigarettes still use nicotine in their liquid cartridges.
Heavy smoking is also often accompanied by a sedentary lifestyle that may lead to muscle weakness and increase strain on the lower back.
One limitation of the study is that researchers lacked data on exercise habits, the authors note. Most of the construction workers in the study were men, and the results might be different for women.
Still, the findings add to evidence linking cigarettes to disc damage and back pain, said Dr Jean Wong, a researcher at the University of Toronto who wasn’t involved in the study.
‘There are multiple short and long-term health reasons for smokers to quit, and by quitting smoking, smokers can reduce their risk of back pain due to disc degeneration and spinal stenosis – which can be a debilitating problem in smokers,’ Dr Wong said.
‘Although it may take multiple attempts, quitting smoking is the best thing a smoker can do to minimize the risk of spinal stenosis and other health problems,’ said Dr Wong.
How does smoking harm the spine?
Smoking, or any nicotine use, damages several parts of cells of any kind, including the central nucleus.
The discs that connect each vertebrae in the spine help to absorb shock in the back, but, overtime the discs get softer and weaker, failing to cushion the back.
Back pain is largely caused by this degenerative process.
But smoking attacks and poisons the cells that make up these discs, and scientists think the toxic nicotine eats away at our shock absorption system.
Smoking also interferes with a sensory and hormonal system to make us more sensitive to pain.
The habit has also been linked to poorer bone density and slower healing for back fractures, both of which raise the risk of early death in older people significantly.