Is Smoking a Risk Factor for PsA?

Cigarette smoking produces harmful effects throughout the body. Smoking introduces harmful chemicals into the lungs, which are circulated throughout the body. These chemicals can cause disease and have a negative impact on health. The most common health problems that cigarette smoking increases are heart disease, stroke, and lung cancer. Several studies have shown that smoking increases the risk of developing psoriatic arthritis and worsens the impact of the disease on people living with PsA.1,2

Smoking increases the risk of developing psoriatic arthritis

Smoking negatively impacts the immune system and inflammatory process. Several studies have found that smoking increases the risk of developing psoriatic arthritis among patients with psoriasis. One recent study documented that the risk of psoriatic arthritis increased with smoking status, quantity of cigarettes smoked, and duration of smoking (years) – the risk of developing psoriatic arthritis was greater with increasing quantities of smoking.1,3

Smoking increases the severity of psoriatic arthritis

There have been several clinical studies that have looked at the effects of smoking on current psoriatic arthritis patients. One Danish study found that patients with psoriatic arthritis who smoke are less likely to adhere to treatment regimens and have less relief from their symptoms. The clinical study followed patients who were starting treatment with biologics, specifically tumor necrosis factor-alpha (TNF-alpha) inhibitor drugs etanercept (Enbrel), infliximab (Remicade), or adalimumab (Humira). The patients were followed for a median time of 1.22 years. Researchers found that the patients with psoriatic arthritis who smoked had worse patient-reported outcomes, shorter treatment adherence, and poorer response to TNF-alpha inhibitors compared with non-smokers. The difference was most pronounced in men and in patients treated with infliximab or etanercept. Possible explanations for the adverse impact of smoking on psoriatic arthritis include increases in inflammatory cytokines (chemical messengers) such as TNF-alpha, interference with the treatment drug’s bioavailability (the rate and extent to which the drug is in the body), and alterations in absorption of the drug following injections.4

Other studies have also shown the negative effects of smoking on psoriatic arthritis. A Swedish study found that both current and past smokers who have psoriatic arthritis reported worse pain and fatigue and more painful areas on the body than those who had never smoked. A British study that looked at physical function in people with psoriatic arthritis found that smoking, older age at diagnosis, and delayed diagnosis all had a similar negative effect on the patients’ long-term physical function.2,6

The benefits of quitting

Quitting smoking has multiple benefits on health. By stopping smoking, the risk of developing smoking-related diseases is lowered and life expectancy is increased. The body responds well to quitting: in just 1 year after quitting smoking, the risk of having a heart attack drops sharply, and within 2 to 5 years, the risk of stroke can fall to the same as that of a nonsmoker.1

In the Danish study that evaluated the effect of smoking in patients with psoriatic arthritis who were given TNF-alpha inhibitors, researchers noted that patients who had stopped smoking more than four years before beginning treatment had very similar rates of adherence to treatment as those who had never smoked. This potential reversibility of the negative influence of smoking on psoriatic arthritis and its treatment highlights another benefit of quitting smoking.4

Written by: Emily Downward | Last reviewed: October 2016.
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