Marta Laskowski, MD, on Cardiorespiratory Health and Threat of Psoriasis

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The association between low cardiorespiratory fitness (CRF) and an increased risk of negative health outcomes, including cardiovascular disease and all-cause mortality, is well established.

Results from a new long-term study on young men drafted into the Swedish military show that low CKD in adolescence is also a risk factor for psoriasis and psoriatic arthritis in adulthood. This analysis is the first to examine the relationship between emerging psoriasis and cardiorespiratory fitness, said Dr. Marta Laskowski from the University of Gothenburg and colleagues.

“This study presents unique data on the effects of objectively measured CRF on emerging psoriasis and psoriatic arthritis and adds psoriasis and psoriatic arthritis to the list of diseases associated with low CRF levels,” the authors wrote in PLOS One. The results also highlight “the importance of assessing cardiorespiratory fitness early in life,” they said.

For the prospective study, the researchers created a cohort of more than 1.2 million men, mean age 18.3, using Swedish military service data (1968-2005) for all who had undergone a physical exam at the time of admission. The authors used national patient registry data to track the cohort through either December 31, 2016 or a diagnosis of emerging psoriasis or psoriatic arthritis.

With a median follow-up of 31 years, 20,679 cases of psoriasis and 6,133 cases of psoriatic arthritis were diagnosed. A fitted analysis found a significant association between low CKD and invasive psoriasis and psoriatic arthritis with hazard ratios of 1.35 and 1.44, respectively.

In the following interview, Laskowski, also a resident doctor at the Sahlgrenska University Hospital, discussed the difference between physical activity and CRF and what the results mean for clinical practice.

Why did you decide to consider CKD in adolescence as a risk factor for psoriasis and psoriatic arthritis in men?

Laskowski: Psoriasis used to be considered a skin-only disease, but it is becoming more and more apparent that psoriasis is a multi-system disease. Patients with psoriasis are at increased risk of cardiovascular disease, just like people with low CRF, for example, are at increased risk of cardiovascular disease.

Although not much research has been conducted into the association between cardiorespiratory fitness and psoriasis, there is evidence that patients with psoriasis have lower cardiorespiratory fitness compared to the general population. However, to date no studies have been conducted to determine whether CRF levels affect the risk of developing psoriasis and psoriatic arthritis. We found this topic very interesting and important and this gap in our understanding inspired us to do this research.

How have previous studies affected our understanding of physical activity and psoriasis?

Laskowski: It is important to distinguish between physical activity and CRF. Although CKD is related to physical activity, genetics and other factors also affect it.

Recently, researchers found that physical inactivity does not remain a risk factor for mortality in correcting CRF status. Therefore, CRF, which provides an objective measure of cardiovascular function, appears to be a more important risk predictor of health events compared to physical activity.

Although somewhat limited by methodological issues, previous studies investigated the association between physical activity and emerging psoriasis. A large prospective, questionnaire-based study of female US nurses showed a lower risk of psoriasis in nurses with high levels of self-reported vigorous physical activity. However, both psoriasis diagnoses and physical activity have been self-reported.

A prospective, questionnaire-based, registry-based cohort study in older white US women supports these results and shows a lower risk of psoriasis in women who were regularly physically active between 1991 and 2004. In the present study, we used objective measurements of low CRF in late adolescence to determine whether CRF was associated with psoriasis and psoriatic arthritis in men.

Have there been similar studies in women?

Laskowski: To the best of our knowledge, there are no studies examining how CKD levels affect the risk of psoriasis or psoriatic arthritis in women. However, research into the effects of physical activity on psoriasis has mainly focused on women. Since psoriasis and psoriatic arthritis affect both men and women with no preference for either sex, we believe it is likely that our results apply to both women and men.

Can you explain the mechanisms behind the negative effects of low CRF?

Laskowski: The mechanisms are not fully understood. However, it has been suggested that in patients with psoriasis, dysfunction of the autonomic nervous system with increased sympathetic activity could be a driver of low CKD in psoriasis. The results of previous studies have been somewhat contradicting but suggest that impaired cardiovascular function in patients with psoriasis could affect CRF levels.

Although high CRF levels were associated with a more beneficial lipid profile, lower inflammation levels, lower blood pressure, and lower body mass index (BMI) compared to lower CRF levels, we found that the association between low CRF and psoriasis was independent of BMI . Other studies have reported similar results.

What are the implications for clinical practice?

Laskowski: We hope these novel results show that low CKD is a major risk factor for negative health outcomes, including psoriasis and psoriatic arthritis. A low CKI score is also linked to an increased risk of cardiovascular disease and mortality, and a high CKI score appears to protect against diabetes, some psychiatric and neurological disorders, and even some cancers. Nevertheless, in our experience, CRF is rarely discussed as a risk factor or assessed in the clinical setting. Given the negative health effects of low CRF, the introduction of a routine fitness measurement should be considered to identify at-risk patients and improve clinical management.

What’s next for your research?

Laskowski: We are currently conducting ongoing studies examining the effects of lifestyle factors such as obesity and stress on psoriasis.

Last updated on May 17, 2021

Disclosure

This study was funded by the Psoriasis Fund, the Sahlgrenska University Hospital Fund, the Wilhelm and Martina Lundgren Science Fund, and the Royal and Hvitfeldska Foundation. Laskowski and co-authors of the study stated that they did not have any potential conflicts of interest.