Low testosterone levels and sleeping fewer than seven hours per night were each independently associated with higher odds of psoriasis in a study of 4,060 adult men in the United States.
Investigators analyzed health records of male patients aged 18 and older collected between 2011 and 2014 through the National Health and Nutrition Examination Survey (NHANES). Men with testosterone levels below 300 nanograms per deciliter (ng/dL) were nearly three times more likely to report having psoriasis compared to those with normal levels. Similarly, those who slept less than seven hours per night had significantly increased odds of psoriasis.
After adjusting for age, race, body mass index (BMI), smoking, alcohol use, and common chronic conditions, both low testosterone and short sleep duration remained significantly associated with psoriasis.
Testosterone was measured via blood samples using isotope-dilution liquid chromatography–tandem mass spectrometry (ID-LC-MS/MS), the gold standard for hormone analysis. Sleep duration was self-reported based on average hours of sleep during weekdays. Psoriasis diagnosis was determined by whether a doctor or other health professional had ever told the participant they had the condition.
In fully adjusted models, men with low testosterone had an odds ratio (OR) = 2.97 (95% confidence interval (CI): 2.16–4.09). Men who slept fewer than 7 hours had an OR of 1.76 (95% CI: 1.33–2.35). These results suggest independent associations between both factors and psoriasis.
Subgroup analyses showed that the link between low testosterone and psoriasis was stronger in men aged 50 and older. The association between short sleep and psoriasis was more pronounced in men with obesity (BMI ≥30). No significant interaction was found with smoking status.
To test the consistency of the findings, investigators conducted a sensitivity analysis excluding men with testosterone levels above 1000 ng/dL. The associations remained statistically significant (testosterone OR = 2.98; sleep OR = 2.10), confirming the robustness of the results.
Non-linear analyses showed a steep rise in psoriasis risk at testosterone levels below 300 ng/dL, with no additional risk at very low levels. Psoriasis risk also increased as sleep duration dropped below 7 hours, but the benefit of longer sleep plateaued after 8 hours.
Although psoriasis status and sleep duration were self-reported—introducing potential for recall bias—standardized NHANES questionnaires were used to minimize this limitation.
Psoriasis is a chronic inflammatory skin disease that affects millions globally. These findings suggest that hormonal and sleep-related factors may influence psoriasis risk, especially in older or overweight men.
Further studies are needed to determine whether improving sleep or addressing low testosterone can help prevent or manage psoriasis.
Disclosure: The authors reported no conflicts of interest.