Prurigo Nodularis Significantly Associated With Obesity and Smoking

Prurigo nodularis is significantly associated with increased rates of obesity and cigarette smoking, according to study findings presented at the 2023 Annual Meeting of the American Academy of Dermatology (AAD), held from March 17 to 21, 2023, in New Orleans, Louisiana.

The role of modifiable lifestyle factors (cigarette smoking, alcohol use, and obesity) in patients with prurigo nodularis, a chronic neuroimmune skin condition characterized by intractable itch and multiple pruriginous lesions, is unknown. As of now, few therapeutic treatment options are available. Investigators sought to assess whether modifiable lifestyle risk factors of cigarette smoking, alcohol use, and obesity differ between patients with and without prurigo nodularis.

They initiated a cross-sectional analysis of a retrospective, propensity score matched cohort from The Health Improvement Network (THIN®), a medical record database representative of the general population in the United Kingdom. Patients with prurigo nodularis were propensity score matched 1:1 with controls based on sex, age, and race/ethnicity. Rates for patients with prurigo nodularis and controls were compared for cigarette smoking, alcohol use (>1 drink per day), and obesity.

To determine whether prurigo nodularis was associated with increased frequency of these lifestyle risk factors, they used multivariable logistic regression adjusted for sociodemographic characteristics. Patient data was available for smoking (96.2%), body mass index (75.0%), and alcohol use (51.5%).

They noted 6090 patients in the prurigo nodularis group propensity score matched with 6090 patients in the control group, the majority of whom were women (58.4%), White (86.5%), mean age 56.7 years. Only 4.5% of either patients or controls were Black, and race/ethnicity data was missing for more than 48% of each group. They found patients with prurigo nodularis vs controls were significantly more likely to be obese (35.0% vs 25.2%; P <.001), and smoke cigarettes (22.7% vs 18.6%; P <.001). No difference was seen between groups in alcohol use (74.1% vs 73.7%; P =.71).

In multivariable regression models, they found prurigo nodularis was associated with increased risk of obesity (adjusted odds ratio (aOR), 1.61; 95% CI, 1.48-1.77) and increased risk of cigarette smoking (aOR, 1.30; 95% CI, 1.18-1.42).

Study limitations include the nature of retrospective study design, cross-sectional design, propensity score matching 48.2% of participants with missing race/ethnicity data with other participants with the same missing data doesn’t make them well-matched and may lead to lack of generalizability.

Among patients with prurigo nodularis, the investigators concluded that “[prurigo nodularis] was associated with significantly increased rates of cigarette smoking and obesity.” They wrote “Further research is necessary to elucidate whether such lifestyle behaviors increase the risk of development and progression of [prurigo nodularis]. Dermatologists and general practitioners should consider screening, counseling, and referral for these factors to improve outcomes.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.