Homelessness Tied to Increased Skin Condition Rates, Decreased Skin Cancer Rates

While homelessness is associated with a reduced risk for skin cancer diagnosis, an association exists between homelessness and specific skin conditions, according to study findings published in British Journal of Dermatology.

Researchers conducted a population-based cohort study to explore the association between homelessness and type of consultation, prescribed medication, and diagnosed skin conditions, including diagnostic subgroups (ie, atopic dermatitis, psoriasis, acne, hidradenitis suppurativa, malignant neoplasms, rosacea, and nonmelanoma skin cancer).

Researchers in Denmark conducted a nationwide, register-based cohort study that included 5,054,238 individuals (50.6% women; start mean age, 39.4±21.1 years) aged 15 years and older at some point during the study period from January 1999 through December 2018 living in Denmark. Poisson regression analysis was used to calculate adjusted incidence rate ratios (aIRRs) adjusted for sex, age, and calendar time. A second model included psychiatric disorders, alcohol and any drug use disorder.

The exposure was homelessness measured by contact with a homeless shelter during the study period, data gathered from the Danish Homeless Register, which recorded all contacts to homeless shelters in Denmark since January 1999. The primary endpoint was hospital-based diagnosis of any skin condition recorded in the Danish National Patient Register. Secondary endpoints included prescriptions for any dermatological treatment, data gathered from the Danish National Prescription Registry.

Among a total of the study population, 759,991 (15.0%) received a skin condition diagnosis and 38,071 (0.7%) individuals experienced at least 1 episode of homelessness (median age, 36.7 years) during the follow-up period. A total of 6333 individuals experienced homelessness and skin condition, which translated to an incidence rate of 21.7 per 1000 person-years. The incidence rate among individuals without homeless shelter contact was 10.3 per 1000 person-years. The researchers noted an IRR 2.31-times higher (95% CI, 2.25-2.36) of any diagnosed skin condition was associated with homelessness.

Homelessness was associated with a reduced IRR of skin cancer diagnosis (aIRR, 0.76; 95% CI, 0.71-8.82). Among all individuals experiencing homelessness, the researchers noted 2.8% (95% CI, 2.5-3.0) had a skin neoplasm diagnosis vs 5.1% (95% CI, 4.9-5.3) in those not experiencing homelessness by the end of follow-up.

Among people experiencing homelessness, there was a higher absolute risk for any diagnosed skin condition: 2.9% [95% CI, 2.7-3.1] in individuals with homeless shelter contact by 1 year of follow-up vs 0.8% [95% CI, 0.8-0.9] in those without homeless shelter contact. There was a skin condition diagnosis by the end of follow-up in 27.0% of individuals experiencing homelessness and 17.2% of individuals who were not experiencing homelessness.

During the first year from first contact, 5 or more shelter contacts associated with the highest aIRR of any diagnosed skin condition (7.33; 95% CI, 5.57-9.65) vs those without shelter contacts. In people experiencing homelessness, the cumulative probability was highest for infections of the skin and subcutaneous tissue (14.0%), erysipelas (7.6%), and ulcer (4.3%).

Homelessness was associated with lower aIRRs of immunosuppressive and other systemic treatments (0.56; 95% CI, 0.52-0.61) and light therapy (0.77; 95% CI, 0.69-0.86), and increased IRRs of prescriptions for antivirals, antihistamines, and scabies treatment.

Study limitations include the exclusion of homeless individuals not using shelters, unaccounted-for severity or chronicity of skin conditions, and using prescriptions as proxy for medication use.

“Individuals experiencing homelessness have high rates of most diagnosed skin conditions, but a lower occurrence of skin cancer diagnosis,” the study authors conclude.