Nonmelanoma skin cancer tied to lower Alzheimer's risk

(HealthDay)—Older individuals with nonmelanoma skin cancer (NMSC) seem to have a significantly reduced risk of developing Alzheimer's disease (AD), according to a study published online May 15 in Neurology.

Robert S. White, from the Albert Einstein College of Medicine in Bronx, N.Y., and colleagues examined the correlation of NMSC and AD using data from annual assessment for 1,102 community-residing adults (mean age, 79 years at enrollment). Correlations were examined in three nested outcomes groups: only AD (probable or possible AD as the sole diagnosis); any AD (probable AD or possible AD, as well as mixed AD/vascular dementia); and all-cause dementia.

The researchers found that, after adjustment for demographics, hypertension, diabetes, and coronary heart disease, prevalent NMSC correlated with a significantly reduced risk of only AD (hazard ratio, 0.21). For 769 individuals, APOE ε4 genotypes were available. When the number of APOE ε4 alleles was included in the model the association was similar in magnitude, but was no longer significant. NMSC was not significantly associated with subsequent development of any AD or all-cause dementia.

"We deduce Alzheimer's-specific neuroprotection, because the effect is attenuated or eliminated when considering less-specific diagnoses such as AD with another diagnosis (any AD) or all-cause dementia," the authors write. "Further investigation is necessary to elucidate the biological and psychosocial basis for the reduced Alzheimer's risk associated with NMSC."

Several authors disclosed financial ties to the pharmaceutical and cognitive technology industries.