Sunscreen use associated with elevated prevalence of anti-nuclear antibodies in U.S. adults

Antinuclear antibody (ANA) prevalence in the U.S. population increased from 1988 to 2012, especially in white and more educated individuals. In adults ages 20-39 years from the National Health and Nutrition Examination Survey (NHANES) 2003-2004 and 2011-2012, ANA prevalence was previously associated with urinary concentrations of a common sunscreen ingredient, benzophenone 3, measured in winter. Spot urines may not capture relevant chronic exposures, thus we examined whether ANA was related to sunscreen use.

In a cross-sectional study of adults ages 20-59 (N = 416 ANA positive, 2656 ANA negative, by Hep-2 immunofluorescence, 1:80 dilution), we examined associations of ANA with reported sunscreen use when in the sun for 1 h or more. Logistic regression was used to calculate covariate-adjusted prevalence odds ratios (POR) and 95 % Confidence Intervals (CI), overall and stratified by demographic factors, season, and vitamin D. We explored associations and joint effects with other sun protective behaviors and sunburn in the past 12 months.

The association of ANA with sunscreen differed by age (interaction p = 0.004): for ages 20-39, we saw an exposure response (POR 2.61, 95 % CI 1.50, 4.24 for using sunscreen always or most of the time, and POR 1.85; 1.12, 3.05 for less frequent versus never-use; trend p < 0.001). These associations were more apparent in females (interaction p = 0.082), non-Hispanic white and black participants (vs. other race/ethnicity, interaction p = 0.023), and those with sufficient serum vitamin D (≥50 vs. <50 nmol/L, interaction p = 0.001). ANA was not associated with other protective behaviors and not confounded or modified by these behaviors or recent sunburn.

These cross-sectional findings showed frequent sunscreen was associated with ANA in younger adults, supporting the need for replication, and longitudinal studies with detailed exposure histories.