Presentations

Abstract

Introduction

Benzophenone-3(BP3), an ingredient in sunscreens, is absorbed through the skin, excreted in the urine, and causes hormone disruptions. Conversely, as BP3 leaves a minimal white cast on the skin, is less greasy, and is more water-resistant, it is widely used in high-quality costly sunscreens. Household income influences sunscreen purchase and use. Because the relationship between BP3-containing sunscreen use and household income is not well-studied, we examined this relationship in a large cohort of the US population.

Methods

We used the continuous NHANES data from 2003-2016. Creatinine-normalized urinary BP3 (CnBP3) levels were calculated from urinary BP3 and creatinine to account for urinary dilution/concentration. The household income to poverty threshold ratio (HIPR) was used to account for the effect of inflation. To examine the relationship between CnBP3 and HIPR, we used generalized linear models (GLMs) with log-link and gamma distributions to account for the long right-hand tail of the CnBP3 distribution. Missing data were imputed using multiple imputations by chained equations with a Gibbs-like algorithm. Models were adjusted for age, gender, race, education level, season, and sunscreen use.

Results

Of the 16691 study participants, 8404(50.3%) were females, 6561(39.3%) were Whites, and 3949(23.7%) were Blacks. The mean(SD) age was 36.6(22.7) years, and median(IQR) CnBP-3 were 12.2(44.9) μg/gm. In unadjusted GLMs, CnBP3 levels were 54% lower in the 16-25 age-group than the 6-15 age-group (95%CI=-0.82%, -0.25%; P<0.001); there was no significant difference between 6-15 and rest of the age-groups. Females had 2.2-times higher CnBP-3 than males (95%CI=1.57, 3.00; P<0.0001). Blacks had 67% lower (95%CI=-0.76%,-0.55%; P<0.001) and Hispanics had 44% lower (95%CI=-0.56%, -0.28%; P<0.001) CnBP-3 than Whites. Sunscreen-users had 5.9-times higher CnBP3 than non-users (95%CI=4.67, 7.48; P<0.001). Finally, in unadjusted models, participants with HIPR >4, had over 4.23-times higher CnBP3 than those with HIPR<1 (95%CI=3.10, 5.78; P<0.001) and this association remained significant after adjustment; participants with HIPR>4 had 2.06-times higher CnBP-3 than those with HIPR<1 (95%CI=1.53, 2.77; P<0.001).

Conclusion

We found a statistically significant association between HIPR categories and CnBP3. This association may allow the study of the most effective strategies to reduce BP3 exposure and protect the health of high-exposure populations.