SANDRA MILENA COLORADO YOHAR¹, José María Huerta Castaño¹, Pilar Amiano², Eva Ardanaz³, María José Sánchez⁴, MARIA DOLORES CHIRLAQUE¹

(1) INVESTIGACIÓN EN EPIDEMIOLOGÍA Y SALUD PÚBLICA, IMIB, España
(2) Instituto de Investigación Sanitaria. San Sebastián, España. Subdirección de Salud Pública. San Sebastián, España. CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, España, España (País Vasco)
(3) Instituto de Salud Pública de Navarra. IdiSNA, Pamplona, España. CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, España, España (Comunidad Foral de Navarra)
(4) Escuela Andaluza de Salud Pública, Granada, España. Instituto de Investigación Biosanitaria de Granada (ibs.GRANADA). Universidad de Granada. España. CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, España., España (Andalucía)

Potential associations of bisphenol A (BPA) with socio-economic factors have been poorly studied. The aim was to evaluate the relationship between serum BPA and educational level in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Murcia study.

The EPIC-Murcia cohort consists of 8,515 healthy volunteers, recruited in 1992-1996 and followed-up for over 20 years. The analysis included a random sub-cohort of 988 participants without missing data on BPA or educational level. Data on the highest education attained, plus dietary and life-style variables were collected in face-to-face interviews. Anthropometric measurements (weight, height, and waist circumference) were taken using standard methods. Serum BPA concentrations were measured in frozen serum samples using UHPLC-MS/MS. Geometric means (with 95% confidence intervals) were calculated by educational level and sex, and differences evaluated with Kruskall-Wallis tests. Sex-specific logistic regression models were applied to estimate the odds ratio of presenting higher BPA concentrations (upper quartile), by educational level, adjusted by age and body mass index (BMI).

70% of the sample had detectable BPA concentrations (LOD: 0.2 ng/ml). The sample geometric mean was 1.11 ng/ml (P75=3.90 ng/ml). Women with higher educational level had significantly lower BPA concentrations in univariate analyses (p<0.001). Multivariate logistic models showed that women with higher education were less likely to have higher concentrations of BPA (ORunivsersity = 0.36, 0.14-0.92), with a significant inverse trend across categories (ORper-category change = 0.69, 0.52-0.91). No associations were found in men.

Our results showed an inverse independent association between serum BPA concentrations and educational level in women. Further studies should evaluate the relevance of these findings to partially account for the socio-economic inequalities in cancer incidence