The most representative indicator of vitamin D status in clinical practice is 25(OH)D₃, but new biomarkers could improve the assessment of vitamin D status and metabolism. The objective of this study is to investigate the association of serum vitamin D metabolites and vitamin D metabolite ratios (VMRs) with potentially influential factors in premenopausal women. This is a cross-sectional study based on 1422 women, aged 39–50, recruited from a Madrid Medical Diagnostic Center. Participants answered an epidemiological and a food frequency questionnaire. Serum vitamin D metabolites were determined using an SPE–LC–MS/MS platform. The association between participant’s characteristics, vitamin D metabolites, and VMRs was quantified by multiple linear regression models. Mean 25(OH)D₃ concentration was 49.2 + 18.9 nmol/L, with greater deficits among obese, nulliparous, dark-skinned women, and with less sun exposure. A lower R2 ratio (1,25(OH)₂D₃/25(OH)D₃) and a higher R4 (24,25(OH)₂D₃/1,25(OH)₂D₃) were observed in nulliparous women, with high sun exposure, and those with low caloric intake or high consumption of calcium, vitamin D supplements, or alcohol. Nulliparous women had lower R1 (25(OH)D₃/Vit D₃) and R3 (24,25(OH)₂D₃/25(OH)D₃), and older women showed lower R3 and R4. Vitamin D status modified the association of the VMRs with seasons. VMRs can be complementary indicators of vitamin D status and its endogenous metabolism, and reveal the influence of certain individual characteristics on the expression of hydroxylase enzymes.

Arsenic (As) is a toxic metalloid widely distributed in the environment. Chronic exposure to As has been associated with the development of several types of cancer. However, its role in prostate cancer (PC) remains unclear. To evaluate the relationship between As exposure and the risk of PC, considering different clinical tumour classifications and genetic susceptibility, and to compare biomarkers that may reflect distinct exposure windows. We included 345 incident cases and 468 controls with available data on both urinary and toenail As concentrations within the MCC-Spain project. Toenail and urinary As levels were measured using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), respectively. Genetic susceptibility was assessed using a polygenic risk score (PRS) based on Single-Nucleotide Polymorphisms. Associations between As exposure and PC were examined using mixed-effects and multinomial logistic regression models. Higher toenail As concentrations were associated with increased risk of PC [odds ratio (OR) comparing the fourth to first quartile: 1.94; 95 % confidence interval (CI):1.23-3.06]. Stratified analyses by tumor classification showed consistent risk increases for advanced and aggressive tumors [ISUP3-5 Relative risk ratio (RRR) quartile 4vs.1: 2.86 (1.16-7.06); AJCC IIB-IV RRR: 2.58 (1.48-4.50); cT2-cT4 RRR: 3.05 (1.55-5.99)]. No clear association was found with urinary As concentrations. Interaction analyses showed no evidence of effect modification by PRS. Elevated toenail As levels were associated with an increased risk of PC, especially in advanced disease, suggesting that toenails represent a more reliable biomarker for assessing long-term As exposure.

Background/Objectives: The 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) cancer prevention recommendations benefit primary prevention and survivor outcomes. This study evaluated the adherence to these recommendations during the year prior to breast cancer diagnosis and identified related clinical and sociodemographic factors. Methods: A total of 915 patients with breast cancer were recruited from eight hospitals in four regions of Spain. The participants completed an epidemiologic questionnaire and a food frequency questionnaire. The compliance with the WCRF/AICR recommendations was assessed using a standardized score based on seven recommendations. Standardized prevalences and standardized prevalence ratios (SPRs) for moderate and high adherence were calculated based on participant characteristics using binary and multinomial logistic regression models. Results: The mean adherence was 3.5 points out of 7. The recommendations with the best and worst adherence were avoiding sugar-sweetened drinks (54.4% adherence) and maintaining a fiber-rich diet (4.4% consumed ≥30 g/day). The overall adherence was better in women aged ≥60 years (SPR = 1.55; 95% CI = 1.09–2.22), and worse in those with a caloric intake ≥2000 kcal/day (SPR = 0.48; 95% CI = 0.37–0.62) or ≥2 comorbidities (SPR = 0.66; 95% CI = 0.49–0.89). The adherence to maintaining a healthy weight was worse in those with ≥2 comorbidities and stage III-IV tumors. The physical activity adherence was worse in working women and those with ≥2 comorbidities. The alcohol restriction adherence was worse in smokers. Younger women, smokers and those with a low calorie intake were less adherent to the fruit/vegetable recommendation. The consumption of fiber and limited consumption of red/processed meat adherence was poor in all the subgroups. The adherence to a limited consumption of fast food and sugary drinks was worse in younger women and high-calorie-diet consumers. Conclusions: The differences in the adherence to recommendations according to patient characteristics justify the design of personalized interventions for breast cancer patients.