ObjectivesWe investigated the association of specific serum amino acids (AAs) with the odds of arsenic-induced skin lesions (AISL) and their ability to distinguish patients with AISL from people chronically exposed to arsenic.DesignCase–control study.SettingThree arsenic-exposed villages in Wuyuan County, Hetao Plain, Inner Mongolia, China were evaluated.ParticipantsAmong the 450 residents aged 18–79 years, who were chronically exposed to arsenic via drinking water, 56 were diagnosed as having AISL (defined as cases). Another 56 participants without AISL, matched by gender and age (±1 year) from the same population, were examined as controls.Main outcome measures and methodsAA levels were determined by ultra-high-performance liquid chromatography–quadrupole time-of-flight mass spectrometry-based metabolomics analysis. Potential confounding variables were identified via a standardised questionnaire and clinical examination. Multivariable conditional logistic regression model and receiver operating characteristic curve analyses were performed to investigate the relationship between specific AAs and AISL.ResultsTryptophan and phenylalanine levels were negatively associated with AISL (p<0.05). Compared with that in the first quartile, the adjusted OR of AISL in the second, third and fourth quartiles were decreased by 44%, 88% and 79% for tryptophan and 30%, 80% and 80% for phenylalanine, respectively. The combination of these two higher-level AAs showed the lowest OR for AISL (OR=0.08; 95% CI 0.02 to 0.25; p<0.001). Furthermore, both AAs showed a moderate ability to distinguish patients with AISL from the control, with the area under the curve (AUC; 95% CI) as 0.67 (0.57 to 0.77) for tryptophan and 0.70 (0.60 to 0.80) for phenylalanine (p<0.05). The combined pattern with AUC (95% CI) was 0.72 (0.62 to 0.81), showing a sensitivity of 76.79% and specificity of 58.93% (p<0.001).ConclusionsSpecific AAs may be linked to AISL and play important roles in early AISL identification.Trial Registration numberNCT02235948.
Keratotic Skin Lesions and Other Risk Factors Are Associated with Skin Cancer in Organ-Transplant Recipients: A Case–Control Study in The Netherlands, United Kingdom, Germany, France, and Italy
