Variation in Arsenic metabolism in schistosomiasis associated bladder pathology in a rural community, Eggua, Ogun State, Nigeria

Exposure to toxic inorganic Arsenic (iAs) in areas endemic for urogenital schistosomiasis may confer increased risk for bladder cancer. The severity of the adverse effects of iAs however depends on its metabolism, which is highly variable among individuals. Genetic polymorphism in Arsenic (+3) Methyl Transferase enzyme, accounts significantly for these variations. To investigate the relationship of AS3MT gene polymorphisms and Arsenic metabolism to schistosomiasis and/or associated bladder pathology, 119 individualsfrom Eggua in southwest Nigeria were recruited for this study. Screening for schistosomiasis and bladder pathology was done by microscopy and ultrasonography respectively. Wagtech Digital Arsenator was used to assess total urinary arsenic concentrations and thus determine the level of arsenic exposure. The single nucleotide polymorphism AS3MT/Met287Thr T>C (rs11191439) was genotyped using Alelle-Specific PCR. Of the participants who tested positive for schistosomiasis, 33.3% exhibited bladder pathology. Total urinary arsenic concentration in 80% of the participants was above the WHO limit of 0.05mg/L. The Met287Thr allelic distribution conformed to the Hardy-Weinberg equilibrium (X2= 0.161, P> 0.05). Observed allelic frequencies were 0.96 and 0.04 for wild-type T and mutant C alleles respectively. There was no significant relationship between AS3MT SNP, arsenic concentrations and schistosomiasis associated bladder pathology. In conclusion, the community is highly exposed to arsenic, although with a possible genetic advantage of increased AS3MT catalytic activity. However, we see the need for urgent intervention as inter-individual differences in arsenic metabolism may influence the bladder pathology status of individuals in the community. And although urogenital schistosomiasis is waning in Eggua, it is not known what synergy the infection and high arsenic exposure may wield on bladder pathology.

Alcohol Consumption Moderated the Association Between Levels of High Blood Lead or Total Urinary Arsenic and Bone Loss

Metal exposure and lifestyle are important risk factors for osteoporosis. Our study aimed to investigate the association between red blood cell lead and cadmium, total urinary arsenic, and plasma selenium levels and bone mineral density (BMD). In addition, we explored whether alcohol and coffee consumption modified the association between BMD and metals and metalloids. In total, 437 participants who underwent adult or senile physical examinations were recruited. Bone loss was defined as a calcaneus BMD T-score of <-1. Blood cadmium and lead and plasma selenium levels were measured using inductively coupled plasma mass spectrometry. Levels of urinary arsenic species were determined using high-performance liquid chromatography–hydride generator–atomic absorption spectrometry. The total urinary arsenic level was defined as the sum of the levels of urinary arsenic species. The BMD T-scores decreased significantly with increasing blood lead levels. The BMD T-scores also showed a downward trend with increasing total urinary arsenic levels. The odds ratio (OR) and 95% confidence interval (CI) for bone loss in patients with blood lead levels >57.58 versus 35.74 μg/dL were 1.98 and 1.17–3.34. In addition, the greater the lead or arsenic exposure and alcohol intake was the higher the OR for bone loss with multivariate ORs of 2.57 (95% CI 1.45–4.56) and 2.96 (95% CI 1.67–5.22), respectively. To the best of our knowledge, this study is the first to demonstrate that high total urinary arsenic or blood lead levels and frequent or occasional alcohol consumption had a significant multiplicative interaction for increasing the OR for bone loss.

Arsenic Exposure and Melanoma Among US Adults Aged 20 or Older, 2003-2016

Objectives Chronic exposure to arsenic has been reported as a risk factor for nonmelanoma skin cancer, notably squamous cell carcinoma. However, current knowledge is limited about the association between arsenic exposure and melanoma. Our objectives were to (1) measure the association between total urinary arsenic levels and melanoma compared with nonmelanoma skin cancer and no cancer and (2) analyze the association between water source and melanoma and nonmelanoma skin cancer. Methods We collected cross-sectional data from the 2003-2016 cycles of the National Health and Nutrition Examination Survey. We conducted univariate and multivariate logistic regressions. To evaluate the possible association of skin cancer with source of tap water, we calculated odds ratios for participants with melanoma and nonmelanoma skin cancer, compared with participants with no cancer. Results White race, higher education, higher socioeconomic status, and smoking history were associated with melanoma and nonmelanoma skin cancer in the full study population. After adjusting for age and race/ethnicity, the adjusted odds ratio of participants with >50 μg/L of total urinary arsenic for melanoma or nonmelanoma skin cancer was 1.87 (95% CI, 0.58-6.05) and 2.23 (95% CI, 1.12-4.45) times higher compared with no cancer, respectively. Participants with nonmelanoma skin cancer had 2.06 increased odds of reporting a nonmunicipal water source compared with participants without cancer. Conclusions We did not find a relationship between the incidence of melanoma and exposure to arsenic among US adults. Nonmunicipal water sources were associated with nonmelanoma skin cancer and should be further investigated.