Consumption of water contaminated by nitrate and its deleterious effects on the human thyroid gland: a review and update.

Nowadays, the nitrates have been established as carcinogenic components due to the endogenous formation of N-nitroso compounds, however, the consumption of water contaminated with nitrates has only been strongly related to the presence of methemoglobinemia in infants, as an acute effect, leaving out other side effects that demand attention. The thyroid gland takes relevance because it can be altered by many pollutants known as endocrine disruptors, which are agents capable of interfering with the synthesis of hormones, thus far, it is known that nitrates may disrupt the amount of iodine uptake causing most of the time hypothyroidism and affecting the metabolic functions of the organism in all development stages, resulting in an important health burden for the exposed population. Here, this review and update highlighted the impact of consumption of water contaminated with nitrates and effects on the thyroid gland in humans, concluding that nitrates could act as true endocrine disruptor.

CHRNA3 rs1051730 and CHRNA5 rs16969968 polymorphisms are associated with heavy smoking, lung cancer, and chronic obstructive pulmonary disease in a mexican population.

BACKGROUND AND PURPOSE: Smoking is a major public health problem worldwide. Polymorphisms in CHRNA3, CHRNA5, and CHRNB4 receptors play a critical role in nicotine dependence, lung cancer (LC) risk, and chronic obstructive pulmonary disease (COPD). This study characterized the CHRNA3 rs1051730 and CHRNA5 rs16969968 polymorphisms in a Mexican population and its association with nicotine dependence, LC, and COPD. METHODS: The study included 312 healthy individuals, 74 LC cases and 117 COPD cases. Genotyping was performed using TaqMan probes, and the data were analyzed using logistic regression adjusted for covariates. RESULTS: The polymorphism CHRNA3 rs1051730 and CHRNA5 rs16969968 were in the Hardy-Weinberg equilibrium and the allelic frequency of the A allele was 0.15, for both polymorphisms. The smokers were stratified in heavy smokers and moderate/light smokers, and we found in A alleles an OR = 2.86 (P = 0.01) to CHRNA3 rs1051730 and OR = 3.12 (P = 0.03) to CHRNA5 rs16969968. In addition, the A alleles in CHRNA3 rs1051730 and CHRNA5 rs16969968 were associated with the risk for LC (OR = 1.66, P = 0.07 and OR = 1.57, P = 0.1, respectively) and for COPD (OR = 2.04, P = 0.01 and OR = 1.91, P = 0.02, respectively). CONCLUSION: CHRNA3/5 polymorphisms are associated with nicotine dependence, LC, and COPD in Mexicans.