RESUMO
Both arsenic and cadmium are reported to be toxic to humans. The use of saliva as a biomarker of low-level exposures to these elements has not been adequately explored, and the putative relationship between exposure and obesity is unclear. This cross-sectional study aims to investigate the relationship between salivary arsenic and cadmium concentrations and their association with obesity. Arsenic and cadmium concentrations were analyzed in human saliva samples by Inductively Coupled Plasma-Mass Spectrometry on 270 randomly selected women who participated in the Arkansas Rural Community Health Study. Multivariable logistic regression was performed to evaluate the association between heavy metal concentrations and obesity. Stratified logistic regression was performed based on menopausal status. Generalized linear models were used to evaluate weight gain velocity. Significant positive associations were observed in postmenopausal women for both arsenic (OR = 4.43, 95% CI 1.91-10.28) and cadmium (OR = 2.72, 95% CI 1.23-5.99) concentrations, as well as significant trends among tertiles (p < 0.01 and p = 0.01, respectively). No relationship with obesity was evident among premenopausal women for either metal. A dose-response relationship was observed between increasing weight gain velocity and increasing metal concentrations. At concentrations well below governmental and industrial standards for acute toxicity, significant associations between obesity and concentration of these heavy metals are evident. The rate at which individuals gain weight is affected by metal concentrations and may play a role in the rapid increase in weight in postmenopausal women. These results might explain, in part, the missing variability in the increasing obesity pandemic in certain population exposed to these environmental toxicants.
RESUMO
BACKGROUND: Physical activity has been identified as a modifiable risk factor for breast cancer. Varying definitions of physical activity have made the evaluation difficult to analyze. In a state with high prevalence of obesity and elevated rates of breast cancer incidence and mortality, physical activity may be an important element for risk reduction. Women's participation in physical activity and the relation to breast cancer incidence has rarely been determined in the southern states where obesity are prevalent. METHODS: Associations between various levels of physical activity and incident breast cancer cases among 21,665 subjects residing in Arkansas from 2007-2018 were completed. Multivariate logistic regression was used to estimate the odds ratios (OR) and 95% confidence intervals (95% CI), adjusting for various risk factors such as age, alcohol use, education, region, ethnicity, age at menarche, ever had children, and history of breastfeeding and family history of breast cancer. Stratification on menopausal status was performed to observe any breast cancer differences within the different biological pathways. RESULTS: Among premenopausal subjects, inverse associations were observed among increase time in walking (OR =0.63, 95% CI: 0.36-1.11 and OR =0.47, 95% CI: 0.26-0.83) and overall weekly physical activity (OR =0.89, 95% CI: 0.50-1.57 and OR =0.52, 95% CI: 0.30-0.90) and breast cancer. No association was evident between the risk for breast cancer and physical activity among postmenopausal subjects. The relationship between physical activity and risk for breast cancer differed between menopausal statuses. The most apparent association was seen among premenopausal subjects with an increase in walking (P=0.01). CONCLUSIONS: Although physical activity has been demonstrated to have a beneficial effect on breast cancer prevention among postmenopausal women, results from this study do not sufficiently support the hypothesis in this population. Results varied among menopausal status as well as among different definitions of physical activity. Further investigation is needed to identify factors contributing to de-attenuating the relationships.
