Answer:
Hepato- and nephrotoxicity of fluoride have been demonstrated in animals, but few studies have examined potential effects in humans. This population-based study examines the relationship between chronic low-level fluoride exposure and kidney and liver function among United States (U.S.) adolescents. This study aimed to evaluate whether greater fluoride exposure is associated with altered kidney and liver parameters among U.S. youth.
This cross-sectional study utilized data from the National Health and Nutrition Examination Survey (2013–2016). We analyzed data from 1983 and 1742 adolescents who had plasma and water fluoride measures respectively and did not have kidney disease. Fluoride was measured in plasma and household tap water. Kidney parameters included estimated glomerular filtration rate (calculated by the original Schwartz formula), serum uric acid, and the urinary albumin to creatinine ratio. Liver parameters were assessed in serum and included alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, blood urea nitrogen, gamma-glutamyl transferase, and albumin. Survey-weighted linear regression examined relationships between fluoride exposure and kidney and liver parameters after covariate adjustment. A Holm-Bonferroni correction accounted for multiple comparisons.
The average age of adolescents was 15.4 years. Median water and plasma fluoride concentrations were 0.48 mg/L and 0.33 μmol/L respectively. A 1 μmol/L increase in plasma fluoride was associated with a 10.36 mL/min/1.73 m2 lower estimated glomerular filtration rate (95% CI: −17.50, −3.22; p = 0.05), a 0.29 mg/dL higher serum uric acid concentration (95% CI: 0.09, 0.50; p = 0.05), and a 1.29 mg/dL lower blood urea nitrogen concentration (95%CI: −1.87, −0.70; p < 0.001). A 1 mg/L increase in water fluoride was associated with a 0.93 mg/dL lower blood urea nitrogen concentration (95% CI: −1.44, −0.42; p = 0.007).
Fluoride exposure may contribute to complex changes in kidney and liver related parameters among U.S. adolescents. As the study is cross-sectional, reverse causality cannot be ruled out; therefore, altered kidney and/or liver function may impact bodily fluoride absorption and metabolic processes.
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Rays of light that pass through the lens are brought closer together that’s because this lens is a converging lens.
Answer:
I believe the answer is D
Answer:
light is the independent variable, height of the plant is the dependent variable. Dependent is the effect that based on the independent.
Explanation:
lets break it down. 1) you want to know the effect of something you apply from one thing to another. Let say, if you grow your plants under the sunlight, the plants grow taller. In this case, the sunshine is the independent variable whereas the height of the plant/how tall it can grow is the dependent variable. 2)NOW, before i give the answer. The design of the question is not good for high school students. i think your teacher thinks "light" is the independent variable. 3)However, the question contains confounding variables in it because different lights might produce different effects to the height of the plants. If you want to test if plants are exposed to light grows taller than plants do not expose to light, then you should have all the lights are the same. 4) So, all the plants should be exposed to one certain light to avoid confounding. Confounding means that either red light and sunlight are both produce the same effect whereas the other colors do not help the plants to grow taller. 5)Your teacher should test one light at a time. So, if he is testing with all different colors of light, then light is the independent variable, and height of the plant is the dependent variable.
