Sage Journals: Discover world-class research

Abstract

When a dose-response experiment is conducted, the enhanced responses can be observed at low doses. This phenomenon is often called hormesis. The enhanced responses at low doses does not necessarily mean the existence of hormesis. It is important to conduct statistical analyses to determine whether a departure from monotonic relationships is significantly different from the chance occurrence. This paper introduces a non-parametric rank testto detecthormesis. To illustrate the use ofthis method, we apply it to the data from a Whole Effluent Toxicity test. We demonstrate that the occurrence of hormesis can be statistically evaluated by using this non-parametric rank test.

Keywords

dose response hormesis non-parametric rank test umbrella hypothesis Whole Effluent Toxicity

References

1 Calabrese EJ , Baldwin LA. Chemical hormesis: its historical foundations as a biological hypothesis . Hum Exp Toxicol 2000; 19: 2-31 .

2 Bukowski JA , Lewis RJ. Hormesis and health: a little of what you fancy may be good for you . Sout Med J 2000; 93: 371-374 .

3 Cameron JR , Moulder JE. Proposition: radiation horesis should be elevated to a position of scientific respectability . Med Phys 1998; 25: 1407-1410 .

4 Calabrese EJ , Baldwin LA. Radiation hormesis: its historical foundations as a biological hypothesis . Hum Exp Toxicol 2000; 19: 41-75 .

5 Davis JM , Svendsgaard DJ. U-shaped dose-response curves: their occurrence and implications for risk assessment . J Toxicol Environ Health 1990; 30: 71-83 .

6 Bailer AJ , Oris JT. Incorporating hormesis in routine testing of hazards . Hum Exp Toxicol 1998; 17: 247-250 .

7 Foran JA. Regulatory implications of hormesis . Hum Exp Toxicol 1998; 17: 441-443 .

8 Teeguarden JG , Dragan YD , Pitot HC. Implications of hormesis on the bioassay and hazard assessment of chemical carcinogens . Hum Exp Toxicol 1998; 17: 254-258 .

9 Sielken, Jr, RL , Stevenson DE. Some implications for quantitative risk assessment if hormesis exists . Hum Exp Toxicol 1998; 17: 254-258 .

10.

10 Ewijk PHV , Hoekstra JA. Calculation of the EC50 and its confidence interval when subtoxic stimulus is present . Ecotoxicol Environ Saf 1993; 25: 25-32 .

11.

11 Brain P , Cousens R. An equation to describe dose responses where there is stimulation of growth at low doses . Weed Res 1989; 29: 93-96 .

12.

12 Jonckheere AR. A distribution-free k-sample test against ordered alternatives . Biometrika 1954; 41: 133-145 .

13.

13 Mack GA , Wolfe DA. K-sample rank tests for umbrella alternatives . J Am Stat Assoc 1981; 76: 1 75-181 .

14.

14 Hollander M , Wolfe DA. Non-parametric Statistical Methods, 2nd edition. John Wiley and Sons, Inc., New York , 1999.

15.

15 Simpson DG , Margolin BH. Recursive non-parametric testing for dose-response relationships subject to downturns at high doses . Biometrika 1986; 73: 589-596 .

16.

16 Rom DM , et al. On closed test procedures for dosresponse analysis . Stat Med 1994; 13: 1583-1596 .

17.

17 Buning H , Kossler W. Power of some tests for umbrella alternatives in the multi-sample location problem . Biom J 1997; 39: 481-494 .

18.

18 Klemm DJ , et al. Short-term methods for estimating the chronic toxicity of effluent and receiving waters to marine and estuarine organisms, 2nd edition. EPA/600/ 4-91/003, 1994.

19.

19 Grothe DR , Dickson KL , Reed-Judkins DK (Eds), Whole Effluent Toxicity Testing: An Evaluation of Methods and Prediction of Receiving System Impacts. Society of Environmental Toxicology and Chemistry, 1995.

20.

20 Bailer AJ , Oris JT. Defining the baseline for inhibition concentration calculations for hormetic hazards . J Appl Toxicol 2000; 20: 121-125 .

21.

21 Barlow RE , et al. Statistical Inference Under Order Restrictions. Wiley, New York , 1972.

Detecting hormesis using a non-parametric rank test

Abstract

Keywords

References