IS COMPARISON OF THE PREVALENCE OF DISEASE APPROPRIATE AS HEALTH INDICATOR BETWEEN TWO POPULATIONS? Bibliography 1. Keeling MJ, Rohani P. Modeling Infectious Diseases in Humans and Animals. 1st Ed. Princeton: Princeton University Press; 2007. 2. Rothman KJ. Epidemiology: An Introduction. Oxford: Oxford University Press. p. 53. 2012. 3. Moscicki EK. The prevalence of ‘incidence’ is too high. ASHA. 1984;26(8):39-40. 4. Szylkowska E, Kaste LM, Schreiner J, Gordon SC, Lee DJ. Comparison of systemic health conditions between African American and Caucasian complete denture patients. J Prosthodont. 2014;23(5):341-346. 5. Bjarnason S. High caries levels: problems still to be tackled. Acta Odontol Scand. 1998; 56(3):176-178. 6. Frencken JE, Sithole WD, Mwaenga R, Htoon HM, Simon E. National oral health survey Zimbabwe 1995: dental caries situation. Int Dent J 1999; 49(1): 3-9. 7. Pitts NB, Palmer JD. The dental caries experience of 5-, 12- and 14-year-old children in Great Britain. Surveys coordinated by the British Association for the Study of Community Dentistry in 1991/92, 1992/93 and 1990-91. Community Dent Health 1994; 11(1): 42-52. 8. Riordan PJ. Secular changes in treatment in a school dental service. Community Dent Health 1995; 12(4): 221-225. 9. Das D, Misra J, Mitra M, Bhattacharya B, Bagchi A. Prevalence of dental caries and treatment needs in children in coastal areas of West Bengal. Contemp Clin Dent. 2013; 4(4): 482-487. 10. Saravanan S, Kalyani V, Vijayarani MP, Jayakodi P, Felix J, Arunmozhi P, Krishnan V, Sampath Kumar P. Caries prevalence and treatment needs of rural school children in Chidambaram Taluk, Tamil Nadu, South India. Indian J Dent Res 2008; 19(3):186-190. Appendix (O/T), is the probability of old cases among screened cases; (C/T), is the probability of normal cases among screened cases. Mathematical Derivations We can express the prevalence of the disease D as follows: where N is the number of new cases O is the number of old cases T is the number of screen cases Equation (1) can be also presented in the form where C is the number of individuals free from the diseases, let T = N + O + C If we are dividing equation (2) by 2, we obtain where (N/T), is the probability of new cases among screened cases; STOMA.EDUJ (2014) 1 (2) is the probability of new cases among the screened population; here, the utilization of the same protocol of diagnose of a given disease D will lead to comparable probabilities irrespective of the populations under study. We know exactly what is going on as the cases will be diagnosed during screening, and all the cases have no idea that they have the disease before (Rational). The question about delay may rise at this point, but it will not affect the comparison. is the probability of the old cases among the screened popul ][ێ