Epidemiology in Public Health - Essay Example

? EPIDEMIOLOGY IN PUBLIC HEALTH Question d) Obtaining a history and other information from a group of people witha disease and also from a comparison group to determine the relative frequency of an exposure under study. Question 2 b) Less than 100 Question 3 c) Cross-sectional study Question 4 d) Incidence rates may be computed directly Question 5 d) Cohort study (prospective) Question 6 In deciding which method of study to use, the researchers are suppose to examine many factors in order to settle on a proper study method that will give the most reliable information about the study. This is owing to the fact that in most of the study it is the reliability and the viability of the study that becomes of interest (Friesen, 2006). Choice of the most appropriate study method do enhances the efficacy of the results and confers certain degree of authority in reporting the findings. As for the case in a) above; you wish to investigate whether the birth weight of babies is related to the mother’s smoking status (current smoker, ex-smoker, or never smoked). The study method that will be employed is the Quasi-study. This method will be used because it is the one that will be in a position to give us the information about the weight of the children in a suspected risk situation, after the intervention as well as for the study groups, i.e. those smoking, those who left smoking and those who have never smoked respectively (Friis & Sellers, 2009). In a Quasi-experiment, there are factors that can compromise the quality of the study, these factors include; the honesty of the people involved in the study, it always depends on the goodwill the participants to be honest as an individual may be in the study as a non-smoker for this case when she is currently smoking. Such kinds of dishonesty can make the results deviate in the sense that they will be treated otherwise (Hebel & Robert, 2006). To overcome these, the participants involved in the study should be given the ethical education of the study before they are involved in the study. In this case they will appreciate the importance of the study as well as giving honest disclosure regarding their position on the variable of interest. In the situation in b, you wish to investigate whether people who have worked in the factory of a chemical company producing toxic chemicals are more likely to develop a specific lung disease. This requires a kind of study that attributes certain outcomes to the risk factors hypothesized to the causative agent of the conditions. In this kind of research, retrospective cohort study will come in handy. In this kind of the study method, the researchers are able to look back and relate the outcome of a disease or a condition to certain specific exposures in the past. Just like any other study, retrospective method is faced with a couple of challenges that can compromise the viability of the results is no measures are put into place to mitigate on this. The challenges are confounding and biasness. Bias can amplify or reduce the cause or the effect of the risk factors. When there is doubt that such has occurred then the findings are always refuted and a new study commenced. Bias is an error that is rather systematic error that compromises on the quality of the results (Kang, 2007). The following can mitigate upon the effects of biasness; having several replicate groups in the study running concurrently, carrying out blinding during the study, what is referred to as standardizing the observations and using other variables corresponding to associations that are known. The other challenge in the study is the confounding. There is always no nexus between confounder and the exposure or the disease. In relation to that, researchers are only capable of mitigating on the effect of the confounders if they are known and measurable I the following ways; restricting candidates with confounding factors joining the study, randomizing and matching those individuals destined for equal confounders distribution. The use of multivariate analysis can also be used to check on confounders where working is only commenced if the confounders can be identified and are measurable (Kang, 2007). Question 7 Variables Dead Alive Total Continued smokers 19 135 154 Stopped smokers 15 199 214 Total 34 334 368 (a) The absolute risk of death for continued smokers and stopped smokers Absolute risk for the continued smokers =19/368 =0.051 Absolute risk for stopped smokers= 15/368 =0.040 With the figures obtained as those of the absolute risk, it shows that for out of the 368 individuals in the study the vulnerability in terms of absolute risk differs insignificantly with the continued smokers and the stopped smokers having the absolute risk as 0.051 and 0.040 respectively. (b) The relative risk of death for continued smokers compared with stopped smokers Relative risk = (a / (a+b)) / (c / (c+d)) Number with positive outcome: a Number with negative outcome: b Number with positive outcome: c Number with negative outcome: d Relative Risk = ad/bc (for continued smokers) = 19/199/135/15 = 0.010 Relative risk for stopped smokers: =15/135/199/19 = 0.010 The relative risk for the continued and stopped smokers is actually the same. c) The attributable risk for continued smokers Attributable risk=100*(Px*(RR-1))/(1+(Px*(RR-1))) = 100*(0.051(0.040-1))/(1+0.0951*(0.040-1))) =0.325 For stopped smokers =100*(0.040(0.051-1))/(1+0.040*(0.051-1))) = 0.256 The attributable risk of the continued smokers is greater than that of the stopped smokers, this shows that those who continue to smoke are much predisposed to heart attack than those who stopped. Outcome rate exposed (Pe) = a/(a+c) Outcome rate not exposed (Pu) = b/(b+d)  Relative risk (RR) = Pe/Pu Risk difference (RD) = Pe-Pu Estimate of population exposure (Px) = (a+c)/(a+b+c+d) =(19+15)/(19+135+15+199) = 0.0924 Question 8 I) Prevalence Rate = _number of existing cases of a disease during time period_ X constant Total population during time period =44/144*100 = 38.60% II) Sensitivity = persons with disease detected through surveillance/total persons disease Detected *100 = 15/44*100 =34.10 III) specificity= persons detected without a disease/total persons without a disease*100 =91/(8+91) = 0.919 IV) Positive predictive value= a/(a+b) =14/(14+8) = 0.6364 V) Negative Predictive Value= d/(c+d) = 91/(1+91) = 0.9891 In the repeat of the same with the different values the following results were obtained (for palpable breast masses) i) Prevalence rate=128/317*100 = 40.37% ii) Sensitivity= a/(a+c) =113/(113+8) =0.933 iii) Specificity= d/(b+d) =181/(15+181) = 0.923 iv) Positive predictive value=a/(a+b) =113/(113+15) =0.8828 v) Negative predictive value=d/(c+d) =181/(8+181) =0.957 Question 9 Considering the effect of lung cancer in the three towns, the incidence is relatively the same with the following percentage attributed to town A, B, and C respectively 2.8, 3.2, and 3.0. Breast cancer, town C has the least incidences of deaths, followed by town B and lastly by town A in the following percentage, 1.6, 2.4, and 3.7 respectively. On the other side, stomach and bowel cancer incidences in the three towns are spread in the following percentages in towns A, B, and C respectively 2.6, 1.8, and 2.4. In comparing the number of deaths in the three towns apportioned to the three different cancers, it is evidenced that there are some other diseases that claims a huge chunk of the population, either endemic or epidemic. In fact, cancer constitutes the lowest percentage of deaths in the towns, it can then be construed that other than medical conditions, there are other forms of diseases that claims deaths. These hypothesized deaths may be attributed to contagious and sporadic diseases. The claims can be corroborated by the fact that the mortality rate in the three towns, A, B, and C are 10.2, 11.8, and 8.5 respectively, this is above the contribution of the three cancers alone. It can also be projected that the population in the three towns may diminish because birth rate is lower than the mortality rate. The birth rate in the towns A, B, and C are as follows 1.6, 2.4, and 1.5 in percentage respectively. Question 10 In the randomized controlled trials involves a set of cohorts that are given different medical intervention and then followed for a period to re-examine the effect of the various intervention measures. In this sense, the method strives to establish the efficacy of the various medical interventions. To ensure that biasness reduced, blinding of the participant in the study would have improved on the reliability of the study given that in a randomized situation, it will now be difficult to register any form of prejudice that may culminate into biasness. Relative risk= (a / (a+b)) / (c / (c+d)) =(83/(83+61))/(18/(18+34)) =2.42 The relative risk calculated shows that the probability of the persons showing improvement after the administration of the drugs is 2.42. This furthers shows that the efficacy of acupuncture is feasible in reducing pain. Question 11 In developing a study to investigate, the risk factors associated with the cancers in the UK, retrospective method will be the most reliable option for the study. In retrospective study, the researchers are able to relate the causative agents of cancers with the possible risk factors in the earlier circumstances as well as the current predominant factors (Riegelman, 2005). In assessing the causative agent of cancer in children, the research would look into the various ways of possible cancer acquisition. The research would endeavor to establish the various forms of cancer and there possible ways through which they are contracted. Hypothesis of the study would be weather they arise from foodstuffs, genetics, or life style. In selecting the candidates for the study, the children will be taken from parents who have no history of cancers and are at the same time screened of cancer to ensure that only those free from cancers to ensure only those free from cancer enters the study. They are then followed for a period to understand the incidence of cancer at the end of the study (Hebel & Robert, 2006). In the study, biases will be corrected by blinding to ensure the final report is not based on information that is biased. The out cone of the results would be measured through undertaking of the various forms of diagnosis and prognosis of the cancer development. List of References Friesen, M. C, 2006, Sensitivity of exposure-response relationships to exposure assessment strategies in retrospective cohort studies,University of British Columbia. Friis, R. H., & Sellers, T. A, 2009, Epidemiology for public health practice, London, Jones & Bartlett Learning. Hebel, J. R., & Robert, J. M, 2006, A study guide to epidemiology and biostatistics, London: Jones & Bartlett Learning. Kang, S, 2007, Statistical methods for case-control and case-cohort studies with possibly correlated failure time data, ProQuest. Riegelman, R. K, 2005, Studying a study and testing a test, how to read the medical evidence. Philadelphia, Lippincott Williams & Wilkins. Read More