All this pictures are one question. Lung Cancer & Smoking Case Study Student ove
ID: 2936818 • Letter: A
Question
All this pictures are one question.
Lung Cancer & Smoking Case Study Student over a 4-year period (April 1948 - February 1952). Initially, 20 hospitals, and later more were asked to noify the invesigators of all patients admitted with a new diagnosis of lung cancer. These patients were then interviewed concerning smoking habits, as were controls selected from patients with other disorders primarily non-malignant) who were hospitalized in the same hospitals at the same time. A causal relationship between cigarette smeking and lung cancer was first suspected in the 1920s on the basis of clinical observations. To test this apparent association, numerous epidemiologic studies were undertaken between 1930 and 1960. Two studies were conducted by Richard Doll and Austin Bradford Hill in Great Britain, The first was a case-control study begun in 1947 comparing the smoking habits of lung cancer patients with the smoking habits of other patients. The second was a cohort study begun in 1951 recording causes of death among British physicians in relation to smoking habits. This case study deals first with the case-control study then with the cohort study Data for the cohort study were obtained from the populaton of all physicians listed in the Briish Medical Register who resided in England and Wales as of October 1951, Information about present and past smoking habits was obtained by questionnaire. Infomation about lung cancer came from death cerdficates and oher mortality data recorded during ensuing years. Data for the case-control study were obtained from hospitalized patients in London and vicinityExplanation / Answer
9) Proportion of smoked cases= a/(a+b+c+d)= 1450/2930= 0.4948
Proportion of smoked cases controls = 1345/2930= 0.4590
10) Proportion of smoked cases is slightly higher than Proportion of smoked in controls.
11a) Odds ratio among the cases =a/c= 1450/15= 96.67
11b) Odds ratio among the controls =b/d= 1345/120= 11.21
12) Odds ratio= (a/c)/(b/d)= 96.67/11.21= 8.62
OR of > 1 suggests that the odds of exposure are positively associated with the adverse outcome compared to the odds of not being exposed.
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