Topic1_Exercises.pdf

Exercises: Exercise 1.1 (causality): The figure below displays graphs for smoking and lung cancer. Incidence per 100.000 per year Smokers (%) Year Figure 1. The figure shows the change in the proportion...

Exercises: Exercise 1.1 (causality): The figure below displays graphs for smoking and lung cancer. Incidence per 100.000 per year Smokers (%) Year Figure 1. The figure shows the change in the proportion of male smokers in Denmark (dotted line) and the change in the incidence rate of lung cancer in males in Denmark (solid line). 1) Describe the figure and the curves. 2) Which hypothesis could be made based on the figure? What is the exposure and what is the outcome? 3) Based on the curves, can we then conclude that there is a causal relation between smoking and lung cancer? 4) How would you explore the hypothesis further? Exercise 1.2 (causality): The figure below displays the number of Nobel laureates per 10 million population per country and the yearly consumption of chocolate per country (taken from New England Journal of Medicine, 2012 Oct 18; 367(16):1562-4). 1) Describe the figure. 2) Make a hypothesis based on the figure. 3) How would you explore the hypothesis further? Exercise 1.3 (study designs): A group of epidemiologists wanted to investigate the potential association between smoking habits and the presence of human papilloma virus (HPV). In their study 10,000 women were asked about their present smoking habits and a sample was taken from their cervix. DNA from the cervix sample was analysed for the presence of HPV. The following data was obtained: +HPV -HPV Total Smoker 111 430 541 Non-smoker 1139 8320 9459 Total 1250 8750 10000 1) Which study design was used here? 2) Which measures of frequency and association are often used for this study design? Exercise 1.4 (study designs): In a study, epidemiologists interviewed women about their past drinking habits. Two groups of women were interviewed: 1,000 women with a breast cancer diagnosis and 1,000 women of similar age and socioeconomic status with no cancer diagnosis. The following data was obtained: Drinking habits Breast cancer Yes No Heavy drinkers 345 248 Moderate drinkers/never drinkers 655 752 1) Which study design was used here? 2) Which measures of frequency and association are often used for this study design? Exercise 1.5 (study designs): In1980, 88,000 nurses were interviewed about their food habits and followed for the next 16 years with respect to development of breast cancer. Based on their information on food habits their intake of vitamin D was calculated. The association between vitamin D intake and cancer was investigated and the results are shown below. 1) Which study design was used here? 2) Which measures of frequency and association are often used for this study design?