Liu S, Manson EJ, Stampfer MJ, Hu FB et al. A prospective study of whole-grain intake and risk of type II diabetes Mellitus in US Women. American Journal of Public Health, 2000; 90:9.
Make sure your answers are no more than 100 words!!
(a) What was the study design and what are the advantages of using this design for their research questions? [2 mark]
(b) Compute the crude incidence rates of diabetes among this group of women [4 marks]
(c) Table 2 presents the adjusted relative risk of type II diabetes according to quintiles of Total Grain consumption (first 5 lines) relative to the 1st quintile (the lowest consumption as a reference). Calculate the unadjusted (crude, quintile –specific) incidence rate of diabetes by exposure to Total Grain and the crude relative risk (RR) of each quintile, in comparison to the first quintile. Comment in your own words whether any pattern of association between Total Grain consumption and Diabetes can be observed from the unadjusted crude RR [4 marks]
(d) In Table 2 model 2 (multivariables adjustment) of Whole Grain showed the RR of each quintile (increased consumption) relative to the lowest 1st.
What is the pattern of the association? [2 marks]
(e) Why the authors adjusted their analysis for physical activity, smoking alcohol intake and family history. You need to back up your argument with evidence from the data presented in Table 1.[4 marks]
(f) What is the main possible bias in this study? Provide arguments for your answer and how it will affect the estimates. [4 marks]