Question

Breast cancer incidence data and average per capita daily consumption of a wide range of foods for 24 countries were extracted from routinely collected data sources. The relationship between fat consumption and breast cancer is illustrated

200 USA 150 SWI CAN FRA NZ ISR FRG DEN UK AUST. SWE • NOR Annual average incidence per 100 000 pyrs 100 FIN DDR YUG HK ROM • CUBA • SIN JAP SPA • CZE POL HUN 50 200 50 100 150 Total fat intako por caput (a por day)

Identify and describe the following:

a) Type of study (Case-control, Cohort (prospective or retrospective), cross-sectional, ecologic, or experimental.                               

b) Main outcome(s) of interest:                                                                       

c) Main exposure(s) of interest:                                                                     

d) Describe the association between the exposure and outcome according to the results of the graph below:

e) Name the kind of bias related to this kind of study when conclusions are falsely interpreted at the individual level.   

Answer 1

A) cross sectional study - as are taking records from different countries

B) main outcome of interest is breast cancer

C) main exposure of interest is percapita fat consumption

D) exposure and outcome are linearly related. As fat consumption increases outcome of breast cancer increases

E) information bias and selection bias may occur ( sorry, I'm not sure about this)

Answer 2

a) Type of study: Cross-sectional (a type of observational data, where variables are collected at same point of time.)

b) Main outcome of interest: Breast cancer

c) Main exposure of interest: Dietary fat

d) Association: Higher the daily fat consumption in a person, higher the chances of getting breast cancer. There is positive correlation between both variables.

e) Selection Bias