Question

Researchers conducted a cohort study of the association between air pollution and asthma. The

rate ratio was 8.0, when comparing those exposed to high levels of air pollution with those

exposed to low levels of air pollution. Which of the following issues should the researchers

consider when making their study conclusions and when thinking about causality? Choose all

that apply and explain your choice.

a) The rate ratio of 8.0 indicates a strong association, which lends support for causality

b) Strong confounding may actually be causing the strong association seen

c) Other studies of the same exposure—health outcome association reported rate ratios in the

range of 1.5-3.0, less than the rate ratio of 8.0 seen in this study

d) The temporal sequence of the exposure and outcome should be known in order to draw

accurate conclusion.

Answer 1

a) the rate ratio of 8.0 indicates a strong association. Exposure to high level or level of air pollution causes health problems especially respiratory problems. Causality for the strong association bring health problems even the air has the lower dust particles. Particulate matter size at 2.5 micro meter or lower than 2.5 cause asthma and other health problems.

b) strong confounding causes association between short term exposure of air pollution and brings some health problems. Ex:Individual lifestyle factors like smoking

d) exposure to air pollution and outcome must be known to come for a conclusion. Short term and long term exposure causes health problems even to the low level of air pollution. Normally particulate matter size 10 micro meter and 2.5 micro meter cause respiratory problems. Air pollution will be higher road side and rush hour area morning and evening. At night and before early morning the level of air pollution will be decreased so the exposure of those time may reduce the risk factors.