Can someone please check this for me to see if I am on the right track thanks?
In a population-based cohort study, an entire community was interviewed regarding smoking habits and then followed for one year. All lung cancer deaths were ascertained and the following data were available:
•Fifteen (15) lung cancer deaths occurred among 24,500 smokers
•Two (2) lung cancer deaths occurred among 10,500 non-smokers
Calculate the following and interpret your results in each case.
1.Calculate the proper measure of association of smoking and lung cancer.
The relative risk is used to measure the association of smoking and lung cancer.
Using the Rater Ratio to estimate the RR
= 15/100000 =7.5
2/100000
Relative Risk=1
The relative risk is greater than 1 which shows an association between exposure and disease and there is an exposure between smoking and lung cancer.
2.Calculate the population risk difference.
Risk Difference = AR = I of smoker – I of non- smoker
Smoke Lung Cancer Total
Yes No
Yes 15 24,500 24,515
No 2 10,500 10,502
I of smoker
=15/24515
=0.000619
=6.119/100,000
I of non smoker = 2/10502
= 0.0001904
=1.904/100,000
AR difference =6.1-1.9/100000 =4.2/100000
Among non smokers6.1 /10000 incidence case of lung cancer that occur are attributed to the fact that these people smoke.
Among Smokers 6.1/10000 incidence of Lung Cancer that occur could be prevented if smoking was eliminated.
3. Calculate the population attributable risk for smoking and lung cancer.
Population attributable risk measures the potential impact of control measures in a population, and is relevant to decisions in public health.
Population attributable risk = attributable risk x prevalence of exposure to risk factor in population
PAR = I of total population – I of
Smoke Lung Cancer Total
Yes No
Yes 15 24,500 24,515
No 2 10,500 10,502
Total 17 35,000 35,017
I of total population= 17/ 100000
= 0.00017
=17/100000
I of non smoker= 2/10502
= 0.00019044
=1.904/100000
PAR = (17-1.94)/100000
= 15.06
15.06 of the 17/10000 incidence of the Lung Cancer are attributed to smoking
15.06 of the 17/ cases of lung cancer that occur could be prevented from not smoking
You are on the right track with your calculations and interpretations. Here is a summary of your results.
1. Measure of association: You correctly identified the relative risk as the proper measure of association for smoking and lung cancer. By using the rate ratio, you calculated a relative risk of 7.5, which is greater than 1. This indicates a positive association between smoking and lung cancer.
2. Population risk difference: You calculated the incidence rate for smokers and non-smokers and then subtracted the two to find the risk difference. Your calculation of 4.2 per 100,000 indicates that among non-smokers, 4.2 cases of lung cancer out of every 100,000 can be attributed to smoking. Similarly, among smokers, 4.2 cases out of every 100,000 could be prevented if smoking was eliminated.
3. Population attributable risk: You correctly identified that population attributable risk measures the potential impact of control measures in a population. By subtracting the incidence rate of non-smokers from the total population, you found an incidence rate of 15.06 per 100,000 that can be attributed to smoking. This means that 15.06 out of every 100,000 cases of lung cancer can be attributed to smoking, and these cases could be prevented by eliminating smoking.
Overall, your calculations and interpretations are correct based on the data provided. Keep up the good work!