Question

Assume cocaine users suffer from 336 strokes per 10,000 and

non-cocaine users suffer from 33 strokes per 100,000. What is the
percent attributable risk?

Answer 1

The percent attributable risk of strokes for cocaine users compared to non-users is approximately 99%. This was calculated by comparing the incidences of stroke in both populations and using the percent attributable risk formula.

Step-by-step explanation:

To calculate the percent attributable risk (PAR) associated with cocaine use and strokes, you use the following formula:

PAR = [(Incidence in exposed - Incidence in unexposed) / Incidence in exposed] × 100%

First, we need to express both the incidences in the same terms. The incidence for cocaine users is given per 10,000, and for non-cocaine users, it's per 100,000:

• Cocaine users: 336 strokes per 10,000
• Non-cocaine users: 33 strokes per 100,000 (which is equivalent to 3.3 strokes per 10,000 for direct comparison)

Now we calculate the attributable risk:

PAR = [(336 - 3.3) / 336] × 100% = [332.7 / 336] × 100% ≈ 99%

So, the credible percentage of the stroke risk attributable to cocaine use is approximately 99%.