A small cohort study consisting of 10 women over the age of 50 with low bone den
ID: 3353495 • Letter: A
Question
A small cohort study consisting of 10 women over the age of 50 with low bone density were followed for 10 months. Below are the clinical outcomes per patient per month. Lost to follow-up ath t to follow-up Osteoporotic Fracture 10 a) What is the prevalence of osteoporotic fractures at 7 months assuming once a woman develops a fracture, she continues to have it for the remainder of the study period? (Round to 2 decimal points.) (2 pts) a. 0.1 b. 0.2 C. 0.3 d. 0.4 b) What is the cumulative incidence at 10 months? (Round to 2 decimal points.) (2 pts) a. 0.2 b. 0.4 C. 0.6 d. 0.8Explanation / Answer
A) Prevalence = ( No. of animals with situation at a given time / Total no. of animals in that time period )
At 7 months, numerator = 2, denominator = 10
=> Prevalence at 7 months = 2/10 = 0.2 (Answer: b)
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B) Cumulative incidence = (No, of new cases in the given time period / No. of total people without situation at start of time period) = 4/10 = 0.4 [Answer: b]
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C) Incidence rate = ( Total number of new cases of situation during a time period / Total population-time observed ) *(person months asked for)
= 4 / (10+8+6+4+6+5+10+10+6+5)*10,000 = (4/70)*(10000) = 571.4 [Answer: a]