Question

Suppose in January 2006 you conducted a study in a subsidized housing community in the Boerum Hill section of Brooklyn, NY. You enrolled 1000 residents in your study and checked on their tuberculosis (TB) status on a monthly basis. At the start of your study on January 1^st, screening of the entire study population revealed that 25 of the healthy residents were immigrants who were vaccinated for TB and so were not at risk. Another 45 residents already had existing cases of TB on January 1^st. On March 1^st, 7 residents developed TB and 20 others were lost to follow-up (LTFU). On April 1^st, 5 more residents developed TB. On May 1^st, 32 residents refused to participate any further, thus they were withdrawn (LTFU). On July 1^st, 5 additional residents developed TB. On August 1^st, 10 healthy residents moved away from NYC and were LTFU. On September 1^st, 9 residents developed TB. On October 1^st, 11 of the residents who had existing TB on January 1^st died from their disease. On November 1^st, 1 resident developed TB. The study ended on December 31, 2006. Assume that once a person gets TB, she has it for the duration of the study, and assume that all remaining residents stayed healthy and were not LTFU.

1. Calculate and interpret the prevalence (%) of TB in the screened community on January 1^st.
2. Calculate and interpret the cumulative incidence (%) of TB over the year.

Answer 1

Solution :

Given that

To Calculate and interpret.