Two thousand women aged 55 years were given a health check and 100 were found to have high blood pressure. Ten years later, all 2000 women attended a second check and another 300 women had developed...

Two thousand women aged 55 years were given a health check and 100 were found to have high blood pressure. Ten years later, all 2000 women attended a second check and another 300 women had developed high blood pressure

(a) What was the prevalence of high blood pressure in the women (i) at age 55, and (ii) at age 65? (b) How many women were ‘at risk’ of developing high blood pressure at the start of the 10-year period? (c) What was the incidence of high blood pressure in these women? Is this an incidence proportion or an incidence rate? Assume that, on average, each of the 300 women who developed high blood pressure did so half-way through the 10 year follow-up period. (d) Calculate the total number of person-years at risk (of developing high blood pressure) during the 10 years. (e) What was the incidence rate of high blood pressure in these women?