Method for calculating prevalence of disease All new and pre-existing cases during a given time period divided byPopulation during the same time period × 10 n The value of 10 n is usually 1 or 100 for common attributes. The value of 10 nmight be 1,000, 100,000, or even 1,000,000 for rare attributes and for most diseases. EXAMPLE: Calculating Prevalence In a survey of 1,150 women who gave birth in Maine in 2018, a total of 468 reported taking a multivitamin at least 4 times a week during the month before becoming pregnant. Calculate the prevalence of frequent multivitamin use in this group. Numerator = XXX multivitamin users Denominator = XXXX women Calculate the Prevalence = (XXX ⁄ XXXX) × 100 = Method for calculating incidence rate Number of new cases of disease or injury during specified period divided byTime each person was observed, totaled for all persons In 2018, 44,232 new cases of acquired immunodeficiency syndrome (AIDS) were reported in the United States. The estimated mid-year population of the U.S. in 2018 was approximately 290,809,777. Calculate the incidence rate of AIDS in 2003. Numerator = XXXXXnew cases of AIDS Denominator = XXXXXXXXX estimated mid-year population Incidence rate = (XXXXX ⁄ XXXXXXXXX) × 100,000 = XX.XX new cases of AIDS per 100,000 population.