PUBH 6035 Module 2 Assignment 2; Problem Set - Measures of Disease Frequency

Assignment2:ProblemSet:MeasuresofDiseaseFrequencyQUESTION1 Consider a group of 1,000 newborn infants. 100 infants were born with seriousbirth defects and 20 of these 100 died during the first year of life. 90 of the 900remaininginfantswithoutanybirthdefectsalsodied duringthefirst yearoflife. A) Calculate the prevalence of serious defects in this population at the time ofbirth. •=100/1000=0.1/1,000livebirthsor10%ofthepopulationhad seriousbirthdefects B) Calculatetheoverallcumulativeincidenceofmortalityinthispopulation. • -number ofnewcases/numbersofpopulation • -infantsdiesfromdefect =20 • Infants diedwithoutdefects =90=20+90=110 • 110/1000livebirths=11%ofpopulationdiedduetothebirthdefects C) Calculatethecumulativeincidencedifferenceinmortalitybetweeninfantsbornwithserious birth defects andwithout. • Infantsdiedfrombirthdefects=20 • Infants diedwithout birthdefects=90 •= 90-20=70 per1000 personyears D) Stateinwordsyourinterpretationofthecumulativeincidencedifferencecalculated in partc. This isdetermined that 70 infants per 1,000 cases will die from the birth defects in thepopulation.Bysubtractingthe90ofthe 900remaininginfantswithany birthdefectsandsubtractedthemfromthe20 of the infants who diedfromboth defects. Question2: Suppose that you are following a group of children for the development of asthma over a one-year period. You identify 100 children on January 1st, screen them for asthma, and set up amonitoring program to check on their status on a monthly basis. Five children are consideredprevalent cases because they were diagnosed with asthma before January 1st. Ten childrendevelop asthma on March 1st and another ten children develop asthma on July 1st. Another 10children whoremainhealthywere followedfor sixmonthsandthenwere losttofollow-up.Allof the remaining children did not develop asthma and were not lost to follow-up. Follow-upended on December31st. • Whatwastheprevalence ofasthmaonJune1st? • Whatwastheprevalence ofasthma onSeptember 1st? • How many person-months of observation were accrued by this population? • What was the incidence rate of asthma in this population for the one-year period?