| Show An Investigation of the Incidence of Chlamydia trachomatis and Neisseria Gonorrhea in Utah 1997-1999 John Contreras P P Jennifer Lloyd V PH George White Ph SH Abstract This county versus state comparison of chlamydial and gonorrheal infection rates examined whether these diseases were evenly distributed throughout Utahpopulation Expected disease rates were calculated for sex and age-specific groups by county by year and compared to actual disease rates usingstandardized incidence ratio The only significantly elevated rates compared to the state were chlamydial and gonorrheal rates in Salt Lake County for all groups and chlamydial rates in Weber County for certain groups Chlamydia and gonorrhea were not evenly distributed during 1997-1999 infection rates in two counties were higher than expected Introduction In 1999 2220 individuals in Utah were diagnosed with chlamydia trachomatis forrate of 104cases per 100 000 persons There were also 254 individuals diagnosed with Neisseria gonorrhea forrate of 12cases per 100000 persons Utah Department of Health Bureau of Epidemiology In 1999 the national rate of Chlamydia was 254cases per 100 000 persons and the rate for gonorrhea was 1332 cases per 100 000 persons Division of Sexually Transmitted Disease Prevention 2000 Utahrates of chlamydia and gonorrhea have remained well below the national rates and the Healthy People 2000 Objectives for the years 1997-1999 Healthy People 2000 91 Gonorrheal infection rates for these years are below the Healthy People 2010 Objectives Tracking Healthy People 2010 2000 The majority of chlamydial and gonorrheal infections occurred in the following metropolitan counties Davis Salt Lake Utah and Weber Based on anecdotal evidence and observations of the authors it is believed that the morbidity of these diseases is not uniformly distributed throughout Utahpopulation The purpose of this investigation is to compare the rates for individual counties to those of the state aswhole This investigation will compare the rates of chlamydial and gonorrheal infections among persons who are 15-19 20-24 25-29 and 30 years of age from 1997 through 1999 Methods The numbers of chlamydial and gonorrheal infections were obtained from the Utah Department of Health Bureau of Epidemiology STD-MIS Database Utah Department of Health Bureau of Epidemiology The Bureau of Epidemiology is notified of cases of reportable diseases including chlamydial and gonorrheal infections by hospitals laboratories and physicians These infections are reportable according to the State of UtahCommunicable Disease Rule Sections 26130 and 2663 State of Utah Administrative Code Population estimates were obtained from the Utah Department of HealthAction 2000 database Utah Department of Health Action 2000 To calculate an expected rate of disease for each sex and age-specific group the number of cases in the state of Utah minus the number of cases in the county under evaluation was used as the numerator and the population of the state of Utah minus the population of the county under evaluation was used as the denominator The formula used to calculate the expected number of cases is presented in Appendix Aldrich and Griffth 93 combination of three statistical criteria were used to determine if the occurrences of chlamydia and gonorrhea by county were significantly different from what would be expected if the distribution of these diseases was uniformly distributed by population density standardized incidence ratio SIR greater than one 0 confidence interval Cl surrounding the SIR that did ot include one 0 within its confidence imits andstatistical power equal to or greater than 80 percent The statistical formula for the SIR confidence interval 95 percent is presented in Appendix Frumkin and Kantrowitz 1987 power of 80 percent or greater is a3 Digital image 2005 Marriott Library University of Utah Al rights reserved |
