OBJECTIVE: To analyse the leprosy case detection rates in Amazonas State, Brazil, by age group from 1980 to 2009.
METHOD: The historical data series of leprosy cases by age group from 1980 to 2009 were fitted as a function of time using Poisson regression models. Relative annual reduction in the detection rate (RAR) by age group was estimated as one minus the exponential of the estimated regression coefficient for time. To compare the regression coefficients, we used their 95% confidence interval.
RESULTS: The relative annual reduction varied from 9% in the age group of 0-4 years to 1% in the age group of 60-69 years. There was a declining trend of the RAR in the younger age groups that disappeared after 29 years of age. The detection rate in people >29 years old declined very little over time, with no statistically significant difference between age groups.
CONCLUSION: Our findings show a reduction in the infection risk in the last 30 years and a birth cohort effect: cohorts born in more recent years faced smaller risks of leprosy infection than older cohorts.
BT - Tropical medicine & international health : TM & IH C1 - http://www.ncbi.nlm.nih.gov/pubmed/22035216?dopt=Abstract C2 - UK CY - Oxford DA - 2012 Feb DO - 10.1111/j.1365-3156.2011.02900.x IS - 2 J2 - Trop. Med. Int. Health LA - eng N2 -OBJECTIVE: To analyse the leprosy case detection rates in Amazonas State, Brazil, by age group from 1980 to 2009.
METHOD: The historical data series of leprosy cases by age group from 1980 to 2009 were fitted as a function of time using Poisson regression models. Relative annual reduction in the detection rate (RAR) by age group was estimated as one minus the exponential of the estimated regression coefficient for time. To compare the regression coefficients, we used their 95% confidence interval.
RESULTS: The relative annual reduction varied from 9% in the age group of 0-4 years to 1% in the age group of 60-69 years. There was a declining trend of the RAR in the younger age groups that disappeared after 29 years of age. The detection rate in people >29 years old declined very little over time, with no statistically significant difference between age groups.
CONCLUSION: Our findings show a reduction in the infection risk in the last 30 years and a birth cohort effect: cohorts born in more recent years faced smaller risks of leprosy infection than older cohorts.
PB - Blackwell Publishing Ltd PP - Oxford PY - 2012 SP - 244 EP - 6 T2 - Tropical medicine & international health : TM & IH TI - Leprosy decline in Amazonas State, Brazil. VL - 17 SN - 1365-3156 ER -