Samuel Kwaku Essien1, Tasha Epp2, Cheryl Waldner2, Wendy Wobeser3, Vernon Hoeppner4. 1. School of Public Health, University of Saskatchewan, Saskatoon, SK, S7N 2Z4, Canada. sam.essien@usask.ca. 2. Western College of Veterinary Medicine, 52 Campus Dr., Saskatoon, SK, S7N 5B4, Canada. 3. Department of Medicine, Queen's University, Botterell Hall 18 Stuart Street, Kingston, ON, K7L 3N6, Canada. 4. Department of Medicine, University of Saskatchewan, 103 Hospital Dr., Saskatoon, SK, S7N 0W8, Canada.
Abstract
OBJECTIVES: To explore tuberculosis (TB) incidence in Canada and the United States from 1953 to 2015. In the most recent decade, the US incidence was lower than that of Canada. Since both countries are high income and have low TB incidence with similar TB surveillance programs, we hypothesized that rates should be similar. METHODS: TB incidence data from 1953 to 2015 were retrieved for both countries. Joinpoint regression was performed to identify change points in the trend, and direct standardization of US rates using Canadian ethnic population distribution was calculated. Adjusted rate and average annual percent change (AAPC) were estimated. RESULTS: Canada rates/100,000 were higher from 1953 to 1974 and similar from 1975 to 1985. This coincided with a change in US case definition in 1975. US rates were higher from 1986 to 1996. HIV/TB coinfection in the USA was 10.2% compared to that of Canada, 1.6%. Rates were similar from 1997 to 2004. Canada rates were again higher from 2005 to 2015. The Canada average AAPC rate in 1975-2015 was lower, - 2.9%, compared to that of the USA, - 4.1%. Foreign-born and Indigenous population proportions were 20.2% and 4.2% for Canada and 12.9% and 1.7% for the USA. The US rate adjusted to the Canada ethnic composition was 4.8 compared to the Canadian rate of 4.7. CONCLUSION: Case definition change and HIV coinfection contributed to the 1980 US rate increase. TB rates decreased in both countries from 1997, but more rapidly in the USA. The Canada proportion of foreign-born and Indigenous populations was higher. When US rates were standardized by Canada ethnic distribution, the national rates were similar. Further exploration of factors contributing to differences between these countries is needed.
OBJECTIVES: To explore tuberculosis (TB) incidence in Canada and the United States from 1953 to 2015. In the most recent decade, the US incidence was lower than that of Canada. Since both countries are high income and have low TB incidence with similar TB surveillance programs, we hypothesized that rates should be similar. METHODS: TB incidence data from 1953 to 2015 were retrieved for both countries. Joinpoint regression was performed to identify change points in the trend, and direct standardization of US rates using Canadian ethnic population distribution was calculated. Adjusted rate and average annual percent change (AAPC) were estimated. RESULTS: Canada rates/100,000 were higher from 1953 to 1974 and similar from 1975 to 1985. This coincided with a change in US case definition in 1975. US rates were higher from 1986 to 1996. HIV/TB coinfection in the USA was 10.2% compared to that of Canada, 1.6%. Rates were similar from 1997 to 2004. Canada rates were again higher from 2005 to 2015. The Canada average AAPC rate in 1975-2015 was lower, - 2.9%, compared to that of the USA, - 4.1%. Foreign-born and Indigenous population proportions were 20.2% and 4.2% for Canada and 12.9% and 1.7% for the USA. The US rate adjusted to the Canada ethnic composition was 4.8 compared to the Canadian rate of 4.7. CONCLUSION: Case definition change and HIV coinfection contributed to the 1980 US rate increase. TB rates decreased in both countries from 1997, but more rapidly in the USA. The Canada proportion of foreign-born and Indigenous populations was higher. When US rates were standardized by Canada ethnic distribution, the national rates were similar. Further exploration of factors contributing to differences between these countries is needed.
Authors: Knut Lönnroth; Giovanni Battista Migliori; Ibrahim Abubakar; Lia D'Ambrosio; Gerard de Vries; Roland Diel; Paul Douglas; Dennis Falzon; Marc-Andre Gaudreau; Delia Goletti; Edilberto R González Ochoa; Philip LoBue; Alberto Matteelli; Howard Njoo; Ivan Solovic; Alistair Story; Tamara Tayeb; Marieke J van der Werf; Diana Weil; Jean-Pierre Zellweger; Mohamed Abdel Aziz; Mohamed R M Al Lawati; Stefano Aliberti; Wouter Arrazola de Oñate; Draurio Barreira; Vineet Bhatia; Francesco Blasi; Amy Bloom; Judith Bruchfeld; Francesco Castelli; Rosella Centis; Daniel Chemtob; Daniela M Cirillo; Alberto Colorado; Andrei Dadu; Ulf R Dahle; Laura De Paoli; Hannah M Dias; Raquel Duarte; Lanfranco Fattorini; Mina Gaga; Haileyesus Getahun; Philippe Glaziou; Lasha Goguadze; Mirtha Del Granado; Walter Haas; Asko Järvinen; Geun-Yong Kwon; Davide Mosca; Payam Nahid; Nobuyuki Nishikiori; Isabel Noguer; Joan O'Donnell; Analita Pace-Asciak; Maria G Pompa; Gilda G Popescu; Carlos Robalo Cordeiro; Karin Rønning; Morten Ruhwald; Jean-Paul Sculier; Aleksandar Simunović; Alison Smith-Palmer; Giovanni Sotgiu; Giorgia Sulis; Carlos A Torres-Duque; Kazunori Umeki; Mukund Uplekar; Catharina van Weezenbeek; Tuula Vasankari; Robert J Vitillo; Constantia Voniatis; Maryse Wanlin; Mario C Raviglione Journal: Eur Respir J Date: 2015-04 Impact factor: 16.671