The decrease in stomach cancer mortality was not because of specific interventions, and is likely that different countries follow a similar model of variation. Here, we aimed to identify model-based patterns in the time trends of stomach cancer mortality worldwide. Stomach cancer mortality rates were retrieved for 62 countries from the WHO mortality database. Sex-specific mixed models were used to describe time trends in age-standardized rates between 1980 and 2010 (age group 35–74 years; World standard population). Three patterns, similar for men and women, were identified through model-based clustering. Pattern 1 presented the highest mortality rates in 1980 (median: men, 81.5/100 000; women, 34.4/100 000) and pattern 3 the lowest ones (median: men, 24.4/100 000; women, 12.4/100 000). The decrease in mortality rates was greater in 1980–1995 than during 1996–2010. Assuming that the patterns characterized by the highest rates precede temporally those with lower mortality, the overlap of model predictions supports a 20-year lag between adjacent patterns. We propose a model for the variation in stomach cancer mortality with three stages that develop sequentially through a period of ∼70 years. The countries with the lowest mortality had the highest proportional decrease in mortality rates.
aDepartment of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School
bInstitute of Public Health, University of Porto (ISPUP), Porto, Portugal
cDepartment of Epidemiology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri
dDepartment of Medical Sciences and Public Health, University of Milan, Milan, Italy
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Correspondence to Carlo La Vecchia, MD, Department of Epidemiology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Via Giuseppe La Masa 19, 20156 Milan, Italy Tel: +39 02 39014 527; fax: +39 02 33200 231; e-mail: email@example.com
Received May 31, 2013
Accepted June 25, 2013