Longitudinal Pattern of Cancer Mortality Rates among Iranian Population from 1990 to 2015, Using a Growth Mixture Model

Cancer is among the most important causes of death worldwide. This disease is the third main cause of death in Iran. In the present study, mortality rates of Iranian men and women due to various cancers were analyzed using a database from 1990 to 2015 (in 5-year intervals), available in the Global Burden of Disease (GBD) study. For statistical modeling, Latent Growth Mixture Models (LGMMs) were used to determine the subgroups of cancers, in which cancers within each group had similar trends of mortality rates over the period of study. The LGMM identified 3 classes for both female and male data. For females, most cancers were allocated to the class with a slow increase in cancers mortality over time. Cancers in Class 2, including breast, stomach, trachea, bronchus and lung, colon and rectum, liver, brain, and nervous system, ovarian, and pancreatic had an increasing trend until 2000; then, they reached a fixed trend during 2000-2005, followed by showing an increasing trend once again. In the last class, leukemia showed a decreasing trend of mortality rate over time. For male data, most cancers were allocated to the class with a very slowly increasing trend in mortality rate over time. In both Class 2 (including bladder, brain and nervous system, liver, non-Hodgkin lymphoma, and pancreatic cancers) and Class 3 (including breast, larynx, leukemia, prostate, stomach, trachea, bronchus, and lung cancers), there was an increasing trend of mortality rate over time until 1995 and then it reached an almost stable trend during 1995-2005 followed by an increasing trend once again. Hence, the general status of cancer mortality rates shows an ascending trend. Therefore, it is necessary to provide programs for early detection, screening, preventing, public health program planning, and patient care improvement.