Trends and age-period-cohort effects on incidence and mortality of asthma in Sichuan Province, China, 1990-2019

Abstract

Background: The provinces in western China have undergone rapid urbanization and industrialization, particularly since the Chinese government launched the Great Western Development Strategy in 2000. We examined the time trends and contributions of age, period, and cohort effects to asthma incidence and mortality in Sichuan Province, a populous province in western China, from 1990 to 2019.

Methods: The data of Sichuan Province from 1990 to 2019 were extracted from the Global Burden of Disease study 2019. Trends and average annual percentage change were estimated using joinpoint regression. Age, period, and cohort effects were estimated using an age-period-cohort model with the intrinsic estimator method.

Results: In the latest period (2015-2019), the highest incidence of asthma was 2004.49/100,000 in children aged < 5 years, and the highest mortality rate was 22.04/100,000 for elderly people aged > 80 years. Age-standardized rates generally remained stable (95% confidence interval [CI] - 0.21, 0.11) for incidence and declined by 4.74% (95% CI - 5.09, - 4.39) for mortality over the last 30 years. After controlling for other effects, the age effect on asthma showed that the incidence rate ratio (RR) was highest in the < 5 years age group, and the mortality RR was highest in the > 80 years age group. The period effect on incidence and mortality decreased from 1990 to 2019, respectively. A cohort effect was found the incidence RR increased slowly from the early birth cohorts to the later birth cohorts, especially after the 2005 birth cohort, whereas the mortality RR continued to decline.

Conclusions: There was a significant effect of older age on the asthma mortality rate over the last 30 years, and the incidence rate in children aged < 5 years increased. The relative risk of asthma incidence in the later birth cohorts increased. Effective preventive measures and public health policies should be to protect children and elderly people from potentially harmful chronic diseases.

Keywords: Age-period-cohort effect; Asthma; Incidence; Mortality; Sichuan Province.