# Analysis of reported incidence of chronic hepatitis B in Chaoyang District, Beijing during 2005–2022 with age-period-cohort model

## TL;DR

This study analyzed chronic hepatitis B trends in Chaoyang District from 2005 to 2022, finding a decline followed by stabilization, with distinct age, period, and cohort effects.

## Contribution

The study applied an age-period-cohort model to identify distinct demographic effects on chronic hepatitis B incidence in a specific urban area.

## Key findings

- Reported incidence of chronic hepatitis B declined from 49.58/100,000 to 8.58/100,000 between 2005 and 2022.
- Age, period, and cohort effects showed distinct patterns, with higher risks in males aged 25–29 and 75–79, and females born in 1966–1970.
- The age-period-cohort model with intrinsic estimator showed better fit than conventional two-factor models.

## Abstract

The study aimed to describe the trend of chronic hepatitis B among the population in Chaoyang District from 2005 to 2022 and explore the effects of age, period, and cohort factors on the incidence risk.

Incidence rates of chronic hepatitis B were collected from the national infectious disease reporting and information management system. Descriptive epidemiological methods were employed to characterize the incidence of chronic hepatitis B from 2005 to 2022. Trends in chronic hepatitis B were analyzed using an age-period-cohort model. The effects of age, period, and cohort on chronic hepatitis B incidence were estimated using the Intrinsic Estimator operator. Model goodness of fit was assessed by introducing variance, AIC, and BIC, comparing the established model with conventional two-factor models.

From 2005 to 2022, the reported incidence of chronic hepatitis B in Chaoyang District showed a gradual decrease followed by stabilization, declining from 49.58/100,000 to 8.58/100,000 overall, from 63.36/100,000 to 11.69/100,000 in males, and from 35.15/100,000 to 5.55/100,000 in females. The age effect coefficient for males with chronic hepatitis B increased initially and then decreased with age, whereas for females, it decreased initially and then increased with age. The period effect on chronic hepatitis B incidence risk in both genders initially decreased and then increased over time. The cohort effect coefficient for males exhibited a pattern of decrease, increase, and then decrease, whereas for females, it generally increased and then decreased. The APC model constructed with the intrinsic estimator demonstrated the best goodness of fit, as indicated by lower variance, AIC, and BIC compared to conventional two-factor models.

The reported incidence of chronic hepatitis B in Chaoyang District from 2005 to 2022 declined and stabilizing after 2013. We found distinct age, period, and cohort effects on the incidence, with higher risks observed in males aged 25–29 and 75–79, and females born in 1966–1970. These findings highlight the importance of targeted surveillance, expanded screening, and improved diagnosis and treatment rates to reduce the long-term chronic hepatitis B burden.