Gender and diagnostic shifts in TB trends: Insights from 15-year data in Northwest China

Background China faces a severe tuberculosis (TB) situation, particularly in Xinjiang. This study analyzed the influence of age, period, and birth cohort on TB incidence trends in the region. Methods Trends in incidence and inflection points were analyzed using a joinpoint regression model (JPR) based on pooled data of pulmonary tuberculosis (PTB) case reports from 2006 to 2020. An age-period-cohort (APC) model based on intrinsic estimation (IE) was used to analyze the impact coefficients, which were transformed into relative risks (RR) to estimate trends. Results From 2006 to 2020, the incidence of TB in Urumqi declined at an average rate of 4% per year, according to JPR. APC analysis model showed the highest age effect at ages 20-24 years (RR = 1.81) and 80-84 years (RR = 2.22). Females aged 85-89 showed a decreasing trend in incidence, while males experienced a sharp increase. The risk of the two diagnostic types was initially the same; bacteriological diagnoses had a higher risk of morbidity (RR = 1.14) compared to clinical diagnoses during 2016-2020. The cohort effect was highest in 1973-1977 (RR = 2.71) and then declined rapidly, particularly in bacteriological diagnosis from 1978 onwards. Conclusions While TB incidence in Urumqi has declined, young adults (20-24) and the elderly (≥70) remain high-risk groups. The effects of gender and diagnosis type varied by age, period, and cohort. These findings help identify at-risk populations and inform targeted interventions.