Epidemiological features of tuberculosis infection in a rural prefecture of Japan from 2007 to 2018

Abstract

This study aimed to investigate the epidemiological features of reported tuberculosis (TB) infections in a western prefecture (Nagasaki Prefecture) from 2007 to 2018, and to identify the high-risk group for TB infection. The characteristics of 12 years of reported TB infections from the Nagasaki Prefectural Informational Center of Infectious Diseases were summarized by median (interquartile range [IQR]) and proportion; the annual TB infections' notification rate regarding sex/age was calculated accordingly. The diagnosis of TB infection was made according to clinic symptoms and laboratory examination. In total, 4364 TB infections were reported in 2007 and 2018, with a median age (IQR) of 74 (55-84) years. The majority of TB infections were male (52.6%, 2297/4364), > 65 years (65.8%, 2869/4364), and indigenous (98.1%, 4276/4364). Among active TB, 66.9% (1833/2740) had pulmonary TB, and 25.3% (694/2740) were diagnosed as extrapulmonary TB. The highest notification rate of TB infection was observed in the elderly male population (> 85 years). The annual notification rate of TB infections ranged between 19.4/and 34.0/100,000 for 12 years. The notification rates of TB infections were high in older people of both sexes, especially in men aged > 85. Therefore, appropriate interventions and health management are essential for TB control in (and with a focus on) the elderly population.