Age transition of tuberculosis incidence and mortality in Brazil

Abstract

ObjectiveBefore the Aids pandemic, demographic transition and control programs prompted a shift in the age of incidence of tuberculosis from adults to older people in many countries. The objective of the study is to evaluate this transition in Brazil. Methods Tuberculosis incidence and mortality data from the Ministry of Health and population data from the Brazilian Bureau of Statistics were used to calculate age-specific incidence and mortality rates and medians. Results Among reported cases, the proportion of older people increased from 10.5% to 12% and the median age from 38 to 41 years between the period of 1986 and 1996. The smallest decrease in the incidence rate occurred in the 30-49 and 60+ age groups. The median age of death increased from 53 to 55 years between 1980 and 1996. The general decline in mortality rates from 1986 to 1991 became less evident in the 30+ age group during the period of 1991 to 1996. A direct correlation between age and mortality rates was observed. The largest proportion of bacteriologically unconfirmed cases occurred in older individuals. ConclusionsThe incidence of tuberculosis has begun to shift to the older population. This shift results from the decline in the annual risk of infection as well as the demographic transition. An increase in reactivation tuberculosis in older people is expected, since this population will grow from 5% to 14% of the Brazilian population over the next 50 years. A progressive reduction in HIV-related cases in adults will most likely occur. The difficulty in diagnosing tuberculosis in old age leads to increased mortality. Resumo

Tuberculosis: a study of 111 cases in an area of high prevalence in the extreme south of Brazil

“…These data corroborate the observation that tuberculosis is a disease that affects the individual in the most productive period of his/her life [1]. However, recent studies show a dislocation of tuberculosis incidence from adults in general to the elderly [8,9]. The observed higher incidence of whites in relation to non-whites may be a consequence of the profile of the population of this region and not to a racial predisposition toward tuberculosis.…”

Time series of tuberculosis mortality in Brazil (1980-2001)

“…The significant presence of Tb mortality in the elderly could be attributed to the weakness of health care services, as previously observed (13)(14) . The…”

Tendência da mortalidade por tuberculose no Brasil, 1980 a 2004

“…These may be: (relative and absolute) growing elderly population due to reduced early mortality and increased life expectancy;*** the fact that elderly have lived through times where TB transmission was much higher associated to potential cumulative infection; increased risk of developing TB among elderly due to age-specifi c immunodefi ciency; and greater likelihood of atypical TB presentations in elderly and association with other diseases, which result in delayed diagnosis and prevent early treatment as well as higher fatality. 7 Alternatively, reduction in the absolute number of cases, proportional mortality and mortality rates in children can be explained by several factors such as reduced TB incidence in adult population especially the highly contagious bacillary pulmonary form since affected adults used to be the main source of infection for children. These fi ndings are also supported by progressively increased BCG vaccine coverage in Brazil in the last two decades, reaching almost 100% over the last 10 years.…”