Ageing with Trypanosoma cruzi infection in a community where the transmission has been interrupted: the Bambuí Health and Ageing Study (BHAS).

Background: The prevalence of Chagas' disease is decreasing in Brazil. Due to cohort effect, the disease might remain a public health problem for some time among older individuals. The present burden of Trypanosoma cruzi infection for the elderly living in areas where the transmission has been interrupted has not been studied.
Methods: The prevalence of T. cruzi infection and its association with indicators of health status and health services use were assessed among the elderly living in one of the oldest endemic areas in Brazil (Bambuí, MG). Seropositivity was determined by blood tests (IHA and ELISA) performed in 85.6% of all residents aged 60+ (1496/1742) and in 83.1% of sampled residents aged 5-59 years (1212/1458).
Results: Seropositivity showed a cohort effect, with no cases below 20 years and high prevalence among those aged 60+ years (37.7%). After adjustment for confounders, seropositivity was associated with self-rated health reasonable (OR = 1.43; 95% CI : 1.03-1.98) and bad/very bad (OR = 1.89; 95% CI : 1.30-2.75), staying in bed in past 2 weeks (OR = 1.88; 95% CI : 1.21-2.92), hospitalization in past 12 months (OR = 1.41; 95% CI : 1.05-1.89) and use of 5+ prescribed medications in past 3 months (OR = 1.75; 95% CI : 1.15-2.59).
Implications: Our results are an example of how survival of individuals with past exposure to infectious disease may lead to a different picture of ageing in the developing world. Policy makers need to consider the extra burden imposed by increasing rates of non-infectious disease among the elderly (as observed in Brazil) including the consequences of T. cruzi infection in areas where the infection was widespread in the past.