[Chickenpox-related mortality trends in the state of São Paulo, Brazil, 1985-2004: a multiple cause approach].

Objective: To study mortality trends related to chickenpox, as either the underlying or associated cause-of-death (recorded in any field of the medical section of the death certificate), in São Paulo, Brazil.

Methods: Mortality data for 1985-2004 were obtained from the multiple cause-of-death database maintained by the São Paulo State Data Analysis System (SEADE). Causes-of-death were processed using the Multiple-Causes-of-Death Tabulator.

Results: During this 20-year period, chickenpox was identified as the underlying cause-of-death in 1 037 deaths and an associated cause in 150. The mortality coefficients were higher for chickenpox as the underlying, as opposed to the associated cause, and these declined in the analyzed period; whereas a slight increase was observed in mortality due to chickenpox as an associated cause. Seventy-six percent of the deaths were of children under 10 years of age, with the highest incidence among those under 1 year. Most deaths occurred from July to January (86.8% of 1 187 deaths), with a peak in October. In the state's capital city, the mortality coefficients for chickenpox as underlying cause and as associated cause were 47% and 50% higher, respectively, than in the rest of the state. Where chickenpox was identified as the underlying cause, pneumonias and septicemias were the major associated causes; where it was the associated cause, AIDS or neoplasia were most often the underlying cause.

Conclusions: Although chickenpox as the underlying cause-of-death has declined, the present study indicates that certain groups are at risk of chickenpox-related mortality, namely children 1-4 years of age and individuals with AIDS or neoplasia.