Gender specific trends in both age-adjusted and age specific morbidity and mortality were compared. Trends in rates estimated from events classified according to ICD-9 discharge and death certificate codes were contrasted with those estimated from cases validated by standardized diagnostic algorithms. Data regarding circumstances of death and in-hospital treatment were assessed in relation to potential influences on morbidity and mortality trends. Absolute changes over time and average annual percent change over time were evaluated using linear and log-linear regression regression techniques. Other analytic methods included logistic regression and analysis of variance. Expected annual event rates in men and women were estimated from risk factor data using equations based upon accelerated failure time Weibull models, and the impact of risk factors on mortality rates was assessed by comparing predicted with actual rates.