Age-related crossover in XXXX incidence rates between black and white ethnic groups.

@entity1 @entity5 @entity0
BACKGROUND: Although @entity0 incidence is higher in black @entity1 than in white @entity1 among @entity1 younger than 40 years, the reverse is true among those aged 40 years or older. This crossover in incidence rates between black and white ethnic groups has been well described, has not been completely understood, and has been viewed as an artifact. METHODS: To quantify this incidence rate crossover, we examined data for 440 653 @entity1 with @entity0 from the National @entity5 Institute's Surveillance, Epidemiology, and End Results database from January 1, 1975, through December 31, 2004. Data on invasive female @entity0 were stratified by race, age at diagnosis, year of diagnosis, and @entity5 characteristics. Standard descriptive analyses were supplemented with Poisson regression models, age-period-cohort models, and two-component mixture models. All statistical tests were two-sided. RESULTS: We observed qualitative (ie, crossing or reversing) interactions between age and race. That is, age-specific incidence rates overall (expressed as number of @entity0 per 100 000 @entity1 -years) were higher among black @entity1 (15.5) than among white @entity1 (13.1) younger than 40 years (difference = 2.4, 95% confidence interval [CI] = 2.4 to 2.4), and then, age-specific rates crossed with rates higher among white @entity1 (281.3) than among black @entity1 (239.5) aged 40 years or older (difference = 41.8, 95% CI = 41.7 to 41.9). The black-to-white incidence rate crossover was observed for all @entity5 characteristics assessed, although the crossover occurred at earlier ages of diagnosis for @entity5 characteristics than for high-risk @entity5 characteristics. The incidence rate crossover between ethnic groups was robust (ie, reliable and reproducible) to adjustment for calendar period and birth cohort effects in age-period-cohort models (P < .001 for difference by race). CONCLUSION: Although this ecologic study cannot determine the individual-level factors responsible for the racial crossover in vital rates, it confirms that the age-related crossover in @entity0 incidence rates between black and white ethnic groups is a robust age-specific effect that is independent of period and cohort effects.
