Breast Cancer Incidence Patterns Among California Hispanic Women: Differences by Nativity and Residence in an Enclave

Background: Breast cancer incidence is higher in U.S.-born Hispanic women than foreign-born Hispanics, but no studies have examined how these rates have changed over time. To better inform cancer control efforts, we examined incidence trends by nativity and incidence patterns by neighborhood socioeconomic status (SES) and Hispanic enclave (neighborhoods with high proportions of Hispanics or Hispanic immigrants).

Methods: Information about all Hispanic women diagnosed with invasive breast cancer between 1988 and 2004 was obtained from the California Cancer Registry. Nativity was imputed from Social Security number for the 27% of cases with missing birthplace information. Neighborhood variables were developed from Census data.

Results: From 1988 to 2004, incidence rates for U.S.-born Hispanics were parallel but lower than those of non-Hispanic whites, showing an annual 6% decline from 2002 to 2004. Foreign-born Hispanics had an annual 4% increase in incidence rates from 1995 to 1998 and a 1.4% decline thereafter. Rates were 38% higher for U.S.- than foreign-born Hispanics, with elevations more pronounced for localized than regional/distant disease, and for women>50 years of age. Residence in higher SES and lower Hispanic enclave neighborhoods were independently associated with higher incidence, with Hispanic enclave having a stronger association than SES.

Conclusions: Compared with foreign-born, U.S.-born Hispanic women in California had higher prevalence of breast cancer risk factors, suggesting that incidence patterns largely reflect these differences in risk factors.

Impact: Further research is needed to separate the effects of individual- and neighborhood-level factors that affect incidence in this large and growing population.