1. Do Latinas who live in ethnic enclaves have better or worse survival?
Analysis of cancer registry data from California and Texas
Salma Shariff-Marco, PhD, MPH
NAACR/IACR Combined Annual Meeting, June 11, 2019

2. Many Latinx live in ethnic enclaves
Latinx comprise <20% of the total US population; those in metropolitan areas live in neighborhoods where 45% of their neighbors are also Latinx 
Ethnic enclaves are culturally distinct neighborhoods with high concentrations of:
Individuals of same ethnic origin
High linguistic isolation
Large share of recent immigrants
Ethnic specific businesses and resources
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3. Ethnic enclaves and cancer survival?
Cancer is the leading cause of death for Latinas, with breast cancer as most common cancer type and leading cause of cancer death
Is breast cancer survival better or worse for Latinas living in enclaves?

4. Methods vary dramatically across studies & so do results
Measures
Analysis
Covariates
Models
Geographies
Findings
Only 2/6 studies use the same ethnic enclave exposure variable
The remaining 4 used different measures: % Latinx, location quotient, isolation segregation, local exposure index
Enclave/segregation measured continuously, quintiles, low vs. high
All studies applied different conceptual/analytic models
SES conceptualized as independent covariate or moderator
3/6 studies included foreign birthplace
4/6 studies used multilevel models
2 studies in TX, 2 studies in CA, 1 in Milwaukee, 1 in SEER registries

5. Objective
Conduct a parallel analysis in California and Texas to test the association of Latinx enclave residence and survival among women with breast cancer while adjusting for nativity and neighborhood SES

6. Methods
CA and TX cancer registry data & 2000 U.S. Census data (census tract)
Inclusion: Latina, ≥18 years, first invasive primary breast cancer (vital status follow-up through December 2014)
Exclusion: Missing diagnosis/death month, low geocoding certainty, missing address, autopsy/death certificate diagnosis
Outcome:
All cause mortality
Breast cancer specific mortality
Cox proportional hazards regression, adjusted for clustering by census tract

7. Latinx enclave & neighborhood SES
Latinx enclave index: linguistically isolated, linguistically isolated who speak Spanish, spoke limited English, Spanish speaking who spoke limited English, recent immigrants, Latinx, and foreign-born
SES index: education, household income, poverty level, working class, unemployed, median rent, median housing value
SES index: education, household income, poverty level, working class, unemployed, median rent, median housing value
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8. Maps here Latinx Enclave
This map shows the census tracts that we identified as ethnic enclaves in CA and in TX based on state-specific quintiles (q4+q5)
2000 Census Tracts, state-specific quintiles 4 and 5 defined enclaves

9. Percent after Imputation
Imputing nativity
Percent
Total N
US-born
Foreign born
Missing
California
23,281
33.8
43.9
22.3
Texas
15,577
38.3
17.6
44.1
Percent after Imputation
Total N
US-born
Foreign born
California
23,281
54.2
45.8
Texas
15,577
75.6
24.4
Logistic regression multiple imputation for missing nativity, restricted to those with no missing covariates:
Year dx, age, stage, grade, histology, tumor size (missing set to zero & tumor size missing indicator variable included), reporting source, case class, microscopic confirmation, cause of death/vital status, survival time
Census tract certainty, % poverty, income, unemployment, working class, gross rental value, home value, foreign born, recent immigrant, language isolation speaking Spanish, limited English; Hispanic enclave index, SES index
Prior to imputation: We had 22% and 44% breast cancer cases diagnosed between missing nativity, 33% and 38% US born, 43% and 17% foreign-born
To impute missing nativity in the registry data, we used logistic regression multiple imputation. Our analytic sample were restricted to case that had no missing covariates. We included both individual and neighborhood level data.
After imputation, 54% of cases are classified as US born, with 46% foreign-born; and in TX 76% are US-born and 24% are foreign-born

10. Distributions of Latinx enclave & nSES by nativity
California
Texas
California
Texas
Overall, after our imputation here’s what we see about distribution:
Foreign-born vs. US born women are more likely to live in Hispanic enclaves- with a much larger percentage of FB women living in the highest quintile of enclave score.
Foreign-born women are less likely to live in high SES neighborhoods when compared to US born women.

11. All Cause Mortality

12. Foreign born (vs. US born) Latinas have worse survival
Latinas residing in less (vs. most) ethnically distinct neighborhoods have worse survival
Latinas residing in lower (vs. higher) SES neighborhoods have worse survival
These are the independent associations of nativity, residence in enclave and nSES and all cause mortality for Ca (shown in pink) and Tx (shown in yellow), i.e., all variables in the same model, and adjusted for XX
Worse survival is observed for
--foreign-born vs. US born
--residing in non-enclaves vs. enclaves
--lower SES vs. higher SES
We see that findings across the states are very similar

13. Breast Cancer-Specific Mortality

14. Foreign born (vs. US born) Latinas have worse survival
Latinas residing in less (vs. most) ethnically distinct neighborhoods have worse survival
Latinas residing in lower (vs. higher) SES neighborhoods have worse survival
Similarly, we see worse survival for breast cancer-specific mortality for
--foreign-born vs. US born
--residing in non-enclaves vs. enclaves
--lower SES vs. higher SES
Note wider confidence intervals? And less clear pattern in Tx??
Not consistent across quintiles, effect sizes are not as big in Tx

15. Interactions: ethnic enclave & nSES

16. All cause mortality
Breast cancer specific mortality
Latinas residing in high SES neighborhoods, regardless of enclave status had improved survival; those in non-enclave and low SES neighborhoods had worse survival.

17. Conclusions & next steps
Key findings
Worse survival
residing in less ethnically distinct or lower SES neighborhoods
Foreign born
Improved survival
Low SES, ethnic enclave
Different methods may drive inconsistencies in the literature
Future studies across diverse states
Parallel analyses and pooled analyses
Validation of multiple imputation of nativity
Key findings:
--Hispanic enclave residence is associated with improved survival
--lower NSES is associated with worse survival
--foreign-born is associated with worse survival
Findings were similar across Ca and Tx when the same methods and measures are applied, suggesting that different methods may be driving inconsistencies in the literature
Further analyses looking at other regions of the US with high Latina populations should be considered for replicating these findings
Different methods
Measures & categorizations of ethnic residential distribution
Inclusion of nativity, different imputation methods
Different measures of N-SES
Different analytic strategies, regression models

18. Acknowledgements Sandi Pruitt Hannah Fullington Alison Canchola
Anupama Vasudevan
Lei Xuan
Amy E. Hughes
Texas Cancer Registry
Alison Canchola
Scarlett Lin Gomez
Jennifer Jain
California Cancer Registry
Funding: NCI SEER Program HHSN I