Cancer Stage at Diagnosis, Historical Redlining, and Current Neighborhood Characteristics: Breast, Cervical, Lung, and Colorectal Cancers, Massachusetts, 2001-2015

Abstract

In the 1930s, maps created by the federal Home Owners' Loan Corporation (HOLC) nationalized residential racial segregation via "redlining," whereby HOLC designated and colored in red areas they deemed to be unsuitable for mortgage lending on account of their Black, foreign-born, or low-income residents. We used the recently digitized HOLC redlining maps for 28 municipalities in Massachusetts to analyze Massachusetts Cancer Registry data for late stage at diagnosis for cervical, breast, lung, and colorectal cancer (2001-2015). Multivariable analyses indicated that, net of age, sex/gender, and race/ethnicity, residing in a previously HOLC-redlined area imposed an elevated risk for late stage at diagnosis, even for residents of census tracts with present-day economic and racial privilege, whereas the best historical HOLC grade was not protective for residents of census tracts without such current privilege. For example, a substantially elevated risk of late stage at diagnosis occurred among men with lung cancer residing in currently privileged areas that had been redlined (risk ratio = 1.17, 95% confidence interval: 1.06, 1.29), whereas such risk was attenuated among men residing in census tracts lacking such current privilege (risk ratio = 1.01, 95% confidence interval: 0.94, 1.08). Research on historical redlining as a structural driver of health inequities is warranted.

Keywords: breast cancer; cervical cancer; colorectal cancer; health inequities; historical redlining; lung cancer; residential segregation; stage at diagnosis.

Figure 1

Boxplots of current characteristics (2001–2015) of census tracts in 28 Massachusetts municipalities with Home Owners’ Loan Corporation (HOLC) maps, by HOLC grade in 1937–1938. A) Percentage of persons living below the federal poverty level. Analysis of variance (ANOVA) F statistic (AFS): for all 6 HOLC categories (AFS_all), AFS = 1.31 (P = 0.253); for HOLC categories A–D only (AFS_A–D), AFS = 39.48 (P < 0.001). B) Index of concentration at the extremes (ICE) for race/ethnicity. AFS_all = 4.76 (P = 0.030); AFS_A–D = 14.39 (P < 0.001). C) ICE for income. AFS_all = 0.25 (P = 0.614); AFS_A–D = 55.13 (P < 0.001). D) ICE for race/ethnicity and income. AFS_all = 0.59 (P = 0.442); AFS_A–D = 45.46 (P < 0.001). E) ICE for home ownership. AFS_all = 0.83 (P = 0.362); AFS_A–D = 73.30 (P < 0.001). All tests of statistical significance were 2-sided. Operational definition of HOLC categories (x-axis): A, census tracts whose land area is (100% A or (≥50% A and <100% A)); B, census tracts whose land area is (100% B or (≥50% B and <100% B)); C, census tracts whose land area is (100% C or (≥50% C and <100% C)); D, census tracts whose land area is (100% D or (≥50% D and <100% D)); “mixed,” mixed census tracts with ≥50% of land area assigned HOLC grades but with no HOLC grade accounting for ≥50% of the total land area; “no grade assigned,” census tracts whose land area is ≥50% unknown.

Figure 2

Proportions of persons with late cancer stage at diagnosis (Massachusetts Cancer Registry data) in 28 Massachusetts municipalities with Home Owners’ Loan Corporation (HOLC) rankings, by 1930s HOLC ranking and current census-tract index of concentration at the extremes (ICE) for terciles (T) of racialized economic segregation, 2001–2015. Proportions were indirectly standardized to the overall distribution of age, sex/gender, and race/ethnicity in the sample. A) Breast cancer; B) cervical cancer; C) colorectal cancer; D) lung cancer. Sex/gender and ICE tercile: △ female and T1; ▲ female and T2 + T3; □ male and T1; ■ male and T2 + T3; ○ total and T1; total and T2 + T3. Operational definition of HOLC categories (x-axis): A + B, census tracts whose land area is ((100% A or (≥50% A and <100% A)) or (100% B or (≥50% B and <100% B))); C, census tracts whose land area is (100% C or (≥50% C and <100% C)); D, census tracts whose land area is 100% D or (≥50% D and <100% D). T1, tercile 1 (best); T2, tercile 2; T3, tercile 3 (worst).