Background
Methods
Cohort data
Definition of immigrant groups
Ascertainment of breast cancer diagnoses
Ascertainment of breast cancer subtypes
Statistical methods
Additional analyses
Results
Non-immigrants | Immigrants | ||||||
---|---|---|---|---|---|---|---|
Non-immigrants | High-income | Eastern Europe | Middle East | Sub-Saharan Africa | South Asia | South East Asia | |
Total population | |||||||
Mean age (SD) at immigration | N/A | 26.2 (12.4) | 30.0 (13.3) | 24.2 (14.1) | 23.3 (12.4) | 25.0 (14.2) | 27.4 (10.9) |
Mean year (SD) of immigration | N/A | 1995 (17) | 2005 (10) | 2003 (9) | 2006 (8) | 2000 (12) | 2004 (10) |
Education (% tertiary)* | 14.1 | 47.5 | 45.9 | 34.2 | 20.7 | 32.5 | 59.5 |
Income (% lowest quintile)* | 14.0 | 31.7 | 41.6 | 62.2 | 75.4 | 44.3 | 39.3 |
Cases only | |||||||
Mean age (SD) when diagnosed | 62.2 (14.2) | 60.9 (13.6) | 51.8 (12.3) | 49.1 (11.8) | 44.8 (11.2) | 51.9 (12.3) | 48.1 (10.2) |
Mean time (SD) from immigration to diagnosis, years | N/A | 30.4 (14.9) | 14.8 (11.9) | 13.3 (8.8) | 14.5 (12.4) | 19.9 (10.7) | 16.1 (10.6) |
Tumor grade (% high grade 3 or 4) | 16.0 | 16.2 | 19.3 | 21.6 | 19.1 | 21.1 | 21.1 |
Distribution of breast cancer subtypes
Age-standardized rates within subtypes
Age-adjusted incidence rate ratios
Age 20–75 | Age 20–49 | |||
---|---|---|---|---|
Cases/PYR | IRR (95% CI) | Cases/PYR | IRR (95% CI) | |
All subtypes | ||||
Non-immigrants | 21,682/14608517 | 1.00 (ref) | 4750/8335077 | 1.00 (ref) |
High-income | 675/477618 | 1.07 (0.99–1.16) | 154/305153 | 0.94 (0.80–1.10) |
Eastern Europe | 417/593550 | 0.85 (0.77–0.93) | 195/486627 | 0.90 (0.78–1.04) |
Middle East | 136/176786 | 0.93 (0.79–1.10) | 69/147450 | 0.97 (0.77–1.23) |
Sub-Saharan Africa | 60/152194 | 0.62 (0.48–0.80) | 43/136880 | 0.75 (0.56–1.02) |
South Asia | 139/180867 | 0.78 (0.66–0.92) | 61/139461 | 0.87 (0.68–1.12) |
South-East Asia | 178/284409 | 0.71 (0.61–0.82) | 101/232898 | 0.85 (0.70–1.04) |
Luminal A-like | ||||
Non-immigrants | 11,732/14608517 | 1.00 (ref) | 2418/8335077 | 1.00 (ref) |
High-income | 366/477618 | 1.08 (0.97–1.20) | 84/305153 | 1.03 (0.83–1.28) |
Eastern Europe | 222/593550 | 0.86 (0.76–0.99) | 99/486627 | 0.95 (0.77–1.16) |
Middle East | 81/176786 | 1.06 (0.85–1.32) | 41/147450 | 1.18 (0.86–1.60) |
Sub-Saharan Africa | 21/152194 | 0.43 (0.28–0.66) | 12/136880 | 0.44 (0.25–0.78) |
South Asia | 63/180867 | 0.67 (0.52–0.86) | 25/139461 | 0.73 (0.49–1.08) |
South-East Asia | 83/284409 | 0.63 (0.51–0.79) | 46/232898 | 0.79 (0.59–1.06) |
Luminal B-like/HER2- | ||||
Non-immigrants | 2767/14608517 | 1.00 (ref) | 377/8335077 | 1.00 (ref) |
High-income | 102/477618 | 1.29 (1.06–1.57) | 11/305153 | 0.85 (0.46–1.54) |
Eastern Europe | 55/593550 | 1.02 (0.78–1.33) | 21/486627 | 1.20 (0.77–1.87) |
Middle East | 15/176786 | 0.97 (0.58–1.61) | 8/147450 | 1.41 (0.70–2.83) |
Sub-Saharan Africa | 9/152194 | 0.93 (0.48–1.80) | 6/136880 | 1.30 (0.58–2.92) |
South Asia | 10/180867 | 0.49 (0.27–0.92) | 2/139461 | 0.36 (0.09–1.43) |
South-East Asia | 26/284409 | 0.97 (0.66–1.44) | 9/232898 | 0.95 (0.49–1.84) |
Luminal B-like/HER2+ | ||||
Non-immigrants | 2030/14608517 | 1.00 (ref) | 653/8335077 | 1.00 (ref) |
High-income | 58/477618 | 0.96 (0.74–1.25) | 17/305153 | 0.75 (0.46-.21) |
Eastern Europe | 46/593550 | 0.84 (0.63–1.13) | 30/486627 | 0.97 (0.67–1.40) |
Middle East | 12/176786 | 0.72 (0.41–1.28) | 4/147450 | 0.40 (0.15–1.06) |
Sub-Saharan Africa | 10/152194 | 0.85 (0.46–1.59) | 8/136880 | 0.97 (0.48–1.94) |
South Asia | 20/180867 | 1.05 (0.68–1.63) | 17/139461 | 1.72 (1.06–2.78) |
South-East Asia | 29/284409 | 1.03 (0.71–1.49) | 23/232898 | 1.37 (0.90–2.08) |
HER2+ | ||||
Non-immigrants | 984/14608517 | 1.00 (ref) | 274/8335077 | 1.00 (ref) |
High-income | 27/477618 | 0.93 (0.63–1.36) | 6/305153 | 0.62 (0.28–1.40) |
Eastern Europe | 13/593550 | 0.51 (0.30–0.89) | 6/486627 | 0.45 (0.20–1.01) |
Middle East | 6/176786 | 0.79 (0.35–1.76) | 4/147450 | 0.93 (0.35–2.49) |
Sub-Saharan Africa | 4/152194 | 0.75 (0.28–2.01) | 4/136880 | 1.11 (0.41–2.99) |
South Asia | 18/180867 | 2.02 (1.26–3.23) | 9/139461 | 2.13 (1.09–4.13) |
South-East Asia | 16/284409 | 1.22 (0.75–2.01) | 9/232898 | 1.24 (0.64–2.42) |
TNBC | ||||
Non-immigrants | 1886/14608517 | 1.00 (ref) | 582/8335077 | 1.00 (ref) |
High-income | 59/477618 | 1.03 (0.79–1.34) | 23/305153 | 1.10 (0.73–1.67) |
Eastern Europe | 47/593550 | 0.93 (0.69–1.24) | 27/486627 | 0.92 (0.62–1.35) |
Middle East | 14/176786 | 0.92 (0.54–1.56) | 7/147450 | 0.74 (0.35–1.56) |
Sub-Saharan Africa | 9/152194 | 0.82 (0.43–1.58) | 8/136880 | 1.00 (0.50–2.01) |
South Asia | 21/180867 | 1.19 (0.78–1.84) | 8/139461 | 0.87 (0.43–1.79) |
South-East Asia | 14/284409 | 0.54 (0.32–0.91) | 8/232898 | 0.50 (0.25–1.01) |
Unknown | ||||
Non-immigrants | 2469/14608517 | 1.00 (ref) | 509/8335077 | 1.00 (ref) |
High-income | 69/476027 | 0.97 (0.76–1.23) | 15/305153 | 0.86 (0.51–1.43) |
Eastern Europe | 38/593550 | 0.68 (0.50–0.94) | 13/486627 | 0.55 (0.32–0.96) |
Middle East | 9/176786 | 0.55 (0.28–1.06) | 5/147450 | 0.65 (0.27–1.58) |
Sub-Saharan Africa | 8/152194 | 0.75 (0.37–1.49) | 6/136880 | 0.97 (0.43–2.18) |
South Asia | 8/180867 | 0.40 (0.20–0.79) | 1/139461 | 0.13 (0.02–0.94) |
South-East Asia | 12/284409 | 0.43 (0.24–0.75) | 7/232898 | 0.55 (0.26–1.15) |
Age-adjusted incidence rate ratios by grade
Age 20–75 | Age 20–49 | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Grade I | Grade II | Grade III | Grade I | Grade II | Grade III | |||||||
Cases | IRR (CI) | Cases | IRR (CI) | Cases | IRR (CI) | Cases | IRR (CI) | Cases | IRR (CI) | Cases | IRR (CI) | |
All subtypes | ||||||||||||
Non-immigrants | 4496 | 1.00 (ref) | 9793 | 1.00 (ref) | 5743 | 1.00 (ref) | 605 | 1.00 (ref) | 1981 | 1.00 (ref) | 1776 | 1.00 (ref) |
High-income | 126 | 0.99 (0.83–1.18) | 313 | 1.10 (0.99–1.24) | 177 | 1.04 (0.90–1.21) | 20 | 0.99 (0.63–1.55) | 61 | 0.89 (0.69–1.16) | 63 | 1.01 (0.79–1.30) |
Eastern Europe | 61 | 0.70 (0.54–0.90) | 189 | 0.89 (0.77–1.02) | 133 | 0.87 (0.74–1.04) | 16 | 0.63 (0.38–1.04) | 84 | 0.96 (0.77–1.20) | 79 | 0.92 (0.74–1.16) |
Middle East | 21 | 0.83 (0.54–1.28) | 54 | 0.85 (0.65–1.12) | 50 | 1.09 (0.82–1.44) | 8 | 0.94 (0.47–1.89) | 29 | 1.00 (0.70–1.45) | 27 | 0.97 (0.67–1.42) |
Sub-Saharan Africa | 2 | 0.13 (0.03–0.53) | 19 | 0.47 (0.30–0.73) | 32 | 0.98 (0.69–1.39) | 1 | 0.15 (0.02–1.10) | 12 | 0.53 (0.30–0.93) | 27 | 1.17 (0.80–1.72) |
South Asia | 8 | 0.24 (0.12–0.48) | 56 | 0.72 (0.55–0.93) | 61 | 1.15 (0.89–1.48) | 1 | 0.12 (0.02–0.85) | 21 | 0.74 (0.48–1.13) | 30 | 1.10 (0.77–1.58) |
South-East Asia | 27 | 0.62 (0.42–0.90) | 64 | 0.59 (0.46–0.76) | 74 | 0.94 (0.75–1.19) | 10 | 0.71 (0.38–1.32) | 44 | 0.91 (0.68–1.23) | 41 | 0.88 (0.65–1.20) |
Luminal A-like | ||||||||||||
Non-immigrants | 3311 | 1.00 (ref) | 6154 | 1.00 (ref) | 1645 | 1.00 (ref) | 473 | 1.00 (ref) | 1316 | 1.00 (ref) | 486 | 1.00 (ref) |
High-income | 99 | 1.05 (0.86–1.29) | 196 | 1.10 (0.95–1.27) | 47 | 0.99 (0.74–1.32) | 19 | 1.20 (0.76–1.90) | 42 | 0.95 (0.70–1.29) | 17 | 1.02 (0.63–1.65) |
Eastern Europe | 48 | 0.73 (0.55–0.97) | 124 | 0.92 (0.77–1.10) | 37 | 0.88 (0.64–1.22) | 14 | 0.71 (0.42–1.20) | 54 | 0.96 (0.73–1.26) | 24 | 1.08 (0.71–1.62) |
Middle East | 17 | 0.89 (0.55–1.44) | 41 | 1.01 (0.75–1.38) | 17 | 1.33 (0.82–2.14) | 6 | 0.90 (0.40–2.02) | 22 | 1.17 (0.77–1.78) | 11 | 1.50 (0.82–2.72) |
Sub-Saharan Africa | 2 | 0.17 (0.04–0.69) | 7 | 0.27 (0.13–0.57) | 10 | 1.13 (0.60–2.10) | 1 | 0.20 (0.03–1.41) | 3 | 0.21 (0.07–0.64) | 8 | 1.35 (0.67–2.71) |
South Asia | 8 | 0.32 (0.16–0.65) | 38 | 0.76 (0.56–1.05) | 15 | 1.01 (0.61–1.68) | 1 | 0.15 (0.02–1.08) | 13 | 0.70 (0.40–1.21) | 9 | 1.25 (0.65–2.41) |
South-East Asia | 21 | 0.64 (0.42–0.98) | 45 | 0.65 (0.49–0.87) | 15 | 0.69 (0.41–1.15) | 7 | 0.63 (0.30–1.34) | 30 | 0.96 (0.67–1.38) | 9 | 0.74 (0.38–1.43) |
Age-adjusted incidence rate ratios by ER status
Age 20–75 | Age 20–49 | |||||||
---|---|---|---|---|---|---|---|---|
ER- | ER + | ER- | ER + | |||||
Cases | IRR (CI) | Cases | IRR (CI) | Cases | IRR (CI) | Cases | IRR (CI) | |
Non-immigrants | 3282 | 1.00 (ref) | 17,844 | 1.00 (ref) | 959 | 1.00 (ref) | 3645 | 1.00 (ref) |
High-income | 94 | 0.95 (0.78–1.17) | 561 | 1.09 (1.00–1.18) | 29 | 0.85 (0.59–1.23) | 120 | 0.97 (0.81–1.16) |
Eastern Europe | 66 | 0.76 (0.60–0.98) | 336 | 0.86 (0.77–0.95) | 35 | 0.73 (0.52–1.03) | 155 | 0.96 (0.82–1.12) |
Middle East | 23 | 0.89 (0.59–1.34) | 110 | 0.95 (0.78–1.14) | 13 | 0.85 (0.49–1.47) | 55 | 1.03 (0.79–1.34) |
Sub-Saharan Africa | 13 | 0.71 (0.41–1.22) | 43 | 0.57 (0.42–0.77) | 12 | 0.93 (0.53–1.65) | 28 | 0.66 (0.46–0.96) |
South Asia | 41 | 1.36 (1.00–1.85) | 96 | 0.67 (0.55–0.82) | 16 | 1.06 (0.65–1.75) | 45 | 0.85 (0.64–1.14) |
South-East Asia | 31 | 0.70 (0.49–1.00) | 142 | 0.71 (0.60–0.84) | 18 | 0.70 (0.44–1.11) | 79 | 0.89 (0.71–1.11) |