Figures
- FIGURE 1
Cases included in analysis of molecular clusters of tuberculosis in London (2010–2014).
- FIGURE 2
Median interval between successive tuberculosis cases in molecular clusters in London (2010–2014), by cluster size.
- FIGURE 3
Forest plot of adjusted odds ratios (with 95% confidence intervals) from multivariable multinomial logistic regression analysis (table 4), by number of cases in molecular cluster: a) n=2, b) n=3–20 and c) n>20 cases.
- FIGURE 4
a–h) Locations of significant spatial clusters of cases within eight molecular clusters of tuberculosis (TB) in London (2010–2014), overlaid on smoothed incidence maps. Ovals represent areas of significant spatial clustering (p<0.05) with more than 10 cases of the given molecular cluster compared with the general distribution of TB cases. The proportions of cases in molecular clusters compared with all other TB cases are represented through kernel density estimation (bandwidth 5 km).
Tables
- TABLE 1
Distribution of tuberculosis cases and molecular clusters in London (2010–2014), by cluster size
Cases in cluster Cases Clusters 1 (not clustered) 3329 (44.6) 2 1044 (14.0) 522 (52.4) 3–20 2290 (30.7) 454 (45.6) >20 795 (10.7) 20 (2.0) Total 7458 (100) 996 (100) Data are presented as n (%).
- TABLE 2
Baseline characteristics of tuberculosis cases in molecular clusters of different sizes in London (2010–2014)
All cases Not clustered Cases in cluster n 2 3–20 >20 Sex Female 2911 1320 (45.3) 430 (14.8) 874 (30.0) 287 (9.9) Male 4546 2008 (44.2) 614 (13.5) 1416 (31.1) 508 (11.2) Age group years 0–14 158 43 (27.2) 24 (15.2) 60 (38.0) 31 (19.6) 15–44 5284 2346 (44.4) 731 (13.8) 1628 (30.8) 579 (11.0) 45–64 1369 585 (42.7) 207 (15.1) 433 (31.6) 144 (10.5) ≥65 647 355 (54.9) 82 (12.7) 169 (26.1) 41 (6.3) Ethnic group White 829 308 (37.2) 119 (14.4) 277 (33.4) 125 (15.1) Black-Caribbean 258 49 (19.0) 38 (14.7) 113 (43.8) 58 (22.5) Black-African 1722 609 (35.4) 242 (14.1) 614 (35.7) 257 (14.9) Black-Other 97 28 (28.9) 15 (15.5) 37 (38.1) 17 (17.5) Indian 2185 1126 (51.5) 303 (13.9) 615 (28.1) 141 (6.5) Pakistani 673 313 (46.5) 96 (14.3) 181 (26.9) 83 (12.3) Bangladeshi 365 246 (67.4) 38 (10.4) 69 (18.9) 12 (3.3) Chinese 86 49 (57.0) 11 (12.8) 21 (24.4) 5 (5.8) Mixed/other 1177 561 (47.7) 176 (15.0) 347 (29.5) 93 (7.9) Place of birth Non-UK 6223 2990 (48.0) 876 (14.1) 1801 (28.9) 556 (8.9) UK 1150 301 (26.2) 156 (13.6) 463 (40.3) 230 (20.0) Time since entry to UK years 0–1 1095 540 (49.3) 159 (14.5) 298 (27.2) 98 (9.0) 2–4 1391 740 (53.2) 202 (14.5) 347 (24.9) 102 (7.3) 5–9 1156 538 (46.5) 162 (14.0) 339 (29.3) 117 (10.1) ≥10 1803 785 (43.5) 261 (14.5) 583 (32.3) 174 (9.7) Occupation Other 2465 1146 (46.5) 342 (13.9) 759 (30.8) 218 (8.8) None 2615 1129 (43.2) 367 (14.0) 788 (30.1) 331 (12.7) Education 1074 452 (42.1) 148 (13.8) 342 (31.8) 132 (12.3) Healthcare 275 137 (49.8) 44 (16.0) 81 (29.5) 13 (4.7) Pulmonary disease No 3006 1553 (51.7) 389 (12.9) 815 (27.1) 249 (8.3) Yes 4452 1776 (39.9) 655 (14.7) 1475 (33.1) 546 (12.3) Sputum smear Negative 2371 1066 (45.0) 338 (14.3) 734 (31.0) 233 (9.8) Positive 2062 745 (36.1) 314 (15.2) 718 (34.8) 285 (13.8) Previous diagnosis No 6821 3088 (45.3) 941 (13.8) 2078 (30.5) 714 (10.5) Yes 354 124 (35.0) 57 (16.1) 125 (35.3) 48 (13.6) Previous treatment No 13 6 (46.2) 1 (7.7) 6 (46.2) Yes 261 82 (31.4) 41 (15.7) 98 (37.5) 40 (15.3) Drug resistance# No 6738 3033 (45.0) 921 (13.7) 2114 (31.4) 670 (9.9) Yes 667 276 (41.4) 111 (16.6) 161 (24.1) 119 (17.8) Inpatient No 4649 2100 (45.2) 636 (13.7) 1441 (31.0) 472 (10.2) Yes 2731 1190 (43.6) 397 (14.5) 831 (30.4) 313 (11.5) Homeless No 6917 3116 (45.0) 969 (14.0) 2135 (30.9) 697 (10.1) Yes 294 96 (32.7) 44 (15.0) 85 (28.9) 69 (23.5) Drug use No 6822 3110 (45.6) 967 (14.2) 2079 (30.5) 666 (9.8) Yes 307 75 (24.4) 30 (9.8) 111 (36.2) 91 (29.6) Alcohol use No 6460 2911 (45.1) 908 (14.1) 1979 (30.6) 662 (10.2) Yes 328 106 (32.3) 42 (12.8) 124 (37.8) 56 (17.1) Prison No 6938 3140 (45.3) 984 (14.2) 2129 (30.7) 685 (9.9) Yes 225 53 (23.6) 22 (9.8) 78 (34.7) 72 (32.0) Risk factor count¶ 0 6688 3081 (46.1) 950 (14.2) 2020 (30.2) 637 (9.5) 1 508 187 (36.8) 64 (12.6) 180 (35.4) 77 (15.2) 2 159 41 (25.8) 19 (12.0) 58 (36.5) 41 (25.8) 3 84 19 (22.6) 8 (9.5) 26 (31.0) 31 (36.9) 4 19 1 (5.3) 3 (15.8) 6 (31.6) 9 (47.4) Mean IMD quintile+ 2.45 2.40 2.41 2.15 Data are presented as n or n (% row). IMD: index of multiple deprivation. #: resistance to any first-line antibiotic; ¶: cumulative number of social risk factors (history of homelessness, illicit drug use, alcohol misuse, imprisonment) reported by each case; +: IMD quintile of Lower Layer Super Output Area within London (lowest is most deprived).
- TABLE 3
Single-variable multinomial logistic regression analysis for risk factors associated with tuberculosis cases in molecular clusters of different sizes in London (2010–2014)
Cases in cluster n 2 3–20 >20 Sex Female 1 1 1 Male 0.94 (0.81–1.08) 1.07 (0.95–1.19) 1.16 (0.99–1.37)# Age group years 0–14 1.79 (1.08–2.97)# 2.01 (1.35–2.99)# 2.92 (1.82–4.68)# 15–44 1 1 1 45–64 1.14 (0.95–1.36)# 1.07 (0.93–1.23) 1.00 (0.81–1.22)# ≥65 0.74 (0.57–0.96)# 0.69 (0.57–0.83)# 0.47 (0.33–0.65)# Ethnic group White 1 1 1 Black-Caribbean 2.01 (1.25–3.22)# 2.56 (1.77–3.72)# 2.92 (1.89–4.50)# Black-African 1.03 (0.79–1.33) 1.12 (0.92–1.37) 1.04 (0.81–1.34)# Black-Other 1.39 (0.72–2.69) 1.47 (0.88–2.46)# 1.50 (0.79–2.83)# Indian 0.70 (0.54–0.89)# 0.61 (0.50–0.73)# 0.31 (0.24–0.40)# Pakistani 0.79 (0.58–1.08)# 0.64 (0.50–0.82)# 0.65 (0.47–0.90)# Bangladeshi 0.40 (0.27–0.60)# 0.31 (0.23–0.43)# 0.12 (0.06–0.22)# Chinese 0.58 (0.29–1.16)# 0.48 (0.28–0.81)# 0.25 (0.10–0.65)# Mixed/other 0.81 (0.62–1.06)# 0.69 (0.56–0.85)# 0.41 (0.30–0.55)# Place of birth Non-UK 1 1 1 UK 1.77 (1.44–2.18)# 2.55 (2.18–2.99)# 4.11 (3.38–4.99)# Time since entry to UK years 0–1 1 1 1 2–4 0.93 (0.73–1.17) 0.85 (0.70–1.03)# 0.76 (0.56–1.02)# 5–9 1.02 (0.80–1.31) 1.14 (0.94–1.39)# 1.20 (0.89–1.61) ≥10 1.13 (0.90–1.41) 1.35 (1.13–1.61)# 1.22 (0.93–1.60)# Occupation Other 1 1 1 None 1.09 (0.92–1.29) 1.05 (0.93–1.20) 1.54 (1.27–1.86)# Education 1.10 (0.88–1.37) 1.14 (0.97–1.35)# 1.54 (1.21–1.96)# Healthcare 1.08 (0.75–1.54) 0.89 (0.67–1.19) 0.50 (0.28–0.90)# Pulmonary disease No 1 1 1 Yes 1.47 (1.28–1.70)# 1.58 (1.42–1.77)# 1.92 (1.63–2.26)# Sputum smear Negative 1 1 1 Positive 1.33 (1.11–1.59)# 1.40 (1.22–1.61)# 1.75 (1.44–2.13)# Previous diagnosis No 1 1 1 Yes 1.51 (1.09–2.08)# 1.50 (1.16–1.93)# 1.67 (1.19–2.35)# Previous treatment No 1 1 1 Yes 3.03 (0.35–26.12) 1.20 (0.37–3.86) Drug resistance¶ No 1 1 1 Yes 1.32 (1.05–1.67)# 0.84 (0.68–1.02)# 1.95 (1.55–2.46)# Inpatient No 1 1 1 Yes 1.10 (0.95–1.27)# 1.02 (0.91–1.14) 1.17 (1.00–1.37)# Homeless No 1 1 1 Yes 1.47 (1.02–2.12)# 1.29 (0.96–1.74)# 3.21 (2.33–4.43)# Drug use No 1 1 1 Yes 1.29 (0.84–1.98) 2.21 (1.64–2.98)# 5.67 (4.13–7.78)# Alcohol use No 1 1 1 Yes 1.27 (0.88–1.83)# 1.72 (1.32–2.24)# 2.32 (1.66–3.25)# Prison No 1 1 1 Yes 1.32 (0.80–2.19) 2.17 (1.52–3.09)# 6.22 (4.32–8.95)# Risk factor count+ 0 1 1 1 1 1.11 (0.83–1.49) 1.47 (1.19–1.82)# 1.99 (1.51–2.63)# 2 1.50 (0.87–2.60)# 2.16 (1.44–3.23)# 4.84 (3.11–7.52)# 3 1.37 (0.60–3.13) 2.09 (1.15–3.78)# 7.89 (4.43–14.06)# 4 9.73 (1.01–93.64)# 9.15 (1.10–76.07)# 43.53 (5.51–344.20)# IMD quintile§ 0.59 (0.54–0.63)# 0.86 (0.81–0.91)# 0.62 (0.57–0.68)# Data are presented as adjusted odds ratio (95% CI). IMD: index of multiple deprivation. #: p<0.2, included in initial multivariable model. ¶: resistance to any first-line antibiotic; +: cumulative number of social risk factors (history of homelessness, illicit drug use, alcohol misuse, imprisonment) reported by each case; §: IMD quintile of Lower Layer Super Output Area (LSOA) within London (lowest is most deprived), included as a continuous variable in multilevel model accounting for random effects of LSOA.
- TABLE 4
Multivariable multinomial logistic regression analysis for risk factors associated with tuberculosis cases in molecular clusters of different sizes in London (2010–2014), adjusted for random effects of Lower Layer Super Output Area (LSOA)
Cases in cluster n 2 3–20 >20 Sex Female 1 1 1 Male 0.98 (0.83–1.16) 1.08 (0.95–1.23) 1.14 (0.94–1.38) Age group years 0–14 1.15 (0.65–2.02) 1.18 (0.76–1.83) 1.29 (0.75–2.22) 15–44 1 1 1 45–64 1.13 (0.92–1.39) 0.97 (0.82–1.15) 0.82 (0.64–1.04) ≥65 0.68 (0.50–0.93) 0.71 (0.56–0.90) 0.52 (0.35–0.78) Ethnic group White 1 1 1 Black-Caribbean 2.1 (1.25–3.55) 3.13 (2.08–4.71) 3.64 (2.23–5.94) Black-African 1.35 (0.99–1.86) 1.86 (1.46–2.38) 2.09 (1.49–2.91) Black-Other 1.88 (0.92–3.84) 1.92 (1.07–3.45) 2.29 (1.13–4.66) Indian 0.95 (0.70–1.30) 1.02 (0.80–1.30) 0.78 (0.55–1.11) Pakistani 1.08 (0.75–1.55) 1.02 (0.76–1.36) 1.51 (1.02–2.24) Bangladeshi 0.60 (0.38–0.94) 0.53 (0.37–0.76) 0.26 (0.13–0.50) Chinese 0.78 (0.37–1.64) 0.78 (0.44–1.40) 0.63 (0.24–1.68) Mixed/other 1.12 (0.81–1.54) 1.11 (0.86–1.43) 0.89 (0.61–1.29) Place of birth Non-UK 1 1 1 UK 1.45 (1.12–1.87) 2.13 (1.75–2.58) 2.93 (2.28–3.77) Occupation Other 1 1 1 None 1.04 (0.85–1.27) 0.96 (0.82–1.12) 1.18 (0.94–1.49) Education 1.04 (0.82–1.31) 1.04 (0.87–1.24) 1.31 (1.01–1.70) Healthcare 1.00 (0.69–1.45) 0.82 (0.60–1.11) 0.47 (0.25–0.87) Pulmonary disease No 1 1 1 Yes 1.46 (1.24–1.72) 1.48 (1.30–1.68) 1.47 (1.21–1.79) Drug resistance# No 1 1 1 Yes 1.25 (0.96–1.61) 0.82 (0.65–1.03) 1.75 (1.34–2.28) Risk factor count¶ 0 1 1 1 1 0.83 (0.59–1.15) 1.12 (0.88–1.42) 1.36 (0.99–1.87) 2 1.00 (0.53–1.89) 1.59 (1.00–2.52) 2.46 (1.45–4.18) 3 0.86 (0.35–2.12) 1.28 (0.67–2.45) 3.75 (1.96–7.16) 4 4.35 (0.39–48.50) 4.13 (0.45–37.58) 16.64 (1.98–139.88) IMD quintile+ 0.98 (0.91–1.04) 1.00 (0.95–1.06) 0.90 (0.83–0.97) Data are presented as adjusted odds ratio (95% CI). IMD: index of multiple deprivation. #: resistance to any first-line antibiotic; ¶: cumulative number of social risk factors (history of homelessness, illicit drug use, alcohol misuse, imprisonment) reported by each case; +: IMD quintile of LSOA within London (lowest is most deprived), included as a continuous variable in multilevel model accounting for random effects of LSOA.
