Background
Methods
Study area and population
Water, soil and crop analysis
Blood analysis
Retrospective ecological mortality studies
Statistical analysis
Ethical approval
Results
Environmental pollution
High-Exposure Area | Low-Exposure Area | GS a
| |||
---|---|---|---|---|---|
Shangba | Xiaozhen | Dongfang | Six villages | ||
N (excluding water source) | 1 | 1 | 1 | 6 | |
pH | |||||
Water source | 3.35 (Wastewater) b
| 7.10 (Huangzhuping) 7.12 (Guizhu) c
| 6.0-9.0 | ||
Irrigation water | 4.92 | 7.75 | 7.76 | 7.02 - 7.35 | 5.50-8.50 |
Well water | 4.77 | 7.06 | 6.88 | 7.04 - 7.56 | 6.5-8.5 |
Cadmium | |||||
Water source (mg/L,×10-3) | 7.09 (Wastewater) b
| 0.09 (Huangzhuping) 0.10 (Guizhu) c
| 5 | ||
Irrigation water (mg/L,×10-3) | 8.31 | 4.25 | 0.66 | <0.001 | 5 |
Well water (mg/L, ×10-3) | 8.88 | 0.13 | 0.07 | <0.001 | 5 |
Soil (mg/kg) | 0.528 | 0.422 | 0.043 | 0.032 - 0.18 | 0.30 |
Rice (mg/kg) | 0.47 | 0.36 | 0.02 | 0.006 - 0.075 | 0.20 |
Avena nula (mg/kg) | 0.13 | 0.06 | 0.01 | 0.004 - 0.060 | 0.20 |
Lead | |||||
Water source (mg/L) | 0.043 (Waste water) b
| 0.01 (Huangzhuping) 0.01 (Guizhu) c
| 0.010 | ||
Irrigation water (mg/L) | 0.045 | 0.035 | 0.013 | <0.01 | 0.200 |
Well water (mg/L) | 0.012 | 0.017 | 0.016 | <0.01 - 0.02 | 0.01 |
Soil (mg/kg) | 600 | 770 | 68 | 7.13 - 19.93 | 300 |
Rice (mg/kg) | 830 | 520 | 280 | <0.05 | 300 |
Avena nula (mg/kg) | 820 | 1690 | 1050 | 0.030 - 0.145 | 300 |
Copper | |||||
Water source (mg/L) | 0.196 (Wastewater) b
| 0.01 (Huangzhuping) 0.01 (Guizhu) c
| 1.000 | ||
Irrigation water (mg/L) | 0.631 | 0.020 | 0.020 | <0.01 | 0.500 |
Well water (mg/L) | 1.570 | 0.020 | 0.045 | <0.01 | 1.00 |
Soil (mg/kg) | 1261 | 147 | 20 | 2.85 - 8.19 | 100 |
Rice (mg/kg) | 5.38 | 3.08 | 2.03 | 0.43 - 0.69 | 10 |
Avena nula (mg/kg) | 1.31 | 0.82 | 0.42 | 0.23 - 1.09 | - d
|
Zinc | |||||
Water source (mg/L) | 13.700 (Wastewater) b
| 0.01 (Huangzhuping) 0.01 (Guizhu) c
| 1.000 | ||
Irrigation water (mg/L) | 25.200 | 0.048 | 0.005 | <0.01 - 0.84 | 2.00 |
Well water (mg/L) | 4.89 | 0.024 | 0.011 | <0.01 - 0.49 | 1.00 |
Soil (mg/kg) | 680 | 227 | 68 | 2.85 - 8.19 | 250 |
Rice (mg/kg) | 29.40 | 20.70 | 13.80 | 7.50 - 10.90 | 50 |
Avena nula (mg/kg) | 20.80 | 5.12 | 3.73 | 2.89 - 7.94 | - d
|
Social-demographic characteristics and heavy metal levels in blood
Geometric mean (SD) | |||||
---|---|---|---|---|---|
Characteristics | n | Cadmium, ug/L | Lead, μg/dL | Copper, mg/L | Zinc, mg/L |
The high-exposure area (H) (I-III) | 563 | 24.10 (3.52) a
| 38.91 (0.39) a
| 0.82 (1.49) | 8.38 (1.96) a
|
Shangba (I) | 198 | 34.80 (2.96) | 67.36 (0.24) | 0.84 (1.42) | 11.23 (1.75) |
Xiaozhen(II) | 177 | 10.33 (4.16) | 10.35 (0.40) | 0.73 (1.26) | 5.52 (1.45) |
Dongfang (III) | 188 | 21.37 (3.11) | 62.55 (0.28) | 0.86 (1.71) | 8.94 (2.09) |
The low-exposure area (L) (IV-IX) | 589 | 1.87 (2.48) a
| 4.46 (0.18) a
| 0.81 (1.24) | 7.96 (1.32) a
|
Zhongxin (IV) | 172 | 1.69 (2.34) | 5.81 (0.17) | 0.86 (1.27) | 8.47 (1.34) |
Shaping (V) | 72 | 2.06 (2.57) | 4.70 (0.18) | 0.81 (1.16) | 7.80 (1.30) |
Shuikou (VI) | 72 | 1.90 (2.51) | 3.79 (0.15) | 0.85 (1.29) | 8.34 (1.19) |
Fengshan (VII) | 104 | 1.23 (2.45) | 4.34 (0.18) | 0.79 (1.14) | 8.17 (1.24) |
Mashan (VIII) | 86 | 2.15 (2.12) | 2.97 (0.19) | 0.72 (1.19) | 7.51 (1.27) |
Madun (IX) | 83 | 3.03 (2.40) | 4.47 (0.15) | 0.76 (1.25) | 7.01 (1.45) |
Age, yrs | |||||
18-39 | |||||
H | 106 | 24.47 (3.15) | 39.98 (0.42) | 0.78 (1.34) | 8.10 (1.95) |
L | 73 | 1.64 (2.37) | 4.37 (0.17) | 0.83 (1.38) | 7.93 (1.27) |
40-59 | |||||
H | 328 | 25.44 (3.50) | 36.96 (0.40) | 0.82 (1.57) | 8.16 (1.93) |
L | 373 | 1.83 (2.47) | 4.41 (0.18) | 0.81 (1.21) | 7.98 (1.33) |
60-74 | |||||
H | 99 | 23.09 (3.93) | 44.08 (0.40) | 0.85 (1.36) | 9.80 (2.13) |
L | 97 | 2.12 (2.66) | 4.55 (0.17) | 0.79 (1.22) | 7.99 (1.33) |
≥75 | |||||
H | 30 | 27.03 (3.96) | 41.12 (0.24) | 0.81 (1.50) | 7.56 (1.64) |
L | 46 | 2.11 (2.24) | 4.73 (0.20) | 0.82 (1.25) | 7.79 (1.29) |
Smoking | |||||
Never | |||||
H | 436 | 24.40 (3.58) | 37.72 (0.40) | 0.80 (1.40) | 8.15 (1.92) |
L | 392 | 1.43 (2.11) | 4.15 (0.18) | 0.82 (1.22) | 7.89 (1.28) |
Former | |||||
H | 29 | 28.46 (2.31) | 45.92 (0.29) | 0.87(1.36) | 10.19 (1.97) |
L | 43 | 1.76 (2.52) | 4.50 (0.19) | 0.86 (1.32) | 7.22 (1.58) |
Current | |||||
H | 98 | 26.27 (3.63) | 42.56 (0.40) | 0.85 (1.88) | 9.00 (2.11) |
L | 154 | 3.79 (2.46) | 5.31 (0.17) | 0.77 (1.24) | 8.34 (1.33) |
Alcohol | |||||
Never | |||||
H | 364 | 23.55 (3.57) | 39.71 (0.39) | 0.82 (1.52) | 8.27 (1.99) |
L | 332 | 1.77 (2.37) | 4.24 (0.18) | 0.82 (1.24) | 7.95 (1.29) |
Former | |||||
H | 44 | 31.05 (2.90) | 45.44 (0.28) | 0.84 (1.33) | 8.36(1.70) |
L | 46 | 1.91 (2.55) | 4.24 (0.15) | 0.86 (1.32) | 7.16 (1.56) |
Current | |||||
H | 155 | 26.70 (3.58) | 35.50 (0.43) | 0.81 (1.47) | 8.67 (1.97) |
L | 211 | 2.03 (2.63) | 4.86 (0.17) | 0.78 (1.20) | 8.15 (1.30) |
Cancer mortality and rate ratio
Population | All cancers | Esophagus cancer | Stomach cancer | Lung cancer | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
(Years) | Statistic | Both | Men | Women | Both | Men | Women | Both | Men | Women | Both | Men | Women |
The HEA | Ea
| 194 | 125 | 68 | 30 | 17 | 13 | 60 | 34 | 26 | 36 | 24 | 12 |
(2000-2007) | Rateb
| 265.1 | 332.5 | 191.1 | 41.0 | 45.2 | 36.5 | 82.0 | 90.4 | 73.1 | 49.2 | 63.9 | 33.7 |
Comparison: | Ea
| 138 | 99 | 39 | 22 | 14 | 8 | 19 | 17 | 2 | 27 | 22 | 5 |
The LEA (2000-2007) | Rateb
| 5 114.1 | 156.3 | 67.7 | 18.2 | 22.1 | 13.9 | 15.7 | 26.9 | 3.5 | 22.3 | 34.7 | 8.7 |
Rate ratioc
| 2.32 | 2.13 | 2.83 | 2.25 | 2.05 | 2.63 | 5.28 | 3.37 | 21.06 | 2.20 | 1.84 | 3.89 | |
95% CId
| 1.87-2.89 | 1.63-2.77 | 1.91-4.19 | 1.30-3.91 | 1.01-4.15 | 1.09-6.35 | 3.12-8.74 | 1.88-6.03 | 5.00-88.71 | 1.34-3.63 | 1.03-3.28 | 1.37-11.03 | |
Pd
| <0.001 | <0.001 | <0.001 | 0.003 | 0.043 | 0.025 | <0.001 | <0.001 | <0.001 | 0.001 | 0.036 | 0.006 | |
Comparison: Wengyuan County (2004-2005) | Rate†
| 138.3 | 183.5 | 98.0 | 17.0 | 16.1 | 17.6 | 37.0 | 48.6 | 26.4 | 22.2 | 38.0 | 10.3 |
Rate ratioc
| 1.92 | 1.81 | 1.95 | 2.41 | 2.81 | 2.08 | 2.22 | 1.86 | 2.77 | 2.22 | 1.68 | 3.27 | |
95% CIe
| 1.66-2.20 | 1.51-2.14 | 1.53-2.46 | 1.66-3.40 | 1.69-4.41 | 1.16-3.46 | 1.71-2.83 | 1.31-2.57 | 1.85-4.00 | 1.58-3.04 | 1.10-2.46 | 1.77-5.56 | |
Pe
| <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | 0.017 | <0.001 | 0.001 | <0.001 | <0.001 | 0.018 | 0.001 | |
Comparison: the RAGDP (2004-2005) | Rate†
| 131.8 | 167.3 | 90.3 | 11.8 | 16.7 | 7.1 | 15.0 | 20.4 | 9.9 | 26.6 | 39.8 | 14.6 |
Rate ratioc
| 2.01 | 1.99 | 2.12 | 3.48 | 2.71 | 5.14 | 5.46 | 4.43 | 7.73 | 1.85 | 1.61 | 2.31 | |
95% CIe
| 1.74-2.30 | 1.65-2.35 | 1.66-2.67 | 2.39-4.90 | 1.63-4.25 | 2.86-8.57 | 4.21-6.99 | 3.12-6.12 | 4.91-10.64 | 1.32-2.53 | 1.05-2.35 | 1.25-3.92 | |
Pe
| <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | 0.001 | 0.030 | 0.010 |
Population | Liver cancer | Leukocythemia | Non-Hodgin disease | Other cancersf
| |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
(Years) | Statistic | Both | Men | Women | Both | Men | Women | Both | Men | Women | Both | Men | Women |
The HEA | Ea
| 38 | 27 | 11 | 8 | 7 | 1 | 4 | 3 | 1 | 21 | 14 | 7 |
(2000-2007) | Rateb
| 51.9 | 71.8 | 30.9 | 10.9 | 18.6 | 2.8 | 5.5 | 8.0 | 2.8 | 28.7 | 37.2 | 19.7 |
Comparison: | Ea
| 39 | 28 | 11 | 7 | 4 | 4 | 0 | 0 | 0 | 23 | 13 | 10 |
The LEA | Rateb
| 32.2 | 44.3 | 19.1 | 5.8 | 6.3 | 6.9 | 0 | 0 | 0 | 19.0 | 20.5 | 17.4 |
(2000-2007) | Rate ratioc
| 1.61 | 1.62 | 1.62 | 1.89 | 2.95 | 0.41 | - | - | - | 1.51 | 1.81 | 1.13 |
95% CId
| 1.03-2.52 | 0.96-2.75 | 0.70-3.74 | 0.69-5.21 | 0.86-10.1 | 0.05-3.62 | - | - | - | 0.84-2.73 | 0.85-3.86 | 0.43-2.98 | |
Pd
| 0.035 | 0.070 | 0.254 | 0.211 | 0.070 | 0.403 | - | - | - | 0.170 | 0.117 | 0.799 | |
Comparison: Wengyuan County (2004-2005) | Rate†
| 42.3 | 64.0 | 21.5 | 4.5 | 5.2 | 3.8 | 1.2 | 1.3 | 1.1 | 16.1 | 10.3 | 17.3 |
Rate ratioc
| 1.23 | 1.12 | 1.44 | 2.43 | 3.58 | 0.74 | 4.58 | 6.15 | 2.55 | 1.78 | 3.61 | 1.14 | |
95% CIe
| 0.88-1.67 | 0.75-1.61 | 0.76-2.50 | 1.13-4.62 | 1.57-7.10 | 0.04-3.65 | 1.44-11.0 | 1.56-16.7 | 0.13-12.64 | 1.11-2.63 | 1.99-5.73 | 0.51-2.31 | |
Pe
| 0.209 | 0.526 | 0.239 | 0.026 | 0.005 | 0.868 | 0.002 | 0.015 | 0.382 | 0.018 | <0.001 | 0.650 | |
Comparison: the RAGDP (2004-2005) | Rate†
| 39.8 | 63.1 | 16.7 | 4.0 | 4.2 | 3.8 | 1.8 | 2.3 | 1.3 | 32.8 | 20.8 | 36.9 |
Rate ratioc
| 1.30 | 1.14 | 1.85 | 2.73 | 4.41 | 0.74 | 3.06 | 3.48 | 2.15 | 0.88 | 1.79 | 0.53 | |
95% CIe
| 0.94-1.77 | 0.77-1.63 | 0.97-3.22 | 1.27-5.18 | 1.94-8.76 | 0.04-3.65 | 0.95-7.20 | 0.89-9.49 | 0.11-10.72 | 0.56-1.31 | 1.00-2.87 | 0.24-1.07 | |
Pe
| 0.110 | 0.483 | 0.059 | 0.014 | 0.001 | 0.868 | 0.059 | 0.068 | 0.447 | 0.557 | 0.051 | 0.080 |
Relationships between heavy metal exposure and the risk of cancer mortality
Both sexesa
| ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
All cancer | Esophageal cancer | Stomach cancer | Lung cancer | |||||||
Bb
| P | Bb
| P | Bb
| P | Bb
| P | |||
Cd | 0.301 | 0.002c
| 0.082 | 0.770 | 0.584 | 0.012c
| 0.279 | 0.062 | ||
Pb | 0.260 | 0.039c
| -0.045 | 0.881 | 0.559 | 0.046c
| 0.263 | 0.117 | ||
Zn | -0.119 | 0.900 | 0.134 | 0.944 | 0.102 | 0.963 | 0.107 | 0.929 | ||
Both sexes
d
| ||||||||||
All cancers
|
Stomach cancer
| |||||||||
B
c
|
P
|
Tolerance
e
|
VIF
f
|
RRC
j
|
B
c
|
P
|
Tolerance
e
|
VIF
f
|
RRC
h
| |
Cd | 0.483 | 0.018c
| 0.172 | 5.826 | 0.376616 | 0.723 | 0.156 | 0.168 | 5.964 | 0.303854 |
Pb | -0.216 | 0.228 | 0.172 | 5.826 | 0.188513 | -0.168 | 0.739 | 0.168 | 5.964 | 0.440660 |
Discussion
Womena
| Mena
| |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
All cancer | Esophageal cancer | Stomach cancer | Lung cancer | All cancers | Esophageal cancer | Stomach cancer | Lung cancer | |||||||||
Bb
| P | Bb
| P | Bb
| P | Bb
| P | Bb
| P | Bb
| P | Bb
| P | Bb
| P | |
Cd | 0.365 | 0.001c
| 0.204 | 0.286 | 0.549 | 0.037c
| 0.324 | 0.067 | 0.276 | 0.062 | 0.472 | 0.071 | 0.558 | 0.070 | 0.163 | 0.493 |
Pb | 0.374 | 0.026c
| 0.175 | 0.476 | 0.684 | 0.020c
| 0.275 | 0.272 | 0.221 | 0.101 | 0.411 | 0.624 | 0.424 | 0.151 | 0.194 | 0.350 |
Zn | -0.034 | 0.977 | 1.361 | 0.323 | 0.943 | 0.691 | 0.444 | 0.759 | -0.366 | 0.718 | 0.235 | 0.893 | -0.280 | 0.898 | -0.312 | 0.831 |
Women
d
| ||||||||||||||||
All cancers
|
Stomach cancer
| |||||||||||||||
B
c
|
P
|
Tolerance
e
|
VIF
f
|
RRC
j
|
B
c
|
P
|
Tolerance
e
|
VIF
f
|
RRC
h
| |||||||
Cd | 0.491 | 0.024c
| 0.197 | 5.073 | 0.469722 | 0.221 | 0.491 | 0.245 | 4.075 | 0.454158 | ||||||
Pb | -0.175 | 0.424 | 0.197 | 5.073 | 0.205384 | 0.453 | 0.291 | 0.245 | 4.075 | 0.342160 |