Figure 1Process used for literature search.
Figure 2(A) Odds ratios (ORs) for DDT exposure and breast cancer. (B) Funnel plot of all included studies.
Figure 3(A) Odds ratios for DDT exposure and breast cancer in population-based case–control studies. (B) Funnel plot of population-based case–control studies.
Table 1Summary of papers included in the meta-analysis for DDT exposure and breast cancer risk
Author (year) |
Study years |
Country |
Design |
n (cases/controls) |
Biological specimen |
OR (95% CI) |
Aronson (2000) [26]
|
1995–1997 |
Canada |
Hospital CC |
217/213 |
Adipose tissue |
1.10 (0.78–1.55) |
Charlier (2004) [14]
|
2001–2002 |
Belgium |
Population CC |
231/290 |
Serum |
2.21 (1.41–3.48) |
Cohn (2007) [27]
|
1959–1967 |
USA |
Hospital CC |
129/129 |
Serum |
1.29 (0.85–1.96) |
Dello Lacovo (1999) [28]
|
1997–1998 |
Italy |
Population CC |
170/195 |
Serum |
1.02 (0.68–1.54) |
Demers (2000) [29]
|
1994–1997 |
Canada |
Population CC |
315/307 |
Plasma |
0.91 (0.70–1.17) |
Demers (2000) [29]
|
1994–1997 |
Canada |
Hospital CC |
315/219 |
Plasma |
1.01 (0.74–1.39) |
Dorgan (1999) [30]
|
1977–1987 |
USA |
Nested CC |
105/207 |
Serum |
0.70 (0.47–0.99) |
Gammon (2002) [15]
|
1996–1997 |
USA |
Population CC |
643/427 |
Serum |
1.20 (0.76–1.90) |
Gatto (2007) [31]
|
1995–1998 |
USA |
Population CC |
355/327 |
Serum |
1.05 (0.82–1.35) |
Helzlsouer (1999) [32]
|
1974 |
USA |
Nested CC |
235/235 |
Serum |
0.94 (0.71–1.25) |
Helzlsouer (1999) [32]
|
1989 |
USA |
Nested CC |
105/105 |
Serum |
0.88 (0.56–1.38) |
Hoyer (1998) [33]
|
1976 |
Denmark |
Nested CC |
237/469 |
Serum |
0.88 (0.56–1.37) |
Hoyer (2000) [34]
|
1976–1978/1981–1983 |
Denmark |
Nested CC |
240/477 |
Serum |
1.04 (0.70–1.55) |
Ibarluzea (2004) [16]
|
1996–1998 |
Spain |
Hospital CC |
198/260 |
Adipose tissue |
1.16 (0.83–1.62) |
Itoh (2009) [35]
|
2001–2005 |
Japan |
Population CC |
349/349 |
Serum |
0.74 (0.48–1.13) |
Iwasaki (2008) [17]
|
1990–1995 |
Japan |
Nested CC |
139/278 |
Plasma |
1.23 (0.80–1.90) |
Krieger (1994) [36]
|
1964–1969 |
USA |
Nested CC |
150/150 |
Serum |
1.31 (0.82–2.09) |
Laden (2001) [37]
|
1989–1990 |
USA |
Nested CC |
372/372 |
Plasma |
0.79 (0.61–1.01) |
Liljegren (1998) [38]
|
1993–1995 |
Sweden |
Hospital CC |
43/35 |
Adipose tissue |
0.40 (0.10–1.20) |
Lopez-Carrillo (1997) [39]
|
1994–1996 |
Mexico |
Hospital CC |
141/141 |
Serum |
0.68 (0.43–1.07) |
McCready (2004) [18]
|
1995–1997 |
Canada |
Hospital CC |
68/52 |
Adipose tissue |
2.48 (1.08–5.71) |
Mendonca (1999) [40]
|
1995–1996 |
Brazil |
Hospital CC |
162/331 |
Serum |
1.05 (0.75–1.46) |
Millikan (2000) [41]
|
1993–1996 |
USA |
Population CC |
748/659 |
Plasma |
1.07 (0.86–1.32) |
Moysich (1998) [42]
|
1986–1991 |
USA |
Population CC |
154/192 |
Serum |
1.15 (0.74–1.79) |
Olaya-Contreras (1998) [21]
|
1995–1996 |
Colombia |
Hospital CC |
153/153 |
Serum |
1.56 (1.02–2.39) |
Pavuk (2003) [43]
|
1997–1999 |
USA |
Hospital CC |
24/85 |
Serum |
1.49 (0.45–4.87) |
Raaschou-Nielsen (2005) [44]
|
1993–1997 |
Denmark |
Nested CC |
363/363 |
Adipose tissue |
0.87 (0.69–1.10) |
Romieu (2000) [22]
|
1990–1995 |
Mexico |
Population CC |
120/126 |
Serum |
2.02 (1.14–3.57) |
Rubin (2005) [45]
|
1981–1987 |
USA |
Population CC |
63/63 |
Serum |
0.97 (0.41–2.32) |
Schecter (1997) [46]
|
1994 |
Vietnam |
Hospital CC |
21/21 |
Serum |
0.69 (0.23–2.07) |
Stellman (2000) [47]
|
1994–1996 |
USA |
Hospital CC |
232/323 |
Adipose tissue |
0.94 (0.66–1.33) |
van't Veer (1997) [48]
|
1991–1992 |
Five European countries |
Hospital CC |
265/341 |
Adipose tissue |
0.75 (0.52–1.08) |
Wolff (1993) [11]
|
1985–1991 |
USA |
Population CC |
58/171 |
Serum |
2.30 (1.31–4.04) |
Wolff (2000) [49]
|
1994–1996 |
USA |
Hospital CC |
151/317 |
Serum |
0.86 (0.61–1.22) |
Wolff (2000) [50]
|
1987–1992 |
USA |
Nested CC |
110/213 |
Serum |
0.83 (0.50–1.37) |
Zheng (1999) [51]
|
1994–1997 |
USA |
Hospital CC |
304/304 |
Adipose tissue |
1.02 (0.73–1.41) |
Zheng (2000) [52]
|
1995–1997 |
USA |
Hospital CC |
475/502 |
Serum |
1.01 (0.79–1.28) |
Table 2Meta-analysis of the effect of the exposure to DDT on the risk of breast cancer according to subgroup
Studies included |
No. of Studies |
OR |
95% CI |
Heterogeneity
|
Egger’s test (p for bias) |
p-value |
I2 (%) |
Type of study design |
Hospital CC |
16 |
1.02 |
0.91 to 1.15 |
0.183 |
24.0 |
0.780 |
Population CC |
11 |
1.19 |
0.99 to 1.44 |
0.004 |
61.3 |
0.212 |
Nested CC |
10 |
0.90 |
0.81 to 1.01 |
0.554 |
0.0 |
0.274 |
Study years |
2000s |
2 |
1.28 |
0.44 to 3.71 |
0.001 |
91.5 |
– |
1990s |
27 |
1.03 |
0.94 to 1.24 |
0.034 |
35.9 |
0.169 |
1980s |
4 |
0.87 |
0.69 to 1.09 |
0.575 |
0.0 |
0.908 |
1970s |
2 |
0.92 |
0.73 to 1.17 |
0.808 |
0.0 |
– |
1960s |
2 |
1.30 |
0.95 to 1.77 |
0.962 |
0.0 |
– |
Type of biologic specimen |
Serum |
24 |
1.07 |
0.93 to 1.11 |
0.006 |
47.0 |
0.365 |
Plasma |
5 |
0.97 |
0.85 to 1.11 |
0.325 |
14.1 |
0.910 |
Adipose tissue |
8 |
0.98 |
0.83 to 1.16 |
0.141 |
36.0 |
0.228 |
Country |
North America |
22 |
1.01 |
0.92 to 1.10 |
0.185 |
21.0 |
0.524 |
Europe |
8 |
1.02 |
0.81 to 1.29 |
0.010 |
62.0 |
0.246 |
Asia |
3 |
0.92 |
0.63 to 1.36 |
0.226 |
32.8 |
0.900 |
South America |
4 |
1.20 |
0.78 to 1.83 |
0.012 |
72.8 |
0.707 |