IARC MONOGRAPHS ON THE EVALUATION OF CARCINOGENIC ...

Table 10 (contd)
Reference Area Units of
observation/
number of units
Srivatanakul
et al. (1991a)
Hatch et al.
(1993)
Omer et al.
(1998)
Thailand Selected areas of
Thailand; 5
Exposure measure(s) Outcome measure(s) Covariate Results Comments
Surveys of local residents,
aflatoxin measured in
urine and in serum,
50–100 subjects per area
Taiwan Townships; 8 Mean urine levels of
various aflatoxins.
Measured on a total of
250 randomly selected
subjects in 8 townships
Sudan Two areas, one
high- risk, one
low-risk
Peanut butter samples
collected in markets and
analysed for AFB1. Type
of storage assessed
Incidence rates of HCC
and cholangiocarcinoma
1980–82.
Standardized proportionate
incidence ratio
(PIR)
HCC mortality rate in
the area of the
township
Fragmentary data
indicate that risk of
liver cancer is higher in
one area than the other.
Same 100–200
individuals per
area as for
aflatoxin,
HBsAg, anti-
HBs, anti-HBc
and liver fluke
(OV)
HBsAg;
smoking status,
alcohol
consumption
HCC Cholangiocarcinoma
Serum aflatoxin –0.75 (p = 0.14) –0.03 (p = 0.96)
Urinary aflatoxin –0.64 (p = 0.25) 0.17 (p = 0.78)
Anti-OV titre –0.37 (p = 0.54) 0.98 (p = 0.004)
HBsAg –0.45 (p = 0.44) 0.27 (p = 0.66)
Univariate correlation
between mean urinary
aflatoxin and area HCC
rates:
men, 0.83 (p = 0.012)
women, 0.49 (p = 0.22)
– Aflatoxin consumption
levels were higher in the
presumed high-risk area
than in the presumed lowrisk
area.
Univariate correlations
between area HCC rates and
mean HBsAg were around
0.50. When individuals were
used as units of observation,
with the area mortality rate
attributed to the individual,
the correlations between
urinary aflatoxins and HCC
were considerably attenuated.
Only two areas compared.
Unreliable measures of liver
cancer incidence
AFB1, aflatoxin B1; anti-HBc, antibody to hepatitis B core antigen; HBsAg, hepatitis B surface antigen; HBV, hepatitis B virus; HCC, hepatocellular carcinoma; OV, Opisthorchis viverrini; PHC,
primary hepatocellular carcinoma; PLC, primary liver cancer
AFLATOXINS 197