Golestan cohort study of oesophageal cancer: feasibility and first results.

Abstract

To investigate the incidence of oesophageal cancer (EC) in the Golestan province of North-East Iran, we invited 1349 rural and urban inhabitants of Golestan province aged 35-80 to undergo extensive lifestyle interviews and to provide biological samples. The interview was repeated on a subset of 130 participants to assess reliability of questionnaire and medical information. Temperature at which tea was consumed was measured on two occasions by 110 subjects. Samples of rice, wheat and sorghum were tested for fumonisin contamination. An active follow-up was carried out after 6 and 12 months. A total of 1057 subjects (610 women and 447 men) participated in this feasibility study (78.4% participation rate). Cigarette smoking, opium and alcohol use were reported by 163 (13.8%), 93 (8.8%) and 39 (3.7%) subjects, respectively. Tobacco smoking was correlated with urinary cotinine (kappa = 0.74). Most questionnaire data had kappa > 0.7 in repeat measurements; tea temperature measurement was reliable (kappa = 0.71). No fumonisins were detected in the samples analysed. During the follow-up six subjects were lost (0.6%), two subjects developed EC (one dead, one alive); in all, 13 subjects died (with cause of death known for 11, 84.6%). Conducting a cohort study in Golestan is feasible with reliable information obtained for suspected risk factors; participants can be followed up for EC incidence and mortality.

Full text

Page 1

Golestan cohort study of oesophageal cancer: feasibility and first
results
A Pourshams1, M Saadatian-Elahi2, M Nouraie1, AF Malekshah1, N Rakhshani1, R Salahi3, A Yoonessi1,
S Semnani3, F Islami1, M Sotoudeh1, S Fahimi1,2, AR Sadjadi1, D Nasrollahzadeh1, K Aghcheli1, F Kamangar4,
CC Abnet4, F Saidi1, V Sewram5, PT Strickland6, SM Dawsey4, P Brennan2, P Boffetta2and R Malekzadeh*,1
1Digestive Disease Research Center, Shariati Hospital, Tehran University of Medical Sciences, North Kargar Avenue, 14114 Tehran, Iran;2International
Agency for Research on Cancer, Lyon, France;3Golestan University of Medical Sciences, Gorgan, Iran;4Cancer Prevention Studies Branch, Center for
Cancer Research, National Cancer Institute, Bethesda, MD, USA;5PROMEC Unit, Medical Research Council, Tygerberg, South Africa;6Johns Hopkins
Bloomberg School of Public Health, Baltimore, MD, USA
To investigate the incidence of oesophageal cancer (EC) in the Golestan province of North-East Iran, we invited 1349 rural and urban
inhabitants of Golestan province aged 35–80 to undergo extensive lifestyle interviews and to provide biological samples. The
interview was repeated on a subset of 130 participants to assess reliability of questionnaire and medical information. Temperature at
which tea was consumed was measured on two occasions by 110 subjects. Samples of rice, wheat and sorghum were tested for
fumonisin contamination. An active follow-up was carried out after 6 and 12 months. A total of 1057 subjects (610 women and 447
men) participated in this feasibility study (78.4% participation rate). Cigarette smoking, opium and alcohol use were reported by 163
(13.8%), 93 (8.8%) and 39 (3.7%) subjects, respectively. Tobacco smoking was correlated with urinary cotinine (k¼0.74). Most
questionnaire data had k 40.7 in repeat measurements; tea temperature measurement was reliable (k¼0.71). No fumonisins were
detected in the samples analysed. During the follow-up six subjects were lost (0.6%), two subjects developed EC (one dead, one
alive); in all, 13 subjects died (with cause of death known for 11, 84.6%). Conducting a cohort study in Golestan is feasible with
reliable information obtained for suspected risk factors; participants can be followed up for EC incidence and mortality.
British Journal of Cancer (2005) 92, 176–181. doi:10.1038/sj.bjc.6602249
Published online 14 December 2004
& 2005 Cancer Research UK
www.bjcancer.com
Keywords: oesophageal cancer; cohort; Golestan; turkmen; Iran
? ?????????????????????????????????????????????????????
The earliest reports of high incidence of oesophageal cancer (EC)
in the Northern parts of Iran date from the early 1970s (Kmet and
Mahboubi, 1972). A population-based cancer registry was estab-
lished in 1969, as a joint effort between Tehran University and the
International Agency for Research on Cancer (IARC), in the city of
Babol in Mazandaran province, on the Eastern side of the Caspian
Littoral, and subsequently extended to the Western province of
Gilan. This registry emphasised the high incidence of EC in the
eastern portion close to Turkmenistan (Gonbad and Gorgan
districts, now Golestan province), particularly in the semidesert
plain settled mainly by people of Turkmen ethnicity, with
incidence rates of 109 out of 100000 among men and 174 out of
100000 among women (Kmet and Mahboubi, 1972; Mahboubi et al,
1973). Sharp changes in the incidence of EC were evident in
adjacent regions, being 15 among men and 5.5 out of 100000
among women in Gilan, 300km to the West. A series of studies in
the 1970s were prematurely stopped in 1978, and though not
conclusive in explaining the increased risk, pointed to several
factors including: (i) a diet deficient in fruits and vegetables
(Cook-Mozaffari et al, 1979); (ii) a thermal injury from consump-
tion of very hot beverages (Cook-Mozaffari et al, 1979; Ghadirian,
1987); and (iii) carcinogen exposure from lifestyle factors
including opium consumption (Joint Iran-IARC Study Group,
1977; Dowlatshahi and Miller, 1985; Ghadirian et al, 1985).
Aetiological hypotheses related to diet, including temperature of
beverages (Munoz and Day, 1996), exposure to mycotoxins such as
fumonisins (Wang et al, 2000; Abnet et al, 2001a; Shephard et al,
2002), and use of illicit products can be best addressed in
prospective studies, in which measurement error is reduced and
recall bias is absent (White et al, 1998). To reopen the
investigation, an initiative involving the Digestive Diseases
Research Centre (DDRC) of Tehran University of Medical Sciences,
the IARC, and the US National Cancer Institute (NCI) has
therefore been established, aiming to conduct a cohort study in
this region. Such a prospective cohort study will include at least
50000 individuals, and requires a carefully planned feasibility
phase. Here we present the details of the feasibility study and
initial results on lifestyle factors, including tea temperature.
METHODS
A protocol for the pilot study was developed jointly by research
teams from the DDRC, IARC and NCI with the aim (i) to evaluate
the logistical aspects of the project, including the response rate of
Received 2 August 2004; revised 20 September 2004; accepted 15
October 2004; published online 14 December 2004
*Correspondence: Dr R Malekzadeh; E-mail: malek@ams.ac.ir
British Journal of Cancer (2005) 92, 176–181
& 2005 Cancer Research UKAll rights reserved 0007– 0920/05$30.00
www.bjcancer.com
Epidemiology

Page 2

the study population, the acceptability of the questionnaires, and
the procedures for collecting and storing biological samples; (ii) to
assess the reliability of interviews by conducting repeated inter-
views on a sample of subjects; (iii) to validate questionnaire-based
opium consumption data with biological markers of opium
consumption measured in urine and hair samples. The protocol
concentrated on identifying a methodology for recruiting subjects,
developing a lifestyle questionnaires and a nutritional component,
collecting information on anthropometric measures, assessing the
maximum temperature at which an individual could comfortably
drink tea, and collecting biological samples. The main question-
naire was developed in order to obtain information on demo-
graphic and socioeconomic details as well as past and present
medical history, types of fuel used for heating and cooking, history
of cancer in the relatives, gastrointestinal symptoms, and body
shape at age 15, age 30 and present age. Information on recent and
past consumption of alcohol, cigarettes, nass (a smokeless tobacco
product containing also ash, lime and oil) and opium was
collected. In a subset of 130 subjects, a detailed semiquantitative
food-frequency questionnaire (FFQ) was administered four times
and 12 24-h dietary recalls for two consecutive days administered
monthly during 1 year. The urinary excretion of nitrogen was
estimated from four 24-h urine collection of 118 subjects for
determination of protein intake by Isakson formula, and plasma
levels of b-carotene, retinol, vitamin C and vitamin E from two
nonfasting blood collections in 125 subjects.
Subjects for the pilot study were selected during the summer of
2002 from Gonbad, the second biggest city of the province, and
three rural villages in the surrounding region in Golestan province
(Incheborun, Hali-Akhond and Aq-Abad). Recruitment took place
at the Golestan Cohort Study Centre (GCSC) in Gonbad, a research
centre specifically established for this project, and in the health
house of each village. Health houses are present in each village and
staffed by two auxiliary health personnel (Behvarz), who are in
charge of vaccination programs, family planning, report of death
and major communicable diseases and initial primary care
treatment. In the villages, trained Behvarz selected households
by systematic clustering according to household number, con-
tacted all household members aged between 35 and 80 (N¼704)
and thoroughly explained them the purpose and procedure of the
study. Residents in Gonbad (N¼645) were selected by household
sampling and contacted at their home by expert local health
professionals, who thoroughly explained them the purpose and
procedure of the study. Individuals were invited to participate by
attending the health house or the GCSC at a specific time for
interview. Interviewers were local physicians and, in the case of
dietary interviews, nutritionists who were trained for this purpose.
Exclusion criteria used in this study were: (i) unwillingness to
participate at any stage of the study for any reason; (ii) being a
temporary resident; and (iii) having had a diagnosis of upper
gastrointestinal cancer. Before interview, a written informed
consent was obtained. Support from local leaders was also obtained.
The interview was conducted by a trained general physician
either in the local language (Turkmen) or in Persian, depending on
the subject’s preference. After the interview, a limited physical
examination was performed including the measurement of height,
weight, number of lost teeth and blood pressure. A repeated
interview was performed on 130 subjects – 50 urban and 80 rural –
2 months after the first interview.
In order to measure temperature of tea drinking, subjects were
offered during the interview a fresh cup or glass of tea. A second
cup was kept by the interviewer, who measured the temperature
with an alcohol thermometer at the moment in which the subject
drank his/her tea. Since the analysis of repeated measurements
showed poor reliability of this method (k 0.09, based on 130
repeats), an alternative approach was tested on 110 randomly
selected participants, who were re-contacted. In this case, two
measurements were made at the home of the subjects one day
apart. The health worker prepared a fresh cup of tea and measured
the temperature using a digital thermometer. When the tea was at
751C, subjects were asked if they could drink the tea. If this was not
possible, the tea was let to cool to 701C, and subjects were asked
again if they could drink the tea. This procedure was repeated, at
51C intervals, until it was possible for the subjects to drink the tea.
Blood samples (10ml) were collected in the health houses, kept
in a freezer box and transported to the GCSC every evening, where
they were separated into buffy coat, plasma and red blood cells and
stored in colour-coded 1.8-ml tubes at ?801C. Subjects were also
asked to provide a hair sample, taken from the nape of the neck, as
well as a nail sample and a urine sample.
Hair and nail samples were stored at room temperature and
urine samples at ?201C. In order to assess the validity of self-
reported tobacco smoking, urine samples from 96 participants
were selected randomly and sent to the Johns Hopkins University,
Baltimore, MD, USA, where they were measured for cotinine using
NicoMetersstrips.
Samples (100g) of raw rice, sorghum and wheat used for bread
production were collected from selected households included in
the feasibility study. They were kept at ?101C until they were sent
to the Medical Research Council, Tygerberg, South Africa, for
fumonisin analysis. The dry grain samples were ground to a meal
and analysed for the presence of fumonisins B1, B2and B3using
the method of Sydenham et al (1996). In brief, ground samples
(20g) were homogenised in 70% aqueous methanol (100ml) for
3min. Aliquots of the filtered extracts (10ml) were cleaned up on
strong anion exchange (SAX) solid phase extraction (SPE)
cartridges (Bond Elut LRCs) that were conditioned with methanol
(5ml) and 70% aqueous methanol (5ml). The extract was eluted
with 1% acetic acid in methanol and evaporated to dryness at 601C
under a continuous flow of nitrogen. Residues were redissolved in
methanol, and an aliquot was derivatised with o-phthaldialdehyde
prior to separation on a reversed phase HPLC system using
fluorescence detection.
Study participants were contacted 6 and 12 months after
recruitment in rural areas by the Behvarz and in urban areas by
health professionals. Information on date and cause of death was
collected for those who died, as was information of incidence of
EC. In addition, local hospitals, including in particular the Atrak
Clinic, a hospital based Clinic specialised in gastrointestinal
diseases and established in Gonbad by DDRC, were contacted to
identify further cases of EC. Subjects included in the study were
advised to refer to the Atrak Clinic for symptoms possibly
associated with digestive diseases.
The study protocol and the informed consent used for this
investigation were approved by the ethical review committees of
DDRC and the IARC. The analysis of data and samples was
approved by ethical review committee of the NCI.
RESULTS
In Gonbad, 438 subjects of the 645 who we invited visited the
GCSC for interview and provided biological samples (participation
rate 67.9%); in the three rural villages, 619 individuals participated
successfully (participation rate 87.9%). The higher response rate
among the rural inhabitants is explained by their employment
close to home in agricultural occupations, and their flexible
working hours and proximity of their homes with work place and
health houses. In total, 1057 subjects were enrolled into the
feasibility study, including 447 men and 610 women (overall
participation rate, 78.4%). Selected demographic characteristics of
the study population are reported in Table 1. Results of the
analysis for use of alcohol, tobacco and opium are shown in
Table 2. Alcohol drinking was restricted to men and was rarely
reported in the rural areas. Tobacco smoking was mainly reported
by men. Consumption of nass and opium was particularly
Feasibility of EC Cohort Study in Golestan Iran
A Pourshams et al
177
British Journal of Cancer (2005) 92(1), 176–181
& 2005 Cancer Research UK
Epidemiology

Page 3

common among rural men, although some rural women admitted
opium consumption. Urinary cotinine was positive in 46% of the
study subjects; there was a good agreement between urinary
cotinine positivity and self-reported current tobacco smoking or
nass use (Pearson correlation coefficient¼0.73, Po0.0001).
Symptoms related to gastro-oesophageal reflux disease were
commonly reported among both rural and urban participants
(Table 3). Recent regurgitation was reported by 49.8% of rural and
48.6% of urban participants. The prevalence of self-reported heart
diseases and diabetes was significantly higher among urban
subjects, and that of chronic connective tissue and joint diseases
was higher among rural subjects. The prevalence of other chronic
diseases was comparable in the two groups. The prevalence of
overweight and obesity was high, in particular among urban
participants. The average total number of teeth was 15 (s.d.710)
among rural and 16 (s.d.711) among urban participants.
The analysis of reliability of questionnaire information, based
on repeated interview on 130 subjects, showed that k values were
above 0.7 for most variables, including tobacco, nass, opium and
alcohol consumption, as well as for most self-reported symptoms
and for anthropometric measures (Table 4). Measurement of
HBsAg, blood group and Rh group was performed on repeated
blood samples, with 100% agreement.
The detailed results of the repeated measurements of tea
temperature are shown in Table 5. The level of agreement between
the two separate measurements of tea temperature was good
(weighted k¼0.71) with most disagreements occurring in adjacent
categories. Among the six individuals who reported being able to
drink tea in the highest temperature category (4701C), five of
them gave the same response at the second measurement, whereas
the sixth reported drinking tea in the 66–701C range.
The analysis of 10 grain samples revealed no fumonisin
contamination and following these preliminary results, no further
analyses were performed.
Table 1Selected characteristics of study population, by residence
Rural (N¼619)Urban (N¼438)
N%N%
Age group (year)
o40
40–49
50–59
60–69
X70
99
216
159
80
65
15.9
34.9
25.8
12.9
10.5
75
154
98
68
43
17.1
35.2
22.4
15.5
9.8
Sex
Male
Female
270
349
43.6
56.4
177
261
40.4
59.6
Ethnicity
Turkmen
Persian
Turk
Other
59996.8
0.5
—
2.7
65
285
68
20
14.8
65.1
15.5
4.6
3
0
17
Education level
Illiterate
Primary school
Guidance
High school
College
464
126
74.9
20.4
1.1
1.3
1
115
144
32
80
58
26.3
32.9
7.3
18.3
13.2
7
8
6
Table 2 Use of alcohol, tobacco and opium, by sex and residence
ExposureRural men, N (%)Urban men, N (%)P-valuea
Rural women, N (%) Urban women, N (%)P-valuea
Alcohol drinking
Ever
Frequencyb
o50gday?1
50–150gday?1
4150gday?1
8 (3.0)31 (17.3)
o0.00010 (0.0) 0 (0.0)—
1 (12.5)
3 (37.5)
4 (50.0)
20 (66.7)
4 (13.3)
6 (20.0)
0.02—
—
—
—
—
—
—
Tobacco smoking
Ever
Recent
Frequency (cpd)b
o2
2–3
4–6
81 (30.0)
53 (19.6)
69 (38.5)
42 (23.5)
0.06
0.3
4 (1.1)
1 (0.3)
9 (3.4)
5 (1.9)
0.04
0.009
3 (3.9)
54 (71.1)
19 (25.0)
3 (4.6)
50 (76.9)
12 (18.5)
0.62 (50.0)
2 (50.0)
0 (0.0)
2 (28.6)
4 (57.1)
1 (14.3)
0.6
Nass use
Ever
Recent
Frequencyb
o1day?1
1–5day?1
6–20day?1
420day?1
50 (18.5)
47 (17.4)
3 (1.7)
1 (0.6)
o0.0001
o0.0001
2 (0.6)
2 (0.6)
0 (0.0)
—
0.22
—
2 (4.1)
17 (34.7)
20 (40.8)
10 (20.4)
0 (0.0)
1 (33.3)
2 (66.7)
0 (0.0)
0.80 (0.0)
2 (100.0)
0 (0.0)
—
—
—
—
—
Opium use
Ever
Recent
Frequencyb
o1day?1
1day?1
2–5day?1
6+ per day
58 (21.5)
53 (19.6)
14 (7.9)
9 (4.5)
o0.0001
o0.0001
19 (5.1)
15 (4.3)
2 (0.8)
1 (0.4)
0.03
0.04
12 (23.1)
14 (26.9)
22 (42.3)
4 (7.7)
4 (28.6)
7 (50.0)
3 (21.4)
0 (0.0)
0.23 (18.7)
6 (37.5)
7 (43.7)
0 (0.0)
0 (0.0)
1 (50.0)
1 (50.0)
0 (0.0)
0.8
aP-value of difference between rural and urban populations (w2test, two-sided).bPercentages refer to ever users cpd, cigarettes per day. Numbers might not add up because of
missing values.
Feasibility of EC Cohort Study in Golestan Iran
A Pourshams et al
178
British Journal of Cancer (2005) 92(1), 176–181
& 2005 Cancer Research UK
Epidemiology

Page 4

There was good correlation based on food groups and nutrients
comparing 12 recalls to four FFQ questionnaires. There was
acceptable correlation between questionnaire data and biomarker
measurement except for vitamin E.
The detailed data on dietary and nutritional variables is in the
process of a separate publication, but overall there were significant
difference in consumption of some food group and nutrients
between Persians and Turkmen. Persians consume significantly
more legumes, fruits, vegetables while Turkmen consume more
nonalcoholic beverage (tea). Protein intake in Persian woman was
more than Turkmen woman.
Results on opium exposure have been reported previously
(Abnet et al, 2004); results on dietary factors, including nutrient
level, will be the subject of a separate report.
The results of the follow-up are summarised in Table 6. One
study participant was lost to follow-up (0.1%) and five subjects
emigrated from the province (0.5%). Information on cause of
death was available from 11 out of 13 subjects who died during the
first year of follow-up (84.6%). Six of these 11 deaths were due to
cardiovascular diseases, two to car accident, one subject died from
breast cancer and another one from pneumonia. Two cases of EC
were identified, one of whom died from the disease.
DISCUSSION
The pilot study has demonstrated the feasibility of recruiting fairly
large numbers of adult subjects from urban and rural areas of the
Golestan province with a high response rate, and of obtaining both
interview information and biological samples. The high participa-
tion rate and the successful follow-up in rural areas were due to the
excellent health infrastructure with 95% coverage in the study area,
the close relationship between Behvarz and inhabitants of the area
and the support obtained from local leaders.
Repeat interviews on a subsample confirmed the reliability of
most questionnaire data. The proposed method for obtaining
information on tea temperature was also reliable. The pilot study
Table 3
diseases and body mass index, by residence
Prevalence of gastroesophageal reflux disease (GERD), chronic
Rural, N¼619
N (%)
Urban, N¼438
N (%) P-valuea
Any GERD symptomb
Never
1–6 times per week
Daily
316 (51.0)
110 (17.7)
82 (13.2)
219 (50.0)
74 (16.9)
66 (15.1)
0.7
Heartburn
Never
1–6 times per week
Daily
349 (56.3)
88 (14.2)
51 (8.2)
287 (65.5)
49 (11.2)
45 (10.3)
0.2
Regurgitation
Never
1–6 times per week
Daily
318 (51.4)
101 (16.2)
66 (10.6)
219 (50.0)
66 (15.1)
54 (12.3)
0.6
History of chronic diseases (ever)
Any diseases
Heart diseases
Stroke
Hypertension
Diabetes
Pulmonary diseases
Connective tissue and joint
disease
Renal failure
169 (27.3)
7 (1.1)
7 (1.1)
81 (13.1)
17 (2.7)
16 (2.6)
38 (6.1)
158 (36.1)
30 (6.8)
7 (1.6)
71 (16.2)
35 (8.0)
11 (2.5)
4 (0.9)
0.002
o0.0001
0.5
0.1
0.0001
0.9
o0.0001
1 (0.2)0 (0.0) 0.4
BMI (kgm?2)
o18.5
18.5–24.9
25.0–29.9
30.0+
55 (8.9)
284 (45.7)
177 (28.5)
107 (17.2)
3 (0.7)
109 (24.6)
168 (38.0)
163 (36.7)
o0.0001
aP-value of difference between rural and urban populations (w2test, two-sided).
bHeartburn or regurgitation.
Table 4 Repeatability of selected characteristics
CharacteristicAgreement (%)
j
Gender
Residence place
Age
Ethnicity
Marital status
Education level
Working at present
Working start age
Cancer in relatives
Alcohol drinking status
Cigarette smoking status
Cigarette smoking (amount)
Nass use status
Nass use (amount)
Opium use status
Opium use (amount)
Heartburn (frequency)
Regurgitation (frequency)
Vomiting (frequency)
Teeth count
Ischaemic heart disease
Stroke
Hypertension
Diabetes mellitus
Water supply
Income
House surface (m2)
Height
Weight
Body mass index
97.8
100.0
100.0
99.3
99.3
96.3
91.9
67.1
97.1
99.3
99.3
100.0
99.3
70.0
99.3
81.8
68.9
84.4
85.7
88.3
96.4
100.0
96.4
99.3
100.0
55.6
71.4
85.2
89.3
82.3
0.95
1.00
1.00
0.98
0.96
0.94
0.62
0.53
0.92
0.93
0.97
1.00
0.95
0.58
0.96
0.73
0.60
0.79
0.72
0.86
0.78
1.00
0.83
0.85
1.00
0.39
0.59
0.83
0.86
0.72
Table 5 Repeatability of measurement of tea temperature
Second day
First day
o60606570
470Total 1st
o60
60
65
70
470
Total 2nd
1
3
1
0
0
5
400
1
3
6
1
0
0
0
0
5
5
5
24
13
0
0
41
10
23
13
38
40
21
6
110
0
4613
Table 6Results of the follow-up
Outcome 1–6 months7–12 monthsTotal
Loss-to-follow-up
Emigration
Deaths
Known cause of death
Cases of oesophageal cancer
1
1
7
6
0
0
4
6
5
2a
1
5
13
11
2a
aIncluding one alive case.
Feasibility of EC Cohort Study in Golestan Iran
A Pourshams et al
179
British Journal of Cancer (2005) 92(1), 176–181
& 2005 Cancer Research UK
Epidemiology

Page 5

also demonstrated that there exists significant between-subject
variation for all of the main exposures of interest, and in particular
tea temperature and opium consumption, which will increase our
ability to detect their aetiological role in EC.
Prevalence of adenocarcinoma of the oesophagus in Gonbad is
still low (Islami et al, 2004). However, the high prevalence of
reflux-like symptoms in Gonbad, as compared to Asia (Ho et al,
1998), overweight and obesity suggest that an increasing incidence
of adenocarcinoma of distal oesophagus may be observed in the
future in this population. The low number of teeth suggests that
the subjects have poor oral hygiene and associated oral bacteria
may have a role in the aetiology of EC in this population. Previous
reports have shown that poor oral hygiene is associated with
increased production of carcinogenic nitrosamines (Nair et al,
1992) and tooth loss has been associated with increased risk of
oesophageal squamous cell and gastric cancers in another high-
risk population (Abnet et al, 2001b). The high prevalence of self-
reported ischaemic heart disease, diabetes and hypertension is
consistent with our finding of high mortality from cardiovascular
diseases during the first year of follow-up.
Our pilot study confirms previous findings of a low prevalence of
tobacco smoking, nass use and alcohol drinking in this population,
particularly among women (Joint Iran-IARC Study Group, 1977).
These factors are therefore probably not major aetiological factors
for EC in this area (Islami et al, 2004). Although, mycotoxin
contamination of cereals does not seem to play an important
aetiological role, our analyses were based on a limited number of
samples, and any conclusion on the possible role of fumonisins in
this population is premature. We plan to conduct further analyses
(i) to characterise the contamination of cereals by different fungal
groups and (ii) to measure fumonisins in hair samples of study
subjects. Opium use, on the other hand, remains a fairly common
habit, particularly among rural men of Turkmen ethnicity. Previous
studies from north Iran suggested a role of opium metabolites in
oesophageal carcinogenesis (Hewer et al, 1978; Malaveille et al,
1982; Friesen et al, 1985, 1987; Ribeiro Pinto and Swann, 1997).
In total, 51 of the subjects included in the validation study
(46.4%) drank tea on two occasions at a temperature of 651C or
higher. This strongly suggests that high tea temperature is a factor
in EC in this population. A study from the 1970s showed 62% of
Iranians in the high-risk region, as opposed to 19% in the low-risk
region, used to drink their tea at a temperature above 651C
(Ghadirian, 1987). Furthermore, inhabitants of high-risk areas
consumed 2.5 times more tea than their counterparts in the low-
risk areas. A role of drinking of hot beverages, such as tea and
mate ´, has been reported in studies conducted in different regions,
including United Kingdom (Sharp et al, 2001), South America
(Castellsague et al, 2000; Sewram et al, 2003) and Turkey (Onuk
et al, 2002).
This Pilot study also successfully validated the reliability of our
semiquantitive FFQ for food groups, energy and nutrients
(macronutrients, retinol, vitamins C and E, b-carotene), all
considered to be important in EC aetiology. We would therefore
be able to use this reliable FFQ in measurements of food intake for
all nutrient groups in our main cohort study.
The short-term follow-up required for this pilot study was found
to be straightforward and feasible, using information from a
combination of sources including Behvarz in rural areas, health
professionals in Gonbad, local hospitals, Atrak Clinic, and the
ongoing Golestan cancer registry. We intend to rely on these
sources for long-term follow-up in the actual cohort and will also
add an active follow-up team of three trained interviewers to
contact all urban study subjects once each year.
From the total annual number of cases seen at Atrak Clinic and
the number of the reported cases to the ongoing cancer registry, we
expect that 400 EC cases will be observed in the first 5 years of the
actual cohort study.
In conclusion, a cohort study is feasible in Northern Iran,
allowing relevant suspected aetiological factors to be investigated
both in terms of prevalence of exposure and ability to obtain
reliable and valid measurements. Our experience may be relevant
to other developing countries, in which the health system is based
on local health centres covering the whole population, local
expertise in epidemiological research is available, and the project
has local support.
ACKNOWLEDGEMENTS
This study was supported by funds from DDRC and IARC. We
would like to thank Dr Hajiamin Marjani, Dr Mohamad R
Eshraghian, Dr Soliman Alaghi, Dr Omid Mozaffari, Dr Elham
Jafari, Dr Shahabedin M Amani, Dr Farhad Gharangic, and Ms
Goharshad Goglani for their collaboration and assistance. We also
enjoyed a close collaboration of Golestan health deputy Dr
Mohamad Naemi, Dr Ali Aghapor and Dr Khalil Jalil Pestei chief
of Gonbad health district and Behvarz working in the study areas.
Our appreciation is expressed to all the kind people of Gonbad
who were the subjects of this study for their collaboration.
REFERENCES
Abnet CC, Borkowf CB, Qiao YL, Albert PS, Wang E, Merrill Jr AH, Mark
SD, Dong ZW, Taylor PR, Dawsey SM (2001a) Sphingolipids as
biomarkers of fumonisin exposure and risk of esophageal squamous
cell carcinoma in china. Cancer Causes Control 12: 821–828
Abnet CC, Qiao YL, Mark SD, Dong ZW, Taylor PR, Dawsey SM (2001b)
Prospective study of tooth loss and incident esophageal and gastric
cancers in China. Cancer Causes Control 12: 847–854
Abnet CC, Saadatian-Elahi M, Pourshams A, Boffetta P, Feizzadeh A,
Brennan P, Taylor PR, Kamangar F, Dawsey SM, Malekzadeh R (2004)
Reliability and validity of opiate use self-report in a population at high
risk for esophageal cancer in Golestan, Iran. Cancer Epidemiol
Biomarkers Prev 13: 1068–1070
Castellsague X, Munoz N, De Stefani E, Victora CG, Castelletto R, Rolon PA
(2000) Influence of mate drinking, hot beverages and diet on esophageal
cancer risk in South America. Int J Cancer 88(4): 658–664
Cook-Mozaffari PJ, Azordegan F, Day NE, Ressicaud A, Sabai C, Aramesh B
(1979) Oesophageal cancer studies in the Caspian Littoral of Iran: results
of a case–control study. Br J Cancer 39: 293–309
Dowlatshahi K, Miller RJ (1985) Role of opium in esophageal cancer: a
hypothesis. Cancer Res 45: 1906–1907
Friesen M, O’Neill IK, Malaveille C, Garren L, Hautefeuille A, Bartsch H
(1987) Substituted hydroxyphenanthrenes in opium pyrolysates impli-
cated in oesophageal cancer in Iran: structures and in vitro metabolic
activation of a novel class of mutagens. Carcinogenesis 8: 1423–1432
Friesen M, O’Neill IK, Malaveille C, Garren L, Hautefeuille A, Cabral JR,
Galendo D, Lasne C, Sala M, Chouroulinkov I (1985) Characterization
and identification of 6 mutagens in opium pyrolysates implicated in
oesophageal cancer in Iran. Mutat Res 150: 177–191
Ghadirian P (1987) Thermal irritation and esophageal cancer in northern
Iran. Cancer 60: 1909–1914
Ghadirian P, Stein GF, Gorodetzky C, Roberfroid MB, Mahon GA, Bartsch
H, Day NE (1985) Oesophageal cancer studies in the Caspian littoral of
Iran: some residual results, including opium use as a risk factor. Int J
Cancer 35: 593–597
Hewer T, Rose E, Ghadirian P, Castegnaro M, Malaveille C, Bartsch H, Day
N (1978) Ingested mutagens from opium and tobacco pyrolysis products
and cancer of the oesophagus. Lancet 2: 494–496
Ho KY, Kang JY, Seow A (1998) Prevalence of gastrointestinal symptoms in
a multiracial Asian population, with particular reference to reflux-type
symptoms. Am J Gastroenterol 93(10): 1816–1822
Feasibility of EC Cohort Study in Golestan Iran
A Pourshams et al
180
British Journal of Cancer (2005) 92(1), 176–181
& 2005 Cancer Research UK
Epidemiology

Page 6

Islami F, Kamangar F, Aghcheli K, Fahimi S, Semnani S, Taghavi N, Marjani
HA, Merat S, Nasseri-Moghaddam S, Pourshams A, Nouraie M, Khatibian M,
Abedi B, Brazandeh MH, Ghaziani R, Sotoudeh M, Dawsey SM, Abnet CC,
Taylor PR, Malekzadeh R (2004) Epidemiologic features of upper gastro-
intestinal tract cancers in Northeastern Iran. Br J Cancer 90: 1402–1406
Joint Iran-International Agency for Research on Cancer Study Group
(1977) Esophageal cancer studies in the Caspian littoral of Iran: results of
population studies – a prodrome. J Natl Cancer Inst 59: 1127–1138
Kmet J, Mahboubi E (1972) Esophageal cancer in the Caspian littoral of
Iran: initial studies. Science 175: 846–853
Mahboubi E, Kmet J, Cook PJ, Day NE, Ghadirian P, Salmasizadeh S (1973)
Oesophageal cancer studies in the Caspian littoral of Iran: the Caspian
cancer registry. Br J Cancer 28: 197–214
Malaveille C, Friesen M, Camus AM, Garren L, Hautefeuille A, Bereziat JC,
Ghadirian P, Day NE, Bartsch H (1982) Mutagens produced by the
pyrolysis of opium and its alkaloids as possible risk factors in cancer of
the bladder and oesophagus. Carcinogenesis 3: 577–585
Munoz N, Day NE (1996) Esophageal cancer. In Cancer Epidemiology and
Prevention Schottenfeld D, Fraumeni JF (eds). pp 681–706. New York:
Oxford University Press
Nair J, Havovi S, Chakradeo P, Jakhi SA, Bhide SV (1992) Effect of oral
hygiene on nitrosamine formation in the mouth. In Nitroso Compounds:
Biological Mechanisms, Exposure and Cancer Etiology O’Neill IK, Bartsch
H (eds). Lyon: International Agency for Research on Cancer
Onuk MD, Oztopuz A, Memik F (2002) Risk factors for esophageal cancer
in eastern Anatolia. Hepatogastroenterology 49: 1290–1292
Ribeiro Pinto LF, Swann PF (1997) Opium and oesophageal cancer: effect of
morphine and opium on the metabolism of N-nitrosodimethylamine and
N-nitrosodiethylamine in the rat. Carcinogenesis 18: 365–369
Sewram V, De Stefani E, Brennan P, Boffetta P (2003) Mate consumption
and the risk of squamous cell esophageal cancer in Uruguay. Cancer
Epidemiol Biomarkers Prev 12: 508–513
Sharp L, Chilvers CE, Cheng KK, McKinney PA, Logan RF, Cook-Mozaffari
P, Ahmed A, Day NE (2001) Risk factors for squamous cell carcinoma of
the oesophagus in women: a case–control study. Br J Cancer 85(11):
1667–1670
Shephard GS, Marasas WF, Yazdanpanah H, Rahimian H, Safavi N, Zarghi
A, Shafaati A, Rasekh HR (2002) Fumonisin B(1) in maize harvested in
Iran during 1999. Food Addit Contam 19: 676–679
Sydenham EW, Shephard GS, Thiel PG, Stockenstro ¨m S, Snijman PW
(1996) Liquid chromatographic determination of fumonisins B1, B2,
and B3 in corn: AOAC-IUPAC Collaborative Study. J AOAC Int 79:
688–696
Wang H, Wei H, Ma J, Luo X (2000) The fumonisin B1 content in corn from
North China, a high-risk area of esophageal cancer. J Environ Pathol
Toxicol Oncol 19: 139–141
White E, Hunt JR, Casso D (1998) Exposure measurement in cohort studies:
the challenges of prospective data collection. Epidemiol Rev 20: 43–56
Feasibility of EC Cohort Study in Golestan Iran
A Pourshams et al
181
British Journal of Cancer (2005) 92(1), 176–181
& 2005 Cancer Research UK
Epidemiology