Cancer epidemiology in mainland South-East Asia - past, present and future.

The countries of mainland South-East Asia, Myanmar, Thailand, Laos, Cambodia and Viet Nam, share a long history of interactions and many cultural similarities, as well as geographical contiguity. They therefore can be usefully examined as a group when considering measures for control of cancer and other non-communicable diseases. Liver cancer is consistently found at higher incidence than most other parts of Asia, with lung cancer as the other most important neoplasm in males. In females cervical and breast cancer about equally predominate, throughout. However, there are also major differences, particularly with regard to stomach and nasopharyngeal cancer, only found at relatively high incidence in Viet Nam. The present review was conducted to gather together registry data on cancer prevalence and epidemiological findings cited in PubMed in order to obtain as comprehensive picture as possible of the present status. It is hoped that future cooperation across the region will facilitate development of coordinated cancer control programs to reduce the burden.

Cross-reactivity between immune responses to Helicobacter bilis and Helicobacter pylori in a population in Thailand at high risk of developing cholangiocarcinoma.

Helicobacter bilis DNA has been detected in human tissue and is a candidate for etiologic investigations on the causes of hepatic and biliary tract diseases, but reliable serologic tests need to be developed in order to pursue such investigations. The scope of this study was to assess the specificity of two assays for H. bilis immune response allowing for H. pylori, and their cross-reactivity in a population in Thailand at high risk for cholangiocarcinoma. Plasma samples from 92 Thai volunteers were independently tested in two laboratories (Massachusetts Institute of Technology [MIT] and Lund). MIT performed three analyses of H. pylori and H. bilis based either on (i) outer membrane protein (OMP) with no preabsorption or on antigens derived from whole-cell sonicate before (ii) or after (iii) preabsorption with H. pylori sonicate protein. Lund used cell surface proteins from H. pylori and H. bilis as antigens. Testing for H. bilis was preabsorbed with a whole-cell lysate of H. pylori. More than 80% of the samples were positive for H. pylori in both laboratories. As tested by MIT, 58.7% (95% confidence interval, 47.9 to 68.9%) were positive for H. bilis by OMP and 44.5% (34.1 to 55.3%) were positive for H. bilis sonicate protein, but only 15.2% (8.6 to 24.2%) remained positive after preabsorption with H. pylori sonicate protein. Lund found 34.5% of the samples positive for H. bilis (22.0 to 41.0%), which was statistically compatible with all three MIT results. Serologic responses to OMPs of the two bacteria coincided in 66 and 45% of the samples in the MIT and Lund assays, respectively. We found high cross-reactivity between the immune responses to H. pylori and H. bilis antigens. More-specific H. bilis antigens need to be isolated to develop serologic tests suitable for epidemiological studies.

Lifestyle-related risk factors for stomach cancer in northeast Thailand.

BACKGROUND: Stomach cancer is not common in Thailand but the life styles of the Thai population are changing to become more Western so that information for planning control programme of stomach cancer is necessary. The highest incidence rates of this neoplasm are found in Eastern Asia, ranging from age-standardized rates of 95.5/105 (men) and 40.1/105 (women) in Yamagata, Japan to 4.1/105 (men) and 2.1/105 (women) in Khon Kaen, Northeast of Thailand. In Thailand, the estimated age-standardized incidence rates in 1993, 1996 were 4.9/105, 4.1/105 in men and 3.0/105 , 2.6/105 in women. Risk factors for stomach cancer in Thai population are unclear, but possibly include low intake of vegetables and fruits, alcohol drinking, tobacco smoking and high intake of salt. OBJECTIVE: To investigate various aspects of dietary factors, smoking, and alcohol drinking in determining risk of stomach cancer in Thai population. METHODS: A case-control study was conducted in Khon Kaen, Thailand during 2002-2006, to study the role of these factors in stomach cancer. 101 stomach cancer cases and 202 matched controls (case : control = 1:2) by sex, age (? 3 years) and region were recruited from Srinagarind Hospital and Khon Kaen Regional Hospital, in Khon Kaen Province. All of cases were histologically confirmed. Controls had a variety of diseases, the main ones being disease of the eye. Information on dietary habits, alcohol drinking and smoking were collected by a structured questionnaire, blood samples were collected for further study. RESULTS: The distribution of the general characteristics by case-control status, the distribution of age and sex were similar in cases and controls. In the final analysis, the factors that found to be higher risk but not statistically significant were long-term filter cigarette smoking (OR=1.9, 95%CI: 0.85-4.50), long-term alcohol consumption (OR=1.2, 95%CI: 0.51-2.60) and low intake of vegetables and fruits (OR=1.2, 95%CI: 0.74-1.96). A high intake of vegetable oil (OR=4.5, 95%CI: 1.00.-20.17) was found to be associated with increased risk, and similar tendencies were noted for pork oil (OR=1.4, 95%CI: 0.63-3.01) and jeaw prik (mainly chilly with plara broth) (OR=1.2, 95%CI: 0 .76- 2.01). CONCLUSION: Our study confirmed protective effects of a high intake of fruits and vegetables against stomach cancer development and showed a high intake of sauces to increase risk of stomach cancer as in other countries in Asia.

Use of lay health workers in a community-based chronic disease control program.

The increasing burden of non-communicable diseases in the developing world, and in particular diabetes, cancer and circulatory diseases, is an unfortunate fact of life. At the same time infection-related diseases, including sexually transmitted HIV-AIDS and HPV-dependent cervical cancer, remain important. One approach to alleviating the resultant stress on national health provision is to expand the knowledge base at the community level with contributions by lay health workers (LHWs). Here we take a brief look at the available literature and propose a model for intervention incorporating two way dialogue with the general populace to find effective means to package expertise in the medical/research community for lay consumption. Our argument is that particular attention should be paid to socioeconomic and behavioural aspects and to disease surveillance at the local level in order to be able to accurately assess the impact of interventions. For this purpose, we need to marshal volunteers from within communities taking account of their problems and motivations. Included are provision of assistance in setting up physical exercise programs, quit tobacco campaigns, alcohol awareness programs, running disease screening exercises and general help by providing advice as to risk and protective factors and clinical treatments, with an special focus on palliative care.

Evaluation of primers and PCR performance on HPV DNA screening in normal and low grade abnormal cervical cells.

High risk human papillomaviruses (HR-HPVs) are associated with increased risk of normal cervical cells developing to dysplasia and cervical carcinoma. Therefore, HR-HPV DNA testing can predict an endpoint of cervical carcinogenesis that is earlier than the development of cervical abnormalities. Not only the sensitivity of methods but also the amount of HPV DNA are very important and might be parameters to distinguish HPV detection. In this study, we evaluated the effects of primer sets and the polymerase chain reaction (PCR) performance with low viral load samples with normal cervical cytology (140 samples) and mild dysplasia (140 samples) using two consensus primers MY09/MY11 and GP5+/6+. The PCR was performed with single and nested PCR. Positive samples with both primer sets were then HPV genotyped by dot blot hybridization. Results showed higher sensitivity of single PCR using primer GP5+/GP6+ than primer MY09/MY11. HPV DNA was detected in 15% (21 of 140)and 20.7% (29 of 140) of normal cervical samples, respectively. For mild dysplasia samples, HPV DNA was detected in 37.1% (52 of 140) with MY09/MY11 and 50% (70 of 140) using GP5+/GP6+. In normal cervical samples, the positivity rate was increased to 38.5% (54 of 140) by nested PCR using primer GP5+/6+, but only 2 mild dysplasia samples that were negative by single GP5+/6+ were positive by auto-nested PCR. These results suggested that, in low viral load samples, the sensitivity of HPV DNA detection depends not only on primer sets but also PCR performance. HPV 16 was the most common in mild dysplasia samples (20.8%), whereas HPV type 58 was found in 11.1%. This study suggested that nested PCR might be necessary for HPV DNA detection in cervical samples of women participating in cervical cancer screening.

Factors affecting survival of cervical cancer patients treated at the radiation unit of Srinagarind Hospital, Khon Kaen University, Thailand.

This retrospective longitudinal study aimed to evaluate factors for survival of cervical cancer patients treated with radiation therapy. Information was retrieved from the medical records of 1,180 cervical cancer patients and pathologic material was reviewed to confirm the diagnosis who treated with radiation therapy at Srinagarind Hospital, Khon Kaen University between 1 January 1994 to 31 December 1999. And they were followed up until December 31, 2004. The patients current vital status was searched through hospital-based registry, the population-based cancer registry of Khon Kaen Province, the civil registration database, the Ministry of Interior and mails were sent to them. Data were analysed with the Kaplan-Meier, Log-rank test and Cox proportion hazard model. Results were found that mortality rate of 70 per 1,000 person-year. The overall 5-years survival rate was 62.5%. Median time survival was <10 years. From multivariate analyses, the factors that were statistically affected survival of cervical cancer patients included staging (p-value<0.001), hemoglobin level (p-value<0.001), interval between external and intracavitary radiation (p-value<0.001) and fractionation (p-value=0.024). Stage III was the most important risk factors of mortality risk with 1.65-fold mortality risk compared with stage I (95% CI=1.05-2.59). Patients with low hemoglobin level (< or = 10 g./dl.) was associated with 1.85-fold mortality risk compared with patients who had level >12 g./dl. (95% CI=1.40-2.44). The interval between external and intracavitary radiation >28 days was associated with 2.28-fold mortality risk compared with patients who had duration <1 day (95% CI= 1.40-2.44). The fractionation 2 faction was associated with 0.25-fold mortality risk compared with 1 fraction (95% CI=0.07-0.96). The results of study show that stage of disease, hemoglobin level, interval between external- intracavitary radiation and fractionations were factors affected survival cervical patients treated with radiation. Future prospective trials should be undertaken to confirm the validity of these factors and to elucidate their therapeutic implications.

Pap smear, colposcopy and biopsy findings at follow-up of Pap smear positive women in North-east Thailand.

As part of an ongoing project involving a large cohort in the Khon Kaen Province in the North-east of Thailand, a total of 236 women who had tested positive for a Pap smear at the initial recruitment and advised to seek medical attention were followed up after a mean period of 3.1 years. The 204 individuals who could be contacted were interviewed to determine treatments received and underwent a further Pap smear as well as colposcopy in 179 of the cases. On clinical advice, biopsies were also taken from 32 of these. Only 15% of the total of 204 had actually received therapy, the majority undergoing surgery (self-reported). Possible positive Pap smear results were obtained for 23.5%, with 6.4% having high grade squamous intraepithelial lesions (HGSILs) or squamous cell carcinoma (SCC) (one case). Comparison of the different testing modalities demonstrated 5.6% false negatives and 16.2 false positives for the Pap smear with colposcopy as the gold standard. Compared with biopsy findings, there were 21.8% and 40.6% false positives with Pap and colposcopy, respectively, but no false negatives. The present results point to good efficacy for the initial screening, since only 0.5% of the total population developed an SCC. However, judgement as to therapy should depend on a biopsy since there were considerable false positives with the other two modalities employed.

Risk factors for colorectal cancer in northeast Thailand: lifestyle related.

BACKGROUND: The incidence of colorectal cancer is variable around the world. Hiroshima, Japan had the highest incidence in men in 1997 with an age-standardized rate of 86.7 per 100,000 and New Zealand had the highest, at 40.6 per 100,000, in women. The incidence of colorectal cancer in Thailand is rather low and the latest figures for Northeast of Thailand are 7.1 per 100,000 for men and 4.7 for women. The reasons for these differences between countries are possibly due to variation in dietary habits, alcohol drinking or other cofactors. METHODS: A case-control study was conducted in Khon Kaen, Northeast Thailand during 2002-2006 to study risk factors for colorectal cancer in a low risk area. Totals of 253 colorectal cancer cases (males 135, females 118) and 253 age- and sex-matched controls were recruited. Information on dietary habits, alcohol drinking, smoking and other information were collected by a structured questionnaire. Blood samples were collected for further study. Both univariate and multivariate analyses were carried out. RESULTS: In the final model of multivariate analysis, the significant risk factors for colorectal cancer were a family history of cancer (OR=1.9 95%CI=1.2-2.9) and meat consumption (OR=1.0 95%CI=1.0007-1.0026). For BMI, subjects with higher BMI unexpectedly had a lower risk of colorectal cancer (OR=0.5 95%CI=0.3-0.8). CONCLUSION: Our study confirmed risk factors for colorectal cancer i.e. meat consumption and cancer in the family (genetic problem). However, the results for BMI are the reverse of expected, underlining one limitation of hospital-based case-control studies, in which cases are ill and admitted to the hospital at late stage.

Ultrasound screening for Opisthorchis viverrini-associated cholangiocarcinomas: experience in an endemic area.

In Thailand, liver cancer is the most common malignancy in males and the third most common among females. In the Northeast region, cholangiocarcinoma (CHCA) is the prevalent type, with Opisthorchis viverrini (OV), an endemic liver fluke, being considered the cause. We evaluated the role of ultrasound (U/S) for cholangiocarcinoma screening as part of a larger cohort to characterize the linkage between liver fluke infestation and CHCA in Khon Kaen (Northeast Thailand). Most people (77%) had normal U/S findings while only 0.5% had suspected CHCA; thus, U/S should be used primarily for those with the highest risk, presenting symptoms and/or being OV positive.

Usefulness of combining testing for p16 protein and human papillomavirus (HPV) in cervical carcinoma screening.

OBJECTIVE: To evaluate the value of the combination of p16 and HPV detection in the screening for cervical cancer. METHODS: 186 patients with previous abnormal cervical lesion were studied. After colposcopic examination, two conventional Pap slides were prepared: the first was Papanicolaou-stained and examined by cytologist; the second was immunocytochemically stained for p16. Cervical cells were collected by brush using for HPV detection by Hybrid Capture II. Biopsy of any colposcopically abnormal lesions was performed. RESULTS: The 186 cervical samples were classified cytologically as normal (148), ASCUS (13), low-grade (11), high-grade (12) dysplasia and squamous cell carcinoma (2). P16 and HPV were found in all high-grade dysplasia and SCC, and in 64% and 27% of low-grade dysplasia, 62% and 0% of ASCUS and 7.4% and 3.4% of normal, respectively. 18 of p16-positive cases (11%) were HPV-negative, 14 of them in the ASCUS and normal group. Compared to histological results, all of the p16-positive cases of squamous metaplasia, CIN II/III and SCC were HR-HPV-positive. Therefore, the cases that were positive for both with normal cytology (5 cases) or low-grade dysplasia (3 cases) may comprise a high-risk group for neoplastic change. CONCLUSION: The combination of p16 and HPV detection may be useful in cervical cancer screening to identify high-risk patients requiring early and proper management.

Cervical cancer screening in Thailand: an overview.

In Thailand, there have been no 'organized' programmes of screening for cervical cancer. For the most part, screening has been unsystematic or provided to women 'on demand'. In 2002, the Department of Medical Services of the Ministry of Public Health proposed the screening of the entire population of women in Thailand at 5-yearly intervals from the ages of 35 to 60 years. As a first step, measures to increase the capacity for obtaining and interpreting papanicolaou (Pap) smears have been put in place. Research studies have examined the effectiveness of screening with Pap smears in Thailand, and confirmed that, as elsewhere, protection is related to the number of previous tests and the time elapsed since the most recent one. Coverage of the population remains low. Other methods of screening are being investigated in Thailand, including visual inspection following acetic acid (VIA), followed by immediate treatment of observed lesions by cryotherapy ('see and treat'). Other research studies have examined the acceptability and performance of self-sampling as a means of obtaining Pap smears, and the use of mobile clinics to increase coverage of at-risk women in rural settings. Human papillomavirus (HPV) testing has been used to identify high-risk women, or to help decide which women with low-grade abnormality on cytology should undergo more intensive follow-up. Prevalence of HPV in normal women in Thailand is 9-20%, but HPV testing has not been used on any systematic basis to date. Current screening programmes in Thailand are not very effective. The national cancer control programme aims to increase the coverage of screening. The population-based cancer registry will provide an effective and economical method of evaluating the impact of early diagnosis and screening at community level.

Trends in incidences of stomach and colorectal cancer in Khon Kaen, Thailand 1985-2004.

BACKGROUND: The life styles of Thai people are changing with westernization and this would be expected to have an impact on the prevalence of cancer and other non-communicable diseases. For planning control programmes it is necessary to monitor change over time and the present study was conducted to provide information on stomach and colorectal cancer incidence rates in Khon Kaen Cancer Registry (KKCR), established in 1984 at the Faculty of Medicine, Srinagarind Hospital, Khon Kaen University. OBJECTIVE: To assess trends in urban and rural areas of Khon Kaen province during 1985 - 2004. METHODS: Data for stomach and colorectal cancer with an ICD-O diagnosis (coding C16 , C18 - C20) from the population-based cases of the KKCR, registered between 1985 and 2004, were retrieved and incidence trends were calculated using the Generalized Linear Model method (GLM), which generates incidence-rate-based logarithms. RESULTS: The study population comprised 2,530 cases, 721 of stomach (males 449, females 272) and 1809 of colorectal (males 976, females 833) cancer. Most cases were aged 35-75 years. According to the histopathological diagnosis, the most common was adenocarcinoma with over 90 percent. The overall age-standardized incidence rates (ASR) for stomach cancer were 4.5 and 1.4 per 100 000 in males and females, respectively, during 1985-1989, 3.7 and 2.0 during 1990-1994, 3.0 and 2.2 during 1995-1999 and 3.6 and 1.8 during 2000-2004 . The respective figures for colorectal cancer were 3.3 and 2.6, 4.6 and 3.1, 5.4 and 3.5 and finally 5.8 and 5.3. In both urban and rural areas males were affected more frequently than females, although a shift was evident towards decrease in the se ratio was evident for colorectal cancers over time. DISCUSSION: The results of this study showed slight increase in the incidence of colorectal cancer in Khon Kaen province, while rates for stomach cancer remained quite stable. The findings indicate a need for continuing research in stomach and colorectal cancer epidemiology, with subdivision into particular sites within these two sections of the gut.

A prospective study of diet, lifestyle, and genetic factors and the risk of cancer in Khon Kaen Province, northeast Thailand: description of the cohort.

Cohort studies are the preferred design in observational epidemiology, but few involving the general population have been performed in Asia, and most concern affluent urban populations. The Khon Kaen study has recruited about 25,000 subjects, aged mainly 35-64, from villages in the relatively underdeveloped north-east of Thailand. All subjects underwent simple physical examination, completed an interviewer-administered questionnaire (including sections on lifestyle, habits, and diet) and donated specimens of blood, which were processed and stored in a biological bank at -20 degrees C. Female subjects (about 16,500) were offered screening by Pap smear, and specimens of cells from the cervix were stored at -20 degrees C. This paper describes the methodology of the study, and the characteristics of the participants. Almost all subjects are peasant farmers, with low annual income and body mass, although 14.6% of women had a BMI in the obese range (>30 kg/m(2)). Smoking was common among men (78% regular smokers, most of whom used home-produced cigarettes), but rare among women. Fertility levels were relatively high, with a more than half the women having four or more live births. 23.4% of subjects were infected with the liver fluke Opisthorchis viverrini, known to be highly endemic in this region. Follow-up of the cohort is by record-linkage to the provincial cancer registry. By 2003, 762 cancer cases had occurred, the most common being cancers of the liver (363 cases) and cervix uteri (44 cases). The antecedents of these cancers are being investigated using a nested case-control approach. The cohort will yield increasing numbers of cancers for study in the next decade, giving important information on the relative importance of dietary and lifestyle factors in a rural population, undergoing gradual transition to a more westernised lifestyle.

Consistency of cytology diagnosis for cervical cancer between two laboratories.

The principal approach to the prevention of cancer of the cervix uteri has been through screening programmes, using the cervical smear (Pap test) to detect precursor lesions. The sensitivity and specificity of Pap smears depend on the skill of the observer in recognizing and classifying a variety of cellular abnormalities. We have studied the reproducibility of cytological diagnosis, according the Bethesda classification, made by cytologists in Khon Kaen, north-east Thailand, and in Helsinki, Finland, on smears taken from rural women undergoing screening during 1994-2001. A total of 313 slides were reviewed. The prevalence of abnormalities was relatively high, since the series included smears judged abnormal in Khon Kaen or from women who developed cancer during follow-up, as well as a group whose smears were negative. In general, the reviewing cytologist in Finland evaluated more slides as abnormal than in the initial report. The level of agreement between the two observers was evaluated by calculating the coefficient of concordance (Kappa). The kappa score depended upon the degree of detail in the diagnosis; it was 0.43 for the presence or not of an epithelial abnormality (the General Categorization of the Bethesda system), and rather higher (0.5) for separating low grade from high grade (HSIL or worse) abnormalities or glandular lesions. Agreement was only fair (0.37) when the more detailed Bethesda categories (seven) were used. The reproducibility of cervical cytology evaluations is critical to the success of screening programmes, and in this programme in a moderate-high risk population of women in rural Thailand, we found that agreement between skilled observers, at the level of tests requiring diagnostic follow-up or not, was only moderate. The women in this study are being traced to evaluate the true sensitivity of screening in terms of the lesions found on histology, during a prolonged follow up of 4 or more years.

Behavioural risk factors for cervical cancer from a prospective study in Khon Kaen, Northeast Thailand.

Fifty seven cases of cancer of the cervix were identified within a cohort of 16,648 women enrolled in a cohort study of lifestyle and cancer in a rural population of Northeast Thailand. They were compared with 228 matched controls from the same cohort, with respect to demographic, behavioural and reproductive factors potentially associated with risk of the disease. Number of pregnancies and age at having first child were associated with the risk of cervical cancer, but in contrast to studies elsewhere, age at having first sexual intercourse, number of sexual partners and sexually-transmitted infections were not associated with risk. The lack of effect may be simply due to the small size of the study. But it is also likely that these aspects of female sexual behaviour are not very relevant in a relatively conservative rural population. These aspects may be investigated further in future, as new incident cancers are accrued into the cohort.

Experience with a self-administered device for cervical cancer screening by Thai women with different educational backgrounds.

BACKGROUND: This descriptive study was carried out to test the acceptability of a self-administered device for cervical cancer screening and assess certain risk factors in relation to the cancer in two districts of Khon Kaen province in Northeast Thailand. METHODS: A total of 354 women from the villages were selected (including 143 teachers from secondary and primary schools; 24 health officers from the rural health centres, and 37 nurses from the University Hospital, Khon Kaen University). The Kato device was introduced and used by the women, who were then asked to give their opinion on its usage. RESULTS: The Kato device was generally well accepted by the women. However, many of those with a higher educational background were more sceptical towards the device than their counterparts from the villages. CONCLUSIONS: A suitable approach to strengthen the control of cervical cancer in the rural areas of Thailand might be to introduce the Kato device as an integral part of primary health care. The introduction of the device should go along with health education on the importance of avoiding infection with the papilloma viruses. This message should be transmitted to both females and males.

Serum gamma-glutamyl transpeptidase and alkaline phosphatase of people in Khon Kaen, the northeastern Thailand.

Serum gamma-glytamyl transpeptidase (GGT) and alkaline phosphatase (ALP) of the normal population in Northeastern Thailand were measured. The median serum GGP and ALP levels of females was significantly lower than the values for males, i.e., 21 (range=9-260) versus 32 (range=9-459) and 73 (range= 20-428) versus 83 (range=13-171) U/L, respectively. Serum ALP level tended to increase with age in both male and female populations, whereas serum GGT level did not show any age dependence. Serum GGT and ALP levels of cigarette smokers were significantly higher than those of the non-smokers. Alcohol, coffee or tea drinking also resulted in higher serum GGT value whereas serum ALP values were not changed. Beta l nut chewing caused only lower serum GGT but not serum ALP values. The total population in Ban Fang district seemed to have lower serum GGT than those in Chonnabot district. The results from our study give the base line data of serum GGT and ALP in a Thai population. We also confirm the association of serum GGT with cigarette smoking, alcohol and coffee/tea drinking which are risk factors of cancer.

The coverage of cervical cancer screening in Khon Kaen, northeast Thailand.

Cervical cancer is a common cancer in Thai women and one of the only cancers that can be readily cured if early detection is successful. The Pap smear is an accepted as an appropriate means for cervical cancer screening at present. However, there are still some management problems with early detection programmes. Since data showing how many women have been screened by Pap smear are limited in Thailand, the present study was conducted with the aim of determining coverage in a defined population in the sample area, Thakaserm sub- district in Nampong district, Khon Kaen province, Thailand. The investigation was carried out during June-August 2000 to collect information on history of screening for cervical cancer using questionnaires. All women aged 20 and above were asked to answer the set of questionnaires a total of 1199 women responded. There were 66.9% that reported having received a Pap smear test for screening for cervical cancer at least once. However, there were 33.1 % that had never undergone a Pap smear in their life. It is important to find a strategy to increase the coverage of cervical cancer screening programme for this population.

Serum antioxidant vitamin levels of people in Khon Kaen, northeastern Thailand.

Three antioxidant vitamins, the alpha- and beta-carotenes as well as vitamin E, were measured in sera of a normal population in Northeastern Thailand using HPLC. The mean serum beta-carotene level of females was significantly higher than the value for males, i.e, 37.55 (95%CI=34.59-40.51) versus 32.97 (95% CI=30.01-35.93) micro/dl. The beta-carotene level tended to decrease as age increased, particularly in the male population. The mean serum beta-carotene level was also higher in females than in males, i.e., 7.08 (95%CI=6.57-7.59) and 6.26 (95% CI=5.77-6.75) micro/dl, respectively. The average serum alpha-tocopherol (Vitamin E) level of the whole population was 1.08 (95% CI=1.04-1.12) micro/dl and did not show age or sex differences. In general, the serum antioxidant vitamins of smokers were lower than those of the non-smokers but a significant difference was observed only for alpha-tocopherol. Alcohol drinking resulted in slightly lower serum beta-carotene values, whereas coffee or tea drinking and betel nut chewing did not cause any differences with these three antioxidant vitamins. However, we report higher in serum beta-carotene levels of people in Ban Fang district than in Chonnabot district. The results from our study give the base line data of serum antioxidant vitamins in a Thai population and also suggest future intensive study on the relationship of dietary intake and cancer prevention.