Yuki Obata

Serum insulin-like growth factor-I, insulin-like growth factor binding protein-3, and the risk of pancreatic cancer death

Recent epidemiological studies have shown that high serum levels of insulin‐like growth factor‐I (IGF‐I) are associated with an increased risk of lung, colon, breast and prostate cancer. Since very few studies have addressed the role of serum levels of IGF‐I in the development of pancreatic cancer, we conducted a nested case‐control study to examine this association. The analysis involved 69 case subjects who died from pancreatic cancer during the follow‐up period of the study, and 207 control subjects matched for sex, age(±1 year) and study area, selected randomly from a cohort of 10,364 individuals. Serum levels of IGF‐I and IGF binding protein‐3 (IGFBP‐3) were measured by immunoradiometric assay, using commercially available kits. The odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic models. The levels of IGF‐I were positively correlated with IGFBP‐3 (r=0.55). There was a positive, but statistically insignificant association between serum levels of IGF‐I and risk of death from pancreatic cancer, with subjects in the highest quartile having an OR of 2.31 (95% CI=0.70–2.64) compared to those in the lowest quartile. The risk of pancreatic cancer death increased significantly with increasing serum levels of IGFBP‐3 (trend p=0.03). Further adjustment for IGFBP‐3 or IGF‐I slightly attenuated the positive associations. This nested case‐control study showed that high serum levels of IGF‐I and IGFBP‐3 may be associated with an increased risk of death from pancreatic cancer.

Obesity, physical activity and the risk of pancreatic cancer in a large Japanese cohort.

It is unclear whether body mass index (BMI) and physical activity are associated with the risk of pancreatic cancer in Asian populations. We examined these associations in the Japanese Collaborative Cohort Study for Evaluation of Cancer Risk. Our cohort study included 110,792 Japanese men and women at enrollment (1988–1990). Data on height, body weight (at baseline and at age 20 years) and physical activity were obtained from a questionnaire. Cox proportional hazards models were used to estimate the relative risks of pancreatic cancer mortality. We observed a total of 402 pancreatic cancer deaths during the follow‐up period. Men with a BMI of 30 or more at age 20 years had a 3.5‐fold greater risk compared with men with a normal BMI. Women with a BMI of 27.5–29.9 at baseline had ∼60% increased risk compared with women with a BMI of 20.0–22.4. In men, weight loss of 5 kg or more between 20 years of age and baseline age was associated with an increased risk of pancreatic cancer death. In contrast, women with weight loss of 5 kg or more over the same period had a decreased risk. Physical activity was not associated with pancreatic cancer risk in either men or women. Obesity in young adulthood may be associated with an increased risk of death from pancreatic cancer in Japanese men. The risk of pancreatic cancer in relation to BMI seems to differ according to sex and the period over which BMI was measured.

Serum midkine concentrations and gastric cancer

Midkine (MK) is one of a family of heparin‐binding growth factors, and increased MK expression is reported in various types of human carcinomas. To clarify the association between serum MK (S‐MK) concentrations and gastric cancer, we examined S‐MK concentrations of gastric cancer patients (n = 275) and healthy controls (n = 275). S‐MK concentrations of all subjects were measured by enzyme‐linked immunosorbent assay (elisa). The medians (25th and 75th percentiles) of S‐MK were 192 (123 and 314) pg/mL in the cases and 170 (81 and 273) pg/mL in the controls (P < 0.01). We also compared S‐MK concentrations in each group divided by the progression stage or histological type of cancer. A difference was observed in the median S‐MK concentrations between early and advanced cancers [182 (105 and 301) pg/mL vs 203 (139 and 331) pg/mL, P = 0.07], but not between intestinal and diffuse type cancers [185 (121 and 306) pg/mL vs 198 (127 and 323) pg/mL, P = 0.51]. We found that those progression stages affect S‐MK concentration more strongly than the histological types in gastric cancer patients. Because S‐MK seems to reflect the progression stage of gastric cancer, it may serve as a useful marker in the clinical follow‐up of gastric cancer patients. (Cancer Sci 2005; 96: 54 –57)

Green tea consumption and the risk of pancreatic cancer in Japanese adults.

Objective: Green tea polyphenols have been shown to inhibit tumor growth in animal and in vitro studies. We examined the relationship between green tea consumption and the risk of death from pancreatic cancer in a large Japanese cohort. Methods: At baseline (1988-1990), study participants reported the frequency and amount of green tea consumption during the past year. They were followed-up for mortality until December 31, 2003. Relative risk and 95% confidence intervals were calculated from Cox proportional hazard models. Results: During an average follow-up of 13 years, we observed 292 pancreatic cancer deaths. In men and women combined, the relative risk was 1.23 (95% confidence interval, 0.84-1.80) for participants who consumed 7 or more cups of green tea per day as compared with those who consumed less than 1 cup per day, after adjustment for potential confounding factors. No significant trend in risk reduction was noted, with increasing consumption of green tea. We found no inverse association between cups of green tea consumed per day and the risk of pancreatic cancer in either men or women. Conclusions: Our findings do not support the hypothesis that green tea consumption is associated with decreased risk of pancreatic cancer in humans.

Dietary Habits and Pancreatic Cancer Risk in a Cohort of Middle-Aged and Elderly Japanese

Abstract: Few epidemiological studies have examined associations between diet and pancreatic cancer in Japan. In the Japan Collaborative Cohort Study for Evaluation of Cancer Risk, we evaluated the relationship between dietary factors, including meat, vegetable, and fruit intake, and the risk of pancreatic cancer deaths. Among the original cohort established between 1988 and 1990, 46,465 men and 64,327 women aged 40–79 yr were followed-up through December 31,1999. During 1,042,608 person-years of follow-up, we documented 300 deaths from pancreatic cancer. A 33-item food-frequency questionnaire was used to assess dietary intake at the baseline survey. Cox proportional-hazards models were used to estimate the relative risks of pancreatic cancer death in relation to the intake frequency of food items. We did not observe an overall association between meat intake and pancreatic cancer risk. Except for a 50% decrease in risk associated with high fruit intake among men, we did not find other significant inverse relationships between vegetable and fruit intake and pancreatic cancer risk. Smoking did not modify the associations with dietary habits. Our study suggested that high consumption of pickles and wild edible plants, mainly bracken, might be related to increased pancreatic cancer risk; however, this finding should be confirmed in other epidemiological studies.

Trends in the incidence of gastric cancer in Japan and their associations with Helicobacter pylori infection and gastric mucosal atrophy

BackgroundAlthough age-adjusted mortality from gastric cancer has been decreasing in Japan, the crude incidence of gastric cancer shows a slight increase.MethodsWe have observed trends in the incidence of gastric cancer by sex and 20-year age groups over the past two decades (1976–1996). Source data were obtained from the cancer statistics materials provided by the Research Group for Population-Based Cancer Registration in Japan. Simultaneously, we observed changes in the prevalence of Helicobacter pylori infection and in serological atrophy of the gastric mucosa, and compared the results with those involving changes in the incidence of gastric cancer.ResultsA slight decline was observed in all age groups over 40 years old, in both men and women, between 1986 and 1996. However, a marked decline in incidence was observed for those aged 20–39 years. The prevalence of H. pylori infection declined in both sexes between 1989 and 1998. The frequency of serological atrophy of the gastric mucosa significantly declined in all age groups between 1989 and 1996, with young age groups experiencing a more marked decrease.ConclusionThe marked decline in gastric cancer incidence observed in the young population will also begin to occur in the elderly population in the future.

Cigarette smoking, alcohol drinking and the risk of gallbladder cancer death: A prospective cohort study in Japan

Gallbladder cancer is a rare cancer with a poor prognosis, and few risk factors have been identified to date. This prospective study was conducted to evaluate the association of cigarette smoking and alcohol consumption with the risk of gallbladder cancer death. A baseline survey in 45 areas throughout Japan was conducted from 1988 to 1990 using a self‐administered questionnaire, and a total of 113,496 participants (65,740 women) aged 40–89 years at entry were followed for 15 years. During the follow‐up period, 165 gallbladder cancer deaths (95 women) were observed. Among women, the hazard ratio (HR) [95 percent confidence interval: 95% CI] of current smoker was 2.00 [0.91–4.42], when adjusted for age and drinking. There was no clear association between alcohol consumption and the risk. Among men, HR of current smoker was 2.27 [1.05–4.90]. HRs of those who smoked 21 cigarettes or more per day and those with 801–1,000 cigarette‐years were 3.18 [1.18–8.53] and 3.44 [1.40–8.45], respectively, and positive linear associations were observed between that risk and the number of cigarettes per day (p for trend = 0.007) or “cigarette‐years” (p for trend = 0.012). The alcohol dose was linearly associated with risk (p for trend = 0.004), where the HR among those who consumed 72.0 g or more of alcohol per day was 3.60 [1.29–9.85]. Among both men and women, cigarette smoking may elevate the risk of death from gallbladder cancer. Drinking may pose an elevated risk among men, but that seems to be less true among women.

Serum levels of transforming growth factor β1 are significantly correlated with venous invasion in patients with gastric cancer

Background and Aim:  The significance of serum levels of transforming growth factor (TGF)‐β1 in the development of gastric cancer is unclear. The purpose of this study is to determine whether serum TGF‐β1 correlated with the clinicopathological findings of patients with gastric cancer.

Association of menstrual and reproductive factors with pancreatic cancer risk in women: findings of the Japan Collaborative Cohort Study for Evaluation of Cancer Risk

BackgroundThe etiology of pancreatic cancer remains largely unknown. We examined the association of pancreatic cancer deaths with menstrual and reproductive factors in a cohort study involving Japanese women.MethodsA total of 63 273 women were followed up for mortality from 1988 to 1999. Information on menstrual and reproductive factors was obtained by a questionnaire survey at baseline. Cox proportional-hazards models were used to estimate the relative risks (RRs) and 95% confidence intervals (CIs) for death from pancreatic cancer in relation to menstrual and reproductive factors.ResultsDuring 631 401 person-years of follow-up, 154 women died from pancreatic cancer. Parity was not significantly associated with the risk of death from pancreatic cancer; the RR was 0.80 (95% CI, 0.31–2.11) for women with six or more births compared with women with zero or one birth. We found no significant overall association with other reproductive factors, including pregnancy, age at first birth, and menopause. The risk appeared to increase with increasing age at menarche; the RR was 1.49 (95% CI, 0.95–2.34) for women who had menarche after 16 years of age compared to those who had menarche before they were 15 years old.ConclusionsOur prospective data indicate that menstrual and reproductive factors are not associated with the risk of death from pancreatic cancer among Japanese women.

Serum Copper/Zinc Superoxide Dismutase (Cu/Zn SOD) and Gastric Cancer Risk: a Case‐Control Study

We conducted a case‐control study to evaluate the association between serum levels of copper/zinc superoxide dismutase (Cu/Zn SOD) and the risk of gastric cancer. Cases were 214 patients who had been diagnosed with gastric cancer and controls were 120 persons who underwent medical checkups. Serum levels of Cu/Zn SOD were determined by enzyme‐linked immunosorbent assay (ELISA). Compared with the lowest quartile, the OR (odds ratio) was 4.54 (95% CI (confidence interval), 1.62–12.66) for the third quartile and 15.75 (95% CI, 5.84–42.46) for the highest quartile. With both early and advanced cancers, as well as with the intestinal and diffuse types, a significant increase in risk was observed with increasing levels of serum Cu/Zn SOD. Our case‐control study showed that serum levels of Cu/Zn SOD were significantly elevated in gastric cancer patients compared with apparently healthy controls, and higher Cu/Zn SOD levels may be associated with an increased risk of gastric cancer.