Biomedical subjects

Norihiko Hayakawa

Publications and source records attributed to Norihiko Hayakawa.

At least 19 recordsLinked to original sources

PubMed2006

Effectiveness of cervical cancer screening over cervical cancer mortality among Japanese women.

BACKGROUND: Various studies have revealed that cervical cancer (CC) screening significantly reduces both CC incidence and mortality in developed countries. Although Japan introduced a nationwide government funded annual CC screening for the women aged 30+ in 1982, the effectiveness of CC screening on CC mortality has not yet been evaluated by any prospective cohort study. Therefore, the present study evaluated the association of CC mortality with self-reported CC screening and some other factors by a nationwide cohort study. METHODS: Baseline survey of the Japan Collaborative Cohort Study for the enrollment of subjects was completed during 1988-90 and followed until 2003. This study only analyzed 63,541 women, aged 30-79 years, who were free from any cancer history at enrollment. RESULTS: During the follow-up period, 38 CC deaths were identified. The mean age at mortality was 67.0 years, with a mortality rate of 4.2 per 100,000 person-years. Participation rate in CC screening was 46.9%. Age-adjusted Cox model indicated significantly lower CC mortality [hazard ratio (HR) = 0.30, 95% confidence interval (CI) = 0.12-0.74] due to CC screening. Protectiveness remained almost the same (HR = 0.30, 95% CI = 0.12-0.76) when adjusted for age, body mass index and number of deliveries. The results also revealed that CC screening could reduce at least 50% of CC deaths even after excluding the effect of possible self-selection bias. CONCLUSIONS: CC screening in Japan may reduce CC mortality significantly for women aged 30-79 years. However, further studies with more CC deaths and increased statistical power are needed to validate the findings.

Adult↗

PubMed2005

Leptin is associated with an increased female colorectal cancer risk: a nested case-control study in Japan.

OBJECTIVE: To elucidate whether leptin is involved in the etiology of female colorectal cancer. METHODS: A case-control study nested in the Japan Collaborative Cohort Study. We compared serum leptin levels in 58 cases of female colorectal cancer with those in 145 controls matched for study area and age. Data were analyzed using a conditional logistic regression model with adjustments for known risk factors for the development of colorectal cancer. Quintile cutoff points were determined on the distribution of leptin levels in cases and controls combined. RESULTS: Serum geometric mean levels of leptin were 6.88 ng/ml in cases and 6.00 ng/ml in controls. The odds ratios of female colorectal cancer risk were 1.40 (95% confidence interval, CI: 0.41-4.78) for the category of the second and third quintiles combined, and 4.84 (CI: 1.29-18.1) for the category of the fourth and fifth quintiles combined relative to the first quintile after adjustment for body mass index (BMI), life-style factors, reproductive factors, and hormonal variables including insulin-like growth factor and its binding protein. CONCLUSION: Our results suggest that leptin most likely increases the risk of female colorectal cancer substantially independent of BMI.

Adult↗

PubMed2005

Serum levels of polyunsaturated fatty acids and risk of colorectal cancer: a prospective study.

To examine the relation between serum fatty acids and risk of colorectal cancer, the authors conducted a nested case-control study of 169 colorectal cancer cases and 481 controls matched by age and enrollment area as part of the Japan Collaborative Cohort Study. Serum samples were donated by subjects at baseline (between 1988 and 1990) and were stored at -80 degrees C until 2002. Serum fatty acid levels were measured by using gas chromatography and were expressed as the weight percentage of total lipids. Conditional logistic regression analyses adjusted for lifestyle factors revealed that total omega-3 polyunsaturated fatty acids (odds ratio = 0.24, 95% confidence interval: 0.08, 0.76), alpha-linolenic acid (odds ratio = 0.39, 95% confidence interval: 0.16, 0.91), docosapentaenoic acid (odds ratio = 0.30, 95% confidence interval: 0.11, 0.80), and docosahexaenoic acid (odds ratio = 0.23, 95% confidence interval: 0.07, 0.76) all showed a significantly decreased risk for the highest versus the lowest quartile levels for colorectal cancer in men. For women, a weak negative association was observed between docosapentaenoic acid and colorectal cancer risk, although it was not statistically significant. No adverse effects of high serum levels of omega-6 polyunsaturated fatty acids on colorectal cancer risk were detected.

Adult↗

PubMed2005

Serum carotenoids, retinol, and tocopherols, and colorectal cancer risk in a Japanese cohort: effect modification by sex for carotenoids.

To examine associations of serum carotenoids, retinol, and tocopherols with colorectal cancer risk, we conducted a case-control study nested within the Japan Collaborative Cohort Study. These micronutrients were measured in prediagnostic serum samples from 116 men and women who developed colorectal cancer during an 8-yr follow-up period and from 298 matched controls. In men, the higher level of serum total carotenoids was associated with a decreased risk: The multivariate-adjusted odds ratio (OR) for the highest vs. the lowest tertile was 0.34 (95% confidence interval [CI] = 0.11-1.00; trend P over tertiles = 0.040). In women, the higher levels of alpha- and and total carotenoids were instead related to an increased risk: The corresponding ORs were 4.72 (95% CI = 1.29-17.3), 2.00 (0.70-5.73), and 2.47 (0.73-8.34), respectively (trend P = 0.007, 0.040, and 0.064, respectively). We also found a somewhat decreasing risk with increased serum retinol in all subjects and alpha-tocopherol in men: The ORs (95% CI) for the highest tertiles were 0.29 (0.11-0.78; trend P over tertiles = 0.010) and 0.29 (0.07-1.17; trend P = 0.098), respectively. The effects of some carotenoids on colorectal cancer risk may be modified by sex or by factors associated with sex, including smoking and drinking habits.

Adult↗

PubMed2005

Green tea and stomach cancer--a short review of prospective studies.

BACKGROUND: In Japan, green tea has been drunk for a long time. Because it can be drunk casually, many people love drinking it. If such green tea has an effect to prevent stomach cancer, it will be a very convenient way to prevent the disease. METHODS: To examine the association between green tea consumption and the risk of stomach cancer, past epidemiologic studies including JACC Study were reviewed. RESULTS: Among eight case-control studies, five showed risk reduction with a statistically significant difference, and two studies showed risk reduction without a statistically significant difference. The remaining study showed the opposite result. Among six prospective studies regarding stomach cancer, no study showed risk reduction with a statistically significant difference. Four of the six studies showed no relation. In terms of study design, prospective studies, which are considered to be more reliable than case-controlled studies, tend to show no risk reduction. The results of case-control studies and prospective studies present considerably different impressions. CONCLUSIONS: Prospective studies showed no inverse association between the consumption of green tea and the risk of stomach cancer.

Beverages↗

PubMed2005

Serum levels of insulin-like growth factor I, II, and binding protein 3, transforming growth factor beta-1, soluble fas ligand and superoxide dismutase activity in stomach cancer cases and their controls in the JACC Study.

BACKGROUND: The prognosis of stomach cancer with advanced stage remains poor. New biomarkers of the disease that may contribute to establish the potential screening strategy would be of value for the early detection of individuals at high risk of the disease. METHODS: We conducted a prospective, nested case-control analysis among apparently healthy men and women who were followed for up to 8 years in the Japan Collaborative Cohort (JACC) Study, to evaluate serum levels of insulin-like growth factor I, II, and binding protein 3 (IFG-I, IGF-II, and IGFBP-3), transforming growth factorbeta-1 (TGFbeta1), soluble fas (sFas) and superoxide dismutase activity (SOD) in 210 stomach cancer cases diagnosed in the JACC Study in relation to those levels in their 410 controls. RESULTS: Among 6 serum biomarkers tested for case-control differences, only sFas level in female stomach cancer cases was significantly higher than that of controls (2.22 pg/ml vs. 2.04 pg/mL, respectively; P=0.013 by two-way analysis of covariance controlling for matching variable). CONCLUSION: None of the biomarkers consistently predicted future risk of stomach cancer in both men and women in the present analysis. Serum sFas level in women, however, should be studied much more thoroughly whether it provides meaningful refinement of risk stratification, or it elucidate the mechanisms of tumorigenesis in women.

Adult↗

PubMed2005

Serum pepsinogen values and Helicobacter pylori status among control subjects of a nested case-control study in the JACC study.

BACKGROUND: Helicobacter pylori infection and serum pepsinogen values are strongly related with stomach cancer. The aim of this study was to know what were these factors among general population. METHODS: Subjects were randomly selected 633 control subjects in a nested case-control study for risk of stomach cancer. Most of them were from rural areas of Japan. Using frozen sera, pepsinogen I (PG I) and II (PG II) values and H. pylori antibody were measured. Those with PG I less than 50 ng/mL and the ratio of PG I to PG II (PG I/II) was less than 2.0 were defined as severe, those with PG I less than 70 ng/ml and PG I/II less than 3.0 were defined as mild and the other subjects were defined as no serological atrophy. RESULTS: About 70% of the subjects were H. pylori seropositive and the seroprevalence did not depend on age or sex. Percentages of those with severe serological atrophy increased with age from 10% in those aged 40-49 years to 38% in 70 and more, and percentages of those with mild serological atrophy were about 30% independent of age. CONCLUSIONS: The subjects, who were expected to represent populations of rural area of Japan, had high prevalence of both H. pylori infection and serological atrophy of gastric mucosa. These facts should be considered in discussing results of the nested case-control study.

Adult↗

PubMed2005

Medical history of circulatory diseases and colorectal cancer death in the JACC Study.

BACKGROUND: Host factors expressed by individual past medical history of hypertension, stroke, and myocardial infarction may have a relationship with colorectal cancer. METHODS: As part of the Japan Collaborative Cohort Study (JACC Study) for the Evaluation of Cancer Risk sponsored by the Ministry of Education, Science, Sports and Culture of Japan (Monbusho), we conducted a follow-up study of 110,792 Japanese inhabitants aged 40-79 years to reveal the relationship of past medical history of hypertension, stroke, and myocardial infarction at the baseline in 1988-1990 with colorectal cancer death for about 10 years up to the end of 1999. RESULTS: Past medical history of hypertension associated with an increased risk of female rectal cancer when analyzing all cancer cases with adjustment for age, body mass index, and exercise (hazard ratio [HR]=1.97, 95% confidence interval [CI]; 1.13-3.43). Past medical history of myocardial infarction was also an increased risk for female rectal cancer (HR=3.05, 95% CI; 1.28-7.28). Females who had a medical history of stroke had increased risk of rectal cancer without statistical significance. CONCLUSION: There was a positive association of past medical history of hypertension and myocardial infarction and an increased risk of rectal cancer in women.

Adult↗

PubMed2005

Alcohol consumption and colorectal cancer risk: findings from the JACC Study.

BACKGROUND: Because alcohol drinking is a potential risk factor for colorectal cancer, the trend in alcohol consumption in Japan may partly explain the increase in incidence and mortality rates of this malignancy until 1990-1995. METHODS: We analyzed data from the Japan Collaborative Cohort Study. From 1988 to 1990, 23,708 men and 34,028 women, aged 40-79 years, completed a questionnaire on lifestyle factors including drinking habits. Incidence rate ratios (IRR) were estimated by using proportional hazards models. RESULTS: During the mean follow-up of 7.6 years through December 1997, we documented 418 incidents of colon cancer and 211 of rectal cancer. Male ex- or current drinkers demonstrated a twofold risk for colon cancer compared with nondrinkers: the multivariate-adjusted IRR was 2.01 (95% confidence interval [CI] 1.09-3.68) for ex-drinkers and 1.97 (95% CI: 1.28-3.03) for current drinkers. The doseresponse relationship between alcohol consumption and the risk, however, was not clear. Female exdrinkers were at an increased risk without statistical significance. For rectal cancer, we found a slightly lower risk in light current drinkers who consumed less than 22 g ethanol per day: the multivariate IRR was 0.61 (95% CI: 0.33-1.13) for men and 0.69 (95% CI: 0.27-1.74) for women. Although the IRR for all current drinkers was almost unity in men, an increasing trend in risk was detected with increasing alcohol consumption in current drinkers (trend p=0.027). CONCLUSIONS: Taking the findings from our study and other prospective investigations into consideration, more attention should be paid to alcohol consumption in the prevention of colon cancer in Japan.

Adult↗

PubMed2005

Glucose intolerance and colorectal cancer risk in a nested case-control study among Japanese People.

BACKGROUND: Glucose intolerance may increase the risk of developing colorectal cancer. METHODS: In a sero-epidemiological nested case-control study, conducted as part of the Japan Collaborative Cohort Study (JACC Study) for Evaluation of Cancer Risk, we measured serum glycoalbumin in 123 patients with colorectal cancer and 279 controls. Conditional logistic regression was used to evaluate the risk of colorectal cancer. RESULTS: There were trends towards an association between high levels of glycoalbumin and an increased risk of colorectal cancer in men (odds ratio [OR]=2.39; 95% confidence interval [CI]; 0.89- 6.36) and between high levels of glycoalbumin and a decreased risk of colorectal cancer in women (OR=0.41; 95% CI, 0.14-1.04). CONCLUSIONS: A high level of glycoalbumin may increase the risk of colorectal cancer in men. The finding that high levels of glycoalbumin in women decreased their risk of colorectal cancer was inconsistent with previous reports, and may have been the result of limitations in the procedure in selecting samples and statistical power.

Adult↗

PubMed2005

Colorectal cancer and serum C-reactive protein levels: a case-control study nested in the JACC Study.

BACKGROUND: Recently, it has been hypothesized that inflammation increases the risk of colorectal cancer. We investigated whether serum levels of C-reactive protein (CRP), a biomarker of inflammation, are associated with colorectal cancer, using serum samples collected in the Japan Collaborative Cohort Study (JACC Study). METHODS: We conducted a nested case-control study in the JACC Study, investigating the relationship between the risk for colorectal cancer and serum levels of CRP determined by a high-sensitivity CRP enzyme immunoassay. The subjects recruited were 141 patients with colorectal cancer (63 males and 78 females) and 327 controls with no history of cancer (148 males and 179 females). Each case of colorectal cancer was matched for sex, age and participating institution to 2 or 3 controls. We used ttest to analyze mean differences in CRP levels between colorectal cancer cases and controls. Odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated using a conditional logistic regression model after adjusting for the potential confounding factors. RESULTS: Serum CRP levels were not clearly associated with the risk of colorectal cancer. The OR of the highest serum CRP levels was 1.18 (95% CI: 0.68-2.06) for colorectal cancer and 1.42 (95% CI: 0.73-2.74) for colon cancer, compared to subjects with lowest serum levels. The OR for incidence of colorectal cancer showed a similar trend, but the difference was not significant. Thus, high serum CRP levels did not appear to increase the risk of colorectal cancer. CONCLUSIONS: The present results suggest that high serum CRP levels are not associated with the risk of colorectal cancer in the JACC Study.

Adult↗

PubMed2005

Dietary habits and stomach cancer risk in the JACC Study.

BACKGROUND: Despite a declining incidence, stomach cancer is still a dominant cancer in Japan. The association between dietary habits and stomach cancer risk was investigated in a large prospective study in Japan. METHODS: Data were obtained using a self-administered questionnaire from 1988 through 1990. Food frequency questionnaire was used to evaluate the consumption of 33 selected food items. Proportional hazard model was used to determine the hazard ratios (HRs) and their 95% confidence intervals (CIs) of stomach cancer for different levels of the dietary intakes. RESULTS: A western style breakfast showed an inverse association with stomach cancer risk in males (HR=0.49, 95% CI: 0.35-0.70). Women who consumed liver three to four times per week and more than once per day had a significant increased risk, respectively (HR=2.02, 95% CI: 1.12-3.63, HR=3.16, 95% CI: 1.16-8.62 ). A clear dose-response relationship between the intake of liver and stomach cancer risk was observed. We found no association between stomach cancer mortality and the consumption of fruit such as mandarin orange, and vegetables such as carrots and spinach in both men and women. The consumption of high salt foods such as miso soup and pickles was also not significantly associated with the mortality of stomach cancer in both sexes. CONCLUSION: This prospective study suggested that a western-style breakfast is associated with a lower risk of stomach cancer, although some differences in the association were seen between men and women.

Adult↗

PubMed2004

Initial experience with catheter probe US when using a multibending endoscope.

BACKGROUND: High-frequency catheter probe US provides detailed images when the scanning plane is perpendicular to the area of interest and the latter is within the focal zone. A multibending endoscope has been developed that has two bending sections that can be deflected independently. The aim of this study was to determine whether this new endoscope enhances high-frequency catheter probe US. METHODS: High-frequency catheter probe US was performed with the multibending endoscope in 33 patients with upper-GI lesions. The endoscope was carefully maneuvered until the scanning plane was perpendicular to the area of interest and the target area was within the focal zone of the probe. The effects of deflecting the second bending section on the image and on the rotating elements in the probe were evaluated. RESULTS: For 28 lesions, no improvement was observed with use of both bending sections. However, for 5 lesions, the US image was improved by use of the second bending section. These lesions were located in the stomach on the lesser or greater curve. In no instance did deflection of both bending sections result in uneven rotation of the mechanical elements in the probe. CONCLUSIONS: For certain lesions, US images obtained with a catheter probe can be improved by using an endoscope with a second bending section.

Catheterization↗

PubMed2004

A prospective study on the possible association between having children and colon cancer risk: findings from the JACC Study.

If having children is regarded as an exposure in life, its effect on a host could be considered as being due to female sex hormones associated with pregnancy in women and some lifestyle factors associated with large families in both men and women. To explore the roles of having children in the etiology of colon cancer, we examined 36,629 women and 24,877 men aged 40-79 years who completed a questionnaire on the number of children and other lifestyle factors from 1988 to 1990 in the Japan Collaborative Cohort Study for Evaluation of Cancer Risk. During 291,080 and 200,648 person-years of follow-up, we documented 198 female and 202 male incident colon cancers, respectively. After adjusting for some factors known or suspected to modify the risk of colon cancer, compared with the women with no children, the multivariate-adjusted relative risks of colon cancer were 0.74 (95% confidence interval [CI]: 0.30-1.84) for one child, 1.00 (95% CI: 0.46-2.20) for two, 0.70 (95% CI: 0.31-1.55) for three, and 0.59 (95% CI: 0.26-1.33) for four or more. The risk of colon cancer showed a significantly monotonic decrease with increasing number of children (P value for trend = 0.047). There was no association between the number of children and colon cancer risk among men. From these prospective data, having children may reduce risk of colon cancer among women, but not among men, suggesting that modifications of hormone profiles secondary to pregnancies may influence female colon cancer risk.

Adult↗

PubMed2004

A prospective study of reproductive and menstrual factors and colon cancer risk in Japanese women: findings from the JACC study.

The effects of reproductive factors on the etiology of colon cancer in Asian populations remain unexplored. So we examined 38,420 Japanese women aged 40-79 years who responded to a questionnaire on reproductive and other lifestyle factors from 1988 to 1990 in the Japan Collaborative Cohort Study for Evaluation of Cancer Risk. During an average 7.6 years of follow-up, we documented 207 incident colon cancers. Multivariate analysis indicated that colon cancer risk was likely to be lower among parous women than among nulliparous. Women who had two abortions or more had a 72% higher risk of developing colon cancer [relative risk (RR) 1.72; 95% confidence interval (CI) 1.16-2.55; trend P < 0.01] compared with women who never had an abortion. The RR of colon cancer among postmenopausal women significantly decreased with increasing age at menarche (trend P = 0.01). No apparent association between colon cancer and gravida, age at first birth, age at menopause, or duration of menstruation was seen. These prospective data support the hypothesis that female reproductive events modify colon cancer risk, and suggest that reproductive factors, particularly age at menarche and having an abortion, may be of importance in the etiology of colon cancer among Japanese women.

Abortion, Induced↗

PubMed2004

Diet and colorectal cancer mortality: results from the Japan Collaborative Cohort Study.

The relationship between diet and colorectal cancer mortality was analyzed in a prospective study of 45,181 men and 62,643 women aged 40-79 yr enrolled in the Japan Collaborative Cohort Study. Between 1988 and 1990, subjects completed a self-administered questionnaire on their sociodemographic characteristics, diet, and other lifestyle habits. During the follow-up period (average 9.9 yr), 284 colon cancer deaths (138 men and 146 women) and 173 rectal cancer deaths (116 men and 57 women) were confirmed. The only significant association of colorectal cancer mortality with vegetable intake was observed between male rectal cancer mortality and green leafy vegetable consumption [hazard ratio (HR) using Cox proportional hazard models = 0.6; 95% confidence interval (CI) = 0.3-0.9; P for trend = 0.02]. Yogurt intake was also inversely associated with male rectal cancer mortality (HR = 0.5; 95% CI = 0.2-1.0; P for trend = 0.04). Egg consumption was positively associated with male colon cancer mortality (P for trend = 0.04). Women with high fruit consumption had increased colon cancer mortality (HR = 1.6; 95% CI = 1.0-2.6; P for trend = 0.04). It should be noted that this study lacked statistical power due to small sample size and measurement error in the food-frequency questionnaire. Further investigation is therefore necessary to confirm the association between diet and colorectal cancer, especially by subsites and gender.

Adult↗

PubMed2004

Serum oxidized low-density lipoprotein levels and risk of colorectal cancer: a case-control study nested in the Japan Collaborative Cohort Study.

Oxidative stress plays an important role in carcinogenesis, but few epidemiologic studies have examined associations with risk of colorectal cancer. Relationships between serum levels of oxidized low-density lipoprotein (oxLDL) and oxLDL antibody (oLAB) and colorectal cancer risk were investigated in a case-control study nested in the Japan Collaborative Cohort Study for Evaluation of Cancer Risk. Serum samples and lifestyle information were collected at baseline from 39,242 men and women between 1988 and 1990. Of these, 161 incidents and deaths from colorectal cancer were identified through 1999, and 395 controls were matched for gender, age, and study area. Measurements were taken of serum oxLDL levels in 119 cases and 316 controls and serum oLAB levels in 153 cases and 376 controls. Odds ratios (95% confidence intervals) across quartiles, adjusted for confounding factors, were 1.55 (0.70-3.46), 1.90 (0.84-4.28), and 3.65 (1.50-8.92) for oxLDL (P(trend) = 0.004) and 0.98 (0.54-1.80), 0.75 (0.39-1.48), and 1.68 (0.90-3.13) for oLAB (P(trend) = 0.140). Further adjustment for serum total cholesterol and alpha-tocopherol did not materially change these associations. Odds ratio (95% confidence interval) of the highest quartile of serum oxLDL compared with the lowest quartile was 3.40 (1.09-10.58; P(trend) = 0.045). Analyses restricted to colon cancer cases and corresponding controls yielded similar relationships between serum oxLDL and oLAB levels and risk. In conclusion, higher levels of serum oxLDL may increase risk of colorectal cancer.

Adult↗

PubMed2003

Prospective study of screening for stomach cancer in Japan.

Although screening for stomach cancer is a widespread community service in Japan, the benefits of the screening program remain unclear. Our study investigated prospectively the relation between participation in stomach-cancer screening during the past 12 months and subsequent deaths. Data was derived from the Japan Collaborative Cohort Study, in which 480 stomach-cancer deaths were identified during an 8-year follow-up period. Cox proportional hazard regression was used to estimate the relative risk of death from stomach cancer and that from other causes while adjusting for potential confounding factors. In men, screening participation was associated significantly with a reduced risk of death from stomach cancer (relative risk [RR] = 0.54; 95% confidence interval [CI] = 0.41-0.70). The extent of the risk reduction was greater than potential health selection (for deaths other than stomach, RR = 0.71). The adjustment for potential confounding variables, however, attenuated the difference in risk of death (stomach cancer, RR = 0.65; other causes, RR = 0.71). In women, the magnitude of the association between screening participation and death from stomach cancer (RR = 0.74; 95% CI = 0.52-1.07) was equal to that for deaths from non-stomach cancers (RR = 0.74). Subgroup analysis showed that women with a parental history of stomach cancer had a reduced risk of death from stomach cancer associated with screening (RR = 0.32; 95% CI = 0.12-0.87). The present results underline the potential for selection bias in observational studies, and thus it remains an open question whether screening for stomach cancer is effective.

Adult↗