Yayoi Koizumi

Obesity and risk of cancer in Japan

We conducted a population‐based prospective cohort study in Japan to examine the relationship between body mass index (BMI) and the risk of incidence of any cancer and of cancer at individual sites. Body mass index was calculated from self‐administered body weight and height at baseline. Relative risks (RR) and 95% confidence intervals (CI) were calculated in multivariate proportional‐hazards models. Among 27,539 persons (15,054 women and 12,485 men) aged 40 years or older who were free of cancer at enrollment in 1984, 1,672 (668 women and 1,004 men) developed cancer during 9 years of follow‐up. In women, after adjustment for potential confounders, the RR of all cancers associated with different BMI, relative to a BMI of 18.5–24.9, were 1.04 (95% CI = 0.85–1.27) for BMI = 25.0–27.4, 1.29 (1.00–1.68) for BMI = 27.5–29.9 and 1.47 (1.06–2.05) for BMI ≥30.0 (p for trend = 0.007). Higher BMI was also significantly associated with higher risk of cancers of the colorectum, breast (postmenopausal), endometrium and gallbladder in women. In men, we observed significantly increased all‐cancer risk among only never‐smokers. Overweight and obesity could account for 4.5% (all subjects) or 6.2% (never‐smokers) of the risk of any cancer in women and −0.2% (all subjects) or 3.7% (never‐smokers) in men. The value for women was within the range among women reported from Western populations (3.2%–8.8%). Our data demonstrate that excess weight is a major cancer risk among Japanese women.

Coffee consumption and the risk of primary liver cancer: Pooled analysis of two prospective studies in Japan

Although case‐control studies suggested that coffee consumption is associated with a decreased risk of liver cancer, no prospective cohort study has been carried out. To examine the association between coffee consumption and the risk of liver cancer, we conducted a pooled analysis of data available from 2 cohort studies in Japan. A self‐administered questionnaire about the frequency of coffee consumption and other health habits was distributed to 22,404 subjects (10,588 men and 11,816 women) in Cohort 1 and 38,703 subjects (18,869 men and 19,834 women) in Cohort 2, aged 40 years or more, with no previous history of cancer. We identified 70 and 47 cases of liver cancer among the subjects in Cohort 1 (9 years of follow‐up with 170,640 person‐years) and Cohort 2 (7 years of follow‐up with 284,948 person‐years), respectively. We used Cox proportional hazards regression analysis to estimate the relative risk (RR) and 95% confidence interval (CI) of liver cancer incidence. After adjustment for potential confounders, the pooled RR (95% CI) of drinking coffee never, occasionally and 1 or more cups/day were 1.00 (Reference), 0.71 (0.46–1.09) and 0.58 (0.36–0.96), respectively (p for trend = 0.024). In the subgroup of subjects with a history of liver disease, we found a significant inverse association between coffee consumption and the risk of liver cancer. Our findings support the hypothesis that coffee consumption decreases the risk of liver cancer. Further studies to investigate the role of coffee in prevention of liver cancer among the high‐risk population are needed.

Factors associated with suicidal ideation in an elderly urban Japanese population: A community‐based, cross‐sectional study

Abstract  The objective of the present study was to evaluate the association between suicidal ideation and potentially related factors in an elderly urban Japanese population. This was a community‐based, cross‐sectional study. Urban community residents aged 70 years or more were interviewed regarding suicidal ideation and sociodemographic and health‐related variables. Subjects with depressive symptoms underwent further evaluation by psychiatrists using criteria of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition. Associations were evaluated using univariate and multivariate logistic regression analyses. Of the 1145 eligible participants, 52 (4.5%) reported thoughts of suicide. Of 143 subjects with depressive symptoms (Geriatric Depression Scale, 14+), 22 (15.4%) reported suicidal ideation over a 2‐week period. After controlling for depressive symptoms, lack of social support and impaired instrumental activities of daily living were significantly associated with thoughts of suicide. After controlling for the potentially associated factors detected in the univariate analysis, depressive symptoms were strongly associated with thoughts of suicide. In the elderly with depressive symptoms, mental disorders, including depressive and alcohol‐related disorders, were significantly associated with suicidal ideation over a 2‐week period. In the urban community setting, screening for lack of social support, impaired instrumental activities of daily living, and depressive symptoms, followed by diagnostic evaluation for mental disorders, particularly for depressive syndromes and alcohol‐related disorders, may provide a practical and effective means of identifying elders at high risk of suicide.

Cigarette smoking and the risk of gastric cancer: a pooled analysis of two prospective studies in Japan.

To examine the association between cigarette smoking and the risk of gastric cancer, we conducted a pooled analysis of 2 population‐based prospective cohort studies in rural northern Japan. Cohort 1 included 9,980 men (≥40 years old) and Cohort 2 included 19,412 men (40–64 years old). The subjects completed a self‐administered questionnaire on cigarette smoking and other health habits. We identified 228 cases of gastric cancer among Cohort 1 subjects (9 years of follow‐up with 74,073 person‐years) and 223 among Cohort 2 subjects (7 years of follow‐up with 141,675 person‐years). From each cohort, we computed the relative risk (RR) and 95% confidence interval (CI) of gastric cancer associated with smoking using a Cox regression analysis and pooled these estimates to obtain summary measures. The pooled multivariate RRs (95% CIs) for current smokers and past smokers compared to subjects who had never smoked were 1.84 (1.39–2.43) and 1.77 (1.29–2.43), respectively. The higher number of cigarettes smoked per day among current smokers was associated with a linear increase in risk (trend p < 0.05). The significant increase in risk for past smokers remained for up to 14 years after cessation. An increased risk was noted for cancer of the antrum but not for cardia or body lesions. The risk was increased for both differentiated and nondifferentiated histologic subtypes. Our findings support the hypothesis that cigarette smoking is a risk factor for gastric cancer.

Association between social support and depression status in the elderly: Results of a 1‐year community‐based prospective cohort study in Japan

Abstract  We conducted a prospective cohort study on subjects aged ≥ 70 years in an urban community to determine whether there is any association between lack of social support and depression status. Of the 2730 eligible subjects, 1178 participated and were interviewed in a Comprehensive Geriatric Assessment (CGA) in 2002. We investigated the five social supports items using the following questions: (i) do you have someone with whom you can consult when you are in trouble?, (ii) do you have someone with whom you can consult when your physical condition is not good?, (iii) do you have someone who can help you with your daily housework?, (iv) do you have someone who can take you to a hospital when you do not feel well?, and (v) do you have someone who can take care of you when you are ill in bed? The Geriatric Depression Scale was used to estimate depression status. The subjects were divided into two groups: depressive and non‐depressive. Of 753 subjects classified as non‐depressive, 475 also took part in a CGA in 2003 and 278 dropped out. We calculated the risk of depression status in the elderly without social support. Lack of social support items (i) and (v) were significantly associated with an increased risk of depression status. The multivariate odds ratios (95% confidence intervals) regarding the risk of depression status among the elderly without (i) and (v) social support items were 2.6 (1.2–5.3) and 3.0 (1.4–6.1), respectively. We also found the increase risk of depression status with lack of social support item (v) was significantly different for different sexes and for different pain conditions. We conclude that there is a significant increase in the risk of depression status associated with the lack of social support in Japanese elderly people in an urban community.

Involvement of plasma membrane H+‐ATPase in anoxic elongation of stems in pondweed (Potamogeton distinctus) turions

• Pondweed (Potamogeton distinctus) turions can elongate in the absence of O(2). Alcoholic fermentation serves to produce energy for anoxic elongation via the breakdown of starch stored in cells. However, the mechanism of cell growth during anoxic elongation is not fully understood. • Changes in pH, H(+) equivalent and lactate content of the incubation medium were measured during anoxic elongation. The effects of fusicoccin (FC), indole-3-acetic acid (IAA), vanadate, erythrosine B and K(+) channel blockers on anoxic elongation were examined. Cytoplasmic pH and vacuolar pH were measured by (31)P nuclear magnetic resonance (NMR) spectroscopy. • Acidification of the incubation medium occurred during anoxic elongation. The contribution of CO(2) and lactic acid was not sufficient to explain the acidification. FC and IAA enhanced the elongation of stem segments. Vanadate and erythrosine B inhibited anoxic elongation. Acid growth of notched segments was observed. The activity of plasma membrane H(+)-ATPase extracted from pondweed turions was increased slightly in anoxic conditions, but that from pea epicotyls sensitive to anoxic conditions was decreased by incubation in anoxic conditions. Both the cytoplasmic pH and vacuolar pH of pondweed turion cells chased by (32)P NMR spectroscopy were stabilized during a short period < 3 h after anoxic conditions. • We propose that the enhancement of H(+) extrusion by anoxic conditions induces acidification in the apoplast and may contribute to the stabilization of pH in the cytoplasm.

Phylogenetic position of Oxygyne shinzatoi (Burmanniaceae) inferred from 18S rDNA sequences.

The genus Oxygyne comprises three species disjunctly distributed in Africa and Japan and is the least examined genus of the Burmanniaceae due to the scarcity of living material. We obtained living samples of Oxygyne shinzatoi and examined the phylogenetic position of this species on the basis on the 18S rDNA sequence. Oxygne shinzatoi was consistently found to belong to the monophyletic group of tribe Thismieae, but its position in the tribe differed depending on the criteria applied (maximum parsimony, maximum likelihood, Bayesian inference). Distance analysis from the most recent common ancestor indicated that O. shinzatoi had the lowest substitution rate among the species of tribe Thismieae. Combined with recent knowledge of basic chromosome numbers and substitution rate characteristics, O. shinzatoi can be considered to be one of the basal taxon of tribe Thismieae.

Phylogenetic position of Oxygyne shinzatoi

In an article published in the Journal of Plant Research (121:27–32), we reported that we had conducted molecular phylogenetic analyses of Burmanniaceae to reveal the phylogenetic position of Oxygyne shinzatoi, a living sample obtained from the second collection series of the species since its discovery. In that article, we neglected to cite the accession number of the 18SrDNA sequence of Oxygyne shinzatoi. The sequence was released in the DDBJ/EMBL/GenBank international DNA databases under the accession number AB437090. This information was the first report of the molecular sequence of the genus. The authors cordially express their sincere gratitude to Dr. V. Merckx for pointing out the error.