Nao Seki

Daytime napping and mortality, with a special reference to cardiovascular disease: the JACC study

BACKGROUND Daytime napping is associated with elevated risk of all-cause mortality in the elderly. However, the association with cardiovascular disease (CVD) risk is inconsistent. METHODS From 1988 to 1990, a total of 67 129 Japanese non-workers or daytime workers (27 755 men and 39 374 women) aged 40-79 years, without a history of stroke, heart disease or cancer, completed a lifestyle questionnaire. They were followed for mortality until the end of 2003. RESULTS During the 879 244 person-year follow-up, 9643 deaths (2852 from CVD, 3643 from cancer, 2392 from other internal causes, 738 from external causes and 18 from unspecified causes) were observed. After adjustment for possible confounders, subjects with a daytime napping habit had elevated hazard ratios (HRs) for mortality from all causes [HR 1.19, 95% confidence interval (CI) 1.14-1.24, P < 0.001], CVD (HR 1.31, 95% CI 1.22-1.42, P < 0.001), non-cardiovascular/non-cancer internal diseases (HR 1.26, 95% CI 1.16-1.37, P < 0.001) and external causes (HR 1.28, 95% CI 1.10-1.50, P = 0.001), but not for cancer death (HR 1.03, 95% CI 0.96-1.10, P = 0.400). The risk of CVD mortality associated with daytime napping was diminished among overweight subjects, but pronounced in those with weight loss after age 20 years, with non-regular employment, with lower education level and with a follow-up period <5 years. CONCLUSIONS Daytime napping is associated with elevated risk of CVD mortality as well as non-cardiovascular/non-cancer and external deaths. Daytime napping may elevate risk of CVD death through some biological effects but, to a larger extent, some comorbid disorders causing weight loss or associated with non-regular employment and low education level could explain this association.

Dietary Habits and Risk of Lung Cancer Death in a Large-scale Cohort Study (JACC Study) in Japan by Sex and Smoking Habit

Lung cancer has increased and is the leading cause of cancer death among Japanese males. The associations of dietary habits with the risk of lung cancer death were evaluated by sex and smoking habits in this study. In the Japan Collaborative Cohort (JACC) Study, a cohort established in 1988–90 and consisting of 42 940 males and 55 308 females was observed for lung cancer deaths up to the end of 1997. During the observation period, 446 males and 126 females died of lung cancer. A self‐administered food frequency questionnaire was used as the baseline survey. Hazard ratios for dietary factors were calculated by Coxs proportional hazards model. Among males, a high intake of ham and sausages, cheese, green‐leafy vegetables, oranges, and other fruits significantly and dose‐dependently decreased the risk of lung cancer death. Among females, a high intake of miso‐soup, ham and sausages, and liver significantly and almost dose‐dependently increased the risk. Vegetables and fruits rich in antioxidative and carcinogenic agents reduced the risk of lung cancer deaths among male smokers more than among female nonsmokers. The results among female nonsmokers were partially consistent with the hypothesis that high fat consumption increases the risk of lung cancer, especially that of adenocarcinoma.

Attributable and absolute risk of lung cancer death by smoking status: findings from the Japan Collaborative Cohort Study.

Estimating the proportion of lung cancer deaths that can be avoided is important in assessing the potential impact of antismoking efforts on the reduction of lung cancer deaths. We calculated the population attributable risk (PAR) and absolute risk of lung cancer death according to smoking status based on the Japan Collaborative Cohort (JACC) Study. The analytic cohort included 45,010 males and 55,724 females aged 40–79 years. Cox proportional hazards model was used to determine age‐adjusted relative risks and PAR according to smoking status. We also computed lung cancer mortality according to age and smoking status. In males, 52.2% and 14.8% of lung cancer deaths were attributable to current and former cigarette smoking, respectively. In females, the corresponding figures were 11.8% and 2.8%. Among current male smokers, the relative risk was strongly correlated with the intensity and duration of cigarette smoking. In contrast, the PAR was associated with an intermediate level of smoking except for the years of smoking: the largest PARs were observed in those with 20–29 cigarettes per day, 40–59 pack‐years and 20–22 years old at starting smoking. Absolute risks were estimated to increase with age and duration of smoking and not to decrease even after cessation. These findings suggest that avoidable lung cancer deaths are primarily among light to moderate smokers who are considered amenable to population‐based antismoking strategies. For all current smokers, immediate cessation is encouraged because it offers the only realistic way to avoid a substantial increase in lung cancer mortality brought about by further continuation of smoking.

Serum carotenoids and mortality from lung cancer: a case-control study nested in the Japan Collaborative Cohort (JACC) Study

To investigate whether high serum levels of carotenoids, tocopherols, and folic acid decrease risk of lung cancer in Japanese, we conducted a case‐control study nested in the Japan Collaborative Cohort (JACC) Study. A total of 39 140 subjects provided serum samples at baseline between 1988 and 1990. We identified 147 cases (113 males and 34 females) of death from lung cancer during an 8‐year follow‐up. Of the subjects who survived to the end of this follow‐up, 311 controls (237 males and 74 females) were selected, matched to each case of lung cancer death for gender, age and participating institution. We measured serum levels of antioxidants in cases of lung cancer death and controls. Odds ratios (ORs) for lung cancer death were estimated using conditional logistic models. The risk of lung cancer death for the highest quartile of serum α‐carotene, β‐carotene, lycopene, β‐cryptoxanthin, and canthaxanthin was significantly or marginally significantly lower than for the lowest quartile: the ORs, adjusted for smoking and other covariates, were 0.35 (95% confidence interval (Cl), 0.14–0.88), 0.21 (0.08–0.58), 0.46 (0.21–1.04), 0.44 (0.17–1.16) and 0.37 (0.15–0.91), respectively. The ORs for the highest serum levels of zeaxanthin/lutein and folic acid tended to be low, but the differences were not statistically significant. Serum total cholesterol was also inversely related to risk of lung cancer death: the OR for the highest vs. the lowest quartile was 0.39 (95% Cl, 0.19–0.79). Higher serum levels of carotenoids such as α‐ and β‐carotenes may play a role in preventing death from lung cancer among Japanese. (Cancer Sci 2003; 94: 57–63)

Influenza vaccination levels and influenza-like illness in long-term-care facilities for elderly people in Niigata, Japan, during an influenza A (H3N2) epidemic.

Surveys on influenza vaccination and illness in long-term-care facilities in Niigata Prefecture during an influenza A (H3N2) epidemic revealed that >20% of facilities had outbreaks and >10% of residents experienced influenza. Outbreaks and number of cases were significantly reduced by vaccination, which should be strongly recommended for institutionalized elderly people.

Serum Insulin‐like Growth Factors, Insulin‐like Growth Factor‐binding Protein‐3, and Risk of Lung Cancer Death: A Case‐control Study Nested in the Japan Collaborative Cohort (JACC) Study

To elucidate the roles of insulin‐like growth factors (IGFs) in the development of lung cancer, we conducted a case‐control study nested within the Japan Collaborative Cohort Study. Serum samples were collected at baseline from 39 140 men and women between 1988 and 1990. We measured serum IGF‐I, IGF‐II, and IGF‐binding protein‐3 (IGFBP‐3) in 194 case subjects who subsequently died from lung cancer during an 8‐year follow‐up and in 9351 controls. The odds ratios (ORs), adjusted for smoking and other covariates, were smaller with higher levels of IGF‐II and IGFBP‐3. The ORs across quartiles were 0.41 (95% confidence interval [CI], 0.27–0.63), 0.47 (0.31–0.71), and 0.67 (0.46–0.98) for IGF‐II (trend P=0.018), and 0.55 (95% CI, 0.37–0.81), 0.54 (0.36–0.82), and 0.67 (0.45–1.01) for IGFBP‐3 (trend P=0.037). These peptides were not independently related to lung cancer risk when mutually adjusted. The risk was increased in the highest vs. the lowest quartile of IGF‐I only after controlling for IGFBP‐3 (OR, 1.74; 95% CI, 1.08–2.81). Limiting subjects to those followed for ≥3 years strengthened the negative associations of IGF‐II and IGFBP‐3, whereas the ORs for IGF‐I generally decreased. A higher level of circulating IGFBP‐3 and/or IGF‐II may decrease lung cancer risk. Elevated serum IGF‐I may increase the risk, but this could partly be attributable to latent tumors.

Consumption of green and roasted teas and the risk of stroke incidence: results from the Tokamachi–Nakasato cohort study in Japan

BACKGROUND and purpose Green tea consumption is inversely associated with death from stroke. The purpose of the present study was to assess whether it is inversely associated with subsequent stroke incidence and whether this association is preserved even with roasted tea leaves. METHODS In 1998, 6358 Japanese adults (2087 men and 4271 women) aged 40-89 years without a history of stroke or heart disease completed a lifestyle questionnaire, including consumption of green tea or roasted tea. By the end of 2003, 110 stroke events (59 cerebral infarction events, 34 cerebral haemorrhage events, 15 subarachnoidal haemorrhage events and two stroke events of unspecified subtype) had been documented. Cox proportional hazards regression analysis was used to calculate the multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) for total stroke events, cerebral infarction events and cerebral haemorrhage events according to consumption categories of green tea and roasted tea. RESULTS A considerably lower risk was observed for total stroke incidence in both the middle (multivariable HR, 0.43; 95% CI, 0.25-0.74; P = 0.002) and the high (multivariable HR, 0.41; 95% CI, 0.24-0.70; P = 0.001) categories of green tea consumption. This inverse association was consistent even when cerebral infarction and cerebral haemorrhage were analysed separately. The consumption of roasted tea was not associated with stroke risk. CONCLUSIONS Green tea consumption is associated with a reduced risk of total stroke incidence, cerebral infarction and cerebral haemorrhage.

Cigarette smoking and glutathione S‐transferase M1 polymorphism associated with risk for uterine cervical cancer

Aim:  To elucidate the role of tobacco smoking and polymorphisms of carcinogen metabolism genes in cervical carcinogenesis.

The effectiveness of influenza vaccine against influenza a (H3N2) virus infections in nursing homes in Niigata, Japan, during the 1998-1999 and 1999-2000 seasons.

OBJECTIVE To evaluate the effectiveness of influenza vaccines against influenza-like illness (ILI) among nursing home residents. DESIGN Prospective, nonrandomized, cohort study. SETTING Nine nursing homes during the 1998-1999 influenza season and 11 nursing homes during the 1999-2000 influenza season in Niigata Prefecture, Japan. PARTICIPANTS Six hundred ninety-nine residents and 440 healthcare workers (HCWs) during the first season, and 930 residents and 517 HCWs during the second season, with vaccination rates ranging from 0% to 97.7%. RESULTS Overall, ILI decreased from 24.3% during the 1998-1999 season to 8.8% during the 1999-2000 season. Multivariate analysis adjusted for several factors, including gender, age, underlying diseases, and resident and HCW vaccination rates, failed to demonstrate clear individual protection of residents (relative risk [RR], 1.42; P = .2 for the first season; RR, 0.95; P = .9 for the second season). However, vaccination rates of 60% or greater for residents and HCWs reduced the risk of ILI, and also could prevent outbreaks during the 2 seasons. Highly impaired activities of daily living and chronic respiratory diseases were significantly associated with increased ILI. CONCLUSIONS A high vaccination rate for both residents and HCWs may reduce the risk of ILI and institutional outbreaks in nursing homes.

Evidence-based tool for triggering school closures during influenza outbreaks, Japan.

In this letter, we report the first infrared spectrum of C(76)(2-). This multiply charged anion has been studied in an electrodynamic ion trap held at room temperature using tunable infrared radiation from a free-electron laser. Resonant vibrational excitation is found to cause electron detachment and the resulting singly negatively charged as well as the remaining doubly charged parent ion are monitored as a function of IR wavelength in an experimental scheme that we term infrared multiphoton electron detachment spectroscopy. The obtained IR spectra are contrasted to computed vibrational spectra using density functional theory. The dianionic molecule retains its overall symmetry (i.e., D(2) point group) with a (1)A(1) ground state with respect to the neutral fullerene. Spectral shifts of characteristic tangential modes relative to the neutral cage are shown to originate from the excess charge density.