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Liquid crystal tunable filter (LCTF) can change the transmissible wavelength by changing the applied voltage to the filter, which enables the drastic increase in the observable wavelength resolution in a small size system and is considered to be a powerful tool for the spectral earth observation from flying units or microsatellites. However, there is limited knowledge about its season-long application for the vegetation monitoring and the prediction of the ecosystem photosynthetic capacity. We compared the seasonal variation of spectral reflectance obtained by a LCTF camera with that obtained by a popular spectral radiometer in a cool-temperate young larch plantation in northern Hokkaido, Japan. Then we tried to find the best normalized difference spectral index (NDSI) to explain the seasonal variation of the ecosystem photosynthetic capacity using all pairs of two reflectances observed in the range of wavelength between 500 and 770 nm with 10-nm intervals (28 wavelength bands) by the LCTF. The best NDSI among all combinations (28x27) of two reflectances was NDSI[770, 720] for the maximum gross primary production at light saturation and NDSI[530, 600] for the initial slope of the light-response curve, which reflect the red edge shift owing to the change in the chlorophyll content and relative strength of the light absorbance in the visible red wavelength region compared with that in the green wavelength region, respectively. Predicted daily gross primary production of the plantation using these NDSI agreed well with the observed values. NDSI[530, 600] was better to distinguish each vegetation type of the studied plantation.

Thinning is a necessary procedure for the sustainable management of plantation forests. Thinning has a remarkable influence on forest carbon balance; however, there are limited studies showing the integrated assessment of the effects of thinning on several understory carbon flux components using long-term monitoring data. We measured understory flux components using automated chambers continuously over 12 years to understand the effects of forest thinning conducted in May 2014 and March 2015 and to elucidate the effect of short-term climate change on understory carbon balance in a Japanese larch (Larix kaempferi Sarg.) forest in central Japan. Although thinning (39% decrease in tree stems) increased the mean annual soil moisture by 16.5% and growing season soil temperature by 2.4%, large inter-annual variations in precipitation and soil temperature largely masked the effects of thinning on both soil respiration (Rs) and soil heterotrophic respiration (Rh). Annual mean soil temperature was positively related to all annual efflux components. Thinning also increased the understory photosynthetic photon flux density (PPFDu) by 63.1% during the growing season (May to October). In post-thinning years, the average three-year understory photosynthesis (GPPu), understory plant respiration (Rp), and total understory respiration (Ru) increased significantly by 59.5%, 99.7%, and 26.9%, respectively. The net understory CO2 exchange (NUE = Ru − GPPu) changed significantly only in 2015 (13.8%). A marginally significant change in NUE based on the three-year average in post-thinning years was also detected (14.4%). Our results indicated each flux component (especially GPPu, Rp, and Ru) changed dramatically after thinning. In contrast, the NUE of this forest was relatively more robust than other enhanced understory flux components. However, the marginally significant increase of NUE (3-year average in post-thinning years) implied a slight increase in NUE after thinning.

The Advanced Himawari Imager (AHI) onboard the recently launched next generation geostationary satellite, Himawari-8, provides an opportunity to improve Land Surface Phenology (LSP) detections over the Asia-Pacific region. In this paper, we detected four phenological transition dates (PTDs) using the three-day Two-band Enhanced Vegetation Index (EVI2) time series from AHI based on the Hybrid Piecewise Logistic Model-Land Surface Phenology Detection (HPLM-LSPD) algorithm. The four PTDs are Start of Spring (SOS), End of Spring (EOS), Start of Fall (SOF) and End of Fall (SOF). We evaluated the four AHI-derived PTDs against those detected using eight-day EVI2 time series from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the polar-orbiting satellite Terra, and three-day Green Chromatic Coordinate (GCC) time series from the Phenological Eyes Network (PEN) at six sites in central and northern Japan. The evaluation was performed by conducting regression analyses, and calculating root mean square difference (RMSD) and bias between satellite- and PEN-derived PTDs. First, the difference in the spatial variations of SOS and EOF timing between naturally vegetated areas, and urban areas and croplands indicates the anthropogenic footprints on LSP. Second, the RMSD of either AHI PTDs or MODIS PTDs against PEN PTDs were higher in the fall (i.e., SOF and EOF) than those in spring (i.e., SOS and EOS). Third, the later EOS and earlier SOF derived from satellite EVI2 relative to those derived from PEN GCC might be caused by the difference in the sensitivity of GCC and EVI2 to the increases in leaf area index (LAI) over high-LAI canopies. Fourth, the higher temporal resolution of AHI EVI2 only helped reduce the RMSD during spring compared to the RMSD for MODIS. In contrast, the RMSD for AHI PTDs and MODIS PTDs were comparable in fall. Finally, the between-sensor correlation in the spatiotemporal variability of the four PTDs was higher for SOS and EOF than those for EOS and SOF.

Upland soils are thought to be a sink of CH4, the second most important anthropogenic greenhouse gas, owing to oxidation by methanotrophs. To better understand CH4 fluxes in upland forests, we quasi-continuously measured CH4 fluxes using an automated closed chamber system over seven years on a larch plantation in a volcanic soil in Japan. We hypothesized that the long-term data sufficiently can calibrate modules for CH4 fluxes, and aimed to predict future pathways of CH4 uptake and their uncertainties in the forest. Based on the observations, a thinning of the overstory only marginally influenced the CH4 fluxes measured by the chambers. Using the data with a Bayesian method, we calibrated four modules for CH4 fluxes in forest soils, which were embedded in the process-based ecosystem model VISIT. The modules well reproduced the observed seasonality, annual budgets, and interannual variability in the CH4 fluxes after calibrating the following parameters: the diffusion coefficient or base CH4 oxidation rate constant and temperature sensitivity. The CH4 fluxes were predicted to increase in the future under the RCP8.5 scenario but to decrease under the RCP 2.6 scenario. The contrasting trajectory was caused by rising and decreasing CH4 concentrations under the RCP 8.5 and 2.6 scenarios, respectively. Furthermore, the magnitudes of the future changes in the fluxes differed in each module because the responses to the changes in the CH4 concentrations were inconsistent among the modules. The observed CH4 fluxes increased with increasing atmospheric CH4 concentration (4.95 mg CH4 m−2 d−1 ppm−1), which was greater in magnitude than those in the modules. Considering the uncertainties in the modules and potential confounding effects in the observations, we conclude that further understanding the responses of CH4 uptake to rising CH4 concentrations is required.

To validate terrestrial ecological products of the Global Change Observation Mission-Climate (GCOM-C) satellite, a large-scale ecological observation project "JAXA Super Sites 500" was initiated. The project’s purpose is to obtain the representative leaf area index (LAI), above-ground biomass (AGB), and fraction of absorbed PAR (fAPAR) in the satellite footprint scale. This study aimed to determine the appropriate observation methods in the satellite scale for the target land-cover types such as a deciduous broadleaved forest, evergreen/deciduous needle-leaved forests, and a grassland. As a result of the comparative observations, a combination method using litter-traps and LAI- 2200 was adopted as the LAI observation in a forest, a tree census method was adopted as the AGB observation in a forest, and a clipping method was adopted as the AGB and LAI observations in a grassland. LAI, AGB, and fAPAR were observed and were used to validate the GCOM-C terrestrial ecological products.

Plant canopy spectral reflectance is measured at many observation towers to estimate the canopy’s biophysical and physiological features. When a wide-angle downward-facing spectrometer is used for tower-based measurements of reflected irradiance, it also captures reflections from the tower and near-horizon light from the sky within the field of view, leading to incorrect canopy reflectance estimates. However, the effects of this contamination have not been quantified. Therefore, we developed a retractable masking device to allow more accurate measurement of canopy reflectance by excluding the contamination. We continuously observed canopy reflectance of a Japanese larch ( Larix kaempferi ) forest from a flux tower by using the device alternately in masked and unmasked modes. In this paper, we describe the design of the masking device and demonstrate how tower contamination affected the measured canopy reflectance. We found that the canopy reflectance in the visible spectral region was overestimated by a maximum of more than 3 times the actual value due to the tower contamination, but that the near-infrared reflectance was affected much less. The contamination effects were substantial and complex, and the magnitude varied depending on the wavelength, solar zenith and azimuth angles, weather conditions, and canopy phenological status. Consequently, vegetation indices calculated from the spectral data were greatly affected. For example, the contaminated Normalized Difference Vegetation Index was 8–22% lower than that obtained with the masking device. We conclude that to accurately measure canopy reflectance via wide-angle spectroradiometers or photosynthetically active radiation sensors, a masking device similar to the one described in this paper is strongly recommended.

Methane (CH4) fluxes were continuously measured in a temperate forest soil using six dynamic closed chambers with a laser-based analyzer. CH4 uptake increased with an increase in soil temperature and a decrease in volumetric water content, where multiple linear regressions using the two variables explained approximately 80% of the seasonal variations. Based on the measurements, our forest acted as an annual CH4 sink with a spatial variation of 25%. The calculated annual CH4 sink significantly decreased by increasing the chamber deployment period: 8–13 mg CH4 m−2 yr−1 min−1. The annual CH4 sink was significantly different using different calculation methods for the initial slope: 898 ± 11 mg CH4 m−2 yr−1 using a linear regression, 924 ± 8 mg CH4 m−2 yr−1 using a quadratic regression, and 975 ± 10 mg CH4 m−2 yr−1 using an exponential model. These results indicate that underestimations due to disturbing the CH4 gradient between chamber headspaces and soils were significant despite of the short deployment periods of 4–10 min. Chamber-based fluxes were consistent with canopy-scale CH4 fluxes by the micrometeorological hyperbolic relaxed eddy accumulation method: sink of 731 ± 38 to 888 ± 87 mg CH4 m−2 yr−1. Continuous dynamic closed chambers with laser-based analyzers are a powerful tool to understand CH4 fluxes in temperate forest soils, as long as a range of uncertainties are carefully evaluated.

Autumn leaf phenology and its color brightness provide valuable information for managing forest carbon cycles and cultural ecosystem services. Digital repeat photography has provided standard phenological data, but the methodologies for detecting autumn leaf coloring have various strengths and weaknesses. We assessed the accuracy, sensitivity, and uncertainty of various model and color index combinations for detecting autumn leaf coloring. Then we identified the most robust and sensitive methods, using digital repeat photography data from Japanese alpine vegetation. For determining autumn leaf color duration, quadratic or multinomial discriminant analysis using RGB digital numbers had the highest accuracy (hit ratio > 0.7). For determining the peak day of autumn leaf color and its color brightness, we compared uncertainty of methodologies by randomly resampling 80% of the data 20 times to mimic observation errors (e.g., due to heavy rain). The spline-fitted red/green reflectance ratio (RGR) and visible atmospherically resistant index (VARI) proved robust for detecting the peak day (median SD = 1.25). Uncertainty of color brightness was also low when using VARI fitted by a double logistic model for both red and yellow leaves (median coefficient of variation = 1.03). These two indexes are stable despite atmospheric effects, which may result in robustness to daily variation in conditions (e.g., fog). We compared sensitivity of leaf color brightness: RGR and excess red (ExR) fitted by a double logistic model had the highest sensitivity to red and yellow leaves exceeding the average of other combinations by 26% and 88% in median values, respectively. The small denominator or lack of a denominator of these indexes increases the sensitivity to red or yellow. Our results demonstrate the averaged accuracy, sensitivity, and robustness of each methodology among our research sites with different camera observations. These methods should help in utilizing hidden big data from web cameras or past photos that were not intended for scientific research to properly assess autumn leaf phenology and its color brightness.

Larch (Larix spp.) forests are predominantly distributed across high latitudes of Eurasia. They potentially have a strong influence on the terrestrial carbon and energy cycles, because of their vast area and the large carbon stocks in their peat soils in the permafrost. In this study, we elucidated intersite variation of ecosystem photosynthetic and respiratory parameters of eight larch forests in East Asia using the CarboEastAsia carbon flux and micrometeorology dataset. These parameters were determined using the empirical relationship between the carbon fluxes (photosynthesis and respiration) and micrometeorological variables (light and temperature). In addition, we examined leaf area index (LAI) determined by Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing data to explain the intersite variation. Linear or exponential relationships with annual mean temperature or seasonal maximum LAI at the study sites were found for the annual carbon fluxes (gross primary production [GPP] and total ecosystem respiration [RE]) as well as for four of the five seasonal maximum values of determined photosynthetic and respiratory parameters (maximum GPP at light saturation, initial slope of the light-response curve, daytime respiration, and RE at the reference temperature of 10 degrees C). Phenological indices, such as start day of the growing season, growing season length and growing season degree days explained much of the intersite variation of GPP and RE of the studied larch forests; however, the relationship between MODIS LAI and photosynthetic or respiratory parameters implies that the intersite variation in GPP and RE was caused not only by the temperature variation (abiotic factor), but also by the variation in the photosynthetic and respiration activity by vegetation (biotic factor) through the change in leaf (or whole vegetation) biomass. Our analysis shows that MODIS LAI serves as a good index to explain the variation of the ecosystem photosynthetic and respiratory characteristics of East Asian larch forests.

The datasets of net ecosystem CO2 exchange (NEE) were acquired from 21 forests, 3 grasslands, and 3 croplands in the eastern part of Asia based on the eddy covariance measurements of the international joint program, CarboEastAsia. The program was conducted by three networks in Asia, ChinaFLUX, JapanFlux, and KoFlux, to quantify, synthesize, and understand the carbon budget of the eastern part of Asia. An intercomparison was conducted for NEE estimated by three gap-filling procedures adopted by ChinaFLUX, JapanFlux, and KoFlux to test the range of uncertainty in the estimation of NEE. The overall comparison indicated good agreement among the procedures in the seasonal patterns of NEE, although a bias was observed in dormant seasons depending on the different criteria of data screening. Based on the gap-filled datasets, the magnitude and seasonality of the carbon budget were compared among various biome types, phenology, and stress conditions throughout Asia. The annual values of gross primary production and ecosystem respiration were almost proportional to the annual air temperature. Forest management, including clear-cutting, plantation, and artificial drainage, was significant and obviously affected the annual carbon uptake within the forests. Agricultural management resulted in notable seasonal patterns in the crop sites. The dataset obtained from a variety of biome types would be an essential source of knowledge for ecosystem science as well as a valuable validation dataset for modeling and remote sensing to upscale the carbon budget estimations in Asia.

We report long-term continuous phenological and sky images taken by time-lapse cameras through the Phenological Eyes Network ( http://www.pheno-eye.org . Accessed 29 May 2018) in various ecosystems from the Arctic to the tropics. Phenological images are useful in recording the year-to-year variability in the timing of flowering, leaf-flush, leaf-coloring, and leaf-fall and detecting the characteristics of phenological patterns and timing sensitivity among species and ecosystems. They can also help interpret variations in carbon, water, and heat cycling in terrestrial ecosystems, and be used to obtain ground-truth data for the validation of satellite-observed products. Sky images are useful in continuously recording atmospheric conditions and obtaining ground-truth data for the validation of cloud contamination and atmospheric noise present in satellite remote-sensing data. We have taken sky, forest canopy, forest floor, and shoot images of a range of tree species and landscapes, using time-lapse cameras installed on forest floors, towers, and rooftops. In total, 84 time-lapse cameras at 29 sites have taken 8 million images since 1999. Our images provide (1) long-term, continuous detailed records of plant phenology that are more quantitative than in situ visual phenological observations of index trees; (2) basic information to explain the responsiveness, vulnerability, and resilience of ecosystem canopies and their functions and services to changes in climate; and (3) ground-truthing for the validation of satellite remote-sensing observations.

The precision of current micrometeorological techniques has restricted their applications in measuring small methane (CH 4 ) fluxes in forest ecosystems. In this study, we continuously measured CH 4 fluxes using a state of the art laser-based gas analyzer and a hyperbolic relaxed eddy accumulation (HREA) method. The precision of the half-hourly fluxes was estimated at 2.93 nmol m −2 s −1 . The HREA method also contained uncertainties associated with scalar dissimilarity of 1.26 nmol m −2 s −1 . The precision was higher than those obtained in previous eddy covariance studies, because the HREA system did not require density fluctuation and high-frequency attenuation corrections. The observed CH 4 uptake decreased with increases in soil water content during the summer months. The estimated annual methane sink was 673 mg CH 4 m −2 yr −1 with uncertainties of ±231 mg CH 4 m −2 yr −1 . This annual methane sink increased to 868 mg CH 4 m −2 yr −1 with the application of friction velocity ( u * ) filtering. The uncertainties in gap-filling, storage correction, and scalar dissimilarity were less important than the uncertainties in the u * filtering. Our technique using the HREA method is a suitable tool for measuring small CH 4 fluxes in forest ecosystems, especially in remote sites where frequent maintenance is not practical.

We measured the methane flux of a forest canopy throughout a year using a relaxed eddy accumulation (REA) method. This sampling system was carefully validated against heat and CO2 fluxes measured by the eddy covariance method. Although the sampling system was robust, there were large uncertainties in the measured methane fluxes because of the limited precision of the methane gas analyzer. Based on the spectral characteristics of signals from the methane analyzer and the diurnal variations in the standard deviation of the vertical wind velocity, we found the daytime and nighttime precision of half-hourly methane flux measurements to be approximately 1.2 and 0.7 μg CH4 m−2 s−1, respectively. Additional uncertainties caused by the dilution effect were estimated to affect the accuracy by as much as 0.21 μg CH4 m−2 s−1 on a half-hourly basis. Diurnal and seasonal variations were observed in the measured fluxes. The biological emission from plant leaves was not observed in our studies, and thus could be negligible at the canopy-scale exchange. The annual methane sink was 835 ± 175 mg CH4 m−2 year−1 (8.35 kg CH4 ha−1 year−1), which was comparable to the flux range of 379–2,478 mg CH4 m−2 year−1 previously measured in other Japanese forest soils. This study indicated that the REA method could be a promising technique to measure canopy scale methane fluxes over forests, but further improvement of precision of the analyzer will be required.

Remotely sensed vegetation indices such as the normalized difference vegetation index (NDVI) or enhanced vegetation index (EVI) have been used to scale up flux-based gross primary production (GPP) measurements. Recently, the use of visible-band (VIS) indices for estimation of GPP has been proposed, and VIS_indices derived from digital cameras have been used for detecting phenological changes. To confirm the utility of remotely sensed VIS_indices for the evaluation of GPP in a Japanese larch forest, we investigated the relationships between flux-based GPP measurements and indices derived from both moderate resolution imaging spectroradiometer (MODIS) data and tower-mounted digital camera images. We evaluated the suitability of both traditional (NDVI and EVI) and VIS_indices (the greenred vegetation index (GRVI) and green ratio (GR)) at both satellite and near-surface scales for GPP estimation. We also used the MODIS data to evaluate the sensitivity of the indices to the effects of a severe forest disturbance. The results showed that VIS_indices had several advantages over the traditional indices: (1) seasonal variations in VIS_indices were more strongly correlated with GPP variations; (2) the vegetation growing season could be easily discriminated from the winter dormant period, because ground surface conditions affect VIS_indices less than they affect traditional indices; (3) the seasonal dynamics of vegetation could be determined at a satellite scale from MODIS data, and possibly even at a canopy scale from digital camera images; and (4) inter-annual variations of VIS_indices were likely to be more sensitive to vegetation changes after a disturbance. These results demonstrate the utility of VIS_indices for estimating GPP at satellite scales and possibly at the canopy scale. We suggest that multi-scale visible-band remote sensing could help our understanding of the ecosystem by improving the temporal and spatial resolutions of satellite data.

Diabetes is associated with a high prevalence of periodontal disease, but little is known about the effects of periodontal disease on incident diabetes. In total, 5848 non-diabetic individuals aged 30-59 yrs who completed a health examination were analyzed in this study. They were divided into three categories: no pathological pockets, moderate periodontitis, or severe periodontitis. Incident diabetes was defined as newly diagnosed cases with fasting plasma glucose > 125 mg/dL. Cox proportional hazards models estimated the effect of periodontitis on incident diabetes during a seven-year follow-up period. Moderate and severe periodontitis was significantly associated with an increased risk of diabetes in unadjusted analyses, but the magnitude of the association decreased after full adjustment [hazard ratio (HR) = 1.00, 95% confidence interval (95% CI) = 0.77-1.30 and HR = 1.28, 95% CI = 0.89-1.86, respectively]. Our findings do not indicate an apparent association between periodontitis and incident diabetes, although there was a tendency for increased risk.

Integration of CO2 flux observations with remote sensing technique and ecosystem modeling is expected to be useful for estimation of gross primary production (GPP). We focused on the changes in the two main parameters for the canopy-scale light–response curve—Pmax (maximum GPP at light saturation) and ϕ (initial slope)—as indicators to represent canopy photosynthetic capacity. We hypothesized that Pmax and ϕ could be evaluated by using spectral reflectance related to the changes in the levels of canopy nitrogen and chlorophyll. We analyzed the relationships between Pmax and ϕ, derived from tower-based CO2 flux observations, and ground-based spectral vegetation indices (VIs) in a temperate deciduous coniferous forest. The canopy-scale Pmax and ϕ showed clear seasonal changes accompanying phenological stages. Both the variations in Pmax and ϕ were strongly correlated with VIs, especially with the ratio vegetation index (RVI) and enhanced vegetation index (EVI), independent of the growth stages. Moreover, day-to-day short-term variations of Pmax and ϕ were affected by meteorological conditions such as vapor pressure deficit (VPD) and relative solar radiation which was calculated as the ratio of monitored radiation per theoretical maximum radiation. Thus, seasonal changes of Pmax and ϕ were effectively assessed by RVI or EVI, and their short-term variations were evaluated by the empirical relationships with VPD and relative solar radiation. We propose a new simple method for estimating GPP with good precision; by fitting the light–response function with the evaluated parameters, the estimated GPP reflects 3 types of temporal variation: diurnal, day-to-day, and seasonal.

著者人数: 13名, 資料番号: PA0910043000

The purpose of this study was to evaluate the relationships between diabetes and medical and dental care costs from a 5-yr prospective observation of Japanese workers. The data were derived from health and dental examinations and health insurance claims of 4,086 workers aged 40-54 yr. At baseline, the subjects were assigned to four categories: known diabetes; undiagnosed diabetes; impaired fasting glucose (IFG); and non-diabetic. The differences in health care costs among the non-diabetics, IFG and undiagnosed diabetes groups were not seen at baseline, but the costs incurred by the subjects with undiagnosed diabetes substantially increased thereafter. Over 5 yr of the study period, compared with the non-diabetic group, subjects with known diabetes incurred 3.9- and 2.9-fold higher annual inpatient and outpatient costs, respectively, while subjects in the undiagnosed diabetes group incurred 3.0- and 1.6-fold higher costs, respectively. There were no significant associations between annual dental care costs and diabetic status. The excess costs of medical care among subjects with diabetes were attributable to diabetes itself, heart disease and cerebrovascular disease, but not cancer. Among middle-aged workers, diabetics incurred significantly greater medical care costs than non-diabetics, whereas IFG was not associated with higher costs.

The aim of the study is to examine the relationship between toner-exposed work and health indices related to respiratory disorders and to confirm the baseline of a cohort study to clarify the effect of toner exposure in manufacturing plants. Subjects were 1614 male workers (809 toner-exposed workers and 805 referents) who were engaged in toner manufacturing plants in Japan (Fuji Xerox Co., Ltd). The age of subjects was from 19 to 59 years, and the average age was 40.2 years(median 40 years, SD 7.67). We conducted a pulmonary function test (PEFR, VC, FVC, FEV1.0%, V25/Ht) and a blood cell test (RBC, Hb, Hct, Plt, WBC, cell contents of WBC) and measured biochemical indices in blood (ALT, AST, γ-GTP, CRP, IgE) and 8-hydroxy-2’-deoxyguanosine (8-OHdG) in urine. Student t-test and logistic regression analysis were applied to compare between the toner-exposed workers and the referents and to analyze the relationship among indices of effects and independent factors. There was no significant difference between the two groups in blood cell count and biochemical indices. Inflammation- and allergy-related markers such as 8OHdG and IgE also showed no significant difference between toner-exposed workers and the referents. The influence of smoking on pulmonary function indices was observed, but there was no relationship between the pulmonary function and toner-exposed work. In this article, we report a preliminary cross-sectional analysis in the subjects of a cohort study. No difference in pulmonary function indices was observed between the toner-exposed workers and the referents, and there was no consistent relationship between the exposure status and examined indices; however, the prevalence of subjective respiratory symptoms was higher in the exposed workers as presented in another report. Further analysis is important in the ongoing cohort study to clarify the effect of toner exposure on respiratory systems.

ObjectiveWe investigated the relationship between the intake of fish and the risk of death from prostate cancer.DesignData were derived from a prospective cohort study in Japan. Fish consumption obtained from a baseline questionnaire was classified into the two categories of ‘low intake’ and ‘high intake’. The Cox proportional hazards model was used to estimate hazard ratios (HR) and 95 % confidence intervals.SubjectsData for 5589 men aged 30–79 years were analysed.ResultsA total of twenty-one prostate cancer deaths were observed during 75 072 person-years of follow-up. Mean age at baseline study of these twenty-one subjects was 67·7 years, ranging from 47 and 79 years old. Results showed a consistent inverse association of this cancer between the high v. low intake groups. The multivariate model adjusted for potential confounding factors and some other food items showed a HR of 0·12 (95 % CI 0·05, 0·32) for the high intake group of fish consumption.ConclusionsThese results support the hypothesis that a high intake of fish may decrease the risk of prostate cancer death. Given the paucity of studies examining the association between prostate cancer and fish consumption, particularly in Asian populations, these findings require confirmation in additional cohort studies.

Smoking has been established as an important risk factor for periodontal disease and tooth loss. The purpose of this study was a prospective evaluation of the effects of smoking on dental care utilization and its costs, based on data from 5712 males aged 20–59 yrs. Age, dental health behavior, and history of diabetes were adjusted in a multivariate analysis. Current smokers accrued 14% higher dental care costs than never-smokers over a five-year period. This difference in annual dental care costs was mainly attributable to the increased percentage of participants in the ‘higher dental care cost’ category among current smokers. There was no clear trend identified for the dose-dependent effects of smoking on dental care utilization and its costs. Past smokers incurred lower dental care costs compared with current smokers. Smoking may have played a key role in the increment of dental care utilization and its costs via deterioration in oral conditions.

Several studies have reported positive associations between oral infections and systemic diseases. The purpose of the present study was to evaluate the effects of oral symptoms on mortality from cardiovascular disease (CVD) and pneumonia. Using data from a cohort study in Japan, we analyzed 4,139 individuals aged 40–79 years. The baseline questionnaire included the following items related to oral symptoms: ‘sensitive teeth’, ‘difficulty in chewing tough food substances’, ‘bleeding gums’, and ‘mouth feels sticky’. We used the Cox proportional hazard model to estimate hazard ratios (HRs) and 95% confidence intervals (95%CIs) for mortality, after adjustments for lifestyle, socio-economic factors, and history of diseases. Persons complaining that their ‘mouth feels sticky’ had a two-fold higher risk of pneumonia (HR = 2.1; 95%CI, 1.2–3.6), while those complaining of ‘sensitive teeth’ had a lower risk of CVD (HR = 0.4; 95%CI, 0.2–0.9). Some oral symptoms may be predictors of mortality from pneumonia and CVD.

application/pdf, To clarify the utility of spectral vegetation indices (VIs) for estimating light conversion efficiency (e) in Japanese coniferous forests, we investigated the relationships between six VIs (NDVI, EVI, SAVI, PRI, CI, and CCI) and e in two mature monospecific forests of deciduous conifer (Japanese larch) and evergreen conifer (Japanese cypress) and one young mixed stand of deciduous conifer with evergreen undergrowth (hybrid larch and dwarf bamboo). In each forest canopy, we measured seasonal variations in CO2 flux, radiation environment, and visible–near-infrared spectral reflectance during 1 or 2 growing seasons.Wecalculated e as gross primary production (GPP) divided by the difference between incoming and reflected photosynthetically active radiation (PAR). VIs and e under clear skies were averaged between 11:00 and 13:00 JST and their relationships were analyzed. In the larch forest, all calculated VIs were positively correlated with e, and the highest correlation was that with CCI. Because of effects of extreme reduction in PRI in autumn with needle yellowing, the correlation of e and PRI was relatively small in this forest. In the cypress forest, on the other hand, no significant correlation was found except with PRI and CCI. The highest correlation in this forest was that with PRI, suggesting that the leaf biomass-related VIs based on near-infrared reflectance are not sufficient for estimating e of evergreen forest. In the mixed forest, with relatively sparse vegetation cover, all VIs were significantly correlated with e, but the best correlation was that with SAVI, possibly owing to the reduction in the effect of the reflectance from background soil. Correlation analysis of the pooled data from all forests showed the highest correlation between e and PRI. These results indicate that PRI is an effective VI in the remote estimation of e in both deciduous and evergreen forests, although there are some sensitivity differences between vegetation types.

Measurements of net ecosystem production (NEP) over forest stands were conducted from 11 flux towers in sub-arctic, temperate, and tropical regions in East Asia between 2000 and 2005. The sites extend over a wide latitude, ranging from 3 to 64 degrees N, and include sub-arctic and temperate needle-leaf deciduous forests (larch) (central Siberia, Mongolia, China, and northern Japan), temperate mixed, broadleaf deciduous, needle-leaf evergreen forests (northern and central japan), and seasonal and tropical rain forests (Thailand and Malaysia). The sub-arctic larch forests had short growing periods of 3-4 months. The temperate deciduous forests showed the greatest positive NEP after leaf expansion in early summer. Among the 11 sites, the maximum gross primary production (GPP) was observed in a temperate larch forest during the early stages of the growing period due to the high productivity of the larch species. The temperate evergreen sites displayed positive NEP earlier in the spring than the deciduous sites and had long growing periods (>10 months). The tropical seasonal forests showed negative NEP during the dry period from February to April, and turned positive after the rainy season started. The tropical rain forest showed a small flux (

The objective of this paper is to clarify what kind of environmental factors that regulate net ecosystem production (NEP), gross primary production (GPP), and ecosystem respiration (RE) in forest ecosystems across East Asia. Study sites were widely distributed and included diverse ecosystems, such as evergreen and deciduous, coniferous and broadleaf, planted and natural forests, from subarctic to tropical zones. We measured NEP using the eddy covariance technique at 13 forest sites in East Asia. Annual values of GPP and RE are simply regulated by annual mean air temperature across East Asia. There is a clear linear relationship between annual GPP and annual mean air temperature because the air temperature influences both growing period length and the seasonal variation of the maximum photosynthetic capacity, which, together, regulate the annual GPP. On the other hand, there is a strong exponential relationship between annual RE and annual mean air temperature on an East Asia scale, which is quite similar to the relation obtained on a canopy scale. The dependency of annual RE on air temperature on the East Asia scale was similar to that of monthly RE on air temperature on an individual site scale excepting for temperate larch and mixed forests in northern Japan. The reason why the relation is simple is that severe stress, which affects GPP or RE, is small in East Asia. The present study suggests that RE is sensitive to non-climate environmental factors when compared to GPP, thus the annual RE-air temperature relationship is more scattered than the annual GPP-air temperature relationship. The NEP is small at high latitude, relatively large at mid-latitude, and scattered at low latitude. As a whole, the NEP is more influenced by RE than GPP in East Asia. Compared to North America and Europe, the increase in the ratio of GPP to air temperature is slightly higher in East Asia. One of the possible reasons for this is that GPP in East Asia is not exposed to severe environmental stresses, such as summer drought.

Purpose To examine the relation of green tea consumption with oral carcinogenesis, we prospectively analyzed data from a nationwide large-scale cohort study in Japan. Methods A total of 20,550 men and 29,671 women aged 40–79 years, without any history of oral and pharyngeal cancer at baseline survey, were included in the present study. During a mean follow-up period of 10.3 years, 37 oral cancer cases were identified. The Cox proportional hazard model was used to estimate the hazard ratio (HR) and 95% confidence interval (95% CI) for oral cancer according to green tea consumption by sex, while adjusting for age, smoking, alcohol drinking, and other dietary factors. Results For women, the HRs of oral cancer for green tea consumption of 1–2, 3–4, and 5 or more cups per day were 0.51 (95% CI: 0.10–2.68), 0.60 (95% CI: 0.17–2.10), and 0.31 (95% CI: 0.09–1.07), respectively, compared with those who drank less than one cup per day ( p for trend, 0.08). For men, no such trends were observed. Conclusions Our findings did not suggest a prominent inverse association of green tea consumption with oral cancer, although there was a tendency for a reduced risk in women.

Purpose: The Oral Health Impact Profile (OHIP) is one of the most widely used instruments to measure oral health-related quality of life (OHRQoL). The aim of this study was to evaluate the reliability and validity of a Japanese short version of the Oral Health Impact Profile (OHIP-JP16) for prostheses.Methods: Data were collected by means of self-administered questionnaires from July 2004-November 2005 at 4 dental offices located in Japan. The questionnaires consisted of self-perceived oral health status, need for treatment, and the OHIP-JP16 score. The total target sample consisted of 137 patients, of which 125 patients answered all the 16 items in the questionnaires. The reliability was assessed in terms of internal consistency and reproducibility.Results: Cronbach’s alpha of the OHIP-JP16 subscales ranged from 0.43 to 0.93. The reproducibility of test-retest reliability was analyzed (n=12). The test-retest reliability was measured by the intra-class correlation coefficient (ICC) and kappa index. The ICC ranged from 0.69-0.92 and kappa index ranged from 0.12-0.67. The internal consistency and reproducibility demonstrated quite a good reliability. Discriminative validity was examined by comparing total scores among groups according to the following parameters: number of teeth (more than 24 and less than 23), Eichner index (A, B, and C group), denture wearing (with and without dentures), and self-perceived oral health (good and poor). The patients who had more than 24 teeth, were in group A of the Eichner index, those without dentures, and having good oral health had better OHIP-JP16 total scores (P

Although the relationship between lifestyle and subjective symptoms has been reported in the general population, relatively few studies have looked at the link between these two in workplace. To investigate the relationship between lifestyle and subjective symptoms, a cross-sectional study was carried out using data from 4,540 workers aged 20-69 years old in a food products company. The subjective symptoms with a prevalence of more than 10% in either males or females were selected as dependent variables: fatigue, dropsical swelling of hands or feet, stiff neck or shoulders, backpain, deterioration of eye sight, dizziness, diarrhea and constipation. We used a multiple logistic regression model to calculate the odds ratio(OR) and 95% confidence interval(CI) for each subjective symptom according to lifestyle: regular physical activity, proper sleeping, nine hours or less of work, having breakfast, having a nutritionally balanced diet, no smoking and moderate drinking of alcohol. We adjusted for age and type of occupation by gender. The findings confirmed the relationship between smoking and alcohol drinking and subjective symptoms in both genders. In addition, proper sleeping was likely to prevent musculoskeletal symptoms in females.

BACKGROUND: Several epidemiologic studies reported the positive association between cigarette smoking and stomach cancer. The prevalence of smoking in men remains high in Japan compared to other developed countries. It is therefore of great importance to determine the impact of cigarette smoking on stomach cancer among the Japanese population. The Japan Collaborative Cohort Study (JACC Study) provided an opportunity to examine the association between smoking and the risk of mortality due to stomach cancer.METHOD: A baseline survey was conducted throughout Japan from 1988 through 1990 among 110,792 inhabitants of 45 areas. Data retrieved for 98,062 participants (43,482 male and 54,580 female) who provided sufficient information about their smoking habits, without any history of caner at the baseline. Of total 970,251 person-years, 757deaths due to stomach caner were identified.RESULTS: Current smokers were at a higher risk of death due to stomach cancer than non-smokers (Hazard ratio = 1.36; 95% confidence interval [CI]: 1.07, 1.73). The risk of stomach cancer for men who smoked 15 or more cigarettes per day was approximately 1.4-fold greater than that of non-smokers, and those who smoked 35 or more cigarettes per day had an approximately 1.7-fold higher risk of stomach cancer, although the dose-response trend among men was unclear (p for trend = 0.063). No associations between smoking and stomach cancer were detected among women.CONCLUSION: The present results, together with previous findings, strongly support a hypothesis that cigarette smoking increases the risk of stomach cancer in Japanese men.J Epidemiol 2005; 15: S113-S119.

Background. This prospective cohort study examined the association between educational level and major causes of death in Japan. Method. A baseline survey was conducted between 1988 and 1990 among 110,792 inhabitants of 45 areas aged 40–79 years. Follow-up surveys were conducted annually and causes of death were identified from death certificates. The analysis was restricted to 16,715 men and 23,284 women. Results. During the follow-up period (377,139 person-years), 6628 deaths were recorded. Individuals with low levels of education had an increased overall risk of death [relative risk (RR) = 1.16, 95% confidence interval (CI): 1.08, 1.25, in men; RR = 1.26, 95% CI: 1.14, 1.39, in women], cancers (RR = 1.17, 95% CI: 1.04, 1.32, in men; RR = 1.10, 95% CI: 0.93, 1.30, in women), and death from external causes (RR = 1.81, 95% CI: 1.29. 2.54, in men; RR = 1.78, 95% CI: 1.18, 2.70, in women). Ischemic heart disease risk was marginally reduced in men with low levels of education (RR = 0.77, 95% CI: 0.58, 1.01). Conclusions. These results show that health inequalities exist in Japan, even though wealth inequalities are relatively low. Social and political initiatives will be needed to correct these inequities between different socioeconomic statuses.

– An oral health promotion program has been conducted since 1989 at a shipyard in Japan. Aims: The purpose of the present study was to assess the impact of oral health promotion in the workplace in terms of dental care costs and frequency of dental visits. Methods: This program consisted of orientation, an initial regimen, and group counseling. The initial regimen included an evaluation of each participant’s oral health status, and instruction concerning oral hygiene, and prevention of oral disease. The participants were selected with each unit being a preexisting peer group. Eighty-seven participants were compared with 216 control subjects in terms of annual dental care costs and frequency of dental visits in four periods: the 1-year period before the program, the 1st year after the program, the 2nd year after, and the 3rd year after. Results: The annual mean dental care cost in the participant group for the year prior to the program was higher than that in the control group (21 317 vs. 17 116 yen). In the 1st year after the program, the difference increased (26 642 vs. 19 481 yen). In the 2nd and 3rd years after the program, dental care costs in the participant group were lower than those in the control group (2nd year: 18 305 vs. 22 841 yen, 3rd year: 16 911 vs. 21 920 yen). Conclusions: It can be concluded that this oral health promotion program in the workplace contributed to saving of costs associated with dental care. The workplace can be regarded as a key area for implementation of an oral health care system to make good use of limited resources.

OBJECTIVE As there are reports that ultrafine particles are generated by thermal printer toner, and that mucosal irritation symptoms were observed in users. When printers were operated, we have been examining the effects of not only toner but its by-products on human health. METHODS We conducted a review of epidemiological and animal data on toner and its by-products such as ultrafine particles and volatile organic compounds (VOC). This was the second survey and it confirmed the results of the first survey. RESULTS We reviewed the data, and summarized the results as follows. 1) Four cross-sectional studies reported no definite harmful effects of toner. 2) Ultrafine particles were generated in greater numbers at higher fuser heating and higher toner coverages. Ultrafine particles were also observed at lower rates in idle mode. 3) High-sensitive c-reactive protein in serum and heart rate variability (HRV) were useful biomarkers of not only exposure to ultrafine particles but disorder of cardiovascular disease, 8-hydroxydeoxyguanosine in urine is a biomarker of acute lung injury by welder fume, and VEGF and CA15-3 are highly sensitive and specific biomarkers of pulmonary fibrosis. 4) Physico-chemical properties of ultrafine particles were examined, and specific parameters related to pulmonary responses were not observed. CONCLUSIONS Taken together, we found that there are some biomarkers which are related to not only exposure and but disorders induced by ultrafine particles, and that the generation of ultrafine particles with the operation of printers was associated with other factors than the fixing process. Until now there has been insufficient data for estimation of the hazards of toner and its by-products. However, continuing examinations are useful for complementing and correcting the information and data on toners and for revising the measures of occupational health. We will continue these examinations of toner and its by-products in the future.

Background: We estimated the burden of cancer using mortality and years of life lost according to life tables in a cohort study in Japan. Methods: A cohort of 13 270 subjects established in the late 1980s in Japan was followed annually for the vital status of all subjects until 2003. For subjects who died, the underlying cause of death was ascertained from the death certificate. Crude mortality rate from cancer per 100 000 person-years was calculated, and years of life lost (YLL) as well as the average years of life lost (AYLL) were computed using the 1995 life tables in Japan. Results: During the follow-up period, we recorded a total 839 cancer deaths (517 men and 322 women), representing 35.5% of deaths from all causes. Overall crude cancer mortality was 654.9 per 100 000 person-years in men and 312.6 in women. Total YLL due to cancer was 7035.3 years in men and 5627.0 years in women. Overall AYLL due to all cancers was 13.6 years less than life expectancy in men and 17.5 years in women. Conclusion: These results showed that cancer was the leading cause of death in this cohort; with stomach, liver and lung cancer the three most frequent cancers in both sexes. YLL and AYLL reflect the cost of dying from cancer in terms of years of life expectancy lost. The different mortality statistics used here may be useful in public health considerations of cancer burden.

We need a new investigation of the effect of not only toner but also of its by-products on human health, because of the generation of fine particles and the release of volatile organic compounds (VOC) in the process of photocopy. Therefore, we gathered epidemiological and animal data on toner and its by-products, and examined the occupational health management of toner. We examined the effect of carbonblack as the main component of toner, and titanium dioxide and amorphous silica as surface-adhesive nanomaterials, and VOC on human health, and reviewed them. We summarize the results as follows. 1) High sensitive c-reactive protein in serum, 8-hydroxydeoxyguanosine in urine, and heart rate variability (HRV) are useful for biological monitoring of exposure to toner and its by-products. 2) Particle number concentrations have been often measured by scanning mobility particle sizer (SMPS) compared with other apparatus, although this is not measurement gold standard. Taken together, we have examined whole occupational health management of toner and its by-products.

Due to the potential for an influenza pandemic, preparedness for infection control in healthcare settings is essential from the standpoint of occupational health for healthcare workers. We conducted questionnaire surveys among Japanese hospitals to assess preparedness at the individual and institutional levels and their inter-relationship. Questionnaires were administered at 7 tertiary hospitals in Japan during the spring of 2006. We analyzed 7,378 individual responses of the 10,746 questionnaires administered and all seven institutional responses by hospital infection control committees. Healthcare workers assigned low importance to personal protective equipment and showed mixed attitudes (anxious but accepting) to the potential risk. Institutional gaps existed in preparedness across hospitals and most hospitals lacked the specificity to cope with a pandemic. A higher level of institutional preparedness, as determined by expertise as well as general and specific countermeasures, was an important predictor of individual recognition of preventive measures, perception of institutional measures, and attitude toward coping with risk. A higher level of institutional preparedness stood out to be an important predictor of individual preparedness. Considering the risk of a future influenza pandemic, hospitals should improve preparedness at all levels.