Masaji Ono

Respiratory Health Associated with Exposure to Automobile Exhaust. I. Results of Cross-sectional Studies in 1979, 1982, and 1983

Three cross-sectional studies were conducted in an effort to investigate the effect of automobile exhaust on respiratory symptoms. Female adult subjects were selected from residents who lived near roadways that were subjected to very heavy traffic. A standard questionnaire was administered to approximately 5,000 people. Distances of the residences from the roadside were adopted as an index of exposure to automobile exhaust. The estimated odds ratios for chronic cough, chronic phlegm, chronic wheeze, shortness of breath, and chest cold with phlegm, relative to distance from the roadside--adjusted by age, smoking status, years at residence, occupation, and type of home heating-ranged from 0.76 to 2.75. The 95% confidence limits of the odds ratios for chronic cough and chronic phlegm excluded or approached 1.00 in each of the studies. This suggests that exposure to automobile exhaust may be associated with an increased risk of certain respiratory symptoms.

Risk Factors for Nuclear Lens Opacification: The Reykjavik Eye Study

PURPOSE The purpose of this study is to examine risk factors for nuclear lens opacification in citizens of Reykjavik. METHODS 1,045 persons, 583 females and 462 males aged 50 years and older, were randomly sampled and underwent a detailed eye examination and answered a questionnaire. In all Scheimpflug photography of the anterior eye segment was done including the lens as well as retroilluminated photography of the lens. These photographs were used for the diagnosis of lens opacification. The data was analyzed using a logistic regression model. RESULTS An increased risk for all grades of nuclear opacifications was found with ageing (OR = 1.228, 95% CI = 1.192-1.264, p = 0.000), cigarette smoking for more than 20 pack/years (OR = 2.521, 95% CI = 1.521-4.125, p = 0.000) and pipe or cigar smoking (OR = 2.478, 95% CI = 1.200-5.116, p = 0.014). Outdoor exposure, cortical lens opacification grade II and III and computer usage were not found to be linked to higher risk of nuclear opacification. No correlation was found between nuclear opacification and the consumption of vitamins, herring, sardines and shrimps, cod-liver oil or plant oil, nor were iris color, hyperopia, systemic steroid use, cardiovascular disease, diabetes, glaucoma and pseudoexfoliation found to have a significant effect. CONCLUSIONS Ageing is a major risk factor for nuclear lens opacification, and smoking is a major modifiable risk factor. Cortical and nuclear lens opacifications do not share the same modifiable risk factors.

The Reykjavik Eye Study--prevalence of lens opacification with reference to identical Japanese studies.

Purpose: A population-based cataract epidemiological study, the Reykjavik Eye Study, was conducted to determine the prevalence and characteristics of lens opacities in Iceland. The results were compared with those from previous surveys in Japan to determine the influence of race and environmental factors. Methods: 1,635 randomly selected residents of Reykjavik, Iceland, were enrolled, and among them, 1,045 responded and took part in the study. The subjects received ophthalmological examination of both the anterior and the posterior segments. Changes in the crystalline lens were examined and photographed under maximal pupillary dilation. Classification of the opacity types and grading of the extent of lens opacificiation were done using a standardized scheme, and the data were analyzed with Student’s test, the χ2 test and the Mantel-Haenszel test. Results: The prevalence of lens opacities in subjects in their 50s, 60s, 70s and in those 80 years and older was 42.7, 61.0, 85.3 and 100%, respectively. Grade II and III lens opacities were found in 2.2% of subjects in their 50s and in 10.5, 35.9 and 62.3% in their 60s, 70s, and over 80 years, respectively. Cortical opacities predominated in all age groups followed by nuclear opacities; subcapsular opacities, on the other hand, were quite rare. A unique type of opacity, i.e., granular opacity, seldom seen among the Japanese, was found in 6.6% of the Icelandic subjects. Conclusions: Our results show that cortical opacity is the major type of opacity in Icelandic subjects, although its prevalence was lower than that in the Japanese subjects. Interestingly, the first appearance of lens opacities of grades II and III in Icelanders was delayed by 10 years compared to the Japanese suggesting fewer or less severe risk factors for cataract formation in Iceland.

Intracerebral haemorrhage associated with hourly concentration of ambient particulate matter: case‐crossover analysis

Aims: To examine the association of hourly time lagged concentration of ambient particulate matter and death due to stroke. Methods: Mortality data for five years (January 1990 to December 1994) were obtained from the Ministry of Health, Labour, and Welfare of Japan. Data were used only if the deceased was 65 years old or older at the time of death, if death was attributed to intracerebral haemorrhage or ischaemic stroke, and if the deceased lived in one of 13 major urban areas. Hourly mean concentrations of PM7, NO2, and photochemical oxidants were measured at monitoring stations in the 13 areas. Time stratified case-crossover analysis was used to examine the data for evidence of triggering stroke mortality. Results: The 1-hour mean concentration of PM7 measured about 2 hours before death was associated with the risk of death due to intracerebral haemorrhage from April to September (odds ratio = 2.40, 95% CI 1.48 to 3.89, for exposure to PM7 of more than 200 μg/m3 (threshold)). The higher risk was independent of the 24-hour mean concentration of PM7. PM7 was not associated with death due to ischaemic stroke. Conclusions: Transiently high concentrations of PM7 are associated with death due to intracerebral haemorrhage. Air quality standards or guidelines for particulate matter should be based not only on 24-hour mean concentrations, but also on hourly data.

Myocardial infarction deaths after high level exposure to particulate matter

Study objective: To examine the short term effects of raised concentrations of air pollutants on myocardial infarction deaths, the authors measured if incidence rate ratios increased after the concentration of suspended particulate matter (SPM) reached various critical values and were sustained for various periods of time. Design: Retrospective analysis of a database, which contained hourly SPM concentrations and myocardial infarction deaths. Methods: The rate of death (events/1000 hours) attributable to myocardial infarction was compared among SPM categories. SPM categories were classified by five different critical values that measured high SPM levels, and by the hours of exposure (exposure window) after reaching the critical SPM level. Main outcome measures: The adjusted incidence rate ratios in the various SPM categories were compared with the reference category (0–99 μg/m3) to determine the incidence rate ratio. Setting: Tokyo Metropolitan area, Japan. Patients/participants: 14 950 people who died of myocardial infarction in the Tokyo Metropolitan area from 1990 to 1994. Main results: When the exposure window was one hour, the adjusted incidence rate ratio in each category were 1.13 (95% CI: 1.07 to 1.20) in the 100–149 μg/m3 category, 1.17–1.24 in the intermediate categories, and 1.40 (1.00 to 1.97) in the highest (300 μg/m3 over) category. When the exposure window was one to six hours, increased rate ratios were seen in the highest category (1.17 (four hours) to 1.40 (one hour)). Gradual increases in the incidence rate ratio were seen as the SPM category increased when the exposure window was less than six hours. Conclusion: An increased rate ratio of myocardial infarction deaths was seen within a few hours after reaching a high concentration of SPM. When the exposure window was less than six hours, there was a gradual increase in the incidence rate ratio as the SPM concentration increased.

Prevalence of Primary Cornea guttata and Morphology of Corneal Endothelium in Aging Japanese and Singaporean Subjects

The purpose of the present study was to examine, in the aging people, racial and gender differences in the morphology of corneal endothelium as well as the incidence of cornea guttata in two Asian subject groups, one in Singapore and the other in Japan. Four hundred and sixty-five Chinese Singaporeans and 299 Japanese subjects (residents of Monzen-machi, Ishikawa Prefecture) aged 50 years and older were recruited for the study. Corneal endothelial abnormalities were diagnosed with slit-lamp biomicroscopy and specular microscopy. Primary cornea guttata appeared as beaten metal appearance in slit-lamp images and dark regions in specular images. In addition to cornea guttata, corneal endothelial morphology was also analysed with specular microscopy. The mean cell density was 2,808/mm2 in the Japanese subjects which was significantly higher than the 2,718/mm2 seen in the Singaporeans (p < 0.001). The incidence of cornea guttata was significantly higher in the Singaporeans than in the Japanese individuals and also higher in women than in men of both racial groups. These differences support not only a racial and a gender factor but also a possible environmental influence.

The Japan Environment and Children's Study (JECS): A Preliminary Report on Selected Characteristics of Approximately 10 000 Pregnant Women Recruited During the First Year of the Study

BACKGROUND The Japan Environment and Childrens Study (JECS) is an ongoing nationwide birth cohort study launched in January 2011. In this progress report, we present data collected in the first year to summarize selected maternal and infant characteristics. METHODS In the 15 Regional Centers located throughout Japan, the expectant mothers were recruited in early pregnancy at obstetric facilities and/or at local government offices issuing pregnancy journals. Self-administered questionnaires were distributed to the women during their first trimester and then again during the second or third trimester to obtain information on demographic factors, physical and mental health, lifestyle, occupation, environmental exposure, dwelling conditions, and socioeconomic status. Information was obtained from medical records in the first trimester and after delivery on medical history, including gravidity and related complications, parity, maternal anthropometry, and infant physical examinations. RESULTS We collected data on a total of 9819 expectant mothers (mean age = 31.0 years) who gave birth during 2011. There were 9635 live births. The selected infant characteristics (singleton births, gestational age at birth, sex, birth weight) in the JECS population were similar to those in national survey data on the Japanese general population. CONCLUSIONS Our final birth data will eventually be used to evaluate the national representativeness of the JECS population. We hope the JECS will provide valuable information on the impact of the environment in which our children live on their health and development.Background The Japan Environment and Children’s Study (JECS) is an ongoing nationwide birth cohort study launched in January 2011. In this progress report, we present data collected in the first year to summarize selected maternal and infant characteristics. Methods In the 15 Regional Centers located throughout Japan, the expectant mothers were recruited in early pregnancy at obstetric facilities and/or at local government offices issuing pregnancy journals. Self-administered questionnaires were distributed to the women during their first trimester and then again during the second or third trimester to obtain information on demographic factors, physical and mental health, lifestyle, occupation, environmental exposure, dwelling conditions, and socioeconomic status. Information was obtained from medical records in the first trimester and after delivery on medical history, including gravidity and related complications, parity, maternal anthropometry, and infant physical examinations. Results We collected data on a total of 9819 expectant mothers (mean age = 31.0 years) who gave birth during 2011. There were 9635 live births. The selected infant characteristics (singleton births, gestational age at birth, sex, birth weight) in the JECS population were similar to those in national survey data on the Japanese general population. Conclusions Our final birth data will eventually be used to evaluate the national representativeness of the JECS population. We hope the JECS will provide valuable information on the impact of the environment in which our children live on their health and development.

Estimating Mortality Effects of Fine Particulate Matter in Japan: A Comparison of Time-Series and Case-Crossover Analyses

Abstract Small particles can reach alveoli without being trapped in the upper respiratory tract and may have a greater impact on health than larger particles. Given the limited knowledge on health effects of fine particulate matter (PM2.5) in Japan, the short-term effects of PM2.5 on daily mortality using the generalized additive model (GAM), generalized linear model (GLIM), and time-stratified case-crossover analysis were estimated. Daily mortality data were obtained from the Ministry of Health, Labor, and Welfare. Air pollution and meteorological data in 20 areas were obtained from the National Institute for Environmental Studies and the Japan Meteorological Agency, respectively. The three methods were compared, adjusting for meteorological variables and co-pollutants, for area-specific analyses and combined area-specific results using meta-analysis with a random-effects model. Daily mortality for elderly aged 65 and over varied from 0.5 to 127.3 by area. The 24-hr mean concentration of PM2.5 ranged from 11.8 to 22.8 μg/m3. Area-specific analyses revealed regional heterogeneity. Furthermore, combined results showed that a 10-μg/m3 increase in PM2.5 for the single-pollutant model at lag1 was associated with a 0.53, 0.77, and 0.88% increase in all-cause mortality for the GAM, GLIM, and case-crossover analysis, respectively. These findings provide robust evidence for the short-term effects of air pollutants on daily mortality in Japan and suggest that differences in estimates obtained from different statistical models should be considered when multipollutant models are used.

Lifestyle Factors and Visible Skin Aging in a Population of Japanese Elders

Background The number of studies that use objective and quantitative methods to evaluate facial skin aging in elderly people is extremely limited, especially in Japan. Therefore, in this cross-sectional study we attempted to characterize the condition of facial skin (hyperpigmentation, pores, texture, and wrinkling) in Japanese adults aged 65 years or older by using objective and quantitative imaging methods. In addition, we aimed to identify lifestyle factors significantly associated with these visible signs of aging. Methods The study subjects were 802 community-dwelling Japanese men and women aged at least 65 years and living in the town of Kurabuchi (Takasaki City, Gunma Prefecture, Japan), a mountain community with a population of approximately 4800. The facial skin condition of subjects was assessed quantitatively using a standardized facial imaging system and subsequent computer image analysis. Lifestyle information was collected using a structured questionnaire. The association between skin condition and lifestyle factors was examined using multivariable regression analysis. Results Among women, the mean values for facial texture, hyperpigmentation, and pores were generally lower than those among age-matched men. There was no significant difference between sexes in the severity of facial wrinkling. Older age was associated with worse skin condition among women only. After adjusting for age, smoking status and topical sun protection were significantly associated with skin condition among both men and women. Conclusions Our study revealed significant differences between sexes in the severity of hyperpigmentation, texture, and pores, but not wrinkling. Smoking status and topical sun protection were significantly associated with signs of visible skin aging in this study population.

Association between traffic-related air pollution and development of asthma in school children: Cohort study in Japan

Air pollution is widely understood to be capable of exacerbating asthma symptoms. Here we examined the association between traffic-related air pollution and development of asthma in school children. Subjects were 10,069 school children in their first through third years of compulsory education (6–9-year old). The main outcome was incidence of asthma as determined from the questionnaire. Follow-up surveys were conducted every year up to 4 years after the end of the study. To evaluate individual level of exposure to traffic-related air pollution, we used a simulation model that accounted for exposure level both at home and at school. As surrogates of traffic-related air pollution, the estimation target was the annual average individual exposure of automobile exhaust-originating nitrogen oxides (NOx) and elemental carbon (EC). Confounding factors were adjusted using a discrete-time logistic regression model. We found a positive association between exposure to EC and incidence of asthma. The odds ratio (OR) (95% confidence interval) for asthma incidence was 1.07 (1.01–1.14) for each 0.1 μg/m3 EC and 1.01 (0.99–1.03) for each 1 p.p.b. NOx. Traffic-related air pollution is associated with development of asthma in school children.