BackgroundThe Japan Environment and Children’s Study (JECS), known as Ecochil-Chosa in Japan, is a nationwide birth cohort study investigating the environmental factors that might affect children’s health and development. We report the baseline profiles of the participating mothers, fathers, and their children.MethodsFifteen Regional Centres located throughout Japan were responsible for recruiting women in early pregnancy living in their respective recruitment areas. Self-administered questionnaires and medical records were used to obtain such information as demographic factors, lifestyle, socioeconomic status, environmental exposure, medical history, and delivery information. In the period up to delivery, we collected bio-specimens, including blood, urine, hair, and umbilical cord blood. Fathers were also recruited, when accessible, and asked to fill in a questionnaire and to provide blood samples.ResultsThe total number of pregnancies resulting in delivery was 100,778, of which 51,402 (51.0%) involved program participation by male partners. Discounting pregnancies by the same woman, the study included 95,248 unique mothers and 49,189 unique fathers. The 100,778 pregnancies involved a total of 101,779 fetuses and resulted in 100,148 live births. The coverage of children in 2013 (the number of live births registered in JECS divided by the number of all live births within the study areas) was approximately 45%. Nevertheless, the data on the characteristics of the mothers and children we studied showed marked similarity to those obtained from Japan’s 2013 Vital Statistics Survey.ConclusionsBetween 2011 and 2014, we established one of the largest birth cohorts in the world.

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.

BackgroundThe 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.MethodsIn 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.ResultsWe 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.ConclusionsOur 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.

This study suggests that an increase in temperature has a short-term effect on suicide mortality in Japan.

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