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We observed trends in the height of children aged 3 to 6 in Japan using data from the National Growth Survey on Preschool Children in the years 1990, 2000, and 2010. Average standard deviation (SD) scores of height decreased from 0.39 (SD 1.02) in 1990 (n = 3,684) to 0.37 (SD 1.05) in 2000 (n = 2,981) and 0.33 (SD 1.07) in 2010 (n = 2,027). Mothers of children in later waves were taller, older, and more likely to be primiparous; children in later waves had shorter gestational age, lower birth weight, and were less likely to have been fed less with formula or solid foods before 6 mo. The only factor that consistently contributed to a reduction in children’s height for both 1990–2000 and 2000–2010 was a reduction in birthweight SD score (indirect effect on height –1.5 [95% CI: –1.9, –1.1] mm for 1990–2000 and –1.2 [95% CI: –1.8, –0.8] mm for 2000–2010). Factors that contributed, although not significantly or consistently between the two periods, were changes in pre-pregnancy BMI, smoking during pregnancy, multiple pregnancies, gestational age, BMI at birth, and use of formula and solid foods before 6 mo. Secular increases in maternal age, height, and primiparity contributed to increasing children’s height.

Background: The thyroid ultrasound examination (TUE) program was initiated among the residents of Fukushima Prefecture aged ≤18 years at the time of the Fukushima Dai-ichi Nuclear Power Plant accid...

Background Large changes in height standard deviation score (SDS) have been reported from birth to 3 years of age. We analyzed how early these changes start and whether they are affected by nutrition. Methods The longitudinal growth of 1,849 children born between March 1 2007 and August 31 2007 or between March 1, 2009 and August 31 2009 with five records from birth to 3 years of age was analyzed. Results The height SDS at birth was positively correlated with body mass index (BMI) SDS at birth (r = 0.224, P < 0.0001). The height SDS at birth decreased among children with a positive height SDS and increased among children with a negative height SDS. The changes occurred immediately after birth and became more modest as children aged. Regarding the change in the height SDS from birth to 3 years of age, 33.4% of children increased more than 0.5 SDs, 39.8% of children decreased more than 0.5 SDs, and 34.4% of children remained within ±0.5 SDs. The change in height SDS displayed a strong positive correlation with the change in weight during the four periods. From birth till 3 months, from 3 months till 6 months, from 6 months till 1.5 years, and from 1.5 years till 3 years. Conclusions The significant positive correlation between height SDS and BMI SDS suggests an effect of children’s nutrition status in utero. The height SDS change started immediately after birth and the change was largest from birth to 3 months. A positive correlation between changes in height SDS and weight suggest that growth during early childhood depends on nutritional status.

Current status and its background of Adult Turner Syndrome (TS) are not clarified well. Via a questionnaire survey of 492 adult women with TS, this study investigated the association between menstruation, Kaufmann therapy (menstrual induction therapy), social status (education, employment & marriage), complications, transition from pediatric to adult care, and sex chromosome karyotype using statistical methods. Spontaneous menarche occurred in 22.0% and more frequently among patients with the 45,X/46,XX karyotype. Over 60% of these subjects, menstruation did not persist regularly. Kauffmann therapy was performed in 69.4%; the most common formulation was a conjugated estrogen and progesterone combination. Marriage and higher education advancement rates were low in adults with TS, whereas their employment rate was similar to that of the age-matched general female population. Patients receiving Kauffmann therapy had higher complication rates, greater education length, and higher employment rates. The higher-education advancement rate was observed among patients with 45,X/46,X,Xi and 46,X,Xi karyotypes. Transition from pediatrician to adult specialist was not smooth, subjects were treated in pediatric departments (60.7%), gynecological department (21.4%), internal medicine departments (13.3%), and others. While reason is not clear, the largest number of TS patients are treated in general pediatrics and the percentage of receiving Kauffmann therapy and having complication were significantly lower than in pediatric and adult department of endocrinology (& metabolism). This Study revealed many novel findings of adult TS.

Existing guidelines recommend long-term follow-up of childhood cancer survivors (CCS). However, in Japan, transitional care for CCS has not been established. To ascertain the current status in Japan, and to cultivate a better understanding, a questionnaire survey was conducted on transitional care in CCS, and adolescent and young adult (AYA) cancer survivors. Questionnaires were distributed to 183 councilors (137 institutions) of the Japanese Society for Pediatric Endocrinology. A total of 131 responses, representative of 174 councilors, were obtained. The response rate was 95%. Among the respondents, 91% had experience in medical care for cancer patients, while 63% had experience in transitional care; however, the number of patients referred to adult clinics was small. Further, 89% acknowledged the availability of adult endocrinologists who were willing to accept these patients; although their numbers were insufficient. Pediatric endocrinologists highlighted difficulties in medical examinations concerning infertility, obesity, pregnancy/delivery, and gonadal dysfunction, in that order. Staff and time shortages were listed as some of the challenges faced by medical staff, while multisystem morbidity was listed for patients. This nationwide questionnaire survey revealed that Japanese pediatric endocrinologists require cooperation between related departments and collaborative infrastructure to develop transitional care for cancer survivors.

Growth hormone (GH) deficiency (GHD) in children is a heterogeneous condition that includes several entities of various severities. GH treatment has been affected by various factors. Because comprehensive analyses for Japanese children with GHD over time are scarce, we investigated the baseline characteristics of patients with GHD at the start of GH treatment between 1996 and 2015 using data from the Foundation for Growth Science in Japan. During the registration period, 19,717 subjects were determined to be eligible for GH treatment as GHD. Overall analyses revealed that there were twice the number of male patients as female patients, and the etiology was idiopathic in 91.1%, central nervous system (CNS) tumor at the hypothalamus-pituitary area in 1.7%, CNS tumor distant from the hypothalamus-pituitary area in 0.68%, other tumors in 0.91%, congenital CNS malformations in 0.83%, and other diseases in 1.1% with their specific characteristics. The latest average age, height standard deviation score (SDS), insulin-like growth factor-1 SDS, and proportion of severe GHD at GH treatment initiation were 8.8 years, -2.76, -1.42, and 19.5%, respectively. The proportions of breech delivery and asphyxia gradually decreased, whereas that of caesarean section gradually increased during the registration period with the latest values of 2.2%, 4.9%, and 14.0%, respectively (all analyses: p0.0001). In contrast, the proportion of idiopathic GHD with breech delivery seemed to reach the lowest level among those with a birth year before 2000. This study identified the characteristics and changes of patients with GHD over 20 years.

The identification of thyroid cancers among children after the Chernobyl nuclear power plant accident propelled concerns regarding long-term radiation effects on thyroid cancer in children affected by the Fukushima Daiichi nuclear power plant accident in Fukushima, Japan. Herein we consider the potential association between absorbed dose in the thyroid and the risk of developing thyroid cancer as detected by ultrasonography on 300 473 children and adolescents aged 0–18 years in Fukushima. The absorbed dose mentioned in the present study indicates the sum of that from external exposure and that from internally deposited radionuclides. We grouped participants according to estimated absorbed doses in each of 59 municipalities in Fukushima Prefecture, based on The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2013 report. The 59 municipalities were assigned to quartiles by dose. We limited our analyses to participants aged ≥6 years because only one case of thyroid cancer was observed in participants aged ≤5 years; 164 299 participants were included in the final analysis. Compared with the lowest dose quartile, the age- and sex-adjusted rate ratios (95% confidence intervals) for the low-middle, high-middle and highest quartiles were 2.00 (0.84–4.80), 1.34 (0.50–3.59) and 1.42 (0.55–3.67) for the 6–14-year-old groups and 1.99 (0.70–5.70), 0.54 (0.13–2.31) and 0.51 (0.12–2.15) for the >15-year-old group, respectively. No dose-dependent pattern emerged from the geographical distribution of absorbed doses by municipality, as estimated by UNSCEAR, and the detection of thyroid cancer among participants within 4–6 years after the accident. Ongoing surveillance might further clarify the effects of low-dose radiation exposure on thyroid cancer in Fukushima.

This study aimed to characterize the safety and effectiveness of GH treatments, in usual clinical practice, in children with short stature born small for gestational age (SGA). This was a multicenter, open-label, non-interventional study (NCT01110928) conducted at 150 sites in Japan (2009–2018). The primary objective was to assess the type and frequency of serious adverse drug reactions (SADRs) associated with long-term GH use. Overall, 452 naïve and 46 non-naïve (previously treated) children were enrolled. GH treatment was well‑tolerated, with SADRs occurring in 1.3% (6/452) and 0% (0/46) of naïve and non-naïve children, respectively. No new safety concerns or notable changes in glucose metabolism were identified during long-term treatment. Altogether, 57 children (32 naïve and 25 non-naïve) reached near adult height (NAH). In naïve and non-naïve children, mean ± standard deviation (SD) height standard deviation score (SDS) at NAH were –2.03 ± 0.77 and –1.53 ± 0.81, respectively, representing a change of +0.85 ± 0.72 and +1.24 ± 0.66 from baseline height SDS, respectively. Mean treatment duration to NAH was 4.29 (naïve) and 7.26 (non-naïve) yr. Thus, long-term GH treatment for short stature in children born SGA was confirmed to have a good safety profile and was effective for improving adult height.

This 4-year randomized, double-blind, multicenter trial (NCT01927861) investigated the long-term efficacy and safety of Norditropin® (NN-220; somatropin) in Japanese children with short stature due to Noonan syndrome. Pre-pubertal children with Noonan syndrome were randomized 1:1 to receive 0.033 mg/kg/day (n = 25, mean age 6.57 years) or 0.066 mg/kg/day (n = 26, mean age 6.06 years) GH. Height standard deviation score (SDS) change after 208 weeks from baseline was evaluated using an analysis of covariance model. Height SDS improved from -3.24 at baseline with a significantly greater increase (estimated mean [95% confidence interval]) with 0.066 vs. 0.033 mg/kg/day GH (1.84 [1.58; 2.10] vs. 0.85 [0.59; 1.12]; estimated mean difference 0.99 [0.62; 1.36]; p < 0.0001). The majority of treatment-emergent adverse events (TEAEs) were non-serious, mild and assessed as unlikely treatment-related. TEAE rates and frequencies of serious TEAEs were similar between groups. Three patients receiving 0.066 mg/kg/day were withdrawn; two due to TEAEs at days 1,041 and 1,289. Mean insulin-like growth factor-I SDS increased from -1.71 to -0.75 (0.033 mg/kg/day) and 0.57 (0.066 mg/kg/day) (statistically significant difference). In both groups, there were only minor glycosylated hemoglobin changes, similar oral glucose tolerance test insulin response increases and no clinically relevant changes in oral glucose tolerance test blood glucose, vital signs, electrocardiogram or transthoracic echocardiography. In conclusion, treatment with 0.033 and 0.066 mg/kg/day GH for 208 weeks improved height SDS in Japanese children with short stature due to Noonan syndrome with a significantly greater increase with 0.066 vs. 0.033 mg/kg/day GH and was well tolerated, with no new safety concerns.

Background and Purpose The Thyroid Ultrasound Examination (TUE) program is conducted as part of the Fukushima Health Management Survey. Following the established criteria, examinees are called in for a secondary confirmation examination, which may induce high anxiety related to a thyroid cancer for both the examinees and their families. Therefore, Fukushima Medical University created the Thyroid Support Team to reduce anxiety. The purpose of this study is to analyze the psychosocial support for examinees and their families through two types of records, and to clarify the current issues and determine future directions of support. Materials and methods We analyzed 223 records of support for the first visit of examinees who attended the secondary confirmatory examination, conducted at Fukushima Medical University from September 2018 to March 2019. Results During the first visit, frequent topics and questions brought up by the examinees and their families were about the “Thyroid Ultrasound Examination (TUE) program” and “Examination findings”. The Thyroid Support Team members assisted them by “Responding to questions”, “Confirming the doctor’s explanation” and “Providing information”. The percentage of people with high anxiety decreased in both examinees and their family members after the examination. The level of anxiety was lower among those who had already taken the secondary confirmatory examination. Family members’ anxiety was significantly higher than that of the examinees, and anxiety levels were highly correlated between examinees and their families. Conclusion The psychosocial support for examinees and their families was important in reducing their anxiety. Currently there are changes in social conditions and various opinions concerning the TUE. Thus, careful explanation and the need for decision-making supports for the examinees and their families increased. Also, we should take into account the aging of the examinees and expanding the available psychosocial support.

The incidence of thyroid carcinoma has been increasing worldwide. This is interpreted as an increase in the incidental detection of papillary thyroid microcarcinomas (PTMCs). However, mortality has not changed, suggesting overdiagnosis and overtreatment. Prospective clinical trials of active surveillance for low-risk PTMC (T1aN0M0) have been conducted in two Japanese institutions since the 1990s. Based on the favorable outcomes of these trials, active surveillance has been gradually adopted worldwide. A task force on the management of PTMC in adults organized by the Japan Thyroid Association therefore conducted a systematic review and has produced the present position paper based on the scientific evidence concerning active surveillance. This paper indicates evidence for the increased incidence of PTMC, favorable surgical outcomes for low-risk PTMC, recommended criteria for diagnosis using fine needle aspiration cytology, and evaluation of lymph node metastasis (LNM), extrathyroidal extension (ETE) and distant metastasis. Active surveillance has also been reported with a low incidence of disease progression and no subsequent recurrence or adverse events on survival if conversion surgery was performed at a slightly advanced stage. Active surveillance is a safe and valid strategy for PTMC, because it might preserve physical quality of life and reduce 10-year medical costs. However, some points should be noted when performing active surveillance. Immediate surgery is needed for PTMC showing high-risk features, such as clinical LNM, ETE or distant metastasis. Active surveillance should be performed under an appropriate medical team and should be continued for life.

The Fukushima Daiichi Nuclear Power Plant accident occurred on March 11 2011, following the Great East Japan Earthquake and tsunami. Radioactive materials, including I-131, were released into the environment after the accident. Shortly after, the prefectural government initiated the Fukushima Health Management Survey for monitoring the long-term health conditions of the residents of Fukushima Prefecture. In the survey, thyroid ultrasonography was scheduled for all people aged 18 years or younger who were living in Fukushima Prefecture at the time of disaster. The total number of examinees was approximately 370,000 in the Preliminary Baseline Survey (PBLS), and 380,000 in the first Full-scale Survey (FSS). First, thyroid ultrasonography was performed as the Primary Examination. When a thyroid nodule that meets the fine needle aspiration cytology (FNAC) guideline is detected, thyroid FNAC is performed. By the end of June 2017, the cytological specimens of 187 examinees had been interpreted as Malignant or Suspicious for Malignancy (SFM). In this article, the cytological results of whole categories are presented using the criteria of The Bethesda System for Reporting Thyroid Cytopathology. The total numbers of examinees with SFM or Malignant in PBLS and at the first FSS were 106 (62.0%) and 71 (38.0%), respectively. The data of the cytological results of SFM and Malignant were already reported. However, this is the first report of cytological data from categories other than SFM and Malignant. The results of the current study will contribute to future research into the thyroid conditions of children and adolescents.

Background Thyrotoxicosis is common disorder among endocrine dysfunctions. It is not rare that the free thyroid hormone level exceeds the measurement range of immunoassay. Such extreme high concentration of free thyroid hormone is generally considered to be impossible to measure correctly because of changes in the balance between free hormones and binding proteins by dilution of serum. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), however, higher concentrations are able to be determined. Case presentation We present a case of a 21-year-old female with congenital hypothyroidism who had taken a total of 5 mg levothyroxine over three consecutive days following discontinuance of the medication for a month. Immunoassay performed 3 hours after the last ingestion showed that the patient’s free thyroxine (FT4) was over 100 pmol/L and her free triiodothyronine (FT3) was 24.5 pmol/L. With a temporary cessation of levothyroxine, the patient was kept for observation without any other medication. Two days after the last ingestion, FT4 was still over 100 pmol/L and FT3 was increased to 28.8 pmol/L. After an additional 4 days, both FT4 and FT3 levels decreased. Through this period, no thyrotoxic symptom or physical sign had appeared. We also measured FT4 and FT3 levels in her cryopreserved serum by ultrafiltration LC-MS/MS. Her FT4 level measured by ultrafiltration LC-MS/MS on the visiting day and 2 days later were 160.0 and 135.5 pmol/L, respectively, indicating that the toxic dose of levothyroxine was partly changed to T3 during the 2 days. The FT3/FT4 ratios were revealed to be low, accounting for the patient’s benign clinical course despite temporal toxic exposure to levothyroxine. It is implied that prior discontinuation of supplementary levothyroxine increases potential vacant binding sites for thyroid hormone as a buffer to prevent toxic T3 effect. Conclusion It was helpful to clarify the time dependent changes in free thyroid hormone levels by ultrafiltration LC-MS/MS in discussing the clinical course in this case. Though mass spectrometry has a disadvantage in speed for routine laboratory use, its accurate measurement, particularly of levels exceeding the measurable range of the immunoassay, provides valuable information for more appropriate management of extreme thyrotoxicosis.

Cryptorchidism (undescended testes) is among the most common congenital diseases in male children. Although many factors have been linked to the incidence of cryptorchidism, and testicular androgen plays a key role in its pathogenesis, the cause remains unknown in most cases. Recently, a Japanese group published a speculative paper entitled, “Nationwide increase in cryptorchidism after the Fukushima nuclear accident.” Although the authors implicated radionuclides emitted from the Fukushima accident as contributing to an increased incidence of cryptorchidism, they failed to establish biological plausibility for their hypothesis, and glossed over an abundance of evidence and expert opinion to the contrary. We assessed the adequacy of their study in terms of design setting, data analysis, and its conclusion from various perspectives. Numerous factors must be considered, including genetic, environmental, maternal/fetal, and social factors associated with the reporting of cryptorchidism. Other investigators have established that the doses of external and internal radiation exposure in both Fukushima prefecture and the whole of Japan after the accident are too low to affect testicular descent during fetal periods; thus, a putative association can be theoretically and empirically rejected. Alternative explanations exist for the reported estimates of increased cryptorchidism surgeries in the years following Japan’s 2011 earthquake, tsunami, and nuclear crisis. Data from independent sources cast doubt on the extent to which cryptorchidism increased, if at all. In any case, evidence that radionuclides from the Fukushima Daiichi Nuclear Power Plant could cause cryptorchidism is lacking.

This 4-year randomized, double-blind, multicenter trial (NCT01927861) investigated the long-term efficacy and safety of Norditropin

ObjectivesHealthy-weight children tend to gain weight during winter but lose weight during summer. However, overweight elementary school children have shown accelerated summertime weight gain. Whether this seasonal growth variation occurs during preschool period is of substantial interest.MethodsData were derived from a nationwide retrospective cohort of nursery school children. Eight consecutive sets of longitudinal measurements on height and weight were obtained from 15 259 preschool children. Thereafter, growth in height, weight and body mass index (BMI) over a period of 6 months was calculated. Summertime growth was defined as that from April to October, whereas wintertime growth was defined as that from October to April of the following year. Longitudinal growth seasonality was analysed by classifying children according to their BMI status at the age of elementary school entry.ResultsAccelerated summertime weight and BMI gain were observed among children with obesity. This distinctive growth seasonality was detected from around age 2. Children having this growth seasonality at approximately 2 years of age tended to be obese at the age of elementary school entry (OR: 3.7; 95% CI: 2.9 to 4.6; pConclusionEarly excessive growth with distinct seasonality was observed in preschool obese children. These findings suggest that individuals involved in child healthcare should pay closer attention to early excessive growth with distinct seasonality in preschool obesity.

The efficacy and safety of recombinant human GH (rhGH) treatment were assessed in Japanese children with small-for-gestational-age short stature. A total of 88 patients were enrolled in the comparative and extension studies. At the end of the comparative study (24 mo), the mean height SD score for chronological age had significantly increased in the 0.23 mg/kg/wk and 0.47 mg/kg/wk groups with increments of 0.84 ± 0.42 and 1.50 ± 0.44 SD, respectively. In the extension study, the dose could be increased based on the pre-defined growth criteria. Increments in height SD scores over the 24 to 36 mo period at doses of 0.23 mg/kg/wk, 0.23 to 0.47 mg/kg/wk, and 0.47 mg/kg/wk were 0.25 ± 0.28, 0.46 ± 0.21, and 0.28 ± 0.16 SD, respectively. The growth effect increased following dose escalation even in the low responders in the initial 2-yr treatment at 0.23 mg/kg/wk, indicating the effectiveness of dose escalation in accordance with the Japanese guidelines. rhGH at 0.47 mg/kg/wk provided a greater degree of growth promotion after 24 mo. The safety profile appeared to be tolerable and was similar in all groups. Considering the increased insulin resistance, the recommendations of the regulatory authorities should be followed to minimize the risks of rhGH treatment.

This randomized double-blind multicenter trial (NCT01927861) evaluated the growth-promoting effect and safety of Norditropin® (NN220; somatropin) in Japanese children with short stature due to Noonan syndrome. Prepubertal children aged 3

Longitudinal growth data of children were analyzed to clarify the relationship between the timing of body mass index (BMI) rebound and obesity risk in later ages. Of 54 558 children born between April 2004 and March 2005 and longitudinally measured in April and October every year in the preschool period, 15 255 children were analyzed wherein no longitudinal measurement is missing after 1 year of age. BMI rebound age was determined as the age with smallest BMI value across longitudinal individual data after 1 year of age. Rebound age was compared between overweight and non-overweight groups. The subjects were divided into groups based on the timing of rebound. The sex- and age-adjusted mean of the BMI, height and weight s.d. scores for age group, along with 6 months weight and height gain, were compared among groups using analysis of covariance. Among those who were overweight at 66–71 months of age, BMI rebound age obtained at approximately 3 years of age was compared with the non-overweight group, whose BMI rebound age was utmost 66 months or later (P

Background Data for earthquake-related alterations in physique among young children in developed countries is lacking. The Great East Japan Earthquake caused severe damage in Iwate, Miyagi, and Fukushima Prefectures in northeastern Japan. Methods We retrospectively obtained anthropometric measurements in nursery school from 40,046 (cohort 1, historical control) and 53,492 (cohort 2) children aged 3.5–4.5 years without overweight in October 2008, and in October 2010, respectively. At the time of the earthquake in March, 2011, children in cohort 1 had already graduated from nursery school; however, children in cohort 2 were still enrolled in nursery school at this time. We compared the onset of overweight at 1 year after the baseline between children enrolled in their school located in one of the three target prefectures versus those in other prefectures using a logistic regression model, with adjustment for sex, age, history of disease, and obesity index at baseline. Overweight was defined as an obesity index of >+15%, which was calculated as (weight minus sex- and height-specific standard weight)/sex- and height-specific standard weight. Results The odds ratio (OR) for the onset of overweight in the three target prefectures was significant in cohort 2 (OR 1.25; 95% confidence interval [CI], 1.01–1.55) but not in cohort 1. When the two cohort were pooled (n = 93,538), the OR of the interaction term for school location × cohort was significant (OR 1.56; 95% CI, 1.09–2.23). Conclusions Incident overweight in young children was significantly more common in the three prefectures affected by the Great East Japan Earthquake than in other prefectures after the disaster., Highlights • We obtained anthropometric data from 93,538 children aged 3.5–4.5 years. • Anthropometric data were measured before and after the Great East Japan Earthquake. • We compared the data in Iwate, Miyagi, and Fukushima vs. the other prefectures. • Incident overweight was higher in the three prefectures than the other prefectures.

Although existing guidelines recommend long-term follow-up of childhood cancer survivors (CCSs), their fertility has not been fully investigated in Japan. To address this issue, we organized a working panel consisting of medical specialists in foundation hospitals. We conducted questionnaire surveys targeting pediatric endocrinologists regarding reproduction in pediatric and adolescent cancer patients in collaboration with the CCS committee of the Japanese Society for Pediatric Endocrinology (JSPE). The first questionnaire was sent to 178 directors or councilors of the JSPE, and the second was sent to those who had provided answers on their experience with childbirth or fertility preservation. A total of 151 responses (84.8%) were obtained in the first survey. In the second survey, the response rate was 100% (39 respondents). There were 27 answers describing experiences with childbirth (16 from partners of male CCSs, 22 from female CCSs). A few cases of premature birth and low birth weight were reported. There were 25 answers describing experiences with fertility preservation; 21 were from male and 17 from female CCSs. It was mainly physicians who recommended fertility preservation. This nationwide questionnaire survey revealed that a limited number of Japanese pediatric endocrinologists had experience with childbirth and fertility preservation in CCSs. A further long-term follow-up study of their fertility is needed.

Background To investigate the impact of the Great East Japan Earthquake on preschool children's physical growth in the disaster-affected areas, the three medical universities in Iwate, Miyagi, and Fukushima Prefectures conducted a health examination survey on early childhood physical growth. Methods The survey was conducted over a 3-year period to acquire data on children who were born in different years. Our targets were as follows: 1) children who were born between March 1, 2007 and August 31, 2007 and experienced the disaster at 43–48 months of age, 2) children who were born between March 1, 2009 and August 31, 2009 and experienced the disaster at 19–24 months of age, and 3) children who were born between June 1, 2010 and April 30, 2011 and were under 10 months of age or not born yet when the disaster occurred. We collected their health examination data from local governments in Iwate, Miyagi, and Fukushima Prefectures. We also collected data from Aomori, Akita, and Yamagata Prefectures to use as a control group. The survey items included birth information, anthropometric measurements, and methods of nutrition during infancy. Results Eighty municipalities from Iwate, Miyagi, and Fukushima Prefectures and 21 from the control prefectures participated in the survey. As a result, we established three retrospective cohorts consisting of 13,886, 15,474, and 32,202 preschool children. Conclusions The large datasets acquired for the present survey will provide valuable epidemiological evidence that should shed light on preschool children's physical growth in relation to the disaster., Highlights • We conducted surveys on physical growth among children in relation to the disaster. • We acquired one of the largest longitudinal datasets of Japanese preschool children. • We will provide epidemiological evidence on children's health after the disaster.

The evacuation and disruption in housing caused by the 2011 Great East Japan Earthquake and following nuclear radiation may have influenced child health in many respects. However, studies regarding longitudinal childhood growth are limited. Therefore, in this study we aimed to explore the influence of the earthquake on longitudinal changes in body mass index in preschool children.Participants were children from nursery schools who cooperated with the study in the Iwate, Miyagi and Fukushima prefectures. The exposed group consisted of children who experienced the earthquake during their preschool-age period (4-5 years old). The historical control group included children who were born 2 years earlier than the exposed children in the same prefectures. Trajectories regarding body mass index and prevalence of overweight/obesity were compared between the two groups using multilevel analysis. Differences in the changes in BMI between before and after the earthquake, and proportion of overweight/obesity was compared between the two groups. We also conducted subgroup analysis by defining children with specific personal disaster experiences within the exposed group.A total of 9722 children were included in the study. Children in the exposed group had higher body mass indices and a higher proportion of overweight after the earthquake than the control group. These differences were more obvious when confined to exposed children with specific personal disaster experiences.Children's growth and development-related health issues such as increased BMI after natural disasters should evoke great attention.