Database of Families with Twins and Higher Order Multiples in Japanese Twins Mothers Clubs.

It is desirable for twin researchers to be aware of the needs and concerns of families of multiples and provide participants with appropriate and useful feedback and advice based on scientific evidence. Our most recent database on families with twins throughout Japan is based on a questionnaire survey conducted in 2016. Mailed questionnaires, consisting of over 500 items, were used to collect the basic data. The response rate was 38% (566/1478). This is part of a nationwide study designed to assess the long-term effect of perinatal conditions on mothers of multiples. Its aim was to study the growth and development of multiples in childhood, and for the creation of a multifetal mother and child health handbook, and to conduct a genetic epidemiologic study to test the developmental origin of health and disease hypothesis. One of the ultimate aims of this research was to provide evidence-based information on parenting of multiples for families with multiples.

Twin Database of the Secondary School Attached to the Faculty of Education of the University of Tokyo.

This article profiles the historical twin databases of the secondary education school attached to the Faculty of Education at the University of Tokyo. The school was established in 1948. Every year, about 50 pairs of twins of all sex and zygosity combinations, aged 11-12 years, take an examination, and about 10-20 pairs are admitted based on the results. Three datasets exist: one for applicants (11-12 years old), one for junior and senior high school students (12-18 years old) and one for graduates (18-85 years old). Linking the records from these three databases should facilitate several important research projects, for example, life course genetic epidemiologic studies and the verification of the so-called developmental origins of health and disease hypothesis.

Twin's Birth-Order Differences in Height and Body Mass Index From Birth to Old Age: A Pooled Study of 26 Twin Cohorts Participating in the CODATwins Project.

We analyzed birth order differences in means and variances of height and body mass index (BMI) in monozygotic (MZ) and dizygotic (DZ) twins from infancy to old age. The data were derived from the international CODATwins database. The total number of height and BMI measures from 0.5 to 79.5 years of age was 397,466. As expected, first-born twins had greater birth weight than second-born twins. With respect to height, first-born twins were slightly taller than second-born twins in childhood. After adjusting the results for birth weight, the birth order differences decreased and were no longer statistically significant. First-born twins had greater BMI than the second-born twins over childhood and adolescence. After adjusting the results for birth weight, birth order was still associated with BMI until 12 years of age. No interaction effect between birth order and zygosity was found. Only limited evidence was found that birth order influenced variances of height or BMI. The results were similar among boys and girls and also in MZ and DZ twins. Overall, the differences in height and BMI between first- and second-born twins were modest even in early childhood, while adjustment for birth weight reduced the birth order differences but did not remove them for BMI.

Birth defects after assisted reproductive technology according to the method of treatment in Japan: nationwide data between 2004 and 2012.

OBJECTIVES: The purpose of the present study was to analyze birth defects (congenital anomalies) after assisted reproductive technology (ART) according to the method of treatment, namely in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI) and frozen-thawed embryo transfer (FET). METHODS: Individual lists of all ART pregnancies resulting in birth defects from birth year 2004 to 2012 presented in the annual reports by the Japan Society of Obstetrics and Gynecology were used as the initial sources of information. Relative risks (RRs) with the corresponding 95 % confidence intervals (CIs) were calculated with IVF as the reference group when calculating RR of ICSI for IVF, and with FET as the reference group when calculating the RR of fresh embryo transfer for FET. RESULTS: In total, 2725 stillbirths or live births with birth defects were analyzed. The prevalence of birth defects was slightly yet significantly higher in ICSI compared with IVF throughout the study period (RR = 1.15, 95 % CI 1.02-1.29) and in the 2004-2006 period (RR = 1.26, 95 % CI 1.00-1.58). The prevalence of birth defects was significantly higher for fresh embryo transfer compared with FET in the 2004-2006 period (RR = 1.39, 95 % CI 1.12-1.72). The prevalence of birth defects in multiple births was significantly lower in fresh embryo transfer compared with FET (RR = 0.70, 95 % CI 0.55-0.90, live births of 2007-2012). CONCLUSIONS: The present descriptive epidemiological study suggests that the impacts of different ART methods on birth defects might differ.

Tai chi improves cognitive and physical function in the elderly: a randomized controlled trial.

[Purpose] To investigate the effect of Tai Chi on cognitive and physical function in the elderly. [Subjects and Methods] A randomized trial design was used. A total 150 subjects were enrolled and were divided into Tai Chi and control groups. Subjects in the Tai Chi group participated Tai Chi for 6 months, and subjects in the control group participated in other non-athletic activities. [Results] There were no differences between the groups in the one leg standing time with eyes open, left grip strength, or the Frontal Assessment Battery at bedside after 3 and 6 months of intervention. The Mini-Mental State Examination scores after 3 and 6 months were higher in the Tai Chi group than in the control group. The right grip strength after 3 months increased more in the Tai Chi group than in the control group. Both the 5-m high walking speed and 10-m normal walking speed were significantly lower after 3 and 6 months of Tai Chi practice. [Conclusion] These results suggest that regular Tai Chi practice may improve cognitive and physical function in the elderly.

Concordance rates of birth defects after assisted reproductive technology among 17 258 Japanese twin pregnancies: a nationwide survey, 2004-2009.

BACKGROUND: Most twins after assisted reproductive technology (ART) are dizygotic. Analysis of dizygotic twin pairs is useful in assessing familial aggregation in the development of birth defects. METHODS: Using nationwide post-ART data from the Japan Society of Obstetrics and Gynecology, recurrence risk ratios (RRRs)-defined as probandwise concordance rates of birth defects in twins divided by the prevalence of birth defects in the general population-were calculated as indicators of familial aggregation. Birth defects were then reclassified according to the ICD-10 categories corresponding to codes Q00-Q99. From 2004 to 2009, there were 17 258 twin pregnancies. RESULTS: At least 1 birth defect was noted in 236 twin pairs: 11 concordant and 225 discordant pairs. Regarding major organ systems, high probandwise concordance rates were observed for congenital malformations of eye, ear, face, and neck (11.8%), cleft lip and cleft palate (10.5%), congenital malformations of the nervous system (9.8%), and other congenital malformations of the digestive system (9.5%). High RRRs were observed for congenital malformations of eye, ear, face, and neck (RRR = 233), specifically other congenital malformations of the ear (RRR = 449); congenital malformations of the great arteries (RRR = 235), specifically those of the patent ductus arteriosus (RRR = 530); and for cleft lip and cleft palate (RRR = 208), specifically cleft palate with cleft lip (RRR = 609). The probandwise concordance rate of any birth defect (8.9%) was nearly identical to the approximated recurrence risk of sib-pairs (8.8%), which assumed multifactorial inheritance. CONCLUSIONS: The present findings suggest that familial aggregation is a factor in some birth defects.

Twin database of the secondary school attached to the Faculty of Education of the University of Tokyo: lifecourse database of twins.

This article profiles the historical twin databases of the secondary education school attached to the Faculty of Education at the University of Tokyo. The school was established in 1948. Every year, about 50 pairs of twins of all sex and zygosity combinations and aged 11-12 years take an examination, and about 10-20 pairs are admitted based on the results. Three data sets exist: one for applicants (11-12 years), one for junior and senior high school students (12-18 years), and one for graduates (18-79 years). Record linkage of these three databases should facilitate several important research projects; for example, the lifecourse genetic epidemiologic studies and verification of so-called developmental origin of health and disease hypothesis.

Japanese database of families with twins and higher-order multiples.

To gain widespread participation, epidemiologic studies of twins from pregnancy through the childhood period are expected to reflect the needs and concerns of families and provide participants with appropriate and useful feedback based on scientific evidence. Our most recent database on families with twins throughout Japan is based on a questionnaire survey conducted from January 2010 to August 2011. Mailed or hand-delivered questionnaires, consisting of over 550 items were used to collect the basic data. The response rate was 40% (956/2,401). This is part of a nation-wide study designed to assess the long-term effect of perinatal conditions on mothers of multiples. Its aim was to study the growth and development of multiples in childhood, and to conduct a genetic epidemiologic study to test the developmental origin of health and disease hypothesis. One of the ultimate aims of this research was to provide evidence-based information on parenting multiples from pregnancy through childhood to families with multiples.

Characteristics of fatal child maltreatment associated with multiple births in Japan.

The purpose of the present study was to clarify the characteristics of fatal child maltreatment in families with multiple births in Japan. An exhaustive information search was performed to find multiple-birth cases between July 2003 and March 2011. There were 437 cases of fatal maltreatment of children aged 0-17 years during this period, including 14 involving multiple-birth children. A keyword search was performed to create a full profile for each multiple-birth case. The 14 multiple-birth victims were twins from 13 families. No significant difference between twins and singletons with fatal maltreatment was observed for most characteristics. However, in the case of twins, 0-month victims were rare, and the number of children per family was larger. One twin died from shaken baby syndrome. The victim's siblings were also maltreated in six out of 12 relevant cases, including all six co-twins. Premature birth, having a disabled co-twin, delay of growth or development, and parental disfavor tended to be factors of maltreatment when only one twin was maltreated. Four families were given suspended sentences in total, including three mothers who acted as solitary murderers (43% = 3/7). In conclusion, recent Japanese nationwide data suggests that the non-specific overburden of child rearing might be one possible reason for higher frequency of child maltreatment for multiples compared with singletons, and parental comparisons between two twins might be another. The penal sentences for fatal child maltreatment might be more lenient for perpetrators of this crime against twins than against singletons.

Two cohort and three independent anonymous twin projects at the Keio Twin Research Center (KoTReC).

The Keio Twin Research Center has conducted two longitudinal twin cohort projects and has collected three independent and anonymous twin data sets for studies of phenotypes related to psychological, socio-economic, and mental health factors. The Keio Twin Study has examined adolescent and adult cohorts, with a total of over 2,400 pairs of twins and their parents. DNA samples are available for approximately 600 of these twin pairs. The Tokyo Twin Cohort Project has followed a total of 1,600 twin pairs from infancy to early childhood. The large-scale cross-sectional twin study (CROSS) has collected data from over 4,000 twin pairs, from 3 to 26 years of age, and from two high school twin cohorts containing a total of 1,000 pairs of twins. These data sets of anonymous twin studies have mainly targeted academic performance, attitude, and social environment. The present article introduces the research designs and major findings of our center, such as genetic structures of cognitive abilities, personality traits, and academic performances, developmental effects of genes and environment on attitude, socio-cognitive ability and parenting, genes x environment interaction on attitude and conduct problem, and statistical methodological challenges and so on. We discuss the challenges in conducting twin research in Japan.

Fatal child maltreatment associated with multiple births in Japan: nationwide data between July 2003 and March 2011.

OBJECTIVES: The purpose of the present study is to clarify the impact of multiple births in fatal child maltreatment (child death due to maltreatment). METHODS: The national annual reports on fatal child maltreatment, which contain all cases from July 2003 to March 2011, published by the Ministry of Health, Labor and Welfare of Japan, were used as the initial sources of information. Parent-child murder-suicide cases were excluded from the analyses. Multiple births, teenage pregnancy and low-birthweight were regarded as the exposed groups. The relative risks (RRs) and their 95 % confidence intervals (CIs) were estimated using the data from the above reports and vital statistics. These analyses were performed both including and excluding missing values. RESULTS: Among 437 fatal child maltreatment cases, 14 multiple births from 13 families were identified. The RRs of multiple births per individual were 1.8 (95 % CI 1.0-3.0) when including missing values and 2.7 (95 % CI 1.5-4.8) when excluding missing values. The RRs of multiple births per family were 3.6 (95 % CI 2.1-6.2) when including missing values and 4.9 (95 % CI 2.7-9.0) when excluding missing values. The RR tended to be much lower than the RR of teenage pregnancy (RR 12.9 or 22.2), but slightly higher than the RR of low-birthweight (RR 1.4 or 2.9). CONCLUSIONS: Families with multiple births had elevated risk for fatal child maltreatment both per individual and per family unit. Health providers should be aware that multiple pregnancies/births may place significant stress on families and should provide appropriate support and intervention.

Effect of maternal age and fertility treatment on the increase in multiple births in Japan: vital statistics, 1974-2009.

BACKGROUND: The present study used vital-statistics data to estimate the effect of maternal age and fertility treatment on the number and rate of multiple live births in Japan from 1974 through 2009. METHODS: Japanese vital statistics published by the Ministry of Health, Labour and Welfare from 1974 to 2009 were gathered and reanalyzed with regard to maternal age class and plurality of live births. The numbers of spontaneous and iatrogenic multiple births during 1977-2009 were estimated, with the assumption that spontaneous multiple-birth rates according to maternal age class would be constant and equal to those of baseline values, ie, the means between 1974 and 1976. RESULTS: During the 25-year period, multiple-birth rates according to maternal age class increased after the late 1980s. This tendency was obvious in women aged 35 to 39 years. The estimated numbers of iatrogenic multiple births remained nearly constant in women aged 20 to 24 years and greatly increased in women aged 30 to 34 and 35 to 39 years. The rate (per 1000 live births) of iatrogenic multiple births gradually increased from 0.7 (1977) to 1.3 (1986), then rapidly and markedly increased from 1.3 (1986) to 11.4 (2005), and finally decreased to 8.1 (2009). The estimated maximum percentage of iatrogenic multiple births was 50.0%, in 2004 and 2005. CONCLUSIONS: The rapid increases in Japan in the number and rate of multiples born to women older than 30 years are likely due to iatrogenic rather than spontaneous multiple births.

Estimation of the contribution of assisted and non-assisted reproductive technology fertility treatments to multiple births during the past 30 years in Japan: 1979-2008.

The effect of assisted reproductive technology (ART) and non-ART ovulation stimulation fertility treatment on the number and rate of multiple live births from 1979-2008 in Japan was estimated using two independent data sources, ART statistics and vital statistics. Japanese ART statistics presented by the Japan Society of Obstetrics and Gynecology between 1989 and 2008 were gathered and reanalyzed. The number and rates of ART between 1984 and 1988 were interpolated using an approximation formula, using the values from 1983, when the first ART baby was born in Japan, and the 1989-1992 values. The number of ART multiples between 1979-1982 was set as equal to zero. The minimum (or maximum) number of non-ART iatrogenic multiple births was estimated by subtracting the maximum (or minimum) ART multiples from the total iatrogenic multiples, which was estimated by vital statistics assuming that spontaneous multiple-birth rates according to maternal age class would be constant. There was an overall increase in the non-ART multiple births during the 30-year period, whereas ART multiples tended to increase from 1983 to 2005, and then rapidly decreased thereafter. The number or percentage of ART multiples was almost consistently lower than that of non-ART multiples. The percentage of non-ART multiples (33%) among the total multiples was estimated to be about three times more than the ART multiples (11-12%) in 2008. Given the medical and social impact of multiple births, it is imperative to construct a hospital-based monitoring system for fertility treatments, specially non-ART fertility treatments and multiple births.

Estimation of the contribution of assisted and non-assisted reproductive technology fertility treatments to multiple births during the past 30 years in Japan: 1979-2008.

The effect of assisted reproductive technology (ART) and non-ART ovulation stimulation fertility treatment on the number and rate of multiple live births from 1979-2008 in Japan was estimated using two independent data sources, ART statistics and vital statistics. Japanese ART statistics presented by the Japan Society of Obstetrics and Gynecology between 1989 and 2008 were gathered and reanalyzed. The number and rates of ART between 1984 and 1988 were interpolated using an approximation formula, using the values from 1983, when the first ART baby was born in Japan, and the 1989-1992 values. The number of ART multiples between 1979-1982 was set as equal to zero. The minimum (or maximum) number of non-ART iatrogenic multiple births was estimated by subtracting the maximum (or minimum) ART multiples from the total iatrogenic multiples, which was estimated by vital statistics assuming that spontaneous multiple-birth rates according to maternal age class would be constant. There was an overall increase in the non-ART multiple births during the 30-year period, whereas ART multiples tended to increase from 1983 to 2005, and then rapidly decreased thereafter. The number or percentage of ART multiples was almost consistently lower than that of non-ART multiples. The percentage of non-ART multiples (33%) among the total multiples was estimated to be about three times more than the ART multiples (11-12%) in 2008. Given the medical and social impact of multiple births, it is imperative to construct a hospital-based monitoring system for fertility treatments, specially non-ART fertility treatments and multiple births.

The effect of an increase in the rate of multiple births on low-birth-weight and preterm deliveries during 1975-2008.

BACKGROUND: Despite the rapid increase in the rate of multiple births due to the growth of reproductive medicine, there have been no epidemiologic studies of the secular trends in the impact of multiple births on the rates of low-birth-weight and preterm deliveries in Japan. METHODS: Japanese vital statistics for multiple live births were obtained from the Ministry of Health, Labour and Welfare and reanalyzed. With singletons as the reference group, an analysis was performed of secular trends in relative risk and population attributable risk percent of low-birth-weight (<2500 grams), very-low-birth-weight (<1500 grams), and extremely-low-birth-weight (<1000 grams) deliveries, using 1975-2008 vital statistics, and of preterm deliveries (ie, before 37, 32, and 28 weeks), using 1979-2008 vital statistics. RESULTS: The rate of multiple births doubled during the past 2 decades, and about 2% of all neonates are now multiples. The population attributable risk percent tended to increase during the same period for all variables, and was approximately 20% in 2008. CONCLUSIONS: The public health impact of the rapid increase in multiple births remains high in Japan.

Birth size and gestational age in opposite-sex twins as compared to same-sex twins: An individual-based pooled analysis of 21 cohorts.

It is well established that boys are born heavier and longer than girls, but it remains unclear whether birth size in twins is affected by the sex of their co-twin. We conducted an individual-based pooled analysis of 21 twin cohorts in 15 countries derived from the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins), including 67,850 dizygotic twin individuals. Linear regression analyses showed that boys having a co-twin sister were, on average, 31 g (95% CI 18 to 45) heavier and 0.16 cm (95% CI 0.045 to 0.274) longer than those with a co-twin brother. In girls, birth size was not associated (5 g birth weight; 95% CI -8 to -18 and -0.089 cm birth length; 95% CI -0.202 to 0.025) with the sex of the co-twin. Gestational age was slightly shorter in boy-boy pairs than in boy-girl and girl-girl pairs. When birth size was standardized by gestational age, the magnitude of the associations was attenuated in boys, particularly for birth weight. In conclusion, boys with a co-twin sister are heavier and longer at birth than those with a co-twin brother. However, these differences are modest and partly explained by a longer gestation in the presence of a co-twin sister.

Associations between birth size and later height from infancy through adulthood: An individual based pooled analysis of 28 twin cohorts participating in the CODATwins project.

BACKGROUND: There is evidence that birth size is positively associated with height in later life, but it remains unclear whether this is explained by genetic factors or the intrauterine environment. AIM: To analyze the associations of birth weight, length and ponderal index with height from infancy through adulthood within mono- and dizygotic twin pairs, which provides insights into the role of genetic and environmental individual-specific factors. METHODS: This study is based on the data from 28 twin cohorts in 17 countries. The pooled data included 41,852 complete twin pairs (55% monozygotic and 45% same-sex dizygotic) with information on birth weight and a total of 112,409 paired height measurements at ages ranging from 1 to 69 years. Birth length was available for 19,881 complete twin pairs, with a total of 72,692 paired height measurements. The association between birth size and later height was analyzed at both the individual and within-pair level by linear regression analyses. RESULTS: Within twin pairs, regression coefficients showed that a 1-kg increase in birth weight and a 1-cm increase in birth length were associated with 1.14-4.25 cm and 0.18-0.90 cm taller height, respectively. The magnitude of the associations was generally greater within dizygotic than within monozygotic twin pairs, and this difference between zygosities was more pronounced for birth length. CONCLUSION: Both genetic and individual-specific environmental factors play a role in the association between birth size and later height from infancy to adulthood, with a larger role for genetics in the association with birth length than with birth weight.

[The current situation of older hospitalized patients in a cadre ward in Jilin, China].

OBJECTIVE: The proportion of elderly people and the nation's medical expenditures are rapidly increasing in China. The existence of cadre wards, where retired members of the cadre of the Communist Party of China are hospitalized and receive careful treatment, helps in providing care for the elderly. Elderly retired cadre patients are thought to be more frequently hospitalized and to stay in the hospital longer than elderly non-cadre patients on general hospital wards, and therefore might be expected make an important contribution to the increase in the nation's medical expenditures. However the current situation is not well characterized. The aim of this study was to provide a basis for possible solutions related to the cadre patient burden by determining the circumstances and background of these patients with long hospital stays and investigating their needs. METHODS: We analyzed the medical records of hospital discharges from a cadre ward from 2000 to 2004, and from general wards in 2004 at a large university-affiliated hospital in Jilin, China. Additionally, a questionnaire survey including an interview concerning needs was carried out in August 2005 for 100 elderly patients on the cadre ward (91% of the total patients on this ward) of the same hospital at that time. RESULTS: The mean length of hospital stays of patients on the cadre ward decreased by half during the study period, but remained longer than that of patients on general hospital wards. Regression analysis showed that of all the variables measured, the type of ward (cadre vs. general) was the most influential on the mean length of hospital stay. Moreover, patients who were hospitalized more often, males and older individuals showed longer hospital stays. The questionnaire survey showed that there are many patients who could be discharged from the hospital based on their health condition but are not discharged because outside care or welfare services are insufficient, or because there is little information available on social resources. CONCLUSIONS: Although medical policy, by which elderly retired cadre patients receive careful treatment, may contribute to the longer length of the hospital stay of the patients on the cadre ward, it was thought to be important to construct appropriate discharge plans and a support system after discharge to the community. The results provide important information for solution of medical problems related to elderly retired cadre patients in China.

Association between birthweight and later body mass index: an individual-based pooled analysis of 27 twin cohorts participating in the CODATwins project.

Background: There is evidence that birthweight is positively associated with body mass index (BMI) in later life, but it remains unclear whether this is explained by genetic factors or the intrauterine environment. We analysed the association between birthweight and BMI from infancy to adulthood within twin pairs, which provides insights into the role of genetic and environmental individual-specific factors. Methods: This study is based on the data from 27 twin cohorts in 17 countries. The pooled data included 78 642 twin individuals (20 635 monozygotic and 18 686 same-sex dizygotic twin pairs) with information on birthweight and a total of 214 930 BMI measurements at ages ranging from 1 to 49 years. The association between birthweight and BMI was analysed at both the individual and within-pair levels using linear regression analyses. Results: At the individual level, a 1-kg increase in birthweight was linearly associated with up to 0.9 kg/m2 higher BMI (P < 0.001). Within twin pairs, regression coefficients were generally greater (up to 1.2 kg/m2 per kg birthweight, P < 0.001) than those from the individual-level analyses. Intra-pair associations between birthweight and later BMI were similar in both zygosity groups and sexes and were lower in adulthood. Conclusions: These findings indicate that environmental factors unique to each individual have an important role in the positive association between birthweight and later BMI, at least until young adulthood.

Population-based database of multiples in childhood of Ishikawa Prefecture, Japan.

A new type of population-based database of multiples in childhood at the prefecture level was initiated in 2004 in Ishikawa Prefecture, Japan. We conducted an exhaustive search for demographic information concerning families with multiples, family support provided by governmental and medical institutions by mailed questionnaire, and at the same time tried to organize a human network to support such families. This registry aims not only to aid research on human genetics and maternal and child health, but also to contribute to the development of welfare programs for families with multiples.