Sachiko Inoue

Bio: Sachiko Inoue is an academic researcher from Okayama Prefectural University. The author has contributed to research in topics: Birth weight & Breastfeeding. The author has an hindex of 14, co-authored 27 publications receiving 578 citations. Previous affiliations of Sachiko Inoue include Harvard University & Okayama University.

Long-term exposure to methylmercury and psychiatric symptoms in residents of Minamata, Japan

Abstract: Introduction: It is well-known that prenatal or postnatal exposure to methylmercury can produce neurological signs in adults and children, exemplified by a case of large-scale poisoning in Minamata, Japan, in the 1950s However, evidence regarding whether pre- or postnatal exposure to methylmercury causes psychiatric symptoms (eg, impairment of intelligence and mood and behavioral dysfunction) is still limited-excluding cases of fetal Minamata disease patients Methods: We evaluated the effects of pre- or postnatal exposure to methylmercury on psychiatric symptoms using data derived from a 1971 population-based survey in Minamata and neighboring communities We adopted residential areas as an exposure indicator and psychiatric symptoms as the outcome Then, we estimated the adjusted prevalence odds ratio (POR) and confidence interval (Cl) of psychiatric symptoms in relation to residential area Results: There were 904 participants in Minamata (high exposure area), 1700 in Goshonoura (middle exposure area), and 913 in Ariake (low exposure area) Compared to the Ariake area, participants in the Minamata area manifested psychiatric symptoms more frequently: PORs for impairment of intelligence and mood and behavioral dysfunction were 52 (95% Cl: 37-73) and 44 (95% Cl: 29-67), respectively Furthermore, participants with psychiatric symptoms in the Minamata area more frequently had neurological signs Peaks in prevalence of psychiatric symptoms occurred around age 20 and in older age adults in the area These findings did not change when we excluded those who had been officially certified as Minamata disease patients by that time Conclusions: The present study suggests a relationship between pre- or postnatal exposure to methylmercury and psychiatric symptoms among the general population in Minamata even after excluding officially certified patients

Breastfeeding and obesity among schoolchildren: a nationwide longitudinal survey in Japan

Abstract: Importance Although it is suggested that breastfeeding is protective against obesity in children, the evidence remains inconclusive because of possible residual confounding by socioeconomic status or children’s lifestyle factors. Most of the participants in the previous studies were children in Western developed countries, so studies in a different context are awaited. Objective To examine the associations of breastfeeding with overweight and obesity among schoolchildren in Japan, with adjustment for the potential confounders. Design Secondary data analyses of a nationwide longitudinal survey ongoing since 2001, with results collected from 2001 to 2009. Setting All over Japan. Participants A total of 43 367 singleton children who were born after 37 gestational weeks and had information on their feeding during infancy. Exposures Five mutually exclusive infant feeding practice categories. Main Outcomes and Measures Underweight, normal weight (referent group), overweight, and obesity at 7 and 8 years of age defined by using international cutoff points of body mass index by sex and age. Results In multinomial logistic regression models with adjustment for children’s factors (sex, television viewing time, and computer game playing time) and maternal factors (educational attainment, smoking status, and working status), exclusive breastfeeding at 6 to 7 months of age was associated with decreased risk of overweight and obesity compared with formula feeding. The adjusted odds ratios were 0.85 (95% CI, 0.69-1.05) and 0.55 (95% CI, 0.39-0.78) for overweight and obesity, respectively, at 7 years of age. Similar results were observed at 8 years of age. Conclusions and Relevance Breastfeeding is associated with decreased risk of overweight and obesity among schoolchildren in Japan. Therefore, it would be better to encourage breastfeeding even in developed countries.

Association of breast feeding with early childhood dental caries: Japanese population-based study

Abstract: Objectives We investigated the association between breastfeeding duration during the first half year of life and the risk of early childhood caries from the age of 30 to 66 months in Japan. Design Observational study of a longitudinal survey. Setting A secondary data analysis of the Japanese Longitudinal Survey of Babies in the 21st Century. Participants 43 383 infants at the age of 6 months. Outcome measures Early childhood caries—defined as a child9s visit to a dentist for treatment of dental caries during the past 12 months—was ascertained from the caregiver from the age of 30 months in the survey. We estimated the risk of dental caries each year according to duration of breast feeding using logistic regression analyses. We controlled for a set of biological factors (birth weight, sex, parity and maternal age at delivery) and socioeconomic factors (maternal educational attainment and smoking status, marital status at delivery, family income and region of birth and residence). Results We found that infants who had been breast fed for at least 6 or 7 months, both exclusively and partially, were at elevated risk of dental caries at the age of 30 months compared with those who had been exclusively formula fed. Adjusted ORs were 1.78 (95% CI, (1.45 to 2.17)) for the exclusively breastfed group and 1.39 (1.14 to 1.70) for the partially breastfed group. However, the associations became attenuated through the follow-up period and were no longer statistically significant beyond the age of 42 months for the partially breastfed group and beyond the age of 54 months for the exclusively breastfed group. Conclusions We found an association between breast feeding for at least 6 or 7 months and elevated risk of dental caries at age 30 months. However, the association became attenuated as children grew older.

Does Habitual Physical Activity Prevent Insomnia? A Cross-Sectional and Longitudinal Study of Elderly Japanese

Abstract: Few epidemiological studies have examined the potential protective effects of physical activity on insomnia. The authors thus evaluated the association between physical activity and insomnia in a large population-based study in Shizuoka, Japan. Individual data were obtained from participants in an ongoing cohort study. A total of 14,001 older residents who completed questionnaires were followed for 3 yr. Of these, 10,211 and 3,697 participants were eligible for the cross-sectional and longitudinal analyses, respectively. The authors obtained information about the frequency of physical activity and insomnia. Then, the adjusted odds ratios and 95% confidence intervals between physical activity and insomnia were estimated. Habitual physical activity was related to lower prevalence of insomnia. Frequent physical activity also reduced the incidence of insomnia, especially difficulty maintaining sleep. For elderly people with sufficient mobility and no preexisting disease, high-frequency physical activity (e.g., 5 or more days/wk) may help reduce insomnia.

Impact of maternal and paternal smoking on birth outcomes

Abstract: Background The adverse effects of maternal and paternal smoking on child health have been studied. However, few studies demonstrate the interaction effects of maternal/paternal smoking, and birth outcomes other than birth weight have not been evaluated. The present study examined individual effects of maternal/paternal smoking and their interactions on birth outcomes. Methods A follow-up hospital-based study from pregnancy to delivery was conducted from 1997 to 2010 with parents and newborn infants who delivered at a large hospital in Hamamatsu, Japan. The relationships between smoking and growth were evaluated with logistic regression. Results The individual effects of maternal smoking are related to low birth weight (LBW), short birth length and small head circumference. The individual effects of paternal smoking are related to short birth length and small head circumference. In the adjusted model, both parents' smoking showed clear associations with LBW (odds ratio [OR] = 1.64, 95% confidence interval [CI] 1.18-2.27) and short birth length (-1 standard deviation [SD] OR = 1.38, 95% CI 1.07-1.79; -2 SD OR = 2.75, 95% CI 1.84-4.10). Conclusions Maternal smoking was significantly associated with birth weight and length, but paternal smoking was not. However, if both parents smoked, the risk of shorter birth length increased.

Mercury as a Global Pollutant: Sources, Pathways, and Effects

Abstract: Mercury (Hg) is a global pollutant that affects human and ecosystem health. We synthesize understanding of sources, atmosphere-land-ocean Hg dynamics and health effects, and consider the implications of Hg-control policies. Primary anthropogenic Hg emissions greatly exceed natural geogenic sources, resulting in increases in Hg reservoirs and subsequent secondary Hg emissions that facilitate its global distribution. The ultimate fate of emitted Hg is primarily recalcitrant soil pools and deep ocean waters and sediments. Transfers of Hg emissions to largely unavailable reservoirs occur over the time scale of centuries, and are primarily mediated through atmospheric exchanges of wet/dry deposition and evasion from vegetation, soil organic matter and ocean surfaces. A key link between inorganic Hg inputs and exposure of humans and wildlife is the net production of methylmercury, which occurs mainly in reducing zones in freshwater, terrestrial, and coastal environments, and the subsurface ocean. Elevated human exposure to methylmercury primarily results from consumption of estuarine and marine fish. Developing fetuses are most at risk from this neurotoxin but health effects of highly exposed populations and wildlife are also a concern. Integration of Hg science with national and international policy efforts is needed to target efforts and evaluate efficacy.

Short sleep duration and weight gain : a systematic review

Abstract: Objective: The recent obesity epidemic has been accompanied by a parallel growth in chronic sleep deprivation. Physiologic studies suggest sleep deprivation may influence weight through effects on appetite, physical activity, and/or thermoregulation. This work reviews the literature regarding short sleep duration as an independent risk factor for obesity and weight gain.

Rhythms of life: circadian disruption and brain disorders across the lifespan.

Abstract: Many processes in the human body — including brain function — are regulated over the 24-hour cycle, and there are strong associations between disrupted circadian rhythms (for example, sleep–wake cycles) and disorders of the CNS. Brain disorders such as autism, depression and Parkinson disease typically develop at certain stages of life, and circadian rhythms are important during each stage of life for the regulation of processes that may influence the development of these disorders. Here, we describe circadian disruptions observed in various brain disorders throughout the human lifespan and highlight emerging evidence suggesting these disruptions affect the brain. Currently, much of the evidence linking brain disorders and circadian dysfunction is correlational, and so whether and what kind of causal relationships might exist are unclear. We therefore identify remaining questions that may direct future research towards a better understanding of the links between circadian disruption and CNS disorders.

Current progress on understanding the impact of mercury on human health.

Abstract: Mercury pollution and its impacts on human health is of global concern. The authors of this paper were members of the Plenary Panel on Human Health in the 12th International Conference on Mercury as a Global Pollutant held in Korea in June 2015. The Panel was asked by the conference organizers to address two questions: what is the current understanding of the impacts of mercury exposure on human health and what information is needed to evaluate the effectiveness of the Minamata Convention in lowering exposure and preventing adverse effects. The authors conducted a critical review of the literature published since January 2012 and discussed the current state-of-knowledge in the following areas: environmental exposure and/or risk assessment; kinetics and biomonitoring; effects on children development; effects on adult general populations; effects on artisanal and small-scale gold miners (ASGM); effects on dental workers; risk of ethylmercury in thimerosal-containing vaccines; interactions with nutrients; genetic determinants and; risk communication and management. Knowledge gaps in each area were identified and recommendations for future research were made. The Panel concluded that more knowledge synthesis efforts are needed to translate the research results into management tools for health professionals and policy makers.