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1.  Health symptoms related to pesticide exposure and agricultural tasks among rice farmers from northern Thailand 
The objective of this cross-sectional study was to investigate health symptoms related to occupational pesticide exposure and agricultural tasks in rice farmers.
Data on demographic variables and health symptoms associated with pesticide exposure were collected from 182 rice farmers (exposed subjects) and 122 non-farmers (controlled group) using interviews and measuring whole blood acetylcholinesterase (AChE) activity during August and October 2012.
Rice farmers had a significantly lower median AChE activity than the controls (9,594 vs. 10,530 U/L, respectively) and a significantly higher prevalence of difficulty in breathing and chest pain [odds ratio (OR) 2.8, P < 0.01 and OR 2.5, P < 0.05, respectively]. The prevalence of dry throat and cramp was associated with those farmers who sprayed and mixed pesticides (OR 2.5 and 2.6 for dry throat, OR 2.5 and 2.9 for cramp, respectively; P < 0.01). The prevalence of numbness and diarrhea was associated with those farmers who scattered seed (OR 2.2, P < 0.01 and OR 3.6, P < 0.05, respectively). The prevalence of numbness and increasing anxiety was also associated with those farmers who harvested crops (OR 3.6, P < 0.01 and OR 3.0, P < 0.05, respectively).
Our findings suggest that occupational pesticide exposure and agricultural tasks in the paddy field may be associated with the increasing prevalence of respiratory tract and muscle symptoms. This possibility warrants further investigation in more detail.
PMCID: PMC3890077  PMID: 23835647
Pesticides; Symptoms; Farmers; Acetylcholinesterase; Paddy field
2.  Association between maternal antenatal depression and infant development: a hospital-based prospective cohort study 
To examine the association between antenatal depression and infant development after controlling for confounding factors.
A hospital-based prospective cohort study (Hokkaido Study on Environment and Children’s Health) was conducted between July 2002 and October 2005 in Sapporo, Japan. Of 309 mothers who delivered at Sapporo Toho Hospital during the study period and who agreed with the clinical assessment of depression, 154 mother–infant pairs were eligible for analysis. Antenatal depression was assessed between the second and third trimesters using the Edinburgh Postnatal Depression Scale (EPDS), and infant development was assessed at 6 months by the Bayley Scales of Infant Development II (BSID-II). Data on potential confounders, including socioeconomic status, birth complications, postnatal depression and child care environment, were obtained from medical records and self-administered questionnaires. Univariable and multivariable analyses were conducted in which the EPDS score was entered as an independent variable and the BSID-II scores as a dependent variable, adjusting for confounders.
Although the antenatal EPDS score tended to be related to the BSID-II score in the univariable analysis, this correlation was lost in the multivariable analysis. However, based on a series of linear regression analyses, antenatal depression was found to be significantly related to shorter gestational age (β = −0.25, 95 % confidence interval (CI) [−1.20, −0.17]), and shorter gestational age was significantly related to a lower BSID-II (mental development) score (β = 0.23, 95 % CI [0.00, 0.00]).
Gestational age is an important confounder in the association between maternal antenatal depression and infant development. A delay in infant development may be related to a shorter gestational period caused by maternal depression during pregnancy.
PMCID: PMC3890074  PMID: 23913005
Maternal depression; Pregnancy; Infant development; Gestational age; Cohort study
3.  An emission model tracking the life cycle pathways of human pharmaceuticals in Korea 
Pharmaceuticals in the environment are of growing public health concern. The main objectives of this study were to develop a new emission estimation model, identify factors critical to reducing emission, and demonstrate the model’s applicability for screening and priority setting.
A new emission estimation model was developed covering the life cycle pathways of pharmaceuticals from supply to discharge into surface water. The emission estimates of the model were assessed by coupling with SimpleBox to give predicted concentrations and by comparing the predicted concentrations with measured concentrations in Korean surface waters for five selected pharmaceuticals (acetaminophen, cephradine, ibuprofen, mefenamic acid, and naproxen).
The sensitivity analysis revealed that the biodegradation rate in the sewage treatment plant and the excretion rate of pharmaceuticals were the most important factors influencing the emission rate. The uncertainty of the emission estimate was found to increase with increases in the value of the emission estimate. Once the intrinsic properties of a pharmaceutical (excretion rate, biodegradation rate, and removal rate by sludge separation) were given, the patient behavior parameters, such as participation in a Take-back program and rate of administration, were determined to have a strong influence on the emission estimate. In our study, the predicted and measured concentrations agreed with each other within one order of magnitude. Several management implications were drawn from the analysis of model outcomes.
The model outcomes, alone or in combination with toxicity data, may potentially be used for the purposes of screening, priority setting, and the design of management programs.
Electronic supplementary material
The online version of this article (doi:10.1007/s12199-013-0352-8) contains supplementary material, which is available to authorized users.
PMCID: PMC3890075  PMID: 23934391
Pharmaceuticals; Emission model; Pathway; Uncertainty; Sensitivity
4.  Management of clandestine drug laboratories: need for evidence-based environmental health policies 
Clandestine drug laboratories (CDLs) have been emerging and increasing as a public health problem in Australia, with methamphetamine being the dominant illegally manufactured drug. However, management and remediation of contaminated properties are still limited in terms of regulation and direction, especially in relation to public and environmental health practice. Therefore, this review provides an update on the hazards and health effects associated with CDLs, with a specific look at the management of these labs from an Australian perspective. Particularly, the paper attempts to describe the policy landscape for management of CDLs, and identifies current gaps and how further research may be utilised to advance understanding and management of CDLs and inform public health policies. The paper highlights a significant lack of evidence-based policies and guidelines to guide regulatory authority including environmental health officers in Australia. Only recently, the national Clandestine Drug Laboratory Guidelines were developed to assist relevant authority and specialists manage and carry out investigations and remediation of contaminated sites. However, only three states have developed state-based guidelines, some of which are inadequate to meet environmental health requirements. The review recommends well-needed inter-sectoral collaborations and further research to provide an evidence base for the development of robust policies and standard operating procedures for safe and effective environmental health management and remediation of CDLs.
PMCID: PMC3890076  PMID: 24002745
Clandestine drug laboratories; Australia; Environmental health practice; Research; Evidence-based policy
5.  Heat-related mortality risk model for climate change impact projection 
We previously developed a model for projection of heat-related mortality attributable to climate change. The objective of this paper is to improve the fit and precision of and examine the robustness of the model.
We obtained daily data for number of deaths and maximum temperature from respective governmental organizations of Japan, Korea, Taiwan, the USA, and European countries. For future projection, we used the Bergen climate model 2 (BCM2) general circulation model, the Special Report on Emissions Scenarios (SRES) A1B socioeconomic scenario, and the mortality projection for the 65+-year-old age group developed by the World Health Organization (WHO). The heat-related excess mortality was defined as follows: The temperature–mortality relation forms a V-shaped curve, and the temperature at which mortality becomes lowest is called the optimum temperature (OT). The difference in mortality between the OT and a temperature beyond the OT is the excess mortality. To develop the model for projection, we used Japanese 47-prefecture data from 1972 to 2008. Using a distributed lag nonlinear model (two-dimensional nonparametric regression of temperature and its lag effect), we included the lag effect of temperature up to 15 days, and created a risk function curve on which the projection is based. As an example, we perform a future projection using the above-mentioned risk function. In the projection, we used 1961–1990 temperature as the baseline, and temperatures in the 2030s and 2050s were projected using the BCM2 global circulation model, SRES A1B scenario, and WHO-provided annual mortality. Here, we used the “counterfactual method” to evaluate the climate change impact; For example, baseline temperature and 2030 mortality were used to determine the baseline excess, and compared with the 2030 excess, for which we used 2030 temperature and 2030 mortality. In terms of adaptation to warmer climate, we assumed 0 % adaptation when the OT as of the current climate is used and 100 % adaptation when the OT as of the future climate is used. The midpoint of the OTs of the two types of adaptation was set to be the OT for 50 % adaptation.
We calculated heat-related excess mortality for 2030 and 2050.
Our new model is considered to be better fit, and more precise and robust compared with the previous model.
PMCID: PMC3890078  PMID: 23928946
Heat-related mortality; Excess deaths; Climate change; Projection; Adaptation
6.  Association of geomagnetic disturbances and suicides in Japan, 1999–2010 
Previous studies have shown a positive relationship between geomagnetic disturbances and an increased incidence of suicide. The Japanese suicide rate is the ninth highest in the world, but there have been no reports examining the relationship between geomagnetic disturbance and the number of suicides, and, therefore, this paper examines this relationship.
The number of Japanese suicides per month from January 1999 to December 2010 was obtained, and it was found that a total of 262,596 males and 102,539 females committed suicide during this period. To adjust the other factors which affect the number of suicides, a multiple linear regression analysis with backward elimination was carried out, with the monthly number of suicides as the response variable and the monthly mean K index value, monthly mean number of sunspots, monthly mean unemployment rate, proportion of elderly people (%), monthly mean air pressure (hPa), monthly mean air temperature (°C), monthly mean humidity (%), and monthly mean day length (h) as the explanatory variables.
In the multiple linear regression analysis for males, the monthly mean K index value was associated with the monthly number of suicides, but in females, the monthly mean K index value was not associated with the monthly number of suicides.
In this study, we generated a hypothesis that geomagnetic disturbances may trigger male suicides.
PMCID: PMC3890079  PMID: 24005993
Suicide; Geomagnetic field; Geomagnetic storm; Electromagnetic field
7.  Indoor particle counts during Asian dust events under everyday conditions at an apartment in Japan 
Asian dust storms originating from arid regions of Mongolia and China are a well-known springtime phenomenon throughout East Asia. Evidence is increasing for the adverse health effects caused by airborne desert dust inhalation. Given that people spend approximately 90 % of their time indoors, indoor air quality is a significant concern. The present study aimed to examine the influence of outdoor particulate matter (PM) levels on indoor PM levels during Asian dust events under everyday conditions.
We simultaneously monitored counts of particles larger than 0.3, 0.5, 1, 2, and 5 μm using two direct-reading instruments (KC-01D1 airborne particle counter; Rion), one placed in an apartment room and another on the veranda, under everyday conditions before and during an Asian dust event. We also examined how indoor particle counts were affected by opening a window, crawling, and air purifier use.
An Asian dust event on 24 April 2012 caused 50- and 20-fold increases in PM counts in outdoor and indoor air, respectively. A window open for 10 min resulted in a rapid increase of indoor PM counts up to 70 % of outside levels that did not return to baseline levels after 3 h. An air purifier rapidly reduced PM counts for all particle sizes measured.
It is important to account for occupant behavior, such as window-opening and air purifier use, when estimating residential exposure to particulate matter.
PMCID: PMC3890080  PMID: 23934359
Indoor air; PM2.5; PM10; Dust storm; Asian dust
8.  A cross-sectional assessment of oxidative DNA damage and muscle strength among elderly people living in the community 
The mechanism by which muscle weakness leads to an increased risk of death remains a subject of interest. In this context, the aim of this study is to assess the relationship between urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) and muscle strength, and other risk factors contributing to poor muscle strength in older persons.
This was a cross-sectional study in which a total of 86 participants, both men and women, aged 65 years or above were screened for urinary 8-OHdG, and muscle strength as measured by handgrip strength.
Handgrip strength was lower in participants who had history of acute or chronic disease. Urinary 8-OHdG level was negatively associated with muscle strength, and the association remained after adjusting for confounding factors.
Urinary 8-OHdG is associated with muscle strength. These findings may be clinically relevant as there is a possibility of controlling oxidative DNA damage by healthy behaviors related to lifestyle.
PMCID: PMC3890081  PMID: 23868713
Oxidative stress; Handgrip strength; Cross-sectional study; Older persons; Lifestyle
9.  Association between teaching and support skills and subjective effectiveness of nutritional guidance of registered dietitians at hospitals in a Japanese prefecture 
The aim of this study is to clarify the association between teaching and support skills and the subjective effectiveness of nutritional guidance of registered dietitians working at hospitals.
We carried out a questionnaire survey of registered dietitians at hospitals in a Japanese prefecture. The utilization of nutritional teaching skills in nutritional guidance was investigated using a self-produced 36-item questionnaire that was designed to be mainly used for diabetic patients in 4 settings: first guidance, first assessment, contemplation stage, and preparation stage. The support skills were evaluated by Kikuchi’s Scale of Social Skills: 18 items. The subjective effectiveness of nutritional guidance was defined by the behavioral change of the patients after nutritional guidance as evaluated by a registered dietitian.
There were 75 respondents (response rate 46.6 %). Among the teaching skills, basic skills in an interview were often used, but some related to coaching skills were not in common use in nutritional guidance. Based on the results of principal component analysis, we created a scale for scoring the utilization of nutritional teaching skills in each setting. Multiple linear regression analysis illustrated that high subjective effectiveness of nutritional guidance was associated with high score of teaching skills in the preparation stage setting and high score of support skills.
These results show that, in addition to frequent use of nutritional teaching skills, improvement of support skills is also necessary to enhance the effectiveness of nutritional guidance.
PMCID: PMC3890082  PMID: 23982304
Registered dietitian; Nutritional guidance; Effectiveness; Support skills; Multiple linear regression analysis
11.  Attitudes towards cross-border reproductive care among infertile Japanese patients 
The attitudes towards cross-border reproductive care (CBRC) held by infertile Japanese patients have not been explored. The objective of the present study was to examine interest levels, preferred destinations, motivations, and sources of information related to CBRC. Our findings provide a general outline of CBRC and the future of reproduction and assisted reproductive technology (ART) in Japan.
The study used a cross-sectional design. Data were collected from 2,007 infertile Japanese patients from 65 accredited ART clinics in Japan (response rate, 27.4 %) via anonymous questionnaires.
Most of the infertile Japanese patients who responded denied using CBRC. However, by group, 171 (8.5 %) patients in non-donor in vitro fertilization, 150 (7.5 %) in egg donation, 145 (7.2 %) in pre-implantation genetic diagnosis, and 129 (6.4 %) in surrogacy said that, depending on the situation, they might travel abroad in the future. Older respondents were more likely to express an intention to travel overseas for egg donation in the future. The most popular destination for CBRC was the United States. Popular reasons for interest in CBRC among those considering or planning using this approach to third-party reproduction were that egg donation or surrogacy was unavailable or that obtaining ethical approval takes too long in Japan, whereas these processes are legal and affordable overseas. However, high cost was the most common reason for hesitancy regarding CBRC. Among the participants who were considering or planning to travel abroad for this purpose, TV, medical agencies, print media, and message boards on websites were popular sources of information, whereas doctors, friends, and patient self-help groups were not.
Although CBRC among infertile Japanese patients is not at present common, the demand for and use of this approach may increase in the future in the context of the increasingly aging population. Lack of regulation and unavailability of third-party reproduction is a major cause of CBRC among Japanese patients. Health care provider faces an urgent need for giving useful information for patients regarding CBRC.
PMCID: PMC3824726  PMID: 23749591
Cross-border reproductive care; Assisted reproductive technology; Third-party reproduction; Infertile Japanese patients
12.  Association between body mass index and mortality among institutionalized elderly adults in Japan 
The purpose of this study is to assess the association between body mass index (BMI) and mortality among nursing home residents in Japan.
A one-year prospective cohort study was conducted with 8,510 elderly individuals across 140 nursing homes. Baseline measurements included age, sex, height, weight, BMI, activities of daily living (ADL) (Barthel Index), and degree of dementia. Information regarding dates of discharge and mortality were also obtained to calculate person-years. Cox’s proportional hazards model was used to estimate hazard ratios.
Mean age and BMI were 84.3 [standard deviation (SD) 8.1] years and 20.6 (SD 3.8) kg/m2, respectively. Hazard ratios of mortality adjusted for sex, age, ADL, degree of dementia, and type of home were 2.4 [95 % confidence interval (CI): 1.9–3.1] for the 1st quintile of BMI (<17.3 kg/m2), 1.7 (95 % CI: 1.3–2.3) for the 2nd quintile (17.3–19.2 kg/m2), 1.5 (95 % CI: 1.2–2.0) for the 3rd quintile (19.3–21.1 kg/m2), and 1.2 (95 % CI: 0.9–1.6) for the 4th quintile (21.2–23.5 kg/m2) (P for trend <0.001), compared with the reference 5th quintile (23.6≤ kg/m2).
There was a clear inverse dose-dependent relationship between BMI and mortality. Future studies should be conducted to determine the effects of nutritional intervention on mortality in institutionalized elderly adults.
PMCID: PMC3824727  PMID: 23893379
BMI; Cohort studies; Frail elderly; Nursing homes; Mortality
13.  Ten years of progress in the Hokkaido birth cohort study on environment and children’s health: cohort profile—updated 2013 
The Hokkaido Study on Environment and Children’s Health is an ongoing cohort study that began in 2002. The study consists of two prospective birth cohorts, the Sapporo cohort (n = 514) and the Hokkaido large-scale cohort (n = 20,940). The primary goals of this study are to first examine the potential negative effects of perinatal environmental chemical exposures on birth outcomes, including congenital malformations and growth retardation; second, to evaluate the development of allergies, infectious diseases and neurodevelopmental disorders and perform longitudinal observations of the children’s physical development to clarify the causal relationship between these outcomes and environmental chemicals; third, to identify individuals genetically susceptible to environmental chemicals; finally, to identify the additive effects of various environmental factors in our daily life, such as secondhand smoke exposure or low folate intake during early pregnancy. In this paper, we introduce our recent progress in the Hokkaido study with a cohort profile updated in 2013. For the last ten years, we followed pregnant women and their offspring, measuring various environmental chemicals, i.e., PCB, OH-PCB and dioxins, PFCs (Perfluorinated Compounds), Organochlorine pesticides, Phthalates, bisphenol A and mercury. We discovered that the concentration of toxic equivalents (TEQ) of dioxin and other specific congeners of PCDF or PCDD have effects on birth weight, infants’ neurodevelopment and immune function. There were significant gender differences in these effects; our results suggest that male infants have more susceptibility to those chemical exposures than female infants. Interestingly, we found maternal genetic polymorphisms in AHR, CYP1A1 or GSTs that significantly modified the dioxin concentrations in maternal blood, suggesting different dioxin accumulations in the bodies of individuals with these genotypes, which would lead to different dioxin exposure levels. These genetic susceptibility factors influenced the body size of children born from mothers that either smoked or were passively exposed to tobacco smoke. Further studies investigating the correlation between epigenetics, the effects of intrauterine exposure to environmental chemicals and developmental factors related to health and disease are warranted.
PMCID: PMC3824728  PMID: 23959649
Birth cohort; PCB/dioxin; PFCs (PFAAs); Gene–environment interaction; Gender difference
14.  Distribution of and factors contributing to chronic kidney disease in a middle-aged working population 
To clarify the distribution of chronic kidney disease (CKD) and the factors contributing to its development and progression in middle-aged Japanese workers/employees.
This was a retrospective study involving 3,964 men and 2,698 women aged 35–64 years in 2009 who had been followed-up until 2003. Data on proteinuria determined with a dipstick and glomerular filtration rate estimated from serum creatinine concentration (eGFR) were collected in the annual health check-ups.
Proteinuria was detected in 2.9 and 1.1 % of the men and women, respectively, and total CKD was detected in 16.0 and 16.1 % of the men and women respectively. Moderate or severe CKD associated a high risk of cardiovascular diseases and end-stage kidney disease was found mostly in the male subjects [2.0 (men) vs. 0.6 % (women)]. High-risk CKD was found in 3.3 % of the men aged 55–64 years. A body mass index (BMI) of ≥30, hypertension, diabetes mellitus (DM), current smoking and some job types were independently related to the development of proteinuria, while age, BMI, hypertriglyceridemia, and job types were related to total CKD. The development of high-risk CKD was related to preceding mild CKD signs of reduced eGFR and proteinuria as well as to hypertension, DM, smoking, and job type.
Chronic kidney disease was found in 16 % of middle-aged workers with an equal prevalence in both sexes, while high-risk CKD was found mostly in men, of whom 3.3 % were aged 55–64 years. Obesity, hypertension, DM, smoking and some job types were related to the development and progression of CKD.
PMCID: PMC3824724  PMID: 23728725
Kidney disease; Proteinuria; Glomerular filtration rate; Risk factor; Health screening
15.  Acknowledgment to reviewers who served in 2013 
PMCID: PMC3824725
16.  Relationship between obesity and serum reactive oxygen metabolites in adolescents 
Various cross-sectional studies have revealed a significant positive relationship between systemic oxidative stress and obesity-related indices such as body mass index (BMI, kg/m2). However, little is known of the role of oxidative stress during adolescence. The aim of this study was to determine the association between obesity and serum reactive oxygen metabolites (ROM) in adolescents.
A total of 595 healthy junior high school students from northern Japan were enrolled in the study. Oxidative stress was evaluated by measuring serum levels of ROM. Obesity indices included BMI and percentage body fat (PBF). The analyses were stratified by sex and controlled for age and menarche. Partial correlation coefficients and analysis of covariance were also analyzed.
In female students, ROM levels increased with increasing BMI and PBF. Therefore, ROM levels were significantly higher in the underweight group than in the BMI-classified overweight–obese (P < 0.001) and normal weight groups (P < 0.05). ROM levels were significantly higher in the high PBF group than in the underweight (P < 0.05) and normal groups (P < 0.001).
The results of this study show that, regardless of menarche, obesity indicators such as BMI and PBF are correlated with the level of oxidative stress in female adolescents.
PMCID: PMC3824730  PMID: 23661093
Oxidative stress; Obesity; Sex; Healthy adolescent
17.  The influence of health-promoting lifestyles on the quality of life of retired workers in a medium-sized city of Northeastern China 
The aim of this study was to clarify the actual state of retired workers’ lifestyles and quality of life (QOL) in a medium-sized city of Northeastern China and to assess the relationship between these according to differences between gender groups.
The Chinese version of the Health Promotion Lifestyle Profile II (HPLP-II), the World Health Organization Quality of Life-BREF (WHOQOL-BREF), and demographic variables were used to measure 343 (aged 50–79 years) retired workers’ lifestyles and QOL. The results were analyzed using the t test, one-way analysis of variance, correlation analysis, and multiple linear regression analysis.
Among the six lifestyle subscales of HPLP-II, the highest mean score was for Interpersonal Relations (IR) and the lowest was for Health Responsibility (HR), which has not been reported previously. The youngest group (50–60 years) had higher scores for lifestyles and QOL than the other age groups. When the results were analyzed based on financial situation, the lowest income group (below ¥2000) had the poorest scores. Analysis according to gender group revealed different tendencies for the scores of lifestyle and QOL, as well as in the multiple regression analysis between variables.
Our results suggest that an effective approach to maintain a desirable lifestyle and QOL for retired workers at the regional level would be to introduce daily activities to improve HR and to maintain and enhance social support for the low-income populations. Further research is needed to understand the complex causal pathways between regional health and welfare factors, health behavior, and QOL.
PMCID: PMC3824729  PMID: 23700274
Quality of life; Lifestyle; Health Promotion Lifestyle Profile II; Retired workers
18.  Posttraumatic stress disorders in the Nanai after pollution of the Amur River: ethnocultural analysis 
Chemical pollution of the Amur River has seriously damaged traditions and caused posttraumatic stress disorder (PTSD) among the Nanai, the indigenous people living along this river. This study was performed to clarify the ethnographic characteristics of PTSD in this unique population.
The study group consisted of 75 male and 112 female randomly selected volunteers. PTSD severity measured using scores of the Impact of Event Scale – Revised (Total-I) and Clinical-Administered PTSD Scale (Total-C) was estimated according to demographic and ethnocultural backgrounds, clinical status, and ethnopsychological attitudes toward the Amur River.
The differences in averages of Total-I and Total-C were not always the same in the groups divided by ethnographic information. Logistic regression analysis with a dependent variable, possibly without PTSD (Total-I <34 and Total-C <40)/possibly with PTSD (either Total-I ≥34 or Total-C ≥40), and categorical independent variables using ethnographic information extracted a low score when ‘priority values’ and ‘the Amur River for me is’ was “profession” and a high score when ‘dominant role in spousal relationship’ was “self,” when ‘predominant forms of response in stressful situations’ was “try to organize,” when ‘preferred method of medical treatment’ was specific for the Nanai, when “rely on something mystical” was manifested, and when the Amur River was believed to be “sacred”.
Those with a pragmatic attitude were less likely to have PTSD. However, those who were required to make decisions within close relationships and were intimate with the Nanai tradition and the Amur River had increased likelihood of PTSD.
PMCID: PMC3824732  PMID: 23780747
Indigenous people Nanai; Posttraumatic stress disorders (PTSD); Impact of Event Scale – Revision (IES-R); Clinical-administered PTSD Scale (CAPS); Ethnocultural analysis
19.  Variation and seasonal patterns of suicide mortality in Finland and Sweden since the 1750s 
Suicide mortality varies in both the short and long term. Our study examines suicide mortality in Finland and Sweden from the 1750s until today. The aim of our study is to detect any seasonal peaks in suicide rates and examine their temporal evolution to suggest a mechanism that may explain such peaks.
We acquired the study material from the Finnish and Swedish cause of death statistics (257,341 deaths by suicide) and the relevant population gender structure data. We then separately calculated the annual male and female suicide rates per 100,000 inhabitants. We analysed the suicide peaks, calculating factors of proportionality for the available data by dividing the suicide rates in the peak months (May and October) by the annual suicide rates.
Suicide rates in Finland and Sweden peak twice a year. Both men and women in both countries most often commit suicide in May. There is another peak in October, with the exception of Finnish men. These suicide peaks coincide with a temperature increase in May and the biggest annual drop in temperature in October. We also observed a monotonic long-term change in the Swedish statistics, but not in the Finnish data. Our hypothesis is that seasonal variation in suicide rates may be caused by abrupt temperature changes twice a year that trigger the activity in brown adipose tissue and deepen depression.
While the overall suicide mortality rates varied considerably, the monthly proportions in May did not. This finding suggests a routine factor underlying the spring peak in suicide mortality.
PMCID: PMC3824731  PMID: 23835646
Population; Season; Suicide rate; Thermal stress; Time
20.  Association of ambient air pollution and meteorological factors with primary care visits at night due to asthma attack 
The association of outdoor air pollution and meteorological elements with primary care visits at night due to asthma attack was studied.
A case–crossover study was conducted in a primary care clinic in Himeji City, Japan. The subjects were 956 children aged 0–14 years who visited the clinic with an asthma attack between the hours of 9 p.m. and 6 a.m. Daily concentrations of particulate matter, ozone, nitrogen dioxide, and a number of meteorological elements were measured, and a conditional logistic regression model was used to estimate odds ratios (ORs) of primary care visits per unit increment of air pollutants or meteorological elements. The analyses took into consideration the effects of seasonality.
Of the 956 children, 73 (7.6 %) were aged <2 years and 417 (43.6 %) were aged 2–5 years. No association between daily ozone levels and primary care visits due to asthma attack at night in the spring or summer was found. An inverse relation between suspended particulate matter and primary care visits due to asthma attack was detected in the winter. ORs in the summer per degree increment in daily mean temperature was 1.31 [95 % confidential interval (CI) 1.09–1.56], and ORs in the autumn per hourly increment in daily hours of sunshine was 0.94 (95 % CI 0.90–0.99).
The findings of our study fail to support any association between daily mean concentration of air pollutant and primary care visits at night. However, we did find evidence indicating that certain meteorological elements may be associated with primary care visits
PMCID: PMC3773095  PMID: 23640199
Air pollution; Asthma; Ozone; Meteorological elements; Particulate matter
21.  Living alone and cardiovascular health status in residents of a rural village of coastal Ecuador (The Atahualpa Project) 
Knowledge of region-specific factors affecting the cardiovascular health (CVH) is mandatory to reduce the growing burden of stroke and ischemic heart disease in rural areas of Latin American. We conducted a population-based case–control study to assess the CVH status of Atahualpa residents—a rural village representative of Coastal Ecuador—according to their living arrangements.
All Atahualpa residents aged ≥40 years and free of stroke or ischemic heart disease that lived alone were identified during a door-to-door census, and their CVH status was compared to that of a sample of residents that lived with relatives. Four controls individually matched for age, gender, education, job and alcohol intake, and randomly selected from different households, were selected for each case-person.
A total of 185 persons (37 who lived alone and 148 matched controls) were included. A poor CVH status was found in 89.2 % case-patients and 72.3 % controls (p = 0.03). We found significantly worse levels of physical activity (p < 0.0001) and non-significant trends for worse healthy diet and glucose levels among case-persons than controls.
This study suggests that social isolation is associated with a worse CVH in rural coastal Ecuador. An ongoing community-based intervention may prove effective to improve CVH status in these social isolated persons.
PMCID: PMC3773088  PMID: 23733495
Social isolation; Cardiovascular health; Case–control study; Ecuador; Atahualpa
22.  Use of organic solvents in large research institutions in Japan 
Laboratories in research institutions use organic solvents in research and development. Nevertheless, the types of solvents in use have been seldom reported. This study was initiated to elucidate types of organic solvents used in large research institutions in Japan, with a focus on possible different use among research fields.
In 2010–2011, 4517 laboratories in seven large research institutions were visited. In accordance with legal stipulations, air in each laboratory was collected in polyvinyl fluoride bags and analyzed by direct injection into a gas-chromatograph for 47 types of organic solvents. In evaluation, the laboratories were grouped by 5 research fields, i.e., agriculture, biology, medicine, natural science, and technology and engineering.
Types of organic solvents commonly used in research activities were not diverse. Those commonly used were chloroform and 1,2-dichloroethane out of 7 Group 1 organic solvents (with high toxicities); 6 organic solvents, i.e., acetone and methyl alcohol in general, ethyl acetate, hexane and toluene in technology and engineering laboratories; and xylenes in medical fields out of 40 Group 2 organic solvents (with relatively low toxicities). Judging from solvent vapor concentrations, work environments in more than 99 % of laboratories were considered adequate. Nevertheless, use of chloroform in high-performance liquid chromatography (HPLC) resulted in inadequate environments in 30 laboratories (0.7 %).
Organic solvents commonly used were not very diverse. Work environments in research laboratories were generally good, but the environment with use of chloroform in HPLC analysis remained yet to be improved.
PMCID: PMC3773089  PMID: 23404090
Chloroform; Organic solvents; Research laboratory; Unmixed solvents; Xylenes
23.  Changes in subjective symptoms and allergy state among medical students exposed to low-level formaldehyde 6 months after completion of a gross anatomy dissection course 
Our purpose was to clarify whether subjective symptoms of low-level formaldehyde (FA) exposure in medical students were transient or persistent and to investigate whether the allergy state changed as a result of exposure.
We surveyed the prevalence of medical students’ subjective symptoms and their allergy state before, during, and 6 months after completion of a gross anatomy dissection course by using two self-administrative questionnaires. Students completed the first survey at the end of the anatomy course to assess symptoms before and during the course. The second survey was completed 6 months after course completion.
The prevalence of most subjective symptoms was lower 6 months after the course than during the course. The major symptoms experienced during the course were eye fatigue, runny nose, and dry eyes. The most common symptom 6 months after the course was eye fatigue. Four students continued to experience symptoms even after course completion. Three students developed symptoms only after course completion. Forty-eight students had allergies before the course began and the severity of the allergies did not change after the course. Additionally, the prevalence of most subjective symptoms 6 months after the course was lower than before the course. The patterns of subjective symptoms in the three periods differed between male and female students; the prevalence of most subjective symptoms tended to be higher in females.
Subjective symptoms resulting from FA exposure during a gross anatomy course were transient and did not affect students’ allergy states.
PMCID: PMC3773090  PMID: 23588414
Low-level FA exposure; Gross anatomy dissection course; Subjective symptoms; Allergy; Six months after completion of the course
24.  In vivo modulation of iNOS pathway in hepatocellular carcinoma by Nigella sativa 
Nitric oxide (NO) and inducible nitric oxide synthase enzyme (iNOS) have been implicated in various tumors. Hepatocellular carcinoma is a highly aggressive form of solid tumor. The lack of effective therapy necessitates the introduction of novel therapeutic strategies to counter this disease. Nigella sativa (NS) has been shown to have specific health benefits. The aim of this study was to investigate the in vivo modulation of the iNOS pathway by NS ethanolic extract (NSEE) and the implications of this effect as an antitumor therapeutic approach against diethylnitrosamine (DENA)-induced hepatocarcinogenesis.
Rats were divided into four groups, normal control, NSEE control, cancer control, and NSEE-DENA groups. The diagnosis of cancer was based on alpha-fetoprotein (AFP) levels and histological variations. Serum NO, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) levels and serum iNOS activity were measured. Liver iNOS expression was investigated by reverse transcriptase (RT)-PCR and western blot assays.
Serum AFP, NO, TNF-α, and IL-6 levels and iNOS enzyme activity were significantly increased in rats treated with DENA. Significant up-regulation of liver iNOS mRNA and protein expression was also observed. Subsequent treatment with NSEE significantly reversed these effects and improved the histopathological changes in malignant liver tissue which appeared after treatment with DENA, without any toxic effect when given alone.
These results provide evidence that attenuation of the iNOS pathway and suppression of the inflammatory response mediated by TNF-α, and IL-6 could be implicated in the antitumor effect of NSEE. As such, our findings hold great promise for the utilization of NS as an effective natural therapeutic agent in the treatment of hepatocarcinogenesis.
PMCID: PMC3773091  PMID: 23609474
Nigella sativa ethanolic extract; Hepatocellular carcinoma; Inducible nitric oxide synthase; Nitric oxide; Tumor necrosis factor-alpha
25.  The 14-item health literacy scale for Japanese adults (HLS-14) 
Most existing tools for measuring health literacy (HL) focus on reading comprehension and numeracy in English speakers. The aim of this study was to develop a generic HL measure for Japanese adults.
A questionnaire survey was conducted among participants in multiphasic health examinations at a Japanese healthcare facility. HL was measured using the 14-item health literacy scale (HLS-14) that was adapted from the HL scale specific to diabetic patients developed by Ishikawa and colleagues. The 14 items consist of five items for functional HL, five items for communicative HL, and four items for critical HL. The reliability and validity of the HLS-14 were assessed among 1,507 eligible respondents aged 30–69 years.
Explanatory factor analysis produced a three-factor solution that was very similar to the original HL scale. Cronbach’s alpha indicated satisfactory internal consistency of the functional, communicative, and critical HL scores (0.83, 0.85, and 0.76, respectively). There were no floor or ceiling effects in each HL score. Confirmatory factor analysis revealed an acceptable fit of the three-factor model (comparative fit index = 0.912, normed fit index = 0.905, root mean square error of approximation = 0.082). When the two groups with a total HL score above and below the median (50), respectively, were compared, those who could obtain medication information satisfactorily and those who wanted to participate in making medication decisions were more frequently observed in the group with the higher score.
The HLS-14 demonstrated adequate reliability and validity as a generic HL measure for Japanese adults. This scale can be utilized for measuring functional, communicative, and critical HL in the clinical and public health contexts.
PMCID: PMC3773092  PMID: 23689952
Health literacy; Adult; Japan; Questionnaire; Validity

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