Vitamin D insufficiency, or a low vitamin D status, is a prevalent condition worldwide. However, there have been no studies addressing this public health issue until recently. In this review article, a summary of a series of studies conducted by the author and his colleagues to determine whether the vitamin D status of Japanese people is adequate and how their vitamin D status affects bone mass and bone metabolism is presented. The observational studies conducted by our group revealed that vitamin D insufficiency does not seem to be a serious problem among active elderly people, but that elderly people with a low level of activities of daily living (ADL) are at a very high risk of vitamin D insufficiency. In young adults, a high intact PTH concentration due to vitamin D insufficiency, which adversely affects their bone mass, is common, suggesting that vitamin D nutrition, as well as dietary calcium intake, should be improved. However, the effects of vitamin D insufficiency among elderly Japanese on bone metabolism, bone mass, and fractures have not been clarified, and should be studied further to determine whether specific preventive strategies, such as vitamin D supplementation, are required for this high-risk group. Intervention studies targeting Japanese populations are required to further address this issue.

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Objectives: To clarify the effect of the female hormone estradiol (Est) on heme biosynthesis in lead-poisoned rabbits, parameters indicating lead exposure, such as free erythrocyte protoporphyrin (FEP) level and δ-aminolevulinic acid dehydratase (ALA-D) activity, were determined.
Methods: Twenty-six male Japanese white rabbits (body weight (BW), 3 kg) were divided into four groups: I (control), II (Est), III (Pb), IV (Est+Pb). About 3 weeks after castration, Est (3 mg/kg of BW) was injected intramuscularly, and 2 weeks thereafter, lead (1.2 mg/kg of BW) was injected intravenously. After the initial injection of each of these substances, the same dose of each of these substances was injected once a week until the 9th week.
Results: In groups III and IV, FEP level increased and ALA-D activity in the erythrocytes, bone marrow and liver decreased with an increase in lead concentration in blood. FEP level decreased significantly (p<0.01) in the 8th and 10th weeks after Est injection in group IV compared to with that in group III and was not elevated in group II compared with that in group I. ALA-D activity in the erythrocytes, bone marrow and liver increased significantly in group II compared with that in group I, whereas Ht and Hb levels decreased in group II compared with those in group I, and decreased in group IV compared with those in group III. The level of iron in plasma (Fe-P) was within the normal range during experiment.
Conclusions: In this study, Est did not increase FEP level. From the above results regarding FEP level and ALA-D activity, Est may prevent an increase in FEP level caused by lead. Ht and Hb levels, which are the parameters of anemia, decreased mainly as a result of Est exposure rather than lead exposure.

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Objectives: The Community Health Act came into effect in 1997 in Japan. This act altered the work system for public health nurses (PHNs) in public health centers (PHCs) nationwide from region-specific to service-specific work. Such major changes to working environment in the new system seem to be exposing PHNs to various types of stress. The present study examined whether prevalence of burnout is higher among PHNs in charge of mental health services (psychiatric PHNs) than among PHNs in charge of other services (non-psychiatric PHNs), and whether attributes of emergency mental health care systems in communities are associated with increased prevalence of burnout.
Methods: A questionnaire including the Pines burnout scale for measuring burnout was mailed to 525 psychiatric PHNs and 525 non-psychiatric PHNs. The 785 respondents included in the final analysis comprised 396 psychiatric PHNs and 389 non-psychiatric PHNs.
Results: Prevalence of burnout was significantly higher for psychiatric PHNs (59.2%) than for non-psychiatric PHNs (51.5%). When prevalence of burnout in each group was analyzed in relation to question responses regarding emergency service and patient referral systems, prevalence of burnout for psychiatric PHNs displayed significant correlations to frequency of cases requiring overtime emergency services, difficulties referring patients, and a feeling of “restriction”.
Conclusions: Prevalence of burnout is high among psychiatric PHNs, and inadequate emergency mental health service systems contribute to burnout among these nurses. Countermeasures for preventing such burnout should be taken as soon as possible.

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Objectives: Nanomaterials have numerous potential benefits for society, but the effects of nanomaterials on human health are poorly understood. In this study, we aim to determine the genotoxic effects of chronic exposure to nanomaterials in various cell lines.
Methods: Chinese hamster ovary (CHO) cells, human epidermoid-like carcinoma (Hela) cells and human embryonic kidney 293 (HEK293) cells were treated with the water-soluble fullerene C₆₀(OH)₂₄ for 33–80 days. Cell proliferation, cytotoxic analysis and micronucleus tests were performed.
Results: When treated with C₆₀(OH)₂₄ (0, 10, 100, or 1000 pg/ml) for 33 days, both the HEK293 and Hela cells showed increased cell proliferation, but cellular lactate dehydrogenase (LDH) activity was not affected. After long-term exposure (80 days) to C₆₀(OH)₂₄ (0, 10, 100, or 1000 pg/ml), the CHO, Hela and HEK293 cells showed increased genotoxicity on the micronucleus test.
Conclusion: This study suggests that nanomaterials, such as C₆₀(OH)₂₄, have genotoxic effects.

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Objectives: To determine the incidence of sepsis in Japanese intensive care units (ICUs) and to evaluate the impact of sepsis on mortality and length of stay (LOS).
Methods: Using the JANIS database for the period between June 2002 and June 2004, 21,895 eligible patients aged ³16 years, hospitalized in 28 participating ICUs for ³24 hours, were monitored until ICU discharge. Adjusted hazard ratio (HR) with 95% confidence interval (CI) for the incidence of sepsis was calculated using Cox's proportional hazard model. Standardized mortality ratio (SMR) was calculated on the basis of the crude mortality in patients without nosocomial infection (NI) for respective APACHE II categories. Mean LOS for survivors was assessed by two-way analysis of variance with adjustment for APACHE II.
Results: Sepsis was diagnosed in 450 patients (2.1%), with 228 meeting the definition on ICU admission and 222 during the ICU stay. The overall incidence of sepsis was 1.02/100 admissions or 2.00/1000 patient-days. A significantly higher HR for the incidence of sepsis was found in men (1.54, 95% CI: 1.14–2.07), APACHE II ³21 (2.92, 95% CI: 1.92–4.44), ventilator use (3.30, 95% CI: 1.98–5.49), and central venous catheter use (3.45, 95% CI: 1.90–6.28). SMR was determined to be 1.18 (95% CI: 0.82–1.21) in NI patients without sepsis and 2.43 (95% CI: 1.88–3.09) in NI patients with sepsis. Mean LOS for survivors was calculated to be 11.8 days (95% CI: 11.3–12.4) in NI patients without sepsis and 15.0 days (95% CI: 13.3–17.0) in NI patients with sepsis compared with 3.8 days (95% CI: 3.8–3.9) in patients without NI.
Conclusions: Sepsis is not very common in Japanese ICUs, but its development leads to further increases in mortality and LOS in patients with NI.

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Objective: The aim of this study is to clarify the factors related to the handedness and footedness of twins using two of the largest databases on Japanese twins available.
Methods: The first group consisted of 1,131 twin pairs, all school children either 11 or 12 years old (S group), and the second group consisted of 951 twin pairs of different ages (1–15 years) in several maternal associations (M group). All data were gathered using a questionnaire. Factors associated with the handedness or footedness of twin individuals were analyzed by univariate and multivariate logistic analyses.
Results: Multivariate logistic analysis showed that for handedness, birth year (OR=1.02) and neonatal asphyxia (OR=1.62) were selected in the S group, and sex (OR=1.34), the age of twins (OR=1.56), parity (OR=1.31), gestational age (OR=1.58), and family history (OR=1.82) were selected in the M group. For footedness, birth complications (OR=1.37) were selected in the S group, and sex (OR=1.33), the age of twins (OR=1.69), gestational age (OR=1.83), and family history (OR=2.49) were selected in the M group. Factors associated with handedness and footedness specific to twins, such as zygosity, placentation, birth order within twin pairs and the sex of the cotwin, were not found, although being a twin might have some effects.
Conclusion: It was concluded that factors that affect handedness or footedness in general, such as sex, birth year, age, parity, neonatal asphyxia, gestational age, birth complications, and family history, seem to have stronger effects on handedness and footedness than being a twin.

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Objective: The aim of this study is to determine whether a questionnaire-based method using the Veterans Specific Activity Questionnaire (VSAQ) is a practical tool for the development of a safe exercise program to prevent a reduction in physical performance.
Methods: One hundred and twenty-one senior residents of Yakage, Okayama, agreed to voluntarily participate in this study. They were asked to complete a questionnaire for information on age, sex, subjective health status, exercise habits and VSAQ. We investigated the relationship between age and exercise capacity predicted by VSAQ (predicted metabolic equivalents (METs)). In addition, for 36 out of the 121 participants, we performed a 6-min walk distance test (6MD) and investigated whether its results correlate with the predicted METs. Furthermore, we prepared a modified VSAQ and examined its practicality in the evaluation of the exercise capacity of Japanese elderly (n=50).
Results: We found that the predicted METs correlate well with age. Habitual exercise and subjective health status did not affect the predicted METs. A significant correlation was observed between the predicted METs and the results of 6MD (r=0.56, p<0.001). We also found that certain activities included in the original VSAQ are unfamiliar to Japanese elderly; thus, we made a few modifications to the original VSAQ in order to evaluate the physical fitness of Japanese elderly. The number of inadequate answers was reduced by employing the modified VSAQ.
Conclusion: These findings imply that the modified VSAQ is useful in evaluating the exercise capacity of Japanese elderly adequately and is a practical scale for safe exercise.

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Objectives: We determined the relationship between abdominal circumference and the concentration of nitric oxide (NO), an endothelial cell product known to play an important role in the regulation of vascular tone and thrombocyte activations.
Methods: Subjects were 177 men and 339 women aged 40 or over who were free from a history of diabetes or malignancy. Analysis of covariance was applied to examine the gender-specific and smoking-status-specific associations of abdominal fat volume measured as waist circumference, waist-hip ratio, and waist-to-stature ratio, with serum NO level represented by the concentration of NO metabolites (NOx; nitrate plus nitrite).
Results: Although men showed no statistical association between abdominal fat accumulation and NOx concentration, abdominal adiposity seemed to inversely affect the serum NOx concentration of never- and current-smoking women.
Conclusion: Our results suggest that a reduction in NO bioactivity occurs with abdominal fat accumulation in women. The underlying biological mechanism might involve adipocytokines secreted from visceral fat, but is yet to be elucidated.

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