Hiroaki Itoh

Urinary phthalate monoesters and endometriosis in infertile Japanese women

Phthalates may act as an estrogen and are a potential risk factor for estrogen-related diseases such as endometriosis. We assessed the association between phthalate exposure and endometriosis in 166 consecutive women who presented at a university hospital for consultation regarding infertility. The subjects were interviewed and provided a urine specimen prior to a laparoscopic diagnosis of endometriosis. They were then categorized by the severity of endometriosis as controls (stages 0-I) and cases (stages II-IV). Urinary concentrations of the phthalate metabolites monoethyl phthalate, mono-n-butyl phthalate, monobenzyl phthalate, mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-oxohexyl) phthalate, and mono(2-ethyl-5-hydroxyhexyl) phthalate were measured in 57 cases and 80 controls using high-performance liquid chromatography isotope-dilution tandem mass spectrometry. Adjusted odds ratios for endometriosis in relation to dichotomized individual phthalate metabolites (standardized for creatinine) were calculated. No significant association between endometriosis and any urinary creatinine-adjusted phthalate monoester was seen. Adjusted odds ratio (95% confidence interval) for higher dichotomized MEHP by endometriosis was 1.57 (0.74-3.30). No monotonic trend was seen in urinary creatinine-adjusted concentration of phthalate metabolites by endometriosis stage (p=0.23-0.90). Our results do not support the hypothesis that higher urinary concentrations of phthalate metabolites are associated with the risk of endometriosis in infertile Japanese women.

Dietary cadmium intake and breast cancer risk in Japanese women: a case-control study.

Cadmium, an environmental pollutant, may act like an estrogen and be a potential risk factor for estrogen-dependent diseases such as breast cancer. We examined the hypothesis that higher dietary cadmium intake is associated with risk of overall and hormone receptor-defined breast cancer in Japanese women, a population with a relatively high cadmium intake. The study was conducted under a case-control design in 405 eligible matched pairs from May 2001 to September 2005 at four hospitals in Nagano Prefecture, Japan. Dietary cadmium intake was estimated using a food frequency questionnaire. Multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of breast cancer and its hormone-receptor-defined subtypes were calculated by tertile of dietary cadmium intake. We found no significant association between dietary cadmium and risk of total breast cancer in either crude or multivariable-adjusted analysis. Adjusted ORs for tertiles of cadmium intake were 1.00, 1.19, and 1.23 (95% CI, 0.76-2.00; P for trend=0.39) for whole breast cancer. Further, no significant associations were seen across strata of menopausal status, smoking, and diabetes in multivariable-adjusted models except for adjusted OR for continuous cadmium intake in postmenopausal women. A statistically significant association was found for estrogen receptor-positive (ER+) tumors among postmenopausal women (adjusted OR=1.00, 1.16, and 1.94 [95% CI, 1.04-3.63; P for trend=0.032]). Although the present study found no overall association between dietary cadmium intake and breast cancer risk, higher cadmium intake was associated with increased risk of ER+ breast cancer in postmenopausal women, at least at regular intake levels in Japanese women in the general population. Further studies are needed to confirm this association.

Serum organochlorines and breast cancer risk in Japanese women: a case-control study.

ObjectiveMost epidemiological studies of the association between breast cancer risk and exposure to organochlorine pesticides or polychlorinated biphenyls (PCBs), which are suspected endocrine disrupters and potential risk factors for human breast cancer, have been conducted in western countries, and the majority of results have been null and the rest inconsistent. Here, we examined these associations in Japanese women in the largest study in Asian women to date.MethodsThe study was a matched case–control study of breast cancer with 403 eligible matched pairs from May 2001 to September 2005 at four hospitals in Nagano Prefecture, Japan.MeasurementsSerum samples were measured for PCBs and nine pesticide-related organochlorines, including dichlorodiphenyltrichloroethane (DDT). Odds ratios of breast cancer or its hormone-receptor-defined subtypes according to serum organochlorines were calculated.ResultsNo increase in the risk of breast cancer was seen among women with higher serum concentrations of any organochlorine: o,p′-DDT, p,p′-DDT, p,p′-dichlorodiphenyldichloroethylene, hexachlorobenzene, β-hexachlorocyclohexane, trans-nonachlor, cis-nonachlor, oxychlordane, mirex, or PCBs. Rather, higher serum levels of cis-nonachlor, mirex, or total PCBs were associated with a decreased risk of breast cancerConclusionsOverall, these results suggest that breast cancer risk in Japan, a low-incidence country, is similar to that in western countries in terms of organochlorine exposure.

Plasma organochlorines and subsequent risk of prostate cancer in Japanese men: a nested case-control study.

Background Although accumulating evidence suggests that exposure to organochlorine pesticides and polychlorinated biphenyls (PCBs) may contribute to the development of prostate cancer, few investigations have used biological samples to classify exposure to specific organochlorines. To our knowledge, this is the first prospective study to investigate the association between blood levels of organochlorines and prostate cancer risk. Methods We conducted a nested case–control study using data from the Japan Public Health Center–based Prospective (JPHC) Study. A total of 14,203 men 40–69 years old who returned the baseline questionnaire and who provided blood samples were followed from 1990 to 2005. Using a mean follow-up period of 12.8 years, we identified 201 participants who were newly diagnosed with prostate cancer. Two matched controls for each case were selected from the cohort. We used a conditional logistic regression model to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for prostate cancer in relation to plasma levels of nine organochlorines: PCBs, dichlorodiphenyltrichloroethane (DDT), hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH), trans- and cis-nonachlor, oxychlordane, and mirex. Results No statistically significant association with total prostate cancer was seen for any plasma organochlorine, although we did observe an insignificant inverse association for plasma HCB and β-HCH. Total PCB in plasma was also inversely associated with advanced prostate cancer but without statistical significance. Conclusion Our results suggest that no overall association exists between prostate cancer and organochlorines at the levels measured in our study population.

Urinary bisphenol-A concentration in infertile Japanese women and its association with endometriosis: A cross-sectional study

ObjectivesBisphenol A (BPA), a raw material commonly used in the manufacture of resins such as polycarbonate and epoxy, is a possible xenoestrogen that is hypothesized to disrupt the human endocrine system. Humans are widely exposed to BPA. We investigated the urinary concentration of BPA in infertile Japanese women and its possible association with endometriosis.Materials and MethodsWe recruited 166 women (aged 20–45) who had complained of infertility and visited a university hospital in Tokyo. The subjects were interviewed and their urine samples were obtained prior to a laparoscopic diagnosis of endometriosis between January 2000 and December 2001. Urinary total BPA concentration in 140 eligible urine samples was then measured using enzymatic deconjugation of glucuronide and sulfate and high-performance liquid chromatography isotope-dilution tandem mass spectrometry.ResultsMedian (25th–75th percentile) unadjusted and creatinine-adjusted urinary BPA concentrations were 1.6 (0.69–2.8) μg/L and 0.80 (0.45–1.3) μg/g creatinine. No significant monotonic association of endometriosis with urinary BPA concentration was observed. Median urinary BPA concentration in women with stage 0–1 endometriosis (0.74 μg/g creatinine) did not significantly differ from that in those with stage II–IV endometriosis (0.93 μg/g creatinine) (p for difference=0.24).ConclusionsThis study, based on a larger number of samples than those in previous studies in Japan and using the most reliable analytical method currently available, showed that urinary concentrations of BPA in women who consulted a physician for infertility were not higher than those in other populations. Moreover, no association between urinary BPA concentration and endometriosis was found in this cross-sectional study.

Estimates of Annual Medical Costs of Work-related Low Back Pain in Japan

Little is reported regarding economic burden of work-related low back pain except for the United States. In the present study, annual medical cost of work-related low back pain in Japan was calculated based on the treatment fee per day, a total of days of treatment received for low-back pain of all causes, employment rates, and an estimated number of work-related low-back cases. The analysis indicated that, in 2011, the total annual medical cost for work-related low back pain was 82.14 billion yen, consisting of 26.48 and 55.66 billion yen for inpatients and outpatients, respectively. As well as for 2011, the costs were also estimated for 2008, 2005, and 2002. Whereas the total medical costs of work-related low back pain monotonically increased during 2002–2011, the costs for spine disorder (including spondylosis) have also increased in recent years. Work-related low back pain entails a considerable economic burden to Japanese society.

Sense of coherence is associated with reduced psychological responses to job stressors among Japanese factory workers

BackgroundJob stress is associated with adverse health effects. The present study was conducted to examine the association between sense of coherence (SOC), as advocated by Antonovsky, and psychological responses to job stressors among Japanese workers.MethodsA self-administered questionnaire containing a Japanese version of the 13-item SOC scale, the Brief Job Stress Questionnaire, and a self-rated health item were distributed to 1968 workers in X Prefecture. Anonymous responses were recovered by postal mail.ResultsComplete responses were received from 299 workers (response rate 15.2%, 191 males and 108 females) who consented to participate in the study. Participants were 186 office clerks, 38 sales representatives, 22 technical engineers, 16 service trade workers, eight information processing workers, eight technical experts, and 21 other workers of various types. SOC scores were associated with age, self-rated health, job title, and marriage status. According to regression analyses stratified by gender, SOC was inversely associated with tension, fatigue, anxiety, depression and subjective symptoms in males, and tension, depression and subjective symptoms in females. SOC was positively associated with vigor in both males and females.ConclusionsHaving a strong SOC may reduce worker’s negative job stress responses and increase their vigor. Longitudinal studies are required to confirm this finding.

A case-control study of the association between urinary cadmium concentration and endometriosis in infertile Japanese women.

Cadmium may act like an estrogen and be a potential risk factor for estrogen-related diseases such as breast cancer and endometriosis. Here, we tested the hypothesis that higher cadmium exposure is associated with endometriosis among infertile Japanese women in a hospital-based case-control study. We recruited consecutive female patients aged 20-45 years who had complained of infertility and presented to a university hospital in Tokyo. The subjects were interviewed and provided a urine sample prior to a laparoscopic diagnosis of endometriosis between January 2000 and December 2001. The severity of endometriosis was then dichotomized into controls (stage 0 and I) and cases (stage II-IV). We finally measured urinary total cadmium concentration in 54 cases and 74 controls as a biomarker of long-term cumulative exposure. Odds ratios were adjusted for average menstrual cycle length, body-mass index and smoking status using unconditional logistic regression. Results showed no association between endometriosis and urinary cadmium concentration. Medians (interquartile ranges) of urinary cadmium concentration in cases and controls were 0.53 (0.40-0.73) and 0.54 (0.34-0.76) microg/g creatinine, respectively (P for difference=0.88). Adjusted odds ratio (95% confidence interval) for the highest versus lowest tertile of urinary creatinine-adjusted cadmium concentration was 0.86 (0.30 to 2.49, P for trend=0.79). Our results do not support the hypothesis that higher urinary cadmium concentration is associated with the risk of endometriosis.

Cross-sectional Study on the Effects of Socioeconomic Factors on Lead Exposure in Children by Gender in Serpong, Indonesia

To elucidate the socioeconomic factors influencing lead exposure in elementary school children by gender, 108 children (56 male, 52 female), aged 6–7 years, were randomly selected from 39 elementary state schools in Serpong, Banten, Indonesia. Their parents were interviewed to obtain information on sociodemographic characteristics. Their blood lead (BPb) levels were measured by atomic absorption spectrophotometry. BPb concentrations were significantly higher in males than in females, i.e., 6.8 ± 2.0 (2.9–12.5) µg/dL and 5.9 ± 1.9 (3.1–11.7) µg/dL, respectively (p < 0.05). Lower socioeconomic status and well water use were associated with increased BPb concentrations, especially in females. The proportion of well water use was related to lower socioeconomic status. Lower socioeconomic status linked with well water drinking seemed to be associated with increased lead exposure in children in Serpong. Their exposure levels possibly varied according to gender differences in behavior. An intervention should be instituted among children in Serpong with BPb concentrations of 10 µg/dL or above.

Discrepancies Between the Supports Needed for Discharge of Patients With Terminal Cancer to Family Caregivers and What Supports Were Actually Provided in Japan: Assessment of Palliative Care Unit Nurses:

Objectives: Even if patients with terminal cancer hope to spend the rest of their lives at home, they are often unable to leave the hospital early due to their family caregivers’ anxiety. This study aimed to investigate in Japan the discrepancies between the supports needed by and actually provided by palliative care unit nurses (PCUNs) to the family caregivers for discharge of patients with terminal cancer. Methods: In this cross-sectional study, self-administered questionnaires including 6-point Likert-type scales assessing the reasons for difficulties in transition to home-based care were distributed to 1227 PCUNs. Using paired t tests, the differences between the scores on perceived importance and actual supports to family caregivers were examined. The supports actually provided were classified by factor analysis. The relationships between the PCUNs’ characteristics and mean scores on the supports in each category were examined using multiple regression analysis. Results: A total of 1023 (83.4%) completed questionnaires were returned. Scores on the actually provided supports for discharge to family caregivers were consistently and significantly lower than the corresponding scores on perceived importance for all 57 items (P < .001). Factor analysis revealed that the supports actually provided to the family caregivers had a 4-factor structure. Multiple regression analyses revealed that gaining experience in palliative care, receiving necessary training, cooperating with palliative care staff, and cooperating with local service providers were significantly associated with higher levels of actual supply of supports to family caregivers. Conclusion: Our findings suggest that PCUNs need to be encouraged to provide further support to family caregivers for the discharge of patients with terminal cancer.