BACKGROUND: Hypospadias is one of the most common congenital anomalies in the world. Recently, increases in the prevalence of hypospadias have been reported in various countries including Japan. In this study, we examined whether the prevalence of hypospadias in Hokkaido, Japan, increased or not, using standardized diagnostic criteria. We also investigated the degree of its severity.
METHODS: We calculated prevalence of hypospadias using hospital records of hypospadias repair in Hokkaido. The prevalence from 1985 through 1997 by dividing the number of patients obtained from hospital records by the number of births.
RESULTS: The average prevalence of hypospadias in Hokkaido was 3.9 per 10, 000 births, and did not significantly changed (p=0.7). The average proportions of distal, proximal and chordee alone were 56.7%, 39.6% and 3.7%, respectively. The decrease in the proportion of the proximal type was statistically significant (p=0.05) for the entire time period, whereas the proportion of the distal type did not have a significant upward trend for the observed 13 years (p=0.1).
CONCLUSION: No significant changes in the prevalence of hypospadias existed in Hokkaido.

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BACKGROUND: Cardiovascular risk factors in children raise the possibility of cardiovascular disease later in life. We attempted to determine the current trends in cardiovascular risk factors among Japanese children.
METHODS: We examined fifth-graders at all the elementary schools in Iwata city in Japan every year from 1993 through 2001. We examined 4,673 boys and 4,484 girls, aged 10-11 years. Height, body weight, body mass index, and serum total cholesterol concentrations were measured. Regression analysis was used to evaluate the trends. The independent variable was the calendar year of the examination. The dependent variables were the anthropometric values and the serum total cholesterol concentration in each individual. The relationships between the year and the prevalence of hyperlipidemia and the prevalence of obesity were also examined.
RESULTS: Both the heights of the girls and the body weights of the both sexes were positively associated with the year. The body mass index in both girls and boys also showed positive relationships with the calendar year. In addition, there was an increase in the prevalence of obesity. Concerning the levels of cholesterol, positive regression coefficients were shown between the total cholesterol concentration and the year in both sexes. Furthermore, there was an increase in prevalence of hyperlipidemia.
CONCLUSION: These results indicate that during the past decade among Japanese children involved in the study, both the body mass index and the serum total cholesterol concentrations increased.

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BACKGROUND: Great public concern about health effects of dioxins emitted from municipal solid waste incinerators has increased in Japan. This paper investigates the association of adverse reproductive outcomes with maternal residential proximity to municipal solid waste incinerators.
METHODS: The association of adverse reproductive outcomes with mothers living within 10 km from 63 municipal solid waste incinerators with high dioxin emission levels (above 80 ng international toxic equivalents TEQ/m³) in Japan was examined. The numbers of observed cases were compared with the expected numbers calculated from national rates adjusted regionally. Observed/expected ratios were tested for decline in risk or peak-decline in risk with distance up to 10 km.
RESULTS: In the study area within 10 km from the 63 municipal solid waste incinerators in 1997-1998, 225, 215 live births, 3, 387 fetal deaths, and 835 infant deaths were confirmed. None of the reproductive outcomes studied here showed statistically significant excess within 2 km from the incinerators. However, a statistically significant peak-decline in risk with distance from the incinerators up to 10 km was found for infant deaths (p=0.023) and infant deaths with all congenital malformations combined (p=0.047), where a “peak” is detected around 1-2 km.
CONCLUSION: Our study shows a peak-decline in risk with distance from the municipal solid waste incinerators for infant of deaths and infant deaths with all congenital malformations combined. However, due to the lack of detailed exposure information to dioxins around the incinerators, the observed trend in risk should be interpreted cautiously and there is a need for further investigation to accumulate good evidence regarding the reproductive health effects of waste incinerator exposure.

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BACKGROUND: Genetic polymorphisms have proposed a new insight in smoking behavior. Genes in serotonin system are one of the candidates because of serotonin's role in mood regulation. A polymorphism C218A in intron 7 of the tryptophan hydroxylase (TPH) gene has been hypothesized in relation to smoking predisposition.
METHODS: We examined the association on two Japanese populations: one was from the first-visit outpatients of Aichi Cancer Center Hospital during 3-month period between April and June, 2001 (N=591), and the second was from the examinees who attended a health checkup program supported by the Nagoya municipal government in 2000 (N=446). Written documents on informed consent were obtained and lifestyle questionnaires were recorded. TPH C218A genotypes were determined by the polymerase chain reaction with confronting two-pair primers (PCR-CTPP) method.
RESULTS: The frequencies of the C- and A-allele were 52% and 48%, respectively, which was in Hardy-Weinberg equilibrium. As for current smoking status, no associations were statistically observed. It was, however, indicated that smokers with A/A genotype started smoking earlier in their life. Among male health examinees, mean ages at starting smoking were 18.7 (A/A), 19.9 (C/A), and 22.4 years (C/C), (P<0.01). Also, on the Aichi Cancer Center Hospital subjects aged 60 and older, mean ages were 19.0 (A/A), 20.2 (C/A), and 20.3 years (C/C) for males and 22.3 (A/A), 31.0 (C/A), and 33.0 years (C/C) for females (P<0.05).
CONCLUSIONS: The present study demonstrated that the TPH C218A polymorphism in intron 7 had no association with current smoking status in Japanese population. The hypothesis of early smoking initiation of A/A genotype was partially in agreement.

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BACKGROUND: It has been reported that the prevalence of asthma is on the rise in various countries; but studies on its effects on national medical expenditures are scarce.
METHODS: From the outcome of the “Estimates of National Medical Care Expenditures” and “Patient Survey” compiled by the Statistics and Information Department, Minister's secretariat, the Ministry of Health, Labour, and Welfare of Japan, medical expenditures on asthmatic patients in Japan were sequentially examined.
RESULTS: It was found that the percentage of asthmatic patients to the general medical care expenditures has been on the steady increase. A closer examination revealed that the percentage of asthmatic outpatients receiving care increased while those receiving care as inpatients decreased.
CONCLUSION: The relationships between the percentage of the number of asthmatic patients utilizing medical services and the expenditures for their care differed between inpatients and outpatients.

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