Time trend of cadmium intake in Korea.

OBJECTIVES: The aim of this study was to elucidate past and current levels of cadmium (Cd) intake among the general populations in Korea. METHODS: For this purpose, publications reporting dietary intake of cadmium (Cd-D), cadmium concentration in blood (Cd-B) and that in urine (Cd-U) in Korea were retrieved through literature survey for a period from 1975 to 2015. RESULTS: In practice, 9, 21 and 14 articles were available on Cd-D, Cd-B and Cd-Ucr (Cd-U as corrected for creatinine concentration), respectively. Linear regression analyses of the reported values as a function of years (i.e., the year when each survey was conducted) showed steady decreases in all of the three exposure markers of Cd-D, Cd-B and Cd-U(cr). Factors possibly contributing for the reduction were discussed including the government-set guideline of 0.2 mg/kg for rice and changes in food habits among general populations. CONCLUSIONS: There have been steady decreases in Cd-D, Cd-B and Cd-U(cr). The current estimates for Cd-D, Cd-B and Cd-Ucr were 6.0-7.4 µg/day, 0.73-0.83 µg/L and 0.60-0.95 µg/g cr, respectively.

Iodine intake by adult residents of a farming area in Iwate Prefecture, Japan, and the accuracy of estimated iodine intake calculated using the Standard Tables of Food Composition in Japan.

OBJECTIVES: Iodine intake by adults in farming districts in Northeastern Japan was evaluated by two methods: (1) government-approved food composition tables based calculation and (2) instrumental measurement. The correlation between these two values and a regression model for the calibration of calculated values was presented. METHODS: Iodine intake was calculated, using the values in the Japan Standard Tables of Food Composition (FCT), through the analysis of duplicate samples of complete 24-h food consumption for 90 adult subjects. In cases where the value for iodine content was not available in the FCT, it was assumed to be zero for that food item (calculated values). Iodine content was also measured by ICP-MS (measured values). RESULTS: Calculated and measured values rendered geometric means (GM) of 336 and 279 µg/day, respectively. There was no statistically significant (p > 0.05) difference between calculated and measured values. The correlation coefficient was 0.646 (p < 0.05). DISCUSSION: With this high correlation coefficient, a simple regression line can be applied to estimate measured value from calculated value. A survey of the literature suggests that the values in this study were similar to values that have been reported to date for Japan, and higher than those for other countries in Asia. CONCLUSIONS: Iodine intake of Japanese adults was 336 µg/day (GM, calculated) and 279 µg/day (GM, measured). Both values correlated so well, with a correlation coefficient of 0.646, that a regression model (Y = 130.8 + 1.9479X, where X and Y are measured and calculated values, respectively) could be used to calibrate calculated values.

Estimation of daily cadmium intake from cadmium in blood or cadmium in urine.

OBJECTIVES: It would be quite convenient if daily dietary cadmium intake (Cd-D) can be estimated either from Cd in blood (Cd-B) or from Cd in urine (Cd-U). The aim of the study was to examine if Cd-D can be estimated from Cd-B or Cd-U. METHODS: The data available in a previous publication were employed for regression analyses between Cd-D and Cd-B, and between Cd-D and Cd-U. 30 sites in various prefectures throughout Japan were surveyed and 20 adult women/site on average provided food duplicate, peripheral blood, and second morning urine samples. Geometric means were taken as representative values and employed in regression analyses. RESULTS: Cd-D, Cd-B, and Cd-U(cr) [i.e., Cd-U after correction for creatinine (cr) concentration] distributed in ranges of 12.5-70.5 µg/day, 0.46-3.98 µg/l, and 1.16-11.02 µg/g cr, respectively. A close correlation was observed between Cd-D and Cd-B, and also between Cd-D and Cd-U(cr) with r = 0.76 and r = 0.79 (p < 0.001 for both), respectively. Both regression lines passed close to the origins. Application of 1.23 µg Cd/l blood and 1.26 µg Cd/g cr in urine (average levels for adult Japanese women) to the regression equations gave 16.5 and 11.5 µg Cd/day. CONCLUSIONS: The analyses suggested that it may be possible to estimate Cd-D from Cd-B or Cd-U. Cd-B-based estimation should be more respected. As variations in the estimation parameters and estimated values are inherent to field surveys, care should be taken in the application of the study results. Application on a group basis (and not on an individual basis) should be considered.

Food intake survey of kindergarten children in Korea: Part 1 food, energy, and nutrient intake.

OBJECTIVES: Nutrient intakes of children were surveyed at the time when a nation-wide shift took place in the Republic of Korea from agriculture-based to industrialized society. Taking advantage of the survey locations (see below), possible delay in nutritional improvement in rural areas (as compared with that in an urban area) was also examined. METHODS: In total, 108 4- to 6-year-old children (boys and girls in combination) in 4 kindergartens (KGs; 1 in Seoul and 3 in Jeju Island) participated in the survey in 2003-2004. 24-h food duplicate samples were prepared by the mother of each child. Food items in each duplicate sample were separated and coded with reference to the Dietary Reference Intake for Koreans (the 2005 version). Nutrient intake of the day was estimated from the code and weight followed by summation for daily intake. RESULTS: The children in the KG in Seoul studied were younger, and therefore were smaller in body size than those in other KGs. Thus, it was considered necessary to evaluate nutrient intake not only on a daily basis, but after adjustment for body weight. The AM daily intake of energy (protein in parenthesis) for the 108 children was 1479 kcal (55 g)/day or 69.8 kcal (2.6 g)/kg body weight/day. Evaluation by individual nutrient suggested that the intake was sufficient for almost all nutrients except for sodium and potassium. Sodium and potassium intake (2285 and 1840 mg/day, respectively) was in excess and insufficient, respectively, with potential risk of inducing hypertension later in life. CONCLUSIONS: Inter-KG difference was not remarkable and therefore urban-rural difference was not apparent. Nutrient intakes as a whole appeared to be sufficient urban and rural areas. Nevertheless, excess Na intake coupled with insufficient K intake was a common problem.

Food intake survey of kindergarten children in Korea: Part 2 increased dietary intake of tin possibly associated with canned foods.

OBJECTIVES: Dietary intake of tin (Sn) may be increased in some children in kindergartens in Korea. The present study was intended to examine this possibility and clarify the extent of the elevation. METHODS: 24-hour food duplicate and spot urine samples were collected in 2003-2004 from 108 4-6-year-old children (boys and girls combined) in 4 kindergartens (1 in Seoul and 3 in Jeju Island), as reported in a previous publication. These samples were employed in the present analyses to examine tin levels in the diet (including beverages) (Sn-D). A portion of the samples were wet-ashed, and the liquid samples were analyzed for Sn by the ICP-MS method. For statistical evaluation, χ (2) method and Smirnov's test for extreme value were used. RESULTS: Sn-D in the 108 cases distributed as extremely biased, and could be divided into two groups, i.e., those with <10 µg Sn/day (accounting for 90% of the cases), and those with >10 µg/day (for 10%). Sn-D in the former group was distributed quasi-normally with an AM (median) of 2.9 (2.5) µg/day. The maximum in the latter group was 3012 µg/day. No correlation was detected between Sn-D and Sn in urine (Sn-U). Comparison of the findings with published articles strongly suggested that the high Sn-D was due to consumption of foods (including beverages) preserved in tin-plated cans. No positive confirmation was however possible due to insufficient information on food records. CONCLUSIONS: About 10% of children surveyed had elevated Sn-D (up to 3 mg/day). It was quite possible that high Sn-D was associated with tin-canned food intake.

Food intake survey of kindergarten children in Korea: Part 3 cadmium and lead burden.

OBJECTIVES: This study was initiated to elucidate the extent of dietary exposure of children in Korea to two pollutant metals of cadmium (Cd) and lead (Pb). Possible urban-rural difference was also examined. METHODS: Food duplicate and morning spot urine samples were collected from 108 children in 4 kindergartens (KG) (1 KG in Seoul and 3 KGs in Jeju Island), as reported in a previous publication. The samples were analyzed for Cd and Pb by ICP-MS. RESULTS: Cd and Pb in food duplicate and urine samples were distributed approximately log-normally. Geometric means for Cd and Pb in food duplicate samples were 12.4 and 5.8 µg/day, or 0.58 and 0.27 µg/kg body weight/day, respectively, and the values for Cd and Pb in urine (as observed, i.e., with no correction for urine density) were 0.91 and 1.64 µg/L, respectively. 2.41 and 0.30 µg/day of Cd and Pb (accounting for 19.5 and 5.1%) came from boiled rice, the staple food. The levels of Cd and Pb burden among the children in the present survey were essentially the same with the levels reported for children in Pusan. The reasons for difference in the rank in Cd-D and Cd-U among the 4 KGs need further study. CONCLUSIONS: The observed levels of Cd and Pb exposure were more or less similar to what were reported for children in Pusan. No apparent urban-rural difference could be detected.

Stroke mortality associated with environmental tobacco smoke among never-smoking Japanese women: a prospective cohort study.

OBJECTIVE: This study examined the association of exposure to environmental tobacco smoke (ETS) during adulthood with stroke and its subtypes using data from a large-scale prospective cohort study in Japan. METHODS: The study population included 36,021 never-smoking Japanese women who were enrolled between 1983 and 1985 and were followed-up for 15 years. We used Cox proportional hazard regression models to estimate hazard ratios (HRs) for stroke death associated with ETS exposure at home during adulthood. RESULTS: A total of 906 cases of stroke death were observed during 437,715 person-years of follow-up. Compared with never-smoking women without smoking family members, HRs for stroke mortality among never-smoking women living with smoking family members in all subjects, in those aged 40-79 years, and in those aged ≥ 80 years were 1.14 (95% confidence interval: 0.99-1.31), 1.24 (95% CI: 1.05-1.46), and 0.89 (95% CI: 0.66-1.19), respectively, after adjustment for possible confounders. The risk was most evident for subarachnoid hemorrhage [HR: 1.66 (95% CI: 1.02-2.70) in all subjects]. CONCLUSION: This study suggests that exposure to ETS at home during adulthood is associated with an increased risk of stroke among never-smoking Japanese women.

High iodine intake by preschool children in Miyagi prefecture, Japan.

OBJECTIVES: Standard Tables of Food Composition in Japan 2010 (FCT) remain incomplete for iodine contents. This survey was initiated to develop a method to cope with this shortage and to find daily iodine intake of preschool children in Japan. METHODS: Data were available for one-day food intake for 296 3- to 6-year-old children (the total cases). 128 samples (the selected cases) were analyzed by ICP-MS for iodine (the measured values). Iodine intake was also calculated using FCT assuming that iodine contents in missing items were zero (the calculated values). RESULTS: Measured and calculated values for the selected 125 cases (after exclusion of 3 extreme cases) gave geometric means (GM) of 117.6 and 101.8 µg/day. The measured/calculated ratio in GM, 117.6/101.8 = 1.155, was applied to the calculated values for total 296 cases to estimate iodine intake (the estimated values). GM for the estimated value was 175.2 µg/day and it was 8.93 µg/kg/day after adjustment for body weight for 296 children. There was no significant difference between boys and girls. DISCUSSION: The GM values for both the measured and estimated values (n = 125 pairs) were 117.6 µg/day. The agreement suggested that the factor employed, 1.155, was proper and adequate. Literature survey suggested that values on a body weight basis were comparable between the children and adults in Japan. The levels were higher than levels in east Asian countries. CONCLUSIONS: A correction method was developed for estimation of daily dietary iodine intake. The iodine intake level for preschoolers was comparable to levels for adult population.

High cadmium and low lead exposure of children in Japan.

BACKGROUND: Cadmium (Cd) is a wide-spread environmental pollutant with insidious toxicity to kidneys, and children are considered to be a high-risk group. Lead (Pb) is suspected to induce retardation in mental development in children. Daily foods are an important source of both Cd and Pb exposure for general population. Nevertheless, data on dietary exposure of children to Cd and Pb are still scarce in Japan. OBJECTIVES: This study was initiated to clarify the extent of exposure of children to Cd. Exposure to Pb, another environmental pollutant element, was also studied in combination. METHODS: Twenty-four-hour food duplicates and the first morning urine samples were collected from 296 children (159 boys and 137 girls at the ages of 3-6 years) in 15 kindergartens in Miyagi prefecture on the Pacific coast in north-east Japan; no environmental pollution with Cd has been known in the prefecture. Cd, Pb and iron in food duplicates and Cd in urine were analyzed by inductively coupled plasma-mass spectrometry. α(1)-Microglobulin (α(1)-MG) in urine was measured by the latex method. Log-normal distributions were confirmed for these analytes. RESULTS: The geometric mean (GM) values for dietary intake of Cd and Pb were 11.8 and 2.28 µg/day, or 4.20 and 0.84 µg/kg body weight/week, respectively, for total children studied. No significant difference was detected in dietary Cd and Pb intake between boys and girls of the same age (except for Pb on a µg/day basis at 6 years) as well as of all ages in combination. Trends of increase in Cd and Pb intake were observed parallel to age when calculated on a daily intake basis, but the trends disappeared after correction for body weight. No age-dependent increase was observed in α(1)-MG, despite there was an age-dependent increase in Cd. CONCLUSIONS: The dietary intake of Cd and Pb for children studied were 4.20 and 0.84 µg/kg body weight/week, respectively. International comparison of the present results with values reported in literature suggested that exposure of children in Japan was higher with regard to Cd, and lower regarding Pb, reproducing the observation in adult Japanese populations. For better health of children, efforts may be necessary to reduce high dietary exposure to Cd.

Dietary tin intake and association with canned food consumption in Japanese preschool children.

OBJECTIVES: Dietary intake of tin has seldom been studied in children although they probably have a high intake. This study was initiated to investigate dietary tin intake (Sn-D) of children in Japan. METHODS: In this study, 24-h food duplicate samples were collected from 296 preschool children in Miyagi prefecture, Japan. Sn in the samples were analyzed by inductively coupled-plasma mass spectrometry, after homogenization and wet digestion. RESULTS: Sn-D by the children was low, with 4.2 µg/day as a median. The distribution was however wide, from 0.4 µg/day up to >3 µg/day. Canned foods were the major dietary Sn source, whereas rice contributed essentially little. Sn-D among canned food consumers was 30.2 µg/day as a geometric mean (10.6 µg/day as a median), whereas Sn-D among the non-consumers of canned foods was distributed log-normally, with 3.3 µg/day as a geometric mean (2.5 µg/day as a median). Sn levels in urine did not differ between children who consumed canned foods on the day previous to urine collection and those who did not. The Sn-D was far below the provisional tolerable weekly intake (14 mg/kg body weight/week) set by the 2001 Joint FAO/WHO Expert Committee. Nevertheless, children took more Sn than adults when compared on a body-weight basis. CONCLUSIONS: Canned foods were the major source of dietary Sn intake for preschool children studied. Thus, median Sn-D was higher for the canned food consumers (10.6 µg/day) than for non-consumers of canned foods (2.5 µg/day). Sn-D by canned food-consuming children was, however, substantially lower than the provisional tolerable weekly intake. No difference was detected in Sn levels in urine between canned food-consuming and non-consuming children.

An association between long-term exposure to ambient air pollution and mortality from lung cancer and respiratory diseases in Japan.

BACKGROUND: Evidence for a link between long-term exposure to air pollution and lung cancer is limited to Western populations. In this prospective cohort study, we examined this association in a Japanese population. METHODS: The study comprised 63 520 participants living in 6 areas in 3 Japanese prefectures who were enrolled between 1983 and 1985. Exposure to particulate matter less than 2.5 µm in aerodynamic diameter (PM(2.5)), sulfur dioxide (SO(2)), and nitrogen dioxide (NO(2)) was assessed using data from monitoring stations located in or nearby each area. The Cox proportional hazards model was used to calculate the hazard ratios associated with the average concentrations of these air pollutants. RESULTS: The 10-year average concentrations of PM(2.5), SO(2), and NO(2) before recruitment (1974-1983) were 16.8 to 41.9 µg/m(3), 2.4 to 19.0 ppb, and 1.2 to 33.7 ppb, respectively (inter-area range). During an average follow-up of 8.7 years, there were 6687 deaths, including 518 deaths from lung cancer. The hazard ratios for lung cancer mortality associated with a 10-unit increase in PM(2.5) (µg/m(3)), SO(2) (ppb), and NO(2) (ppb) were 1.24 (95% confidence interval: 1.12-1.37), 1.26 (1.07-1.48), and 1.17 (1.10-1.26), respectively, after adjustment for tobacco smoking and other confounding factors. In addition, a significant increase in risk was observed for male smokers and female never smokers. Respiratory diseases, particularly pneumonia, were also significantly associated with all the air pollutants. CONCLUSIONS: Long-term exposure to air pollution is associated with lung cancer and respiratory diseases in Japan.

Trends in growth status among schoolchildren in Sendai, Japan, 1994-2003: leveling-off of mean body height and weight.

Secular changes in growth have been well documented in various world populations, with secular increase especially noticeable in the developed countries. Accordingly, we have been monitoring the secular changes in growth status among the 6th year children in primary schools (6thPS, 11-12 years old) and 3rd year children in junior high schools (3rdJHS, 14-15 years old) in the city of Sendai since 1934. After World War II, both primary school children and junior high school students showed marked increases in height and weight up to the early 1970s. Acceleration and the subsequent reduction in the degree of acceleration in growth were observed in 1965-1974 and 1975-1984, respectively, and were followed by reacceleration in 1985-1994. The aim of this study was to assess the growth changes among Sendai schoolchildren in 1994-2003. The period between 1994 and 1999 was characterized by positive trends both in height and weight among schoolchildren. However, the degree of the increases in height and weight was diminished between 1999 and 2003. The linear regression analysis revealed the significant increases in mean weight during the 10-year study period in 6thPS boys and 3rdJHS boys and girls. In contrast, there was no significant increase in mean height in any group. These findings suggest the leveling-off of the mean body height and weight among schoolchildren in Sendai at the end of the 20th century. Additional study is needed to examine possible explanations and consequences of these secular trends.

Estimation of dietary intake of cadmium from cadmium in blood or urine in East Asia.

BACKGROUND AND AIM: Cadmium (Cd) is an ubiquitous environmental toxic pollutant. As daily foods are an almost exclusive source of exposure for general populations, it is of public health importance to know the level of dietary intake of cadmium (Cd-D). The purpose of this study is to examine whether Cd in blood (Cd-B) or urine (Cd-U) correlates with Cd-D in East Asia, and in case it is, whether it is possible to estimate Cd-D from Cd-B or Cd-U. It should be added that the measurement of Cd-D is quite hand-consuming in practice. MATERIALS AND METHODS: Literature was retrieved for publication on Cd-B and Cd-U in combination with Cd-D. Twenty three data sets thus obtained for East Asia were subjected to regression analysis to investigate the possibility to estimate Cd-D from Cd-B or Cd-U. RESULTS: In Japan and Korea, large correlation coefficients (p > 0.7) were observed between Cd-B and Cd-D, as well as between Cd-U and Cd-D. In China, the coefficient was >0.7 between Cd-B and Cd-D. Furthermore, correlation was significant for Cd-B and Cd-D, as well as Cd-U and Cd-D, when 19 sets for Japan, Korea and China were combined for analysis. DISCUSSION: Major reasons for successful analysis may be predominant use of women-based data. Women have been less smoking than men in East Asia, and possible confounding effects of smoking on Cd exposure might be minimized. CONCLUSION: Based on significant correlations, Cd-D can be estimated from Cd-B or Cd-U in East Asia.

Large-scale evaluation of the current level of polybrominated diphenyl ethers (PBDEs) in breast milk from 13 regions of Japan.

Polybrominated diphenyl ethers (PBDEs) were measured in 2004 in 105 breast milk samples collected from 13 regions of Japan (Hokkaido, Akita, Miyagi, Tokyo, Gifu, Fukui, Kyoto, Hyogo, Wakayama, Shimane, Yamaguchi, Kochi and Okinawa). Six congeners (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153 and BDE-154) were determined by gas chromatography /mass spectrometry (GC/MS). Total PBDE levels ranged from 0.01 to 23.0 ng/g lipid (geometric mean (GM), 1.34 ng/g lipid). BDE-47 (GM, 0.66 ng/g lipid, 59% of sigmaPBDE) was the most abundant congener present in breast milk and was detected in 99% of the samples. Total PBDE levels were higher in northern Japan than in other regions. We analyzed the effects of occupation, age, smoking status, alcohol consumption and number of deliveries on total PBDE levels. None of these factors were significantly associated with the level of PBDEs. The present study revealed that the current level of exposure to PBDEs in Japan is lower than that in the USA or Sweden. GMs (ng/g lipid) (GSD, geometric standard deviation) and medians (ng/g lipid) of PBDE levels in each district are as follows: Hokkaido 2.70 (1.70), 2.74; Akita 4.49 (2.19), 5.44; Miyagi 1.77 (4.37), 1.11; Tokyo 1.39 (2.09), 1.63, Gifu 2.83 (4.79), 2.23; Fukui 1.05 (2.34), 1.18; Kyoto 1.31 (2.95), 1.33; Hyogo 1.02 (2.69), 0.88; Wakayama 1.33 (3.80), 1.70; Shimane 0.83 (2.51), 0.66; Yamaguchi 1.74 (2.82), 1.76; Kochi 0.50 (2.69), 0.74 and Okinawa 1.91 (2.75), 1.22. This is the first large-scale study of current PBDE levels in breast milk in Japan.

Secular trends and geographical variations in the dietary intake of polybrominated diphenyl ethers (PBDEs) using archived samples from the early 1980s and mid 1990s in Japan.

A retrospective exposure assessment among the general population for polybrominated diphenyl ethers (PBDEs) was conducted using dietary surveys. We analyzed samples of food duplicate portions collected in the early 1980s (1980 survey: N=40) and the mid 1990s (1995 survey: N=39) from female subjects (5 participants from each of 8 sites per survey except for one site) living throughout Japan, from the north (Hokkaido) to the south (Okinawa). The study populations in the 1980 and 1995 surveys were different, but lived in the same communities. We measured four PBDE congeners [2,2',4,4'-tetrabrominated diphenyl ether (tetraBDE): #47; 2,2',4,4',5-pentaBDE: #99; 2,2',4,4',6-pentaBDE: #100; and 2,2',4,4',5,5'-hexaBDE: #153] in the diet. #99 was the most abundant congener in the diet (49% of the total PBDEs), followed by #47 (33%), #100 (12%) and #153 (6%). Regional variations found in the 1980 survey decreased in the 1995 survey. The total daily intake of PBDEs (ng/d) [GM (GSD)] in the 1980 survey [91.4 (4.1)] was not significantly different from that in the 1995 survey [93.8 (3.4)] for the total population, nor did it differ among the sites including Shimane, in which a 20-fold increase in serum concentrations was observed in the same population1). In consideration of the significant increases in the serum concentration, inhalation may be more important than food ingestion as the route of human exposure to PBDEs.

Applicability of food composition tables as a tool to estimate mineral and trace element intake of pre-school children in Japan: a validation study.

Because dietary intakes of some minerals (including trace elements), especially iron (Fe), are insufficient for the needs of the general Japanese population, accurate estimation of mineral intake is important. This capability is especially necessary to preserve the health of Japanese children. Therefore, the current version of food composition tables (FCT) in Japan was evaluated for validity as tools to estimate dietary intake of minerals for children. For this purpose, 24h food duplicate samples were collected from 292 pre-school children in Miyagi prefecture, Japan. From the weights of items and food codes, intakes of nine minerals were estimated taking advantage of the FCT. In parallel, amounts of minerals in each duplicate samples were instrumentally measured by ICP-AES for Ca, Cu, Fe, Mg, Mn, P and Zn, and by flame AAS for K and Na, both after wet-ashing. The distributions of the mineral amounts were essentially normal. The comparison of the FCT-based estimates (E) and instrumental measures (M) showed that the E/M ratio was close to 1 for Ca, K, Mn, P and Zn, suggesting that E may be a surrogate of M for Ca, K, Mn, P and Zn on a group basis. The ratio being larger than 1.2 for Cu, Fe, Mg and Na indicates that a risk of over-estimation exists when E is relied upon in place of M. On an individual basis, significant differences were detected for all 9 minerals suggesting that the use of E as a surrogate for M should be practiced with care for the estimation of mineral intake.

Trends of body mass index distribution in schoolchildren in Sendai, Japan, 1989-2003.

SUMMARY: Accumulating evidence indicates a strong association between obesity and health problems. Childhood obesity increases the risk of adulthood obesity. Although it is reported that the number of obese children in Japan has increased, it is unclear whether the obesity index distribution pattern has changed. To clarify this distribution pattern, we analyzed the changes in the body mass index (BMI) of primary (6th grade, 12 years old) and junior high (3rd year, 15 years old) schoolchildren in the city of Sendai during the period from 1989 to 2003. Our department has accumulated information on the height and body weight of all the schoolchildren in the city of Sendai. BMI was calculated using both the height and body weight data. The change in median BMI for 15 years had a slightly upward trend every year with both gender and school year. Although the BMI distribution showed that there was little or no change over time in the lower (10th and 25th) percentiles, the increases in the 75th and 90th percentiles were more marked than that in the 50th percentile in primary school children. On the other hand, there was only a small increase in BMI in the 3rd year of junior high school. Our results indicated that the changes in BMI distribution were concentrated at the upper end of the distribution in primary school children. The shifts in the value of high percentiles might be due to effect modification of the corresponding exposure by another environmental exposure or genetic predisposition. It is suggested that the factors causing this change influenced only part of this population, and affected individuals might represent a susceptible subpopulation of the exposed children.:

Limited acceptance of globalization in food habits among middle-aged women in Osaka, Japan.

The study was initiated to identify the effects of recent changes in dietary pattern in Japan on nutrient intake. In the large city of Osaka, Japan, 24-h food duplicate samples were collected from 26 middle-aged women, and nutrients in the duplicates were estimated in reference to standard tables of food composition. The subjects took 1844 kcal (7.72 MJ) energy, 67.5 g protein, and 54.5 g lipid (37% from plants) per day. Micro-nutrient intakes were generally sufficient, but NaCl intake tended to be excessive, and the relatively high body mass index (>25 in six cases) suggested a possibility of over-eating. The food composition was rich in rice and fish, being basically of a traditional type. Consumption of bread, an acquired habit, was observed in 65% of the breakfasts but less so in lunch and none in dinner. Thus, the acceptance of bread in place of rice was limited and did not induce substantial alteration in nutrient intakes.

Reduction in estimated vitamin A intake induced by new food composition tables in Japan, where vitamin A is taken mostly from plant foods.

A revised edition of the standard tables of food composition was implemented in Japan in 2005; one of the major revision points is the change of retinol activity equivalents for pro-vitamin A carotenoids. This preliminary analysis was conducted to examine whether the revision affects the estimation of vitamin A intake; and if so, to what extent. Accordingly, a field survey was conducted to collect 24-h duplicates of daily foods of citizens, and 26 adult women volunteered. Application of the procedures in the new and previous standard tables of food composition gave 537 microg retinol activity equivalent and 704 microg retinol equivalence, respectively, for daily vitamin A intake. Thus, the changes in retinol activity equivalents induced substantial reduction (by 24%) in estimation of vitamin A intake among the Japanese population, for whom pro-vitamin A carotenoids in plant foods are the major sources (76%) for vitamin A, and retinol accounts for only 35% (on the retinol activity equivalent basis).

Lung cancer death rates by smoking status: comparison of the Three-Prefecture Cohort study in Japan to the Cancer Prevention Study II in the USA.

Cigarette smoking is an established risk factor for lung cancer. However, the magnitude of the relative risk (RR) on lung cancer mortality in relation to cigarette smoking is reported to be lower in Japan than in Western countries. We investigated whether this discrepancy could be explained by differences in the exposure to cigarettes smoked, by differences in sensitivity to smoking, or by differences in lung cancer mortality among non-smokers. We examined the 10-year follow-up data on 88,153 participants in a Japanese population-based prospective study conducted in three prefectures. Data used as a Western counterpart was retrieved from a published report of the US Cancer Prevention Study (CPS)-II. Although there was a significant increased risk of lung cancer death among current smokers compared with non-smokers, the observed RR in the Three-Prefecture Study were much lower than RR reported in the CPS-II. Lung cancer mortality of our Japanese sample was lower among current smokers and higher among non-smokers regardless of age and sex. Current smokers in our sample had initiated smoking at an older age and smoked fewer cigarettes per day for shorter durations than those in the CPS-II sample. The Poisson regression model (controlling for age, number of cigarettes smoked per day and duration of smoking) showed that male current smokers in our sample had a lower risk of lung cancer compared with those in the CPS-II sample (rate ratio 0.34 [95%CI 0.27-0.43]). These findings might explain why Japanese risks of lung cancer are lower than those observed in Western countries.