Dietary intake of tin in Japan, and the effects on intake of canned food and beverage consumption.

The study reported herein was initiated to examine dietary tin intake (Sn-D) in Japan to elucidate the possible effects of consumption of canned food (including beverages) on Sn-D, and to compare the intake among regions and between the two sexes in reference to the current provisional tolerable weekly intake and intake in other countries. Urinary tin levels (Sn-U) were also studied. Duplicate diet samples (24 h) together with records of food intake were collected in 1999-2004 from 111 adult residents in four areas of Japan. After exclusion of incomplete samples, 95 valid samples were subjected to determination of tin by inductively coupled plasma mass spectrometry (ICP-MS) after acid digestion. Among the 95 cases, 37 women additionally provided urine samples. Distribution of Sn-D was markedly skewed. Median Sn-D was 5.6 microg day(-1) for total subjects, which was about one-tenth of the values previously reported for the Japanese population; the difference was most probably attributable to the difference in the methods of determination. Consumption of canned foods led to a substantial increase in Sn-D. Thus, the median Sn-D for canned food consumers of 35.7 microg day(-1), was eight-fold higher than the median Sn-D for non-consumers of 4.5 microg day(-1). Sn-U (as corrected for creatinine concentration) distributed log-normally with a geometric mean of 2.0 microg (g cr)(-1). No effect of canned food consumption was evident on Sn-U. When compared internationally, Sn-D for the Japanese population was substantially lower than Sn-D for populations in other industrialized countries.

Gender-related difference, geographical variation and time trend in dietary cadmium intake in Japan.

OBJECTIVES: The present analysis was initiated to examine possible gender-dependency, geographic variation, and time-dependent changes in dietary intake of cadmium (Cd-F) among general populations in Cd-non-polluted areas in Japan. The role of rice as Cd-F source was also within the scope. METHODS: Two databases on Cd and nutritional analyses were re-visited. Both databases were established through collection of 24-h food duplicate portion samples from residents in areas with no known Cd pollution, and contained information on Cd and energy contents in the duplicate portion, together with daily rice consumption, the gender, the age and the location of the residence of each sample donor. The first and the second databases were established through surveys in the years around 1980 on 564 cases and around 1995 on 702 cases, respectively. The two databases were combined for evaluation by multiple regression (MRA) and other analyses. RESULTS: The analyses showed that men tended to take more Cd than women, more clearly so in the 1980 survey than in the 1995 survey. When Cd-F in the 1995 survey was compared with that in the 1980 survey, a substantial decrease was observed, e.g. by 30% (from 37.5 to 26.2 microg/day) in case of women. Cd-F values varied subject to the survey sites in a wide range (e.g. from 20 to 86 microg/day among women in the 1980 survey). In MRA with Cd-F as a dependent variable and survey sites and food intake factors (e.g. rice and energy intakes) as independent variables, the survey sites could explain more than 53% and 35% of total variation in Cd-F in the 1980 and 1995 surveys, respectively. Rice consumption was also influential to Cd-F in both surveys with partial correlation coefficients of 0.36 and 0.21, respectively, the influence being stronger in the 1980 survey than in the 1995 survey. A significant correlation was detected between the 1980 and 1995 survey results both in Cd-F and in rice consumption. CONCLUSION: Geographic and gender-related differences, and time-dependent decrease in dietary Cd intake in Japan were detected through analyses of food duplicate-based databases. The leading role of rice as dietary Cd source was also observed.

Dietary taurine intake and serum taurine levels of women on Jeju Island.

The purpose of this study was to investigate the dietary taurine intake and serum taurine levels of women on Jeju Island in Korea. Sixty six married women aged 43.5 +/- 7.1 volunteered for this study: 34 from the city area and 32 from two fishing-farming areas. Diet samples were collected from the participants; the samples included three meals (breakfast, lunch and supper), including snacks, drinks and whatever else the participants had eaten for 24 hours. Taurine levels in the diet and serum were determined as the dabsyl derivative by HPLC with a Rf-detector. The intake of taurine ranged from 8.4 to 767.6 mg/day and its mean value was 163.9 +/- 150.2 mg/day (mean +/- SD). There was a significant difference between the two groups: 114.9 +/- 78.7 for the women from the city area and 215.9 +/- 187.9 mg/day for the women from the fishing-farming areas (p<0.001). The taurine intake of the total diet, including all snacks and drinks, was 2300 +/- 584 g/day for the city area and 2342 +/- 528 g/day for the fishing-farming areas. The daily protein intake was 58.8 +/- 16.4 g for the women of the city area and 65.5 +/- 17.1 g for the women of the fishing-farming areas. There was a significant correlation between the intake of fish/shellfish and taurine (p=0.001) while there was no correlation between the intake of protein and taurine (p=0.057). The taurine levels in serum ranged from 68.6 to 261.6 micromol/L and the mean value was 169.7 +/- 41.5 micromol/L. There was no significant difference between the women from the city area and the women from the fishing-farming areas in serum taurine levels. The correlations of serum taurine levels with serum retinol levels (p=0.016) and alpha-tocopherol (p=0.014) levels were significant. These results suggest that taurine intake is dependent on the fish/shellfish intake and that taurine may play an important role in the retention of antioxidative nutrients.

Comparison of urinary bromide levels among people in East Asia, and the effects of dietary intakes of cereals and marine products.

Groups of people with no occupational exposure to Br-containing chemicals (29-54 year old, mostly women) in Japan, China and Korea, respectively, offered spot urine samples. Those in China and Korea offered 24 h duplicates of foods of the day. Urine samples were analyzed for Br by ECD-gas chromatography (ECD-GC) after derivatization to methyl bromide, and the Br-U was adjusted for a specific gravity of 1.016. Food intake data were based on national statistics and supplemented by the food duplicate data. Mean Br-U was 5.4 and 6.5 mg/l for Japanese men and women, respectively. Mean levels were in a range of 1.8-2.8 mg/l for four groups of Chinese, and 8-12 mg/l for the four groups of women in Korea. Br-U levels among Korean women were close levels reported for occupational exposure to 1- or 2-bromopropane, or methyl bromide. Regression analyses showed that Br-U levels were influenced by the intake of marine products (such as sea algae, sea fish and shellfish) and fruits, and inversely relate to intakes of cereals and potato.

Estimation of nutrient intake by the new version of Japanese food composition tables in comparison with that by the previous version.

This study was initiated to examine if the revision of the food composition tables from the 4th version to the 5th version has induced any substantial changes in nutrient intake estimation, and if so, in which nutrient item and to what extent. For this purpose, 24-hour duplicates of food samples were collected in 1996 to 1998 from 71 girl university students, together with food menus of the day. The nutrients in the duplicates were estimated by use of the 4th and the 5th version food composition tables in parallel, with supplements of other databases. The results of the estimation with the two databases were compared by Student's paired t-test. Compared with the results with the 4th version, the estimation utilizing the 5th version gave 3 to 8% increases in intakes of major nutrients including energy (except for protein), a 20% increase in vitamin A, and decreases in iron (-13%) and NaCl (-3%), whereas there were only small or essentially no changes in other minerals and vitamins. The largest increment in energy through the re-calculation came from the cereals (especially rice), and it was meats for the increment in lipid intake. The increment in vitamin A with the 5th version is primarily due to the re-evaluation of fruits and vegetables. The present observation suggests that care should be practiced in examining secular trends in nutrition when the basis of estimation is shifted from one database of the 4th version of food composition tables to another of the 5th version. Further study of a larger scale is apparently warranted to confirm the conclusions.

Prevalence of hepatitis B and C virus infection among women in Jeju Island, Republic of Korea.

Hepatitis B and C virus infection prevalence was investigated in the Island of Jeju (formerly Cheju), the Republic of Korea, by means of a small-scale sero-epidemiological survey in 2000. Adult women in the city of Jeju (the provincial capital) and two fishing-farming villages A and B were invited to offer venous blood samples for immunological examination for infection markers of two virus and serum biochemistry for liver function. In practice, 66 married women (33, 16 and 17 women from the city, Village A and Village B, respectively) volunteered. Sera were separated on site and were assayed for HBsAg, anti-HBs, anti-HBc, and anti-HCV positivities and liver function markers including AST, ALT and gamma-GTP. The serum assay showed that the prevalence of HbsAg+ or anti-HCV+ cases was low (5 and 2%, respectively), whereas that of anti-HBs+ and anti-HBc+ cases were high (71 and 62%) so that the over-all HBV positivity was 82%. There were essentially no urban-rural difference or age-dependent changes in the positivity. Comparison with the prevalence reported in literature shows that prevalence of HBsAg+ and anti-HCV+ is in general agreement with the values reported for the populations in general, but HBV+ prevalence might be somewhat higher than the levels reported for the general populations.

Urinary bromide levels probably dependent to intake of foods such as sea algae.

The purpose of the present study is to examine if the bromide (Br) level in urine (Br-U) varies substantially among adult general populations of either sex or of different dietary habits. For this purpose, morning spot urine samples (about 50 per group) were collected from six groups of people, i.e., one group each of men and women in a city in Japan (thus two groups in Japan) and one group each of women in two urban and two rural areas in central and northeast China (four groups in China). The samples were analyzed for Br by ECD-gas chromatography after derivatization to methyl bromide. Br-U essentially followed a normal distribution. Whereas there was only a marginal difference in Br-U between men (7.7 +/- 2.5 mg/L as an arithmetic mean and arithmetic standard deviation) and women (8.1 +/- 2.9 mg/L) in Japan, and no difference between the urban (2.3 +/- 0.8 mg/L) and rural women (2.6 +/- 1.1 mg/L) in China, the difference between Japanese (8.1 +/- 2.9 mg/L) and Chinese women (2.3 +/- 0.8 mg/L for two cities and 2.6 +/- 1.1 mg/L for two villages) was substantial. A literature survey suggested variation in dietary habits, especially that in sea algae intake, is a possible factor affecting the observed difference in Br-U between the two ethnic groups. Contribution of Br in cereals after fumigation with, e.g., methyl bromide, was also thought to be possible. The implication of difference in background Br-U levels is discussed in relation to biological monitoring of exposure to Br-containing industrial chemicals, such as 1- and 2-bromopropane.

Dietary selenium intake of Chinese adult women in the 1990s.

To assess the levels of daily dietary intake of selenium (Se) among the general Chinese population, a series of field surveys were conducted in the 1990s. Samples of 24-h duplicates of foods were collected from 500 participants (300 in 6 cities and 200 from 4 villages). Se levels were determined by microwave digestion followed by inductively coupled plasma-mass spectrometry (ICP-MS), and the measurements were compared with FCT (Food Composition Tables)-based estimates. The average daily intake of Se was 69.2 lg/d (79.9 and 53.1 microg/d in urban and rural areas, respectively) by instrumental determination and 35.1 microg/d (36.7 and 32.7 microg/d) by FCT-based estimation. As the distribution of Se should be uneven within China, the FCT-based estimation is of a limited value and the ICP-MS determination of Se is more accurate and reliable when evaluating the nutritional status of local people. Taking ICP-MS-based values, Se intakes were lower in rural areas than in urban areas, and the intakes of about half of the people in rural areas were less than the Recommended Daily Allowance (RDA) in China of 50 microg/d. The low intake might be resulted from difference in the types of food consumed. Thus, the dietary intake of Se basically meets the recommended RDA in most of urban areas, but insufficiency may be still a nutritional and public health problem in some rural areas.

Cadmium and lead contents in rice and other cereal products in Japan in 1998-2000.

Cereals, especially rice, are a major source of cadmium (Cd) intake for general Japanese populations. In 1998-2000, rice (polished), bread (loaf), noodle and (wheat) flour samples (4113 samples in total) were collected in 63 cities all over Japan, and analyzed for Cd by inductively-coupled plasma mass spectrometry. Another pollutant element of lead (Pb) was determined in parallel. The grand geometric mean for Cd in polished raw (uncooked) rice was 50 ng/g, whereas it was 19 ng/g for flour. The value for Pb was 2-3 ng/g in rice and flour. Calculation for daily Cd intake via rice, taking advantage of the present findings on Cd contents in rice and wheat together with administrative area-specific daily consumptions of rice and wheat showed that Cd via rice is much more than Cd via wheat and that Cd via rice is highest in an area alongside the sea of Japan among the whole country, the observation being in agreement with the results from a previous food duplicate-based field survey.

Nutrient intake of adult women in Jilin Province, China, with special reference to urban-rural differences in nutrition in the Chinese continent.

OBJECTIVES: The objectives of this study were to investigate possible urban-rural differences in food intakes in Jilin province and in continental China as a whole, and to examine possible implications for nutritional status of urban and rural populations. DESIGN: Cross-sectional study. SETTING: Communities. SUBJECTS: In total, 499 adult women in six urban sites and four rural sites, 10 sites in total, including two sites in Jilin province. METHODS: A pair of surveys were conducted in September, 1999, in the provincial capital of Changchun and a farming village in Dehui county, both in Jilin province, in northeast China. Each of 50 adult women per survey site provided a 24 h duplicate food sample and a blood sample, and had an interview on health history including anthropometry and blood pressure measurement. Nutrient intakes were estimated from the food duplicates, using national food composition tables. Results from the two sites were supplemented with data from eight sites where surveys had been conducted following the same protocol, and the pooled material were subjected to analyses for possible urban-rural differences. RESULTS: The Jilin participants consumed daily, on average, about 1600 kcal energy, 44 g protein, and 60 g lipid with a lipid energy ratio (i.e. the ratio of lipid over total nutrients in terms of energy) of 33%. When nutrient intakes were compared between the urban (i.e. Changchun) and rural (Dehui) groups, urban women consumed more energy, protein (especially animal protein) and lipid than rural women. Similar examination of data from six urban and four rural sites, including the present two, showed that adult women in urban areas eat more animal protein and animal fat than their counterparts in villages, and suggested that the observation on urban rural difference in Jilin province can be extrapolated to a nationwide scale. CONCLUSIONS: Urban rural differences in nutrient intakes still persist in 1999 not only in Jilin but in other provinces, typically in the terms of intakes of animal-based foods.

Exposure of women in general populations to lead via food and air in East and Southeast Asia.

BACKGROUND: Despite increasing public concern of the possible health effects of lead (Pb) on general populations, reports on Pb levels in blood (Pb-B) and urine (Pb-B), as well as Pb intake via foods (Pb-F) for many Asian countries are scarce. The present study was initiated to elucidate the extent of non-occupational Pb exposure among general populations in East and Southeast Asia. METHODS: In 1991-1997, peripheral blood, morning spot urine and 24-hour food duplicate samples were collected from 20 to 50 non-smoking adult women in each of four cities in Southeast Asia and five cities in Mainland China, and two cities each in Japan and Korea. The samples were wet-ashed and then analyzed by inductively coupled plasma mass spectrometry for Pb-B, Pb-U and Pb-F. Measures after logarithmic conversion were subjected to ANOVA and regression analysis. RESULTS: Geometric mean values in cities in East and Southeast Asia were in ranges of 32-65 microg/L for Pb-B, 2.1-7.5 microg/g cr for Pb-Ucr, and 7-32 microg/day for Pb-F. The values for a combination of two cities of Tokyo and Kyoto, Japan (38 microg/L for Pb-B and 9.3 microg/day for Pb-F) appeared to be lower than the values for other Asian cities, and the values for all Japan (thus including both urban and rural areas) were even lower (19 microg/L for Pb-B and 7.7 microg/day for Pb-F). Comparison of Pb uptake via respiratory and dietary routes showed that Pb via dietary route accounted for 15% of the total in Manila where Pb in air was high (ca. 650 ng/m(3)), whereas it was 54% in Tokyo+Kyoto where Pb in air was low (ca. 75 ng/m(3)). CONCLUSIONS: When compared internationally, Pb-F and Pb-B in Asia in general are similar to or somewhat higher than the levels in Europe and USA, whereas the levels in Japan are probably lower than the two latter areas. In Asia, Pb-F accounted for 15-54% of all Pb sources, the percentage being variable depending on local conditions especially Pb in atmospheric air.

Urban population exposure to lead and cadmium in east and south-east Asia.

Information is still scarce for many Asian countries on general population exposure to two potentially toxic heavy metals of lead (Pb) and cadmium (Cd). The present review on publications from this study group is intended to provide an overview of the non-occupational exposure to Pb and Cd among general populations in east and south-east Asia. During the period of 1991-1998, surveys were conducted in four cities in south-east Asia, five cities in mainland China, and two cities each in Japan and Korea. Peripheral blood, morning spot urine and 24-h food duplicate samples were collected from 20-50 non-smoking adult women in each survey site. The samples were digested by heating in the presence of mineral acids, and then analyzed by inductively-coupled plasma mass spectrometry for the metals in blood (Pb-B and Cd-B), in urine (Pb-U and Cd-U), and in food duplicate (Pb-F and Cd-F). Measures were subjected to statistical analysis with an assumption of log-normal distribution. Pb-B, Pb-U and Pb-F levels varied substantially among the 11 urban sites; GM distributed in ranges of 32-65 microg/l for Pb-B, 2.1-7.5 microg/g cr (creatinine) for Pb-U, and 7-32 microg/day for Pb-F. The same was also the case for Cd exposure parameters, the distribution ranges being 0.5-1.8 microg/l for Cd-B, 1.2-3.1 microg/g cr for Cd-U, and 5-32 microg/day for Cd-F. It appeared that the exposure to Pb and Cd was highest in Kuala Lumpur, and Tokyo + Kyoto, respectively, and lowest in Tokyo + Kyoto and in Manila. Additional surveys in Japan showed that Pb exposure was even lower in rural areas than in Tokyo + Kyoto. When compared with the values reported in the literature, Pb exposure levels among Asian populations appear to be similar to the levels in Europe and in the United States, whereas Cd exposure seems to be higher in Asia than in Europe. The contribution of the dietary route in Pb absorption was variable and was inversely related to the extent of air pollution, whereas Cd uptake was almost exclusively via the dietary route with little contribution of the respiratory route.

Correlation between urine and blood concentrations, and dietary intake of cadmium and lead among women in the general population of Japan.

OBJECTIVE: To examine whether lead (Pb) in urine and cadmium (Cd) in blood, especially the former, can be used as markers of environmental exposure of general populations to these metals. METHODS: Between 1991 and 1998, spot urine and peripheral blood samples, together with 24 h duplicates of food intake were collected from 607 non-smoking adult women in 30 survey sites (SS) in seven administrative regions all over Japan. Urine, blood and food duplicate samples were analyzed by inductively-coupled plasma spectrometry, for Cd and Pb in urine (Cd-U and Pb-U), in blood (Cd-B and Pb-B) and in food duplicates (Cd-F and Pb-F). Correlation between the measurements was examined by regression analysis. RESULTS: The Cd-B correlated closely with Cd-U, and both Cd-B and Cd-U with Cd-F, on an individual basis (n = 607), on an SS basis (n = 30) and on a regional basis (n = 7). The Pb-U however did not correlate with Pb-B on a regional basis although they correlated with each other when analyzed on an individual as well as SS basis. Moreover, the correlation coefficients between Pb-U and Pb-B were much smaller than those between Cd-U and Cd-B. Neither Pb-U nor Pb-B showed significant correlation with Pb-F on any levels of statistical analysis. CONCLUSIONS: Both Cd-B and Cd-U can be employed as biomarkers of environmental Cd exposure. The reliability of Pb-U for use in place of Pb-B appeared to be small.

Nutrient intake of working women in Bangkok, Thailand, as studied by total food duplicate method.

OBJECTIVES: To establish a general view of food habits in Thailand, and to make a quantitative assessment of rice dependency of Thai people. DESIGN: Cross-sectional study. SETTING: Community. SUBJECTS: 52 non-smoking and non-habitually drinking adult women in Bangkok participated in the study. METHODS: The participants offered 24 h food duplicates and peripheral blood samples, and underwent clinical examination including anthropometry. The duplicates were subjected to nutritional evaluation taking advantage of the Thai food composition tables (FCTs), and analyzed for eight nutrient elements by inductively coupled plasma mass spectrometry (ICP-MS). RESULTS: The participants took 1630 kcal from 55 g protein (63% from animal sources), 57 g lipid (mostly from vegetable oil), and 224 g carbohydrate (60% from rice) daily. Nutrient intake at lunch was as large as that at dinner. About a half of the women had insufficient energy intake (ie <80% RDA) whereas 4% had an excess (>120%). Protein intake was sufficient in most cases, whereas lipid intake was in excess in more than a half of the women. Ca, Fe, Mg, Zn and possibly P intakes were below the RDA values in many participants. FCT-based estimates agreed well with the ICP-MS measures in cases of Fe and Ca but tended to be greater than the measures by 50% with regard to P. CONCLUSIONS: Lunch as substantial as dinner for Thai urbanites. There was a marked dependency on rice as an energy source. Whereas protein intake is generally sufficient, the intake of Ca (and to a lesser extent Fe) was insufficient in a majority of the study participants. SPONSORSHIP: Dai-ichi Mutual Life Insurance, Japan; the Ministry of Health and Welfare, the government of Japan.

Normal liver function in women in the general Japanese population subjected to environmental exposure to cadmium at various levels.

OBJECTIVES: Whereas it is well established that environmental exposure to cadmium (Cd) may induce kidney dysfunction, less attention has been paid to the possible disturbance of liver function by Cd exposure. The possibility that liver function is adversely affected by current levels of environmental exposure to Cd as investigated in women in the general population in Japan, where the background level of exposure to Cd is known to be high. METHODS: From 1991 to 1997, 24-h food duplicate, peripheral blood and morning spot urine samples were collected from 607 non-smoking and non-habitually drinking women (age range 19-78 years) at 30 survey sites (with no known environmental pollution from heavy metals) throughout Japan. Liver function parameters in serum were examined by conventional methods. After wet-ashing, the food duplicate, blood and urine samples were analyzed for Cd intake via food (Cd-F), Cd in blood (Cd-B), and Cd in urine (Cd-U) by inductively-coupled plasma mass spectrometry. RESULTS: The geometric mean values for Cd-F, Cd-B, and Cd-U were 24.7 (27.1) microg/day, 1.76 (2.07) microg/l, and 3.94 (4.61) microg/g creatinine (values in parentheses for 41- to 60-year-old women), respectively. It as found that the three parameters of ALP, ALT, and AST activity were positively and significantly related to the age of the subjects (whereas no association as detected in cases of gamma-GTP, LAP, and albumin). Accordingly, a further analysis as made with 367 women selected by age (41-60 years; about 60% of the total population). Essentially, no Cd dose-dependent changes in liver function parameters were observed in the selected population of this narrower age range. CONCLUSIONS: Overall, it seemed prudent to conclude that liver function as not disturbed by the current environmental exposure to Cd in Japan.

Further reduction in lead exposure in women in general populations in Japan in the 1990s, and comparison with levels in east and south-east Asia.

OBJECTIVE: The objective of the study was to elucidate the current level of environmental lead (Pb) exposure of women in general population in Japan, where the use of organic Pb in automobile gasoline was phased out from 1973 to reach a zero level early in the 1980s. METHODS: A survey was conducted in 27 sites throughout Japan from 1991 to 1997. Five hundred and eighty-eight non-smoking women from the sites offered 24-h food duplicate, peripheral blood, and spot urine samples. Pb in food duplicates (Pb-F), blood (Pb-B), and urine (Pb-U) were analyzed by inductively-coupled plasma mass spectrometry. The results of Pb-F and Pb-B were compared with observations from a study conducted from 1977 to 1981 on 339 women at the same sites. Log-normal distribution was assumed for the evaluation of the results. RESULTS: Geometric means (GMs) of Pb-F, Pb-B, and Pb-U in the 1991-1997 study were 9.0 microg/day, 20.2 microg/l, and 2.18 microg/g creatinine, respectively. The values for Pb-F and Pb-B were substantially lower than the values (32.8 microg/day for Pb-F and 31.7 microg/l for Pb-B) obtained in the 1977-1981 study, which were already low when compared internationally. Cd-U values in the period from 1991 to 1997 also appeared to be among the lowest in the world. Analysis for time-dependent changes in Pb-U was, however, not possible at the time of this study because no values were available for the period from 1977 to 1981. CONCLUSIONS: Substantial reductions from 1977-1981 levels in environmental Pb exposure were observed among the study populations in Japan. Current exposure levels appear to be lower than those in other parts of Asia, the USA, and Europe.

Correlation between concentration in urine and in blood of cadmium and lead among women in Asia.

The objectives of the present study are to examine if there exists a quantitative relationship between lead in urine (Pb-U) and that in blood (Pb-B), and also between cadmium in urine (Cd-U) and that in blood (Cd-B) among the general populations who are environmentally (and not occupationally) exposed to these elements at various levels. For this purpose, peripheral blood and morning spot urine samples were collected in 1991-1998 from approximately 50 non-smoking adult women each in four cities in south-east Asia and five cities in mainland China, and two cities each in Japan and Korea. The samples were wet-ashed and then analyzed by inductively-coupled plasma mass spectrometry for Pb-B, Cd-B, Pb-U and Cd-U. Measured values were subjected to analysis to detect possible correlation between the pairs of parameters. A significant correlation between Pb-B and Pb-U was observed when the intensity of Pb exposure (as expressed by Pb-B) was relatively high so that the correlation was significant in all cases studied when Pb-B level was, e.g. 50 microg/l or above. It was also observed that the correlation between Cd-B and Cd-U was significant when Cd-B was, e.g. > 1 microg/l. Thus, it is possible to deduce that, in environmental health, Pb-B and Cd-U levels can be estimated on a group basis from Pb-U and Cd-B, respectively, when Pb and Cd exposure levels are relatively high, e.g. with Pb-B and Cd-B of > 50 microg/l and > 1 microg/l.

Background lead and cadmium exposure of adult women in Xian City and two farming villages in Shaanxi Province, China.

The objectives of the present study are: (a) to clarify the current levels of environmental exposure to lead (Pb) and cadmium (Cd) in Shaanxi Province in China in comparison with levels in other parts of mainland China; (b) to examine if there is any urban-rural difference in Pb and Cd exposure; and (c) to quantify the role of cereals as the dietary source of environmental exposure to these metals. For this purpose, triplet surveys on lead and cadmium exposure were conducted in the provincial capital of Xian and two farming villages A and B in Shaanxi Province, China in 1997. The grand geometric mean for lead (Pb) intake via foods (Pb-F), Pb in blood (Pb-B) and Pb in urine as corrected for creatinine concentration (Pb-Ucr) were 30 micrograms/day, 33 micrograms/l and 5 micrograms/g creatinine, respectively, with significant differences among the survey sites, e.g. Pb-B being higher in Xian (43 micrograms/l) than in the two villages (38 and 22 micrograms/l). The counterpart values for cadmium (Cd) intake via foods (Cd-F), Cd in blood (Cd-B) and Cd in urine (Cd-Ucr) were 6.1 micrograms/day, 0.46 microgram/l and 2.8 micrograms/g creatinine, respectively, with no substantial inter-survey site difference. Thus, it was possible to conclude that, from comparison with the values reported in 1990s literature, the exposure of Shaanxi people to Pb and Cd is no higher than, and even possibly lower than, the levels reported for people in other parts of mainland China. The exposure to Cd was almost exclusively from foods, whereas the exposure to air-borne Pb was large enough in Xian to explain higher Pb-B and Pb-Ucr than the level in Village B despite lower Pb-F in Xian than in Village B. Cereals (wheat, rice, maize and foxtail millet) contributed 26 and 84% of dietary Pb and Cd intake, respectively.

Possible effects of environmental cadmium exposure on kidney function in the Japanese general population.

OBJECTIVES: To examine whether the current level of environmental exposure to cadmium (Cd) is associated with kidney dysfunction among general populations in Japan. METHODS: A nationwide survey was conducted in Japan from 1991 to 1997 at 30 survey sites (with no known environmental heavy metal pollution), by the collection of 24-h food-duplicate samples, peripheral blood specimens and morning spot urine samples. In practice, 607 non-smoking adult women provided these samples. After being wet-ashed, the samples were analyzed for Cd in food duplicates (Cd-F), in blood (Cd-B) and urine (Cd-U) by inductively-coupled plasma mass spectrometry (ICP-MS). Urine samples were also analyzed for alpha 1-microglobulin (alpha 1-MG), beta 2-microglobulin (beta 2-MG) and retinol-binding protein (RBP), creatinine (cr) and specific gravity. Possible tubular dysfunction in association with Cd exposure was examined by simple, multiple and logistic regression analyses, and comparison among three different Cd-dose groups. To minimize the confounding effects of aging, 367 women from 41 to 60 years old were selected and subjected to the same statistical analyses. RESULTS: The analysis of a whole population of 607 women showed that alpha 1-MG and possibly beta 2-MG increased as a function of Cd-F, Cd-B and Cd-U. When the analysis was repeated with the selected population of 367 women aged 41-60, the Cd dose-dependent changes in alpha 1-MG and beta 2-MG became less evident. The distribution of the selected population with alpha 1-MG above two low cut-off values of > 4.9 and > 8.4 mg/g cr or with beta 2-MG above the lowest cut-off value of > 400 micrograms/g cr, was biased toward the group with higher Cd-Ucr, but such bias was not significant for both alpha 1-MG and beta 2-MG when higher cut-off values were employed. No bias was detected with RBP. Logistic regression analysis with alpha 1-MG, beta 2-MG and RBP (with cut-off values given above) in combination with age, Cd-F, Cd-B and Cd-Ucr gave essentially the same results. CONCLUSIONS: The evidence for kidney dysfunction was of borderline significance in the present study population for which geometric mean Cd-F, Cd-B and Cd-U were 24.7 micrograms/day, 1.76 micrograms/l, and 3.94 micrograms/g cr, respectively. The findings might suggest at the same time that the safety margin is small for the Japanese general population regarding environmental Cd exposure.

Cadmium exposure of women in general populations in Japan during 1991-1997 compared with 1977-1981.

OBJECTIVES: The Japanese people are known to have high environmental exposure to cadmium (Cd). The present survey was initiated to elucidate possible changes in the intensity of Cd exposure to the population by comparison of the present exposure level with the situation some 15 years ago. METHODS: During 1991-1997, 24-h food-duplicate samples, peripheral blood specimens and morning spot urine samples were collected from 588 non smoking women from 27 survey sites in six regions, where food-duplicate and blood samples had also been obtained during 1977-1981 from 399 women. The samples were wet-ashed (after homogenization in the case of food-duplicates), and Cd in the wet-ashed samples was analyzed by inductively-coupled plasma mass spectrometry for Cd intake via foods (Cd-F), Cd concentration in blood (Cd-B) and Cd concentration in urine (Cd-U). The Cd-F and Cd-B were compared with the Cd-F and Cd-B obtained at the same sites in the 1977-1981 survey. RESULTS: The exposure levels during 1991-1997 were such that Cd-F, Cd-B and Cd-Ucr (Cd-U after correction for creatinine concentration) were 25.5 micrograms/day, 1.90 micrograms/l and 4.39 micrograms/g creatinine. Comparison with the 1977-1981 survey results (i.e., 37.5 micrograms/day for Cd-F and 3.47 micrograms/l for Cd-B) showed that there were significant reductions (by 32 and 45%) in both parameters respectively during the last 15 years. The dietary route was an almost exclusive (i.e., 99% of the sum of dietary and respiratory uptake) route of Cd uptake, of which Cd in rice (11.7 micrograms/day) contributed about 40% of the total dietary intake. When compared among survey sites, inter-site variation in dietary Cd intake was primarily due to differences in the intake through boiled rice. Despite the recent reduction in Cd exposure, the current exposure level for Japanese people is still higher than the levels among other rice-dependent populations in Asia as well as in other parts of the world. Comparison was made between the present findings in general populations and observations among known Cd-pollution cases in Japan. CONCLUSIONS: Dietary uptake is an almost exclusive route of Cd exposure in the general Japanese population. Boiled rice is a strong determinant of variation in dietary Cd intake. Whereas there was a substantial reduction in Cd exposure among Japanese populations in the last 15 years, the current level is still high when compared internationally.