Tofu consumption and blood lead levels in young Chinese adults.

Tofu is a commonly consumed food in China. Tofu may interfere with lead absorption and retention because of its high calcium content. In this observational study, the authors examined whether dietary tofu intake was associated with blood lead levels among young adults in Shenyang, China. The analyses included 605 men and 550 women who completed baseline questionnaires and had blood lead measurements taken in 1996-1998 as part of a prospective cohort study on reproductive health. Mean blood lead levels were 13.2 microg/dl in men and 10.1 microg/dl in women. Blood lead levels were negatively associated with tofu intake in both genders. A linear trend test showed a 3.7% (0.5-microg/dl) decrease in blood lead level with each higher category of tofu intake (p = 0.003). The highest tofu intake group (> or =750 g/week) had blood lead levels 11.3% lower (95% confidence interval: 4.1, 18.0) than those of the lowest tofu intake group (<250 g/week). In all regression models, data were adjusted for gender, age, height, body mass index, district, cigarette smoking, alcohol drinking, education, occupation, use of vitamin supplements, season, and dietary intake of meat, fish, vegetables, eggs, and milk. In conclusion, the authors found a significant inverse dose-response relation between tofu consumption and blood lead levels in this Chinese population.

Petrochemical exposure and menstrual disturbances.

BACKGROUND: An exploratory, cross-sectional retrospective study was conducted to examine the effects of benzene exposure on menstrual problems. METHODS: The study was based on a survey administered to over 3,000 women who worked in a large petrochemical company in Beijing, China. An abnormal menstrual cycle length (AMCL), defined as an average menstrual cycle length of greater than 35 days or less than 21 days, is the major outcome of interest. RESULTS: After 7 years of benzene exposure, the adjusted odds ratio of having AMCL for each additional 5 years of exposure was 1.71 (95% CI 1.27-2.31). Feeling stressed at work was also an important predictor. CONCLUSIONS: This study suggests a significant association of benzene exposure and perceived stress with menstrual disturbance. A prospective study is needed to confirm this finding.

Pulmonary responses to oil fly ash particles in the rat differ by virtue of their specific soluble metals.

Occupational exposure to residual oil fly ash (ROFA) particulate has been associated with adverse respiratory health effects in humans. We hypothesized that ROFA collected at different sites within an oil burning power plant, by virtue of its differing metal and sulfate composition, will induce differential lung injury. Ten ROFA samples collected at various sites within a power plant were analyzed for water- and 1.0 M HCl-leachable arsenic (As), beryllium (Be), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), vanadium (V), zinc (Zn), and sulfur by inductively coupled plasma-atomic emission spectroscopy. All ROFA samples contained variable amounts of leachable (water-extractable) and 1.0 M HCl-extractable Fe, V, and/or Ni. All other metals, except Zn (ROFA No. 1 contained 3.43 and No. 3, 6.35 micrograms/mg Zn), were present in negligible quantities (< 1.0 microgram/mg) in the water extract. In vivo pulmonary injury from exposure to whole saline suspensions of these ROFA was evaluated. Male, SD rats (60 days old) were intratracheally instilled with either saline or saline suspension of whole ROFA (< 3.0 mass median aerodynamic diameter) at three concentrations (0.833, 3.33, or 8.33 mg/kg). After 24 h, lungs were lavaged and bronchoalveolar lavage fluid (BALF) was analyzed for cellular influx and protein content as well as lactate dehydrogenase (LDH) and N-acetyl glucosaminidase (NAG) activity and total hemoglobin as indicators of lung injury. ROFA-induced increases in BALF protein and LDH, but not neutrophilic inflammation, were associated with its water-leachable total metal, Ni, Fe, and sulfate content. However, the neutrophilic response following ROFA exposure was positively correlated with its water-leachable V content. Modest lung injury was observed with the ROFA samples which contained the smallest amounts of water-leachable metals. The ability of ROFA to induce oxidative burst in alveolar macrophage (AM) was determined in vitro using a chemiluminescence (CL) assay. AM CL signals in vitro were greatest with ROFA containing primarily soluble V and were less with ROFA containing Ni plus V. In summary, ROFA-induced in vivo acute pulmonary inflammation appears to be associated with its water-leachable V content; however, protein leakage appears to be associated with its water-leachable Ni content. ROFA-induced in vitro activation of AM was highest with ROFA containing leachable V but not with Ni plus V, suggesting that the potency and the mechanism of pulmonary injury will differ between emissions containing V and Ni.

Genotoxicity to human cells induced by air particulates isolated during the Kuwait oil fires.

In an effort to examine the potential of exposure to soot from the 1991 oil fires in the Kuwait desert for inducing genetic effects we studied the in vitro genotoxicity of this material. Air particulates isolated near the Kuwait oil fires were studied using three assays. Dose-dependent increases were observed for both sister chromatid exchanges in human peripheral blood lymphocytes and mutation at the hprt locus in the metabolically competent human lymphoblast cell line AHH-1. Similar magnitudes of response were seen using these two assays when testing a standard air particulate sample which had been isolated from the Washington, DC, area. Using the 32P-postlabeling assay, no increase in DNA adduct formation was observed in AHH-1 cells treated with particulates isolated from sampling in Kuwait.

The presence of urinary cellular sediment and albuminuria in newspaper pressworkers exposed to solvents.

To investigate the relationship between exposure to organic solvents and the presence of increased urinary cellular sediment, we conducted a cross-sectional study of 215 newspaper pressroom workers who were exposed to solvent and lubricant mixtures. Thirty-two compositors were surveyed as referents. Industrial hygiene measurements showed low-level airborne exposures to organic solvents (primarily naphthas) and minimal airborne exposure to glycol ethers. There was a high prevalence of solvent-related dermatitis indicating there was significant dermal exposure to these substances. Pressworkers were exposed to solvent mixtures that were associated with dose-related increases in leukocyturia alone or in urinary cellular sediment (erythrocyturia and/or leukocyturia). The presence of urinary cellular sediment was associated with increasing frequency of use of five particular organic solvent mixtures. These results suggest that the increase in urinary cellular sediment may be due, at least in part, to the effects of solvents on the kidney. Consistent with this hypothesis, 16% of pressmen and no compositors were found to have primarily low-grade albuminuria detectable by dipstick. Workers with urinary cellular sediment were significantly more likely to have detectable albuminuria. Albuminuria was more likely to occur with increased frequency of use of four particular solvent mixtures. The presence of urinary cellular sediment was less likely to occur with occasional use of analgesics suggesting a possible etiologic role for acute or chronic urinary tract inflammation.