A data-derived safety (uncertainty) factor for the intense sweetener, saccharin

Gestational exposure to phenanthrene induces follicular atresia and endocrine dyscrasia in F1 adult female

Epidemiological investigations and animal studies demonstrate a significantly positive relationship between polycyclic aromatic hydrocarbons (PAHs) exposure and reproductive disorders. However, few researches are focused on the reproductive toxicity of low-molecular-weight PAHs (number of benzene ring ≤ 3) which occupy a large part of PAHs. Phenanthrene (Phe), a typical low-molecular-weight PAH, is one of the most abundant PAHs detected in foods. In the present study, oral treatment with Phe at a human exposure related level during gestation (60 μg/kg body weight every three days, six times in total) induced reproductive disorders in F1 adult female mice: the number of antral follicles (an immature stage of follicular development) were significantly increased, while the maturation of oocytes was inhibited and aggravated follicular atresia was observed; the serum levels of luteinizing hormone (LH), testosterone and estradiol were significantly reduced; the receptor of follicle-stimulating hormone (FSHR) and aromatase in the ovary were significantly upregulated; transcriptome analysis demonstrated that the phosphatidylinositol 3-kinase and protein kinase B (PI3K/Akt) signal pathway was upregulated, and the calcium signal pathway was disturbed, which probably accounts for the exacerbated atresia of the growing follicles and the excessive consumption of follicles. The reproductive toxicity of low-molecular-weight PAHs could not be neglected.

Concepts of the International Programme on Chemical Safety in the Assessment of Risks to Human Health from Exposure to Chemicals

The International Programme on Chemical Safety (IPCS) is a cooperative program of the World Health Organization, the International Labour Organization, and the United Nations Environment Programme. The main objectives of its risk assessment work are to provide, on a global basis, consensus assessments of priority chemicals (including pesticides) and to promote the development, validation, use, and harmonization of sound methodologies for risk assessment. The IPCS provides a number of comprehensive risk assessment documents, the most prominent of which are the Environmental Health Criteria monographs. In addition, evaluations of chemicals in food, air, and drinking water are conducted, and health-and environment-based guidelines for exposure are developed. In deriving guidance values for exposure to chemicals, the risk assessment paradigm of the National Academy of Sciences is followed. The development of guidance values for exposure is based on the calculation of a total intake from all sources. The process involves the identification of the critical effects and the pivotal studies, the derivation of a no (or lowest) observed adverse effect level, the application of (preferably data-derived) uncertainty factors, and the partitioning of the overall tolerable intake among all possible routes of exposure. Work on risk assessment methodologies is directed toward the promotion of scientifically sound approaches to evaluating risks to human health and the environment from exposure to chemicals. Special focus is placed on a project of harmonization of risk assessment methodologies.

Urinary bladder cancer risk factors: a Lebanese case- control study

BACKGROUND

Bladder cancer is the second most incident malignancy among Lebanese men. The purpose of this study was to investigate potential risk factors associated with this observed high incidence.

METHODS

A case-control study (54 cases and 105 hospital-based controls) was conducted in two major hospitals in Beirut. Cases were randomly selected from patients diagnosed in the period of 2002-2008. Controls were conveniently selected from the same settings. Data were collected using interview questionnaire and blood analysis. Exposure data were collected using a structured face-to-face interview questionnaire. Blood samples were collected to determine N-acetyltransferase1 (NAT1) genotype by PCR-RFLP. Analyses revolved around univariate, bivariate and multivariate logistic regression, along with checks for effect modification.

RESULTS

The odds of having bladder cancer among smokers was 1.02 times significantly higher in cases vs. controls. The odds of exposure to occupational diesel or fuel combustion fumes were 4.1 times significantly higher in cases vs controls. The odds of prostate-related morbidity were 5.6 times significantly higher in cases vs controls. Cases and controls showed different clustering patterns of NAT1 alleles. No significant differences between cases and controls were found for consumption of alcohol, coffee, tea, or artificial sweeteners.

CONCLUSIONS

This is the first case-control study investigating bladder cancer risk factors in the Lebanese context. Results confirmed established risk factors in the literature, particularly smoking and occupational exposure to diesel. The herein observed associations should be used to develop appropriate prevention policies and intervention strategies, in order to control this alarming disease in Lebanon.

Urinary bladder cancer risk factors in men: a Spanish case–control study

The rising incidence of urinary bladder cancer is alarming and potential relationships with different risk factors have been postulated. The purpose of this study was to examine the possible relationship between different environmental risk factors and urinary bladder cancer. All men with urinary bladder cancer who were admitted to the Department of Urology of Reina Sofia University Hospital of Cordoba, Spain over 1 year were included in our study. Men were administered an interview questionnaire, which included data on history of known urinary bladder cancer risk factors. Comparisons between men with urinary bladder cancer (cases) and those with nonmalignant urological disease (controls) were made. The study included 74 cases and 89 controls. The variables associated with malignant lesions on univariate analysis were age, smoking and drinking alcohol. Meanwhile, fish, poultry and beef consumption were proved to be protective factors. The risk factors identified by the logistic regression analysis were age, smoking and fluid intake. The independent protective factors on the multivariate analysis were fish and poultry consumptions. Smoking was found to be the principal independent risk factors for urinary bladder cancer. Our results call for further investigation of urinary bladder cancer risk factors; future studies should preferably be performed on large prospective cohorts, to increase their validity.

Hazard assessment of boric acid in toys

Boric acid (H3BO3) has been used in a wide variety of applications--medication, pesticides, and household products. Reports of child poisoning by H3BO3 were common in the clinical literature before 1975. However, a decline in its use as a bacteriostatic agent coupled with increased regulatory control has almost eliminated poisonings by accidental ingestion. Schedule I (Part I, Item 8) of the Hazardous Products Act of Canada, proclaimed in the late 1960s, followed in the wake of concerns about accidental poisoning and prohibits its use in toys. Since that time, scientific knowledge has increased and has led to a reevaluation of the hazard associated with H3BO3. A maximum tolerated dose (MTD) was sought for children in the most susceptible age range, with a view to determine a maximum acceptable concentration (MAC) in toys. The effects of H3BO3 in a variety of exposure scenarios were evaluated. Precedence was given to clinical data in humans, particularly children, since there is no suitable animal model of boric acid intoxication. An extensive search of the pediatric literature was conducted to find a no-observed-adverse-effect level (NOAEL) or a lowest-observed-adverse-effect level (LOAEL). An analysis of the pivotal study to the present assessment resulted in the application of an uncertainty factor of 100 to account for variations in sensitivity among children and for the use of a LOAEL. Based on a pediatric LOAEL of 300 mg/kg body wt, we derived a MTD of 3 mg H3BO3/ kg body wt and a MAC of 9.1 mg H3BO3/g of toy. These results compared favorably with calculations from other human and animal NOAELs/LOAELs.

Setting air quality standards for carcinogens: an alternative to mathematical quantitative risk assessment-discussion paper

It has been accepted in many countries that the regulation of ambient air quality should involve the use of health-based air quality standards. Setting standards for air pollutants which are genotoxic carcinogens presents difficult problems to the regulator, in that the prediction of the effects on health of low levels of exposure is suspected to be inaccurate, and is not currently amenable to either experimental or epidemiological verification. In some countries, techniques of mathematical quantitative risk assessment have been adopted to calculate acceptable levels of exposure to, or the unit risk factors for, genotoxic carcinogens. We regard these approaches as unsatisfactory. An alternative approach, based upon a number of argued premises, a strategy which identifies decision points and the cautious application of uncertainty factors, is described.

Setting air quality standards for carcinogens: an alternative to mathematical quantitative risk assessment--discussion paper

1. It has been accepted in many countries that the regulation of ambient air quality should involve the use of health-based air quality standards. 2. Setting standards for air pollutants which are genotoxic carcinogens presents difficult problems to the regulator, in that the prediction of the effects on health of low levels of exposure is suspected to be inaccurate, and is not presently amenable to either experimental or epidemiological verification. 3. In some countries, techniques of Mathematical Quantitative Risk Assessment (MQRA) have been adopted to calculate acceptable levels of exposure to, or the unit risk factors for, genotoxic carcinogens. We regard these approaches as unsatisfactory. 4. An alternative approach, based upon a number of argued premises, a strategy which identifies decision points and the cautious application of uncertainty factors, is described.

Data-derived safety factors for the evaluation of food additives and environmental contaminants

A safety factor of 100-fold is commonly applied to animal data to derive the acceptable daily intake (ADI) of food additives; other factors have been used in some cases and higher values are used more frequently for determining the tolerable daily intake (TDI) of environmental chemicals. The 100-fold factor is considered to represent the product of a 10-fold factor to allow for species differences between the test animal and humans and a 10-fold factor to allow for inter-individual differences. A scheme is proposed whereby data relevant to the safety assessment of a compound, e.g. species differences in toxicokinetics, can contribute quantitatively to the safety factor and therefore to the ADI or TDI. For this to be possible, it is necessary to subdivide each of the 10-fold factors into two separate factors to allow for differences in toxicokinetics and toxicodynamics. For any compound, data on one particular aspect may be used to derive a specific data-derived factor for that aspect. The overall safety factor will then be calculated as the product of the known data-derived factor(s) and default values for the remaining unknown factors. In this way the derivation of the safety factor would be clearly defined and the potential impact of additional data on other aspects identified. Additional safety factors (over and above the 100-fold or overall data-derived factor) are also proposed to allow for the nature or severity of the toxicity and the adequacy of the database. These factors are consistent with previous evaluations and will allow the logical derivation of factors greater than either 100 or the appropriate data-derived factor. These additional factors will be of greatest value in the derivation of safety factors for the calculation of the TDIs of environmental contaminants but may also be applied if necessary to the safety assessment of food additives. In such cases the rationale and logic for a safety factor in excess of 100 will be clearly defined.