We compared the intake of 12 micronutrients as reported on a semiquantitative food frequency questionnaire with corresponding biochemical indicators of nutrient status in a sample of 57 males and 82 females aged 40-83 y. Age-, sex-and energy-adjusted correlation coefficients ranged from near zero for thiamin, vitamin A, and zinc to 0.63 for folate. Correlation coefficients between intake and the biochemical measures were > 0.30 for carotenoids, vitamin D, vitamin E, vitamin B-12, folate, and vitamin C. Differences of 50% or more were observed between extreme quartiles of intake for mean plasma concentrations of folate, vitamin B-12, and vitamin C. Excluding nutrient supplement users generally reduced the correlations. These data demonstrate that food frequency questionnaires can provide valid information on intake for a number of micronutrients.

There were nearly 300,000 PAMV discharges in the United States in 2003 at an annual aggregated hospital cost of > $16 billion, or nearly two thirds of the cost for all of the MV discharges. Despite a higher predicted mortality, patients requiring PAMV had the same likelihood of being discharged alive as those on shorter-term MV. These analyses will help inform health care decision-making and resource planning in the face of an aging population.

Manganese (Mn) is an essential element for humans, animals, and plants and is required for growth, development, and maintenance of health. Mn is present in most tissues of all living organisms and is present naturally in rocks, soil, water, and food. High-dose oral, parenteral, or inhalation exposures are associated with increased tissue Mn levels that may lead to development of adverse neurological, reproductive, or respiratory effects. Manganese-induced clinical neurotoxicity is associated with a motor dysfunction syndrome commonly referred to as manganism. Because Mn is an essential element and absorption and excretion are homeostatically regulated, a reasonable hypothesis is that there should be no adverse effects at low exposures. Therefore, there should be a threshold for exposure, below which adverse effects may occur only rarely, if at all, and the frequency of occurrence of adverse effects may increase with higher exposures above that threshold. Lowest-observed-adverse-effect levels (LOAELs), no-observed-adverse-effect levels (NOAELs), and benchmark dose levels (BMDs) have been derived from studies that were conducted to evaluate subclinical neurotoxicity in human occupational cohorts exposed to Mn. Although there is some uncertainty about the predictive value of the subclinical neuromotor or neurobehavioral effects that were observed in these occupational cohort studies, results of the neurological tests were used in risk assessments to establish guidelines and regulations for ambient air levels of Mn in the environment. A discussion of the uncertainties associated with these tests is provided in this review. The application of safety and uncertainty factors result in guidelines for ambient air levels that are lower than the LOAELs, NOAELs, or BMDs from occupational exposure studies by an order of magnitude, or more. Specific early biomarkers of effect, such as subclinical neurobehavioral or neurological changes or magnetic resonance imaging (MRI) changes, have not been established or validated for Mn, although some studies attempted to correlate certain biomarkers with neurological effects. Pharmacokinetic studies with rodents and monkeys provide valuable information about the absorption, bioavailability, and tissue distribution of various Mn compounds with different solubilities and oxidation states in different age groups. These pharmacokinetic studies showed that rodents and primates maintain stable tissue Mn levels as a result of homeostatic mechanisms that tightly regulate absorption and excretion of ingested Mn and limit tissue uptake at low to moderate levels of inhalation exposure. In addition, physiologically based pharmacokinetic (PBPK) models are being developed to provide for the ability to conduct route-to-route extrapolations, evaluate nasal uptake to the central nervous system (CNS), and determine life-stage differences in Mn pharmacokinetics. Such models will facilitate more rigorous quantitative analysis of the available human pharmacokinetic data for Mn and will be used to identify si...

ObjectiveOsteoarthritis of the hip (OA) is a common degenerative disorder of the joint cartilage that presents a major public health problem worldwide. While intrinsic risk factors (e.g, body mass and morphology) have been identified, external risk factors are not well understood. In this systematic review, the evidence for workload as a risk factor for hip OA is summarized and used to derive recommendations for prevention and further research.MethodsEpidemiological studies on workload or occupation and osteoarthritis of the hip were identified through database and bibliography searches. Using pre-defined quality criteria, 30 studies were selected for critical evaluation; six of these provided quantitative exposure data.ResultsStudy results were too heterogeneous to develop pooled risk estimates by specific work activities. The weight of evidence favors a graded association between long-term exposure to heavy lifting and risk of hip OA. Long-term exposure to standing at work might also increase the risk of hip OA.ConclusionsIt is not possible to estimate a quantitative dose-response relationship between workload and hip OA using existing data, but there is enough evidence available to identify job-related heavy lifting and standing as hazards, and thus to begin developing recommendations for preventing hip OA by limiting the amount and duration of these activities. Future research to identify specific risk factors for work-related hip OA should focus on implementing rigorous study methods with quantitative exposure measures and objective diagnostic criteria.

Occupational exposure limits (OELs) for carbon disulfide vary between 1 and 10 ppm worldwide. They are generally based on health effects observed in viscose industry. Publications after the mid-1970s are reviewed to determine whether there is a scientific justification for an OEL below 10 ppm. The exposure situation in viscose industry is governed by long exposure durations, high exposures in past decades, high peak exposures, former analytical procedures underestimating exposure, and shift work. Three approaches were used to define an OEL based on workplace data: (1) Division of a cumulative exposure index by lifetime exposure duration. This approach ignores the possible existence of a threshold and fails to differentiate between brief high and sustained low exposures. (2) Defining the NOEL/LOEL by mean exposure levels. With a wide range of exposures, effects observed at the mean are driven by high exposures underestimating the true NOEL. (3) Assessment of effects observed at workplaces complying with a predefined exposure limit. Without adverse effects at such a limit this should be the starting point to define the OEL. The most important health effects for carbon disulfide are coronary heart disease, coronary risk factors, retinal angiopathy, color discrimination, effects on peripheral nerves, psychophysiological effects, morphological and other central nervous system (CNS) effects, and fertility and hormonal effects. The data generally support an OEL of 10 ppm. Some uncertainties exist for effects on electrocardiogram (ECG), heart rate, retinal microaneurysms (in Japanese workers), peripheral nerve conduction velocities, some psychophysiological parameters, brain magnetic resonance imaging (MRI; hyperintensive spots), and hearing function. Further investigations on workers under defined long-term exposure conditions might help to come to a final conclusion. Finally, the reproductive capacity of female workers may not be adequately protected at exposures around 10 ppm.