Documents neurological effects 18 results

"Objective
This study aimed to investigate sleep and circadian phase in the relationships between neurobehavioral performance and the number of consecutive shifts worked.
Methods
Thirty-four shift workers [20 men, mean age 31.8 (SD 10.9) years] worked 2–7 consecutive night shifts immediately prior to a laboratory-based, simulated night shift. For 7 days prior, participants worked their usual shift sequence, and sleep was assessed with logs and actigraphy. Participants completed a 10-minute auditory psychomotor vigilance task (PVT) at the start (~21:00 hours) and end (~07:00 hours) of the simulated night shift. Mean reaction times (RT), number of lapses and RT distribution was compared between those who worked 2–3 consecutive night shifts versus those who worked 4–7 shifts.
Results
Following 4–7 shifts, night shift workers had significantly longer mean RT at the start and end of shift, compared to those who worked 2–3 shifts. The slowest and fastest 10% RT were significantly slower at the start, but not end, of shift among participants who worked 4–7 nights. Those working 4–7 nights also demonstrated a broader RT distribution at the start and end of shift and had significantly slower RT based on cumulative distribution analysis (5th, 25th, 50th, 75th percentiles at the start of shift; 75th percentile at the end of shift). No group differences in sleep parameters were found for 7 days and 24 hours prior to the simulated night shift.
Conclusion
A greater number of consecutive night shifts has a negative impact on neurobehavioral performance, likely due to cognitive slowing."

"utdoor air pollution, largely from fossil fuel burning, is a major cause of morbidity and mortality in the United States, costing billions of dollars every year in health care and loss of productivity. The developing fetus and young child are especially vulnerable to neurotoxicants, such as polycyclic aromatic hydrocarbons (PAH) released to ambient air by combustion of fossil fuel and other organic material. Low-income populations are disproportionately exposed to air pollution. On the basis of the results of a prospective cohort study in a low-income population in New York City (NYC) that found a significant inverse association between child IQ and prenatal exposure to airborne PAH, we estimated the increase in IQ and related lifetime earnings in a low-income urban population as a result of a hypothesized modest reduction of ambient PAH concentrations in NYC of 0.25?ng/m3. For reference, the current estimated annual mean PAH concentration is ~1?ng/m3. Restricting to NYC Medicaid births and using a 5 per cent discount rate, we estimated the gain in lifetime earnings due to IQ increase for a single year cohort to be US$215 million (best estimate). Using much more conservative assumptions, the estimate was $43 million. This analysis suggests that a modest reduction in ambient concentrations of PAH is associated with substantial economic benefits to children."

"Objectives This study examined onset time for reported vascular and neurological symptoms in relation to the vibration load in a group of workers exposed to vibration.Methods Information on the self-stated year for the first occurrence of symptoms was collected by means of questionnaires. During interviews data were obtained on self-stated estimations of daily exposure time, type of tool, and number of months or years with different exposures. The estimations of the vibration magnitudes of exposure were based on conducted measurements. From these data, the individual vibration exposure at the time of onset of symptoms was calculated.Results The incidence was 25.6 and 32.9 per 1000 exposure years for vascular and neurological symptoms, respectively, in the group of workers. The first onset of symptoms appeared after an average of 12 years of exposure. For the workers, the symptoms of vascular or neurological disorders started after about the same number of exposure years. The calculated accumulated acceleration correlated best with the onset time of symptoms.Conclusions It was concluded that, since the workers' exposure to vibration was below the action level established in the European vibration directive, the results suggest that the action level is not a safe level for avoiding vascular and neurological symptoms."

Evaluates over 700 studies in an effort to determine the risks to human health and the environment posed by carbaryl. This broad spectrum contact and ingestion insecticide has been widely used for over 30 years to control various insect pests on food and fibre crops, trees, and ornamentals. Carbaryl is used to control flies, mosquitos, ticks, and lice in cattle, poultry, and pets, and to treat body louse infestation in humans. The compound is currently processed by more than 290 formulators into over 1,500 different registered products.

Abundant data support the conclusion that carbaryl is rapidly degraded, does not persist in the environment, does not readily leach into ground water, and should not cause harmful short-term effects on the ecosystem. Carbaryl has low acute toxicity for birds, but very high toxicity for honey-bees and earthworms, supporting the conclusion that carbaryl should not be applied to crops during flowering.

The most extensive section reviews the large number of experiments designed to assess the toxic effects of carbaryl and elucidate its mechanisms of action. These studies, supported by limited human data, confirm that carbaryl poses no risk of inducing genetic changes in human tissues, that toxic effects are consistent with the signs and symptoms of cholinesterase inhibition, and that signs of intoxication develop quickly, appear well before a dangerous dose is absorbed, and disappear rapidly when exposure ends. Tthe book concludes that, under normal conditions of use, carbaryl poses a low risk to the environment and to the health of the general population. Levels detected in food and drinking-water are far below the acceptable daily intake and thus unlikely to endanger health. When reasonable safety precautions and measures for personal protection are enforced, occupational exposure to carbaryl during manufacture, formulation and application will not create health hazards for workers.

"The developing brain is remarkably malleable as neural circuits are formed and these circuits are strongly dependent on hormones for their development. For those reasons, the brain is very vulnerable to the effects of endocrine-disrupting chemicals (EDCs) during critical periods of development. This review focuses on three ubiquitous endocrine disruptors that are known to disrupt the thyroid function and are associated with neurobehavioral deficits: polychlorinated biphenyls, polybrominated diphenyl ethers, and bisphenol A. The human and rodent data suggesting effects of those EDCs on memory, cognition, and social behavior are discussed. Their mechanisms of action go beyond relative hypothyroidism with effects on neurotransmitter release and calcium signaling."

"While access to electricity affects health positively, combustion of coal in power plants causes well-documented adverse health effects. We review respiratory, cardiovascular, reproductive, and neurologic health outcomes associated with exposure to coal-fired power plant emissions. We also discuss population-level health effects of coal combustion and its role in climate change. Our review of scientific studies suggests that those we present here can be used to inform energy policy."

The neurobehavioral characteristics of painters exposed to solvents were compared to those of unexposed sheetmetal workers. The data were obtained from screening programs which consisted of a health and neurobehavioral evaluation as well as a health and work history related questionnaire. Neurobehavioral evaluation included simple reaction time, visual digit span, symbol/digit substitution, pattern memory, vocabulary, and mood tests. Three exposure indices were assembled for the painters. The first index estimated the amount of time a painter worked with oil or solvent based paints. The second index estimated the amount of solvent exposure and respirator use, while incorporating the application method used. The third index estimated the application rate in addition to the variables addressed in the second index. Painters performed significantly worse than sheetmetal workers in symbol/digit substitution, pattern memory, and vocabulary tests. When the vocabulary and symbol/digit substitution scores were treated as covariates, the significant difference between the pattern memory scores of the painters and sheetmetal workers was no longer observed. The three most commonly used solvents in the painting industry were mineral-spirits (64475850), xylene (1330207), and naphtha (8030306). The second and third indices were highly correlated, with a coefficient of 0.88. With increasing solvent exposure, correct answers on the vocabulary and pattern memory tests decreased significantly, while response latency on the symbol/digit substitution test increased significantly. Regarding the second and third indices, increasing exposure was significantly correlated with increasing response latency on the symbol/digit substitution and pattern memory tests and decreasing scores on the vocabulary, pattern memory, and backward digit span tests. The increased exposures calculated by the third index were also significantly related to increased lead (7439921) levels, and increased renal and hematological health problems. The authors conclude that solvent exposure in painters is related to poor neurobehavioral performance.

Evaluates the risks to human health and the environment posed by exposure to polybrom-inated biphenyls (PBBs). These chemicals were introduced as flame retardants in the early 1970s and used in the manufacture of small appliances and in automotive applications, coatings, lacquers, and polyurethane foam. Research on these chemicals has been especially intense following a 1973 poisoning disaster, in Michigan, USA, caused when the flame retardant FireMaster® was inadvertently confused with a magnesium oxide-based cattle feed supplement. The flame retardant was added to animal feed and widely distributed to farms within the state. The ensuing contamination of farm animals resulted in the destruction of tens of thousands of cattle, pigs, and sheep, and more than a million chickens. Since the cause of contamination remained undetected for almost a year, thousands of farmers and other consumers were exposed to PBBs through the consumption of contaminated meat, eggs, and dairy products.

Although production of PBBs has been halted or severely restricted in many parts of the world, these chemicals remain of enduring concern due to their extreme persistence in the environment, their concentration in the food chain, their marked tendency to bioaccumulate in living organisms, including humans, and the potential for adverse health effects following long-term exposure to very low levels.

The most extensive section assesses the large number of studies conducted in experimental animals and in vitro test systems. Toxic effects demonstrated in numerous studies and in many species include wasting syndrome, thymus atrophy, hepatotoxicity, liver cancer, skin disorders, and adverse effects on reproduction, including fetal wastage and decreased viability of offspring. Citing overwhelming evidence, the report concludes that commercial use of these compounds should cease.