Towards developing a Core Outcome Set for malnutrition intervention studies in older adults: a scoping review to identify frequently used research outcomes.

PURPOSE: To conduct a scoping review to provide a systematic overview of outcomes used in nutritional intervention studies focused on the treatment of protein-energy malnutrition in older adults. METHODS: A systematic search of four electronic databases (Medline, EMBASE, CINAHL and Cochrane Central Register of Controlled Trials (CENTRAL) was performed to retrieve randomized controlled trials (RCTs), published until March 9, 2020, that evaluated the effect of nutritional interventions to treat protein-energy malnutrition in older adults and those at risk for malnutrition. Two authors screened titles, abstracts and full texts independently. One author extracted data that were cross-checked by another author. RESULTS: Sixty-three articles reporting 60 RCTs were identified. Most frequently used outcomes included body weight/body mass index (75.0% of RCTs), dietary intake (61.7%), functional limitations (48.3%), handgrip strength (46.7%), and body circumference (40.0%). The frequencies differed by setting (community, hospital and long-term care). For some outcomes there was a preferred assessment method (e.g., Barthel index for functional limitations), while for other outcomes (e.g., functional performance) a much greater variation was observed. CONCLUSION: A large variation in outcomes, not only across but also within settings, was identified in nutritional intervention studies in malnourished older adults and those at risk. Furthermore, for many outcomes there was a large variation in the used assessment method. These results highlight the need for developing a Core Outcome Set for malnutrition intervention studies in older adults to facilitate future meta-analyses that may enhance our understanding on the effectiveness of treatment.

Effects of an individualised nutritional intervention to tackle malnutrition in nursing homes: a pre-post study.

PURPOSE: Individualised interventions are recommended to tackle malnutrition in older adults, but approaches for nursing home (NH) residents are scarce. This study investigated the effects of an individualised nutritional intervention in NH residents with (risk of) malnutrition. METHODS: In a pre-post study, 6 weeks (w) of usual care were followed by 6w of intervention. The intervention consisted of up to three supplement modules (sweet and savoury protein creams and protein-energy drink, single or combined) and, if required, reshaped texture-modified meals (RTMM). RESULTS: Fifty residents completed the study (84 ± 8 years, 74% female). One-third (32%) received RTMM. Additional 258 ± 167 kcal/day and 23 ± 15 g protein/day were offered. Mean daily energy intake increased by 207 (95%CI 47-368, p = 0.005) kcal and protein intake by 14 (7-21, p < 0.001) g (w12 vs w1). Quality of life (QoL) increased in the subscale "care relationship" (+ 9 (3-15) points, p = 0.002, w12 vs w6). Body weight, handgrip strength, and other QoL subscales did not change. CONCLUSION: Our intervention improved dietary intake and one QoL subscale in NH residents with (risk of) malnutrition. As a next step, randomized controlled trials are needed to investigate the impact of individualised interventions more comprehensively.

Nutritional status according to the mini nutritional assessment (MNA)® as potential prognostic factor for health and treatment outcomes in patients with cancer - a systematic review.

BACKGROUND: Patients with cancer have an increased risk of malnutrition which is associated with poor outcome. The Mini Nutritional Assessment (MNA®) is often used in older patients with cancer but its relation to outcome is not known. METHODS: Four databases were systematically searched for studies relating MNA-results with any reported outcome. Two reviewers screened titles/abstracts and full-texts, extracted data and rated the risk of bias (RoB) independently. RESULTS: We included 56 studies which varied widely in patient and study characteristics. In multivariable analyses, (risk of) malnutrition assessed by MNA significantly predicts a higher chance for mortality/poor overall survival (22/27 studies), shorter progression-free survival/time to progression (3/5 studies), treatment maintenance (5/8 studies) and (health-related) quality of life (2/2 studies), but not treatment toxicity/complications (1/7 studies) or functional status/decline in (1/3 studies). For other outcomes - length of hospital stay (2 studies), falls, fatigue and unplanned (hospital) admissions (1 study each) - no adjusted results were reported. RoB was rated as moderate to high. CONCLUSIONS: MNA®-result predicts mortality/survival, cancer progression, treatment maintenance and (health-related) quality of life and did not predict adverse treatment outcomes and functional status/ decline in patients with cancer. For other outcomes results are less clear. The moderate to high RoB calls for studies with better control of potential confounders.

Potentially modifiable determinants of malnutrition in older adults: A systematic review.

BACKGROUND & AIMS: Malnutrition in older adults results in significant personal, social, and economic burden. To combat this complex, multifactorial issue, evidence-based knowledge is needed on the modifiable determinants of malnutrition. Systematic reviews of prospective studies are lacking in this area; therefore, the aim of this systematic review was to investigate the modifiable determinants of malnutrition in older adults. METHODS: A systematic approach was taken to conduct this review. Eight databases were searched. Prospective cohort studies with participants of a mean age of 65 years or over were included. Studies were required to measure at least one determinant at baseline and malnutrition as outcome at follow-up. Study quality was assessed using a modified version of the Quality in Prognosis Studies (QUIPS) tool. Pooling of data in a meta-analysis was not possible therefore the findings of each study were synthesized narratively. A descriptive synthesis of studies was used to present results due the heterogeneity of population source and setting, definitions of determinants and outcomes. Consistency of findings was assessed using the schema: strong evidence, moderate evidence, low evidence, and conflicting evidence. RESULTS: Twenty-three studies were included in the final review. Thirty potentially modifiable determinants across seven domains (oral, psychosocial, medication and care, health, physical function, lifestyle, eating) were included. The majority of studies had a high risk of bias and were of a low quality. There is moderate evidence that hospitalisation, eating dependency, poor self-perceived health, poor physical function and poor appetite are determinants of malnutrition. Moderate evidence suggests that chewing difficulties, mouth pain, gum issues co-morbidity, visual and hearing impairments, smoking status, alcohol consumption and physical activity levels, complaints about taste of food and specific nutrient intake are not determinants of malnutrition. There is low evidence that loss of interest in life, access to meals and wheels, and modified texture diets are determinants of malnutrition. Furthermore, there is low evidence that psychological distress, anxiety, loneliness, access to transport and wellbeing, hunger and thirst are not determinants of malnutrition. There appears to be conflicting evidence that dental status, swallowing, cognitive function, depression, residential status, medication intake and/or polypharmacy, constipation, periodontal disease are determinants of malnutrition. CONCLUSION: There are multiple potentially modifiable determinants of malnutrition however strong robust evidence is lacking for the majority of determinants. Better prospective cohort studies are required. With an increasingly ageing population, targeting modifiable factors will be crucial to the effective treatment and prevention of malnutrition.

Size Matters! Differences in Nutritional Care between Small, Medium and Large Nursing Homes in Germany.

OBJECTIVES: The aim of this study is to comprehensively describe nutritional care in German nursing homes (NHs) and to examine if nutritional care differs between small, medium and large NHs. DESIGN: Nationwide cross-sectional postal survey. SETTING: Nursing homes. PARTICIPANTS: 541 NHs across Germany. MEASUREMENTS: Information on structural NH characteristics and nutritional care (food provision and menu planning, nursing care, and management and quality assurance) was collected by means of a questionnaire addressed to the management of a random sample of German NHs. NHs were grouped by size as small (≤ 50 beds), medium (50 - 100 beds) or large (> 100 beds) institutions. Frequencies were used to describe nutritional care, and Chi2-test to identify differences in nutritional care by NH size. RESULTS: Aspects in the domain of food provision and menu planning regarding food variety and choice were widely implemented in German NHs (77 - 100 %). Best results were achieved in the domain of nursing care, where all aspects were implemented in at least 68 % of the NHs. Aspects regarding management and quality assurance, especially those concerning staffing, i.e. the availability of an interface manager (14 %), an interdisciplinary nutrition team (12 %) and a dietician (42 %), were only rarely implemented. Differences by NH size were found between small and medium or large NHs. On the one hand, small NHs stated more often to consider individual capabilities of the residents with texture-modified food (81 % vs. 60 %, p<0.05) and produce more often hot meals at ward level on a regular base (46 % vs. 32 %, p<0.05) than large NHs. On the other hand, several aspects regarding food provision and menu planning, and management and quality assurance were significantly more often implemented in larger than smaller NHs. CONCLUSION: Whereas kitchen and nursing-related aspects of nutritional care seem to be widely implemented in German NHs, management and quality assurance demands are often not met. The differences found by NH size support the hypothesis that the number of residents living in a NH has an impact on how nutritional care is performed.

Energy and Protein Intake, Anthropometrics, and Disease Burden in Elderly Home-care Receivers--A Cross-sectional Study in Germany (ErnSIPP Study).

OBJECTIVE: To date, no study has examined the nutritional status and disease burden of elderly home-care receivers living in Germany. Aim of this cross-sectional study was, first, to assess disease burden and nutritional status, denoted in anthropometrics, and, second, to investigate associations between anthropometrics and disease burden. DESIGN: Cross-sectional multi-centre study. SETTING: Home-care receivers living in three urban areas of Germany in 2010. PARTICIPANTS: 353 elderly (>64 years) in home care (128 males aged 79.1 ±7.8 years, 225 females aged 82.0 ±7.5 years). MEASUREMENTS: Nutritional status was assessed by body mass index (BMI), mid upper arm circumference (MUAC) and calf circumference (CC). Medical conditions were assessed in personal interviews. A 3-day prospective nutrition diary was kept. Metric data are reported as mean±SD or median (interquartile range), p<0.05 was considered significant. RESULTS: Most participants were substantially (59%), and 11% severest in need of care. The seniors suffered from 5 (4-7) chronic diseases; dementia, depression, stroke, and respiratory illness were most prevalent (each 20-40%). More than one-third of participants had only moderate or poor appetite, nearly half were unable to eat independently. Chewing problems were reported for 52% of study participants, and more than one quarter of elderly had swallowing problems. Daily mean energy intake was 2017±528 kcal in men (n=123) and 1731±451 kcal in women (n=216; p<0.001). Mean protein intake amounted to 1.0 g/kg body weight. Mean BMI was 28.2±6.2 kg/m² (n=341), 14% of seniors had a BMI <22 kg/m² (including 4% with BMI <20 kg/m²). Critical MUAC (<22 cm) was indicated in 6% of subjects; and CC <31 cm in 11% of men, 21% of women (p<0.05). After adjusting for sex and age, BMI, MUAC and CC were negatively associated with high care level, hospitalization in the previous year, nausea/vomiting, prevalence of dementia, poor appetite, and eating difficulties like dependency, chewing and swallowing problems. CONCLUSION: We recommend to pay special attention to the nutritional status of elderly persons in home-care exhibiting named disease burden.

Malnutrition is related to functional impairment in older adults receiving home care.

OBJECTIVES: The aims of this work were (a) to provide a detailed description of the association between nutritional (Mini Nutritional Assessment; MNA®) and functional status in a sample of older adults receiving home care, using both questionnaire- and performance-based functional methods, and (b) to investigate the impact of different MNA subscales on this association. DESIGN: Multi-centre, cross-sectional. SETTING: Home care. PARTICIPANTS: 296 persons ≥65 years in need of care (80.7±7.7 y). MEASUREMENTS: Nutritional status was determined by the MNA and functional status by two questionnaires (Instrumental and Basic Activities of Daily Living; IADL, ADL) and three performance tests (handgrip strength, HGS; Short Physical Performance Battery, SPPB; Timed 'Up and Go' Test, TUG). A categorical and a covariance analytical approach were used to test for differences in functional status between MNA groups (well nourished, risk of malnutrition, malnourished). In addition, functional parameters were correlated with total MNA, a modified MNA version (modMNA), where functional items were excluded, and MNA subscales ('functionality', 'general assessment', 'anthropometry', 'dietary assessment', and 'subjective assessment'). RESULTS: 57% of the participants were at risk of malnutrition and 12% malnourished. 35% reported severe limitations in IADL, 18% in ADL. 40%, 39% and 35% had severe limitations in HGS, SPPB and TUG; 9%, 28% and 34% were not able to perform the tests. Functional status deteriorated significantly from the well nourished to the malnourished group in all functional measures. The modMNA was weak but still significantly related to all functional parameters except TUG. The subscale 'functionality' revealed strongest correlations with functional measures. All other MNA subscales showed only weak or no associations. CONCLUSION: More than one half of the seniors receiving home care were at nutritional risk and poor functional level, respectively. Malnutrition according to MNA was significantly associated to both questionnaire- and performance-based functional measures even after exclusion of functional MNA items.

Longitudinal study on potential neurotoxic effects of aluminium: I. Assessment of exposure and neurobehavioural performance of Al welders in the train and truck construction industry over 4 years.

OBJECTIVES: Previous cross sectional studies on potential neurotoxic effects of long-term aluminium exposures by aluminium welders lack clear interpretable results for methodological reasons. The present longitudinal study examined on the one hand the reliability and representativity of Al-biomonitoring as indicator of individual long-term exposure and on the other hand the long-term changes of neurobehavioural performance in Al welders in relation to Al exposure and neurobehavioural performance changes of a non-exposed control group. METHODS: The longitudinal study compared repeatedly measured exposure data and neurobehavioural data of 20, initially 44, male Al welders in the train and truck construction industry with data of a control group of similar age on the basis of three investigations over a period of 4 years. The repeated measurements of exposure included total dust in air as well as Al in pre- and post-shift plasma and urine samples. Neurobehavioural methods comprised symptoms, verbal intelligence, logic thinking, psychomotor behaviour, memory, and attention. Computer-aided tests from the Motor Performance Series (MLS) and the European Neurobehavioural Evaluation System (EURO-NES) were used. The characteristics of the biomonitoring data and the relationship to neurobehavioural data were examined with methods of correlation and regression analysis. The courses of neurobehavioural changes were analysed with multivariate covariance-analytical methods (MANCOVA) considering the covariates age, indicators of 'a priori' intelligence differences (education or 'premorbid' intelligence), and alcohol consumption (carbohydrate-deficient transferrin in plasma, CDT). RESULTS: The mean total dust load during welding, near to the routinely worn ventilated helmets, was in the range of 5-8 mg/m(3). The biomonitoring data of the welders (pre-shift: 88-140 microg Al/g creatinine in urine; 13-16 microg Al/l plasma) showed a high long-term stability but also sensitivity to acute shift dependent exposure changes. The Al welders who had been working in this profession at an average of 15 years showed no significantly increased symptom levels compared with the control group. Explorative regression and covariance analyses revealed neither a correlation between biomonitoring and performance variables nor a significant difference between Al-exposed and controls in the performance courses during the 4 years period. Explorative modelling indicated that the structure of neurobehavioural outcomes could be determined by possible indicators of intellectual 'a priori' (premorbid) differences between subjects but not by their exposure information. CONCLUSIONS: Compared to studies in the literature this study is characterized by relatively high and non-confounded Al exposure of the welders, a repeated-measurement design, and multivariate analyses. However, the long-term stable interindividual differences of internal Al exposure were not related to interindividual differences in neurobehavioural performances. Additionally, the lack of processual changes of neurobehavioural performances during the observation phase and the insignificant group differences do not make it very probable that degenerative processes caused by Al had happened before study onset or stopped just at this time point.

Longitudinal study examining the neurotoxicity of occupational exposure to aluminium-containing welding fumes.

OBJECTIVES: The neurotoxicity of occupational exposure to aluminium (Al)-containing welding fumes has been discussed with controversial results. The aim of the longitudinal study was to examine a group of Al welders for significant central nervous changes in comparison with a non-exposed cohort. METHODS: A group of 98 Al welders (mean age 37 years) in the car-body construction industry, with a median of 6 years of occupational exposure to Al welding fumes, and an education-matched, gender-matched, age-matched control group of 50 car-production workers (mean age 36 years) at the same plant, were included in this longitudinal study. Two cross-sectional studies were done in 1999 and 2001. In the second cross-sectional study 97 welders and 50 controls could be examined. The examination programme consisted, for example, of a standardised anamnesis, focussing on occupational history, education, illnesses, medication, accidents and current alcohol consumption, a physical examination that included neurological status, and the assessment of Al concentration in plasma and urine. The neurobehavioral methods included a symptom questionnaire, modified Q16, and computerised and non-computerised tests: psychomotor performance (steadiness, line tracing, aiming, tapping), verbal intelligence (WST), simple reaction time, digit span, block design (HAWIE), symbol-digit substitution, digit span, switching attention (European neurobehavioral evaluation system, EURO-NES), and standard progressive matrices. The data were analysed by multivariate analysis of covariance (MANCOVA) for repeated measurements with covariates age, education, and carbohydrate-deficient transferrin in plasma (CDT). RESULTS. The median Al urine concentration (mean preshift/postshift) was 52.4 microg/g creatinine (2001) and 57.6 microg/g creatinine (1999). Median respirable air dust was 0.67 mg/m(3) (2001) and 0.47 mg/m(3) (1999). Welders and controls did not report significantly more symptoms in the modified Q16. Furthermore, no significant differences in psychomotor performance and other neurobehavioral tasks, except for reaction time, were seen between welders and non-welders. Regression analyses reveal a significant relationship between reaction time and Al excretion in urine that was confounded by other factors. CONCLUSIONS: At present the outcome for reaction time has to be interpreted as a single result. However, as the modified Q16 questionnaire and the rest of the psychomotor performance showed no significant changes, the next cross-sectional study, in 2003, will provide further information on which a final conclusion can be based.

Physiological and psychological approaches to chemosensory effects of solvents.

Workplace related standard settings for solvents are based in a remarkable extent on information about sensory irritations. However, data from controlled human exposure studies are seldom available. Therefore, the aim of this study was to present the association of self-reported symptoms and physiological processes leading to sensory irritations. Three series of laboratory experiments each with 24 young male subjects were performed. Ethyl benzene (EB), 2-butanone (methyl ethyl ketone or MEK), isopropyl alcohol (IPA), 1-octanol (OCT), and 2-ethylhexanol (EHEX) were investigated in low and high concentrations. Ratings for sensory irritations (eyes and nose), olfactory symptoms, and annoyance were assessed repeatedly before, during and after the 4-h-exposures. The anterior active rhinomanometry (AAR) was employed measuring the nasal flow. The nasal lavage was used for the analysis of the neuropeptide substance P as indicator of nasal chemosensory irritations. Goodness-of-fit was calculated for non-linear regression analyses by fitting the sine function on the data of the ratings given during the 4-h-exposure. In general, ratings for annoyance and odor symptoms were fitted on a higher level than those for sensory irritations. However, a high fit could be shown for nasal irritations due to EHEX. In these experiments, a significant reduction of the nasal flow and a significant increase of substance P could be proved.

Subjective symptoms due to solvent mixtures, dioxin, and toluene: impact of exposure versus personality factors.

In this study, we analyse the impact of personality factors on the frequency of self-reported symptoms for workers under different exposure conditions. Reported symptoms may depend on the level and type of exposure, as well as on personality factors such as trait anxiety of the worker or his general sensitivity with regard to the environment. The employed data stems from three studies: The first study contains information of 60 workers who suspected to be exposed to polychlorined dibenzodioxins and dibenzofuranes (Lifetime Weighted Average Exposure, LWAE, as an index for contact with the substances). The second study concerns 40 workers who are exposed to different concentrations of solvent mixtures in paint manufacturing (LWAE of total hydrocarbons about 10 ppm). The third study includes repeated measurements of two subgroups of workers from rotogravure printing plants who are exposed to different concentrations of toluene: a "high" exposure group (n = 129, LWAE about 46 ppm, current exposure 25 ppm) and a "low" exposure group (n = 96, LWAE for toluene about 9 ppm, current exposure 3 ppm). Trait anxiety, environmental sensitivity, and self-reported symptoms are measured by validated questionnaires and age as well as verbal intelligence are controlled. To determine the effect of the individual characteristics and the different exposures on self-reported symptoms, frequency analyses and variance analyses are conducted and linear models are fitted. For all analyses, trait anxiety explains the highest share of the variance. If there is no effect of the exposure on the reported symptoms (dioxin and low-level toluene study), trait anxiety seems to have a larger explanatory power in comparison with those studies where the exposure has an effect on the reported symptoms (solvent-mixture and high-level toluene study). Neurotoxicological risk analysis has to account for the detected dependence of self-reported symptoms on personality traits: assessments for elevated symptoms should not only be linked to the intensity of exposure but also related to benchmarks derived from the normal variability of personality factors.

Neurobehavioral study on the interactive effects of age and solvent exposure.

Initial research revealed interaction effects on health measures between exposure to neurotoxicants and age. Symptom reports of workers were conspicuously increased if high-concentration occupational exposure (e.g. to organic solvents, lead) was combined with age above 54 years. The symptom increase in elderly workers was interpreted as a possible indicator of a biological vulnerable phase or delayed response of former high exposure. A second study of the hypothesized age-exposure interaction was performed with a group of workers who had homogenous exposure to a single organic solvent using a neurobehavioral performance evaluation (the EURO-NES). Workers in the rotogravure printing industry who were exposed to toluene were examined two times with an interval of one year (n =333/278). The sample was stratified by workers with significantly different toluene exposure, printers and end-processing operators, and four age classes (< 31, 31-40, 41-50, > 50). The mean lifetime weighted average exposure (LWAE) varied depending on age classes and years of employment with exposure between 7 and 17 ppm in the operators and between 35 to 62 ppm toluene in the printers. Multivariate analyses revealed a significant performance decrease with age (simple reaction time, symbol digit, switching attention, digit span). Again an interaction between age and exposure was found depending on diverging psychometric performance trends with older age. However, contrary to the hypothesis the group with higher exposures (printers) and older age revealed better performance and less symptoms than the group with lower exposure (end-processing operators). The paradoxical results are explained by differences in the intellectual capability in the oldest strata and a possible reversibility of neurobehavioral effects of former high toluene exposure under the condition of later low exposure. There are no hints of adverse delayed effects of former toluene exposure in a possible vulnerable phase in age over 50 years. The different interaction findings of the initial and present study seem to depend mainly on exposure differences in quality and quantity.

Psychological effects upon exposure to polyhalogenated dibenzodioxins and dibenzofurans.

Thirty workers who had been exposed to combustion products for several years due to testing of flame retarding qualities of building materials and 30 controls from the same facility were investigated. Concentrations found in samples taken from different places of the facility were up to 14,660 microg/kg for polybrominated dibenzofurans and up to 67.1 microg/kg for polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs). Physical examination, routine laboratory parameters, and blood fat concentrations of PCDDs and PCDFs revealed normal findings. Neurotoxic symptoms showed a weak tendency of overrepresentation among the exposed workers. The frequency of neurobehavioural symptoms increased significantly with trait anxiety independent of exposure to combustion products.

'Multiple chemical sensitivity', the relevance of toxic, neurobiological and psychic effect mechanisms.

The review deals mainly with the key question of chemical causation of multiple chemical sensitivity (MCS). There are only few human studies with valid information on chemical exposure and in no study the chemical toxic causation hypothesis is supported. The animal model of olfactory-limbic/neural sensitization is of heuristic value to explain MCS phenomena and includes both chemical and non-chemical stressors. However, in animal studies seldom chemical substances and exposure levels were used which might be of relevance in the formation of MCS. The problem is demonstrated for toluene exposures in human and animal sensitization studies. In accordance with the sensitization hypotheses, human studies prove a generalized vulnerability to environmental stimuli in subjects with self-reported MCS. However, study designs do not allow to deduce whether the strong responsivity is a premorbid or comorbid phenomenon or is related to exposure. Alternative study approaches to evaluate dose-response relationships are proposed.

Effects of sleep loss, time of day, and extended mental work on implicit and explicit learning of sequences.

Tacit knowledge is part of many professional skills and can be studied experimentally with implicit-learning paradigms. The authors explored the effects of 2 different stressors, loss of sleep and mental fatigue, on implicit learning in a serial-response time (RT) task. In the 1st experiment, 1 night of sleep deprivation was shown to impair implicit but not explicit sequence learning. In the 2nd experiment, no impairment of both types of sequence learning was found after 1.5 hr of mental work. Serial-RT performance, in contrast, suffered from both stressors. These findings suggest that sleep deprivation induces specific risks for automatic, skill-based behavior that are not present in consciously controlled performance.

Solvent Exposure, Shiftwork, and Sleep.

The effects of different conditions of occupational exposure to organic solvents on subjective sleep quality were studied with and without shiftwork. Laboratory studies showed that four hours of daytime exposure to ethanol (400, 800 ppm) by inhalation led to blood ethanol levels below 0.01 per thousand and had marginal effects on the following night's sleep. Exposures to acetone (1,000 ppm), ethyl acetate (400 ppm), and a solvent mixture (acetone 500 ppm, ethyl acetate 200 ppm) increased the subjective depth of sleep. In a field study with eight hours of exposure, during three different work shifts, dose-response relationships between acetone concentrations during the shiftwork and the depth of sleep were found. Nevertheless, the solvent-exposed shift workers reported a reduced sleep quality, mainly in connection with daytime sleep, in comparison with non-exposed shift workers. The effects of solvent exposure during shiftwork on sleep varied with time of day of the exposure.

Standardization of a questionnaire for neurotoxic symptoms.

A new version of the "Psychological-Neurological Questionnaire," designed for screening purposes, was investigated concerning its sensitivity to detect early signs of occupational exposure to potential neurotoxicants. A study population of 361 subjects was stratified into four age groups (<34, 35-44, 45-54, and >54 years) and three exposure groups (no, low, and high). According to dose and exposure history, workers exposed to dioxins and furans in combustion products, to volatile organic compounds, and to chromates were classified as low exposure. Workers exposed to alkyl lead, single solvents, and solvent mixtures were classified as high exposure. Only the group with the oldest age and highest exposure could be separated clearly from other groups, indicating an interaction effect between exposure and age. The low-exposure group could not be separated from the nonexposed controls. The most effective discriminators were neurologic symptoms. Psycho- and neurovegetative lability and irritative disturbances contributed less to the differentiation. Gastrointestinal and sleep disorders, as well as alcohol intolerance, showed no differentiation quality. The observed type of interaction effect fits models of delayed neurotoxicity.

Solvent exposure and ratings of well-being: dose-effect relationships and consistency of data.

Ratings on analog scales for dimensions of well-being provide information about the acute state of well-being during solvent exposure. In a study of volunteers and workers exposed to solvents, tension, tiredness, complaints, and annoyance were rated on seven-point scales. Dose-effect relationships were analyzed for several scenarios; data were collected in diaries during work hours. In two studies, 40 volunteers in an exposure laboratory were exposed to ethanol by inhalation at levels between 80 and 1900 parts per million (ppm). In two other studies, 32 volunteers were exposed to acetone and ethyl acetate in single exposures (1000 and 500 ppm, respectively) and combined exposures (500 ppm acetone + 200 ppm ethyl acetate). A field study of 8 exposed workers and 8 nonexposed controls involved exposures of up to 2100 ppm acetone. Dose-effect relationships were shown for ratings of annoyance by correlations of 0.36 (ethanol) and 0.58 (acetone). Similar coefficients were found for ratings of complaints. The dimensions tension and tiredness showed no stable relationship with exposure. The consistency of ratings was assessed by means of correlations between the ratings given during periods of nearly equal exposures. Ratings of annoyance for the different studies between the periods of nearly equal exposure showed average correlations from 0.68 to 0.84. For the ratings of complaints, the coefficients were 0.53 to 0.81. The coefficients for tension had similar stabilities; those for tiredness were lower.

Neurobehavioral effects of solvents and circadian rhythms.

Two studies on the combined neurobehavioral effects of shiftwork and solvent exposure were performed: two-shift work/mixed solvent exposure and three-shift work/single solvent exposure (acetone). Repeated measurements of exposure, body temperature, well-being, complaints, and performance were taken during each shift and during several shift cycles. The air concentrations of the solvent mixture were clearly below and of acetone were near the occupational exposure limit values. Both the exposure quality and the circadian factor contributed to the stronger adverse effects under the three-shift condition. The results support the view that exposure effects should be studied and evaluated in relation to shift and time.