Cold in- and outdoor work can result in different adverse effects on human health. Health problems decrease performance and work productivity and increase the occurrence of accidents and injuries. Serious health problems can also result in absence from work due to sick leave or hospitalization. At its worst, work in cold conditions could be associated with deaths due to cold-related accidents or a sudden health event. Musculoskeletal complaints, like pain, aches etc. are common in indoor cold work. Breathing cold air while working may lead to respiratory symptoms, which can decrease performance in cold. The symptoms are usually worsened by exercise and ageing, being more common in persons having a respiratory disease. Cardiovascular complaints and related performance decrements could be especially pronounced during work in cold weather and involving physical exercise, especially among those with an underlying cardiovascular disease. The article also reviews the current information related to diabetes, skin disorders and diseases, as well as cold injuries and accidents occurring in cold work. Increasing awareness and identifying workplace- and individual-related cold risks is the first step in proper cold risk management. Following this, the susceptible population groups need customized advice on proper prevention and protection in cold work.
Nowdays, occupational and recreational activities in cold environments are common. Exposure to cold induces thermoregulatory responses like changes of behaviour and physiological adjustments to maintain thermal balance either by increasing metabolic heat production by shivering and/or by decreasing heat losses consecutive to peripheral cutaneous vasoconstriction. Those physiological responses present a great variability among individuals and depend mainly on biometrical characteristics, age, and general cold adaptation. During severe cold exposure, medical disorders may occur such as accidental hypothermia and/or freezing or non-freezing cold injuries. General cold adaptations have been qualitatively classified by Hammel and quantitatively by Savourey. This last classification takes into account the quantitative changes of the main cold reactions: higher or lower metabolic heat production, higher or lesser heat losses and finally the level of the core temperature observed at the end of a standardized exposure to cold. General cold adaptations observed previously in natives could also be developed in laboratory conditions by continuous or intermittent cold exposures. Beside general cold adaptation, local cold adaptation exists and is characterized by a lesser decrease of skin temperature, a more pronounced cold induced vasodilation, less pain and a higher manual dexterity. Adaptations to cold may reduce the occurrence of accidents and improve human performance as surviving in the cold. The present review describes both general and local cold adaptations in humans and how they are of interest for cold workers.
Many persons world wide are exposed to cold environments, either indoors for example in cold stores, or outdoors. Cold is a hazard to health and may affect safety and performance of work. Basis for the creation of safe and optimal working conditions may be obtained by the application of relevant international standards. ISO 110791) presents a method for evaluation of whole body heat balance. On the basis of climate and activity a required clothing insulation (IREQ) for heat balance is determined. For clothing with known insulation value an exposure time limited is calculated. ISO 11079 also includes criteria for assessment of local cooling. Finger temperatures should not be below 24℃ during prolonged exposures or 15℃ occasionally. Wind chill temperature indicates the risk of bare skin to freeze for combinations of wind and low temperatures. Special protection of airways is recommended at temperatures below -20℃, in particular during heavy work. Additional standards are available describing evaluation strategies, work place observation checklists and checklist for medical screening. Risks associated with contact with cold surfaces can be evaluated with ISO 137322). The strategy and principles for assessment and prevention of cold stress are reviewed in this paper.
Protection of humans working in open areas during a cold period is of great importance. Cold influences human heat state, health and functional capacity. The assessment criteria for optimal permissible heat state during work time and maximum permissible heat state demanding regulation of cold exposure time are described. They form the basis for estimation and forecast of cold risk. Classification of cooling risk is made on the basis of factors such as mean skin temperature, heat deficit, strain of thermo regulative reactions, thermal sensation, and occupational conditions. Cooling risk is also dependent on human factors such as metabolic rate and clothing thermal insulation and ambient conditions such as air temperature, wind velocity, and exposure time. For evaluation of the cooling risk a regression equation is presented for determination of the integral index of cooling conditions (IICC). On basis of the IICC value, presented in a nomogram it is possible to predict the probability of cooling risk of various rates. In consideration of the shifting climate conditions of Russia, requirements for thermal insulation of protective clothing for four major climate regions of the country are presented.
The paper summarizes the research on cold protection of feet. There exist several conflicting requirements for the choice of the best suited footwear for cold exposure. These conflicts are related to various environmental factors, protection needs and user comfort issues. In order to reduce such conflicts and simplify the choice of proper footwear the paper suggests dividing the cold into specific ranges that are related to properties and state of water and its possibility to penetrate into, evaporate from or condensate in footwear. The thermo-physiological background and reactions in foot are briefly explained, and main problems and risks related to cold injuries, mechanical injuries and slipping discussed. Footwear thermal insulation is the most important factor for protection against cold. The issues related to measuring the insulation and the practical use of measured values are described, but also the effect of socks, and footwear size. Other means for reducing heat losses, such as PCM and electrical heating are touched. The most important variable that affects footwear thermal insulation and foot comfort is moisture in footwear. In combination with motion they may reduce insulation and thus protection against cold by 45%. The paper includes recommendations for better foot comfort in cold.
The questions related to safety at work in cold environments and prevention of cold stress in working life are described in this article. Working in the cold environment is more dangerous than the same type of work in a warmer climate. All researchers have concluded that the frequency of accidents/versus temperature curves follow the U-shape with the minimum near 20℃. The effects of low temperature can be divided into direct, typically frostbites, and indirect, of which the indirect effects, typically slipping accidents, are more common. In improving risk management in cold conditions the risk evaluation based on existing standards is the starting point. Prevention of risks in cold environments can be done by planning of work, technical measures like heating or reduction of cooling by protective clothing, training and other measures. Local heaters, shelters against bad weather, reduction of draught are good examples of means of improving working conditions and reducing accident risks. The local IR-heaters can increase skin temperature of fingers about 7℃ in normal cold work. The improvement of 3℃ can be reached by using insulating material in the handle of tools. By using these technical improvements we can reduce the health risks but also improve work performance and even energy savings at work places.
Manual performance during work in cold and windy climates is severely hampered by decreased dexterity, but valid dexterity decrease predictors based on climatic factors are scarce. Therefore, this study investigated the decrease in finger- and hand dexterity and grip force for nine combinations of ambient temperature (-20, -10 and 0℃) and wind speeds (0.2, 4 and 8 m·s2), controlled in a climatic chamber. Finger dexterity was determined by the Purdue pegboard test, hand dexterity by the Minnesota manual dexterity test and grip force by a hand dynamometer. Twelve subjects with average to low fat percentage were exposed to cold air for one hour with and without extra insulation by a parka. The subjects were clothed in standard work clothing of the Royal Netherlands Air Force for cold conditions. Extra insulation did affect cold sensation but not manual performance. The deterioration in manual performance appeared to be strongly dependent upon Wind Chill Equivalent Temperature (WCET) and the square root of exposure time (r=0.93 for group average). These simple models may be valuable to assess problems with work in the cold, but more work should be done to determine critical values in dexterity for a wide variety of operational tasks.
This questionnaire study evaluates how work ability and musculoskeletal symptoms associate with physical work factors and individual characteristics of the workers in cooled food-processing facilities. A total of 1,117 workers (response rate 85%) responded to the study. Poor work ability was significantly associated with longer work duration, experience of draught at the workplace, absence from work due to health reasons, and physical inactivity during free time. The amount of local cooling experienced was significantly associated with the risk for musculoskeletal symptoms in the neck-shoulder region, shoulders, wrists and lower back. Additionally, female gender, longer work duration and poor work ability were associated with the increased prevalence of the symptoms. The prevalence of musculoskeletal symptoms was significantly higher among older employees (40 to 64 yr) than among younger employees (18 to 39 yr) for all regions except wrists. Cold discomfort and unpleasant sensations due to the physical factors of work were significantly more common among females than males. The results showed that, in addition to individual characteristics of workers, factors related to work in a cool environment (experience of draught and cooling and long exposure to cold) are associated with poor work ability and musculoskeletal symptoms.
To help making comfortable workplaces and to prevent health disorders induced by the exposure to moderate cold in two different groups of out-door workers, we conducted a survey to compare subjective symptoms and cold prevention measures in winter between traffic control workers and construction workers. The subjects of this study were 98 male traffic control workers and 149 male workers engaged in building construction. Work loads of traffic control workers and construction workers were estimated at RMR1～2 and RMR2～4, respectively. All subjects were asked to complete a self-administered questionnaire covering age, occupational career, working figure, present illness, past history of diseases, individual preventive measures to the cold, subjective symptoms in the winter (43 items) and subjective symptoms occurred during daytime working in the winter (6 items). In two parts of the construction workplaces (the place where a morning assembly was held and on the 7th floor of the construction site) dry bulb, wet bulb and globe temperatures were measured in January. Windchill Index (kcal/cm,2·h) was calculated by the measured dry bulb temperature and wind velocity. Mean values of dry bulb temperature between 9:00 and 16:30 in the place where a morning assembly was held for three days were between 4.8 ± 1.2℃ at 9:00am and 9.3 ± 1.1℃ at noon. Mean values of Windchill Index in the place where a morning assembly was held were between 490.8±23.9 kcal/cm2·h at 9:30am and 608.2±47.3 kcal/cm2·h at 2:30pm. Occupational career, monthly working days, daily working hours, one way commuting hours, and daily smoking numbers of the traffic control workers were significantly shorter than the construction workers (p<0.01). There were no significant differences in the prevalence of chillness in the arms and legs between the traffic control workers (5.1%) and the construction workers (0.7%). Prevalence of wearing a warm underwear, body warmer, warm trousers, underpants, warm socks, shoe warmer and muffler in the traffic control workers were significantly higher than the construction workers. The subjective symptoms in winter complained most frequently were shoulder stiffness (51.0%), finger cold sensation (50.0%) and neck stiffness (48.0%) in the traffic control workers, and were easy to get fatigued (49.0%), lumbago (48.3%) and finger cold sensation (47.7%) in the construction workers. On the basis of the results obtained, it is clearly shown that the two groups are at the risk of disorders due to their working environment. Therefore, these workers are needed to undergo occupational health programs for prevention of cold exposure disorders. Applications of preventive countermeasures for both groups are discussed.
To seek the factors associated with the degree of Japanese workers' satisfaction with their annual health checkups, a survey with an anonymous self-administered questionnaire was conducted. A total of 1,389 questionnaires were analyzed. The average age of the analyzed subjects was 37.4 yr (range, 18-66 yr). Multiple linear regression analysis showed that the degree of such satisfaction was significantly associated with the effectiveness of annual health checkups, the hassle of receiving them, the receptionist's good manners, cleanliness of the examination site, the long waiting time, privacy invasion issues, anxiety concerning the skills of the persons conducting the examinations, and helpful advice from a physician. Various activities including promoting primary preventions, e.g., medical education must be conducted to convey the effectiveness of annual health checkups to examinees and to reduce the hassle of receiving those checkups. Health checkup staffs must keep their health checkup sites clean and try to find ways to reduce the waiting time. Moreover, they must pay particular attention to examinees' privacy. It is imperative that examinees are not anxious concerning the skills of the persons conducting the examinations. Many examinees want helpful advice from a physician regarding their health management.
An increasing body of evidence now suggests that menstrual disorders may influence the development of Low Back Pain (LBP) among women of reproductive age. To investigate this issue in Japan, we conducted a large cross-sectional survey of female nurses from a university teaching hospital during 2008. Nurses reported a wide range of symptoms both prior to and during menstruation, including breast tenderness, stomach pain, light headedness and fatigue. Around three-quarters had experienced at least one episode of LBP in the previous 12-months, with most symptoms lasting one week or less. Increasing body weight was correlated with an increased risk of LBP affecting their daily activities (OR: 12.94, 95%CI: 1.54-116.56). Having three or more children was correlated with a reduced risk of experiencing LBP (OR: 0.13, 95%CI: 0.01-0.97). Nurses who reported breast tenderness prior to menstruation were twice as likely to suffer LBP (OR: 2.09, 95%CI: 1.20-3.73), while those who reported breast tenderness during menstruation were almost twice as likely to suffer LBP that interfered with their daily activities (OR: 1.85, 95%CI: 1.06-3.32). Overall, our study suggests that reproductive symptoms and menstrual disorders may influence the development of LBP among Japanese nurses, although the magnitude of this effect appears to be less than that reported in some previous research.
The organophosphate pesticide trichlorfon is a widely used agricultural broad spectrum insecticide. The health effects on a developing fetus of low level exposure to trichlorofon ingested by the mother in contaminated foods are unclear. We assessed reproductive and developmental toxicity in pregnant female mice following gavage-administered exposure to distilled water or to low levels (12.5, 25, or 50 mg/kg body weight/d) of trichlorofon during organogenesis (gestation days 6-15). Following sacrifice on day 17, reproductive outcomes and teratogenesis were assessed. Trichlorfon exposure did not affect maternal weight gain, organ weights, corpora lutea, implantation sites, or reproductive success, nor where external or skeletal abnormalities evident. The lack of effects of trichlorfon on any in vivo reproductive and fetuses endpoints above suggested that for trichlorfon, a hazard of reproductive toxicity below 50 mg/kg body weight/d maybe not expected. However, a well-designed epidemiological study is necessary for further risk assessment of human developing fetus exposed to trichlorfon at a lower level.
This study assessed the relationships of lifetime smoking and initiating smoking with job demands among 2,888 randomly selected workers, aged 15 yr or over, using a post-mailed questionnaire. Cumulated job demands (CJD) was defined as the number of: using pneumatic tools, other vibrating hand tools, hammer, tasks at height, working in adverse climate, pace of working, cold, heat, and noise exposure. Lifetime smoking was reported by 63.8% of subjects, and 5.9% initiated smoking during present job. Logistic model shows that lifetime smoking related to the CJD: OR adjusted for years with job 2.47 (95%CI 1.69-3.60) for CJD≥4, 1.50 (1.21-1.85) for CJD2-3, and 1.20 (1.00-1.44) for CJD1, vs. CJD0. Initiating smoking also related to the CJD: ORs 3.72 (1.95-7.11), 1.51 (0.96-2.39) and 1.47 (0.97-2.24), respectively. These associations were partly confounded by gender, income, obesity and job. Smoking related to job demands and their limitation should help preventing smoking.
In this study, several exhaust ventilation systems were designed and implemented in a paint manufacturing factory, using ACGIH recommendations. The personal exposure of workers to solvents used in the factory was evaluated to examine the role of implemented standard ventilation system. For this purpose, Toluene and Xylene concentration were monitored before and after the application of ventilation systems. Personal samples and subsequent analysis were conducted according to OSHA's method No: 12. Samples were analyzed, using Gas Chromatography. The results showed that the ventilation standards recommended by ACGIH were able to control Toluene and Xylene vapors successfully below the recommended TLVs (e.g. 44.49 ppm and 97.73 ppm respectively). It was also discovered that although Benzene was not reported as a component of the paint, its concentration in breathing zone of workers were much higher than the respective TLV (e.g. 4.5 ppm). This could be from the impurity of solvents used in paint factories which raises new questions. According to IRIS epidemiologic information, it was found that implementation of industrial ventilation systems decrease the relative risk (RR) of leukemia due to exposure to benzene, from 66.4 to 3.2 cases per work life, in this factory. Finally it was deduced that solvents impurities such as Benzene should be seriously considered as a major problem that may not be controlled using ventilation standards recommended by ACGIH for paint mixing and storing process.
To examine the effectiveness of a computer-tailored support tool for lifestyle modification developed for employees, we conducted an intervention study of pre-post test design. The program was based on principles of behavior science referring to goal setting processes, self monitoring, and feedback. The program of the support process was fully automated. A total of 650 participants of four workplaces in Japan completed the baseline assessment, 185 (28.5%) of those returned for the post-test assessment 4 months later. There were significant improvements in lifestyle behaviors between baseline and post-test: In men, low energy intake (p<0.01) and exercise frequency (p<0.05), and in women, low salt intake (p<0.05) and exercise frequency (p<0.05). Furthermore, significant improvements were shown in the stage of change between baseline and post-test: Low salt intake (p<0.01) and regular exercise in men (p<0.01). Our results suggest a possibility that the program, utilizing a computer-tailored lifestyle modification support tool developed for use by employees, had a positive effect on participants' lifestyle behaviors in Japanese workplaces. The degree to which our results generalize to effects of the program is unclear but examination to develop more efficient and effective programs is warranted.