Sick Symptoms Research Articles

Prevalence of the sick building syndrome symptoms in office workers before and six months and three years after being exposed to a building with an improved ventilation system.

OBJECTIVE: The prevalence of symptoms associated with the sick building syndrome (SBS) has recently been shown to decrease by 40% to 50% among office workers six months after they were...

Relationships Between Ventilation and Indoor Air Quality: A Review

Abstract Adjustment of ventilation rates in buildings is widely practised, both to provide good air quality on a proactive basis and to mitigate air quality problems associated with occupant complaints. However, both cross-sectional and experimental epidemiological studies have reported mixed results and have for the most part failed to establish definitive relationships between ventilation rates and symptom prevalence or dissatisfaction with air quality. The difficulties involved in establishing such relationships may be due to a variety of confounding factors which include limitations in study design and interaction effects; difficulties in controlling ventilation rates in experimental studies; inadequate mixing of supply air in occupied spaces; high source strengths for some contaminants; dynamic interactions between sources and ventilation rates that result in increased contaminant emissions; contaminant dose-response sensory effects which are log-linear; potential contaminant generation within ventilation systems themselves; and multifactorial genesis of sick building symptoms. There is limited evidence to suggest that ventilation rate increases up to 10 L/s person may be effective in reducing symptom prevalence and occupant dissatisfaction with air quality and that higher ventilation rates are not effective. Because of complex relationships between ventilation rates, contaminant levels, and building-related health complaints/dissatisfaction with air quality, the use of ventilation as a mitigation measure for air quality problems should be tempered with an understanding of factors which may limit its effectiveness.

Prevalence of the sick building syndrome symptoms in office workers before and after being exposed to a building with an improved ventilation system.

To find if the prevalence of symptoms associated with sick building syndrome decreased among office workers after moving to a building with improved ventilation (after controlling for potential confounders). Workers in five buildings in 1991 all moved in 1992 into a single building with improved design, operation, and maintenance of the ventilation system. All buildings had sealed windows with mechanical ventilation, air conditioning, and humidification. Workers completed a self administered questionnaire during normal working hours in February 1991 and February 1992. The questionnaire encompassed symptoms of the eyes, nose and throat, respiratory system, skin, fatigue, headache, and difficulty concentrating, personal, psychosocial, and work related factors. During normal office hours of the same week environmental variables were measured. The study population comprised 1390 workers in 1991 and 1371 workers in 1992 who represented more than 80% of the eligible population. The prevalence of most symptoms decreased when workers moved to the new building: skin (54%), respiratory system (53%), nose and throat (46%), fatigue (44%), headache (37%), eyes (23%). These findings were all significant and remained generally similar after controlling for personal, psychosocial, and work related factors. Furthermore, more than 60% of workers symptomatic in 1991 were asymptomatic in 1992 for all types of symptoms. In contrast, less than 15% of workers were asymptomatic in 1991 but symptomatic in 1992 for all types of symptoms. In this study, the prevalence of most symptoms usually associated with the sick building syndrome decreased by 40% to 50% after workers were transferred to a building with an improved ventilation system. The results show that it is possible to diminish the prevalence of symptoms associated with the sick building syndrome among office workers occupying a building with mechanical ventilation, air conditioning, and sealed windows.

Individual and Occupational Correlates of the Sick Building Syndrome

Results of a questionnaire survey of 939 workers from 5 air-conditioned offices where smoking was prohibited are reported. Levels of carbon monoxide, carbon dioxide, formaldehde, respirable particulates, and temperature, relative humidity, and illuminance were measured in these buildings, but these did not correlate with symptom reports. The number of sick building syndrome symptoms per worker was related linearly to perceived indoor air quality, job stress, job satisfaction, allergies, eyewear, and seasonal affective disorder. Two hundred and fifty five of these workers also completed a battery of psychological measures. Measures of depression, personality variables, situational stress, vulnerability to stress, and individual differences in circadian rhythms did not correlate with the numbers of sick building syndrome symptoms per worker, although depression did correlate with the number of symptoms when these were weighted for their frequency of occurrence in the previous month. Job stress and perceptions of indoor air quality correlated with both the unweighted and weighted indices of sick building syndrome.

Why do women report ‘sick building symptoms’ more often than men?

The prevalence of general, mucosal and skin symptoms compatible with the ‘Sick Building Syndrome’ (SBS) was studied in Swedish office workers. The marked excess in symptom prevalence among females, 12% SBS cases as compared to 4% among males, was analysed with respect to differences in biological or acquired risks and different illness and reporting (interview) behaviour among males and females. The distribution of risk indicators for symptoms was recorded in a questionnaire to 4943 employees. The skin symptom questions were validated in a clinical examination. Most risk indicators, such as paper work and psychosocial work load, had an unfavourable distribution for females. In the multivariate analysis however, female sex remained the most prominent risk indicator almost unaffected by the addition of other factors. Neither did effect modification contribute to the excess prevalence among females. The results from the clinical examination indicate that the excess symptom prevalence among females is real and not a reporting artefact. As the factors studied did not explain the excess symptom prevalence among females, the sex differential observed can be a reflection of a general excess of psychosomatic symptoms among women. Although inequalities in social conditions did not substantially explain the sex differential in symptom reporting, the importance of life situation and social roles should be further explored. As the studied variables are surrogates for actual measurements, another important issue is whether sex differences in working conditions, entailing different hierarchical positions in the office, have consequences for indoor air quality factors that are important for the symptoms. The study strongly underlines the importance of taking the sex distribution into account when surveying risk indicators for SBS symptoms.

Sick building symptoms in office workers: a follow-up study before and one year after changing buildings.

Influences of physical and psychosocial work environments and personal factors on sick building syndrome symptoms were investigated in 167 clerical workers before and one year after moving from a naturally ventilated building to an artificially ventilated building. Female gender and work on visual display units were independently associated with most symptoms in the baseline survey and with the incident (new) symptoms in the follow-up survey. After changing buildings, the prevalences of eye, skin and fatigue symptoms increased significantly. Cold and discomfort due to stuffiness were independently associated with incident eye and respiratory symptoms. Reported domestic workloads were greater for women, but did not account for any gender differences in symptom prevalence.

Exposure of children to pollutants in house dust and indoor air.

This review summarizes occurrence and exposure studies for pollutants in house dust and related indoor air exposures. A standard sampling method and control methods to reduce these exposures are discussed, including recommendations for future research. Infants and toddlers receive a broad and significant range of exposures to lead, pesticides, PAHs, allergens, and VOCs in house dust and indoor air. Carpet dust in eight Columbus and nine Seattle homes contained concentrations of potentially carcinogenic PAHs ranging from 3 to 290 micrograms/g, of lead from 250 to 2250 micrograms/g, and of PCBs from 210 to 1900 ng/g. Dust collected from ten used sofas in Seattle averaged 16.3, 37.2, and 229 micrograms/g for dust mite allergen, cat allergen, and lead, respectively; dust samples showed mutagenic activity. Biological and chemical pollutants in indoor dust and air have been associated with lead poisoning, cancer, allergy, asthma, damage to the nervous system, and sick building symptoms. The 11% of toddlers who have pica tend to have the highest exposures and risks. Further, the exposure of toddlers to lead via the dust pathway can be greater than by other routes. Standard method ASTM 5438.94 for sampling house dust has been used to characterize current and chronic exposure of toddlers in epidemiological studies. The accumulation of dust, dust mites, and tracked-in soil in old carpets, sofas, and mattresses appears to be a major source of exposure to lead, pesticides, allergens, PAHs, and VOCs. Remodeling and energy conservation can reduce ventilation and increase relative humidity, dust, dust mites, molds, VOCs, and other indoor air pollutants. The U.S. faces large and increasing costs from asthma and allergy. Asthma incidence in the U.S. has increased from 0.5% in 1930 to 8%-12% in 1991. Asthma hospitalization rates for children are increasing at the rate of 4%/yr in the U.S. and 14%/yr in Seattle. Such hospital visits would be rare with effective diagnosis, patient education, and control of home exposures. Asthma was estimated to cost $6.2 billion in 1990; hospital visits of children in Seattle cost $2,526,000 in 1993. Forty percent of the U.S. population has been sensitized to allergens; one in three homes has high relative humidity, which favors dust mites, molds, allergies, asthma, and other respiratory diseases. Reducing indoor allergens can reduce costs, severity, and the risk of being sensitized and developing allergic disease. Use of volunteer Master Home Environmentalists to do free in-home surveys and education in Seattle may reduce immediate health costs from allergens as well as long-term risks from lead, carcinogens, and home chemicals.(ABSTRACT TRUNCATED AT 400 WORDS)

Influences on sick building syndrome symptoms in three buildings

Relationships between symptoms typical of sick building syndrome, musculoskeletal symptoms, and reported indoor environmental exposures, psychological state, work stress and interpersonal relationships at work, were investigated among 624 office workers in three buildings. Symptom prevalences were similar in the three buildings, and were slightly lower in the two buildings characterized by its inhabitants as ‘sick’ than in the one building not considered to be ‘sick’. Women were more likely than were men to complain of most symptoms in all three buildings. Multiple regression showed psychological symptoms and sex to be significant independent predictors of symptoms. Reported odours, and uncomfortable humidity and temperature were also independently associated with symptoms. The study indicates that sex and psychological symptoms are important predictors of perceived building related illness.

An investigation into sick building syndrome among local authority employees.

Self-administered questionnaires were used to find out the prevalence among employees working in the three local authority premises in a Health District of self-reported illness which could be associated with sick building syndrome. Eye symptoms were found to be more common among employees working in a typing centre using VDUs. The symptoms tiredness, lethargy and influenza-like ('flu-like) illness, including aches in the limbs, were reported in significantly higher numbers by employees working in areas where there was evidence of increased pressure of work and worries over job losses. Dry throat and blocked or stuffy nose were symptoms reported in significantly higher proportions by employees working in certain buildings, where anecdotal evidence suggested that there could be problems with temperature regulation. This study also confirmed findings by other studies that for some symptoms women complain in significantly higher numbers than men. It was concluded that the type of work people do, in addition to the type of building they work in, play an important role in self-reported illnesses. Causation of sick building syndrome is complex and probably of multifactorial origin.

Associations between type of ventilation and air flow rates in office buildings and the risk of SBS-symptoms among occupants

The association between type of ventilation and outdoor-air flow rates and Sick Building Syndrome (SBS) and SBS symptoms was studied in a cross-sectional questionnaire and field study comprising 160 office buildings, and 260–2649 respondents with case-controls as well as prevalence comparisons. Measured ventilation rates were higher than required by most building codes and consisted of fresh-air (outdoor-air) inflow of 17±14 L/p and 2.0±1.3 air changes/h. Increased risk of SBS and elevated prevalence of general SBS symptoms were associated with low outdoor-air flow rates, presence of copying machines in office rooms, and ventilation operating hours was less than 10 h/d. There was a suspected association between SBS and air humidification, recirculation of exhaust air at high outdoor-air flow rates but not at low outdoor-air flow rates, and with natural or mechanical exhaust ventilation systems. SBS was not associated with the presence of a rotary heat exchanger or with the supply air temperature higher than the room air temperature.

Effects of a Furniture-integrated Breathing-zone Filtration System on Indoor Air Quality, Sick Building Syndrome, and Productivity

A field experiment evaluated the effect of a furniture-inte-grated breathing-zone filtration (BZF) system on indoor air quality, worker comfort, health, and productivity. The BZF system tested filters office air to remove volatile organic compounds and airborne particulates. The BZF system was installed on one floor of a 29 story air-conditioned office building. Another floor of the building served as a control. Comparisons of pre-installation and three month post-instal-lation surveys showed improvements in indoor air quality, sick building syndrome symptoms, and self-reported pro-ductivity with the BZF system References

Smoking habits, atopy, and prevalence of sick building syndrome symptoms among office workers in Norway

The relative influence of sex, atopy, smoking habits, and age on reported sick building syndrome (SBS) symptoms among office workers was investigated through questionnaire studies among 1293 employees in 10 nonindustrial buildings. The occurrence of atopy among the office workers was not found to be different from that of the general population. Both sex and atopy were found to be important for the prevalence of SBS symptoms. The prevalence of symptoms was higher among atopic individuals than among nonatopics, and higher among females than among males. While sex was found important for some symptoms, atopy was important for all of them. Statistically significant differences in the prevalence of symptoms between smokers and non-smokers (i.e., never smokers) were not found. The results indicated interrelations between smoking and atopy, with enhanced prevalence of some symptoms. Age of the persons were also included in the present analyses. Different ways of grouping age indicated different trends in associations between age and the prevalence of symptoms, but the study did not show any unambiguous associations between the age and the prevalence of symptoms.

Sick building syndrome symptoms — Different prevalences between males and females

The importance of gender to the prevalence of the “sick building syndrome” symptoms was investigated by questionnaire studies in three office buildings in Norway. The study included 710 persons. Of these, 590 (83%) completed the questionnaires. The most important factor related to the differences in symptom prevalences was found to be the sex. A greater percentage of females than males reported having symptoms. A relatively frequent occurrence of symptoms was reported by a greater percentage of females than males. The difference between males and females within each building was greater than the corresponding differences between females and males respectively in different buildings. The results show that gender is of importance to the prevalence of symptoms recorded in indoor air questionnaire studies. It must be taken into account when analyzing the results; otherwise, the sex can be a confounding factor. Possible reasons for the observed differences are discussed.