Marginal structural model to evaluate the joint effect of socioeconomic exposures on the risk of developing end-stage renal disease in patients with type 1 diabetes: a longitudinal study based on data from the Swedish Childhood Diabetes Study Group.
Diabetic nephropathy is a severe complication of type 1 diabetes (T1D) that may lead to renal failure and end-stage renal disease (ESRD) demanding dialysis and transplantation. The etiology of diabetic nephropathy is multifactorial and both genes and environmental and life style-related factors are involved. In this study, we investigate the effect of the socioeconomic exposures, unemployment and receiving income support, on the development of ESRD in T1D patients, using a marginal structural model (MSM) in comparison with standard logistic regression models.
The study is based on the Swedish Childhood Diabetes Register which in 1977 started to register patients developing T1D before 15 years of age. In the analyses, we include patients born between 1965 and 1979, developing diabetes between 1977 and 1994, and followed until 2013 (n = 4034). A MSM was fitted to adjust for both baseline and time-varying confounders.
The main results of the analysis indicate that being unemployed for more than 1 year and receiving income support are risk factors for the development of ESRD. Multiple exposures over time to these risk factors increase the risk associated with the disease.
Using a MSM is an advanced method well suited to investigate the effect of exposures on the risk of complications of a chronic disease with longitudinal data. The results show that socioeconomic disadvantage increases the risk of developing ESRD in patients with T1D.
BACKGROUND: In studies in men, risk estimates on occupation and bladder cancer are distorted by about 10% when not adjusting for smoking. We examined the degree to which occupational risk estimates for bladder cancer in women are confounded by smoking, and the degree of residual confounding by inadequate control of this effect. METHODS: Primary data of 11 case-control studies on occupation and bladder cancer from Denmark, France, Germany, Greece, Italy, and Spain were pooled. Information for smoking and lifetime occupational history for 700 female cases and 2,425 female controls ages 30-79 was abstracted and recoded. Logistic regression was used to calculate odds ratios (OR) by occupation, applying five models which differed in their degree of adjustment for smoking. RESULTS: In major occupational groups, risk estimates were distorted by less than 10% when not adjusting for smoking. A statistically significant excess risk for bladder cancer was found in 13 specific occupations and industries. In most occupations, adjustment for smoking led the ORs towards the null value, but all statistically significant associations were maintained after adjustment. In three occupations (lathe operators, field crop workers, and wood manufacturers), a statistically significant excess risk was masked when not adjusting for smoking. In six occupations, estimates were distorted by more than 10% (-22% up to +40%). In occupations where smoking acted as a positive confounder, the proportion of confounding removed using a dichotomous smoking variable (ever/never) was around 60%. In one occupation (buyers), controlling for smoking status (ever, never) led to over-adjustment, because the percentage of smokers was high but the quantity smoked was low.
BACKGROUND: Pertussis vaccination in infancy has been suggested to increase the risk for development of asthma and allergy. OBJECTIVE: To assess sensitization rates and development of atopic diseases in a prospective randomized controlled trial of pertussis vaccine. PATIENTS AND METHODS: A total of 669 children were randomized to 1 of 4 vaccine groups (2-component acellular pertussis, 5-component acellular pertussis, whole-cell pertussis vaccines, and placebo [diphtheria and tetanus toxoids]). Diphtheria and tetanus toxoids were also given to the children in the pertussis vaccine groups. The children were evaluated by means of questionnaires at age 2 months, 7 months, and 2 1/2 years; skin prick tests at age 7 months and 2 1/2 years; and blinded clinical investigation at age 2 1/2 years. The families were contacted at regular intervals to assess possible adverse effects after the vaccinations and symptoms of whooping cough. RESULTS: The cumulative incidence of atopic diseases was 30% and incidence rates were similar in the 4 groups after adjusting for family history. Exposure to environmental tobacco smoke and home dampness did not confound these results. The frequency of adverse effects did not differ appreciably between atopic and nonatopic children, with the exception that a nodule at the vaccination site was more frequent after whole-cell pertussis vaccination in the nonatopic children. Among 47 children with proven pertussis, atopic disease appeared in 19 (40%). Of these 47 children, 9 (19%) developed asthma, as compared with 58 (9%) noninfected children (P=.03). CONCLUSIONS: We found no support for a drastic increase in allergic manifestations after pertussis vaccination. There was a positive association between whooping cough and asthma by 2 1/2 years of age. There seems to be little reason to withhold pertussis vaccination from infants, irrespective of family history of allergy.
BACKGROUND: The high and increasing prevalence of childhood asthma is a major public health issue. Various risk factors have been proposed in local studies with different designs. METHODS: We have made a questionnaire study of the prevalence of childhood asthma, potential risk factors and their relations in four regions in Scandinavia (Umeå and Malmö in Sweden, Kuopio in eastern Finland and Oslo, Norway). One urban and one less urbanized area were selected in each region, and a study group of 15962 children aged 6-12 years was recruited. RESULTS: The prevalence of symptoms suggestive of asthma varied considerably between different areas (dry cough 8-19%, asthma attacks 4-8%, physician-diagnosed asthma 4-9%), as did the potential risk factors. Urban residency was generally not a risk factor. However, dry cough was common in the most traffic polluted area. Exposure to some of the risk factors. such as smoking indoors and moisture stains or moulds at home during the first 2 years of life, resulted in an increased risk. However, current exposure was associated with odds ratios less than one. CONCLUSIONS: Our findings were probably due to a combination of early impact and later avoidance of these risk factors. The effects of some risk factors were found to differ significantly between regions. No overall pattern between air pollution and asthma was seen, but air pollution differed less than expected between the areas.
This questionnaire-based study found a significantly higher prevalence of chronic bronchitis, asthma, and several other symptoms in 116 Copenhagen street cleaners who were exposed to traffic-related air pollution at levels that were slightly lower than the 1987 World Health Organization-recommended threshold values, compared with 115 Copenhagen cemetery workers exposed to lower pollution levels. Logistic regression analysis, controlling for age and smoking, was conducted, and odds ratios and 95% confidence intervals were calculated to be 2.5 for chronic bronchitis (95% confidence interval = 1.2-5.1), 2.3 for asthma (95% confidence interval = 1.0-5.1), and 1.8-7.9 for other symptoms (95% confidence interval = 1.0-28.2). Except for exposure to air pollution, the two groups were comparable, i.e., they had similar terms of employment and working conditions. The exposure ranges during an 8-h work day, averaged from readings taken at five monitored street positions, were: 41-257 ppb nitric oxide (1-h max: 865 ppb); 23-43 ppb nitrogen dioxide (1-h max: 208 ppb); 1.0-4.3 ppm carbon monoxide (8-h max: 7.1 ppm); 14-28 ppb sulfur dioxide (1-h max: 112 ppb); and 10-38 ppb ozone (1-h max: 72 ppb).
Previous studies have suggested that the presence of the vascular component of hand-arm vibration syndrome (HAVS) in the hands increases the risk of cold-induced vasospasm in the feet.
To determine if objectively measured cold-induced vasospasm in the hands is a risk factor for objectively measured cold-induced vasospasm in the feet in workers being assessed for HAVS.
The subjects were 191 male construction workers who had a standardized assessment for HAVS including cold provocation digital photocell plethysmography of the hands and feet to measure cold-induced vasospasm. Bivariate analysis and multinomial logistic regression were used to examine the association between plethysmographic findings in the feet and predictor variables including years worked in construction, occupation, current smoking, cold intolerance in the feet, the Stockholm vascular stage and plethysmographic findings in the hands.
Sixty-one (32%) subjects had non-severe vasospasm and 59 (31%) had severe vasospasm in the right foot with the corresponding values being 57(30%) and 62 (32%) in the left foot. Multinomial logistic regression indicated that the only statistically significant predictor of severe vasospasm in the feet was the presence of severe vasospasm in the hands (OR: 4.11, 95% CI: 1.60-10.6, P
The aim of this study was to investigate the association of noise sensitivity with self-reported hearing disability and hearing levels, with consideration of the role of self-reported history of noise exposure and use of hearing protectors. The study is based on the Finnish Twin Cohort. In 1988, a noise questionnaire was sent to 1005 twin pairs, 1495 individuals (688 men, 807 women) replied. The age range was 31-88 years. Information on some potential confounders was obtained from the questionnaire in 1981 for the same individuals. A subsample of thirty-eight elderly women with noise sensitivity response from 1988 had audiometry data from 2000 to 2001. Noise sensitivity was associated with self-reported hearing disability among all subjects [odds ratio (OR) 1.55, 95% confidence interval (CI) 1.14-2.12] and among women (OR 1.90, 95% CI 1.19-3.04), but no-more significantly among men (OR 1.31, 95% CI 0.86-1.98). The association was primarily seen among younger subjects (50 years or less). The difference between noise sensitive and non-noise sensitive elderly women in the average of thresholds at frequencies of 0.5-4 kHz in the better ear was not significant (Pr = 0.18). Noise sensitivity did not modify the association of hearing disability with the self-reported history of occupational noise exposure. Noise sensitivity was associated with the use of hearing protectors at work. The study shows the importance of recognizing the noise sensitive in noise effect studies, since sensitivity in annoyance has implications in most of the effect categories.
Studies of water-related gastrointestinal infections are usually directed at outbreaks. Few have examined endemic illness or compared rates across different water supply and sewage disposal systems. We conducted a cohort study of physician visits and hospitalizations for endemic intestinal infectious diseases in a mixed rural and urban community near Vancouver, Canada, with varied and well-characterized water and sewage systems.
Cohort members and their disease events were defined via universal health insurance data from 1995 through 2003. Environmental data were derived from municipal, provincial, and federal government sources. Logistic regression was used to examine associations between disease events and water and sewage systems, socio-demographic characteristics, and temporal factors.
The cohort included 126,499 individuals and approximately 190,000,000 person-days. Crude incidence rates were 1,353 physician visits and 33.8 hospitalizations for intestinal infectious diseases per 100,000 person-years. Water supply chlorination was associated with reduced physician visit incidence (OR: 0.92, 95% CI 0.85-1.0). Two water systems with the highest proportions of surface water had increased incidence (ORs: 1.57, 95% CI 1.39-1.78; and 1.45, 95% CI 1.28-1.64). Private well water and well depth were not associated with increased risk, likely because of residents' awareness of and attention to water quality. There was increased crude incidence with increasing precipitation in the population served by surface water supplies, but this trend did not remain with adjustment for other variables. Municipal sewer systems were associated with increased risk (OR: 1.26, 95% CI 1.14-1.38). Most socio-demographic variables had predicted associations with risk: higher rates in females, in the very young and the elderly, and in residents of low income areas. Increased duration of area residence was associated with reduced risk (OR, duration = 6 years: 0.69, 95% CI 0.60-0.80 vs.
The aim of this study is to examine whether the adoption of home smoking bans is associated with the physical and mental health of smokers. Two potential pathways that link home smoking bans to smoker's health are analyzed. The first argues that home smoking bans are positively related to physical health by encouraging smoking cessation while reducing daily cigarette consumption. The second suggests that home smoking bans have a negative relationship to smokers' mental health by increasing marginalization and social isolation.
Data on 28,887 Canadian smokers were analyzed from the Canadian Community Health Survey, a nationally representative sample of Canadians adults. Logistic regression models analyzed the impact of home smoking bans on subjective assessments of smoker's physical and mental health. Separate analyses were conducted on daily and occasional smokers, and additional analyses tested interactions between the presence of a home smoking ban and key socioeconomic (gender and low household income) and structural (dwelling ownership, living alone, and dwelling type) covariates.
Home smoking bans were not associated with smoker's physical health and were positively associated with smokers' mental health. These findings were consistent for daily smokers and occasional smokers. No significant interactions between smoking bans and socioeconomic or structural covariates were observed.
Findings are considered with respect to the internal and external constraints that shape smoker's behavior, particularly the influence of social norms around environmental tobacco smoke exposure and good citizenship and the role of family relationships. The implications of study findings are considered with respect to public health policy.
In temperate climates, invasive meningococcal disease (IMD) incidence tends to coincide with or closely follow peak incidence of influenza virus infection; at a seasonal level, increased influenza activity frequently correlates with increased seasonal risk of IMD.
We evaluated 240 cases of IMD reported in central Ontario, Canada, from 2000 to 2006. Associations between environmental and virological (influenza A, influenza B and respiratory syncytial virus (RSV)) exposures and IMD incidence were evaluated using negative binomial regression models controlling for seasonal oscillation. Acute effects of weekly respiratory virus activity on IMD risk were evaluated using a matched-period case-crossover design with random directionality of control selection. Effects were estimated using conditional logistic regression.
Multivariable negative binomial regression identified elevated IMD risk with increasing influenza A activity (per 100 case increase, incidence rate ratio?=?1.18, 95% confidence interval (CI): 1.06, 1.31). In case-crossover models, increasing weekly influenza A activity was associated with an acute increase in the risk of IMD (per 100 case increase, odds ratio (OR) ?=?2.03, 95% CI: 1.28 to 3.23). Increasing weekly RSV activity was associated with increased risk of IMD after adjusting for RSV activity in the previous 3 weeks (per 100 case increase, OR?=?4.31, 95% CI: 1.14, 16.32). No change in disease risk was seen with increasing influenza B activity.
We have identified an acute effect of influenza A and RSV activity on IMD risk. If confirmed, these finding suggest that influenza vaccination may have the indirect benefit of reducing IMD risk.
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This paper reports findings from a survey of 239 psychiatric nursing staff. This study aimed to investigate how often psychiatric nursing staff participates in clinical supervision and any possible associations among individual and workplace factors in relation to participation. The survey findings are followed by a prospective longitudinal registration of participants in clinical supervision. The registration revealed that participation varies considerably and large numbers of the staff may not participate in clinical supervision at all. Characteristics of the workplace, including organisational location, work shift, and work-environmental factors, are related to participation and, consequently, may affect the outcome of clinical supervision.
BACKGROUND: In the European Community Respiratory Health Survey (ECRHS) I, the lowest prevalence of asthma and atopy was found in Reykjavík (Iceland) and Tartu (Estonia). The aim of this study was to compare home environments in Reykjavík and Tartu to a town with a higher prevalence of asthma and atopy (Uppsala, Sweden) in an attempt to identify factors in the indoor environment that could explain these differences. METHOD: A random sample of 129 ECRHS II participants was included in this analysis at each of the three study centres. The subjects answered a questionnaire, blood was analysed for specific immunoglobulin E, a methacholine test was performed and home indoor measurements were taken. RESULTS: The prevalence of atopy was 11.9% in Reykjavík, 35.5% in Uppsala and 28.2% in Tartu (P
OBJECTIVES: To determine factors affecting the severity of motorcycle injuries, considering variables related to the individual, the environment, the vehicle, and the crash. METHODS: This is a register-based retrospective cohort study. All individuals born in 1970-1972 (n = 334,070) were extracted from the Swedish Population and Housing Census of 1985 and followed up from 1988 to 2000, when aged 16-30. All subjects whose records indicated an injury as a motorcycle driver in the Swedish National Road Administration Accident Database were selected, and constituted the study population (n = 1,748). Factors related to the individual, the environment, the vehicle, and the crash were considered as exposure measures, whereas the outcome measure was the level of injury severity, based on assessments made on-site by police officers, in two categories: fatal/severe and minor. Associations between individual, environmental, vehicle and crash factors and injury severity were measured, using Chi-square, and through univariate and multivariate stepwise logistic regression. RESULTS: Factors such as alcohol consumption, traffic environment, speed limit, and type of crash were significantly associated (p 1.0) with the likelihood of being severely injured. On modeling all the variables together through stepwise logistic regression, positive suspicion of alcohol emerged as the strongest determinant (adjusted OR = 2.7) of a severe outcome. CONCLUSIONS. Motorcycle crashes still place a heavy burden on young drivers. Increased efforts are needed to prevent alcohol-related crashes-through law enforcement and a multiplicity of policies at local and national levels.
This retrospective cohort study evaluated adverse birth outcomes in infants whose birth records indicated maternal residence in villages containing dumpsites potentially hazardous to health and environment. Birth records from 1997 to 2001 identified 10,073 eligible infants born to mothers in 197 Alaska Native villages. Outcomes included low or very low birth weight, preterm birth, and intrauterine growth retardation. Infants from mothers in villages with intermediate (odds ratio (OR) = 1.73, 95% confidence interval (CI): 1.06, 2.84) and high (OR = 2.06, 95% CI: 1.28, 3.32) hazard dumpsites had a higher proportion of low birth weight infants than did infants from mothers in the referent category. More infants born to mothers from intermediate (OR = 4.38, 95% CI: 2.20, 8.77) and high (OR = 3.98, 95% CI: 1.93, 8.21) hazard villages suffered from intrauterine growth retardation. On average, infants weighed 36 g less (95% CI: -71.2, -0.8) and 55.4 g less (95% CI: -95.3, -15.6) when born to highly exposed mothers than did infants in the intermediate and low exposure groups, respectively, an effect even larger in births to Alaska Native mothers only. No differences in incidence were detected across exposure levels for other outcomes. This is the first study to evaluate adverse pregnancy outcomes associated with open dumpsites in Alaska Native villages.
Northward expansion of the tick Ixodes scapularis is driving Lyme disease (LD) emergence in Canada. Information on mechanisms involved is needed to enhance surveillance and identify where LD risk is emerging.
We used passive and active surveillance and phylogeographic analysis of Borrelia burgdorferi to investigate LD risk emergence in Quebec.
In active surveillance, we collected ticks from the environment and from captured rodents. B. burgdorferi transmission was detected by serological analysis of rodents and by polymerase chain reaction assays of ticks. Spatiotemporal trends in passive surveillance data assisted interpretation of active surveillance. Multilocus sequence typing (MLST) of B. burgdorferi in ticks identified likely source locations of B. burgdorferi.
In active surveillance, we found I. scapularis at 55% of sites, and we were more likely to find them at sites with a warmer climate. B. burgdorferi was identified at 13 I. scapularis-positive sites, but infection prevalence in ticks and animal hosts was low. Low infection prevalence in ticks submitted in passive surveillance after 2004-from the tick-positive regions identified in active surveillance-coincided with an exponential increase in tick submissions during this time. MLST analysis suggested recent introduction of B. burgdorferi from the northeastern United States.
These data are consistent with I. scapularis ticks dispersed from the United States by migratory birds, founding populations where the climate is warmest, and then establishment of B. burgdorferi from the United States several years after I. scapularis have established. These observations provide vital information for public health to minimize the impact of LD in Canada.
Cites: Am J Trop Med Hyg. 1988 Jul;39(1):105-93400797
The Norwegian Mother and Child Cohort Study (MoBa) started in 1999 to identify environmental factors that could be involved in mechanisms leading to disease. Questions have been raised about potential risks to the fetus from prenatal exposure to mercury from amalgam fillings in pregnant women. The aim of the present study was to identify factors potentially associated with amalgam fillings in pregnant women participating in the Norwegian Mother and Child Cohort Study (MoBa). An additional aim was to obtain information about dental treatment in the cohort.
Total of 67,355 pregnancies from the MoBa study were included in the present study. Information regarding age, education, smoking habits, alcohol consumption, weight, and height for the women was obtained from a questionnaire that was filled in at the 17th week of pregnancy. In another questionnaire, which was sent to all participants in the 30th week of pregnancy, the women reported types of dental treatment during pregnancy, total number of teeth, and number of teeth with amalgam fillings. The self-assessed number of teeth and number of teeth with amalgam fillings were validated in an external sample of 97 women of childbearing age.
Odds ratio for having more than 12 teeth with amalgam fillings increased considerably with age. Other significant risk factors for having high exposure to amalgam were low education, high body mass index (BMI), and smoking during pregnancy. Women with the lowest levels of education had a twofold increased odds ratio of having more than 12 teeth filled with amalgam compared with women who had more than 4 years of university studies. According to the results from the validation of self-assessed number of teeth with amalgam fillings, the information obtained was reliable.
Age, education, smoking habits, and BMI were associated with amalgam exposure.
Comment In: J Evid Based Dent Pract. 2011 Sep;11(3):162-321855822
Baseline data from the Canadian National Longitudinal Survey of Children and Youth (NLSCY, a population-based study of child health, development and well-being), were used to determine biological, social and environmental correlates of poor development among preschool children. A total weighted sample of 1233 500 (n = 6982 unweighted) children aged from birth to 3 years were studied. Developmental attainment was measured by the motor, social and development (MSD) scale. Children scoring amongst the lowest 15% for their age group were categorized as having poor developmental attainment (PDA). Correlates of PDA were determined using logistic regression. The MSD scale may not be discriminatory enough to identify PDA in children aged
Environmental factors are needed to explain the observed increase in the prevalence of asthma during recent decades, despite the existence of a recognised genetic component in asthma. A co-twin case-control study was undertaken to examine possible social risk factors for asthma.
Asthma diagnoses were based on register data of reimbursed asthma medication. During 17 years follow up of the Finnish twin cohort, 262 twin pairs discordant for incident asthma were identified. Conditional logistic regression for 1-1 matched data was used for risk calculation.
The atopic twin had an increased risk of asthma compared with the non-atopic co-twin (RR 2.91, 95% CI 1.81 to 4.68). The more educated twin had a decreased risk of asthma compared with his/her twin sibling with less education (RR 0.45, 95% CI 0.23 to 0.86), and the twin who participated in conditioning exercise had a decreased risk of asthma compared with the more sedentary co-twin (RR 0.55, 95% CI 0.34 to 0.88).
In addition to allergic diseases, educational level and physical activity are associated with adult onset asthma, which indicates a role for factors associated with life style.
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Although some consensus has emerged among the scientific and regulatory communities that the urban ambient atmospheric mix of combustion related pollutants is a determinant of population health, the relative toxicity of the chemical and physical components of this complex mixture remains unclear. Daily mortality rates and concurrent data on size-fractionated particulate mass and gaseous pollutants were obtained in eight of Canada's largest cities from 1986 to 1996 inclusive in order to examine the relative toxicity of the components of the mixture of ambient air pollutants to which Canadians are exposed. Positive and statistically significant associations were observed between daily variations in both gas- and particulate-phase pollution and daily fluctuations in mortality rates. The association between air pollution and mortality could not be explained by temporal variation in either mortality rates or weather factors. Fine particulate mass (less than 2.5 microns in average aerometric diameter) was a stronger predictor of mortality than coarse mass (between 2.5 and 10 microns). Size-fractionated particulate mass explained 28% of the total health effect of the mixture, with the remaining effects accounted for by the gases. Forty-seven elemental concentrations were obtained for the fine and coarse fraction using nondestructive x-ray fluorescence techniques. Sulfate concentrations were obtained by ion chromatography. Sulfate ion, iron, nickel, and zinc from the fine fraction were most strongly associated with mortality. The total effect of these four components was greater than that for fine mass alone, suggesting that the characteristics of the complex chemical mixture in the fine fraction may be a better predictor of mortality than mass alone. However, the variation in the effects of the constituents of the fine fraction between cities was greater than the variation in the mass effect, implying that there are additional toxic components of fine particulate matter not examined in this study whose concentrations and effects vary between locations. One of these components, carbon, represents half the mass of fine particulate matter. We recommend that measurements of elemental and organic carbon be undertaken in Canadian urban environments to examine their potential effects on human health.
OBJECTIVE: To study the effects of ventilation and temperature changes in computer classrooms on symptoms in students. METHODS: Technical university students participated in a blinded study. Two classrooms had higher air exchange (4.1-5.2 ac/h); two others had lower (2.3-2.6 ac/h) air exchange. After 1 week, ventilation conditions were interchanged between the rooms. The students reported symptoms during the last hour, on a seven-step rating scale. Room temperature, relative air humidity (RH) carbon dioxide (CO(2)), PM10 and ultra-fine particles (UFP) were measured simultaneously (1 h). Illumination, air velocity, operative temperature, supply air temperature, formaldehyde, NO(2) and O(3) were measured. Multiple logistic regression was applied in cross-sectional analysis of the first answer (N = 355). Those participating twice (N = 121) were analysed longitudinally. RESULTS: Totally 31% were females, 2.9% smokers and 3.8% had asthma. Mean CO(2) was 993 ppm (674-1,450 ppm), temperature 22.7 degrees C (20-25 degrees C) and RH 24% (19-35%). Lower and higher air exchange rates corresponded to a personal outdoor airflow of 7 l/s*p and 10-13 L/s*P, respectively. Mean PM10 was 20 microg/m(3) at lower and 15 microg/m(3) at higher ventilation flow. Ocular, nasal and throat symptoms, breathlessness, headache and tiredness were significantly more common at higher CO(2) and temperature. After mutual adjustment, ocular (OR = 1.52 per 1 degrees C), nasal (OR = 1.62 per 1 degrees C) and throat symptoms (OR = 1.53 per 1 degrees C), headache (OR = 1.51 per 1 degrees C) and tiredness (OR = 1.54 per 1 degrees C) were significantly associated with temperature; headache was associated only with CO(2) (OR = 1.19 per 100 ppm CO(2)). Longitudinal analysis demonstrated that increased room temperature was related to tiredness (P