Pesticide exposures and immune suppression have been independently associated with the risk of non-Hodgkin lymphoma (NHL), but their joint effect has not been well explored. Data from a case-control study of men from six Canadian provinces were used to evaluate the potential effect modification of asthma, allergies, or asthma and allergies and hay fever combined on NHL risk from use of: (i) any pesticide; (ii) any organochlorine insecticide; (iii) any organophosphate insecticide; (iv) any phenoxy herbicide; (v) selected individual pesticides [1,1'-(2,2,2-trichloroethylidene)bis[4-chlorobenzene]; 1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane (DDT), malathion, (4-chloro-2-methylphenoxy)acetic acid (MCPA), mecoprop, and (2,4-dichlorophenoxy)acetic acid (2,4-D); and (vi) from the number of potentially carcinogenic pesticides. Incident NHL cases (n = 513) diagnosed between 1991 and 1994 were recruited from provincial cancer registries and hospitalization records and compared to 1,506 controls. A stratified analysis was conducted to calculate odds ratios (ORs) adjusted for age, province, proxy respondent, and diesel oil exposure. Subjects with asthma, allergies, or hay fever had non-significantly elevated risks of NHL associated with use of MCPA (OR = 2.67, 95% confidence interval [CI]: 0.90-7.93) compared to subjects without any of these conditions (OR = 0.81, 95% CI: 0.39-1.70). Conversely, those with asthma, allergies, or hay fever who reported use of malathion had lower risks of NHL (OR = 1.25, 95% CI: 0.69-2.26) versus subjects with none of these conditions (OR = 2.44, 95% CI: 1.65-3.61). Similar effects were observed for asthma and allergies evaluated individually. Although there were some leads regarding effect modification by these immunologic conditions on the association between pesticide use and NHL, small numbers, measurement error and possible recall bias limit interpretation of these results.
It is often taken for granted that an ageing population will lead to an increased burden for the health care sector. However, for several diseases of big public health impact the rates have actually come down for a substantial period of time. In this study we investigate how much the incidence rates for myocardial infarction (MI), stroke, and cancer will have to decline in order to counterbalance future demographic changes (changes in population size and age structure) and compare these figures with observed historical trends. Information on incidence rates were obtained from the National Board of Health and Welfare and referred to the total Swedish population. Population projections were obtained from Statistics Sweden. We projected the number of MI events to increase 50-60% between 2010 and 2050. The decline in incidence rates that is required to keep the number of events constant over time is, on average, 1.2%/year for men and 0.9%/year for women, somewhat higher than the trend for the past 10 years. For stroke the corresponding figures were 1.3% (men) and 1% (women), well in line with historical trends. For cancer the results indicate an increasing number of events in the future. Population ageing is more important than population growth when projecting future number of MI, stroke and cancer events. The required changes in incidence rates in order to counterbalance the demographic changes are well in line with historical figures for stroke, almost in line regarding MI, but not in line regarding cancer. For diseases with age dependence similar to these diseases, a reduction of incidence rates in the order of 1-2% is sufficient to offset the challenges of the ageing population. These are changes that have been observed for several diseases indicating that the challenges posed by the ageing population may not be as severe as they may seem when considering the demographic component alone.
In a Swedish population-based case-control study (1571 cases, 3371 controls), subjects with different body mass indices (BMIs) were compared regarding multiple sclerosis (MS) risk, by calculating odds ratios (OR) with 95% confidence intervals (95% CI). Subjects whose BMI exceeded 27 kg/m(2) at age 20 had a two-fold increased risk of developing MS compared with normal weight subjects. Speculatively, the obesity epidemic may explain part of the increasing MS incidence as recorded in some countries. Measures taken against adolescent obesity may thus be a preventive strategy against MS.
The paper analyzes the clinical and laboratory features of Lamblia infection in children living under long-term low-dose chemical load. The scientific search methodology comprised the meticulous examination of the patients randomized by the presence or absence of protozoonosis and the statistical processing and expert analysis of the results. The comprehensive approach could define the main signs of the pathomorphism of lambliosis in the areas with high anthropogenic loads and identify immunological disorders, intoxication, and hepatobiliary dysfunctions. The impact of environmentally induced chemical contamination of the biosphere on the natural history of protozoonosis should be borne in mind when evaluating the biological hazard and risk of environmental biological factors on the population health and when scheduling and implementing hygienic and sanitary-and-epidemiological measures to prevent lambliosis in the high anthropogenic load areas.
In Ontario, there are significant geographical disparities in colorectal cancer incidence. In particular, the northern region of Timiskaming has the highest incidence of colorectal cancer in Ontario while the southern region of Peel displays the lowest. We aimed to identify non-nutritional modifiable environmental factors in Timiskaming that may be associated with its diverging colorectal cancer incidence rates when compared to Peel.
We performed a systematic review to identify established and proposed environmental factors associated with colorectal cancer incidence, created an assessment questionnaire tool regarding these environmental exposures, and applied this questionnaire among 114 participants from the communities of Timiskaming and Peel.
We found that tobacco smoking, alcohol consumption, residential use of organochlorine pesticides, and potential exposure to toxic metals were dominant factors among Timiskaming respondents. We found significant differences regarding active smoking, chronic alcohol use, reported indoor and outdoor household pesticide use, and gold and silver mining in the Timiskaming region.
This study, the first to assess environmental factors in the Timiskaming community, identified higher reported exposures to tobacco, alcohol, pesticides, and mining in Timiskaming when compared with Peel. These significant findings highlight the need for specific public health assessments and interventions regarding community environmental exposures.
Department of Epidemiology Research, Statens Serum Institut, Department of Occupational and Environmental Medicine, Bispebjerg Hospital and Department of Rheumatology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.Department of Epidemiology Research, Statens Serum Institut, Department of Occupational and Environmental Medicine, Bispebjerg Hospital and Department of Rheumatology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark. firstname.lastname@example.org.
This study assessed the suggested association between pregnancy-associated hypertensive disorders, hyperemesis and subsequent risk of RA using a cohort with information about pre-pregnancy health.
Self-reported information on pre-pregnancy health, pregnancy course, gestational hypertension, pre-eclampsia and hyperemesis was available from 55 752 pregnant women included in the Danish National Birth Cohort. Information about pregnancy-related factors and lifestyle was obtained by interviews twice during pregnancy and at 6 months post-partum. Women were followed for RA hospitalizations identified in the Danish National Patient Register. Hazard ratios (HRs) and 95% CIs were calculated using Cox proportional hazards models. Women with RA and non-specific musculoskeletal problems at the time of pregnancy were excluded.
On average, women were followed for 11 years after childbirth and 169 cases of RA were identified. The risk of RA was increased in women with pre-eclampsia (n = 11, HR = 1.96, 95% CI 1.06, 3.63), a poor self-rated pregnancy course (n = 32, HR = 1.63, 95% CI 1.11, 2.39) and fair or poor self-rated pre-pregnancy health (fair health: n = 86, HR = 1.52, 95% CI 1.11, 2.09; poor health: n = 14, HR = 3.24, 95% CI 1.82, 5.76). Hyperemesis was not associated with risk of RA.
We confirmed the previously suggested increased risk of RA in women with pre-eclampsia and also found an inverse association between self-rated pre-pregnancy health and risk of RA. These results suggest that the clinical onset of RA is preceded by a prolonged subclinical phase that may interfere with women's general well-being and pregnancy course or that some women carry a shared predisposition to pre-eclampsia and RA.
Acute gastro-intestinal illness (AGI) is a major cause of mortality and morbidity worldwide and an important public health problem. Despite the fact that AGI is currently responsible for a huge burden of disease throughout the world, important knowledge gaps exist in terms of its epidemiology. Specifically, an understanding of seasonality and those factors driving seasonal variation remain elusive. This paper aims to assess variation in the incidence of AGI in British Columbia (BC), Canada over an 11-year study period. We assessed variation in AGI dynamics in general, and disaggregated by hydroclimatic regime and drinking water source. We used several different visual and statistical techniques to describe and characterize seasonal and annual patterns in AGI incidence over time. Our results consistently illustrate marked seasonal patterns; seasonality remains when the dataset is disaggregated by hydroclimatic regime and drinking water source; however, differences in the magnitude and timing of the peaks and troughs are noted. We conclude that systematic descriptions of infectious illness dynamics over time is a valuable tool for informing disease prevention strategies and generating hypotheses to guide future research in an era of global environmental change.
The effect of an 18.5-week infantry training program on health status was studied in 23 male military personnel (aged 22.0 +/- 0.5 years, mean +/- SE). Aerobic power, body composition, and immune function (including natural killer cell activity, mitogen-stimulated lymphocyte proliferation, in vivo cell-mediated immunity, and secretory immunoglobulin A levels) were measured in subjects at the beginning and end of the course. Subjects self-reported their symptoms of sickness in health logs using a precoded checklist. Data from this study indicate that subjects became leaner and maintained, but did not increase, their aerobic fitness by the end of the course. Cell function was enhanced significantly; however, in vivo cell-mediated immunity remained the same, and levels of secretory immunoglobulin A were lower by the end of the course. The incidence of infection remained stable throughout the course. These results indicate that the current pattern of infantry training does not have an adverse effect on the health status of recruits.
The association between exposure to ambient air nitrogen dioxide and cough was evaluated in a panel study among 162 children aged 3-6 y. The weekly average nitrogen dioxide exposure was assessed with Palmes-tube measurements in three ways: (1) personally, (2) outside day-care centers, and (3) inside day-care centers. Ambient air nitrogen dioxide concentrations were obtained from the local network that monitored air quality. The parents recorded cough episodes daily in a diary. The risk of cough increased significantly (relative risk = 3.63; 95% confidence interval = 1.41, 9.30) in the highest personal nitrogen dioxide exposure category in winter, and a nonsignificant positive trend was noted for the other assessment groups. In spring, risk increased nonsignificantly in all exposure-assessment groups, except for the fixed-site monitoring assessment. It is important that investigators select an exposure-assessment method sufficiently accurate to reflect the effective pollutant dose in subjects.
Air contamination in sawmills can cause respiratory health problems. The authors measured respirable dust, bacteria, endotoxins, and molds collected from 17 sawmills in eastern Canada. A total of 1,205 sawmill workers answered a respiratory-health questionnaire, and they all participated in lung-function measurements, skin-prick tests, and venous blood sampling for specific immunoglobulins against molds found in the sawmills. Workers had normal lung functions, and most respiratory symptoms could be explained by smoking histories. Workers in pine sawmills had a greater prevalence of positive skin-prick test to pine than did workers in sawmills where other woods were used. High levels of specific antibodies were seen in some workers. The presence of a positive skin-prick test and/or specific antibodies had no impact on lung function(s). These Quebec sawmill workers did not experience significant respiratory illnesses; however, some of these workers may be at a higher risk of developing asthma and hypersensitivity pneumonitis than nonworkers.
Department of Clinical and Experimental Medicine, Occupational and Environmental Medicine, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden (Nyqvist, Helmfrid, Dr Wingren); and Department of Biology and Environmental Science, Faculty of Health and Life Sciences, Linneaus University, Kalmar, Sweden (Dr Augustsson).
The aim of this study was to examine mortality causes and cancer incidence in a population cohort that have resided in close proximity to highly metal-contaminated sources, characterized by contamination of, in particular, arsenic (As), cadmium (Cd), and lead (Pb).
Data from Swedish registers were used to calculate standardized mortality and cancer incidence ratios. An attempt to relate cancer incidence to metal contamination levels was made.
Significantly elevated cancer incidences were observed for overall malignant cancers in both genders, cancer in the digestive system, including colon, rectum, and pancreas, and cancers in prostate among men. Dose-response relationships between Cd and Pb levels in soil and cancer risks were found.
Cancer observations made, together with previous studies of metal uptake in local vegetables, may imply that exposure to local residents have occurred primarily via oral intake of locally produced foodstuffs.
This paper applies a method for modelling the spatial variation of West Nile virus (WNv) in humans using bird, environmental and human testing data.
We used data collected from 503 Alberta municipalities. In order to manage the effects of residual spatial autocorrelation, we used generalized linear mixed models (GLMM) to model the incidence of infection.
There were 275 confirmed cases of WNv in the 2003 calendar year in Alberta. Our spatial model indicates that living in the grasslands natural region and levels of human testing are significant positive predictors of WNv; living in an urban area is a significant negative predictor.
Infected bird data contribute little to our model. The variability of West Nile virus incidence in Alberta may be partly confounded by the variations in the rate of testing in different parts of the province. However, variation in infection is also associated with known environmental risk factors. Our findings are consistent with existing knowledge of WNv in North America.
A statistically significant direct strong correlation was found between the annual average daily concentrations of air benz[a]pyrene and the lung and the gastric cancer morbidity rates in males and females, skin, thyroid, and ovarian cancer in females. The certain interval of the measured concentration of benz[a]pyrene and the recorded morbidity rate was shown to be characteristic of each of the above-mentioned tumors.
Incidence of multiple sclerosis is thought to be increasing, but this notion has been difficult to substantiate. In a longitudinal population-based dataset of patients with multiple sclerosis obtained over more than three decades, we did not show a difference in time to diagnosis by sex. We reasoned that if a sex-specific change in incidence was occurring, the female to male sex ratio would serve as a surrogate of incidence change.
Since environmental risk factors seem to act early in life, we calculated sex ratios by birth year in 27 074 Canadian patients with multiple sclerosis identified as part of a longitudinal population-based dataset.
The female to male sex ratio by year of birth has been increasing for at least 50 years and now exceeds 3.2:1 in Canada. Year of birth was a significant predictor for sex ratio (p
Fiber dimension and concentration may vary substantially between two necropsy populations of former chrysotile miners and millers of Thetford-Mines and Asbestos regions. This possibility could explain, at least in part, the higher incidence of respiratory diseases among workers from Thetford-Mines than among workers from the Asbestos region. The authors used a transmission electron microscope, equipped with an x-ray energy-dispersive spectrometer, to analyze lung mineral fibers of 86 subjects from the two mining regions and to classify fiber sizes into three categories. The most consistent difference was the higher concentration of tremolite in lung tissues of workers from Thetford-Mines, compared with workers from the Asbestos region. Amosite and crocidolite were also detected in lung tissues of several workers from the Asbestos region. No consistent and biologically important difference was found for fiber dimension; therefore, fiber dimension does not seem to be a factor that accounts for the difference in incidence of respiratory diseases between the two groups. The greater incidence of respiratory diseases among workers of Thetford-Mines can be explained by the fact that they had greater exposure to fibers than did workers at the Asbestos region. Among the mineral fibers studied, retention of tremolite fibers was most apparent.
To analyse incidence of sickness for women and men relative to potential aetiological factors at work-physical, psychosocial, and organisational.
The study group comprised 1557 female and 1913 male employees of Sweden Post. Sickness absence was measured by incidence of sickness (sick leave events and person-days at risk). Information on explanatory factors was obtained by a postal questionnaire, and incidence of sickness was based on administrative files of the company.
Complaints about heavy lifting and monotonous movements were associated with increased risk of high incidence of sickness among both women and men. For heavy lifting, an odds ratio (OR) of 1.70 (95% confidence interval (95% CI) 1.22 to 2.39) among women, and OR 1.70 (1.20 to 2.41) among men was found. For monotonous movements the risk estimates were OR 1.42 (1.03 to 1.97) and OR 1.45 (1.08 to 1.95) for women and men, respectively. Working instead of taking sick leave when ill, was more prevalent in the group with a high incidence of sickness (OR 1.74 (1.30 to 2.33) for women, OR 1.60 (1.22 to 2.10) for men). Overtime work of more than 50 hours a year was linked with low incidence of sickness for women and men. Among women, 16% reported bullying at the workplace, which was linked with a doubled risk of high incidence of sickness (OR 1.91 (1.31 to 2.77)). For men, the strongest association was found for those reporting anxiety about reorganisation of the workplace (OR 1.93 (1.34 to 2.77)).
Certain physical, psychosocial, and organisational factors were important determinants of incidence of sickness, independently of each other. Some of the associations were sex specific.