Seasonal changes in lung function in a farming population.

OBJECTIVE: To assess the changes in respiratory health from winter to summer seasons in a rural population. DESIGN: A longitudinal design was used in the study. SETTING: A population-based study was conducted as part of the Environmental Pesticide Exposure and Human Health component of the Prairie Ecosystem Study (PECOS) in southwestern Saskatchewan. PATIENTS: In the winter season, 358 patients participated in the study. Of these patients, 234 returned for the second assessment during the summer season. After excluding 34 children aged 17 years and under, 200 adult patients were available for analysis. MEASUREMENTS: Questionnaires were used to obtain information on demographic factors, smoking habits, occupational and environmental exposures, and respiratory conditions. Pulmonary function measurements were obtained using a volume displacement spirometer. RESULTS: Mean ages (+/- SD) of the 106 men and 94 women participating in the study were 50.1+/-13.3 and 49.0+/-13.1 years, respectively. Mean percentage changes in maximal midexpiratory flow rate from winter to summer assessments indicated an improvement for town residents and a decline for farm residents. Mean percentage changes in the ratio of forced expiratory volume in 1 s to forced vital capacity indicated an improvement for town residents who were not engaged in farming, and increasing declines for town residents engaged in farming, farm residents not engaged in farming and farm residents engaged in farming. CONCLUSIONS: Seasonal changes occurred in measurements of pulmonary function between winter and summer seasons; these changes may be related to the environmental or occupational exposures experienced by the participants during the study.

Health and environment of rural families: results of a Community Canvass survey in the Prairie Ecosystem Study (PECOS).

This cross-sectional survey was conducted as Phase I of the Prairie Ecosystem Study (PECOS): Environmental Pesticide Exposure and Human Health. In November of 1995, community volunteers delivered a self-administered household questionnaire to 1185 rural households in southern Saskatchewan, Canada. The survey provided a broad description of the general health and the physical environment of 511 men, 499 women, and 393 children (< 18 years of age) residing in 549 respondent households in the rural study area (population density of about one person/km2). Families in the respondent households resided on a farm, in town or both. Of the 369 households that operated a farm, 25.2% of the households did not list the farm as their primary household. Residents of both farming and non-farming households reported contact with pesticides and fertilizers through home or garden use. History of smoking was greater among men and women from non-farming households. The most commonly reported health problems among the children were a history of bronchitis, asthma, skin allergies, pneumonia, and hay fever. The most frequently reported health problems among the men were a history of high blood pressure, bronchitis, pneumonia, hearing problems, and stress; and among the women were a history of bronchitis, high blood pressure, shortness of breath, and pneumonia. Compared to farming households, more members of non-farming households reported a history of respiratory problems, particularly bronchitis among the women and children. Overall, there were important differences in the smoking history, the occupational use of pesticides and fertilizers, and the general health status between the farming and non-farming households and individuals in this rural population.

Prevalence of antinuclear antibodies in a rural population.

Exposure to environmentally and occupationally encountered toxicants can be associated with the development of certain autoimmune diseases and with the induction of antinuclear antibodies (ANA). Some chemicals used in the agricultural industry are known to affect immune function but their roles in the induction of autoimmunity in general, and ANA in particular, have not been reported previously. This study was undertaken to establish the prevalence of ANA in a rural population and to determine environmental and occupational exposures with which they are associated. This cross-sectional study represented one component of an interdisciplinary project (Prairie Ecosystem Study [PECOS], Eco-Research Program, Tri-Council Secretariat of Canada) designed to explore, in a rural population, the roles of environmental exposures as determinants of human health status. Information regarding lifetime, current, and main occupational exposures in the rural-dwelling study population was derived from a self-administered questionnaire. Sera from consenting subjects, collected during the months of February and March 1996, were assayed for ANA by indirect immunofluorescence on HEp-2 cells. The study population comprised 322 adult subjects (mean age 49.3+/-14.7 yr; range 16-87 yr). Statistical analyses adjusted for age and sex revealed that the presence of ANA among the participants was associated with a current agricultural occupation that included oilseed production, hog production, or poultry production. There was a significant association between ANA positivity and a current main farming operation of crop production. There was also an association among individual participants between lifetime exposure to the insecticide class of pesticides and the presence of ANA. In this rural study population, ANA positivity was significantly associated with lifetime exposure specifically to carbamate, organochlorine (including aldrin, chlordane, dieldrin, endrin, heptachlor, and lindane, but excluding DDT and methoxychlor), and pyrethroid insecticides and to phenoxyacetic acid herbicides, including 2,4-D. After adjustment for age, sex, and other insecticide exposures, multivariate analyses indicated that ANA positivity was associated with current oilseed production and with lifetime exposure to pyrethroid insecticides. In a rural population, ANA were associated with production of certain crops and certain animals and exposure to specific pesticides. The data indicate that some occupational exposures related to the agricultural industry are associated with the presence of ANA, a serologic expression of autoimmunity.

Effects of agricultural work and other proxy-derived case-control data on Parkinson's disease risk estimates.

This study examined the effects on Parkinson's disease risk estimates of exposure misclassification in proxy-derived data on agricultural work, pesticide use, rural living, well water drinking, head trauma, smoking, and family history of Parkinson's disease or essential tremor. The data were collected in 1989 as part of a population-based case-control study of Parkinson's disease in Calgary, Canada. Nondemented cases (n = 130) were selected from a case register of Calgary residents with neurologist-confirmed Parkinson's disease. For each case, two matched (sex and age +/- 2.5 years) community controls were selected by random digit dialing. Forty cases and 77 controls were randomly selected as index respondents. The cases, controls, and one proxy respondent (spouse or offspring) for each index respondent were interviewed using a structured questionnaire. The data were analyzed using conditional logistic regression. Incorporation of proxy-derived data for 30% of the cases or controls, or both, resulted in considerable misclassification of exposure for some variables and, in most cases, attenuation of the odds ratio. The results indicate that pooling dichotomously classified data derived in part from self- and proxy respondents may result in biased estimates of Parkinson's disease risk associated with agricultural, family history, and head trauma factors.

Reliability of environmental and occupational exposure data provided by surrogate respondents in a case-control study of Parkinson's disease.

This study used data provided by 40 non-demented Parkinson's disease patients and 101 community controls, and by their 110 spouses and 31 adult children to assess the reliability of surrogate-provided rural environmental and occupational exposure information on the index subjects. The level of overall raw agreement between the index subjects and the spouse or adult child surrogates varied from 50.0 to 100.0% for the case-surrogate group and from 80.6 to 96.0% for the control-surrogate group. We did not detect significant differences in overall raw agreement between the case-surrogate and control-surrogate groups or between the spouse-surrogate and adult child-surrogate groups, for any of the variables studied. Considering all index subjects and their surrogates, the level of overall raw agreement was 80.3% for well water consumption, 82.3% for farm living, 85.8% for agricultural work, 87.1% for use of pesticides, 87.9% for field crop farming and 91.9% for use of fertilizers. However, the kappa estimates were lower, varying from 0.48 (SE = 0.20) for fertilizer use to 0.66 (SE = 0.11) for crop farming. The level of specific agreement was 52.2% for fertilizer use, 64.0% for pesticide use, 71.4% for agricultural work, 73.9% for crop farming, 80.9% for farm living, and 83.6% for well water consumption. The overall findings of this study support the use, if necessary, of spouses and adult children of index subjects as surrogate respondents in case-control studies of rural environment and occupational exposures and Parkinson's disease and, possibly, other neurologic diseases. Specific agreement seems to be a better index of reliability than overall agreement in studies where exposure is rare.

Parkinson's disease: a test of the multifactorial etiologic hypothesis.

We studied the relative etiologic importance upon the development of Parkinson's disease (PD) of occupational exposure to herbicides and other compounds, ionizing radiation exposure, family history of PD and essential tremor, smoking, and history of various viral and other medical conditions. We identified patients (n = 130) with neurologist-confirmed idiopathic PD through contacts with Calgary general hospitals, long-term care facilities, neurologists, the Movement Disorder Clinic, and the Parkinson's Society of Southern Alberta, and selected two matched (by sex and age +/- 2.5 years) community controls for each case by random digit dialing. We obtained lifetime work, chemical, radiation, medical, and smoking exposure histories and family histories of PD and essential tremor by personal interviews, and analyzed the data using conditional logistic regression for matched sets. After controlling for potential confounding and interaction between the exposure variables, using multivariate statistical methods, having a family history of PD was the strongest predictor of PD risk, followed by head trauma and then occupational herbicide use. Cases and controls did not differ in their previous exposures to smoking or ionizing radiation; family history of essential tremor; work-related contact with aluminum, carbon monoxide, cyanide, manganese, mercury, or mineral oils; or history of arteriosclerosis, chicken pox, encephalitis, hypertension, hypotension, measles, mumps, rubella, or Spanish flu. These results support the hypothesis of a multifactorial etiology for PD, probably involving genetic, environmental, trauma, and possibly other factors.

An assessment of the usefulness of demographic data provided by surrogate respondents in a case-control study of Parkinson's disease.

This study, based upon data from 40 non-demented Parkinson's disease cases and 101 community controls, and similar data provided by either the spouse (n = 110) or an adult child (n = 31) of each index subject, attempted to assess the usefulness of various demographic data provided by the surrogate respondents for the index subjects. The data were collected by personal interview using a structured questionnaire specifically developed for this study. Ninety-one percent of the index subjects and their surrogates provided information on the annual family income and 98% provided other demographic information. The analysis was done by three groups: the case-surrogates, the control-surrogates and the combined index subject-surrogates, and within each group by the two types of surrogates for the index subjects: the spouse vs adult child. The overall percent agreement between the index subjects and their surrogates varied from moderate for annual family income (54.1%), to good for educational level (61.6%) and to excellent for ethnic origin (82.6%), for age +/- 1 year (97.9%) and for marital status (100.0%). No significant differences in agreement were found for any of these demographic variables either between the case-surrogate group and the control-surrogate group, or between the spouse surrogates and the child surrogates. These findings suggest that spouses and adult children can provide valid information and are equally reliable informants concerning the demographic characteristics of index subjects in a case-control study of Parkinson's disease and, possibly, of other diseases.

Parkinson's disease and exposure to agricultural work and pesticide chemicals.

This population-based case-control study of 130 Calgary residents with neurologist-confirmed idiopathic Parkinson's disease (PD) and 260 randomly selected age- and sex-matched community controls attempted to determine whether agricultural work or the occupational use of pesticide chemicals is associated with an increased risk for PD. We obtained by personal interviews lifetime occupational histories, including chemical exposure data, and analyzed the data using conditional logistic regression for matched sets. In the univariate analysis, a history of field crop farming, grain farming, herbicide use, or insecticide use resulted in a significantly increased crude estimate of the PD risk, and the data suggested a dose-response relation between the PD risk and the cumulative lifetime exposure to field crop farming and to grain farming. However, in the multivariate analysis, which controlled for potential confounding or interaction between the exposure variables, previous occupational herbicide use was consistently the only significant predictor of PD risk. These results support the hypothesis that the occupational use of herbicides is associated with an increased risk for PD.

Parkinson's disease and exposure to rural environmental factors: a population based case-control study.

To determine whether a history of exposure to rural environmental factors leads to an increased likelihood of developing idiopathic Parkinson's disease, we conducted a case-control study of 130 cases and 260 randomly selected community controls (matched with the cases by sex and age +/- 2.5 years at a ratio of 2 controls: 1 case) in the city of Calgary. The data were collected by personal interviews and were analyzed using conditional logistic regression for matched sets. The ages of the cases ranged from 36.5 to 90.7 years (mean = 68.5 +/- 11.3 years). The mean age at diagnosis was 61.1 +/- 12.4 years. The mean duration of disease was 7.8 +/- 0.6 years. Eleven (9.1%) cases were diagnosed before age 40. In this sample from the Province of Alberta, Canada, no significant increase in risk for Parkinson's disease was associated with a history of rural living, farm living, or well water drinking in early childhood or at any time during the first 45 years of life.

Children's health and illness behaviour: the single working mother's perspective.

This study explored how single working mothers perceive and deal with concerns about their children's health. "Grounded theory" analysis of data from interviews with single mothers in a wide variety of circumstances suggested that contextual factors including the mother's work situation, child care and social network are important to understanding the health and illness behaviour of these families. Children's use of health services appeared to reflect the single mother's attempts to manage her roles as mother (nurturer) and worker (provider), and her sense of role flexibility. A sense of flexibility appeared to mitigate role conflict and to interact with other known influences of health services utilization including the quality of the client/practitioner relationship. The mother's sense of flexibility appeared to vary with her income, child care arrangement, work situation (e.g., emphathetic supervisor), access to tangible support (e.g., child care) and social network (i.e., proximity to her family of origin).

The effect of stressful life events on EMG biofeedback and relaxation training in the treatment of anxiety.

The present study evaluated the effect of frontal EMG biofeedback and relaxation training on a group of 20 anxious patients experiencing stressful life events. The patients were divided into two groups, high and low in stress, based on their life change score on the Recent Life Changes Questionnaire. Patients were evaluated at pre, post, and 6-week follow-up. Treatment consisted of 10 sessions of biofeedback-assisted relaxation. Results indicated that the high stress group showed pre to post changes on anxiety, depression, symptoms, and EMG, while low stress showed no change. Post to follow-up comparisons showed maintenance of improvement for the high stress group and no change for low stress. From pre to follow-up assessment, the high stress group showed significant changes. Both groups reported internal attributions following biofeedback and relaxation training. The high stress group attributed their improvement to the belief they were in control of their minds and bodies, while the low stress group most frequently reported the effort put into the task. The results indicate support for a cognitive explanation for some of biofeedback's effects.

Driving phobia in the city of Houston: a pilot study.

To study the fear of driving phenomenon the authors contacted 48 subjects who, in response to a newspaper article, had expressed an intense fear of driving in the city of Houston and compared them with an age- and sex-matched control group. The information elicited from the subjects suggested the existence of a driving phobia. No significant differences emerged between the phobic subjects and the controls on relevant driving history and background. Although the phobic subjects reported significantly higher levels of anxiety while driving in normal and difficult situations, most of them reported anxiety of phobic intensity only about difficult driving situations, such as driving on freeways and in congested traffic.

Regional cerebral blood flow in depression: a preliminary report.

Regional cerebral blood flow was measured via the Xenon inhalation technique in a group of depressed patients. Marked reductions in regional cerebral blood flow correlated significantly with depth of depression as measured by the Hamilton Depression Scale.

Cerebral blood flow in depression.

This section contains 1) new research findings, including preliminary data from pilot studies, either clinical or laboratory; 2) worthwhile replication studies; 3) case reports that describe a truly new syndrome or cast new light on established ones; and 4) case reports that indicate a new therapeutic procedure of potential value or call attention to adverse effects of drugs or previously unreported complications of therapeutic interventions. Program descriptions and literature reviews cannot be printed in this section. Criteria for format are listed in "Information for Contributors" in each issue; papers that do not adhere to these criteria will be returned to the author.