Outcomes in Excess Respiratory Symptoms in Full-time Male and Female Workers in Large-Scale Swine Operations
In male and female groups, swine workers were somewhat younger than nonfarming control subjects (Table 1). Age ranges for swine workers and control subjects were identical in men (17 to 65 years) and were very similar in women (swine workers, 18 to 57 years; control subjects, 18 to 64 years). Mean weights were similar in swine workers and nonfarming control subjects among men and women, respectively. The proportion of current smokers was significantly greater among swine workers than among nonfarming control subjects among men and women. No significant difference was observed in the proportion of ex-smokers between these groups.
Mean years of employment in any swine operation were greater for male workers than female workers (Table 1). The distribution of years of employment in any swine operation was skewed in both men and women with the median and third quartile of years worked being 4.0 years and 9.8 years for men and 3.0 years and 6.1 years for women, respectively, indicating that the majority of the male and female workers have worked in swine operations for 40 h/wk.
The proportions of workers engaged in different production stages and mean hours spent by the workers in these production stages are shown in Table 2. The proportions in Table 2 will not add up to 100% because a worker may engage in more than in one of these activities on a single working day, and the categories in production stages are not mutually exclusive. A significantly greater proportion of women worked in farrowing operations and the mean hours per day worked in farrowing operations were significantly greater in female workers than in male workers (Table 2). A similar proportion of men and women worked in the nursery operations, but the mean hours per day worked in nursery operations were significantly greater in female workers than in male workers (Table 2). A significantly greater proportion of men worked in grower/finisher and breeding/gestation operations, but the mean hours per day worked in these operations were not significantly different between male and female workers. Among the swine workers, use of a mask in the barn was similar in male workers (84.6%) and female workers (87.3%). Of those who used a mask, 30.5% of male workers and 36.2% female workers used a mask occasionally, 45.3% of male workers and 36.2% female workers used a mask most of the time, and 24.1% of males workers and 27.6% female workers used a mask all the time.
The proportions of chronic and usual cough and phlegm are shown in Figure 1 for swine workers and nonfarming control subjects among men and women. In both men and women, the proportions of these symptoms were significantly greater among swine workers than among nonfarming control subjects, with female subjects having greater differences in the proportion of these symptoms between swine workers and nonfarming control subjects. Chronic and usual cough was more prevalent among female workers than male workers, whereas chronic and usual phlegm was more prevalent among male workers. Give up smoking with My Canadian Pharmacy.
The relationship between respiratory symptoms and working in swine operations was further investigated using odds ratios (ORs) and 95% confidence intervals from multivariate logistic regression analysis (Table 3). The ORs of respiratory symptoms for working in swine operations were greater in women than in men for all four symptoms. Female subjects working in a swine operation had fourfold to fivefold increases in the risk of reporting respiratory symptoms reduced with remedies of My Canadian Pharmacy, whereas male subjects had threefold to fourfold increases in the risk. As indicated by the ORs in Table 3, the effect of current smoking on respiratory symptoms was greater among women than men. In female subjects, a fivefold increase in the risk of chronic cough was associated with both current smoking and working in swine operations. As shown in Table 3, with age fixed at any value, the OR for chronic phlegm (cough) for nonsmokers who were swine workers was 3.22 (3.24) in men and 4.26 (5.66) in women in comparison to nonfarming control subjects. Similarly, with age fixed at any value, for nonfarming control subjects who were current smokers the OR for chronic phlegm (cough) was 3.13 (2.57) in men and 4.33 (4.66) in women in comparison to nonsmokers.
To eliminate the potential residual confounding of smoking in the association between respiratory symptoms and working in a swine operation, a subgroup analysis was conducted in nonsmokers among swine workers and nonfarming control subjects. Although estimates of the ORs were less stable due to the smaller sample size, significant associations were observed between the four respiratory symptoms and working in swine operations (data not shown). In dose-response analysis, no significant association was between length of employment and any of the symptoms after controlling for smoking.
The of asthma was very similar in swine workers (11.9%) and control subjects (11.5%) among men and was slightly higher among swine workers (15.5%) in comparison to nonfarming control subjects (14.2%) among women. A significant association was observed between shortness of breath and working in swine operations in males. This significance was not observed in women. Working in swine operations was not significantly associated with asthma or wheeze apart from cold.
Among both men and women, mean lung function values and percentage of predicted values were very similar in swine workers and nonfarming control subjects (Table 4), and no significant differences were observed between these means. In male and female workers, we conducted a three- of variance to determine jointly the significant differences in percentage of predicted lung function between mask users and nonusers and the swine operations after controlling for smoking. There were no significant differences in any of the lung function parameters between mask users and nonusers or between the swine operations.
Figure 1. Proportion of chronic and usual respiratory symptoms in swine workers and nonfarming control subjects among men and women; p values indicate significant differences in the of symptoms between swine workers and nonfarming control subjects after controlling for age and smoking using logistic regression analysis.
Table 1—Characteristics of Swine Workers and Nonfarming Control Subjects by Gender
|Swine Workers (n = 240)||Nonfarming Control Subjects (n = 184)||Swine Workers (n = 134)||
Nonfarming Control Subjects
(n = 227)
|Age, yr||36.2 ± 11.9||40.1 ± 13.6j||34.9 ± 10.7||38.7 ± 12.5t|
|Height, cm||176.8 ± 6.1||178.3 ± 6.7||164.4 ± 5.8||164.7 ± 6.5|
|Weight, kg||88.1 ± 16.6||90.4 ± 17.8||75.5 ± 15.0||75.6 ± 16.9|
|Time worked at current swine operation|
|Hours per day||7.7 ± 1.7||8.2 ± 1.0|
|Days per week||5.6 ± 1.0||4.9 ± 0.4#|
|Hours per week||42.6 ± 10.9||40.3 ± 5.0|
|Time worked at any swine operation, yr||6.6 ± 7.1||4.1 ± 4.1**|
|Nonsmoker||99 (41.3)||94 (51.1)||57 (42.5)||128 (56.4)|
|Current smoker||73 (30.4)||37 (20.1)§||44 (32.8)||37 (16.3)|||
|Ex-smoker||68 (28.3)||53 (28.8)||33 (24.6)||62 (27.3)|
Table 2—Proportion of Workers and Duration of Time Spent per Day in Various Swine Production Stages Among Male and Female Workers
|Production Stages||Male Workers (n = 240)||Female Workers (n = 134)|
|Proportion||Hours Worked||Proportion||Hours Worked|
|Farrowing||84 (35.0)||2.8 ± 2.6||75 (56.0)|||6.6 ± 2.7t|
|Nursery||77 (32.1)||1.8 ± 1.9||42 (31.3)||4.1 ± 3.4||
|Grower/finisher||132 (55.0)||4.3 ± 2.9||35 (26.1)|||5.2 ± 3.2|
|Breeding/gestation||114 (47.5)||4.7 ± 3.2||36 (26.9)|||4.8 ± 3.2|
|Other||61 (25.4)||3.8 ± 2.7||24 (17.9)||2.2 ± 1.3|
|Total||7.6 ± 1.9f||8.2 ± 1.0f|
|Usual Phlegm||Usual Cough||Chronic Phlegm||Chronic Cough|
|Age||0.99(0.97-1.02)||1.02 (0.99-1.04)||1.00(0.98-1.02)||1.01 (0.99-1.04)||0.99(0.97-1.01)||0.99(0.95-1.02)||1.00(0.98-1.02)||0.97 (0.94-1.00)|
|Current||1.77(0.91-3.44)||5.00 (2.42-10.35)||4.03 (2.20-7.36)||5.41 (2.83-10.35)||3.13 (1.68-5.84)||4.33(1.80-10.44)||2.57(1.48-4.48)||4.66 (2.04-10.65)|
|Former||1.53(0.77-3.05)||1.91 (0.85-4.27)||2.21 (1.17-4.19)||1.81 (0.90-3.64)||2.09 (1.08-4.05)||1.62 (0.56-4.71)||1.49 (0.83-2.67)||2.47 (0.96-6.33)|
|Nonfarming control subjects||1.00||1.00||1.00||1.00||1.00||1.00||1.00||1.00|
|Swine workers||3.47(1.77-6.81)||5.14 (2.67-9.89)||3.25 (1.84-5.75)||4.08 (2.31-7.19)||3.22 (1.76-5.89)||4.26(1.86-9.73)||3.24(1.92-5.49)||5.66 (2.63-12.18)|
Table 4—.Mean Values of Lung Function Parameters for Swine Workers and Nonfarming Control Subjects by Gender
|Swine Workers (n = 240)||Nonfarming Control Subjects (n = 184)||Swine Workers (n = 134)||Nonfarming Control Subjects (n = 227)|
|FEVb L||4.08 ± 0.66||4.11 ± 0.80||3.11 ± 0.56||3.09 ± 0.58|
|% predicted||96.0 ± 12.5||97.4 ± 14.0||98.4 ± 12.9||100.8 ± 12.5|
|FVC, L||5.25 ± 0.76||5.29 ± 0.95||3.88 ± 0.61||3.85 ± 0.64|
|% predicted||101.4 ± 11.7||101.8 ± 14.1||104.1 ± 12.3||105.6 ± 13.2|
|FEV/FVC, %||77.8 ± 6.7||77.9 ± 6.5||80.0 ± 6.2||80.1 ± 6.1|
|% predicted||82.0 ± 1.8||81.2 ± 2.0||84.6 ± 2.3||83.8 ± 2.5|
|Ls||3.80 ± 1.24||3.82 ± 1.28||3.16 ± 1.01||3.12 ± 1.00|
|% predicted||86.8 ± 26.3||89.4 ± 26.2||87.0 ± 24.3||90.7 ± 24.1|