Abstract

Respiratory problem is one of the main occupational health challenges faced by farmworkers, it can occur while preparing and applying pesticides and during tasks in recently sprayed fields. Symptoms associated with different respiratory problems include coughing, wheezing and airway inflammation are commonly observed among farmworkers who are occupationally exposed to pesticides. In low and middle-income countries, epidemiological evidence for the association between occupational exposure to pesticides and respiratory diseases in adults is limited. The study employed a cross-sectional survey that ran from January to February 2021 using face to face semi-structured questionnaire administered to farmworkers who were working on flower and coffee farms in Arusha and Kilimanjaro. Approximately 384 farmworkers were randomly selected to participate in this study. The study included organic and non-organic farmworkers who were directly engaged in agricultural activities and exclude supporting staff such as human resource managers who were not engaged directly in agricultural activities. The results indicate that non-organic farmers were at high risk of developing respiratory symptoms than organic farmworkers. Non-organic farmers were significantly associated with cough, rhinitis, and shortness of breath among farmworkers [adj. OR (95% CI) 31.94 (12.04, 84.70), 4.44 (2.61, 7.56) and 6.44 (1.98, 20.95)] respectively. However, there should be a systematic collection of data about poisoning cases occurring in the farm areas with a large number of employees so that effective measures can be taken to protect the farmers from chronic illnesses associated with pesticide exposure, particularly respiratory problems in this case.

1. Introduction

Pesticides are consumed annually worldwide in controlling pests and pest-induced diseases to increase productivity in agriculture settings ¹. Pesticides such as herbicides, insecticides, fungicides, bactericides, and rodenticides are widely used in controlling pests ². Occupational pesticide exposure is one of the main occupational health hazards facing farm workers worldwide ^{3, 4}. Pesticides entering the body through inhalation may result in major problems in the respiratory system ². Exposure to these pesticides occurs during the production, transportation, preparation, and application of pesticides in the agricultural setting ^{2, 5}. A person using these chemicals needs to wear personal protective equipment (PPE) as recommended by the United Nations Environmental Protection Agency ⁶. According to ⁷, about 300 million people are reported to suffer and die from chronic respiratory diseases such as asthma and 210 million people suffer from the chronic obstructive pulmonary disease (COPD). In Tanzania epidemiological evidence on the association between occupational exposure to pesticides and respiratory diseases among farmworkers is limited. Therefore, this study aimed at addressing the relationship between pesticide exposure and the occurrence of respiratory symptoms among farmworkers in Tanzania. The study findings may enable decision-makers and responsible ministries to make informed decisions for better management and control of exposure to pesticides for improved health and economic development of individual farmworkers and the nation at large.

2. Materials and Methods

The current study was conducted in Arusha and Kilimanjaro regions (Figure 1). It focused on purposively selected estates for coffee and flowers plantation. In the Arusha region, the study was conducted in Arumeru District, involving Burka estate, Selian coffee estate, and Derkker bruin flower farm (in Arusha and Kilimanjaro) while in the Kilimanjaro region the study was conducted at Moshi Rural District in Machari coffee estates and Bondeni flower farms. These regions were selected because of the availability of large-scale farmers on flower and coffee farms.

This was a cross-sectional study whereby farmworkers from flower and coffee plantations were asked to participate. In this study, coffee farms included two farms where farmers were applying pesticides (non-organic) and one farm that served as an organic farm because farmers were not applying pesticides. On the other hand, all selected flower farms used pesticides and therefore denoted as nonorganic farms. Despite the desire to include control farms, it was not viable since none of the flower farms in the study area were farming without the use of pesticides.

In this study, occupational exposure to pesticides, respiratory symptoms, demographic and confounding factors were collected through a structured questionnaire. Moreover, confounding factors were identified as determinants of outcomes of interest. Farmers engaged in the organic farm were considered as a control group (non-exposed group) while those engaged in non-organic farming were considered as an exposed group. Both male and female farmworkers aged between 18 and 48 years and working in flower and coffee plantations in Arusha and Kilimanjaro region.

The sample size for respondents was calculated based on the proportions of the total number of farmworkers employed on each selected farm: Burka coffee estate (n=350), Selian Coffee Estate (n=246), Machari Coffee Estate (n= 1451), Dekker bruins in Arusha (n=238), Dekker bruins in Moshi (n=476) and Bondeni flower (n= 134). This resulted in a study population of 2895 farmworkers.

The following formula was used to obtain the total sample size for the study (Daniel, 1999)

Where,

Zα/22 is the critical value of the Normal distribution at α/2 (e.g. for a confidence level of 95%, α is 0.05 and the critical value is 1.96), MOE is the margin of error, p is the sample proportion, N is the population size =2895 farmers and n = 384 respondents

We also considered a non-response rate of 1% = 385*0.01=3.85=4 respondents

Hence resulted in a total sample size of 389 respondents.

In the quantitative research design, we used simple random sampling whereby a stratified sampling was used to get the number of participants in each farm as shown in Table 1.

For qualitative sampling, a purposive sampling technique was used to identify study participants from the sampling population of 389. Therefore, twenty-four participants of which twelve were working on the non-organic farm and the other twelve were working on an organic farm. These participants were selected based on their experience regarding pesticide exposure and the development of respiratory symptoms in the occupational setting.

Farmworkers (pesticide sprayers, storekeepers, mixers, pickers and pruners) directly engaged in farming activities from flower and coffee plantations were included in the study. Farm administrators and other supporting staff such as human resources who are not engaged in agricultural activities were excluded.

Detailed questionnaires on socio-demographic aspects, lifestyle factors and respiratory health were included. The socio-demographic and lifestyle factors included sex, age, education, marital status, parental history of respiratory problems, cigarette smoking (past and current smokers), sharing room with smokers, use of cleaning detergent, a vegetable garden at home and treatment of domestic pesticides for the past three (3) months. These variables were defined as confounding variables to be used in the analysis of the association between occupational exposure to pesticides and the prevalence of respiratory symptoms among our study participants.

In this study, cough, rhinitis, wheeze, shortness of breath and cough with phlegm were considered respiratory symptoms if they persisted for over three (3) months. These symptoms were included in this study because they were reported in previous studies ^{8, 9, 10}.

A questionnaire is base on categories such as types of farming (non-organic farming vs. organic farming), large farming system and working area (greenhouse vs. open field), occupational status (sprayers and mixer vs. organic farmers flower pickers), mix and spray pesticides (yes vs. no), washing spray instrument after pesticides application (yes vs. no), taking bath after work (yes vs. no), wearing protective gear (yes vs. no) and washing hands after work (yes vs. no) was administered to farmworkers directly engaged in farming activities. Farmers who used pesticides were considered the exposed group while those who did not use pesticides were considered the non-exposed (control group).

Data were analysed using statistical software namely Stata version 15 and NVivo version 12 for qualitative analysis specifically content and thematic analysis (analysis of major themes and contents). The descriptive analysis of quantitative data included the use of descriptive statistics, measures of frequency and counts with diagrams. Inferential statistics was employed by using a model in assessing the influence of factors on exposures to occupational risks. The Binary logistic regression was used to assess the association of the outcomes of interest with occupational exposure to pesticides from non-organic farms in coffee and flowers, which were defined as the types of farming, large farming system and working area, occupational status, mix and spray pesticides, washing spray instrument after pesticides application, taking bath after work, wearing protective gear and washing hands after work.

The analyses were performed with and without adjustment for the potential confounding factors described above and the impact of the potential confounders. The association estimates were assessed by comparing the adjusted and unadjusted estimates. The associations are presented as odds ratios (ORs) with 95 percent confidence intervals (CIs); Wald tests were used to determine the statistical significance of the relationships among the categorical exposure variables.

The data were also analysed qualitatively to determine the study participant’s awareness of the effects associated with occupational exposure to pesticides and increased risk of respiratory symptoms. In this aspect, we used the following questions; when do you experience respiratory problems? And how do farmers protect themselves during farming activities?

Ethical approval for this study was obtained from the Research and Publication Committee of Sokoine University of Agriculture, Tanzania. Informed consent was obtained from the participants before the commencement of the interview.

3. Results

Participants in the exposed group and control group were 194 exposed and 195 non exposed, which is equivalent to 49.9 percent and 50.1 percent respectively. Most of the participants had Primary education while only few had Secondary Education. Based on age, most farm workers in this study had the age between 38-48.

About 41% (n=80) were non-organic coffee and 100% (n = 195) were organic farmers in coffee. The occupational status of the study participants based on the pesticide exposure was as follows: 26% (n=30) were flower pickers and 50 % (n = 57) were sprayers and mixers in non-organic flowers, 5% (n=4) and 25% (n=29) of the study participants in non-organic coffee and non-organic flowers were pesticides mixer and sprayers. 61% (n= 69) and 23% (n = 18) of study participants in non-organic flower and non-organic coffee respectively washed spray instruments after pesticide application. Moreover, 23 % (n =18) and 36% (n=41) of the study participants in non-organic coffee farms and non-organic flower farms take a bath after work. (Table 2 and Table 3).

There was a statistical association between smoking cigarettes (P = 0.002), current smoker (P = 0.000), sharing a room with a smoker (P=0.037) and domestic pesticide treatment (P = 0.026), use of cleaning detergent at home (0.009) and having a vegetable garden at home (P 0.000) and the farm type (exposed and non-exposed) (Table 4).

Results showed a statistical association between respiratory symptoms and type of farm. All respiratory symptoms had a P value of less than 0.05 (Table 5).

Results showed that neither practicing non-organic coffee nor non-organic flower has no significant association with the respiratory symptoms as all p-values were >0.05 (Table 6).

The results showed a statistical association between type of farming (non-organic coffee) and increased risk of cough [adj. OR (95% CI) 76.65 (15.36,382.37), Rhinitis 3.90 (2.04,7.46) and 10.97 (1.76,68.21). In non-organic flowers, there was a statistical association between non-organic flower farming and increased risk of cough 77.25 (20.36,293.13) and Rhinitis 6.66 (3.30,13.45) but there was no statistical association between non-organic flower farming and shortness of breath 3.08 (0.04,256.79) (Table 7 and Table 8).

Pruners and Pickers

In non-organic farming (coffee) there was a statistical association between pruning of coffee and increased risk of cough 76.65 (15.36), rhinitis 3.90 (2.04, 7.46) and shortness in breath 10.97 (1.76.68.21) and also in non-organic flowers, there was a statistical association between the picking of flowers and increased risk of cough 148.29 (30.62, 718.04), rhinitis 7.79 (2.87, 21.14). However, there was no statistical association with the increased risk of wheezing 0.70 (0.14,3.50) and cough with phlegm 0.63 (0.16,2.42).

Mix and Sprayers of Pesticides

There was a statistical association in non-organic coffee between mixing and spray of pesticides and increased risk of cough 20.85 (1.91,227.68), wheeze 309.98 (14.27,6735.34) and cough with phlegm 22.57 (2.16,235.41). In-organic flowers, there was also a statistical association with increased risk of cough 4.58 (1.68, 12.54) and rhinitis 4.74 (1.83.12.29). However, no statistical association was observed in non-organic flowers with shortness of breath at 9.38 (0.07, 1196.29) and cough with phlegm at 3.49 (0.81, 15.09).

Taking Bath after Work

There was a statistical reduction in risk for cough 0.19(0.071, 0.50) and 0.31 (0.17, 0.56) when the participants take shower after work on the coffee farm. However, no statistical reduction in risk for shortness of breath 0.38(0.10, 1.48) and cough with phlegm 0.32(0.06, 1.70) when the study participant take shower after work on the coffee farm. In non-organic flowers, there was a statistical reduction in the risk of cough 0.33 (0.16, 0.68) and rhinitis 0.44 (0.26, 0.75) when the study participants take shower after work. However, no statistical significance was observed for wheeze 0.37(0.10, 1.43), shortness of breath at 12.85 (0.39, 422.13), and 0.44(0.14, 1.45) when the participants take shower after work.

Wearing protective gear

There was no statistical risk reduction for cough 0.57 (0.23, 1.45), rhinitis 0.58 (0.30, 1.11) and shortness of breath 0.37 (0.06, 2.31) when the study participants wear protective gear in non-organic coffee farm. We observed no statistical risk reduction for cough 2.01 (0.98, 4.12), Rhinitis 1.45 (0.83, 2.55), wheeze 0.76 (0.193, 2.96), shortness of breath 0.40 (0.01, 10.86) and 0.30 (0.80, 1.09) for participants wearing personal protective equipment in non-organic flower.

Washing Hand after Work

We observed a statistical association between participants washing hands after work on the coffee farm with increased risk of cough 5.27(1.07, 25.99), wheeze 1.06 (0.26, 4.39), shortness of breath 0.38 (0.10, 1.48) and cough with phlegm 0.32 (0.61, 1.70) in non-organic farms. However, no association was observed between participants washing hands and increased risk of cough 2.09 (0.22, 19.47) in non-organic farms. In non-organic flowers, the results indicate no statistical association between washing hands after work and increased risk of cough 1.18 (0.39,3.52) and rhinitis 0.70 (0.31,1.58).

The findings of qualitative data indicated that the risk of developing respiratory symptoms among farmworkers in the greenhouses (exposed group) depends on the extent of pesticide exposure and the nature of the work such as picking, mixing, grading, and spraying. According to farmworkers, pickers get respiratory symptoms during either entering or going to the nearby greenhouse. Furthermore, sprayers and mixers are reported to get this problem the first time of exposure to pesticides but with time they adapt to this condition; thus, ending up getting respiratory symptoms including rhinitis especially when they use foliar to treat plants.

Information on the proper wearing of safety gear and handling of pesticides during pesticide application showed that sprayers wear safety gears appropriately and thus seemed less exposed to pesticides and therefore had less risk of getting respiratory symptoms as compared to the control group. Farm workers in greenhouses lacked ventilation facilities that allow free movement of air as a result; too much sweating seems to elicit skin irritations.

4. Discussion

This study revealed the association between occupational exposure to pesticides and respiratory symptoms including cough, cough with phlegm, rhinitis, wheeze, and shortness of breath among farmworkers aged between 18 and 45 years in coffee and flower plantations.

Occupational exposure to pesticides is correlated with various respiratory pathologies such as chronic obstructive pulmonary diseases and various respiratory manifestations of cough, wheezing, rhinitis, shortness of breath and dyspnea as previously described ^{6, 11}. The study conducted by ¹² reports the increase of the risk in the health problems including respiratory symptoms among the farmworkers who applied pesticides. In this study behavioral characteristics such smoked cigarette, current smoker, sharing room with a smoker, use of cleaning detergent at home, vegetable garden at home and the use of pesticides at home were considered as factors which may also exacerbate respiratory symptoms among farmworkers. Self-behaviors such as smoking among farmworkers, have been reported with previous studies to be the source of respiratory health problems ¹³.

The number of women employed as farmworkers was higher compared to men, also female farmworkers were at greater risk for adverse health outcomes including respiratory problems than male farmworkers, the same outcome also reported by ¹⁴.

The uses of PPE were depending on the nature of work, in this study only men farmworkers employed as pesticides mixers and sprayers were using PPE while women farmworkers including flower pruners and coffee pickers were not using PPE due to several causes including uncomfortableness’, inconvenience and excessive heat. ¹⁵ this indicate women were at great risk of pesticides exposure than men. This finding is similar to a study conducted among the Latina farmworkers which found that the pesticide exposure to be twice as high in women as in men ¹⁶.

Farm workers employed as pruners in flower and pickers in non-organic coffee had an increases risk of cough, rhinitis and shortness of breath. In this study we noticed that flower pruners went into the greenhouse without wearing of person protective equipment’s few hours after spray of the pesticides, further it was observed that most of the greenhouses did not have enough ventilation. These findings are similar to a study conducted in Ethiopia which was investigating if the occupational exposure to pesticides was associated with respiratory health effect in commercial farming system ¹¹.

Despite of wearing of person protective equipment’s, it was found that pesticides mixers and sprayers were at increased risk of developing respiratory symptoms. This finding is in agreement with a study by ¹⁷ on self-reported symptoms and Pesticide Use among Farm Workers.

In this study results showed that neither practicing non-organic coffee nor non-organic flower has no significant association with the respiratory symptoms as all p-values were >0.05 all the adjusted behavior characteristics such as smoking of cigarette were associated with increased risk of developing respiratory symptoms, hence neither working in organic farm nor in non-organic farm the exposures risk was considered to be the same. The other findings have been relatively nonspecific both in term of the agent causing the respiratory symptoms ¹⁸. Also in this case, it is difficult to conclude that a farmworker had a respiratory symptoms resulted from exposure to pesticides if a farmer smoke, use cleaning detergents at their homes or sharing bedroom with smoker.

In this study, it was noticed that participants who took showers after work had decreased risk of cough and rhinitis in the coffee and flower plantations. Moreover, study participants who wear protective gear had lower risk of cough, rhinitis and shortness of breath though the difference was statistically insignificant (P > 0.05). These findings were in line with the findings in studies conducted in Turkey which suggest the reduction of respiratory symptoms for participants wearing personal protective equipment among farmworkers ^{18, 19, 20, 21}. In this study, it was noticed that participants who took showers after work had decreased risk of cough and rhinitis. ¹⁹, revealed the increase of respiratory symptoms among farmworkers took bath after work. The time interval of showering after pesticides application also can rise or decrease the respiratory symptoms depend on the type of pesticides used ²². Moreover, in this study the participants who wear protective gear had lower risk of cough, rhinitis and shortness of breath though the difference was statistically insignificant (P > 0.05). Other studies also have been reported the decrease of respiratory symptoms among the farmworkers in the use of personal protective gears ^{18, 19, 20, 21}.

In the view of published literature, it was suggested that pesticide management and regulations, educational programs on safety precautions and reinforcement of safety behaviours, especially the proper use of personal protection gears in the workplace are effective measures of preventing respiratory symptoms and diseases related to occupational exposures to pesticides ¹⁸.

5. Conclusions

In this study organic farming was defined as a chemical-free agriculture practices which avoid the use of synthetic inputs, and relying on natural substances which are typically originated from animal or plants. While non organic farming involve the use of synthetic substances which are manufactured by chemicals and industrial processes and may include products not found in nature or simulation of products from natural sources, hence the farmworkers in organic farmers were not exposed to the chemicals while non organic farmworkers were exposed to chemicals.

In this study it was observed that the prevalence of respiratory symptoms was higher among farmworkers in non-organic farming than in organic farming. This study strongly recommend for adherence to OSHA guidelines on occupational safety in relation to pesticides uses. To implement these guidelines, employers should provide regular on-the-job training to their employees

Employers should have a close follow-up on employees’ complaints regarding respiratory symptoms, as most of the symptoms were found to be associated with other diseases such as malaria. A close follow-up will prevent farmers from chronic respiratory symptoms.

Acknowledgements

I would like to express my deep gratitude to all who have in one way or another assisted me to accomplish this work through their assistance and professional advice. Again, I am indebted to my Supervisors Prof. Robinson H. Mdegela and Dr. Frida Mgonja who were constantly reviewing the write up and giving constructive way forward. Their valuable time, comments, technical guides, suggestions and criticism contributed much to the outcome of this work. Also special thanks should go direct to all staff members of Tanzania Plant Health and Pesticide Authority (TPHPA) and Managing Directors of all farm visited for their valuable cooperation

Consent for Publication

All the authors consented for the publication of this manuscript.

Availability of Data and Materials

The datasets used for this study are available from the corresponding author upon reasonable request

Funding

This study was self-funded.

Authors Contribution

This work was prepared in close cooperation with my Supervisors from proposal, fieldwork, data analysis and preparation of the manuscript for publication.

Conflict of Interest Statement

The authors declare that they have no conflict of interest.

References