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 » Introduction
 » Methodology
 » Results
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  Table of Contents  
ORIGINAL ARTICLE
Year : 2016  |  Volume : 53  |  Issue : 1  |  Page : 44-49
 

Association between occupational history of exposure to tobacco dust and risk of carcinoma cervix: A case-control study


1 Department of Community Medicine, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India
2 Department of Community Medicine, A.J. Institute of Medical Sciences and Research Centre, Mangalore, Karnataka, India
3 Department of Obstetrics and Gynaecology, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India
4 Department of Forensic Medicine, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India
5 Department of Pathology, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India

Date of Web Publication28-Apr-2016

Correspondence Address:
N Joseph
Department of Community Medicine, Kasturba Medical College, Manipal University, Mangalore, Karnataka
India
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Source of Support: Manipal University research grants, Conflict of Interest: None


DOI: 10.4103/0019-509X.180811

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 » Abstract 

Context: Cervical cancer is the second most common malignancy among women in India. There is thus a need to identify unexplored risk factors such as occupational exposure to tobacco dust to justify its increasing trend so as to recommend suitable preventive measures. Aims: The aim was to study the association between occupational exposure to tobacco dust with development of carcinoma cervix. Settings and Design: Case-control study done in two tertiary care hospitals in Mangalore. Methodology: 239 histologically confirmed new cases of cervical cancer and the equivalent number of age-matched controls from 2011 to 2012 were interviewed about occupational history of beedi rolling and related factors. Statistical Analysis: Chi-square test, unpaired t-test, logistic regression. Results: Exposure rate to tobacco dust following beedi rolling was 63 (26.4%) among cases and 38 (15.9%) among controls (P = 0.005, odds ratio [OR] =1.893). The latent period from occupational exposure of tobacco dust subsequent to beedi rolling and development of cervical cancer was found to be 26.5 ± 8.5 years. Adjusted OR of beedi rolling with development of cervical cancer was found to be 1.913 (P = 0.005) after controlling the confounding effect of tobacco usage and was 1.618 (P = 0.225) after controlling the effects of all confounders. Three-quarters of beedi rollers were working in conditions of inadequate ventilation and hardy anybody used face mask during work. About a quarter of participants underwent voluntary screening for cervical cancer. Conclusion: Occupational exposure to tobacco dust was found to be associated with risk of developing cervical cancer. Measures to promote awareness, timely screening of this disease along with the improvement in working conditions is required for improving the health status of beedi rollers and to minimize the incidence of carcinoma cervix in the community.


Keywords: Beedi rollers, carcinoma cervix, case-control study, risk factors, tobacco dust inhalation, tobacco usage


How to cite this article:
Joseph N, Nelliyanil M, Supriya K, Babu Y, Naik R, Purushothama K, Kotian S M, Angeline R, Sharavathi K, Saralaya V, Bhaskaran U, Jain A. Association between occupational history of exposure to tobacco dust and risk of carcinoma cervix: A case-control study. Indian J Cancer 2016;53:44-9

How to cite this URL:
Joseph N, Nelliyanil M, Supriya K, Babu Y, Naik R, Purushothama K, Kotian S M, Angeline R, Sharavathi K, Saralaya V, Bhaskaran U, Jain A. Association between occupational history of exposure to tobacco dust and risk of carcinoma cervix: A case-control study. Indian J Cancer [serial online] 2016 [cited 2017 Aug 17];53:44-9. Available from: http://www.indianjcancer.com/text.asp?2016/53/1/44/180811



 » Introduction Top


Cancer of the cervix is the third most common cancer among women worldwide. In India, it ranks as the second most frequent cancer with the annual number of new cases of 122,844 with a crude incidence rate of 20.2 much higher than 17.1 for South Asia and 15.1/100,000 women/year for the world.[1]

A number of risk factors has been researched and implicated to be associated with this disease. But these alone do not justify its increasing trend. There is a need to identify newer risk factors and adopt suitable preventive measures so as to minimize further cases from occurring.

Over recent times, there has been the focus of tobacco usage as a risk factor for the occurrence of this disease. Tobacco smoking is an established risk factor for carcinoma cervix [2],[3],[4],[5],[6],[7],[8],[9] and so is tobacco chewing.[6],[10] Recent studies have now found passive smoking also as a risk factor for carcinoma cervix.[11],[12],[13] Inhalation of unburnt tobacco dust as a risk factor for carcinoma cervix is an area that has not been so far explored in medicine. Beedi manufacturing which is a century old business in India is one such occupation where such kind of risk is involved.[14] This process involves rolling, roasting, fumigating, and packing. Beedi rollers thus handle tobacco flakes and inhale tobacco dust as well as volatile components of tobacco in their work environment which put them at a high risk of cancer.[15],[16]

Beedi sector is an agroforestry-based second largest industry in India with approximately 4.4 million full-time beedi workers in India with the majority being women mostly from the poor socioeconomic status. The number of beedi workers in Karnataka state of India are officially estimated at about 3.6 lakh of which 2.5 lakh are in Mangalore region alone and of these 80% are home-based workers.[17] Beedi rolling is thus a major occupation for women belonging to the present study settings.

These workers usually stay in small huts which are used for living as well as working spaces. Their work starts from 4 a.m. and extends to 11 p.m., and they work in conditions of inadequate lighting and ventilation in the house which further aggravates the risk of exposure.[17],[18]

From the result of this study, we hope to improve the health status of beedi rollers. This study was hence done to determine the association between occupational exposure to tobacco dust among women beedi rollers along with association of other risk factors in the development of carcinoma cervix.


 » Methodology Top


This case-control study was done in a government and a private tertiary care hospital in Mangalore over a 2-year period from 2011 to 2012. The study was reviewed and approved by the Ethics Committee of the Institute. Cases comprised histologically confirmed incident cases of carcinoma cervix at the respective centers. Sample size was calculated as 236 based on odds ratio (OR) for developing carcinoma cervix of 2.3 among tobacco chewers from a previous Indian study [10] and taking the prevalence of tobacco chewing among Indian women of 11% based on National Family Health Survey-3 survey report [19] and keeping the power of the study at 90%. As per the previous records of these two hospitals, the total number of new cases of carcinoma cervix comes to around 125 cases per/year. Therefore, over 2-year period a total of 239 cases were enrolled. For each case, a 5-year age group matched control from the same hospital admitted with a disease not associated with tobacco usage was enrolled in this study. Controls were ascertained for absence of carcinoma cervix by ruling out symptoms and signs associated with this disease in them. A written informed consent for participation was obtained from each patient.

Carcinoma in situ cases were excluded from the list of cases, and patients with a diagnosis of any cancer or those having tobacco-related diseases (e.g. coronary heart disease or chronic bronchitis) were excluded as controls. The interview schedule was translated into the local language Kannada and was validated and pretested before its use in data collection.

Information on occupation, past medical history, tobacco chewing, smoking, reproductive factors, contraceptive usage and history of screening for cervical cancer was obtained from each participant. Cases and controls were also interviewed about any previous and current history of occupational exposure to tobacco dust.

Socioeconomic status was assessed using Modified B.G Prasad's Classification for 2013. According to this classification, participants with per capita monthly income of Rs. 5113 and above was categorized as Class I, Rs. 2557–5112 as Class II, Rs. 1533–2556 as Class III, Rs. 767–1532 as Class IV and less than Rs. 767 as Class V.[20] Ventilation was considered inadequate if there were <2 windows in each room. Overcrowding within households was assessed by comparison of a number of persons with the number of living rooms and comparing this ratio with standards.[21]

Reproductive span was calculated by subtracting age of menarche from age of naturally attained menopause. Birth spacing of at least 3 years between pregnancies was considered ideal.

Level of personal hygiene was assessed by allotting scores for related questions like history of foul-smelling discharge with associated itching per vaginum before diagnosis of carcinoma, type of pad used and frequency of changing pads during menstrual cycle, habit of cleaning genital parts after micturition or sexual act and frequency of taking bath. With respect to the type of pad used, sanitary pads were given score 1 whereas others like cloth were given score 0. Scores between 0 and 2 were considered poor, 3–4 moderate, and above 5 was considered as good personal hygiene.

Data were entered and analyzed using Statistical package for social sciences (SPSS) for Windows, Version 16.0 Chicago, SPSS Inc. Association was done using the Chi-square test and unpaired t-test. Stepwise forward conditional logistic regression was used to check the association of risk factors under study after controlling the effect of confounders. In those participants with both history of beedi rolling and tobacco chewing, binary logistic regression was used to compute adjusted OR. P ≤ 0.05 was taken as statistically significant association.


 » Results Top


Of the total 239 cases and controls, 175 (73.2%) cases and 176 (73.6%) controls were from private hospital. The mean age of cases was 55.2 ± 11.5 years and controls was 55.3 ± 12.0 years (t = 0.019, P = 0.984).

Among the sociodemographic factors, carcinoma cervix was found to be significantly associated with married women, illiterates, unskilled worker, and women of poor socioeconomic status (Class V) [Table 1].
Table 1: Sociodemographic distribution of study participants

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Exposure rate to tobacco dust following beedi rolling was 63 (26.4%) among cases and 38 (15.9%) among controls (χ2 = 7.846, P = 0.005, OR = 1.893, 95% confidence interval [CI]: 1.207–2.971).

The most commonly manufactured trade name of beedis was Ganesh 46 (45.5%) followed by Bharath 20 (19.8%). Out of the total 101 beedi rollers, only 4 were using face mask to prevent exposure to nicotine dust during work and that too not on a regular basis. Among the 69 workers who roll beedis inside their homes, 52 (75.4%) worked in conditions of inadequate ventilation. Work exposure to tobacco dust while beedi rolling for 3 or more hours in a day (P < 0.001) and >20 years in their lifetime (P = 0.046) was significantly associated with development of carcinoma cervix [Table 2]. Mean hours of beedi rolling per day among cases was 4.2 ± 2.3 while among controls was 3.3 ± 1.6 hours (t = 2.109, P = 0.037). Mean number of beedis rolled per week was 3111.1 ± 1638.1 among cases and 2810.5 ± 1060 among controls (t = 1.01, P = 0.315). The average number of beedis rolled in a week was 2938.6 ± 1271.6 among all workers. Mean years of work experience in beedi rolling was 26.5 ± 8.5 years among cases and 25.1 ± 12.3 years among controls (t = 0.695, P = 0.488).
Table 2: Pattern of beedi rolling among women who were beedi rollers

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The mean latent period from occupational exposure to tobacco dust subsequent to beedi rolling and development of cervical cancer was found to be 26.5 ± 8.5 years.

The mean age at menarche was 14 ± 1.7 years among cases and 13.8 ± 1.6 years among controls (t = 0.943, P = 0.346). Of 371 women who attained menopause naturally, mean age at menopause among cases was 45.8 ± 5.0 years and among controls was 47.4 ± 4.6 years (t = 3.296, P = 0.001). The mean reproductive span was 31.7 ± 5.1 years among cases and 33.6 ± 4.8 years among controls (t = 3.669, P < 0.001). The mean age at marriage was 18.7 ± 3.4 years among cases in comparison to 21.0 ± 5.2 years among controls (t = 5.696, P < 0.001). The mean number of years of married life was 36.5 ± 12.4 years among cases and 34.0 ± 14.3 years among controls (t = 2.032, P = 0.043). The mean number of children was 3.4 ± 1.9 among cases and 2.9 ± 2.0 among controls (t = 2.509, P = 0.012).

Furthermore, the mean age at first pregnancy (includes all gravid mothers irrespective of the outcome of pregnancy) was 20.8 ± 3.4 years among cases and 22.6 ± 5.0 years among controls (t = 4.531, P < 0.001).

Usage of tobacco containing products (P = 0.014) and usage for >10 years (P = 0.047) were significantly associated with the development of cervical cancer. Mean years of tobacco usage among cases was 21.6 ± 12.1 years and among controls was 17.8 ± 14.1 years (t = 1.568, P = 0.12) [Table 3].
Table 3: Association of risk factors with cervical cancer among study participants

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Among beedi rollers, 24 (23.8%) were tobacco users and among non beedi rollers 91 (24.1%) were tobacco users (χ2 = 0.006, P = 0.937).

Sixteen variables entered the stepwise multiple logistic regression model at a significance level ≤0.05. After making adjustments in confounding effects of various risk factors by Binary Logistic Regression method, only usage of oral contraceptive pills (adjusted OR of 10.894), socioeconomic status (adjusted OR of 4.593), and age at menarche (adjusted OR of 0.542) were found to be significantly associated with cervical cancer. However, as the OR of age at menarche was below 1, it was not considered as a risk factor after adjustment. The adjusted OR of Beedi rolling was found to be 1.618 with P = 0.225 [Table 4].
Table 4: Binary logistic regression analysis of risk factors

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After making adjustments in confounding effects of tobacco chewing among participants, the adjusted OR of Beedi rolling in association with development of cervical cancer was found to be 1.913 (95% CI: 1.215–3.01), (P = 0.005).

Of 239 cases, 68 (28.5%) underwent voluntary screening for cervical cancer by Papanicolaou smear. Whereas among controls only 1 underwent voluntary screening. Among the carcinoma cervix cases, the most common associated co-morbidity was hypertension 17 (7.1%) followed by diabetes mellitus 9 (3.8%) and asthma 7 (2.9%).


 » Discussion Top


The present study is the first to report that occupational exposure to tobacco dust while beedi rolling is associated with the development of carcinoma cervix. In another study done in Jabalpur, it was found that inhalation of tobacco dust among beedi rollers resulted in increased DNA damage in peripheral blood lymphocytes compared to controls leading to the increased mutagenic burden.[16] Exposure to tobacco dust similar to what second hand tobacco smoke does, exposes the body to the same carcinogens that are inhaled by smokers. The Hopkins researchers have found that exposure to household passive smoking had a significant association with increased risk for developing cervical neoplasia in a cohort study.[22]

In a meta-analysis involving eleven case-control studies, it was found that women who never smoke but exposed to smoking, experience a 73% increase in risk of cervical cancer compared with non-exposed women (OR = 1.73, 95% CI = 1.35–2.21, P < 0.001).[13] Similarly, in another pooled analysis of seven case-control studies from five countries found an increased risk of invasive cervical cancer for nonsmoking women with partners who smoked (OR = 1.34; 95% CI: 0.91–1.96).[11]

In the present study, only four beedi rollers were using face mask. In a study done in Andhra Pradesh, it was found that knowledge and practice regarding personal protective measures were quite poor as 87% of workers were not using any protective measures during beedi rolling.[23] In another study done in Mumbai, none of the beedi rollers were wearing masks or gloves and none were aware of these safety measures. Furthermore, none were aware of benefits provided for them under various laws.[24]

Studies done in Andhra Pradesh [23] and Mumbai [24] reported that 79% and 75% beedi workers were working in poor housing conditions with inadequate ventilation which was similar to our observations.

About a quarter of beedi rollers in this study were sitting in groups and working, which further increases the quantity of tobacco dust inhaled. It has been suggested that the workers have to sit in the direction facing the direction of the wind to avoid inhalation of blown away tobacco dust.[16]

Overcrowded living conditions were also reported by about 32% beedi rollers in this study putting other family members also at risk of health hazards of tobacco dust. As per the Beedi and Cigar Workers (Conditions of Employment) Act 1966, proper lighting, ventilation and avoidance of overcrowding at workplace needs to be ensured by the factories for women who are employees of manufacturers even though they are doing the job at home.[25]

In this study, three women were found to be beedi rolling for >9 hours a day. In a study done in Mumbai, it was observed that women work on an average for 8 h a day. Five women (9.62%) used to work for 10–12 h a day.[24]

Regulation of working hours mentions that no employee is required to work >9 h a day or 48 h in a week. There are therefore a number of issues that need to be addressed in the beedi sector in India. Even after 40 years of implementation of the act, there is no significant improvement in the beedi workers' working conditions both in factories and at home.[25]

Hardly, one-quarter of the patients in the present study underwent screening for carcinoma cervix voluntarily. This may be due to lack of awareness of occupational risk of cancer as observed among 81% participants in the study done in Andhra Pradesh [23] and 92.3% in the study done in Mumbai.[24]

This emphasizes the importance of periodic screening among high-risk women. Considering the expenditure involved and the lack of cytology manpower, screening at 5 and 10 years intervals appears to be a remote possibility in developing countries like India. Hence, single lifetime screening appears to be a feasible approach as a strategy for control of cervical cancer. According to WHO Recommendations (1986), screening at 45 years of age is the most correct approach, which could detect approximately 20% of the total cervical cancer cases.[26]

Other studies have reported that 67.3%[24] and 91%[23] beedi rollers were not seeking medical care in spite of being sick. Reason could be because they constitute a major share of the workforce below the poverty line who earn as low as Rs. 23 for rolling 1000 beedis a day.[15] The Beedi Workers Welfare Fund (BWWF) Act, 1976 was enacted to provide for welfare schemes for the beedi workers and their families, relating to health, education, maternity benefits, group insurance, recreation, housing assistance etc.[17]

The number and location of hospitals and dispensaries set up under the BWWF need to be improved relatively to the geographic spread of the beedi workforce in South Canara district. The per capita expenditure incurred on medical care and screening activities out of the welfare fund also needs to be raised to meet the standards of medical care. There is therefore a need to tie up health services under the BWWF with the primary health care centers of the state governments to broaden access of services.[17]


 » Conclusion Top


Occupational exposure to tobacco dust following beedi rolling, work exposure of 3 or more hours a day and work experience of >20 years in this profession were significantly associated with development of carcinoma cervix along with other known risk factors.

Three-fourth of the indoor beedi rollers were working in conditions of inadequate ventilation and hardly 4 workers used face mask during work.

Awareness generation about health hazards associated with occupational exposure, usage of face mask during work, improvement of indoor ventilation and periodic screening for early identification of carcinoma cervix is required among women beedi rollers. They should also be made aware of the welfare schemes provided to them by the government. The health care workers and anganwadi workers in the urban slums and rural areas can play a key role in these initiatives during their periodic home visits. Strategies to control the other identified risk factors of carcinoma cervix should also be taken simultaneously to contain the increasing incidence of carcinoma cervix in Indian population.

Limitations

This being a hospital-based study, inherent limitations of selection bias may be possible. Cases and control may not represent a particular geographic area. Recall bias is also likely to have occurred while interviewing each of the subjects.

Even though this was a funded project, the authors had the ability to complete the research as planned and they had full control of all primary data.


 » Acknowledgments Top


We authors thank Manipal University, Manipal for the research grants provided to meet the expenditure of this study.

 
 » References Top

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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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