Physiological and psychosocial occupational exposures and intermediate health outcomes in
the general population
Faruque, Md Omar
DOI:
10.33612/diss.154938193
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Publication date: 2021
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Faruque, M. O. (2021). Physiological and psychosocial occupational exposures and intermediate health outcomes in the general population. University of Groningen. https://doi.org/10.33612/diss.154938193
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Chapter 1
GENERAL INTRODUCTION
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GENERAL INTRODUCTION
According to the Oxford English Dictionary work is “an action or activity involving physical or mental effort and undertaken in order to achieve a result, especially as a means of making one's living or earning money” (1). In modern society, work is a key element to materialize well-being, to participate in society, and to fulfill important psychosocial needs (2). In addition, work plays a central role in providing individual identity, social roles, and social status (3,4). However, all the positive fundamental influence of work on the individual and society set aside, some aspects of work can be hazardous and may pose risks to workers’ health (2). The health hazards posed by occupational exposures were already recognized by Hippocrates who recommended physicians to consider patients’ occupational background in diagnosing and treating disease (5). In the 17th century, Bernardino Ramazzini further emphasized the idea of Hippocrates and wrote the first systematic description of occupational diseases and their causes (6). To protect worker health, occupational epidemiology emerged as a branch of epidemiology in the 19th century and became a quantitative science in the 20th century. Occupational epidemiology investigates conditions in the workplace that are associated with health outcomes among workers (6-8). The ultimate goal of occupational epidemiology is to protect workers from these harmful occupational exposures (both physical and non-physical) by identifying them and, subsequently, controlling, reducing, or removing them by applying appropriate preventive measures.
In 2014, in the European Union, 4.3% of the population had a doctor-diagnosed chronic lower respiratory disease that included chronic bronchitis, emphysema, and other chronic obstructive pulmonary diseases (COPD) (9). In that year, in the Netherlands, the prevalence of chronic lower respiratory disease was approximately 5% (9). Although tobacco smoking is the primary preventable risk factor for respiratory diseases (10), other factors, such as occupational exposures, may also be considered as risk factors for respiratory diseases. Sickness absence (absence from work due to illness) also poses a substantial burden to society. In 2019, in the Dutch working population, workers were absent for an average of 4.4% of their working days due to illness (11). Between 2007-2011, in the Netherlands, an average of 1.6 and 10.9 days of sickness absence was attributable to respiratory and cardiovascular diseases (CVD) which costs are €109 million and €458 million per year (12).
To reduce the health risks posed by occupational exposures, it is important to identify these occupational exposures (risk factors) and to apply preventive
General introduction
11
measures accordingly. It is further important to identify occupational risk factors associated with sickness absence.
Occupational exposures, either physiological, e.g. dust, gases/fumes, and pesticides, or psychosocial, e.g. job strain and effort-reward imbalance, are experienced by the workers at the workplace and may have adverse effects on health among the workers. Potential hazardous factors at the workplace are exposures (e.g. dusts, mists, gases, fumes, vapours, aerosols, and fibers), biological factors (e.g. bacteria, viruses, or fungi), chemical factors (e.g. pesticides and solvents), physical factors (e.g. noise, ionizing radiation, and heat), ergonomic factors (e.g. increased repetition, excessive vibration, or repetitive motion), and psychosocial factors (e.g. high psychological job demands, low job control, violence or lack of recognition).
Previous studies have found strong associations between occupational exposures (physiological or psychosocial) and COPD (13,14) and CVDs (15). Chronic diseases are of long duration and slow progression (16). These diseases cannot be prevented by vaccines or cured by medication, and stay for lifelong (17). Therefore, studying early markers or early stages of disease, i.e. intermediate health outcomes, is important to be able to intervene in an early stage of (chronic) disease development.
Intermediate health outcomes (18) may be viewed as proxy or marker of chronic disease development and could provide valuable information about the potential health risk of occupational exposures at an early stage. Examples of intermediate health outcomes are reduced lung function for COPD, elevated blood pressure for CVD, and elevated blood inflammatory biomarkers for inflammatory diseases. So far, little is known about the associations between occupational exposures (physiological and psychosocial) and intermediate health outcomes. Identification of occupational exposures associated with intermediate health outcomes will enable us to develop early preventive measures, and subsequently, reduce the prevalence of chronic diseases by targeted primary interventions.
Therefore, in this thesis, to our knowledge, we are the first to investigate the associations between physiological (e.g. airborne exposures) and psychosocial (e.g. job strain) occupational exposures, measured by a job-exposure matrix (JEM), and intermediate health outcomes (lung function, blood pressure, and inflammatory biomarkers) in a large general working population.
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Measurement of occupational exposures
In this thesis, JEMs were used to estimate both physiological and psychosocial occupational exposures. The best way to estimate individual physiological occupational exposure is by quantitative measures of hazardous agents either externally (e.g. concentrations in the air or on the skin) or internally (e.g. concentrations in the body tissues or excreta). However, in a large general population, it is often difficult to obtain these exposure data around or in individual persons as such quantitative measures require substantial effort and costs in large scale general population studies. Thus, proxy measures, such as JEMs, are commonly used to estimate occupational exposures (19,20).
A general population-based JEM links workers' self-reported job titles to the occupational exposures, assessed by experts (Figure 1). A population-based JEM allows to link the same exposures to different jobs. This type of JEM uses job coding systems (e.g. International Standard Classification of Occupations, ISCO) to incorporate a wide range of occupations that might be seen in the general population. Several general population-based JEMs have been developed based on expert opinion supported by published literature and communication with industry specialists (21-23).
Figure 1: A part of the ALOHA+ JEM (24,25). ISCO= International Standard Classification of Occupations. 0 = no exposure, 1 = low exposure, and 2 = high exposure.
In this thesis, occupational exposures were estimated using JEMs. In chapters 2, 3, and 5, the ALOHA+ JEM was used. The ALOHA+ JEM links job titles (based on ISCO-88 (26)) to estimated exposures, i.e., biological dust, mineral dust, gases/fumes, insecticides, herbicides, fungicides, aromatic solvents, chlorinated
General introduction
13
solvents, other solvents, and metals. In chapter 4, the Asthma-specific JEM (21) was used to estimate 30 occupational exposures (e.g. flour, latex, acrylates, wood, and organic solvents). In chapter 6, job strain, effort-reward imbalance, and emotional demands were estimated as psychosocial occupational exposures using recently developed psychosocial JEMs (27,28).
Data source—Lifelines Cohort Study
All studies in this thesis are conducted within the sampling frame of the Lifelines Cohort Study (29). The Lifelines Cohort Study, a large observational population-based cohort study, started in 2006 and aims to disentangle the role of genetic factors, lifestyle, and the environment in the development of chronic diseases and healthy aging. Inhabitants of the three northern provinces (Friesland, Groningen, and Drenthe) of the Netherlands were invited to participate in the study. In the Lifelines Cohort Study, three generations of participants were recruited: the index person (aged 25-50 years), their partners, parents (in-law), and children. The recruitment stopped in December 2013 after including 167,729 subjects (age range: 6 months - 93 years). The first follow-up visit was performed after a median of 4.5 years (range:1.8-8.8 years). The job titles of the Lifelines Cohort Study subjects were linked to the ALOHA+ JEM, the Asthma-specific JEM, and the psychosocial work factor JEMs.
The Lifelines Cohort Study contains a large amount of quality data which allows us to adjust for important confounders. The large study population further allows us to examine the effect of occupational exposures on objectively measured intermediate health outcomes across different susceptible groups, for example, males and females. Our study population is predominantly Caucasian as the immigration rate is very low in the Northern part of the Netherlands. Since the study population belongs to similar geographical locations, our study findings are not confounded by air pollution. Next to the homogeneity of the cohort in terms of ethnicity and geographical location, we expect that people in the same job will perform their tasks in a more or less similar manner due to cultural work habits and this will lead to homogeneity of exposure within subjects with the same job. This contrasts with studies in which subjects from different countries are included as cultural work habits will differ between countries and this will lead to a larger variability in exposure between subjects with the same job.
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Aim of the thesis
To investigate the associations between physiological and psychosocial occupational exposures and intermediate health outcomes in a large general working population. The specific research questions addressed are:
Research question 1: Are occupational exposures associated with sickness absence? Are the associations mediated by respiratory symptoms and moderated by genetic make-up?
Research question 2: Are occupational exposures associated with lung function? Are the associations moderated by sex and smoking?
General introduction
15
Research question 3: Are occupational exposures associated with inflammatory biomarkers?
Research question 4: Are occupational exposures associated with the risk of developing respiratory symptoms and airway obstruction?
Research question 5: Are psychosocial work factors associated with blood pressure? Are the associations moderated by sex?
Outline of the thesis
In chapter 1, an overall introduction of the thesis is provided. Information regarding
physiological and psychosocial occupational exposures, JEMs, and how different types of occupational exposures were estimated using JEMs were described. In addition, the rationale for using intermediate health outcomes is provided. Data sources, measures, and aims and specific research questions are presented. In chapter 2, we investigated the associations between occupational exposures
(assessed with the ALOHA+ JEM) and self-reported sickness absence in the Lifelines Cohort Study. Furthermore, we examined whether the associations were mediated by respiratory symptoms and modified by genetic make-up. ‘Any sickness absence’ was defined as being absent from work due to illness or problems (except pregnancy) at least one day in the last year (yes/no). ‘Long-term sickness absence’ was defined as being absent from work due to illness or problems (except pregnancy) for two consecutive weeks or more in the last year (yes/no).
In chapter 3, we examined the associations between occupational exposures
(assessed with the ALOHA+ JEM) and baseline lung function level and annual lung function decline in the Lifelines Cohort Study. We also investigated whether the associations were modified by sex and smoking. Four lung function parameters were analyzed: Forced Expiratory Volume in One Second (FEV1), Forced Vital Capacity (FVC), Forced Expiratory Flow over the middle half of the FVC (FEF25-75), and FEV1/FVC.
In chapter 4, we investigated the associations between occupational exposures
(assessed with the Asthma-specific JEM) and levels and changes of inflammatory biomarkers (eosinophil, neutrophil, and C-reactive protein) in the Lifelines Cohort Study.
In chapter 5, we examined the associations between occupational exposures
16
(chronic cough, chronic phlegm, and chronic bronchitis) and airway obstruction in the Lifelines Cohort Study. We further investigated whether the associations were modified by age, sex, and smoking. Chronic cough was defined as “Usual coughing first thing in the morning, or during the day, or at night in winter for at least three months in a year.” Chronic phlegm was defined as “Usual bringing up any phlegm first thing in the morning, or during the day, or at night in winter for at least three months in a year. Chronic bronchitis was defined as the presence of both chronic cough and chronic phlegm. Airway obstruction was defined as FEV1/FVC below the lower limit of normal.
In chapter 6, we investigated the associations between psychosocial work factors
(job strain, effort-reward imbalance, and emotional demands), assessed with three separate JEMs, and blood pressure in the Lifelines Cohort Study. In addition, we examined whether the associations were modified by sex. Hypertension was defined as SBP ≥140 mm Hg or DBP ≥90 mm Hg or self-reported use of antihypertensive medication.
In Chapter 7, a summary of all study findings is given. In the discussion section,
the theoretical and methodological considerations are discussed. The implications for research, practice and policy as well as future perspectives and recommendations are presented.
General introduction
17
REFERENCES
1. "work, n." OED Online. 3rd ed. Oxford University Press, 2020, Available from:
www.oed.com/view/Entry/230216.
2. Waddell G, Burton AK. Is work good for your health and well-being? London: TSO (The Stationery Office), 2006.
3. Marks N, Shah H. A well-being manifesto for a flourishing society. J Public Ment Health 2004;3(4):9.
4. Nordenmark M, Strandh M. Towards a sociological understanding of mental well-being among the unemployed: The role of economic and psychosocial factors. Sociology;33(3):577–97. 5. Rom WN. The discipline of environmental and occupational medicine. 4th ed. Philadelphia:
Wolters Kluwer/Lippincott Williams & Wilkins, 2015.
6. Checkoway H, Pearce N, Kriebel D. Research Methods in Occupational Epidemiology. 2nd ed.
New York: Oxford University Press, 2004.
7 Kriebel D, Checkoway H, Pearce N, Kriebel D. Exposure and dose modelling in occupational epidemiology. Occup Env Med 2007;64:492–8.
8. Hernberg S. Introduction to Occupational Epidemiology. Chelsea, MI: Lewis, 1992. 9. Respiratory diseases statistics. Deaths from diseases of the respiratory system. Available
from:
https://ec.europa.eu/eurostat/statisticsexplained/index.php/Respiratory_diseases_statistics#De aths_from_diseases_of_the_respiratory_system
10. Chronic obstructive pulmonary disease (COPD). Available from: http://www.who.int/news-room/fact-sheets/detail/chronic-obstructive-pulmonary-disease-(copd)
11 de Best R. Sickness absence rate in the Netherlands 2001-2019. Available from: https://www.statista.com/statistics/543963/sickness-absence-rate-in-the-netherlands/
12. de Vroome EM, Uegaki K, van der Ploeg CP, Treutlein DB, Steenbeek R, de Weerd M, van den Bossche SN. Burden of sickness absence due to chronic disease in the Dutch workforce from 2007 to 2011. J Occup Rehabil 2015;25(4):675-84.
13. de Jong K, Marike Boezen H, Kromhout H, Vermeulen R, Vonk JM, Postma DS, et al. Occupational Exposure to Vapors, Gases, Dusts, and Fumes Is Associated with Small Airways Obstruction. Am J Respir Crit Care Med 2014;189(4):487–90.
14. de Jong K, Boezen HM, Kromhout H, Vermeulen R, Postma DS, Vonk JM, et al. Pesticides and other occupational exposures are associated with airway obstruction: the LifeLines cohort study. Occup Environ Med 2014;71(2):88–96.
15. Diène E, Fouquet A, Esquirol Y. Cardiovascular diseases and psychosocial factors at work. Arch Cardiovasc Dis 2012;105(1):33-9.
16. Bernell S, Howard SW. Use your words carefully: what is a chronic disease?. Front Public Health 2016;4:159.
17. Siel W.C. Medical Definition of Chronic disease. Available from: https://www.medicinenet.com/script/main/art.asp?articlekey=33490
18 Goldman D, Ducci F. Deconstruction of vulnerability to complex diseases: enhanced effect sizes and power of intermediate phenotypes. Sci World J 2007;7:124-30.
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19. Peters S. Although a valuable method in occupational epidemiology, job-exposure matrices are no magic fix. Scand J Work Environ Health 2020;46(3).
20. Fadel M, Evanoff BA, Andersen JH, d'Errico A, Dale AM, Leclerc A, Descatha A. Not just a research method: If used with caution, can job-exposure matrices be a useful tool in the practice of occupational medicine and public health? Scand J Work Environ Health 2020;46(5):552-553.
21. Le Moual N, Zock JP, Dumas O, Lytras T, Andersson E, Lillienberg L, Schlünssen V, Benke G, Kromhout H. Update of an occupational asthma-specific job exposure matrix to assess exposure to 30 specific agents. Occup Environ Med 2018;75(7):507-14.
22. Gomez MR, Cocco P, Dosemeci M, Stewart PA. Occupational exposure to chlorinated aliphatic hydrocarbons: Job exposure matrix. Am J Ind Med 1994;26(2):171–83.
23. Plato N, Steineck G. Methodology and utility of a job-exposure matrix. Am J Ind Med 1993;23(3):491–502.
24. Sunyer J, Kogevinas M, Kromhout H, Antó JM, Roca J, Tobías A, Vermeulen R, Payo F, Maldonado JA, Martinez-Moratalla J, Muniozguren N. Pulmonary ventilatory defects and occupational exposures in a population-based study in Spain. Am J Respir Crit Care Med 1998;157(2):512-7.
25. Sunyer J, Zock JP, Kromhout H, Garcia-Esteban R, Radon K, Jarvis D, Toren K, Künzli N, Norbäck D, d'Errico A, Urrutia I. Lung function decline, chronic bronchitis, and occupational exposures in young adults. Am J Respir Crit Care Med 2005;172(9):1139-45.
26. International Labour Office. International standard classification of occupations: Geneva: International Labour Organization. ISCO-88 (1990).
27. Framke E, Sørensen JK, Andersen PK, Svane-Petersen AC, Alexanderson K, Bonde JP, Farrants K, Flachs EM, Hanson LL, Nyberg ST, Villadsen E. Contribution of income and job strain to the association between education and cardiovascular disease in 1.6 million Danish employees. European heart journal 2020;41(11):1164-78.
28. Rugulies R, Framke E, Sørensen JK, Svane-Petersen AC, Alexanderson K, Bonde JP, et al. Persistent and changing job strain and risk of coronary heart disease. A population-based cohort study of 1.6 million employees in Denmark. Scand J Work Environ Health 2020;46(5):498-507.
29. Scholtens S, Smidt N, Swertz MA, Bakker SJ, Dotinga A, Vonk JM, et al. Cohort Profile: LifeLines, a three-generation cohort study and biobank. Int J Epidemiol 2015;44(4):1172–80.
