National and subnational mortality and disability-adjusted life years (DALYs) attributable to 17 occupational risk factors in Iran, 1990-2015

Our plain-English summary of National and subnational mortality and disability-adjusted life years (DALYs) attributable to 17 occupational risk factors in Iran, 1990-2015, by M. Abtahi, A. Koolivand, S. Dobaradaran, et al (Environmental Research, 2018).

The study

• Authors: M. Abtahi, A. Koolivand, S. Dobaradaran, K. Yaghmaeian, S.S. Khaloo, S. Jorfi, S. Keshmiri, A.H. Nafez, R. Saeedi
• Journal: Environmental Research
• Published: 2018;165:158-175
• Cited by: 18 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

We estimated age-sex specific and cause-specific mortality, years of life lost due to premature mortality (YLLs), years lived with disability (YLDs) and disability-adjusted life years (DALYs) attributable to 17 individual occupational risks in Iran at the national and subnational levels in 1990-2015 based on the Global Burden of Disease Study 2015 (GBD 2015). The burden of disease attributable to occupational risk factors was calculated using the comparative risk assessment methodology based on 10 outcomes and 21 risk-outcome pairs. The temporal changes in the attributable burden of disease were decomposed into the contribution of population growth, population ageing, risk-deleted DALY rate, and risk exposure. National DALYs attributable to occupational risks at the national level in 1990, 2005, and 2015 were 138,210 (95% uncertainty interval 64,429-223,028), 193,243 (91,645-310,281), and 228,310 (106,782-371,709), respectively indicating a total increase of 65% (65-67) during the study period. Between 1990 and 2015, the share of the attributable DALYs for women rose by 55% (51-58) from 13% (12-14) to 20% (19-21). The proportion of YLLs in national DALYs attributable to occupational risks during the study period slightly decreased from 24% in 1990 to 23% in 2015. The five occupational risks with the highest contributions in the national attributable DALYs in 2015 were ergonomic factors (107,490), noise (52,122), exposure to particulate matter, gases, and fumes (26,847), asthmagens (19,347), and exposure to asbestos (7842). From 1990 to 2015, the increase in total DALYs attributable to occupational carcinogens (112%) was higher than that for other occupational risks. During the study period, changes in risk deleted DALY rate and risk exposure led to decreases in total DALYs attributable to occupational risks by 14% and 30%, respectively. Based on the Gini coefficient, spatial inequality in DALY rate attributable to occupational risks at the provincial level decreased during 1990-2015. A comprehensive plan for management of exposure to occupational risks, especially occupational carcinogens can cause an important effect for control of the increasing trend of occupational health losses.

Copyright © 2018 Elsevier Inc. All rights reserved.

In plain English

This study estimated deaths and disability-adjusted life years (DALYs, combining years lost to early death and years lived with illness) attributable to 17 occupational risk factors in Iran, 1990 to 2015. The authors applied Global Burden of Disease 2015 methods to Iranian census data. Occupational asbestos exposure was linked to larynx cancer, mesothelioma, ovarian cancer, and tracheal, bronchus, and lung cancer; the article did not name fiber types. Total DALYs attributable to the 17 risks studied rose 65% (95% uncertainty interval 65 to 67), to 228,310 (106,782 to 371,709) in 2015. Asbestos ranked fifth among these risks in 2015, with 7842 DALYs (3632 to 13313), up 102% (98 to 107) from 3887 (1835 to 6434) in 1990. Estimated asbestos-attributable deaths were 252.8 (119.0 to 423.0) in 2015, up from 139.6 (67.6 to 227.5) in 1990. For both sexes combined in 2015, half (0.50) of mesothelioma DALYs were attributed to occupational risks. The authors concluded that managing occupational exposures, especially to carcinogens, could help control rising occupational health losses. They noted their estimates omit some occupational risks and outcomes.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Burden-of-disease modelling study using the comparative risk assessment method of the Global Burden of Disease Study 2015, applied to national and provincial data
• Who was studied: Population of Iran at national and provincial levels, split into urban and rural areas, 1990 to 2015. Exposure was estimated from the economically active population recorded in national censuses (1986 to 2016).
• Exposure: 17 occupational risk factors. Occupational exposure to asbestos (fiber type not specified) was paired with larynx cancer, mesothelioma, ovarian cancer, and tracheal, bronchus, and lung cancer. Exposure was estimated from the distribution of workers across economic activities, not from measurements.
• Main results:
  • National DALYs attributable to the 17 occupational risks studied were 138,210 (95% uncertainty interval 64,429 to 223,028) in 1990 and 228,310 (106,782 to 371,709) in 2015, an increase of 65% (65 to 67)
  • Asbestos was the fifth-largest occupational risk by DALYs in 2015, with 7842 DALYs (3632 to 13313). This was up from 3887 (1835 to 6434) in 1990, a 102% (98 to 107) increase.
  • Estimated deaths attributable to occupational asbestos exposure (both sexes) were 139.6 (67.6 to 227.5) in 1990 and 252.8 (119.0 to 423.0) in 2015, an 81% (76 to 86) increase. Asbestos accounted for 14% of all occupationally attributable deaths in 2015.
  • For both sexes combined in 2015, the population attributable fraction of mesothelioma DALYs for occupational risks was 0.50. For men it was 0.716 in 1990 and 0.656 in 2015. For women it was 0.121 in 1990 and 0.166 in 2015.
  • The summary exposure value for asbestos in men decreased by 5.0% (3.6 to 5.7) from 1990 to 2015
  • For asbestos, the effects of the risk-deleted DALY rate and of risk exposure offset each other. The authors found the increase in asbestos-attributable burden was mainly driven by population growth and ageing. Changes in risk exposure alone accounted for a 35% decrease in asbestos-attributable DALYs.
• The authors' conclusion: The authors concluded that a comprehensive plan for managing exposure to occupational risks, especially occupational carcinogens, could help control the increasing trend of occupational health losses. They placed particular emphasis on women and on provinces with the highest burden.
• Limitations the authors state:
  • Occupational injuries and occupational trichloroethylene exposure were excluded for lack of reliable national and subnational data
  • The estimates do not capture the full occupational burden, because other health outcomes and many other workplace risk factors were not included
  • The study's estimates differ somewhat from those the Global Burden of Disease 2015 study produced for Iran

Related studies

• Diseases attributable to asbestos exposure: years of potential life lost, United States, 1999-2010 — K.M. Bang, J.M. Mazurek, et al. (2014)
• Global and regional burden of disease and injury in 2016 arising from occupational exposures: a systematic analysis for the Global Burden of Disease Study 2016 — GBD 2016 Occupational Risk Factors Collaborators (2020)
• Global, regional, and national burden of non-communicable diseases attributable to occupational asbestos exposure 1990-2019 and prediction to 2035: worsening or improving? — X. Miao, T. Yao, et al. (2024)
• Spatio-seasonal variation, distribution, levels, and risk assessment of airborne asbestos concentration in the most industrial city of Iran: effect of meteorological factors — M. Kermani, A. Jonidi Jafari, et al. (2021)
• Estimating the incidence of lung cancer attributable to occupational exposure in Iran — A. Mosavi-Jarrahi, M. Mohagheghi, et al. (2009)
• Occupational risk factors for mortality from stomach and lung cancer among rubber workers: an analysis using internal controls and refined exposure assessment — K. Straif, L. Chambless, et al. (1999)

Browse more research in Environmental Research, or return to medical research.