Occupational health outcomes among sanitation workers: A systematic review and meta-analysis

• Type of Material: Article
• Authors: Hemali Harish Oza, Emory University; Madison Gabriella Lee, Emory University; Sophie Boisson, World Health Organization; Frank Pega, World Health Organization; Kate Medlicott, World Health Organization; Thomas Clasen, Emory University
• Language: English
• Date: 2022-03-01
• Publisher: ELSEVIER GMBH
• Publication Version: Final Published Version
• Copyright Statement: © 2021 The Authors
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.ijheh.2021.113907
• Title of Journal or Parent Work: INTERNATIONAL JOURNAL OF HYGIENE AND ENVIRONMENTAL HEALTH
• Volume: 240
• Start Page: 113907
• End Page: 113907
• Grant/Funding Information: Hemali Oza was supported in part by a grant from the National Institute of Environmental Health Sciences, USA (5T32ES12870-17); Frank Pega was funded by staff salary from the World Health Organization.; This work was supported by a grant from the World Health Organization (Grant No. WSH/PHE 2019/974207).
• Keywords: Systematic review; WASTE-WATER; Public, Environmental & Occupational Health; TREATMENT PLANTS; SYMPTOMS; Occupational exposures; SEWAGE WORKERS; Life Sciences & Biomedicine; ENDOTOXIN EXPOSURE; HELICOBACTER-PYLORI; RISK-FACTORS; PULMONARY-FUNCTION; HEPATITIS-A; Infectious Diseases; Occupational health; A VIRUS-INFECTION; Science & Technology; Sanitation workers
• Research Categories: Environmental Sciences; Health Sciences, Public Health

Abstract

Background: Sanitation workers are essential to global public health and societal wellbeing. However, the health risks and outcomes associated with exposure to occupational risk factors among sanitation workers are neither well understood nor well quantified. We undertook a systematic review to (1) identify occupational risk factors among sanitation workers and (2) assess the effect of occupational exposure to human fecal sludge and wastewater on selected health outcomes among these workers. Methods: We searched four databases (i.e., PubMED, MEDLINE, EMBASE, and LILACS) for eligible studies from inception through to January 01, 2020. The included population was workers ≥15 years engaged, formally or informally, in installing, operating, servicing, cleaning or emptying a sanitation technology at any step of the sanitation chain. The included comparator was workers in other occupations or the general population. Eligible outcomes were: mortality (any or all causes), gastroenteritis, occupational injuries, respiratory diseases, musculoskeletal disorders, and mental and social health conditions. Risk of bias was assessed separately on exposure assessment and health outcome using a modified Liverpool Quality Assessment Tool (LQAT). We pooled sufficiently homogenous studies using inverse variance meta-analysis with random effects. Results: A total of 65 studies (9 cohort studies, 56 cross-sectional studies) met the inclusion criteria. One quarter of studies (n = 15) were from middle-income countries. Few studies assessed occupational risk factor exposures directly; most assigned exposure via proxy of occupation of sanitation worker. We judged nearly all studies to have “high risk of bias” in exposure and outcome assessment. Despite these limitations, the consistency of the overall evidence suggests that sanitation workers are at increased risk of gastroenteritis and respiratory conditions, and may be at increased risk of musculoskeletal disorders and mental/social health conditions. The pooled odds ratio for hepatitis A–the only outcome deemed suitable for meta-analysis–was 2.09 (95% Predicted Interval: 1.39–3.00, 12 studies). There was conflicting evidence from studies of increased risk of mortality; only one study reported on injuries. Conclusion: Despite a large number of studies, there is limited evidence to date of the health risks faced by sanitation workers, particularly among groups that may be at particular risk– women, informal workers and those living in low-income countries. Nevertheless, the research to date provides suggestive evidence of elevated occupational risk among sanitation workers across a range of health condition. More research is needed to improve the current bodies of evidence for all included health outcomes to be able to quantify disease burden among this occupational group.