Impacts of climate change and heat stress on farmworkers’ health: A scoping review

Abstract

Due to the continuous rise in global temperatures and heat waves as a result of climate change, concerns for the health and safety of agricultural workers have increased globally. Agricultural workers are at an increased risk of heat stress due to the strenuous nature of their work which is performed primarily outdoors. Therefore, a scoping review was undertaken to summarize the existing knowledge regarding the impact of climate change particularly extreme heat exposure on farmworkers’ health and the available prevention strategies to alleviate these impacts on farmworkers. A systematic search of 5 electronic databases (Embase, Medline, Scopus, CINAHL and Web of Science) and grey literature websites was conducted to identify relevant literature published until August 24, 2020. Six thousand nine hundred and eight (6908) records were retrieved from the searches and 77 articles were included for the final review. The majority of the reviewed articles focused on (1) heat related illness (HRI), which is a continuum of diseases ranging from mild conditions including heat rash, heat syncope and heat cramps to more severe outcomes heat exhaustion and heat stroke (n=47) as well as kidney disease (n=24). In addition, the majority of the reviewed studies assessing HRI symptoms were conducted in the US, while most studies assessing kidney disease outcomes focused on the Central America region. Risk factors associated with heat-related health outcomes were identified in the reviewed studies, including gender, workload, piece-rate payment, job decision latitude and hot environmental conditions. On the other hand, various protective factors for HRI were identified including reducing soda consumption, taking breaks in the shade, increasing access to regular breaks and changing work hours and activities, while the protective factors for kidney disease included increasing electrolyte consumption. In addition, the most common identified preventive measures include drinking more water, wearing appropriate clothing, taking breaks in shaded areas, going to air-conditioned places during or after work, changing work hours and activities and taking extra breaks. The findings of this review identified several research gaps. Although HRI and kidney disease have been adequately explored in the literature, evidence regarding the effect of heat exposure on other health outcomes such as occupational injuries and mental health was limited in the reviewed studies. Various associations between certain physiological, behavioral and sociodemographic factors (such as acclimatization, hydration, training, migrant status, and poor socioeconomic conditions) and both HRI and kidney disease were understudied in the reviewed literature. The findings of this review also identified a focus on countries in the North and Central America region, while revealing a gap in studies quantifying the burden of heat related health outcomes among agricultural workers in hot regions such as Sub-Saharan Africa, Middle East and North Africa and Southeast Asia, which host millions of vulnerable agricultural workers. Moreover, findings from this review highlighting the high prevalence of HRI among the agricultural workforce coupled with a lack of accessibility to heat preventative measures reflects the need to establish heat safety standards requiring employers to provide heat prevention programs which are suitable to local environmental conditions and physical requirements instead of employee’s self-reliance for prevention and safety. The review has revealed that there is an urgent need to expand future research to cover vulnerable agricultural communities especially in tropical developing countries, including the MENA region, and to investigate the effect of all potential and understudied risk factors and preventive measures so that effective policies and programs can be developed.