Hydration Status and Kidney Health of Factory Workers Exposed to Heat Stress: A Pilot Feasibility Study

Abstract

Dehydration associated with heat stress increases the risk of workplace injury or illness, decreases productivity, and may contribute to the chronic kidney disease epidemic identified in outdoor workers from hot climates. There is limited research on the effects of chronic occupational heat stress among indoor workers. We aimed to test the feasibility of measuring markers of hydration and kidney function in foundry factory workers in Southern Brazil, exposed and not exposed to heat stress. Factory workers exposed to heat stress (wet bulb globe temperature ≥28.9) and not exposed to heat were identified by management and invited to participate. Clinical and biochemical markers of hydration and kidney function were evaluated before and after a single 8.5 h work shift (lunch time not included). Feasibility outcomes included rates of enrolment, % completion of study protocols, and time to complete data collection. This study was deemed feasible with 80% enrolment and 90% completion of the protocol. Among the preselected workers, the enrolment rate was 91%. All subjects completed the physiological measures and blood collection and 95% completed the urine studies. Mean time to complete data collection pre-shift was 19.1 ± 4.2 min and post-shift: 14.3 ± 4.0 min. Workers exposed to heat stress had a greater decline in estimated glomerular filtration rate compared to controls over the work shift (–13 ± 11 vs. –5 ± 7 mL/min; p < 0.01). We demonstrated the feasibility and challenges of conducting future hydration and kidney function research among indoor factory workers. Further study is needed to determine if exposure to indoor heat contributes to a decline in kidney function.

Relationship of heat stress with acute kidney disease and chronic kidney disease: A literature review

“…Decreased kidney function can be experienced by workers suffering from heat stress or conditions that can cause heat stress such as poor rehydration. 6,10,11 Heat stress, exposure to heat for more than 6 h, heavy workload, inadequate rehydration, and lack of proper rest periods can also cause acute kidney disease. [12][13][14][15][16][17][18][19][20][21] If this condition is experienced by workers continuously, heat stress can also increase the risk of chronic kidney disease.…”

Heat Safety in the Workplace: Modified Delphi Consensus to Establish Strategies and Resources to Protect the US Workers

“…More recently, the impact of hypohydration on aspects of worker health beyond the workplace has begun to be elucidated. For instance, repeated exposure to a hypohydrated state caused by severe physical work in the heat has been proposed to bring about chronic kidney disease, which is speculated to be due to the workers experiencing repeated bouts of subclinical kidney injury (Glaser et al., 2016 ; Hansson et al., 2020 ; Johnson et al., 2019 ; Mix et al., 2018 ; Nerbass et al., 2017 , 2019 ; X. Yang et al., 2020 ). Cases of chronic kidney disease have been reported in workers performing manual work in hot environments in hottest regions in the world (Aguilar & Madero, 2019 ; Butler‐Dawson et al., 2019 ; Glaser et al., 2016 ; X. Yang et al., 2020 ).…”

Impact of Heat Stress on Renal Function: A Systematic Literature Review Focusing on Workplace Heat

“…Construction workers also risk developing kidney damage, as indicated in previous studies [20][21][22]. On the contrary, in some studies, no statistically significant difference has been observed between workers with and without HS in kidney function biomarkers [23][24][25]. Controversy can be observed between studies investigating the effect of HS on kidney function.…”