Abstract:
Chronic kidney disease of uncertain aetiology (CKDu) is an emerging health concern in
tropical farming communities. The role ofoccupational heat exposure as a potential driver of CKDu
remains debated. Our study examines occupational heat exposure kidney health in three occupational
groups in Sri Lanka.We recruited participants from three occupational groups from three climatic zones;
fisherfolk from the dry and intermediate zones (N=225), paddy farmers from the intermediate zone
(N=180) and tea plantation workers from the wet zone (N=70). Serum creatinine, cystatin-C, urea and
uric acid, estimated glomerular filtration rate and urinary albumin-creatinine ratio were used as
diagnostic criteria of renal impairment.CKDu susceptibility was at the highest among farmers (13.33%), with a significant
differentce compared to the fisherfolk (5.36%; p=0.0003). Among the plantation workers, CKDu
susceptibility was 5.71%, and it was not significantly different compared to the farmers (p=0.087) and
the fisherfolk (p=0.427). Despite higher exposure to heat stress and dehydration, as indicated by the
highest simplified wet bulb globe temperature (sWBGT) in the work environments, fisherfolk
reported the lowest CKDu susceptibility, while farmers and workers with low to moderate heat
exposure showed an increased incidence of abnormal renal function. Further, a multivariable
regression analysis identified a significant effect of occupation (p=0.005), agrochemical exposure
(p=0.001) and age (p=0.001) on the likelihood of CKDu susceptibility while the sWBGT in the
working environments showed no significant effect (p=0.227).With the evidence from our findings, heat exposure alone does not appear to be the
leading driver of CKDu in Sri Lanka, suggesting that the nephropathy is more likely to be associated
with occupational risks such as agrochemical exposures.
