Subclinical signs of renal dysfunction among garage workers

Abstract

The early effects of chronic low level exposure to gasoline vapours and organic solvents on kidney function have been difficult to identify. This study has attempted to identify markers, indicating a risk of kidney dysfunction, which might be useful tools for alerting occupational physicians to the early reversible changes so that preventive measures can be introduced to halt irreversible kidney damage. The exposed group in this study comprised 86 workers occupationally exposed to gasoline vapours and organic solvents in garages; the non‐exposed group was 86 workers not occupationally exposed to the same substances. Exposed workers were matched with non‐exposed by age and nationality. The mean age of the sampled population was 37.4±7.63 years. Current smokers formed 40.7% of the whole population and the percentages among exposed and non‐exposed were broadly similar. Higher percentages of the exposed workers had had their blood pressures measured at a clinic and had had hypertension diagnosed and treated. Of the potential markers of renal dysfunction, we found the relative risk for ketonuria was RR:11.0 (95%, CI: 1.45 ‐ 83.36), for glucosuria RR:1.47 (95%, CI:1.14 ‐ 1.88), for microalbuminuria RR:1.25 (95%, CI:0.94 ‐ 1.67), for leukocyturia RR:1.36 (95%, CI:0.89 ‐ 2.07) and for Cumulative Exposure Index (CEI) RR:2.36 (95%, CI:1.65 ‐ 3.38). Logistic regression modelling showed that ketonuria, microalbuminuria, leukocyturia, proteinuria and CEI were the most significant screening markers after adjusting for other confounding covariates. The logistic regression analysis of the prediction model also showed that CEI (p<0.0001), proteinuria (p=0.01) and glucosuria (p=0.02) were highly significant while ketonuria, microalbuminuria and haemoglobinuria were significant (p=0.05) as markers of kidney damage for the exposed. Thus several of these biological and non‐biological markers had consistently higher scores in the exposed and could prove of value in identifying workers who could be potential targets for manifestation of adverse health effects.