We examined the association between renal function and As methylation capacity.
Blood and urine As metabolites and eGFR were analyzed in 375 As-exposed adults.
eGFR was significantly associated with increased %InAs and decreased %DMA in urine.
The relationship between %InAs in blood vs. in urine was weaker in low eGFR strata.
Urinary excretion of InAs may be impaired in those with reduced eGFR.