Minimal health impact from exposure to diet-sourced cadmium on a population in central Jamaica

Elevated concentrations of naturally occurring Cd have been found mainly in the bauxitic soils of central Jamaica at levels up to 100-1,000 times higher than typical worldwide averages. Some food crops cultivated on these soils absorb significant amounts of Cd. Autopsy studies of kidney Cd concentrations confirm elevated human exposure, and some long-term residents in central Jamaica exceed the general population average by a factor of two. Diet studies have ascertained that a population in central Jamaica is at risk of being exposed to Cd levels in excess of the Provisional Tolerable Weekly Intake (PTWI) set by the WHO of 7 mu gCd/kg bodyweight/week, and the EU TWI of 2.5 mu gCd/kg bodyweight/week. Elevated levels of urine cadmium (U-Cd) and beta-2 microglobulin (beta 2-MG) concentrations were confirmed with a strong correlation between soil Cd and the U-Cd. Also, higher beta 2-MG concentrations (> 200 mu g/g creatinine) were found in the population with U-Cd concentrations greater than 2.5 mu g/L. While this identification is often taken to indicate impairment in the reabsorption capacity of the renal tubules leading to renal disease, there is no evidence in the mortality records of enhanced deaths in central Jamaica compared with the general population resulting from renal disease or diabetes related complications. The highest median age of death in the island is found in Manchester, the parish with the highest average Cd concentration. While we have identified a possible Cd linked renal dysfunction, significant indications of morbidity are not present in the general population.