New study conducted in Sweden shows that low-level cadmium exposure is associated with decreased bone thickness and can lead to osteoporosis

Regulation (EU) 2019/1009 will fully apply from 16th July 2022, introducing, among others measures, a mandatory limit of 60 mg of cadmium per Kg of inorganic and organo-mineral fertilizers.

It is an important milestone for the case of promoting sustainable agriculture in Europe because for the first time such a limit has been fixed at EU level, as a result of an arduous compromise-building process among the co-legislators.

Meanwhile, scientific research continues to be published highlighting how dangerous even low-level cadmium exposure can be for human health.

According to a recent Swedish study¹, cadmium that enters the human body, even at low levels, can be associated with reduced bone thickness and bone volume fraction, which may explain the increased risk of fractures and osteoporosis.

Cadmium is a wide-spread pollutant in many parts of the world. This heavy metal occurs in air, water and soil both naturally and as a result of the use of cadmium-containing fertilizers and pollution from industrial activities, and is absorbed by growing crops. In the general population, the main sources of cadmium are diet and cigarette smoking. Cadmium is present in most food items, but agricultural crops such as wheat and potatoes usually account for the majority of human dietary cadmium intake. In humans, cadmium isabsorbed in the gut and accumulates mainly in the kidney.

It is well known that exposure to high levels of cadmium can cause osteoporosis, osteomalacia and can increase the risk of fractures. However, recent studies conducted in Sweden, Belgium and the United States have also shown associations between low-level cadmium exposure and increased risk of osteoporosis and fractures.

The mechanisms behind cadmium’s effect on bone are still not fully clear, but it has been suggested that there are both indirect and direct effects.

A possible indirect mechanism is decreased formation of active vitamin D in the kidney, resulting in decreased calcium uptake from the intestine, while suggested direct effects mainly focus on the stimulation of osteoclast formation and/or activity, resulting in increased bone resorption.

The study conducted in Sweden aimed at understanding if cadmium exposure in the general Swedish population can cause other bone changes on top of decreased areal bone mineral density (e.g. changes in microstructure and geometry, such as cortical thickness or area, cortical porosity and trabecular bone volume²).

The study appears to show significant negative associations were found between U–Cd (cadmium in urine) and several bone geometry or microstructure parameters, with 9% lower cortical thickness, 7% lower cortical area and 5% lower trabecular bone volume fraction. 

The results indicate that low-level Cd exposure in the general population has negative effects on both cortical and trabecular bone.