An interventional study of rice for reducing cadmium exposure in a Chinese industrial town

Abstract

Background: Reducing cadmium (Cd) exposure in Cd-polluted areas in Asia is urgently needed given the toxic effects of Cd. The short-term and long-term benefits of lowering Cd exposure are unknown because of its long half-life in the body. Objectives: We aimed to investigate whether an intervention with low-Cd rice in a contaminated area of China reduced urinary Cd (UCd) levels and improved blood pressure and kidney function outcomes compared to no-intervention in consumers of high-Cd rice in the same region. Methods: 106 non-smoking subjects were divided into three treatment groups: the intervention group (replacing homegrown high-Cd rice with market low-Cd rice, n=34), the non-intervention group (continue eating high-Cd rice, n=36) and the control group (continued eating low-Cd rice they have been eating for years, n=36). The intervention period lasted for almost 8 months, during which participants were visited on up to 4 occasions and UCd, systolic and diastolic blood pressure (SBP, DBP), kidney function biomarkers (β2-microglobulin and N-Sacetyl-β-D-glucosaminidase) were measured. Results: After 3 months, the geometric mean UCd in the intervention (Int) group decreased significantly by 0.32 μg/g (p=0.007), while changes were not significant in the non-intervention (non-Int) group (0.13 μg/g, p=0.95) or the control group (−0.01 μg/g, p=0.52). UCd in the Int group remained lower than in the non-Int group but higher than in the Control group through the end of follow up. DBP in the Int group decreased significantly from 80 mm Hg at month three (p= 0.03) and stayed around 74 mm Hg for the remainder of the study. SBP also decreased in the Int group but with variations similar to those observed in the other two groups. The two kidney biomarkers showed variations without a clear pattern. Conclusion: This study suggested that UCd reflected both short-term (< 3 months) and long-term Cd exposure. In addition, the low-Cd rice intervention showed initial benefits in lowering blood pressure levels, especially DBP, but not kidney biomarkers.

An updated systematic review on the association between Cd exposure, blood pressure and hypertension

“…Urine Cd levels were associated with increase in both blood pressure and hypertension in one study ( Wang and Wei, 2018 ). Associations were found between urine Cd levels and increased diastolic blood pressure ( Gao et al, 2018 ; Huang et al, 2019 ), and with pregnancy-induced hypertension ( Liu et al, 2018 ). In an adolescent sample, no significant association was found between urine Cd levels and systolic blood pressure ( Castiello et al, 2020 ).…”

“…The same relationship between urinary Cd levels and hypertension ( Van Larebeke et al, 2015 ) and with pregnancy-induced hypertension ( Liu et al, 2018 ), was found in both cross-sectional studies. A longitudinal decrease in urine Cd was documented upon decreased exposure to environmental sources with a significant decrease in DBP ( Huang et al, 2019 ). No association between urinary Cd levels and high blood pressure was found in one large and cross-sectional study ( Shiue and Hristova, 2014 ).…”

Cadmium contamination in agricultural soils of China and the impact on food safety

“…High Cd home-grown rice should be exchanged with low-Cd rice from the local authorities. A recent study has shown that a 3-month intervention by supplying low-Cd rice to farmers who previously consumed home-grown rice can significantly decrease urinary Cd (Huang et al, 2019).…”

Adverse Impact of Heavy Metals on Bone Cells and Bone Metabolism Dependently and Independently through Anemia

“…[5] For example, as typical heavy metals, Cd and Pb can damage the kidney, liver and lung, and induce anemia, nephrotoxicity, heart failure, and diabetes. [6][7][8] Heavy metals can induce detrimental effects on humans through various mechanisms, such as oxidative stress, [9,10] even exerting synergistic effects with other pollutants. [11] Furthermore, mounting evidence revealed through epidemiological, in vivo, and in vitro studies that heavy metals can induce disordered bone homeostasis and are involved in the development of degenerative bone diseases, including osteoporosis (OP), osteoarthritis (OA), degenerative disk disease (DDD), and osteomalacia, particularly OP ( Figure 1).…”