PREreview del Use of Urinary β₂-Microglobulin in the Assessment of the Health Risk from Environmental Cadmium Exposure

Write a short summary of the research’s main findings and how this work has moved the field forward.

Major issues

• The study is tilted towards a cross sectional study rather than cohort analysis, because samples were collected just ones, and no longitudinal follow up of the participants. Excerpts from the manuscript supporting this claim are (Data on Cd excretion, β₂M excretion and eGFR were from a Thai cohort of 799 persons. This is also supported by strategies used in the method section where samples of venous blood and morning voided urine were collected after an overnight fasting. 

• In the method section, eGFR was calculated once. This reflects a misclassification as this reading has to last >/= 3months. Also, single spot urine sample introduces high variability because it varies with hydration and diet. Creatine correction also introduces bias because this doesn’t fully reflect the true value of the result.

• Recommendation (The BMD limit (BMDL) value for Cd excretion was 0.17 μg/g creatinine, when eGFR was used as an endpoint. In contrast, the BMDL for Cd excretion could not reliably be estimated, when β₂M was used as an endpoint. Given that a reduced eGFR more reliably indicates the development of chronic kidney disease, we recommend the use of the eGFR to derive a meaningful health protective) doesn’t match the study findings.

Minor issues

• The diagnostic criteria for CKD in the introductory section in my opinions is incorrect because, it should last for 3months and above and not at least 3months.

• I am concerned about the reverse causality mentioned in the introduction not addressed in the study proper.

• Adjustment was only made for age, BMI, gender, smoking and hypertension leaving occupational history, socio-economic status, NSAID use or other metals, which could also serve as confounders.

• Results from figure 1c showed that women had higher BMDL than men but didn’t discuss muscle creatine or its kinetics in the discussion section.

Competing interests

The authors declare that they have no competing interests.

Use of Artificial Intelligence (AI)

The authors declare that they did not use generative AI to come up with new ideas for their review.