Blinding was not specifically reported, but it was noted that all animals were provided a specific number. It is assumed that the outcome assessors were blind to treatment the same as the academic arm studies. Correspondence with the study authors indicated that the technicians were blind to treatment. (++ for blinding)

Organ weight: weight was collected from animals sacrificed at 1 year, but not at 2 years. It was only noted that organs were weighed. (+ for organ weight method) Overall for methods and blinding = +

Histopathology: Tissues were processed according to NTP specifications (link for methods provided). The International Harmonization of Nomenclature and Diagnostic criteria guidelines was used in the diagnosis of the histopathology (++ for methods). Although it wasn't stated that the slides were evaluated blind, they were reviewed by a Pathology Working Group by a group of external pathologist, which likely minimized the bias (+ for blinding). Overall for methods and blinding =+

Sperm measures: The left epididymis was dissected from the left testis and both were processed for sperm evaluation. The right organ was used if the left had gross lesions. Right organ was used for motility studies. Sperm evaluations were conducted using an integrated visual optic system-automated sperm analyzer. Morphology was evaluated via stained slides with a minimum of 200 cells/animal examined. Details were provided on methods of sperm retrieval. (+ for methods). Overall for methods and blinding =+

NTP 2018

Risk of bias

HAWC