translate English to French: (1993) also performed a nested case-control analysis, for which only a brief account has been published, in which an unspecified number of cases was matched to approximately 50 controls per case, based on survival to the same age.
Les limites inférieures de ces intervalles sont semblables à une estimation antérieure de 200 ppm (200 µg/g) faite par Friberg et al.