Enzymatic activity patterns in probability population samples. Serum lactate dehydrogenase.
Sex- and age-specific serum lactate dehydrogenase values provided by a natural population of 2,378 individuals selected by a multistage area cluster probability sampling scheme are given. The activity of this enzyme has definite sex and age associations over the age range studied (larger than or equal to 10 years). In both sexes, it is characterized by elevations in preadolescents, by a sharp decrease in adolescent groups, and by a gradual increase in adult and senescent groups, which, however, does not bring it back to earlier levels. Males have higher mean serum lactate dehydrogenase activities than females in most age groups until about 50 years of age. Unusually high activities have been found in this study, compared with those found in two other widely separated areas in North America using the same assay procedures.