7
Alternatively,
our
TREATMENT OF EARLY BREAST CANCER
morbidity measures may be more sen-
sitive than those used in the previous studies. A. R. TURNBULL A. D. B. CHANT R. B. BUCHANAN
Of the laboratory tests studied, blood-lead was the best, and almost exclusive, predictor of morbidity. This has implications for both biological monitoring and for our understanding of how lead causes illness: the criterion of morbidity the most test for routine blood-lead is meaningful prediction, biological monitoring of workers heavily exposed to lead. Unfortunately, it is not the cheapest or easiest test and has the practical disadvantage of requiring blood to be taken. Some of these disadvantages can perhaps be overcome by technical improvements such as the filter-paper-disc method using capillary blood.18 Alternatively, newer tests, such as zinc protoporphyrin, might be good predictors of illness as well as being quicker, cheaper, and more reproducible than blood-lead estimations.19 Whether any tests are better than blood-lead at predicting morbidity in workers less heavily exposed to lead than those we have studied needs investigation. With urinary lead and A.L.A. measurements our results indicate no advantage of correcting for urinary creatinine. 2. How lead causes morbidity.-If the use of spot urine samples for estimation of A.L.A. is a reasonable method of assessing interference with porphyrin metabolism, A.L.A. would be expected to be better than blood-lead in predicting P.c.v. In our study, the correlation between A.L.A. and P.c.v. was 0.45-significantly higher than the correlation between bloodlead and P.c.v. of 0.38 (p
Alternatively,
our
TREATMENT OF EARLY BREAST CANCER
morbidity measures may be more sen-
sitive than those used in the previous studies. A. R. TURNBULL A. D. B. CHANT R. B. BUCHANAN
Of the laboratory tests studied, blood-lead was the best, and almost exclusive, predictor of morbidity. This has implications for both biological monitoring and for our understanding of how lead causes illness: the criterion of morbidity the most test for routine blood-lead is meaningful prediction, biological monitoring of workers heavily exposed to lead. Unfortunately, it is not the cheapest or easiest test and has the practical disadvantage of requiring blood to be taken. Some of these disadvantages can perhaps be overcome by technical improvements such as the filter-paper-disc method using capillary blood.18 Alternatively, newer tests, such as zinc protoporphyrin, might be good predictors of illness as well as being quicker, cheaper, and more reproducible than blood-lead estimations.19 Whether any tests are better than blood-lead at predicting morbidity in workers less heavily exposed to lead than those we have studied needs investigation. With urinary lead and A.L.A. measurements our results indicate no advantage of correcting for urinary creatinine. 2. How lead causes morbidity.-If the use of spot urine samples for estimation of A.L.A. is a reasonable method of assessing interference with porphyrin metabolism, A.L.A. would be expected to be better than blood-lead in predicting P.c.v. In our study, the correlation between A.L.A. and P.c.v. was 0.45-significantly higher than the correlation between bloodlead and P.c.v. of 0.38 (p
