LETTERS POST-MUMPS SCREENING Severe, almost total, generally unilateral, sensorineural deafness is well recognized by the textbooks as a rare complication of mumps. This is the picture as most otologists and infectious disease physicians see it. However, a morbid process which can cause severe effects rarely could be reasonably expected also to cause milder defects more commonly. Further, an illness such as mumps could also be expected to contribute to middle ear catarrh-the parotid is in such close proximity. Therefore, it appeared reasonable to me to include post-mumps screening into the school audiometry program in Redbridge. It is my impression that post-mumps screening provided a higher yield of children with hearing loss than the school population screened routinely at set intervals. I am writing this letter to advocate screening after mumps (and also after measles) of school children. Such a study, besides identifying children with a hearing handicap (to learning), mild or severe, will also be able to confirm or refute may suggestion-that hearing loss after mumps is not rare, not always sensorineural, not always severe, and not generally unilateral. I would welcome contact with others interested in exploring this field further, by organizing large scale studies. J. K. Anand District Community Physician Peterborough Health District
Long Causeway Chambers Long Causeway Peterborough PE1 lYF, Australia
SERUM PARAMETERS IN HARD AND SOFT WATER COMMUNITIES We have read with interest the recent paper by Bierenbaum et al. 84
AJPH JANUARY, 1975, Vol. 65, No. 1
1 -l (Am. J. Public Health 63:169-173, 1973) in which results are presented on biochemical parameters of serum specimens from large groups of healthy residents of cities in the U.S.A., England, and Scotland. The authors conclude that cardiovascular mortality rates are inversely correlated to Ca and Mg concentrations. They also suggest that trace metals may be important in the etiology of coronary heart disease and that intensive investigation is required. Without wishing to dispute these conclusions, there are many puzzling features of the results which seem contrary to expectations. We list these below for each of the six mineral elements investigated.
1. Calcium Bierenbaum et al. give standard deviations (SD) on their four groups as 0.02 to 0.09 mg per 100 ml, which is strikingly less than the usually accepted SD of 0.5 to 0.7.1 Indeed, SD for most Ca methods is greater than the SD for their groups.2 No references are given as to methods used in the determination of Ca, yet it is well known that atomic absorption gives significantly higher values than EDTA titration.3 If the participating laboratories in the U.S.A. and Britain used different methods, then this could explain the observed differences in mean values. This same comment applies equally to the other six elements. Other variables' known to influence serum Ca are concentrations of serum proteins, fasting state, posture, and the use of a tourniquet in collecting blood. The authors fail to mention whether these variables were taken into account. One of us (PGW) has also conducted a survey on serum Ca in London on 1000 healthy subjects. Results were 9.7 ± 0.6 mg per 100 ml compared to 8.57 ± 0.09 mg per 100 ml obtained by Bierenbaum et al. on 150 subjects.
2. Magnesium
Methodological details are not supplied by Bierenbaum et al., but their SD range from 0.01 to 0.03 mg per 100 ml. This is far lower than expected; previous workers give SD about 0.13 mg per 100 ml.4 A recently published studys on serum Mg in London on 75 subjects gives a mean result of 1.94 ± 0.15 mg per 100 ml, compared to their finding of 2.50 + 0.03 mg per 100 ml. We also wish to point out that their London population included many young women, whereas their other groups were mainly men. Oral contraceptives are known to significantly reduce serum Mg6 and could have influenced findings on the London group. This latter effect could also be important for serum Cu and Zn, both of which are influenced significantly by oral contraceptives.7'8
3. Copper Our survey7 of serum Cu concentrations of London women not taking oral contraceptives gave a mean value of 121 ± 15 ,ug per 100 ml, compared to 1.99 + 25 ,ug per 100 ml reported by Bierenbaum et al. However, our groups taking oral contraceptives had mean values of 235 ± 25 gg per 100 ml, so that a "mixed" population could well yield an intermediate result. 4. Zinc
Bierenbaum et al. give SD of 4.6 and 2.7 ,ug per 100 ml for their groups, which are very much lower than the SD of about 15 ,ug per 100 ml reported by others.8'9 Their mean values on the Glasgow group are similar to those seen in women taking oral contraceptives.9 5. Chromium Bierenbaum et al. give 23.1 ± 2.3 and 9.7 ± 0.6 ,ug per 100 ml as their results on their two groups, but the
accepted normal range for human serum is 1.1 to 6.5 ,ug per 100 ml.'0
References
6. Cobalt Bierenbaum et al. give 7.9 ± 0.9 and 5.4 ± 0.7 ,ug per 100 ml, but the accepted normal ranges for human serum are about 0.0007 to 0.025 ,ug per 100 ml.' 0, 1 1 It is well known that there are serious methodological difficulties in the estimation of serum Co. We feel that until some of the difficulties mentioned above have been clarified, interpretation of the findings presented by Bierenbaum et al. is at best difficult.
1. Bold, A. M. Am. Clin. Biochem. 7:131, 1970. 2. Broughton, P. M. G. Am. Clin. Biochem. 6:109, 1969. 3. Eastham, R. D. Biochemical Values in Clinical Medicine, Ed. 4, p. 29. Wright, Bristol, 1971. 4. Archer, W. H., Emerson, R. L., and Reusch, C. S. Clin. Biochem. 5:159, 1972. 5. Herzberg, L., and Bold, A. W. Clin. Chim. Acta 39:229, 1972. 6. De Jorge, F. B., Canato, C., and Medici, E. C. Matern. Inf. 26:261, 1967. 7. Briggs, M. H., Austin, J., and
8.
9. 10. 11.
Staniford, M. Nature 225:81, 1970. Briggs, M. H., Briggs, M., and Austin, J. Nature 232:480, 1971. Halstead, J. A., and Smith, J. C. Lancet 1:322, 1970. Schroeder, H. A., and Nason, A. P. Clin. Chem. 17:461, 1971. Schroeder, H. A., Nason, A. P., and Tipton, I. H. J. Chronic Dis. 19:1007, 1966.
M. H. Briggs, DSc, PhD P. Garcia-Webb, MB FRCPA Biochemistry Department Alfred Hospital Prahran, Victoria 3181 Australia
SIXTH FACULTY INSTITUTE ON MEDICAL CARE SCHEDULED The sixth Faculty Institute on Medical Care, sponsored by the American Public Health Association, will be held June 9-20, 1975, at the University of Michigan, Ann Arbor. The 2-week Institute, designed to expand knowledge of and promote research on medical care organization, will be conducted by nationally known experts on medical care and will offer a series of specialized courses in medical care concepts and issues, health services research, medical economics, international perspectives of health policy issues, politics of health care, and the organization of ambulatory health services. A course on quality assurance will also be included in the curriculum. Registration for the Institute is open to individuals with teaching and research responsibilities in schools of public health, medical schools, programs of hospital administration, and other health professional schools, and to other qualified individuals with significant responsibilities in health program administration. Individuals who have previously attended the course on medical care concepts and issues, or its equivalent, may register for the specialized courses, and may choose three of the six offerings. Tuition fee is $350. Early registration is advised, as enrollment in the program is limited. Applications are available from: Barbara Black, Dept. of Medical Care Organization, M3150, School of Public Health, University of Michigan, Ann Arbor, MI 48104, (313)764-5432.
LETTERS TO THE EDITOR
85
Long Causeway Chambers Long Causeway Peterborough PE1 lYF, Australia
SERUM PARAMETERS IN HARD AND SOFT WATER COMMUNITIES We have read with interest the recent paper by Bierenbaum et al. 84
AJPH JANUARY, 1975, Vol. 65, No. 1
1 -l (Am. J. Public Health 63:169-173, 1973) in which results are presented on biochemical parameters of serum specimens from large groups of healthy residents of cities in the U.S.A., England, and Scotland. The authors conclude that cardiovascular mortality rates are inversely correlated to Ca and Mg concentrations. They also suggest that trace metals may be important in the etiology of coronary heart disease and that intensive investigation is required. Without wishing to dispute these conclusions, there are many puzzling features of the results which seem contrary to expectations. We list these below for each of the six mineral elements investigated.
1. Calcium Bierenbaum et al. give standard deviations (SD) on their four groups as 0.02 to 0.09 mg per 100 ml, which is strikingly less than the usually accepted SD of 0.5 to 0.7.1 Indeed, SD for most Ca methods is greater than the SD for their groups.2 No references are given as to methods used in the determination of Ca, yet it is well known that atomic absorption gives significantly higher values than EDTA titration.3 If the participating laboratories in the U.S.A. and Britain used different methods, then this could explain the observed differences in mean values. This same comment applies equally to the other six elements. Other variables' known to influence serum Ca are concentrations of serum proteins, fasting state, posture, and the use of a tourniquet in collecting blood. The authors fail to mention whether these variables were taken into account. One of us (PGW) has also conducted a survey on serum Ca in London on 1000 healthy subjects. Results were 9.7 ± 0.6 mg per 100 ml compared to 8.57 ± 0.09 mg per 100 ml obtained by Bierenbaum et al. on 150 subjects.
2. Magnesium
Methodological details are not supplied by Bierenbaum et al., but their SD range from 0.01 to 0.03 mg per 100 ml. This is far lower than expected; previous workers give SD about 0.13 mg per 100 ml.4 A recently published studys on serum Mg in London on 75 subjects gives a mean result of 1.94 ± 0.15 mg per 100 ml, compared to their finding of 2.50 + 0.03 mg per 100 ml. We also wish to point out that their London population included many young women, whereas their other groups were mainly men. Oral contraceptives are known to significantly reduce serum Mg6 and could have influenced findings on the London group. This latter effect could also be important for serum Cu and Zn, both of which are influenced significantly by oral contraceptives.7'8
3. Copper Our survey7 of serum Cu concentrations of London women not taking oral contraceptives gave a mean value of 121 ± 15 ,ug per 100 ml, compared to 1.99 + 25 ,ug per 100 ml reported by Bierenbaum et al. However, our groups taking oral contraceptives had mean values of 235 ± 25 gg per 100 ml, so that a "mixed" population could well yield an intermediate result. 4. Zinc
Bierenbaum et al. give SD of 4.6 and 2.7 ,ug per 100 ml for their groups, which are very much lower than the SD of about 15 ,ug per 100 ml reported by others.8'9 Their mean values on the Glasgow group are similar to those seen in women taking oral contraceptives.9 5. Chromium Bierenbaum et al. give 23.1 ± 2.3 and 9.7 ± 0.6 ,ug per 100 ml as their results on their two groups, but the
accepted normal range for human serum is 1.1 to 6.5 ,ug per 100 ml.'0
References
6. Cobalt Bierenbaum et al. give 7.9 ± 0.9 and 5.4 ± 0.7 ,ug per 100 ml, but the accepted normal ranges for human serum are about 0.0007 to 0.025 ,ug per 100 ml.' 0, 1 1 It is well known that there are serious methodological difficulties in the estimation of serum Co. We feel that until some of the difficulties mentioned above have been clarified, interpretation of the findings presented by Bierenbaum et al. is at best difficult.
1. Bold, A. M. Am. Clin. Biochem. 7:131, 1970. 2. Broughton, P. M. G. Am. Clin. Biochem. 6:109, 1969. 3. Eastham, R. D. Biochemical Values in Clinical Medicine, Ed. 4, p. 29. Wright, Bristol, 1971. 4. Archer, W. H., Emerson, R. L., and Reusch, C. S. Clin. Biochem. 5:159, 1972. 5. Herzberg, L., and Bold, A. W. Clin. Chim. Acta 39:229, 1972. 6. De Jorge, F. B., Canato, C., and Medici, E. C. Matern. Inf. 26:261, 1967. 7. Briggs, M. H., Austin, J., and
8.
9. 10. 11.
Staniford, M. Nature 225:81, 1970. Briggs, M. H., Briggs, M., and Austin, J. Nature 232:480, 1971. Halstead, J. A., and Smith, J. C. Lancet 1:322, 1970. Schroeder, H. A., and Nason, A. P. Clin. Chem. 17:461, 1971. Schroeder, H. A., Nason, A. P., and Tipton, I. H. J. Chronic Dis. 19:1007, 1966.
M. H. Briggs, DSc, PhD P. Garcia-Webb, MB FRCPA Biochemistry Department Alfred Hospital Prahran, Victoria 3181 Australia
SIXTH FACULTY INSTITUTE ON MEDICAL CARE SCHEDULED The sixth Faculty Institute on Medical Care, sponsored by the American Public Health Association, will be held June 9-20, 1975, at the University of Michigan, Ann Arbor. The 2-week Institute, designed to expand knowledge of and promote research on medical care organization, will be conducted by nationally known experts on medical care and will offer a series of specialized courses in medical care concepts and issues, health services research, medical economics, international perspectives of health policy issues, politics of health care, and the organization of ambulatory health services. A course on quality assurance will also be included in the curriculum. Registration for the Institute is open to individuals with teaching and research responsibilities in schools of public health, medical schools, programs of hospital administration, and other health professional schools, and to other qualified individuals with significant responsibilities in health program administration. Individuals who have previously attended the course on medical care concepts and issues, or its equivalent, may register for the specialized courses, and may choose three of the six offerings. Tuition fee is $350. Early registration is advised, as enrollment in the program is limited. Applications are available from: Barbara Black, Dept. of Medical Care Organization, M3150, School of Public Health, University of Michigan, Ann Arbor, MI 48104, (313)764-5432.
LETTERS TO THE EDITOR
85
