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- gO - Letters to the Editor Letters are welcomed and will be published, iffound suitable, as space permits. The editors reserve the right to edit and abridge letters, to publish replies, and to solicit responses from authors and others. Letters should be submitted in duplicate, double-spaced (including references), and generally should not exceed 400 words.
AJPH Welcomes Significant Laboratory Studies In July 1978, the Executive Board of the American Public Health Association unanimously decided to discontinue publication of Health Laboratory Science. The reason for this decision was failure of the journal to attain financial self-sufficiency. Health Laboratory Science was created a number of years ago to provide for the publication of papers primarily emanating from the Laboratory Section of APHA. Since July, concern on the part of Laboratory Section members has been expressed and these conversations culminated in a meeting between Dr. Alfred Yankauer, Editor of the American Journal of Public Health, and Dr. Frank Lambert, Dr. Martin S. Favero, and Mr. Paul Bonin, immediate past, current, and ChairpersonElect, respectively, at the Annual Meeting of the APHA in Los Angeles during the week of October 15, 1978. Dr. Yankauer informed these Labora-
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tory Section officers that good quality laboratory-oriented manuscripts of significance to public health would be welcomed in the American Journal of Public Health and would be editorially reviewed in the same manner as other manuscripts submitted to the Journal. It was agreed that the Laboratory Section would recommend a number of individuals who could act as reviewers for these types of manuscripts. Martin S. Favero, PhD Chairperson, Laboratory Section American Public Health Association
On Correlation between SIDS Rates and General Infant Mortality Rates In the article by Blok' which considers the geographic variation in the incidence of sudden infant death syndrome (SIDS) in North Carolina, there is a methodological error. One concern in the study is the relationship between SIDS rate and the total infant mortality rate. He (correctly) notes that since SIDS cases represent approximately 10 per cent of total infant mortality, some positive correlation between the two measures would be expected. More precisely, one would expect a correlation of approximately 0.32 since 10 per cent of the variance in the general in-
fant mortality is attributable to SIDS cases and the proportion of shared variance is r2 (r2 = 0.10, r = 0.32). Thus, under the null hypothesis that SIDS incidence rate is independent of the rate of all other (non-SIDS) causes of infant mortality, r = 0.32 should serve as the null hypothesis rather than the null hypothesis tested by Blok that r = 0. Another more direct means of overcoming this difficulty would be to calculate the rate of "non-SIDS infant mortality" for each city and county and then determine the correlation with SIDS rates. When Blok states that "the existence of a higher than average general infant mortality rate may likely be taken as an indication that a higher than average SIDS rate is also present" (p. 372), he is, in effect, elaborately restating the fact that 10 per cent of infant mortality is due to SIDS. What is of interest to this reader (ahd presumably to Blok as well) is whether or not the rate of SIDS correlates with other causes of infant mortality.
David A. Savitz Department of Preventive Medicine Ohio State University Columbus, OH43210 REFERENCE 1. Blok JH: The incidence of sudden infant
death syndrome in North Carolina's cities and counties: 1972-1974. Am J Public Health 68:367-372, 1978.
AJPH January 1979, Vol. 69, No. 1
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0
- gO - Letters to the Editor Letters are welcomed and will be published, iffound suitable, as space permits. The editors reserve the right to edit and abridge letters, to publish replies, and to solicit responses from authors and others. Letters should be submitted in duplicate, double-spaced (including references), and generally should not exceed 400 words.
AJPH Welcomes Significant Laboratory Studies In July 1978, the Executive Board of the American Public Health Association unanimously decided to discontinue publication of Health Laboratory Science. The reason for this decision was failure of the journal to attain financial self-sufficiency. Health Laboratory Science was created a number of years ago to provide for the publication of papers primarily emanating from the Laboratory Section of APHA. Since July, concern on the part of Laboratory Section members has been expressed and these conversations culminated in a meeting between Dr. Alfred Yankauer, Editor of the American Journal of Public Health, and Dr. Frank Lambert, Dr. Martin S. Favero, and Mr. Paul Bonin, immediate past, current, and ChairpersonElect, respectively, at the Annual Meeting of the APHA in Los Angeles during the week of October 15, 1978. Dr. Yankauer informed these Labora-
82
tory Section officers that good quality laboratory-oriented manuscripts of significance to public health would be welcomed in the American Journal of Public Health and would be editorially reviewed in the same manner as other manuscripts submitted to the Journal. It was agreed that the Laboratory Section would recommend a number of individuals who could act as reviewers for these types of manuscripts. Martin S. Favero, PhD Chairperson, Laboratory Section American Public Health Association
On Correlation between SIDS Rates and General Infant Mortality Rates In the article by Blok' which considers the geographic variation in the incidence of sudden infant death syndrome (SIDS) in North Carolina, there is a methodological error. One concern in the study is the relationship between SIDS rate and the total infant mortality rate. He (correctly) notes that since SIDS cases represent approximately 10 per cent of total infant mortality, some positive correlation between the two measures would be expected. More precisely, one would expect a correlation of approximately 0.32 since 10 per cent of the variance in the general in-
fant mortality is attributable to SIDS cases and the proportion of shared variance is r2 (r2 = 0.10, r = 0.32). Thus, under the null hypothesis that SIDS incidence rate is independent of the rate of all other (non-SIDS) causes of infant mortality, r = 0.32 should serve as the null hypothesis rather than the null hypothesis tested by Blok that r = 0. Another more direct means of overcoming this difficulty would be to calculate the rate of "non-SIDS infant mortality" for each city and county and then determine the correlation with SIDS rates. When Blok states that "the existence of a higher than average general infant mortality rate may likely be taken as an indication that a higher than average SIDS rate is also present" (p. 372), he is, in effect, elaborately restating the fact that 10 per cent of infant mortality is due to SIDS. What is of interest to this reader (ahd presumably to Blok as well) is whether or not the rate of SIDS correlates with other causes of infant mortality.
David A. Savitz Department of Preventive Medicine Ohio State University Columbus, OH43210 REFERENCE 1. Blok JH: The incidence of sudden infant
death syndrome in North Carolina's cities and counties: 1972-1974. Am J Public Health 68:367-372, 1978.
AJPH January 1979, Vol. 69, No. 1
