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A note on race-specific congenital malformation rates
CURRENT OPINION Pertinent comments
A note on race-specific congenital malformation rates TODD
M.
FRAZIER,
Sc.M.
Baltimore, Maryland
A R E v 1 E w of congenital malformation rates derived from information on birth certificates submitted to the Baltimore City Health Department agrees with previous reports1• 2 in the finding that polydactylism occurs far more often among Negro babies than among white babies. The purpose of this note is to present race-specific rates for all reported anomalies and for congenital malformations, excluding polydactylism. During the 5 year period, 1954-1958, there were 120,127 live births among the resident population of Baltimore, a city of nearly a million inhabitants. A physician or midwife attending a delivery is required to submit to the Baltimore City Health Department a birth certificate which, in addition to identifying information, includes a question concerning the presence of and type of congenital malformations noted at birth. To the extent that malformations are recognized and reported, the birth certificate provides a source of information concerning the incidence of anomalies among deliveries in an unselected population. Because of underre-
porting of malformations on birth certificates, the rates reported herein should be interpreted as an underestimate of the true frequency in a general population. Table I shows congenital malformation rates for live births among Baltimore residents during the period 1954-1958. The nonresident births, which include difficult obstetrical cases referred to the city's medical centers, have been excluded. Among the 71,032 white babies born there were 477 with malformations reported, a rate of 6.8 per 1,000 live births. The corresponding rate for the 49,095 non-white babies was 7.9 per 1,000 live births. Thus, for all reported congenital malformations the rate for the Negro race is about 16 per cent greater than the rate for the White race. If malformations of "bone and joint" (International Statistical Classification No. 758) are excluded, the race-specific rates are 4.8 for white babies and 3.0 for Negroes. Bone and joint malformation rates are 2.0 and 4.9 per 1,000 for the white and non-white, respectively, indicating more than a twofold increase in malformations of this general type among Negro infants. A search of the 388 birth certificates for which bone and joint malformations were
From the Department of Obstetrics, johns Hopkins University and Hospital, and the Bureau of Biostatistics, Baltimore City Health Department.
184
Volume 80 Number 1
Pertinent comments
185
Table I. Selected congenital malformation rates by race Type of malformation
All malformations except bone and joint Malformation of bone and joint Polydactylism All other bone and joint malformations
Rate per I ,000 live fli1ths
Number Total
White
333 144
478 388 200
21
188
123
Total 866 Malformation rate excluding polydactylism
reported revealed that, of the 244 anomalies of this type among non-whites, 179, or about 74 per cent, were births in which polydactylism was reported. The incidence of this malformation among Negroes was 3.6 per 1,000 live births, a twelvefold increase over the rate of 0.3 per 1,000 noted for white infants. The incidence of all other bone and joint malformations was approximately the same in the two races. The last line of Table I shows the racespecific malformation rates obtained when polydactylism is excluded. Here the rate for white live births, 6.5 per 1,000, is about 50 per cent greater than the rate of 4.3 obtained for non-white births. When all reported malformations are included, the Negro malformation rate is higher than the rate for white infants-7.9 compared to 6.8
[Non-white
Total
145 244 65
White
1"
!on-w tie
4.8
3.0
3.3
~!.0
4.9
0.3
:).f)
1.7
1.6 389
r------~~---··--·h·:-:-
4.0
1.7
179
477
I
1.3
7.3 -·-
6.8 6.5 ------~--
----
7.9 4.:l
per 1,000 births. When polydactylism is excluded, the congenital malformation rate is higher for the white race-6.5 compared to 4.3 per 1,000 for Negroes. The possibility of observer differences must be considered. Thus, if there was a tendency for the Negro patients to be attended by less astute observers, then polydactylism might be noted whereas other more subtle anomalies might be missed. The only direct evidence against such observer bias rests in the statistics from the Johns Hopkins Hospital ·where, with the same or comparable observers for the two racial groups, the statistical difference noted for the entire sample also pertains. Thus, the greater incidence of congenital malformations can be awarded to either the Negro or the white race depending on the inclusion or exclusion of polydactylism.
REFERENCES
1. Wallace, H. M., Baumgartner, L., and Rich, H.: Pediatrics 12: 525, 1953. 2. Barsky, A. J: Congenital Anomalies of the
Hand and Their Surgical Treatment, American Lecture Series, No. 311, Springfield, IlL, 1958, Charles C Thomas, Publisher.
A note on race-specific congenital malformation rates TODD
M.
FRAZIER,
Sc.M.
Baltimore, Maryland
A R E v 1 E w of congenital malformation rates derived from information on birth certificates submitted to the Baltimore City Health Department agrees with previous reports1• 2 in the finding that polydactylism occurs far more often among Negro babies than among white babies. The purpose of this note is to present race-specific rates for all reported anomalies and for congenital malformations, excluding polydactylism. During the 5 year period, 1954-1958, there were 120,127 live births among the resident population of Baltimore, a city of nearly a million inhabitants. A physician or midwife attending a delivery is required to submit to the Baltimore City Health Department a birth certificate which, in addition to identifying information, includes a question concerning the presence of and type of congenital malformations noted at birth. To the extent that malformations are recognized and reported, the birth certificate provides a source of information concerning the incidence of anomalies among deliveries in an unselected population. Because of underre-
porting of malformations on birth certificates, the rates reported herein should be interpreted as an underestimate of the true frequency in a general population. Table I shows congenital malformation rates for live births among Baltimore residents during the period 1954-1958. The nonresident births, which include difficult obstetrical cases referred to the city's medical centers, have been excluded. Among the 71,032 white babies born there were 477 with malformations reported, a rate of 6.8 per 1,000 live births. The corresponding rate for the 49,095 non-white babies was 7.9 per 1,000 live births. Thus, for all reported congenital malformations the rate for the Negro race is about 16 per cent greater than the rate for the White race. If malformations of "bone and joint" (International Statistical Classification No. 758) are excluded, the race-specific rates are 4.8 for white babies and 3.0 for Negroes. Bone and joint malformation rates are 2.0 and 4.9 per 1,000 for the white and non-white, respectively, indicating more than a twofold increase in malformations of this general type among Negro infants. A search of the 388 birth certificates for which bone and joint malformations were
From the Department of Obstetrics, johns Hopkins University and Hospital, and the Bureau of Biostatistics, Baltimore City Health Department.
184
Volume 80 Number 1
Pertinent comments
185
Table I. Selected congenital malformation rates by race Type of malformation
All malformations except bone and joint Malformation of bone and joint Polydactylism All other bone and joint malformations
Rate per I ,000 live fli1ths
Number Total
White
333 144
478 388 200
21
188
123
Total 866 Malformation rate excluding polydactylism
reported revealed that, of the 244 anomalies of this type among non-whites, 179, or about 74 per cent, were births in which polydactylism was reported. The incidence of this malformation among Negroes was 3.6 per 1,000 live births, a twelvefold increase over the rate of 0.3 per 1,000 noted for white infants. The incidence of all other bone and joint malformations was approximately the same in the two races. The last line of Table I shows the racespecific malformation rates obtained when polydactylism is excluded. Here the rate for white live births, 6.5 per 1,000, is about 50 per cent greater than the rate of 4.3 obtained for non-white births. When all reported malformations are included, the Negro malformation rate is higher than the rate for white infants-7.9 compared to 6.8
[Non-white
Total
145 244 65
White
1"
!on-w tie
4.8
3.0
3.3
~!.0
4.9
0.3
:).f)
1.7
1.6 389
r------~~---··--·h·:-:-
4.0
1.7
179
477
I
1.3
7.3 -·-
6.8 6.5 ------~--
----
7.9 4.:l
per 1,000 births. When polydactylism is excluded, the congenital malformation rate is higher for the white race-6.5 compared to 4.3 per 1,000 for Negroes. The possibility of observer differences must be considered. Thus, if there was a tendency for the Negro patients to be attended by less astute observers, then polydactylism might be noted whereas other more subtle anomalies might be missed. The only direct evidence against such observer bias rests in the statistics from the Johns Hopkins Hospital ·where, with the same or comparable observers for the two racial groups, the statistical difference noted for the entire sample also pertains. Thus, the greater incidence of congenital malformations can be awarded to either the Negro or the white race depending on the inclusion or exclusion of polydactylism.
REFERENCES
1. Wallace, H. M., Baumgartner, L., and Rich, H.: Pediatrics 12: 525, 1953. 2. Barsky, A. J: Congenital Anomalies of the
Hand and Their Surgical Treatment, American Lecture Series, No. 311, Springfield, IlL, 1958, Charles C Thomas, Publisher.