In \Ieclicine one must pay attention not to 1)hIUSil)lc tlworizing but to (.xperience ilI1(l rCaSOfl together. . . . I agree that theorizing is to l)(’ approved, l)r\ilc(l that it is based on facts, and
systematically make its deductions from what is observed. . . . But conclusions drawn from
unaided reason can hardly be serviceable; only those drawn from observed fact.” Hippocratts: Precepts.
S #{149} #{149}
(
This heading and text scent appropriate fo; a section of s/tort communications requiring onit,rapid editorial reek’w arlci little, if ant/, reci.sion. it is /lopc’(l that soc/i factual material may thus
be published almost OS promptly (IS tile OflOflS, coinriieitts, (111(1 criticisnis which will continue to
appear as Letters to the Editor.
.____j
L
4#{149}JUNE 42C I T Y “M:
ONE BLOCK AREA OF HIOH INCIDENCE
a
Experience
and Reason
Briefly
Recorded
An
Increased
Incidence
of
Spina
Bifida
in Vermont
in
1962
Our interest in the incidence of spina bifida
in Vermont was aroused by four infants with
this anomaly who were referred to the teaching hospitals of the University of Vermont College
of Medicine in 1962 and early 1963. These four
children came from a one-block area in a city
of 8,700 population located in central Vermont
(
Fig. 1). Three were born within a six-weekperiod in late June and early August, 1962. The
fourth was born in February, 1963. All of the
children were delivered by the same physician.
This cluster of births of infants with severe
spinal cord abnormalities caused considerable local concern and speculation.
During 1962, we also had the clinical
illl-pression that an increased number of infants
with spina bifida was being referred to the
two teaching hospitals of the University of
Vermont from other areas in the state. This
impression, together with the cluster of infants
already mentioned, led us to cariy out a retro-spective study designed to answer the question:
“Has there been an increase in the incidence of
spina bifida in Vermont in recent years?”
METHODS
For the purposes of definition in this article
the term spina bifida includes spina bifida cys-tica, meningocele, meningomyelocele,
myelo-cele, and encephalocele. These conditions may
be accompanied by hydrocephalus initially or
as a complication. Spina bifida occulta has not
been included because of the difficulties of
diagnosis and accurate ascertainment.
FIc. 1. Cluster of cases of spina bifida in City “M” in Vermont.
As a baseline for comparison with the
re-ported incidences from other areas the number of affected infants born per 100,000 live births was used. Abortions and stillbirths were not
in-eluded. The study was retrospective, and
coy-ered the 11-year period 1952-1962 inclusive.
The sources used for ascertainment were the
birth and death certificates of the Vermont
State Health Department (birth certificates in
Vermont have included a separate section
de-voted to congenital anomalies since 1941), the
records of the DeGoesbriand Memorial and
Mary Fletcher Hospitals in Burlington (23% of
Vermont births during the 11-year period
oc-curred in these two hospitals), the records of
the Division of Neurosurgery of the University
of Vermont College of Medicine, and the
rec-ords of the Child Health Services Division of
TABLE I
YEARLY INCIDENCE OF SPINA BIFIDA IN VERMONT
0 ,0 00 .0 zC - VE4MONT
0--0
NEW HAMPSHIREI’J H) 0) - ED n0- I’J
Jo . 0) A) A) ID SD IC
FIG. 2
982 INCREASE OF SPINA BIFIDA
Year Live Births
Cases of Spina Bifida Incidence per 100,000 Live Births 195 1953 1954 1955 1956 1957 1958 1959 1960 1961 9,010 9,166 9,16 9,00 9,082 9,300 9,45 9,301 9,79 9,94 8 11 11 18 8 6 5 14 4 11 89 U20 1q20 141 88 65 54 150 43 119 10-year ‘Fotal 196 91 ,958 9,039 91 1 Average 99 E23
Total 100,997 112
the Vermont State Health Department which
offers a well-known and widely used program
of aid for handicapped children, including those
with congenital defects of the central nervous
system. In addition to these sources of
informa-lion letters were written to every physician in
the state outside of the Burlington area (432),
requesting the names of any children born with
spina bifida during the years 1960-1962.
Re-plies were received from 90% of the physicians
polled.
The use of these multiple sources of
ascer-tainment served to minimize, but certainly not
to eliminate, the problem of under-reporting.
This congenital defect, because it is obvious
and dramatic, is one in which reporting tends
to be more reliable than for other less obvious
congenital anomalies. Gittlesohn and Milham2
stulied this point and demonstrated that one
can expect about 85% reporting of this
partidu-lar anomaly from the first two of the six sources
that we employed.
Using these multiple sources of information
a total of 112 cases of spina bifida were
ascer-tamed to have occurred in Vermont during the
period 1952-1962 among a total of 100,997
live births. All but 17 of the 112 cases had been
reported on birth certificates. If the assumption
is made that our multiple-source method
re-sulted in 100% ascertainment, one could also
assume 85% complete reporting on birth
certifi-cates, the same range of completeness found by
Gitflesohn and Milham2 their study of New
York State.
RESULTS
Table I is a summary of the yearly incidence
of spina bifida in Vermont during the years
1952-1962. Figure 2 depicts these data and
compares them to the yearly incidence figures
reported from New Hampshire.3
These data support our clinical suspicion and
hypothesis that there was an increased
mci-dence of live-born children with spina bifida in
Vermont during 1962. The “normal” incidence
for Vermont during the period 1952-1961 was
91 in 91,415 live births or 99 per 100,000 live
births. This figure is in good agreement with
the reported mean incidence of this defect (99
per 100,000 live births) from other areas of the
world. These data are summarized in Table
11.2, 4-8 During 1962 in Vermont there were 21 cases of spina bi.fida among 9,039 live births or
232 per 100,000 live births. The difference
be-tween this incidence and the mean for
1952-1961 is statistically significant at the .001 level.1
Gittelsohn and Milham2 have reported a 50%
decline in the incidence of spina bifida over the
period 1945-1959 in New York State. Milham
has not observed any change in the incidence
of this congenital anomaly during 19591962.8
Dr. Gilbert Mel1in has not observed any
change in its incidence in lower New York State during 1946-1962. Vermont’s recent experience is, therefore, quite different from that of its two neighboring states and from that previously re-ported from other areas of the world.
COMMENT
Previous 1 in reviewing the
TABLE
11*
REPORTED INCIDENCE OF SPINA BIFIDA FROM TIlE LITERATURE (1, 8-7)
Author
Harris
Area Live-Birth
Popv-lation at Risk
Period (yr)
Rate/100,000 Live Births
Rochester, Minn. 8,716 1944-1950 260
Schwidde Iowa City, Iowa 483,028 1941-1949 87
Pleydell Northamptonshire, England 60 ,890 19441957 116
Boris Atlant, Ga. (Negro) 57,634 1952-1961 33
Boris Atlanta, Ga. (\Vhite) 129,833 1952-1961 76
Milham Upstate New York 90 ,844 1962 (8 months) 126
Gittelsohn Upstate New York 2 ,55’2 ,910 19451959 100
EXPERIENCE AND REASON-BRIEFLY RECORDED 983
8,867
6 Weighted mean incidence= =99.5.
3,387.855
demiology of spina bifida, have called attention
to several factors which are believed to affect
the incidence of this anomaly. These factors are
listed in Table Ill.
The general impression of most workers is
that environment plays a larger role in the
eti-ology of this deformity than does either heredity
or chance mutation. The association with birth
order, seasonal variation in incidence, and an
increased frequency of cases in the lower
socio-economic groups are consistent with the
opera-tion of environmental factors. The low, although
definite, family incidence and discordance
be-tween monozygotic twins argue against any
simple genetic hypothesis as a full explanation of the occurrence of spina bifida.10
With these factors in mind a small
epidemi-ologic study was carried out of the 1 1 children
born with spina bifida in 1961 and the 21
chil-dren born with this defect in 1962. The authors
personally interviewed the parents and
physi-cians of 28 of these 32 children. The interviews
were primarily concerned with questions
re-garding events and medications taken during
the mother’s first trimester of pregnancy. There
were three families in which another sibling
had a central nervous system anomaly. Sixteen
of the 21 mothers of the infants born in 1962
took some medication during the first trimester
of their pregnancy. These included aspirin,
vita-mins, antihistamines, antiemetics, antibiotics,
minerals, contraceptive foam, and gamma
glob-ulin.
It
has been reported that the majority ofpregnant women take an average of four
medi-cations of this general nature during the first
trimester of pregnancy. No evidence was found
to incriminate any medication as an etiologic
agent in this very small series.
There were no epidemics of any common or
unusual viral infections reported to the
Ver-mont State Health Department during the early
post-conception period of these infants.
Four-teen of the 21 infants are estimated to have
been conceived during July-December, 1961.
Segall12 has studied the population exposure to
background radiation in northern New England
during this time period and found only small
differences in radiation exposure.
This is the second report in the literature
call-ing attention to a local increase in the incidence of spina bifida occuring in 1962. Boris et al.7
reported a peak incidence of 16 infants among
3,630 births or 441 per 100,000 live births
during the months of August-October, 1962, in
Atlanta, Georgia. Our similar observations lend
support to their hypothesis of a local “epidemic”
having occurred in 1962. Mellin points out that
“the haunting question which reoccurs is
whether this fluctuation in incidence rates is
due to chance or change.”#{176} The small cluster
TABLE III
FACTORS AFFECTING THE INCIDENCE OF SPINA BIFIDA
Factor Effect
Race Decreased in nonwhites
Sex Increased in females
Geographic Variable
Genetic Familial incidence
First pregnancy Increased
Socioeconomic p
Seasonal p
Influenza ?
-984 WARM NAPE OF NEWBORN
of cases that we observed, and our independent
observation of an increased incidence of this
defect in Vermont during the same time period
as the “epidemic” in Atlanta, Georgia,
encour-ages us to believe that this is not due to chance.
We hope that this report will encourage others
to look into the problem.
Preliminary observations indicate that 1963
was a year of normal incidence for spina bifida
(9,000
live births, 14 cases of spina bifida or 150 per 100,000 live births).This finding, along with the normal incidence
in 1961, indicates that the high incidence in
1962 is not due to our extra efforts to get
corn-plete reporting or to the effects of recent
rnern-orv recall on reporting during the 1961-1963
period.
SUMMARY
An increased incidence of spina bifida among
live-born infants in Vermont during 1962 has
been observed and documented. The average
incidence for this congenital anomaly during
the period 1952-1961 was 99 per 100,000 live
births; in 1962 it increased to 232 per 100,000 live births. This is the second report of such an
occurrence in the United States during 1962.
Epidemiologic studies failed to reveal any
clues as to a possible teratologic agent.
J
EROLDF.
LUCEY, M.D.ROBERT
W.
MANN,C.
MILLARD SIMMONSEDWARD FRIEDMAN,
M.D.
Department of Pediatrics,
University of Vermont College
of Medicine, Vermont State Health
Department
Burlington, Vermont
This study was aided by a donation from Rev.
and Mrs. T. Euson to the Neurosurgical Research Fund of the Division of Neurosurgery, University
of Vermont College of Medicine. We wish to
thank Mr. D. Bergstrom of the Vermont State
Health Department and Dr. L. Wailman for their
generous help and co-operation.
REFERENCES
1. Ferguson, G. A. : Statistical Analysis, New
York: McGraw-Hill, 1959, pp. 146-148.
2. Gittelsohn, A. M., and Milham, S.: Declining
incidence of central nervous system
ano-malies in New York State. Brit. J. Prey.
Med., 16:153, 1962.
3. Personal communication: M. A. Atchison,
M.D., M.P.H., Director of Public Health,
Department of Health and Welfare, State
of New Hampshire, July 3, 1962.
4.
Harris, L., and Steinberg, A. : Anomalies ob-served during the first six days of life in 8,716 live-born infants. PmIAmIcS, 14:314, 1954.5. Schwidde, J. T. : Spina bifida. Amer. J. Dis. Child., 84:35, 1952.
6. Pleydell, M. J.: Anencephaly and other
con-genital anomalies. Brit. Med. J., 1:309,
1960.
7. Boris, M., Blumberg, R., Feldman, D. B., et al.: Increased incidence of meningomyelo-celes, J.A.M.A., 184:768, 1963.
8. Milham, S.: Personal communication, July 16, 1963.
9. Mellin, G., and Katzenstein, NI. : Increased
incidence of malformations chance or
change? J.A.M.A. (in press).
10. Edwards, J. H. : Congenital malformations of
the central nervous system in Scotland.
Brit. J. Prey. Soc. Med., 12:115, 1958.
1 1. Doran, P. A., and Guthkelch, A. N. : The
epidemiology of spina bifida. Dev. Med. Child. Neurol., 4:307, 1962.
12. SegalI, A. : Radiogeology and population
ex-posure to background radiation in northern New EngI. Sci., 140:1337, 1963.
Warm
Nape
of the
Newborn
R. E.
Smith recently made an intriguingsug-gestion concerning thermal control in the
new-born. He noted the distribution of brown
adi-pose tissue in the neonatal mouse (dorsal
cervi-cal and interscapular, among other areas) and
he considered significant the fact that this
tis-sue is distributed close to the confluence of
veins draining the periphery. Since the
meta-bolic activity of brown fat is known to be quite
high, Smith proposed that this tissue
repre-sents a thermogenic jacketing of vascular
re-turn from the cool surface, maintaining a
rela-tively warm flow of blood to the heart and
central nervous system. Moreover, it has been
demonstrated that circulation is increased in
brown adipose tissue when norepinephrine is
infused into a cold acclimated rat, and these
areas of brown fat show an immediate thermal response, by direct temperature measurement,
when the animal is stimulated by
norepi-nephrine or by a decrease in ambient
tempera-hire.1
Aided by grants (1-181 and U-1118) from the
health Research Council of the City of New York
