DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE

PUBLIC HEALTH SERVICE
NATIONAL INSTITUTES OF HEALTH
BETHESDA, MARYLAND 20014

 

FEB 8 1973

Honorable Gaylord Nelson
United States Senate
Washington, D.C. 20510

Dear Senator Nelson:

Since my earlier letter to you dated November 29, 1972, on the matter of

the possible etiologic impact of potato blight on the incidence of anencephaly
and spina bifida, I am able to report some progress in the planning and
initiation of research activities.

Outside of the Institute, Dr. Philip Cole of the Harvard School of Public
Health has already begun a case-control study in the State of Massachusetts.
He is mailing questionnaires to women who have given birth to babies with
spina bifida and to appropriately selected controls in order to determine
whether potato consumption rates differ in the two groups.

We are informed that Dr. Renwick, who recently summarized the epidemiologic
evidence in favor of the potato blight hypothesis, is planning a design
protocol for a prospective avoidance study to be carried out in England.
This study starts with the observation that women who have previously given
birth to babies with anencephaly and spina bifida have a relatively high
recurrence rate (about 5%). Thus, it is his plan to contact a group of
such women, urge them to avoid potatoes during any subsequent pregnancies
and then follow these women for a period of years.

Within the Institute, epidemiologists and biostatisticians have been seriously
considering different research approaches to acquiring more definitive data

on the hypothesis. These scientists have concluded that major, large scale
studies are not merited in view of the still tenuous nature of the evidence
supporting the potato blight hypothesis. I agree with their recommendation.
Certainly, well-controlled, randomized clinical trials must be ruled out
simply on the basis of ethical considerations. However, we are giving

serious attention to the possibility of less extensive studies and to the
continued exploitation of available records in order to obtain additional
confirmatory evidence.
Page 2

Thus, we are exploring the possibilities of performing a case-control

study in Egypt. This country is being considered because of the availability
of PL 480 funds and because of presumably low potato consumption. We are also
exploring the feasibility and need of a case-control study parallel to

the one being conducted at Harvard. Our cases and controls would, of

course, be selected from some other area.

During the past two months one of our epidemiologists has been investigating
available data in the United States in order to confirm the correlational
studies done earlier. Despite difficulties in obtaining reliable data

on potato blight from year to year and place to place, he has carried out
the following interesting analyses. The association between potato blight
and anencephaly/spina bifida appears to hold as one moves from East to
West with the occurrences of both phenomena being higher in the East and
lower in the West. However, the positive association breaks down along
North-South movements in the eastern United States where patterns of
potato losses due to blight and infant death rates due to spina bifida

are clearly in opposite directions. Furthermore, he found that in the
United States there is a definite absence of seasonal variation in the
reporting of these congenital malformations at birth. These observations
add to the weaknesses in Renwick's original argument which I pointed out
in my earlier letter.

In summary, the Institute's position at this time with regard to further
research of the potato blight problem is to engage in moderately sized
studies in the acquisition of more definitive data and secondly to continue
to analyze existing data to tighten and confirm the epidemiologic evidence.
If, as a consequence of any new findings, the evidence becomes much more
convincing than it is now, we shall then consider larger scale studies.

Finally, we anticipate receiving research proposals in this area from the
scientific community. Preliminary inquiries have already been made of
the Institute as to our interest in supporting research of the effect of
blighted potatoes in animals. We, of course, will invite such proposals.

Sincerely yours,

Gerald D. LaVeck, M.D.

Director

National Institute of Child Health
and Human Development