107 "
random data. With such a noisy background ", the value of 0.80 is less impressive than might seem. Knowledge of the true nature of the relation between Pacû2 and plasma-bicarbonate concentration requires the measurement of both those
of mild
to severe
variables, throughout the range single-factor disturbances. Given the
of the universal correctness of theconstants ’ calculate plasma-bicarbonate concentrationthe accurate measurement of that quantity in blood awaits the development of bicarbonate-activity electrodes. Meanwhile, we suggest that the coordinates chosen for acid-base diagrams should use measured primary data rather than derived values, and, if possible, illuminate significant physiological relations. If the" relation between Paco., and either arterial blood-pH or H+ concentration ", has the potential of providing physiological insights that may be obscured by the nearly straight-line relations between Paco, and calculated plasma-bicarbonate, why decline the dividend ?
uncertainty used
to
Albert Einstein College of Medicine, Bronx Municipal Hospital Center, New York, New York 10461, U.S.A.
MILFORD FULOP MICHAEL FULOP.
CALCIUM BALANCE IN PREGNANCY
Sm,—From the results of their short-term studies on calcium balance in pregnancy, Duggin et al. (Oct. 19, p. 926) suggested that the intake of the element during pregnancy should be 2 g. rather than 1 g. per day. They believe this intake to be desirable; otherwise, the loss to the fetus is " potentially detrimental to bones and teeth". No references were given to situations where such stigmata have been observed and were thought to be attributable to an inadequate intake of the element. Only a small proportion of mothers, even in Western countries, have an intake of 2 g. calcium per day during pregnancy; among less privileged populations the proportion is insignificant. Yet it is among the latter populations that families are large and long lactations the rule. Moreover, this state of affairs also prevailed among White populations in the not too distant past. To what extent has calcium lack, whether in the fetus or the life-span of the mother, been manifested by demineralised bones and teeth ? In South Africa we have sought to throw light on this issue by studying extremes of populations. We determined cortical thickness and other cortical scores of second metacarpal and humerus in series of Black and White mothers, each ethnic group being subdivided into groups who had (1) huge families (average about 9 children) and (2) none or 1 or 2 children. Mean calcium intake was about 0’35 g. for the Blacks, and about 06 g. for the Whites. Yet mean cortical data for the four groups were closely similar.1 Like observations have been reported from Columbia2 and Sweden.3 We have also carried out studies on groups of elderly Black males and females, accustomed throughout life to a low calcium intake, and found their data for second metacarpal to be closely similar to those reported for elderly Whites.4 Among the elderly Black mothers studied, no significant differences were found in cortical thickness and other scores between those wbo had had (1) 7-20 children and (2) 2-6 children. What criteria must be applied before accepting the existence of a nutritional deficiency disease whose presence demands correction by the individual or even intervention 1.
2.
Walker, A. R. P., Richardson, B. D., Walker, B. F. Clin. Sci. 1972, 42, 189. Suttapreyasri, D. Dr P.H. Thesis, Columbia University, New York, 1968.
3. 4.
Nilssen, B. E. Surgery Gynec. Obstet. 1969, 129, 27. Walker, A. R. P., Walker, B. F., Richardson, B. D. Postgrad. med. J. 1971, 47, 320.
by public-health authorities ? Yudkin’s5 requirements are: (1) evidence of deficient intake or utilisation, primary or conditioned, of the nutrient; (2) signs and symptoms specific for the particular deficiency ; and (3) prevention or Proof is cure following correction of the deficiency. required of a detectable improvement in wellbeing after an increase in the intake of the nutrient. Specific evidence is lacking which demonstrates unequivocally that pregnant women are at a health disadvantage because of inadequate calcium intake, or that their health, and that of their offspring, would be detectably benefited by ingestion of additional calcium during pregnancy and lactation. This lack of knowledge is extremely humbling, bearing in mind that the situation in question involves (often repeatedly) most of the world’s female population, and thus requires no elaborate set-up for testing. In 1965, a W.H.O. Expert Committee 6 stated: " The Committee wishes to emphasize that the areas of ignorance relating to nutrition in pregnancy and lactation are extremely large, and it is impossible as a rule to state didactically that this or that particular form of dietary change will produce a specific effect." In nutritional science we are going through a period of critical reappraisal of nutrient needs and deficiencies. Witness the present vehement 7 controversy over protein intake and protein deficiency. The July issue (special supplement) of Nutrition Reviews 8 is composed almost wholly of debunking articles. To return, recommendations for increases in calcium intake in pregnancy and lactation are plausible; yet evidence of consequent benefits to health is lacking. M.R.C. Human Biochemistry Research Unit, South African Institute for Medical Research, Johannesburg, South Africa.
ALEXANDER R. P. WALKER.
TEMPORARY PARALYSIS IN CHILDHOOD AFTER INFLUENZA B
SIR,-Iwas interested to read the article by Dr Stevens colleagues (Dec. 7, p. 1354) concerning temporary paralysis in children after influenza B. During March of last year there was a local epidemic within our practice area. Two children were seen by myself and one of my partners with a clinical presentation very similar to that described by Dr Stevens and his associates. and his
A 10-year-old boy had clinical symptoms of influenza but in addition considerable tenderness of calf muscles and inability to walk. He was seen two days later by which time the power had returned in his legs and he was well except for a residual cough. The other patient was a 71-year-old boy who had been seen the previous day with a 2-day history of coryza and non-productive cough which was thought to be influenza. The following day he had pain and tenderness in his calves and inability to walk, but the generalised symptoms of his infection seemed to be settling. There were no abnormal findings except calf tenderness and weakness in the lower limbs. He was seen on a domiciliary visit by a consultant neurologist. He diagnosed a polyneuritis. This as with the other child resolved in 48 hours and he remained free of trouble. Since there was a family history of spina bifida, X-ray examination of the lower spine was done and it was normal.
I have contacted the local Public Health Laboratory and they tell me that both influenza A and B were prevalent during last winter, but unfortunately they are unable to tell me what the local epidemic in our area was at the time when these 2 children presented. I understand from per-
sonal communication with Dr Stevens that their cases were seen at the end of February, 1974, during a local epidemic, 5. Yudkin, J. Practitioner, 1961, 187, 150. 6. Wld Hlth Org. tech. Rep. Ser. 1965, no. 302. 7. McLaren, D. S. Lancet, 1974, ii, 93. 8. Nutr. Rev. 1974, 32 (special supplement).
random data. With such a noisy background ", the value of 0.80 is less impressive than might seem. Knowledge of the true nature of the relation between Pacû2 and plasma-bicarbonate concentration requires the measurement of both those
of mild
to severe
variables, throughout the range single-factor disturbances. Given the
of the universal correctness of theconstants ’ calculate plasma-bicarbonate concentrationthe accurate measurement of that quantity in blood awaits the development of bicarbonate-activity electrodes. Meanwhile, we suggest that the coordinates chosen for acid-base diagrams should use measured primary data rather than derived values, and, if possible, illuminate significant physiological relations. If the" relation between Paco., and either arterial blood-pH or H+ concentration ", has the potential of providing physiological insights that may be obscured by the nearly straight-line relations between Paco, and calculated plasma-bicarbonate, why decline the dividend ?
uncertainty used
to
Albert Einstein College of Medicine, Bronx Municipal Hospital Center, New York, New York 10461, U.S.A.
MILFORD FULOP MICHAEL FULOP.
CALCIUM BALANCE IN PREGNANCY
Sm,—From the results of their short-term studies on calcium balance in pregnancy, Duggin et al. (Oct. 19, p. 926) suggested that the intake of the element during pregnancy should be 2 g. rather than 1 g. per day. They believe this intake to be desirable; otherwise, the loss to the fetus is " potentially detrimental to bones and teeth". No references were given to situations where such stigmata have been observed and were thought to be attributable to an inadequate intake of the element. Only a small proportion of mothers, even in Western countries, have an intake of 2 g. calcium per day during pregnancy; among less privileged populations the proportion is insignificant. Yet it is among the latter populations that families are large and long lactations the rule. Moreover, this state of affairs also prevailed among White populations in the not too distant past. To what extent has calcium lack, whether in the fetus or the life-span of the mother, been manifested by demineralised bones and teeth ? In South Africa we have sought to throw light on this issue by studying extremes of populations. We determined cortical thickness and other cortical scores of second metacarpal and humerus in series of Black and White mothers, each ethnic group being subdivided into groups who had (1) huge families (average about 9 children) and (2) none or 1 or 2 children. Mean calcium intake was about 0’35 g. for the Blacks, and about 06 g. for the Whites. Yet mean cortical data for the four groups were closely similar.1 Like observations have been reported from Columbia2 and Sweden.3 We have also carried out studies on groups of elderly Black males and females, accustomed throughout life to a low calcium intake, and found their data for second metacarpal to be closely similar to those reported for elderly Whites.4 Among the elderly Black mothers studied, no significant differences were found in cortical thickness and other scores between those wbo had had (1) 7-20 children and (2) 2-6 children. What criteria must be applied before accepting the existence of a nutritional deficiency disease whose presence demands correction by the individual or even intervention 1.
2.
Walker, A. R. P., Richardson, B. D., Walker, B. F. Clin. Sci. 1972, 42, 189. Suttapreyasri, D. Dr P.H. Thesis, Columbia University, New York, 1968.
3. 4.
Nilssen, B. E. Surgery Gynec. Obstet. 1969, 129, 27. Walker, A. R. P., Walker, B. F., Richardson, B. D. Postgrad. med. J. 1971, 47, 320.
by public-health authorities ? Yudkin’s5 requirements are: (1) evidence of deficient intake or utilisation, primary or conditioned, of the nutrient; (2) signs and symptoms specific for the particular deficiency ; and (3) prevention or Proof is cure following correction of the deficiency. required of a detectable improvement in wellbeing after an increase in the intake of the nutrient. Specific evidence is lacking which demonstrates unequivocally that pregnant women are at a health disadvantage because of inadequate calcium intake, or that their health, and that of their offspring, would be detectably benefited by ingestion of additional calcium during pregnancy and lactation. This lack of knowledge is extremely humbling, bearing in mind that the situation in question involves (often repeatedly) most of the world’s female population, and thus requires no elaborate set-up for testing. In 1965, a W.H.O. Expert Committee 6 stated: " The Committee wishes to emphasize that the areas of ignorance relating to nutrition in pregnancy and lactation are extremely large, and it is impossible as a rule to state didactically that this or that particular form of dietary change will produce a specific effect." In nutritional science we are going through a period of critical reappraisal of nutrient needs and deficiencies. Witness the present vehement 7 controversy over protein intake and protein deficiency. The July issue (special supplement) of Nutrition Reviews 8 is composed almost wholly of debunking articles. To return, recommendations for increases in calcium intake in pregnancy and lactation are plausible; yet evidence of consequent benefits to health is lacking. M.R.C. Human Biochemistry Research Unit, South African Institute for Medical Research, Johannesburg, South Africa.
ALEXANDER R. P. WALKER.
TEMPORARY PARALYSIS IN CHILDHOOD AFTER INFLUENZA B
SIR,-Iwas interested to read the article by Dr Stevens colleagues (Dec. 7, p. 1354) concerning temporary paralysis in children after influenza B. During March of last year there was a local epidemic within our practice area. Two children were seen by myself and one of my partners with a clinical presentation very similar to that described by Dr Stevens and his associates. and his
A 10-year-old boy had clinical symptoms of influenza but in addition considerable tenderness of calf muscles and inability to walk. He was seen two days later by which time the power had returned in his legs and he was well except for a residual cough. The other patient was a 71-year-old boy who had been seen the previous day with a 2-day history of coryza and non-productive cough which was thought to be influenza. The following day he had pain and tenderness in his calves and inability to walk, but the generalised symptoms of his infection seemed to be settling. There were no abnormal findings except calf tenderness and weakness in the lower limbs. He was seen on a domiciliary visit by a consultant neurologist. He diagnosed a polyneuritis. This as with the other child resolved in 48 hours and he remained free of trouble. Since there was a family history of spina bifida, X-ray examination of the lower spine was done and it was normal.
I have contacted the local Public Health Laboratory and they tell me that both influenza A and B were prevalent during last winter, but unfortunately they are unable to tell me what the local epidemic in our area was at the time when these 2 children presented. I understand from per-
sonal communication with Dr Stevens that their cases were seen at the end of February, 1974, during a local epidemic, 5. Yudkin, J. Practitioner, 1961, 187, 150. 6. Wld Hlth Org. tech. Rep. Ser. 1965, no. 302. 7. McLaren, D. S. Lancet, 1974, ii, 93. 8. Nutr. Rev. 1974, 32 (special supplement).
