924
developed. This
series shows increases in national months after peak unemployment and eighteen before increases in mortality. These findings suggest that stress may be an important intermediary between unemployment and mortality. Secondly, a model was made to detect mortality associated with severe economic recession and depression. This model incorporated the hypothesis that ischxmic heart-disease is in part a point-source epidemic which can be traced to the extreme unemployment of the great depression. Thirdly, the links between medical therapeutics, unemployment, and mortality were also examined. The findings suggest that medical therapeutics has been associated with declining mortalityrates, contrary to past opinion4 and despite opposing economic factors. These economic factors are significant in Australia (e.g., a 1 :;, increase in unemployment has been followed by a 2.1 1%, increase in mortality). The "shades of Chadwick and his peers" (your editorial phrase) may need to be placed "on-call" after the current high
stress"
was
stress some
unemployment. 27 Walker Road, Wyoming, New South Wales 2250, Australia
REX BUNN
premature. We believe that further work is needed to establish the aetiology of the hypomagnessemia and its relationship to tissue magnesium status, before the long-term studies necessary to detect any significant benefit from Mg supplements on the vascular complications of diabetes are embarked upon. These would present enormous problems of design and evaluation. Departments of Medicine and Chemical Pathology.
St. George’s Hospital Medical School, London SW17
HUGH M. MATHER GERALD E. LEVIN
PERFORMANCE OF BLOOD-GLUCOSE METERS
SIR,-Much interest has been shown recently in home for diabetics. Four blood-glucose available in the U.K. for this purpose, all based on glucose-oxidase detector strips, three being operated with Ames ’Dextrostix’ and one with Boehringer ’Reflotest’ strips. A portable meter (’Glucocheck’) is now recommended and advertised as specifically suitable for patients’ home use.
blood-glucose monitoring meters are
PERFORMANCE OF BLOOD-GLUCOSE METERS
MAGNESIUM STATUS IN DIABETES
SIR,-Your editorial
Hypomagnessemia and Diabetic based on the important study of McNair and colleagues,5 has highlighted the association between hypomagnessemia and diabetes, which although noted many years ago6 has until recently been virtually ignored. We estimated plasma-magnesium (Mg) concentrations in 582 unselected diabetic outpatients and 140 control subjects in an attempt to estimate the overall incidence of hypomagnesxmia in diabetes, and found that 146 (25r) had values below those of all but one control subject.’ The mean plasma-Mg concentrations (± S.D.) in our diabetic patients (0-74 + 0.07 mmol/1) and control subjects (0-81 + 0.06 mmol/1) correspond well with those found by McNair and colleagues. Although hypomagnesxmia was more frequent in insulin-dependent diabetic patients (the group studied by McNair et al.), we found it to be common in non-insulin-dependent diabetic patients. Detailed clinical and biochemical associations with the hypomagnesxmia found in our patients will be presented elseon
Retinopathy (April 7),
where.8
However, as your editorial points out, plasma-Mg concentrations may be a poor guide to intracellular Mg status.9.1O Although De Leeuw and his colleagues" have recently demonstrated a significant reduction in trabecular bone-Mg content in insulin-dependent diabetic patients, there is little comparable data on soft-tissue content. We therefore measured leucocyte Mg content in 16 poorly-controlled insulin-dependent diabetic patients and 17 healthy control subjects. No significant difference was found between the two groups. We have thus no convincing evidence of concurrent soft-tissue Mg depletion in diabetes, but further studies on the Mg content of skeletal muscle and other soft tissue in diabetes are clearly indicated. We emphasise that a causal relationship between hypomagnesEemia and the vascular complications of diabetes-whether retinopathy or ischsemic heart-disease-has not yet been established, and the administration of Mg salts may therefore be 4 Hetzel, B. S Health and Australian
Society. Harmondsworth, Middlesex,
1974. 5. McNair, P, Christiansen, C., Madsbad, S., Lauritzen, E., Faber, O., Binder, C , Transbol, I Diabets, 1978, 27, 1075. 6. Stutzman, F L, Amatuzio, D S. J Lab Clin. Med. 1953, 41, 215. 7 Mather, H. M., Nisbet, J A., Burton, G H., Poston, G. J., Bailey, P. A, Pilkington, T R. E Diabetologia, 1978, 15, 254 8. Mather, H. M, Nisbet, J A., Burton, G. H, Poston, G. J., Bland, J. M., Bailey, P A., Pilkington, T. R. E. Clin. Chim. Acta (in the press). 9 Alfrey, A. C., Miller, N. L, Butkis, D. J Lab. Clin. Med 1974, 84, 153 10 Levin, G. E, Mather, H. M., Gazet, J.-C, Pilkington, T. R. E. Clin Chim
Acta, 1979, 92, 469
11. DeLeeuw, I., Vertommen, J. Abs
R
Biomedicine Express, 1978, 29, 16.
1
mmol/l glucose=18 mg,/dI. The aim of this useful innovation is to permit improved plascontrol in diabetics, particularly when they are It pregnant. is important, however, that the system used is capable of a reasonable degree of precision if it is to improve conventional urinalysis and visual interpretation of the dextrostix colour reaction. We have checked the precision of the four meters and show the results in the accompanying table. In our hands the imprecision of three of the meters was such that we would consider them unsuitable and possibly even misleading for patient use. The same three meters failed to warn when the sensitivity of the test system had been exceeded (i.e., plasma-glucose more than 20 mmol/1). Although the ’Hypocount’ meter has an inbuilt warning system, a plasma-glucose of 36 mmol/1 (Beckman) failed to activate this mechanism because the meter recorded the blood-glucose as approximately 17 mmol/1. Before home blood-glucose monitoring, which we accept is an advance, becomes standard practice, the performance of the meters and the relative merits of the test sticks should be further assessed. Precision must be tested-simply to show correlation between individual meter performances is not
ma-glucose
enough. Diabetic Clinic, Aberdeen Royal
Infirmary
Department of Chemical University of Aberdeen, Aberdeen AB9 2ZD
L.
J. BORTHWICK
Pathology, I. S. Ross
KARELA AND BLOOD-SUGAR
SIR,-I was surprised to see the note of caution in Mr Aslam and Dr Stockley’s report (March 17, p. 607) on an interaction between the popular Indian and Chinese vegetable karela bnter gourd, Momordica charantia) and chlorpropamide, an
developed. This
series shows increases in national months after peak unemployment and eighteen before increases in mortality. These findings suggest that stress may be an important intermediary between unemployment and mortality. Secondly, a model was made to detect mortality associated with severe economic recession and depression. This model incorporated the hypothesis that ischxmic heart-disease is in part a point-source epidemic which can be traced to the extreme unemployment of the great depression. Thirdly, the links between medical therapeutics, unemployment, and mortality were also examined. The findings suggest that medical therapeutics has been associated with declining mortalityrates, contrary to past opinion4 and despite opposing economic factors. These economic factors are significant in Australia (e.g., a 1 :;, increase in unemployment has been followed by a 2.1 1%, increase in mortality). The "shades of Chadwick and his peers" (your editorial phrase) may need to be placed "on-call" after the current high
stress"
was
stress some
unemployment. 27 Walker Road, Wyoming, New South Wales 2250, Australia
REX BUNN
premature. We believe that further work is needed to establish the aetiology of the hypomagnessemia and its relationship to tissue magnesium status, before the long-term studies necessary to detect any significant benefit from Mg supplements on the vascular complications of diabetes are embarked upon. These would present enormous problems of design and evaluation. Departments of Medicine and Chemical Pathology.
St. George’s Hospital Medical School, London SW17
HUGH M. MATHER GERALD E. LEVIN
PERFORMANCE OF BLOOD-GLUCOSE METERS
SIR,-Much interest has been shown recently in home for diabetics. Four blood-glucose available in the U.K. for this purpose, all based on glucose-oxidase detector strips, three being operated with Ames ’Dextrostix’ and one with Boehringer ’Reflotest’ strips. A portable meter (’Glucocheck’) is now recommended and advertised as specifically suitable for patients’ home use.
blood-glucose monitoring meters are
PERFORMANCE OF BLOOD-GLUCOSE METERS
MAGNESIUM STATUS IN DIABETES
SIR,-Your editorial
Hypomagnessemia and Diabetic based on the important study of McNair and colleagues,5 has highlighted the association between hypomagnessemia and diabetes, which although noted many years ago6 has until recently been virtually ignored. We estimated plasma-magnesium (Mg) concentrations in 582 unselected diabetic outpatients and 140 control subjects in an attempt to estimate the overall incidence of hypomagnesxmia in diabetes, and found that 146 (25r) had values below those of all but one control subject.’ The mean plasma-Mg concentrations (± S.D.) in our diabetic patients (0-74 + 0.07 mmol/1) and control subjects (0-81 + 0.06 mmol/1) correspond well with those found by McNair and colleagues. Although hypomagnesxmia was more frequent in insulin-dependent diabetic patients (the group studied by McNair et al.), we found it to be common in non-insulin-dependent diabetic patients. Detailed clinical and biochemical associations with the hypomagnesxmia found in our patients will be presented elseon
Retinopathy (April 7),
where.8
However, as your editorial points out, plasma-Mg concentrations may be a poor guide to intracellular Mg status.9.1O Although De Leeuw and his colleagues" have recently demonstrated a significant reduction in trabecular bone-Mg content in insulin-dependent diabetic patients, there is little comparable data on soft-tissue content. We therefore measured leucocyte Mg content in 16 poorly-controlled insulin-dependent diabetic patients and 17 healthy control subjects. No significant difference was found between the two groups. We have thus no convincing evidence of concurrent soft-tissue Mg depletion in diabetes, but further studies on the Mg content of skeletal muscle and other soft tissue in diabetes are clearly indicated. We emphasise that a causal relationship between hypomagnesEemia and the vascular complications of diabetes-whether retinopathy or ischsemic heart-disease-has not yet been established, and the administration of Mg salts may therefore be 4 Hetzel, B. S Health and Australian
Society. Harmondsworth, Middlesex,
1974. 5. McNair, P, Christiansen, C., Madsbad, S., Lauritzen, E., Faber, O., Binder, C , Transbol, I Diabets, 1978, 27, 1075. 6. Stutzman, F L, Amatuzio, D S. J Lab Clin. Med. 1953, 41, 215. 7 Mather, H. M., Nisbet, J A., Burton, G H., Poston, G. J., Bailey, P. A, Pilkington, T R. E Diabetologia, 1978, 15, 254 8. Mather, H. M, Nisbet, J A., Burton, G. H, Poston, G. J., Bland, J. M., Bailey, P A., Pilkington, T. R. E. Clin. Chim. Acta (in the press). 9 Alfrey, A. C., Miller, N. L, Butkis, D. J Lab. Clin. Med 1974, 84, 153 10 Levin, G. E, Mather, H. M., Gazet, J.-C, Pilkington, T. R. E. Clin Chim
Acta, 1979, 92, 469
11. DeLeeuw, I., Vertommen, J. Abs
R
Biomedicine Express, 1978, 29, 16.
1
mmol/l glucose=18 mg,/dI. The aim of this useful innovation is to permit improved plascontrol in diabetics, particularly when they are It pregnant. is important, however, that the system used is capable of a reasonable degree of precision if it is to improve conventional urinalysis and visual interpretation of the dextrostix colour reaction. We have checked the precision of the four meters and show the results in the accompanying table. In our hands the imprecision of three of the meters was such that we would consider them unsuitable and possibly even misleading for patient use. The same three meters failed to warn when the sensitivity of the test system had been exceeded (i.e., plasma-glucose more than 20 mmol/1). Although the ’Hypocount’ meter has an inbuilt warning system, a plasma-glucose of 36 mmol/1 (Beckman) failed to activate this mechanism because the meter recorded the blood-glucose as approximately 17 mmol/1. Before home blood-glucose monitoring, which we accept is an advance, becomes standard practice, the performance of the meters and the relative merits of the test sticks should be further assessed. Precision must be tested-simply to show correlation between individual meter performances is not
ma-glucose
enough. Diabetic Clinic, Aberdeen Royal
Infirmary
Department of Chemical University of Aberdeen, Aberdeen AB9 2ZD
L.
J. BORTHWICK
Pathology, I. S. Ross
KARELA AND BLOOD-SUGAR
SIR,-I was surprised to see the note of caution in Mr Aslam and Dr Stockley’s report (March 17, p. 607) on an interaction between the popular Indian and Chinese vegetable karela bnter gourd, Momordica charantia) and chlorpropamide, an
