Tobacco Amblyopia: A Clinical Manifestation of Vitamin-B12 Deficiency

Heaton, J. M.; McCormick, Ann; Freeman, A. G.

doi:10.1016/s0140-6736(58)90156-9

Cited by 111 publications

(19 citation statements)

References 20 publications

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“…Cyanide probably participates in normal metabolic processes (Boxer and Rickards, 1952) and possibly combines with B1, to form cyanocobalamin. Heaton et al (1958) reported reduced serum B1, levels in pipe smokers with visual impairment and suggested that this was related to the pathogenesis of tobacco amblyopia.…”

Section: Introductionmentioning

confidence: 99%

Effect of Vegetarianism and Smoking on Vitamin B12, Thiocyanate, and Folate Levels in the Blood of Normal Subjects

Dastur¹,

Quadros²,

Wadia³

et al. 1972

BMJ

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SummaryVitamin B,,, thiocyanate, and folate levels in the blood were estimated in 69 apparently normal subjects, of whom 26 were non-vegetarian non-smokers, 19 nonvegetarian smokers, 15 vegetarian non-smokers, and nine vegetarian smokers. The serum total (cyanideextracted) B1, level (value A) ranged from 105 to 728 pg/ml, with a mean of 292 pg/ml. The highest values were found in non-vegetarian non-smokers and the lowest in vegetarian smokers. There was no significant difference in value A between smokers as a group and non-smokers as a group. On the other hand, in vegetarians value A was very significantly lower than in non-vegetarians regardless of their smoking habits.It is suggested that A may represent both the proteinbound and free forms of vitamin B1, in the blood, and B mainly the free B12, which may be the physiologically active form. The plasma thiocyanate level varied from 1-0 to 15 Imol/100 ml, being, as expected, much higher in smokers (mean 8 20 ILmol/100 ml) than in non-smokers (mean 2-02 ,umol/100 ml). There was a rough correlation between falling B12 levels and rising thiocyanate levels. The serum folate level ranged from 2-75 to 15 75 ng/ml, and was slightly but significantly higher in vegetarians (mean 6 60 ng/ml) than in non-vegetarians (mean 4 79 ng/mi), reflecting the greater content of folate in a vegetarian diet.

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Section: Introductionmentioning

confidence: 99%

Effect of Vegetarianism and Smoking on Vitamin B12, Thiocyanate, and Folate Levels in the Blood of Normal Subjects

Dastur¹,

Quadros²,

Wadia³

et al. 1972

BMJ

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“…Thus only in these last three (Cases 9, 11, and 12) was the condition comparable to tobacco amblyopia as reported from the West, and even in these the acute onset, and the spontaneous recovery in Case 12, may raise doubts about their authenticity. We cannot, therefore, justifiably regard any of our 20 cases as being similar to the original cases of Heaton et al (1958). Heavy smoking among vegetarians in India is by no means uncommon, and hence one wonders what part smoking or a relatively low vitamin Bl2 intake has to play in this variety of amblyopia.…”

Section: Discussionmentioning

confidence: 81%

“…It was first suggested by Heaton et al in 1958 that optic neuritis in tobacco smokers was related in some way to a disturbance of vitamin B1, metabolism. In 13 patients with classical tobacco amblyopia they found the mean serum vitamin B1, value to be well below that of control subjects.…”

Section: Introductionmentioning

confidence: 99%

Role of Vegetarianism, Smoking, and Hydroxocobalamin in Optic Neuritis

Wadia¹,

Quadros²,

Dastur³

1972

BMJ

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SummaryOnly 20 patients with optic neuritis of unknown aetiology could be collected in Bombay over a period of two and a half years. Only six of them were smokers and only three (one a non-smoker) had bilateral centrocaecal scotomata similar to those found In tobacco amblyopia. In 11 untreated patients the serum vitamin B1, and plasma thiocyanate levels were estimated and found to show no significant differences from those in normal control subjects. Treatment with hydroxocobalamin in the majority of cases and with cyanocobalamin, corticotrophin, or prednisolone in the rest showed equally good results; spontaneous improvement was seen in one case.No significant role could be assigned to smoking (cyanide) or to vegetarianism in the production of optic neuritis in these patients; nor was there any evidence of depletion oftotal (cyanide-extracted) B1, or of an increase in the proportion of non-cyanide-extracted B1, in the serum.

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“…HEATON et al (9) reported that low serum B12 levels were found in heavy smoker's amblyopia. PHILLIPS et al (10,11) reported that abnormally low values of B12 in the aqueous humour and serum could be found in patients suffering from tobacco amblyopia and that they improved following treatment with B12.…”

Section: Resultsmentioning

confidence: 99%