791 TABLE I-PREVALENCE OF VARICOSE VEINS IN
1259 TANZANIANS
Wider World VARICOSE VEINS IN TROPICAL AFRICA
J. B. RICHARDSON Aberdeen University Medical School MICHAEL DIXON
Guy’s Medical School,
London
1259 Tanzanians in a provincial town examined for varicose veins. 5·5% of men and 5·0% of women) of the 1000 people (6·1% aged eighteen years and over had varicose veins. This prevalence is intermediate between that reported for minimally developed areas (0·1%-0·4%) and the ageadjusted rate reported for Michigan (12·3%). The Tanzanian diet included some refined carbohydrate, and the mean daily stool weight (228 g) indicated a fibre content intermediate between that of traditional African communities (490 g) and western countries (115 g). These findings are consistent with the hypothesis relating varicosities to a fibre-depleted diet. Life-long use of the squatting position for defæcation did not protect against the development of varicose veins.
Summary
were
INTRODUCTION
THE pronounced geographical variation in the prevalence of varicose veins implies that an environmental factor is involved in their development in western countries.’The prevalence of varicose veins is reported to be low in tropical Africa;l-5 however, although much information has been collected in Africa on the basis of observed cases among hospital attenders, few specific surveys have been performed.6 During an elective period at Moshi, Tanzania, we investigated the prevalence of varicose veins and evaluated possible risk factors in the
was due entirely to the greater ages of the men. The prevalence of varicose veins in the women in relation to their age and number of children is shown in table n. There was no correlation between age and prevalence of varicose veins or between number of children and prevalence of varicose veins. However, the numbers were too small for significant differences to become apparent. 4.4% of civil servants and their families (119 examined) had varicose veins. This does not
preponderance
TABLE II-PREVALENCE OF VARICOSE VEINS IN WOMEN IN RELATION TO THEIR AGE OR NUMBER OF CHILDREN
population. METHOD at the outin northern Tanzania. These people attended with various mild illnesses unrelated to varicose veins and are assumed to be representative of the population of the area. The few people of Asian origin who attended were not included since their cultural background differed from that of the Africans. In this survey veins were described as varicose if they were visibly dilated and tortuous. Possible risk factors recorded for all subjects included age, sex, number of children (in women only), and socioeconomic group. 157 consecutive subjects were asked what posture they adopted for defecation. 100 people were asked to list all items eaten the previous day. In 5 cases the daily stool weight was measured over four days to give a measure of dietary-fibre intake.2
1259 Tanzanians of all ages
patient clinics in Moshi,
a
were
provincial
examined
town
RESULTS
A 1000 of the 1259 subjects examined were aged eighteen years and over (adults), and 5-3% of them had vaÙose veins (6-1% of 456 men examined and 5.0% of
544
examined). None of the 256 aged less than had varicose veins (table I). The slight male
women
eighteen
differ
significantly from the prevalence population (age-adjusted).
in the
general
6-3% of those asked had at some time (mean duration of use 4 years) used a pedestal water-closet (w.c.). 20 of the 87 civil servants asked had used a w.c., compared with only 3 out of the 70 from the general population (=9.5, P=001). All but 1 of the 32 subjects with varicose veins who were asked had always squatted to defaecate.
The staple diet was maize and meat, supplemented with white rice, bananas, and fish. A third of the maize eaten was refined and sugar was commonly eaten. Some subjects ate white bread. Then mean daily stool weight was 228 g (range 125-300 g). Only 17 cases had been admitted to the area hospital over the period 1973-75 (during which there had been 46 775 admissions) for treatment of varicose veins, with a male preponderance of 4/1. Many diseases typical of western countries were rare. The case-rates per 10 000 admissions were: diabetes 65; appendicitis 48; intestinal
792
carcinoma 7; myocardial infarction 2. A radiological survey of 1206 people found hiatus hernia in only 2.7 DISCUSSION
The very small number of cases of varicose veins presenting to the area hospital did not reflect either our findings among 1259 outpatients, or the equal distribution between the sexes. This illustrates the limitations of
hospital-based’ epidemiological
surveys of a comparamild disease and would explain why specific surveys have not found a prevalence as low as that reported by surgeons practising in tropical Africa.6 The prevalence of varicose veins in five surveys in tropical Africa ranged from 0.12% in 5000 Ugandan adults only slightly influenced by western culture2 to 7-7% in 297 adult women in the Transkei,5 where the western influence is stronger. A prevalence of 10-9% was reported in 469 women in Mali,4 but this survey included cases of intradermal venectasia in the definition of varicose veins. Varicose veins are significantly more common in west9 Results must be age adjusted to ern populations.8 exclude the possibility that the high prevalence in western countries merely reflects the greater proportion of old people. In a total population survey near Michigan, U.S.A., in which criteria apparently similar to our own were used, the prevalence of varicose veins was 19-8%." After age-adjustment to the population seen at Moshi, this falls to 12.3%; however, this is significantly greater than the prevalence of 4.5% observed at Moshi in those over 10 years of age (=10-8, men; x,2=51.9, women;
tively
p=0.001). Pregnancy
may have contributed to the development of varicose veins in the population we studied, but cannot be a principal cause since the prevalence of varicose veins was equal in both men and women. Westernisation brings innumerable changes in lifestyle and environment. Such changes were especially pronounced in the civil servants and included factors implicated in the causation of varices-i.e., using a pedestal w.c., leading a more sedentary life," and, to obtain academic qualifications, spending more time sitting down during childhood. 11 12 Varicose veins were not significantly more common in the civil servants than in the others in the survey nor did their diet differ significantly. These results do not exclude a dietary factor in the aetiology of varicose veins. The life-long use of the squatting position during defsecation did not apparently protect against the development of varicose veins. This accords with the report that squatting does not protect the superficial leg veins from increases in intra-abdominal pressures when straining at stool. 13 A diet deficient in fibre has been implicated as a major factor in the causation of varicose veins.2 14 There is evidence that a fibre-depleted diet leads to constipation and that subsequent straining at stool produces high intraabdominal pressures which are transmitted to the leg veins and progressively dilate them.6 The traditional diet in Moshi has been considerably modified. Both the degree of refinement of the diet and mean daily stool weights are intermediate between those of rural Africans and western populations. Thus our finding that the prevalence of varicose veins in the Moshi population was intermediate between that of rural Africans and western countries is consistent with
Mean daily stool weights and prevalence of varicose veins in communities eating different diets (15 Ugandan villagers,’ 6389 North Americans," and 30 North Americans"). *Prevalence in North America is age and zanian population.
sex
adjusted
to
the Tan-
the dietary hypothesis (see accompanying figure). The apparent rarity of other "western" diseases which may be related to a refined diet14 15 does not parallel the moderate prevalence of varicose veins in the Tanzanian population. If these diseases-e.g., diabetes, appendicitis, intestinal carcinoma, ischsemic heart-disease, hiatus hernia-and varicose veins have a common xtiology, it must be assumed that varicose veins are the first of these diseases to emerge in this population. We thank the people of Moshi for their cooperation, Miss D. Forfor statistical advice, and Mr D. P. Burkitt for his help and en-
dyce
couragement.
Requests for reprints should be addressed to versity Medical School, Foresterhill, Aberdeen.
J.B.R. Aberdeen Uni-
REFERENCES A. M., Salmond, C., Davidson, F. Int. J. Epidem. 1975, 4, 295. 2. Burkitt, D. P. Br. med. J. 1972, ii, 556. 3. Worsfold, J. T. Lancet, 1974, ii, 1322. 4. Rougemont, A. ibid. 1974, i, 870. 5 Daynes, G., Beighton, P. Br. med. J. 1973, iii, 354. 6. Burkitt, D. P. Archs. Surg. 1976, 111, 1327. 7. Burkitt, D. P., James, P. A. Lancet, 1973, ii, 128. 8. Coon, W. W., Park, W. W., Keller, J. B. Circulation, 1973, 158, 839. 9. Silva, A. da, Widmer, L. K., Martin, H., Mall, Th., Glaus, L., Schneider, M. Vasa, 1974, 3, 118. 10. Rivlin, S. Lancet, 1974, i, 1054. 11. Alexander, C. J. ibid. 1972, i, 822. 12. Stanhope, J. M. Int. J. Epidem. 1975, 4, 221. 13. Martin, A., Odling-Smee, W. Lancet, 1976, i, 768. 14. Cleave, T. L., Campbell, G. C., Painter, N. S. Diabetes, Coronary Thrombosis and the Saccharine Disease. Bristol, 1969. 15. Burkitt, D. P., Trowell, H. C. (editors) Refined Carbohydrate Foods and Disease; p. 338, New York, 1975. 16. Wozasek, O. Am. J. dig. Dis. 1942, 9, 423. 1.
Beaglehole, R., Prior,
"I am not at all certain what correspondence columns are for: we all enjoy reading them; they presumably act as a forum for debate, but unfortunately the exchanges can become acrimonious or merely posturing. Perhaps we have only ourselves to blame for not making the standard high enough and especially for our failure to examine why we write and how, as authors, we reply. James Learmonth made it easy for himself and his staff by insisting that the only two reasons for writing to a journal were to promote a charity or to defend a colleague; but this was literary Calvinism."—HUGH DUDLEY in The Presentation of Original Work in Medicine and Biology; p. 29. Edinburgh: Churchill Livingstone.
1259 TANZANIANS
Wider World VARICOSE VEINS IN TROPICAL AFRICA
J. B. RICHARDSON Aberdeen University Medical School MICHAEL DIXON
Guy’s Medical School,
London
1259 Tanzanians in a provincial town examined for varicose veins. 5·5% of men and 5·0% of women) of the 1000 people (6·1% aged eighteen years and over had varicose veins. This prevalence is intermediate between that reported for minimally developed areas (0·1%-0·4%) and the ageadjusted rate reported for Michigan (12·3%). The Tanzanian diet included some refined carbohydrate, and the mean daily stool weight (228 g) indicated a fibre content intermediate between that of traditional African communities (490 g) and western countries (115 g). These findings are consistent with the hypothesis relating varicosities to a fibre-depleted diet. Life-long use of the squatting position for defæcation did not protect against the development of varicose veins.
Summary
were
INTRODUCTION
THE pronounced geographical variation in the prevalence of varicose veins implies that an environmental factor is involved in their development in western countries.’The prevalence of varicose veins is reported to be low in tropical Africa;l-5 however, although much information has been collected in Africa on the basis of observed cases among hospital attenders, few specific surveys have been performed.6 During an elective period at Moshi, Tanzania, we investigated the prevalence of varicose veins and evaluated possible risk factors in the
was due entirely to the greater ages of the men. The prevalence of varicose veins in the women in relation to their age and number of children is shown in table n. There was no correlation between age and prevalence of varicose veins or between number of children and prevalence of varicose veins. However, the numbers were too small for significant differences to become apparent. 4.4% of civil servants and their families (119 examined) had varicose veins. This does not
preponderance
TABLE II-PREVALENCE OF VARICOSE VEINS IN WOMEN IN RELATION TO THEIR AGE OR NUMBER OF CHILDREN
population. METHOD at the outin northern Tanzania. These people attended with various mild illnesses unrelated to varicose veins and are assumed to be representative of the population of the area. The few people of Asian origin who attended were not included since their cultural background differed from that of the Africans. In this survey veins were described as varicose if they were visibly dilated and tortuous. Possible risk factors recorded for all subjects included age, sex, number of children (in women only), and socioeconomic group. 157 consecutive subjects were asked what posture they adopted for defecation. 100 people were asked to list all items eaten the previous day. In 5 cases the daily stool weight was measured over four days to give a measure of dietary-fibre intake.2
1259 Tanzanians of all ages
patient clinics in Moshi,
a
were
provincial
examined
town
RESULTS
A 1000 of the 1259 subjects examined were aged eighteen years and over (adults), and 5-3% of them had vaÙose veins (6-1% of 456 men examined and 5.0% of
544
examined). None of the 256 aged less than had varicose veins (table I). The slight male
women
eighteen
differ
significantly from the prevalence population (age-adjusted).
in the
general
6-3% of those asked had at some time (mean duration of use 4 years) used a pedestal water-closet (w.c.). 20 of the 87 civil servants asked had used a w.c., compared with only 3 out of the 70 from the general population (=9.5, P=001). All but 1 of the 32 subjects with varicose veins who were asked had always squatted to defaecate.
The staple diet was maize and meat, supplemented with white rice, bananas, and fish. A third of the maize eaten was refined and sugar was commonly eaten. Some subjects ate white bread. Then mean daily stool weight was 228 g (range 125-300 g). Only 17 cases had been admitted to the area hospital over the period 1973-75 (during which there had been 46 775 admissions) for treatment of varicose veins, with a male preponderance of 4/1. Many diseases typical of western countries were rare. The case-rates per 10 000 admissions were: diabetes 65; appendicitis 48; intestinal
792
carcinoma 7; myocardial infarction 2. A radiological survey of 1206 people found hiatus hernia in only 2.7 DISCUSSION
The very small number of cases of varicose veins presenting to the area hospital did not reflect either our findings among 1259 outpatients, or the equal distribution between the sexes. This illustrates the limitations of
hospital-based’ epidemiological
surveys of a comparamild disease and would explain why specific surveys have not found a prevalence as low as that reported by surgeons practising in tropical Africa.6 The prevalence of varicose veins in five surveys in tropical Africa ranged from 0.12% in 5000 Ugandan adults only slightly influenced by western culture2 to 7-7% in 297 adult women in the Transkei,5 where the western influence is stronger. A prevalence of 10-9% was reported in 469 women in Mali,4 but this survey included cases of intradermal venectasia in the definition of varicose veins. Varicose veins are significantly more common in west9 Results must be age adjusted to ern populations.8 exclude the possibility that the high prevalence in western countries merely reflects the greater proportion of old people. In a total population survey near Michigan, U.S.A., in which criteria apparently similar to our own were used, the prevalence of varicose veins was 19-8%." After age-adjustment to the population seen at Moshi, this falls to 12.3%; however, this is significantly greater than the prevalence of 4.5% observed at Moshi in those over 10 years of age (=10-8, men; x,2=51.9, women;
tively
p=0.001). Pregnancy
may have contributed to the development of varicose veins in the population we studied, but cannot be a principal cause since the prevalence of varicose veins was equal in both men and women. Westernisation brings innumerable changes in lifestyle and environment. Such changes were especially pronounced in the civil servants and included factors implicated in the causation of varices-i.e., using a pedestal w.c., leading a more sedentary life," and, to obtain academic qualifications, spending more time sitting down during childhood. 11 12 Varicose veins were not significantly more common in the civil servants than in the others in the survey nor did their diet differ significantly. These results do not exclude a dietary factor in the aetiology of varicose veins. The life-long use of the squatting position during defsecation did not apparently protect against the development of varicose veins. This accords with the report that squatting does not protect the superficial leg veins from increases in intra-abdominal pressures when straining at stool. 13 A diet deficient in fibre has been implicated as a major factor in the causation of varicose veins.2 14 There is evidence that a fibre-depleted diet leads to constipation and that subsequent straining at stool produces high intraabdominal pressures which are transmitted to the leg veins and progressively dilate them.6 The traditional diet in Moshi has been considerably modified. Both the degree of refinement of the diet and mean daily stool weights are intermediate between those of rural Africans and western populations. Thus our finding that the prevalence of varicose veins in the Moshi population was intermediate between that of rural Africans and western countries is consistent with
Mean daily stool weights and prevalence of varicose veins in communities eating different diets (15 Ugandan villagers,’ 6389 North Americans," and 30 North Americans"). *Prevalence in North America is age and zanian population.
sex
adjusted
to
the Tan-
the dietary hypothesis (see accompanying figure). The apparent rarity of other "western" diseases which may be related to a refined diet14 15 does not parallel the moderate prevalence of varicose veins in the Tanzanian population. If these diseases-e.g., diabetes, appendicitis, intestinal carcinoma, ischsemic heart-disease, hiatus hernia-and varicose veins have a common xtiology, it must be assumed that varicose veins are the first of these diseases to emerge in this population. We thank the people of Moshi for their cooperation, Miss D. Forfor statistical advice, and Mr D. P. Burkitt for his help and en-
dyce
couragement.
Requests for reprints should be addressed to versity Medical School, Foresterhill, Aberdeen.
J.B.R. Aberdeen Uni-
REFERENCES A. M., Salmond, C., Davidson, F. Int. J. Epidem. 1975, 4, 295. 2. Burkitt, D. P. Br. med. J. 1972, ii, 556. 3. Worsfold, J. T. Lancet, 1974, ii, 1322. 4. Rougemont, A. ibid. 1974, i, 870. 5 Daynes, G., Beighton, P. Br. med. J. 1973, iii, 354. 6. Burkitt, D. P. Archs. Surg. 1976, 111, 1327. 7. Burkitt, D. P., James, P. A. Lancet, 1973, ii, 128. 8. Coon, W. W., Park, W. W., Keller, J. B. Circulation, 1973, 158, 839. 9. Silva, A. da, Widmer, L. K., Martin, H., Mall, Th., Glaus, L., Schneider, M. Vasa, 1974, 3, 118. 10. Rivlin, S. Lancet, 1974, i, 1054. 11. Alexander, C. J. ibid. 1972, i, 822. 12. Stanhope, J. M. Int. J. Epidem. 1975, 4, 221. 13. Martin, A., Odling-Smee, W. Lancet, 1976, i, 768. 14. Cleave, T. L., Campbell, G. C., Painter, N. S. Diabetes, Coronary Thrombosis and the Saccharine Disease. Bristol, 1969. 15. Burkitt, D. P., Trowell, H. C. (editors) Refined Carbohydrate Foods and Disease; p. 338, New York, 1975. 16. Wozasek, O. Am. J. dig. Dis. 1942, 9, 423. 1.
Beaglehole, R., Prior,
"I am not at all certain what correspondence columns are for: we all enjoy reading them; they presumably act as a forum for debate, but unfortunately the exchanges can become acrimonious or merely posturing. Perhaps we have only ourselves to blame for not making the standard high enough and especially for our failure to examine why we write and how, as authors, we reply. James Learmonth made it easy for himself and his staff by insisting that the only two reasons for writing to a journal were to promote a charity or to defend a colleague; but this was literary Calvinism."—HUGH DUDLEY in The Presentation of Original Work in Medicine and Biology; p. 29. Edinburgh: Churchill Livingstone.
