Fluorosis in the Northern Region of Tanganyika

566 TRANSACTIONSOF THE ROYAL SOCIETYOF TROPICAL MEDICINE AND HYGIENE. Vol. 58. No. 6. November, 1964.

FLUOROSIS IN THE NORTHERN

REGION OF TANGANYIKA

BY

PAUL GRECH*

Consultant Radiologist, Ministry of Health, Dar es Salaam, Tanganyiha AND

M. C. LATHAM

Department of Nutrition, Harvard University School of Public Health, Boston, Mass. T h e high level of fluorine in some streams, the presence of dental fluorosis in man, and the effects of excessive fluorine intake in cattle, h a v e previously been noted in the Arusha District of Tanganyika (MAcQUILL~, 1944; WALKER and MILNF., 1955). T h e relation of this area to the rest of Tanganyika is shown in Map 1. In spite of this there is no record of any survey to assess the incidence of human fluorosis, nor are we aware of any published reports of human fluorosis, other than dental lesions, occurring in tropical Africa. T h e present survey was conducted on the foothills of M o u n t Meru, an extinct volcano in N o r t h e r n Region of Tanganyika. This is a preliminary report to record our findings. Work on the subject will continue. THE SURVEY

Persons were examined at four places around the base of M o u n t Meru. These were Maji ya Chai (Swahili for tea water), Oldonyo Sambu, Ngare Nanyuki and Olmotoni-Selian (Map 2). T h e fluorine content of the main source of water in these localities ranged from approximately 6 to 46 p.p.m. Notification had been made that medical examinations would be carried out at a school or courthouse on a particular day. All those who presented themselves were examined by a standardized method. T h e results were recorded on a Fluorosis Survey F o r m (Appendix 1). T h e degree of dental fluorosis and caries, the extent of nail changes, the source of the water supply and the length of time of ingestion, as well as certain personal details, were recorded on these forms. T h e results of the examination of the thyroid gland were entered on another form. All persons over 40 years of age who had lived for more than 10 years at any of the four places mentioned above were offered free X-ray examination; 775 were examined, and 112 were X-rayed. These 112 people who submitted themselves for X-ray examination were transported to Arusha Hospital for radiography; the examination included the spine, forearms, skull and chest, but not lower limbs or pelvis. * We are particularly indebted to Mr. J. Liganga, Health Inspector (Nutrition) for his help in this survey; to Mr. G. W. Walker, Government Chemist, for the fluorine estimations and for his valuable advice; to Dr. Howard Middlemiss, Director of Radiology, Bristol, for his encouragement; and to Dr. J. Hamerton, Clinical Photography Section, for some of the photographic reproductions. We acknowledge with gratitude the grant from E. A. Medical Research Council for the purchase of X-ray films. Finally, we wish to thank Dr. W. J. Maelor Evans, Chief Medical Officer, Tanganyika, for his permission to publish this paper and for his help in carrying out this survey.

P A U L GRECH A N D M . - C . L A T H A M

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MAP 1.

TABLE I.

Fluorine content of waters (WALKERand MILNE, 1955). the places in Map 2).

Map No.

Area

(Figures in first column locate

Fluorine p.p.m.

1

Maji ya Chai river

18.6

2

Oldonyo Sambu

(a) pipeline (b) spring

14.3 14.4

3

Ngare Nanyuki

(a) river (b) tributary

24.0* 45.5*

4

Olmotoni-Selian

(a) Olmotoniriver (b) Selian river

5.9 6.4

* This water, though used for cooking and domestic purposes, is not drunk regularly. People in this area get their drinking water from a nearby spring. A sample of this source has been analysed and shows a fluorine content of 6 p.p.m.

568

FLUOROSIS I N THE NORTHERN REGION OF TANGANYIKA \

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.

MAP 2.

RESULTS

(a) Fluorosis of teeth The degree of dental fluorosis was recorded by using a modification of the classification suggested by DEAN (1938). This classification, which divides fluorotie teeth into six categories, was simplified as follows: 0 - - N o fluorosis 1--Mild 2--Moderate ,, 3--Severe ,, The results of the examinations are shown in Table II.

PAUL GRECHAND M. C. LATHAM TABLE II.

569

Teeth--fluorosis and caries. i

Fluorosis

No.

Caries

of

arnined

1

2

3

persons with markedly worn teeth

1. Maji ya Chai (a) Non-school

188

8

28

150

62

(b) School

192

2

30

160

22

2

2. Oldonyo Sambu

30

8

8

9

21

15

3. Ngare Nanyuki (a) Non-school

111

17

10

10

74

33

50

68

(b) School

133

23

9

13

88

24

3

11

6

4

107

50

281

122

43

93

588

183

620

342

]

No.

l

ex-

4. Olmotoni-Selian

121

Totals

775

Grades of mottling

3* 50

]-

No. of DMF

No. missing for tribal reasons

243

124

teeth

* I edentulous (not included). It can be seen that a very high incidence of dental fluorosis exists. This took the form mainly of brown pigmented patches most obvious on the incisors, both upper and lower, but it was very often present on all teeth; these areas were frequently roughened, and sometimes pitted. White chalky patches were observed in some subjects. T h e teeth in many persons were markedly worn down, and very severe wearing was recorded in 23.6 per cent. of those examined (Fig. 1). (b) Dental caries T h e figure recorded indicated the n u m b e r of teeth decayed, missing or filled ( D M F ) . In most instances the teeth were examined in direct light. T h e only instruments used were a dental mirror and a probe, and sometimes a flashlight. T h e total in the table is therefore rather conservative, because small or hidden cavities must frequently be missed in a cursory examination of this kind. T e e t h removed in childhood as a tribal custom are recorded separately, as they do not reflect the incidence of caries (Table II, last column). T h e n u m b e r of teeth filled was very small. Gingivitis and other forms of oral sepsis were very common. (c) Nails Various reports have stated that changes and deformities in the nails occur in fluorosis. SPIRA (1943) described these changes as an early sign of fluorosis. In all persons seen, the nails of both hands were examined. T h e degree of mottling was classified as follows: 0--Nil. 1--Mild. 2--Marked. Mottling referred to irregularities including striation, abnormal shape, pitting and other changes; this was only recorded if present in more than three nails. It is believed that this would avoid the inclusion of nails deformed by injury. Nails which were markedly striated or spoon-shaped were also recorded (Table III).

570

FLUOROSIS IN THE NORTHERN REGION~OF TANGANYIKA

TABLE III.

Nails.

Degree of mottling

No. of per- No. of persons with sons with striated spoonnails shaped nails

No.

examined

1 c

1. Maji ya Chai (a) Non-School

188

102

84

2

49

16

(b) School

192

142

49

1

22

6

2. Oldonyo Sambu

30

17

13

0

9

4

3. Ngare Nanyuki (a) Non-School

111

69

41

32

(b) School

133

98

35

27

4. Olmotoni-Selian

121

50

71

53

23

Totals

775

478 '

293

192

59

(d) Goitre T h e goitre incidence was recorded, firstly because goitre has been related to fluorosis (GALLETI and JOYE% 1958) and secondly because the incidence of goitre in Tanganyika is currently being studied as a separate project. T h e thyroid gland of each individual was examined both visually and by palpation. T h e size of this gland was classified on W H O Classification ( " E n d e m i c Goitre," W H O , 1960). T h e findings are shown in T a b l e IV. T h i s shows an incidence of 22.8 per cent. of those examined. Only 11 persons had adenomatous glands. TABLE IV.

Goitre.

Size of thyroid

No.

No.

Locale

3

adenomatous

examined

0

1

2

1. Maji ya Chai (a) Non-school

188

144

29

14

1

5

(b) School

192

137

53

2

0

0

2. Oldonyo Sambu

30

20

8

2

0

0

3. Ngare Nanyuki (a) Non-school

111

85

19

(b) School

133

117

16

4. Olmotoni-Selian

121

95

19

7

0

2

Totals

775

598

144

32

1

11

0

PAUL GRECH AND M . C. L A T H A M

571

(e) Radiological findings 87 per cent. of the 112 persons examined radiologically showed bony changes believed to be due to fluorine poisoning; 19 per cent. showed marked changes. The main radiological findings noted in this series were: (i) Increased density of bone. ~This was the most frequent finding, being present in 82 per cent. of spines, 74 per cent. of forearms, and in 30 per cent. of skulls. The trabeculation first becomes coarse, and usually on top of this a gradually increasing chalky density supervenes which obliterates the bony architecture. This is due to increased osteoblastic activity which gives rise to the new dense bone. It starts under the periosteum and extends into the cortex and also involves points of attachment of muscles and ligaments. As a result the diameter of the bone is increased, the cortex is thickened, and the medullary cavity may be encroached upon and therefore reduced. The bone appears bulkier. These changes were best seen in the spine, but any bone that was X-rayed could be involved, even the mandible.

Fla. 1. Severe dental fluorosis in a girl of 19 years. (ii) Marginal lipping of the vertebral bodies was present in 45 per cent. of the cases, most commonly in the lumbar segment. These are usually associated with: (iii) Calcification of ligaments and muscular attachments, best seen along the spine. Calcification of the paravertebral ligaments was present in 20 per cent. of this series. In three cases there was complete rigidity of the whole spine. Calcareous deposits along the interosseous margins of the radius and ulna can be most spectacular, showing a serrated edge, most marked along the middle third (Fig. 2). This was associated with marked thickening and increased density of the bones; the distal ends of both bones were unaffected and normal bone trabeculation could be seen there. This is most probably due to the fact that these parts are more or less free from muscular insertions, except for the pronator quadratus on the anterior aspect.

FIG. 2. X-ray of forearms of a 4%year-old inhabitant of Olomotoni where the local water has 6.4 parts per million of fluorine. Note the calcareous deposits along the interosseous membrane, most marked along the middle third.

(To face page 570)

572

F L U O R O S I S IN T H E N O R T H E R N

REGION OF TANGANYIKA

Another common site of calcification was the insertion of the triceps tendon on the olecranon process (26 per cent.). (iv) Trabeculation. Sometimes these calcified ligamentous and muscular insertions show trabeculation, indicating that ossification has taken place. This abnormal ossification has been noted in the triceps insertion and in the paravertebral ligaments. No abnormal calcification was noted in the brain substance; the only calcification seen within the skull was that of the clinoid ligaments, usually involving the clinoid processes which became thicker and denser. No vascular calcification was observed; this could be due to the fact that the lower limbs were not X-rayed. The fracture rate appeared to be unaffected; in all the bones X-rayed, only three old united fractures were observed. (f) Clinical findings Only a cursory clinical examination was carried out. 71 per cent. of those X-rayed complained of pain in their bones, the most common sites being the back, chest and legs in that order. Backache was found to be relative to the degree of spondylitis. DISCUSSION

This survey was carried out in the Northern Region of Tanganyika where the fluorine content of rivers and springs was known to be abnormally high. The very high rate of severe mottling confirms what would be expected in areas where the water fluorine content was so high. The marked wearing down of the teeth and the unsightly brown pigmentation were prominent features. The incidence of dental caries is low by most standards (DauMMOND and WIrBaaaaM, 1935). However, no figures are available of caries incidence among people of the same ethnic origin and on the same diet with a lower fluorine intake than the subjects in this series. The nail changes could be a feature of fluorine poisoning, though not a reliable finding. A control group of persons examined on the coast of Tanganyika, drinking water with a fluorine content of 0.2 p.p.m., Showed nail changes in only 9 per cent. as opposed to 37.1 per cent. in the Meru group. It is difficult to explain why only just over one third of the subjects in the group had nail changes when 93.4 per cent. had mottled teeth and 87 per cent. of those X-rayed showed bony changes. The incidence of goitre was 22.8 per cent., which does not appear to be of any special significance on this subject in this area. The main object of the survey was to confirm the existence of human fluorosis in the area. A fairly static population inhabits these plans, and of those examined only a "selected" group were X-rayed. SHOaTTet al. (1937) suggested a probable cumulative effect of fluorine which continues until the subject is 30 or 40 years old. On this assumption our sample consisted of subjects over 40 years of age. The persons X-rayed were all over 40, having lived in the area and consumed the "local" water for 10 years or more; about half were between 40 and 50 years old. This accounts for the high incidence of positive radiological findings; it also accounts for absence of osteoporosis which occasionally occurs in fluorine poisoning in the younger and early stages (MIDDLEMISS, 1961). Increased bone density seen in the bones X-rayed followed the same pattern as that described by ROHOLM (1937) and subsequent authors. Skull changes followed the same lines as observed by SIDDIQUI (1955). The increased density was usually associated with

FIG. 3. Skull of an inhabitant of Oldonyo Sambu, where the local water has a fluorine content of 14.3 parts per million, showing encroachment on the air cells, increased density at the base of the skull and calcification of the clinoid ligaments.

PAUL GRECH AND M. C. LATHAM

573

thickening of the skull, and the radiological demarcation of the diploe and the inner and outer tables was usually lost. Both vault and base were affected, and the air cells were frequently narrowed (Fig. 3). It was also noted that the frontal sinus was absent in 21 per cent. of this series. It has been made clear that this is a report of a preliminary investigation. It indicates that fluorine poisoning is endemic in the Meru area and that bone changes, previously unrecorded in this part of Africa, are very common in this area. Work on the subject will continue. It will include an attempt to ascertain at what level of fluorine intake certain bone changes occur; at what age these become visible radiologically at the different levels of fluorine intake; and what clinical effects these pathological changes have on the patients. It is also hoped to ascertain the fluorine content of the bones of some affected persons. SUMMARY

A survey has been carried out in the Northern Region of Tanganyika where the fluorine content of some water sources is known to be abnormally high. 775 persons were examined, and 112 of these X-rayed. Those X-rayed were 40 years of age or over and had drunk water with high fluorine content for 10 years or more. Details are given of findings related to teeth, nails and thyroid gland. Dental fluorosis was found in 93.4 per cent. but the incidence of dental caries was comparatively low. Nail changes were found in 37.1 per cent. and goitre in 22.8 per cent. 87 per cent. of those X-rayed presented bony changes, some severe. The various radiological findings are described. REFERENCES

DEAN,H. T. (1938). Amer. Ass. Advancement of Science, p. 23. DRUMMOND, J. C. & WILBRAHAM,A. (1935). Lancet, 2, 459. GALLETI,P. M. & JOYET, G. (1958). J. clin. Endocrin., 18, 1102. MAcQUILLAN,C. J. (1944). E. Afr. med. J., 21, 131. MIDDLEMISS,H. (1961). Tropical Radiology, VII, 68. London: William Heinemann. ROHOLM,K. (1937). Fluorine Intoxication. London: H. K. Lewis. SHORTT, H. E., McRoB~.RT, G. R., BARNARD,T. W. & NAYAR,A. S. N. (1937). Indian J. med. Res., 25, 553. SIDDIQUI,A. n. (1955). Brit. med. J., 2, 1412. SPmA, L. (1943)..7. Hyg., 43, 69. WALKER,G. W. & MILNE, A . H . E. Aft. agr. J., 21, 1.

574

FLUOROSIS IN THE NORTHERN REGION OF TANGANYIKA

APPENDIX I.

Nutrition Unit, M i n i s t r y of H e a l t h , P.O. Box 9083, D a r e s Salaam.

Fluorosis Survey Form District

......................................................

Institution ...................................................

A r e a or Village . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Date

...................................................

Examiner ......................................................

A

B

C

D

E

No.

Name

Sex

Age

Dental Fluorosis

Dent. Car.

G

H

I

J

K

Nails Mottled

Source of water

Time at H

X-ray

Remarks including features possibly related to Bone Fluorosis

No. DMF

(1)

MF

0123

012

(2)

MF

0123

012

NOS.