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Biomedical Research

Study of the effects of drinking water naturally contaminated with fluorides on the health of children

Author(s): Kumar T and Takalkar A

Vol. 21, No. 4 (2010-10 - 2010-12)

Kumar T1 and Takalkar A2

(1) Department of Physiology, Teerthanker Mahaveer Medical College & research Center, Moradabad – 244001, U.P.
(2) Department of Community medicine, Kamineni Institute of Medical sciences, Narketpally – 508254, A.P.


Excess of fluorides in drinking water or food causes fluorosis. It affects most of the tissues of human body and is incurable but it can be prevented if it is diagnosed in early stages. The onset of fluorosis can be delayed and its severity is minimized by consumption of food rich in calcium and vitamin D. A useful technique has been recently developed in India, the SA/GAG (Sialic acid/ Glycosaminoglycans) test for early detection of the disease. Fluorosis is diagnosed in late stage by radiographs of bones and joints. Besides these methods a home based approach has been also developed for early detection of the disease which consists of some physical tests, gastrointestinal complaints and general manifestations. It is very useful in rural areas. The following study shows the role of fluorides in the crippling disease of school children at Narketpally village in Nalgonda district of Andhra Pradesh.

Key words: Fluorosis, physical tests, Sialic acid, Glycosaminoglycans test
Accepted March 9 2010


Fluoride is the thirteenth most common element in the earth’s crust. It is well known fact that fluoride helps pre-vent and even reverse the early stages of tooth decay but exposure to excess of fluoride can cause dental fluorosis and weakening of bones and pain especially in neck, back, shoulder and knee joint. It can cause various non-skeletal manifestations including gastrointestinal complaints like nausea, vomiting, diarrhea and abdominal pain. It has been documented that it can suppress immunity and lower IQ in children after long term exposure. Thus fluoride is just like a double edge sword.

The toxic effect of chronic fluoride consumption was first reported by Short in 1937[1] from southern state of India. The WHO has recommended safety level for fluoride in water. It is 0.7 to 1.2ppm (parts per millions). The US National Academy has published that fluoride inhibits various enzymes above level of 1.00ppm. The latest stan-dard issued by Bureau of Indian Standard (BIS) for fluoride in drinking water is 1.00 ppm. A useful technique was developed by Susheela, Das and Khurana in 1988 for detection of cases of fluorosis. The test was based on cir-culating level of sialic acid and glycosaminoglycans (SA/GAG test) [2].

It has been found that fluoride toxicity is minimized with consumption of foods that are rich in calcium and vitamin D like chestnuts, calms, dark green leafy vegetables, mo-lasses, oats, soybeans and wheat germs etc.

The objective of this study was to recognize the effects and extent of fluoride toxicity amongst school children of Narketpally village and to make the people realize the significance of defluorinated water so that better preven-tive measures can be taken for the children to make their life normal as far as possible.

Materials and Methods

Study design

A cross–sectional analytical study was conducted on the school children of 5 – 10 years.

Study population

The cases were taken from ‘Little flower school’ at Narketpally village in Nalgonda district of Andhra Pradesh and controls were taken for comparison from a convent at Secunderabad, “Gandhian public school”.


The cases were permanent residents of Narketpally in Nalgonda district which is a high fluoride zone. They were children of 5 – 10 years age group. The controls were the children of same age group, free from the fluoride toxicity and drinking safe water containing normal fluoride level.

Sampling technique

The children were divided into five age groups to study the progressive toxic effects of fluoride in different age groups. The five subgroups were 5-6, 6-7, 7-8, 8-9 and 9-10 years. Twenty students were selected from each age group.

Ethical clearance and informed consent

Ethical clearance was obtained from the ethical committee of Kamineni Institute of Medical Sciences, Narket-pally and official permission was received from the principal and director of the school.

Collection and analysis of water samples

Five water samples were collected from the water bottles of the children and the tube well available in the school campus. The fluoride content was tested in all water samples with “Ion selective electrode method” [3] and the observations were recorded.


The study was done from 1st Feb 2008 to 31st January 2009.

Study tools

The first part consisted of questionnaire regarding demographic data, permanent address, source of drinking water, duration of the use of water, staple food and liquids routinely consumed (Nanda, 1973) [4] and aids used for oral hygiene maintenance.

In second part, cases were examined clinically for dental fluorosis, skeletal manifestations and gastrointestinal abnormalities. Teeth of the children were examined for mottling, cracks and pitting in teeth.

Physical tests for skeletal fluorosis

Figure 1. Showing Physical tests for skeletal fluorosis
Left column– Normal person
Right column – Fluorosis diseased

For examination of skeletal manifestations some physical tests were done to assess aches and pains in different joints of the body. The physical tests were the basic exer-cises related to body posture as shown above [5].

A diseased person with fluorosis is unable to bend completely without folding knees (Top), unable to bend the neck to touch the chin on the chest (Middle) and unable to bend arms to touch the back of the head (bottom).

For gastrointestinal manifestations, all cases were evaluated clinically for dyspeptic symptoms like nausea, vomiting and upper abdominal pain [6].

The third part consisted of investigations. Radiological examination of all cases was done to assess the involve-ment of bones and joints [7].

The stool tests were done for cysts and ova to rule out parasitic infections. All cases underwent upper gastroin-testinal endoscopy using fiber-optic endoscope in order to rule out gastrointestinal manifestations due to chronic exposure to fluoride containing water [8]. Abdominal sonography was done to rule out inflammation or any growth in gall bladder, liver, portal vein, spleen or pancreas.

After clinical examinations and investigations of the cases, the children were provided defluorinated water for one month and then re – examined to see the response.


Observations of the tests of water have been shown in table 1 which showed the high fluoride content in all wa-ter samples collected from the children and the tube well of the school campus.

The table 2 shows the number and percentage of cases from different age groups afflicted with dental fluorosis, skeletal fluorosis, gastrointestinal manifestations and other non – skeletal manifestations like muscle weakness, anemia and inability to carry out routine works. Assess-ment of anemia was done by clinical examination of mucous membrane, conjunctiva and skin (pallor).

Most of the cases from different age groups were afflicted with dental fluorosis but the severity was more in highest amongst elder children showing cracks and pitting with brown pigmentation in teeth. Five cases from 9-10 years age group were afflicted with skeletal fluorosis. They had pains and aches in bones and different joints. The prevalence of skeletal fluorosis was zero in younger children.

The gastrointestinal dyspeptic symptoms like nausea vo-miting and abdominal pain were most common (25%) in children of lower age group and least common (16.7%) in higher age group. Non – skeletal manifestations like mus-cle weakness and inability to carry out routine works were also more prevalent amongst higher age group children.

The table 3 shows the observations of different investiga-tions. Four cases were found to have the ova of Ascaris lumbricoides, two case from 5-6 year age group and one case each from 6-7 and 7-8 years age group. Others in-cluding controls were normal.

Radiological examination of the cases revealed positive changes in 10 cases. 8 amongst them belonged to 9–10 years and 2 were from 8-9 years age group. They had radiological features such as generalized increase in bone density and calcification of interosseous membrane. Ra-diographs of control group were normal. The upper gas-trointestinal endoscopy revealed diffuse erythema and petechiae amongst 36 cases. Remaining cases and con-trols were normal. The abdominal sonography was nor-mal. There was neither inflammation nor any growth found in liver, gall bladder or kidney in any of the sub-jects or controls.

When the children were supplied safe drinking water for one month, the gastrointestinal manifestations almost dis-appeared and the severity of non – skeletal manifestations including gastrointestinal manifestations was also de-creased.

Table 1: Table showing fluoride contents in water samples

Samples 1 2 3 4 5 Average
Fluoride content(ppm) 10.8 11.2 11.2 10.6 11.7 11.10

Table 2: Table showing distribution of cases according to the toxic effects of fluorides

Toxic effects of Fluorides 5 -6 yrs 6 -7 yrs 7-8 years 8 – 9 yrs 9 –10 yrs Total
Dental fluorosis 16 (19.5%) 16 (19.5%) 16 (19.5%) 17 (20.7%) 17 (20.7%) 82 (100%)
Skeletal fluorosis 0 (00%) 0 (00%) 0 (00%) 0 (00%) 5 (100 %) 5 (100%)
Gastrointestinaldyspeptic symptoms 6 (25%) 5 (20.3%) 5 (20.3%) 4 (16.7%) 4 (16.7%) 24 (100%)
Non–skeletal Manifestations 6 (12.7%) 7 (14.9%) 10 (21.2%) 11 (23.4%) 13 (27.6%) 47 (100%)

Table 3: Table showing results of the investigations

  5 -6 yrs 6 -7 yrs 7 – 8 yrs 8 – 9 yrs 9 – 10 yrs Total
Stool test 2 (50%) 1 (25%) 1 (25%) 0 (00%) 0 (00%) 4 (100%)
Radiological examination 00 (00%) 00 (00%) 00 (00%) 02 (20%) 8 (80%) 10 (100%)
Gastrointestinal endoscopy 9 (25%) 9 (25%) 7 (19.4%) 6 (16.7%) 5 (13.9%) 36 (100%)


In this study, dental fluorosis was most common and ear-liest sign to appear afflicting 82% of children. The preva-lence was high and almost same (19.5-20.7%) in different age groups. It can be minimized by consumption of food rich in calcium and vitamin D. Calcium binds with excess fluorides and helps in safe excretion of fluorine and also replenishes body calcium stores depleted by fluorides hence fluorosis occurs after long term exposure in children taking diet rich in calcium and vitamin D. The prevalence of skeletal fluorosis was zero among children below 9 years. Only 5 children from the highest age group (9 – 10 years) had features of skeletal fluorosis because it occurs after long term exposure to fluorides. Similarly non – skeletal manifestations were more prevalent (27.6%) in elder children due to long term exposure.

The gastrointestinal symptoms were more prevalent (25%) amongst young children than elder children (16.7%). It indicates the early onset of dyspeptic symptoms in children which disappear or diminish probably due to decreased susceptibility of gastrointestinal mucosa to degenerative effects of fluorides after long term exposure.

Skeletal fluorosis was found in 5 cases but the radiological changes were seen in 10 cases. The gastrointestinal manifestations were found in 24 cases but the endoscopy revealed mucosal changes in 36 cases. The investigations indicate the involvement of bones and gastrointestinal mucosa in symptomatic as well as few asymptomatic cases. One of the most fascinating aspects is susceptibility to fluoride toxicity. In spite of consuming high doses of fluoride few children were asymptomatic where as others had severe health complaints.

A study was conducted in Nalgonda district from June 2006 to May 2007 on the school children aged between 13 – 15 years. The study indicated that although the fluoride content of the water samples collected was variable (1 – 9ppm) but the prevalence of fluorosis was 100% at all levels. It could be due to consumption of fluoride rich food like rice and tea grown in the area as described elsewhere [9].

A clinical and biochemical study of chronic fluoride tox-icity in children was conducted in the neighbor state, Karnataka at Gulbarga district. According to the study the fluoride content were between 0.6 – 13.4 ppm. The study revealed that 89% of the children had dental fluorosis and

39% exhibited skeletal fluorosis which was marginally high in elderly children. On investigations, serum samples of the children showed elevated levels of Alkaline Phos-phatase and radiographic changes were suggestive of osteoporosis, osteosclerosis and genu valgum in elderly children [10].

There are several possible reasons for asymptomatic con-dition like different excretory functions of kidneys or different circulating levels of hormones (Parathormone, Calcitonin and steroids) or it might be dietary factors (Calcium and vitamin C). However susceptibility to fluoride toxicity requires further investigations.

Fluoride in the contaminated water neither can be seen nor tasted therefore water must be tested and provisions should be made to provide safe drinking water to school going children. Secondly, the rural populations generally do not understand the role of fluoride poisoning in the crippling disease so they should be made aware by health education and motivated to drink defluorinated water strictly.

There are following ways to get safe drinking water:

  1. Dig deeper tube well (the chances of getting safe water is 50%)
  2. Deliver safe water through pipelines.
  3. Defluorinate the water – The following tech-niques are being practiced in India-
    1. The Nalgonda technique – the application of alum, lime and bleaching powder in controlled condition.
    2. Adsorption by activated alumina or carbon.
    3. Ion exchange and Reverse osmosis.

The first two techniques can be easily implemented in rural areas where Ion exchange and Reverse osmosis are not available.


It is clear from the observations presented in this article that fluoride damages teeth, skeletal and non – skeletal systems including gastrointestinal mucosa in children. Dental fluorosis was common in all age groups but severe in elder children. Skeletal fluorosis and non- skeletal manifestations occur after long term exposure but gastrointestinal mucosa is more vulnerable to fluoride toxicity in lower age groups.


  1. Short, HE, Robert MC. Endemic fluorosis in the Madras Presidency. Indian J. Med. Res. 1973; 25: 553 -558.
  2. Susheela AK, Das TK, Khurana. Circulating level of sialic acid and glycosaminoglycans, a diagnostic test for ankylosing spondylitis. Ann. Rheum. Dis. 1988; 47, 833-837.
  3. Viswanathan G, Jaswant A, Gopalakrishnan S, Sivailango S, and Aditya G. Determining the optimal fluoride concen-tration in drinking water for fluoride endemic regions in south India. Science of the Total Environment. October 2009; 407(20): 5298 – 5307.
  4. Nanda RS. Fluoride content of North Indian foods. In-dian J. Med. Res 1972; 60, 1470-1482.
  5. Susheela A K. Epidemiological studies of health risks from drinking water naturally contamination: Approaches and Application. 1995; IAHS publ. no.233: 123 – 134.
  6. Colin-Jones DG, Bloom B, Bodemar G. Management of dyspepsia: Report of a working party. Lancet 1988; 1: 576-579
  7. Jolly SS, Prasad, Sharma. Endemic fluorosis in India. J.Assoc. Physians India 1970; 18: 459-471.
  8. Susheela AK. and Majumdar K. Fluorosis control pro-gramme in India, Proc. 18th WEDC Conference in Nepal 1992; 229-334.
  9. Sudhir KM, Prashant GM, Reddy VVS. Prevalence and severity of dental fluorosis among 13- to 15- year old school children of an area known for endemic fluorosis: Nalgonda district of Andhra Pradesh. Journal of Indian Society of Pedodontics and Preventive Dentistry 2009, 27(4):190-196.
  10. Shrivashankara AR, Shivaraja Shankara YM & Hanu-math Rao S. Research Report on Fluoride, 2000;33 (2): 66-73


Biomedical Research Volume 21 Issue 3
Biomedical Research 2010; 21 (4): 423-427

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