Research Article

Endemic Dental and Skeletal Fluorosis: Effects of High Ground Water Fluoride in some North Indian Villages

Apurva K Srivastava, Aditi Singh, Subhash Yadav, Asha Mathur.

Abstract

Objectives: To identify the endemic high fluoride areas and to study the effects of high water fluoride in the population residing in these areas. Methods: A water survey from different areas was utilized to identify high fluoride area in some districts of Uttar Pradesh, India. Pretested questionnaires was prepared to record dental fluorosis grades, nutritional and socio-economic status, education, occupation, by house to house survey of 10,000 population. Subjects were clinically examined for dental and skeletal fluorosis. Results: In villages of Unnao district mean water fluoride level in ground water ranged from 1ppm to 10.5ppm. Out of a population of 5024, 43% had fluorosis (dental and skeletal). The prevalence of dental and skeletal fluorosis was 28.6% and 14.2% respectively. Dental fluorosis was highest in 13-15 years age group with boys more commonly affected than girls. Conclusion: Fluorosis incidence is directly related to fluoride intake through drinking water. Fluorosis (both dental and skeletal) was prevalent in the villages with water fluoride levels more than 1ppm. Fluorosis increases from 5 to 15 years of age, highest in 13-15 years age, as water (and hence fluoride) consumption increases in growing age and also because amelogenesis and enamel maturation is also taking place, thus making the enamel more susceptible. Majority of the population above 40 years of age were partially or completely edentulous, emphasizing that dental fluorosis as being one of the primary causes.

Keywords: Endemic; Dental Fluorosis; Fluoride; Enamel Hypoplasia; Heavy Water; Minerals

Apurva K Srivastava, Aditi Singh, Subhash Yadav, Asha Mathur. Endemic dental and skeletal fluorosis: Effects of high ground water fluoride in some North Indian villages. International Journal of Oral & Maxillofacial Pathology; 2011:2(2):7-12. ©International Journal of Oral and Maxillofacial Pathology. Published by Publishing Division, Celesta Software Private Limited. All Rights Reserved.

Received on: 24/03/2011 Accepted on: 11/06/2011

Introduction

Fluorosis is defined as enamel hypoplasia caused by the ingestion of excess fluoride during the time of enamel formation. The permanent teeth are often affected, though it occasionally affects primary teeth.1 The main source of fluoride is through drinking water. Thus the safe limit of fluoride in drinking water is approximately 1.0ppm.2

Fluorosis affects almost all the major systems of the body including gastrointestinal system, nervous system and reproductive system. But skeletal system and teeth are most affected. Clinical dental fluorosis is often considered as an irreversible disease.3

India lies in a geographical fluoride belt, which extends from Turkey up to China and Japan through Iraq, Iran and Afghanistan. Of 85 million tons of fluoride deposits found on the earth's crust, nearly 12 million tons are in India.4 Fluorosis is an endemic condition prevalent in 17 states of India.5 Out of six lakhs villages in India at least 50% have fluoride content in drinking water exceeding 1.0ppm.6 Though mortality by chronic fluoride exposure is quite low morbidity is high, ranging from 9.3% to 27.7% for skeletal fluorosis and 35.0% to 69.0% for dental fluorosis.7,8 Endemic fluorosis continues to be a challenging national health problem, particularly in the states of Andhra Pradesh, Punjab, Haryana, Uttar Pradesh, Rajasthan, Gujarat, Maharashtra and Tamil Nadu.6 It is a paradox that while fluorosis is such a challenging national problem, the use of fluoride in drinking water, toothpastes, gels etc. is still being advocated.9,10,11,12.

The Aims & Objectives of the present study is to identify the incidence and prevalence of dental and skeletal fluorosis in high fluoride areas in relation to age and sex.

Materials and Methods

To select the study area, 146 drinking water samples were collected in sterile containers from different sources like wells, hand pumps, government water supply in 21 different villages and cities of Lucknow, Unnao and Barabanki districts of Uttar Pradesh, India and sent to Endocrinology department, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow for fluoride level estimation, which was done by fluoride ion analyzer (Expandable Ion

analyzer EA 940 Orion). It was observed that majority of the villages in Unnao district had mean water fluoride level more than 1 ppm. In some, it ranged from 2-4 ppm, while Maheshkhera village of Unnao had a maximum fluoride content of 10.5 ppm in ground water. Hence villages of Unnao interior were selected because of very high fluoride content in water.

Criteria for Selection of sample

Those villages of Unnao district which had maximum average content of fluoride in water consisted of 6 villages (Marksnagar, Maheshkhera, Makur, Dharakhera, Marocha, and Jarurakhera) were selected and house to house enumeration of the population was done. The combined population of these villages was found to be 6005, but at the time of examination 981 individuals were not available leaving a total of 5024 (approximately 84%) subjects who were clinically examined in detail by the dental surgeon in broad day light.

Examination and Collection of Data

The cotton rolls were used to isolate and dry the teeth and diagnostic dental instruments (mouth mirror and probe) were used to examine the teeth. Ethical approval was received by the Sanjay Gandhi Post Graduate Institute of Medical Sciences’ Human Research Ethics Committee. Participants also provided written consent prior to the examination and investigations. Similarly a population of 5121 individuals from the villages of Barabanki was surveyed as control as water fluoride level was less than 1ppm. The dental fluorosis was classified using the WHO criteria and Dean’s index.1,13

Two structured close ended pre tested questionnaire were prepared to record the data having details about factors which have been identified as potential risk factors for fluorosis.14,15 The first one had information about socio-economic status, occupation, education, source of drinking water, while the second one had details of dental fluorosis, any relevant medical / dental history, diet especially diet rich in calcium, fish intake, the use of fluoride containing tooth paste. Inclusion criterion was Life time residents of the area and exclusion criteria was partially / unerupted teeth in children.

A cross sectional study was performed, house to house survey was done. 50 sets of diagnostic instruments which had been autoclaved at Saraswati Dental College, sufficient cotton, chemical sterilizers were carried by the team in an autoclave drum to the study area. 40-50 patients were examined in a day.

A subsample of population was re-evaluated for the presence or absence of dental fluorosis by the dental surgeon on a second occasion, approximately one month after the first examination. The examiner was blinded to the results of the first examination. The agreement between the two sets of readings obtained on two different occasions was used as a measure of intra- observer reliability.

The data was entered on the Microsoft excel sheet on computer with variables like age, sex, education, occupation, average annual income, dietary intake and the Deans index for dental fluorosis and statistical analysis was performed using SPSS PC version 10 software. The percentage prevalence of dental fluorosis was calculated by taking the number of cases of dental fluorosis as the numerator and total population as the denominator and multiplying it by 100. The individuals were then divided into different age groups and according to the grading of dental fluorosis to assess the data. The association between different types of fluorosis and age, sex, and the source of water supply was investigated by the non-parametric chi-square (χ2).

Results

We ascertained the fluoride level in drinking water from different sources (wells, hand pumps, tube well, government water supply) in the villages of Lucknow, Barabanki, and Unnao districts. It was observed that for majority of the village population wells and hand pumps was the major source of drinking water (Table 1 & 2). In villages of Unnao district mean water fluoride level in ground water was more than 1 ppm up to 10.5 ppm, and on this basis six villages (Marksnagar, Maheshkhera, Makur, Dharakhera, Marocha, and Jarurakhera) were selected for the study. A total of 5024 population in seven villages wherein the male: female ratio was approximately 52:48 (Table 2A). In the control group the ratio was 53:47 among 5121

population from the villages of Barabanki district (Table 2B). Difference in the prevalence of Fluorosis in Study and Control area was highly significant (p<0.001).

A. Study area: villages of unnao district(u.p.)

Sl.No

Name of the district

Average Fluoride level (ppm) Hand pump (maximum fluoride level given in brackets)

Average Fluoride level (ppm) Well (maximum fluoride level given in brackets)

Average Fluoride level (ppm) Govt. Water supply (maximum fluoride level given in brackets)

1

Mahesh khera

6.96 (10.5)

4.525 (6.8)

-

2

Marksnagar

2.30 (6.4)

4.26 (5.9)

0.60 (1.2)

3

Makur

1.706 (4.6)

2.32 (4.1)

0.772 (0.9)

4

Jaruakhera

1.589 (3.9)

2.163 (2.8)

-

5

Marocha

1.498 (4.2)

2.134 (3.8)

6

Dharakhera

1.378 (3.8)

1.768 (2.9)

B. Control area: villages of barabanki district (u.p.)

Name of the district

Hand pump

Well

Govt. Water supply

7

Muzzafarma

0.91

1.06

-

8

Moradabad

0.42

0.748

-

9

Nargismau

0.947

1.01

-

10

Sarsaundi

0.250

-

-

C. Areas of Lucknow district (not selected in the study)

11

Gomti Nagar

1.321

-

0.975

12

Uttrathiya

1.129

-

0.942

Table 1: Water fuoride level in different villages of Unnao, Lucknow and Barabanki districts

Variable

Value

Total Population

5024

Male:Female Ratio

52:48

Well water for drinking

32%

Hand pump water for drinking

64%

Government water supply

4%

Average water fluoride level

2.32 ppm

Population affected with both dental and skeletal fluorosis

43%

Population affected with dental fluorosis

28.64%

Table 2A: Characteristics of study group (High fluoride area)

Variable

Value

Total Population

5121

Male:Female Ratio

53:47

Well water for drinking

12%

Hand pump water for drinking

56%

Government water supply

32%

Average water fluoride level

0.945 ppm

Population affected with both dental and skeletal fluorosis

2.19%

Population affected with dental fluorosis

1.99%

Table 2B: Characteristics of control group (low fluoride area)

Incidence of fluorosis:

In the selected villages of Unnao and Barabanki districts, every individual was examined for fluorosis & grading done according to Dean’s index. In the high fluoride villages of Unnao district, out of a population of 5024, 43% had fluorosis (dental and skeletal) of which 28.64% had dental fluorosis (Table 2A), skeletal fluorosis was seen in 712 cases (14.17%). In the control (low fluoride) group from Barabanki district, 1.99% of population had dental fluorosis among 2.19% affected with both dental and skeletal fluorosis. (Table 2B).

Skeletal fluorosis

It is characterized by immobilization of joints of the axial skeleton and of the major joints of the extremities. There is difficulty in walking, bending, moving and ultimately the patient is crippled and incapacitated. In the initial stage of skeletal fluorosis, patients complained of pain in the bones and joints; sensations of burning, pricking, and tingling in the limbs; muscle weakness. Later on the extremities become weak and moving the joints is difficult. The vertebrae partially fuse together, crippling the patient.

The skeletal fluorosis was graded according the clinical signs and symptoms as Asymptomatic phase (Preclinical phase), Early symptomatic phase (Clinical phase I), Established skeleton phase, Phase of complication crippling fluorosis and Phase of incapacitation. Highest incidence of Skeletal fluorosis was in age group 41 plus, the incidence was significantly (p <0.01) higher than that of all the other age groups. Some of them were showing early symptomatic presentation of fluorosis while others had severe crippling fluorosis also (Table 3).

Dental Fluorosis

Dental fluorosis was present in 1439 out of 5024 people, giving a prevalence rate of 28.64% (Table 4). Different grades of dental fluorosis were observed - Questionable 602 (11.98%), Very Mild - 374 (7.44%), Moderate - 330 (6.57%), moderately severe - 72 (1.43%), Severe - 61 (1.21%). It was found that prevalence was lowest in children of 1-5 age group (6.30%), and maximum in 13-15 age group (61.79%) which was statistically significant (p<0.01). After the age of 15 years the prevalence of dental fluorosis gradually declined. Large number of the cases was showing moderately high to very severe involvement of the teeth.

Age group

Total surveyed

Early sympt.

%

Estab. Sympt.

%

Crippling

%

Incap.

%

Total

%

0-5

683

0

0

0

0

0

0

0

0

0

0

6-12

914

0

0

0

0

0

0

0

0

0

0

13-15

390

5

1.28

3

0.77

0

0

0

0

8

2.05

16-30

1348

30

2.23

33

2.45

21

1.56

0

0

84

6.23

31-40

684

48

7.02

47

6.87

26

3.80

0

0

121

17.69

41+

1005

249

24.78

198

9.70

43

4.28

9

0.90

499

49.65

Total

5024

332

6.61

281

5.60

90

1.79

9

0.18

712

14.17

Table 3: Age and grade wise distribution of skeletal fluorosis.

Age group

Total population

Que(?)

%

Mild

%

Mod

%

Mod-Seve

%

Severe

%

Total

%

0-5

683

27

3.95

15

2.20

0

0

1

0.15

0

0

43

6.30

6-12

914

191

20.90

121

13.23

55

8.05

7

0.77

8

0.88

382

41.79

13-15

390

124

31.79

38

9.74

63

6.89

11

2.82

5

1.28

241

61.79

16-30

1348

173

12.83

123

9.12

76

5.64

32

2.37

30

2.23

435

32.27

31-40

684

61

8.92

41

5.99

65

9.50

9

1.32

13

1.90

188

27.49

41+

1005

26

2.58

36

3.58

71

7.06

12

1.19

5

0.50

150

14.93

Total

5024

602

11.98

374

7.44

330

6.57

72

1.43

61

1.21

1439

28.64

Table 4: Age and grade wise distribution of dental fluorosis.

Discussion

Excessive fluoride concentrations have been reported in ground waters of more than 20 developed and developing countries including India where 19 states are facing acute fluorosis problems.16 Clinical dental fluorosis has been described as the most convenient biomarker of fluoride exposure. The maximum permissible safe limit of fluoride in drinking water is < 1.0ppm. Long term ingestion of fluoride in drinking water leading to dental fluorosis, a visible discoloration from white spots to brown and black stains has been well established. It has been shown that cessation of water fluoridation has caused significant reduction in dental fluorosis.17 There is no specific antifluorotic drug available. In the present study in rural areas around Lucknow, Uttar Pradesh especially in interior villages of Unnao, drinking water fluoride concentration was found to be from 1ppm to 10.5ppm. A population of 5024 from this fluoride endemic zone was studied for fluorosis. Fluorosis incidence is directly related to drinking water fluoride intake. Fluorosis (both dental and skeletal) was prevalent in the villages with water fluoride levels more than 1ppm. The prevalence of fluorosis both dental and skeletal was 43% of which 28.64% (1439) had dental fluorosis. Out of a total of 5024 population, skeletal fluorosis was seen in 712 cases (14.11%). Fluorosis is an endemic problem in India and the prevalence varies from 16 to 36%.18,8 There is compelling evidence that the prevalence of dental fluorosis has increased in the United States, Canada, Ireland and other parts of the world in recent years.19,20 We have also observed a significant increase in the prevalence of dental fluorosis with increase in fluoride content in drinking water. A stepwise increase in the prevalence of dental fluorosis with the corresponding increase in water fluoride content was seen by Chandrashekhar and Anuradha.21

Our study has shown that the prevalence of dental fluorosis was lowest in children of 0-5 years and gradually increased with age up to 15 years. Low incidence of dental fluorosis in younger age group and gradual increase from 5 to 15 years of age has been identified in other parts of India.17,22 The exact mechanism involved in this is not known. A high fluorosis incidence above 5 years of age may be because with growing age, fluoride consumption increases with increase in quantity of drinking water. Also during this age amelogenisis is taking place and hence enamel is very susceptible to any attack. Therefore a reliable community study is desirable to clinch the diagnosis in early phase and treat the patients. We found a higher predilection of dental fluorosis in males than in females. This could be due to migration of women from low fluoride areas to these villages after marriage.

Few studies have shown enhanced incidence amongst girls than in boys8 or that both the sexes were equally affected.23 Higher fluorosis levels have been

demonstrated by Whelton et al amongst lifetime residents of fluoridated communities.24

In the study area we found that majority of the population above 40 years of age was partially or completely edentulous, as dental fluorosis being one of the primary cause. Edentulous people suffer nutritional deficiencies, being unable to chew, also experienced difficulty in speaking and esthetics compromised. While in the younger population it causes psychological trauma due to discoloration and destruction of the teeth.

The longitudinal study of children from birth to nine months old conducted by Levy et al.25 showed that ingestion of fluoride through water, supplements and toothpaste greatly contributed to the proportion of fluoride ingested beyond the "optimum" recommended level.

Conclusion:

Endemic skeletal fluorosis continues to be a challenging national health problem in India. In summary, it is very important to assess the benefits of fluoride as a method for caries prevention; however, the risk to fluorosis should also be considered, since its availability from several sources might easily lead to doses above the recommended levels, contributing to an increase in the prevalence of fluorosis. In determining the optimum fluoride levels of a water supply, the climate, source of water supply, drinking habits, and other factors influencing the quantity of water ingested should be carefully considered. Active steps must be taken to partially defluoridate the water before distribution to reduce the morbidity associated with fluorosis. Similar surveys are required in other parts of India to identify areas with high water fluoride content and determine the extent and manner in which defluoridation can be carried out.

Author affiliations

1. Apurva K Srivastava, 2. Aditi Singh, Department of Pathology & Microbiology, Saraswati Dental College, Faizabad Road, Lucknow. 3. Subhash Yadav, Department of Endocrinology, Sanjay Gandhi Post Graduate Institute of Medical Sciences. 4. Asha Mathur, Department of Pathology & Microbiology, Saraswati Dental College, Faizabad Road, Lucknow.

Acknowledgments

We would like to acknowledge the Department of Biotechnology, Government of India, New Delhi for their financial assistance and support to carry out this study.

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Corresponding Author

Apurva K Srivastava,

Department of Pathology and Microbiology,

Saraswati Dental College & Hospital,

Faizabad Road, Lucknow, India.

Email id: dr.aksrivastav@gmail.com

Conflict of Interest: None Declared.

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