Prevalence of dental fluorosis and associated risk factors in Alappuzha district, Kerala

Background. Fluorosis is considered endemic in 15 states of India. Dental f luorosis is the mast convenient biomarker of exposure to fluoride. In Keral a, although the condition is reported to be endemic in the districts of Ala ppuzha and Palakkad, there are no systematic epidemiological studies evalua ting dental fluorosis. We studied the prevalence of dental fluorosis among school children in Ambalappuzha taluk, Alappuzha district, Kerala and evalu ated the contribution of potential risk factors. Methods. We conducted a community based, cross-sectional survey of 1142 sch ool children (630 girls, 512 boys) in the age group of 10-17 years, using a multistage random cluster sampling technique. A pre-tested structured ques tionnaire was used to assess exposure to various sources of fluoride. A den tal specialist examined all the children to determine the presence or absen ce of dental fluorosis and graded the degree of dental fluorosis using Dean 's index. The water fluoride content in the study area was obtained from th e district water authority department; Bivariate associations were examined using the Chi-square and Chi-square trend tests, while multiple logistic r egression was used to evaluate the association of select risk factors with the presence or absence of dental fluorosis. Results. The overall prevalence of dental fluorosis in our study sample was 35.6% and the community fluorosis index was 0.69. The prevalence of dental fluorosis was higher in the urban compared to the rural areas (55.3% v. 16 .8%; p < 0.001), and in girls compared to boys (39.2% v. 31.3%; p < 0.01). The prevalence of dental fluorosis was higher among children who consumed p ipe water as compared to children who consumed well water (44.8% v. 12.7%; p < 0.001). We noted a step-wise increase in the prevalence of dental fluor osis with a corresponding increase in water fluoride content in different p anchayats (p = 0.024). The principal factor associated with the presence of dental fluorosis was a high fluoride content of drinking water (OR 1.85, 9 5% Cl: 1.17-2.92). We did not observe any significant association between d ental fluorosis and the intake of brick-tea, consumption of fish or the use of toothpaste. Conclusion. Dental fluorosis is a public health problem in the Ambalappuzha taluk. Active steps must be taken to partially defluoridate the water befo re distribution to reduce the morbidity associated with dental fluorosis in this area. Similar surveys are required in other parts of India to identif y areas with high water fluoride content and determine the extent and manne r in which defluoridation can be carried out.