5.1 Description of characteristics of population Bivariate analysis Stratified analysis

Transcription

1 Chapter 5 Results Page umbers 5.1 Descriptio of characteristics of populatio Bivariate aalysis Stratified aalysis Multivariate aalysis Estimatio of Attributable Risk percet Compariso of uriary fluoride level amog jowar cosumers Tables ad Figures

2 Chapter 5 Results 5.1 Descriptio of Characteristics of Populatio The tables 5.1 to 5.5 describe the characteristics of cases ad cotrols erolled i the study. Sice it was a umatched case cotrol study, there were variatios i demographic factors of cases ad cotrols. The cases were almost equal to calculated sample size of 375, but about 15 of the calculated sample size could ot be met as severe forms of fluorosis was ot oted i villages with low fluoride levels.(table 5.1 ad Table 5.2). The villages could ot be matched i terms of fluoride levels as the prevalece ad severity of detal fluorosis differed with each fluoride level i water. I medium fluoride villages, there were almost equal umber of cases (= 158) ad cotrols ( = 151) coformig to the estimated sample size. I the high fluoride villages, the total umber of cases ad cotrols were 97 ad 91 respectively. The table 5.2 shows the distributio of the cases ad cotrols accordig to idividual villages. There was a sigificat (p = 0.002) differece i proportios of age betwee the cases ad cotrols (Table 5.3). Although, the study desig could have matched the age group of years, it was ot feasible, as the study was coducted i three differet fluoride areas of rural settigs ad there was a variatio i attedace i higher secodary schools. Moreover, i a child above 12 years of age, there were hardly ay variatios i the occurrece of detal fluorosis. The study showed o sigificat liear tred i fluorosis as the age advaced. 121

3 Chapter 5 Results There was a sigificat differece i proportio betwee geders (Table 5.4) of cases ad cotrols. The female attedace i the school was less, whe compared to males ad thus it was ot feasible to match the geder. As the study was carried out i the rural settigs, factors such as occupatio of father, type of roof used for the house ad educatio of mother, were used to assess the socio-ecoomic status of the households. Iitially (Table 5.5) occupatio of subject s father was assessed i five categories which were agriculture (farmer), govermet sector, private sector, teacher ad others. Nearly 66 of subject s fathers were ivolved i agriculture, 14.7 were employed i govermet sector (Class IV), 5.8 were employed i private sector doig odd jobs, 5.3 of were employed as teachers (maily primary school) ad remaiig 9 were ot fully employed. Excludig agriculture category, the other occupatios were combied as others, for aalysis (Table 5.5A). Though there were differeces betwee the cases ad cotrols, with respect to occupatio of the subject s father, it was ot statistically sigificat. The educatio of the mother (Table 5.6) was assessed as a surrogate maker of socio ecoomic status (SES). The mother s of early 45.2 subjects had completed primary educatio, 34.2 had completed middle school educatio, 7.4 had completed high school educatio ad 13.2 had ot atteded school. Though there was sigificat differece betwee the cases ad cotrols accordig to the educatio levels of mothers, it did ot show ay liear tred. 122

4 Chapter 5 Results Type of roof (Table 5.7) was assessed as a part of SES marker, it was oted that 41.8 of study subjects lived i houses with thatched roof, 40.6 with tiled roof ad 17.6 were livig i houses with cemet roof. There was a sigificat differece (p=0.001) betwee cases ad cotrols based o the roof types. 5.2 Bivariate Aalysis The cases ad cotrols were compared with respect to a umber of variables such as jowar cosumptio, tea cosumptio, dietary habit, sex, type of roof etc. A umatched aalysis was carried out to calculate the crude odds ratio. Except for tea cosumptio, all the risk factors were sigificatly associated with detal fluorosis. Dietary habits showig a borderlie sigificace (p=0.058) were cosidered for further aalysis. Jowar cosumptio as a risk factor Jowar cosumptio (Table 5.8) was associated with detal fluorosis. The jowar cosumers had three times higher risk [OR 2.59 (95 CI 1.94 to 3.47)] for severe detal fluorosis as compared to the o-jowar cosumers. Jowar cosumptio ad severity of detal fluorosis The associatio betwee jowar cosumptio ad differet grades of detal fluorosis (severity grades) were assessed (Table 5.9 ad Figure 5.1). The sigificat effect of jowar cosumptio o detal fluorosis was evidet as jowar cosumers showed cosistetly higher prevalece i all grades scores 4, & 8 of Thylstrup ad Fejerskov (TF) idex of detal fluorosis whe compared to o- 123

5 Chapter 5 Results jowar cosumers. Figure 5.2 shows cumulative frequecy distributio of the proportio of teeth of childre exhibitig highest TF scores i differet fluoride areas. Table 5.10 shows the percetage of severe grades of detal fluorosis ad jowar cosumptio i differet fluoride villages. (Figure 5.3) TF idex scores of four ad five were commo i low fluoride villages. I the jowar cosumers, TF scores of four ad five were oted i 56.5 ad 40 idividuals respectively, while i case of o-jowar cosumers, it was oted i 43.5 ad 60 respectively. This variatio was ot statistically sigificat (p=0.139). I medium fluoride villages (Figure 5.4), TF idex scores of four, five, six ad seve o TF idex were recorded. A prevalece of 53.8, 86.1, 75 ad 66.7 for TF idex scores four, five, six ad seve respectively was oted i jowar cosumers, while i o jowar cosumers it was 46.2, 13.9, 25 ad 33.3 respectively. I fact, the proportio of cases amog o jowar cosumers was 60 higher tha jowar cosumers for score five of the idex. This variatio was statistically sigificat (p=0.001). I high fluoride villages (Figure 5.5), the jowar cosumers showed prevalece of 52.4, 72.1, 81, 81.8 ad for the TF scores of four five, six, seve ad eight respectively, whereas the o-jowar group showed, 47.6, 27.9, 19, 18.2 ad 0 for the same scores. This differece i observatio was statistically sigificat (p=0.001). Oly oe case showed TF score eight which is ot a usual fidig at this level of fluoride cocetratio i drikig water. 124

6 Chapter 5 Results Tooth Prevalece Tooth prevalece fluorosis (TPF subject scores with highest TF score) was used to express the extet of fluorosis i the subjects. This estimate was used because it icludes all the teeth preset ad is a parameter for the frequecy distributio of fluorosis. This distributio has bee recommeded to elucidate detal fluorosis i groups of subjects. Table 5.11 shows prevalece for detal fluorosis i differet teeth. The lower first premolars were most affected, followed by lower secod premolars, caies ad others. The premolars, caies ad secod molars were grouped as late eruptig teeth ad icisors ad first molars were classified as early eruptig teeth. The late eruptig teeth showed 91.4 prevalece of detal fluorosis, whereas the early eruptig teeth showed 8.6 (Figure 5.6). The Table 5.11A & Figure 5.7 shows percetage of cases accordig to the type of tooth with highest TF score amog jowar & o-jowar cosumers. Prevalece of fluorosis i late eruptig teeth was 52.5 amog jowar cosumers ad 29.8 i o jowar cosumers. I itraoral distributio, the madibular teeth showed cosistetly high severe TF scores whe compared to maxillary teeth, but it was ot statistically sigificat (Figure 5.8). I low fluoride areas upper teeth showed severe scores especially i icisors ad molars whe compared to their lower couterparts (Figure.5.9). I medium fluoride areas upper teeth (icisors, premolars ad molars) had severe scores whe compared to their lower couterparts (Figure. 125

7 Chapter 5 Results 5.10). I high fluoride areas, lower teeth (molars ad premolars) showed severe scores whe compared to their upper teeth (Figure. 5.11) Table 5.12 shows the tooth prevalece of detal fluorosis accordig to the age at which jowar was itroduced i the child s diet. The prevalece of detal fluorosis i early eruptig teeth was ad 8.3 for jowar cosumptio iitiated before six years, betwee six to eight years ad after eight years, respectively. The prevalece of detal fluorosis i late eruptig teeth was 30.5, 24.7 ad 9.1 for cosumptio of jowar before six years, betwee six to eight years ad after eight years respectively. The associatio betwee jowar cosumptio ad differet grades of detal fluorosis was assessed (Table 5.13). The earlier the cosumptio, (before six years ad betwee six to eight years) the higher was the TFI (4, 5, 6, 7, ad 8) scores tha for those cosumed at later years. There was a cosistet icrease i the occurrece of severe forms of detal fluorosis, if jowar was cosumed before six years of age. Hece if jowar is cosumed i later years, especially after eight years, there are fewer occurreces of severe grades of detal fluorosis. Geder ad severity of detal fluorosis Males had (Table 5.14 ad Figure & 5.12) 1.44 times higher risk for developig severe forms of detal fluorosis whe compared to females (OR CI ). This differece i observatio was statistically sigificat. Males showed cosistetly higher scores from four to eight o the scale of the Thylstrup ad Fejerskov idex, whe compared to females. This differece i observatio 126

8 Chapter 5 Results was ot statistically sigificat (p=0.84) i low ad medium fluoride areas. The differece i severe scores betwee geders was sigificat i the high fluoride areas (Figure 5.13). Age of subjects ad severity of detal fluorosis (Table 5.15) The 13 year olds had twice the risk of detal fluorosis (OR CI ), whe compared to the 12 year olds. Though the age of the subjects was sigificatly associated with severity of detal fluorosis, it did ot show ay liear tred. Fluoride level i drikig water as risk factor (Table 5.16) The subjects residig i high fluoride villages had two times (OR CI ) higher risk for detal fluorosis whe compared to those i low fluoride villages. Also, subjects i medium fluoride villages had twice the higher risk (OR CI ) for severe detal fluorosis, whe compared to those i low fluoride villages. The risk appeared to be similar i both high ad medium levels of fluoride levels i drikig water. Type of roof as risk factor (Table 5.17) The type of roof of the house where the study subjects were livig was used as surrogate marker for SES. The childre residig i thatched roof houses, had twice (OR CI ) the risk of developig severe forms of detal fluorosis whe compared to those residig i residig i houses with cemet roof. 127

9 Chapter 5 Results This risk was reduced to oe ad half times (OR CI ) i subjects residig i houses havig tiled roof, though it was ot sigificat. Nutritioal status Overall, 52 of the childre i the study could be classified as beig either uderweight or stuted or both. Over 20 of the study childre were severely malourished, havig a Z score less tha three stadard deviatios (SD) for ay idex. Height-for-age Nearly 23 of childre were severely stuted (Z score < 3 SD) (Table 5.18). The prevalece of stutig was more amog males whe compared to females, which was statistically sigificat (p=0.001 ad Table 5.19). The prevalece of stutig i subjects showed a sigificat icrease from 12 years to 15 years of age (p=0.001ad Table 5.20). However the stutig was ot associated with detal fluorosis (Table 5.18). Weight-for-age Five percet of childre were severely uderweight (Z score < 3 SD) (Table 5.21). The prevalece of uderweight was more amog females whe compared to males, which was statistically sigificat (p=0.006 ad Table 5.22). The prevalece of uderweight was associated (p=0.003) with age group of the subjects from 12 years to 15 years, but it did ot show ay sigificat liear tred. 128

10 Chapter 5 Results (Table 5.23) However beig uderweight was ot associated with detal fluorosis. Dietary habit as a risk factor The subjects who were o vegetaria diet had oe ad half times more risk (OR CI ) for severe forms of detal fluorosis whe compared to subjects who were havig mixed dietary habit. However this risk was ot sigificat (Table 5.24). Frequecy of jowar cosumptio The associatio of jowar cosumptio ad severity of detal fluorosis was further stregtheed by the frequecy of cosumptio (Table 5.25). Daily cosumers (who cosume jowar oce or twice a day) had three times higher risk (OR CI ) for severe detal fluorosis whe compared to ocosumers (oce a moth or occasioal cosumers). Study subjects who cosumed jowar 4-5 days a week (weekly cosumers) had two times more risk (OR CI ) for developig detal fluorosis, whe compared to o-jowar cosumers. There was a decreasig tred i the severity of detal fluorosis as the frequecy of cosumptio reduced. Those who cosume jowar two to three ad four days a week were grouped as weekly cosumers. There were oly 12 subjects i the category of oce a moth or occasioal cosumers who are grouped as o-cosumers. 129

11 Chapter 5 Results Effect of duratio of cosumptio There were seve categories accordig to age at which jowar were itroduced to the child s diet as described i the methodology sectio. It was regrouped as cosumptio which started before six years, betwee six to eight years ad after eight years of age. Oe of the sigificat fidigs of our study is the associatio of detal fluorosis i subjects accordig to the age of itroductio of jowar (Table 5.26 & Figure 5.14). Subjects who cosumed jowar earlier or before the age of six years had three times more risk (OR CI ) for detal fluorosis whe compared to the later year cosumers. Risk for detal fluorosis decreased to two times (OR CI ) whe subjects started cosumig jowar betwee ages of six ad eight years. If the child started cosumig jowar after eight years of age, there was o sigificat risk for detal fluorosis. Hece earlier the cosumptio of jowar, higher was the risk for detal fluorosis. The mea quatity of daily cosumptio of jowar i grams was assessed by a 24 hour recall method (Table 5. 27). The mea daily cosumptio of jowar amog cases was 131 ± gms ad i cotrols, it was ± gms. This differece i mea daily jowar cosumptio was statistically sigificat (p=0.001). A scale was prepared usig percetiles at 25 th, 50 th ad 75 th of the jowar cosumptio ad was grouped ito five itervals as show i Table The proportio of cases icreased from 5.4, 27.6, 26.1, & 5.7 as the mea daily cosumptio of jowar icreased from 0 to 95gms, 95 to 205 gms, 205 to 300gms 130

12 Chapter 5 Results ad 300 gms thereafter respectively. Whereas i cotrols, it was , 14.3 ad 3 for the same mea jowar cosumptio. There were 35.2 o cosumers i cases ad 58.4 o jowar cosumers i cotrols. The table 5.29 shows the mea jowar cosumptio amog the exposure group. The mea cosumptio amog the jowar cosumers were ±77.95gms ad o jowar group were 4.16±25.66gms of jowar. The 12 occasioal cosumers of jowar were icluded i the o jowar group. 5.3 Stratified Aalysis Stratified aalysis was carried out to recogize, ad study ay possible iteractios betwee two variables. A sigificat differece betwee the stratum specific odds ratio idicate the presece of iteractio. A sigificat differece betwee the uadjusted odds ratio ad the Matel Haeszel odds ratio idicates cofoudig. All the variables were subjected to stratificatio, but very few showed cosiderable differeces betwee the stratum specific odds ratios. The Matel-Haeszel odd ratio also failed to show ay marked differece from the respective odds ratio. This idicates that there is o possible iteractio or cofoudig preset. Jowar cosumptio, detal fluorosis ad fluoride i drikig water The crude odds ratio for jowar cosumptio ad detal fluorosis was To evaluate the effect of fluoride i drikig water ad jowar cosumptio o detal fluorosis, stratified aalysis was carried out. It was foud that the odds 131

13 Chapter 5 Results ratio was differet from the crude ratio (Table 5.30). At each stratum, for low, medium ad high fluoride villages, the odds ratios for jowar cosumptio ad detal fluorosis were 1.59, 3.18 ad 3.76 respectively. The associatio betwee exposure ad disease differ i each strata of the populatio. These differet strata specific odds ratios, suggest some mechaism of iteractio betwee jowar cosumptio ad fluoride i drikig water which ehaces detal fluorosis especially i medium ad high fluoride area. The Matel-Haeszel Odds ratio was 2.58 (p value = 0.001) which is similar to crude odds ratio. Hece jowar is ot a cofouder, but appears to be a effect modifier i the causal pathway of fluoride i drikig water ad detal fluorosis. The test of homogeeity (Breslow test) was border lie sigificat (p value = 0.05) for these strata specific odds ratio suggestig that it is ot a radom variatio. Hece if a child is livig i high fluoride area ad is a jowar cosumer, he has four (OR 3.76) times the risk of developig severe forms of detal fluorosis whe compared to o jowar cosumers, which is the excess risk from crude odds ratio of If the child is livig i medium fluoride area ad is a jowar cosumer, he has 3.06 times more risk for severe forms of detal fluorosis whe compared to o jowar cosumers, which is a excess risk from crude odds ratios of

14 Chapter 5 Results Geder, Detal fluorosis ad jowar cosumptio The crude odds ratio for jowar cosumptio ad detal fluorosis was To evaluate the effect of geder i the associatio betwee detal fluorosis ad jowar cosumptio, a stratified aalysis was carried out. It was foud that the odds ratio was differet from crude ratio (uadjusted) (Table 5.31). I the male stratum, the odds ratio for jowar cosumptio ad detal fluorosis was 3.42 whereas it was 1.93 for females. The associatio betwee exposure ad disease differ i strata of the populatio accordig to geder. These differet strata specific odds ratios suggest some mechaism of iteractio betwee jowar cosumptio ad geder, which ehaces detal fluorosis especially i males whe compared with females. The Matel-Haeszel commo odds ratio (p value = 0.001) for geder ad jowar cosumptio was 2.60, which is similar to crude odds ratio of 2.58, Therefore, geder is ot a cofouder, but appears to be a effect modifier i the causal pathway of jowar cosumptio ad detal fluorosis. The test of homogeeity (Breslow test) was sigificat (p value = 0.05) for these strata specific odds ratio suggestig that it is ot a radom variatio. I bivariate aalysis, though males showed a higher risk, it was ot sigificat. 133

15 Chapter 5 Results 5.4 Multivariate Aalysis As it was a umatched case cotrol study, factors that appeared to be associated with severity of detal fluorosis; (P < 0.2) were carried forward to a multivariate model (Table 5.32). The stepwise method was used for regressio. I multivariate model, the associatio of jowar cosumptio with severity of detal fluorosis persisted eve after the adjustmet of potetial cofouders (Table 5.32). The crude OR 2.59 icreased to OR 2.67 (95 CI 1.98 to 3.62) for jowar cosumptio i detal fluorosis after passig through the multivariate model. The study subjects livig i high fluoride areas ad cosumig fluoride through drikig water had a two times hihger(or CI 1.27 to 2.85) for developig severe detal fluorosis whe compared to subjects livig i low fluoride areas. Males retaied a risk of 1.58 times (95 CI 1.16 to 2.15) for developig severe forms of detal fluorosis whe compared to females. A vegetaria dietary habit of study subjects appeared to be more sigificatly associated with detal fluorosis whe compared to mixed diet ad also had 1.43 higher risk (95 CI 1.05 to 1.94) as compared to o vegetaria diet. The cemet house roof (oe of the surrogate marker of SES) had a protective effect (OR CI 0.29 to 0.70) for severity of detal fluorosis i study subjects. Diagostics of the multivariate model It is importat to examie the adequacy ad fitess of statistical model for multivariate aalysis. I regressio aalysis, the variety of residues, measures of ifluece, ad idicators of colliearity idetifies the model for fitess. There are 134

16 Chapter 5 Results two other core diagostic plots i logistic regressio aalysis which are directed at determiig the fitess of model. We used the followig plots to determie the fitess of the model. 1. Plot Square of Stadardized agaist Predicted Probability (Figure 5.15) 2. Plot Square of Deviace agaist Predicted Probability (Figure 5.16) Whe a U shape curve is formed by iteractio of these two lies (square of stadardized ad predicted probability) the it sigifies fitess of the model. Daily jowar cosumers were two times (OR CI 1.64 to 3.09) more likely to have severe detal fluorosis as compared to o cosumers. Childre who cosumed jowar four to five days a week had 1.68 times (95 CI 1.31 to 3.45) higher risk for developig detal fluorosis as compared to o jowar cosumers. Oe of the sigificat fidigs of our study was the associatio of detal fluorosis with the age of itroductio of jowar i child s diet. Subjects who cosumed jowar before the age of six years (OR CI 2.91 to 3.25) ad betwee six to eight years of age (OR CI 1.19 to 2.98) had higher risk of severe detal fluorosis whe compared to o jowar cosumers (Table 5.32). The frequecy of cosumptio, the age at which jowar was itroduced i child s diet ad occurrece of severe detal fluorosis was aalyzed usig stepwise multivariate model, for potetial cofouders like age, sex ad fluoride areas separately to avoid colliearity (Table 5.32). 135

17 Chapter 5 Results 5.5 Estimatio of Attributable Risk Percet. Attributable Risk Percet refers to EXPOSED persos ad it quatifies disease burde i the group, which ca be attributed to exposure. What is the proportio of disease amog the exposed which Ca be attributed to the exposure? Could be avoided by elimiatig the exposure? 2.67 is odds ratio for jowar cosumptio ad severity of detal fluorosis Attributable Risk percet = (OR 1) / OR x AR = ((2.67 1) / 2.67) x = 62.5 Therefore about 63 of detal fluorosis (severe) cases amog jowar cosumers ca be attributed to their jowar cosumptio. It ca also mea that 63 of detal fluorosis (severe) cases amog jowar* cosumers could be preveted if they had ever cosumed it. Estimatio of Populatio Attributable risk Percet Populatio Attributable Risk (Refers to both EXPOSED ad NONEXPOSED persos) commuity 1. Excess risk of disease i total populatio attributable to exposure 2. Reductio i risk achieved whe populatio is etirely uexposed 3. Helps determiig exposures relevatto public health i PAR = {(*Pco) (OR 1) / [(Pco) (OR-1)] + 1} x, where *Pco = of cotrols exposed populatio exposed. (Assumig that the proportio of 136

18 Chapter 5 Results exposed cotrols is the represetative of the proportio exposed i the source populatio sice it is a commuity based case cotrol study). PAR = {(*Pco) (OR 1) / [(Pco) (OR-1)] + 1} x Cases Cotrols Jowar cosumers No Jowar cosumers Proportio cotrols exposed = = PAR = = 39.9 The PAR was Therefore it ca be deduced that about 40 of detal fluorosis amog North Karataka populatio ca be attributed to jowar cosumptio or it meas that 40 of detal fluorosis (severe) cases could be preveted, if the people i these areas delayed the cosumptio of jowar util they are eight years of age 137

19 Chapter 5 Results 5.6 Compariso of Uriary Fluoride Level amog Jowar Cosumers The total umber of jowar cosumers was 394 (50.5 ) ad o jowar cosumers was 386 (49.5) The mea uriary fluoride levels were1.00±0.33 ppm i low fluoride villages, 1.39 ± 0.63 ppm i medium fluoride villages ad 1.93± 0.71 ppm i high fluoride villages. The rage of uriary fluoride excretio level at various fluoride levels i drikig water is show i table The mea uriary fluoride level is highly correlated with fluoride level i drikig water. The Karl Pearso correlatio coefficiet r was 0.99 ad sigificat (p = 0.05). As the fluoride cocetratio i drikig water icreased from low to high fluoride villages, the excretio of fluoride i urie also icreased. Table 5.34 shows mea uriary fluoride level i ppm amog jowar ad o jowar cosumers. The mea uriary fluoride level amog jowar cosumes was 1.21 ± 0.57 ad for o jowar cosumers was1.37±0.65 ppm respectively. This differece i the uriary fluoride level betwee jowar ad o jowar cosumers was sigificat. The mea uriary fluoride levels amog jowar cosumers ad o jowar cosumers at three differet fluoride levels i drikig water (villages) are compared i Tables 5.35 ad 5.36 Figure The uriary fluoride level amog jowar cosumers was 0.97±0.31 ppm ad i o jowar cosumers was 1.04±0.35ppm i low fluoride areas. The jowar 138

20 Chapter 5 Results cosumers were excretig low levels of uriary fluoride whe compared to o jowar cosumers i low fluoride villages. The mea differece i uriary fluoride levels (-0.70 ppm) betwee jowar ad o jowar cosumers was ot statistically sigificat i low fluoride villages. The uriary fluoride level amog jowar cosumers was 1.20± 0.50 ppm ad 1.57±0.69 ppm amog o jowar cosumers, i medium fluoride area. The jowar cosumers were excretig low levels of uriary fluoride whe compared to o jowar cosumers, at medium level of fluoride i drikig water. This differece i uriary fluoride levels (-0.36 ppm) betwee jowar ad o jowar cosumers was statistically sigificat (p=0.001). I case of the high fluoride villages, the uriary fluoride level amog jowar cosumers was 1.67±0.57 ppm ad 2.25±0.75 ppm amog o jowar cosumers. The jowar cosumers were excretig low levels of uriary fluoride whe compared to o jowar cosumers. This differece i uriary fluoride levels (-0.58 ppm) betwee jowar ad o jowar cosumers was statistically sigificat (p=0.001). The mea uriary fluoride level of jowar cosumers at every scores o TF idex were sigificatly less whe compared to o jowar cosumers (Figure 5.18). The mea uriary fluoride level of jowar cosumers at every score o TF idex was less whe compared to o jowar cosumers i all three differet fluoride areas, but it was ot sigificat i low fluoride areas. (Figure 5.18) There was o differece i mea uriary fluoride levels betwee the age groups of 12 ad15 years (Figure 5.19) ad also betwee the geders (5.20). 139

21 Table 5.1: Distributio of cases ad cotrols i differet fluoride areas Villages Cases Cotrols Low fluoride area Medium fluoride area p value High fluoride area

22 Table 5.2: Distributio of study subjects - Idividual villages wise Villages Cases Cotrols Ajjihalli (0.69 ppm) Goviakovi (0.80 ppm) Nallur (0.83ppm) Sriramagodaahalli (1.34ppm) Madiur (1.51 ppm), Doddabathi (1.57 ppm), Telgi (2.63ppm) Hiremarehalli (2.72ppm) Bhauvalli (2.81ppm)

23 Table 5.3: Distributio of case ad cotrols accordig to the age i years Age (years) Cases Cotrols p value

24 Sex Cases Cotrols p- value Male Female Table 5.4: Distributio of cases ad cotrols accordig to Geder 143

25 Table 5.5: Occupatio of study subject s father Occupatio Subjects Agriculture Govermet Jobs Teacher Private Not fully employed

26 Table 5.5 A: Occupatio of study subject s father amog of cases ad cotrols Occupatio Cases Cotrols p- value Agriculture Others

27 Table 5.6: Distributio of cases ad cotrols accordig to educatio of study subject s mother Educatio of mother Cases Cotrols p value No schoolig Primary schoolig Middle Schoolig SSLC ad above

28 Table 5.7: Distributio of study subjects accordig to the type of house roof i which subjects were stayig Type of Roof Cases Cotrols p- value Thatched Tiles Cemet

29 Table 5.8: Distributio of Exposure- jowar cosumptio amog cases ad cotrols Jowar cosumptio Cases Cotrols Odds ratio 95 CI Cosumers ( ) No Cosumers

30 Table 5.9: Jowar cosumptio ad Severity of detal fluorosis (Scores of TF idex) Jowar cosumptio Severity of Detal Fluorosis(scores of T ad F Idex) Cases Cotrols ( o fluorosis) Yes No

31 Figure 5.1: Graph showig percetage of study samples with respect to TF scores (severe detal fluorosis) ad cosumptio of jowar i all three fluoride areas. 150

32 Figure 5.2: Cumulative frequecy disturbutio of the proportio of teeth of child exhibitig highest TF scores 151

33 Table 5.10: Jowar Cosumptio ad Severity of Detal Fluorosis (Scores of Thylstrup ad Fejerskov Idex) at differet Villages Village Jowar Cosumptio Severity of Detal Fluorosis(scores of Thylstrup ad Fejerskov Idex) Cases Cotrols Low Fluoride Villages Medium Fluoride Villages High Fluoride villages Yes# No Yes* No Yes* No *Severe detal fluorosis betwee jowar ad o jowar cosumers p = i high ad medium fluoride villages # Severe detal fluorosis betwee jowar ad o jowar cosumers was ot sigificat i low fluoride areas 152

34 Figure 5.3: Graph showig percetage of study samples with respect to TF scores (severe detal fluorosis) ad cosumptio of jowar i low fluoride areas 153

35 Figure 5.4: Graph showig percetage of study samples with respect to TF scores (severe detal fluorosis) ad cosumptio of jowar i medium fluoride areas 154

36 Figure 5.5: Graph showig percetage of study samples with respect to TF scores (severe detal fluorosis) ad cosumptio of jowar i high fluoride areas 155

37 Figure 5.6: Graph showig the percetage of teeth with highest TF score amog cases accordig to the eruptio sequece 156

38 Table 5.11: Shows type of teeth affected by most severe detal fluorosis amog jowar ad ojowar cosumers Teeth affected Lower first premolars Lower Secod Premolars Upper Caies Lower Caies Upper Secod Premolars Lower Secod molars Upper Secod Premolars Upper First Premolars Upper Lateral Icisors Upper Cetral Icisors Lower First Molars Sub (cases) No Fluorosis (cotrols) Jowar Cosumptio Yes No

39 Table 5.11A: Shows teeth affected by most severe detal fluorosis amog jowar ad o-jowar cosumers accordig sequece of eruptio. Early Eruptig Teeth Late Eruptig Teeth Cotrols Jowar cosumers No Jowar Cosumers

40 Figure 5.7: Graph showig percetage of cases exhibitig the teeth with highest TF score amog jowar cosumers ad No- jowar cosumers 159

41 Figure 5.8: Graph showig percetage of cases with respect to TF scores i their maxillary ad madibular teeth 160

42 Figure 5.9: Graph showig percetage of cases with respect to TF scores accordig to tooth type i low fluoride area 161

43 Figure 5.10: Graph showig percetage of cases with respect to TF scores accordig to tooth type i medium fluoride area 162

44 Figure 5.11: Graph showig percetage of cases with respect to TF scores accordig to tooth type i high fluoride areas 163

45 Table 5.12: Age at which jowar cosumptio was itroduced to child s diet ad prevalece of detal fluorosis- accordig to type of tooth Teeth affected Early eruptig teeth Late eruptig teeth After 8 years 2 No cosumers Before six years Betwee 6 to 8 years Cotrols

46 Table 5.13: Jowar cosumptio ad severity of detal fluorosis (scores of TFIdex) Age at which Jowar is cosumed Severity of detal fluorosis(scores of T ad F Idex) Cotrols before 6 yrs betwee 6 to 8 Yrs after 8 years Cases No Cosumers

47 Table 5.14: Geder ad Detal Fluorosis Cases Cotrols Odds ratio 95 CI Geder Male Female

48 Figure 5.12: Percetage distributio of study subjects with respect to TF scores ad Geder 167

49 Figure 5.13: Distributio of TF scores i percetage accordig to Geder i differet fluoride areas 168

50 Table 5.15: Age of study subjects ad detal fluorosis Age (i years) Cases Cotrols Odds ratio 95 CI

51 Table 5.16: Detal fluorosis ad fluoride cocetratio i drikig water Cases Cotrols Villages Odds ratio 95 CI Low fluoride area Medium fluoride area High fluoride area

52 Table 5.17: Detal fluorosis ad type of house roof of study subjects Type of Roof (SES marker) Cases Cotrols Odds ratio 95 CI Thatched Tiles Cemet

53 Table 5.18: Distributio of utritioal status (height for age) amog cases ad cotrols Cases Cotrols Nutritioal status HAZ* Normal Moderate Severe * Height for age 172

54 Table 5.19: Distributio of utritioal status (height for age) accordig to geder Males Females Normal Moderate Severe p=

55 Table 5.20: Distributio of utritioal status (height for age) accordig to age of subjects Normal Moderate Severe 12 years 13 years 14 years 15 years p=

56 Table5.21: Distributio of utritioal status (weight for age) amog cases ad cotrols Nutritioal Status WAZ* Cases Cotrols Normal Moderate Severe * Weight for age 175

57 Table 5.22: Distributio of utritioal status (weight for age) accordig to age of subjects 12 years 13 years 14 years 15 years Normal Moderate Severe p=

58 Table 5.23: Distributio of utritioal status (weight for age) accordig to geder Normal Moderate Severe Males Females p=

59 Table 5.24: Detal fluorosis ad dietary habits of study subjects Cases Dietary habit Cotrols Odds ratio 95 CI Vegetaria Mixed

60 Table 5.25: Frequecy of jowar cosumptio ad detal fluorosis Cases Daily cosumers 4 to 5 days i a week cosumers No cosumers Cotrols Odds ratio 95 C.I

61 Table 5.26: Age at which jowar was itroduced to child diet ad detal fluorosis Cases Cotrols Odds Ratio 95 C.I Jowar Cosumptio before 6 years of age betwee 6 to 8 years of age after 8 years No cosumers

62 Figure 5.14: Distributio of TF scores of study subjects accordig to the age where jowar was itroduced to child diet. 181

63 Table 5.27: Mea jowar cosumptio i grams amog cases ad cotrols Jowar cosumptio i grams Detal Fluorosis Number Mea* (gms) Std. Deviatio Std. Error Mea Cases Cotrols *p=

64 Table 5.28: Cosumptio of jowar i grams amog cases ad cotrols Cases Jowar cosumptio i gms Cotrols 0 gms Uto 95 gms to 205 gms to 300 gms gms ad above

65 Table 5.29: Mea jowar cosumptio amog jowar ad No jowar cosumers Mea daily cosumptio of Jowar i Grams Jowar Cosumptio Number Mea (gms) Std. Deviatio Std. Error Mea Yes No

66 Table 5.30: Stratificatio of detal fluorosis ad jowar cosumptio accordig to fluoride levels i drikig water Village Jowar cosumptio Yes Cases Cotrols Low fluoride Medium fluoride No Yes No Yes High fluoride No Stratifie d OR* 95 CI Matel-Haeszel Commo Odds Ratio Estimate 2.58 (OR 95 CI ) Crude Odds ratio of jowar cosumptio ad detal fluorosis 2.59 (95 CI 1.94 to 3.47) *Tests of Homogeeity of the Odds Ratio Brelow s test p=

67 Table 5.31: Stratificatio of detal fluorosis ad jowar cosumptio accordig to geder 95 CI Sex Jowar Cosumptio Cases Cotrols Odds ratio Yes Yes Low er Uppe r Males No Females No Matel-Haeszel Commo Odds Ratio Estimate 2.60 (95 CI ) Crude Odds ratio of jowar cosumptio ad detal fluorosis 2.59 (95 CI 1.94 to 3.47) Tests of Homogeeity of the Odds Ratio Brelow s test p=

68 Table 5.32: Multivariate Aalysis - Stepwise Method Variables Referece P value Odds Ratio Jowar Cosumptio Males Age (12 years) No Cosumers # Females Age(15 years) # # # # # # Normal # Normal # Normal # Normal # No Jowar Cosumers No Jowar Cosumers No Jowar Cosumers No Jowar Cosumers # # # # No Jowar Cosumers # Age (13 years) Age(14 years) Vegetaria Type of Roof (Cemet) High fluoride village Medium fluoride village Tea cosumptio Nutritioal status Malourished Moderate WAZ$ Severe malourished WAZ$ Moderate HAZ* Malourished Severe malourished HAZ* Daily Jowar cosumers Weekly Jowar cosumers Jowar cosumptio before 6 years of age Jowar cosumptio betwee 6 to 8 years of age Jowar cosumptio after 8 years Mixed Dietary habit Type of roof (Thatched) Low Fluoride Village Low Fluoride Village No Tea Cosumers 95 cofidece iterval Lower limit Upper limit 187

69 #adjusted for Village, Sex, Age, Tea Cosumptio, Occupatio of Father, Educatio of Mother, Dietary Habit, Malutritio Status, type of roof ad Jowar Cosumptio. $WAZ - weight for age Z scores, * HAZ - height for age Z scores Variables Age, Tea Cosumptio utritioal status, Occupatio of Father (SES), Educatio of mother (SES) did ot ay sigificat effect o Jowar cosumptio i the model. 188

70 5 4 3 Deviace Square Predicted probability Figure 5.15: Graph showig the goodess of fit model of multivariate aalysis Deviace square agaist Predicted probability 189

71 10 Stadard Probability Square Predicted probability Figure 5.16: Graph showig the goodess of fit model of multivariate aalysis Stadard Probability Square agaist Predicted probability 190

72 Table 5.33: Mea uriary fluoride level of study subjects at differet levels of fluoride cocetratio i drikig water Std. Error Miimum Maximum of (ppm) (ppm) Mea Village Mea (ppm) Std. Deviatio Low fluoride Medium fluoride High fluoride The Karl Pearso correlatio coefficiet r = 0.99 ad sigificat (p = 0.05). 191

73 Table 5.34: Mea uriary fluoride level i ppm amog jowar ad o jowar cosumers Uriary Fluoride level i ppm Jowar cosumptio Mea Std Std Error Mea Deviatio Mea Differece* Yes No *P = 0.018, idepedet samples T test, Equal variaces ot assumed. 192

74 Table 5.35: Mea uriary fluoride cocetratio accordig to jowar cosumptio at varyig levels of fluoride i drikig water Village Low fluoride Medium fluoride High fluoride 95 CI Mea Std. Mea Std. Error Differece Lower Upper (ppm) Deviatio Mea (ppm) (ppm) (ppm) Jowar cosumptio Yes No Yes No Yes No Yes No # # * #p=

75 Table 5.36: Comparisos of mea uriary fluoride level i ppm at fluoride levels i drikig water. Village F Sig. T Sig. (2tailed) Mea Differece (ppm) Std. Error Differece 95 CI Lower (ppm) Upper (ppm) Low fluoride Medium fluoride High fluoride

76 Figure 5.17: Mea uriary fluoride level accordig cosumptio of jowar i differet fluoride areas 195

77 Figure 5.18: Mea uriary fluoride level accordig to Severity of Detal Fluorosis (TF scores) i differet fluoride areas 196

78 Figure 5.19: Mea uriary fluoride level accordig to Severity of Detal Fluorosis (TF scores) ad age of the study subjects 197

79 Figure 5.20: Mea uriary fluoride level accordig to Severity of Detal Fluorosis (TF scores) ad geder 198