Fractional urinary fluoride excretion and nail fluoride concentrations in normal, wasted and stunted 4-5 year-old children in Nepal.

INTRODUCTION: It has been suggested that undernourished children are more likely to develop dental fluorosis. We investigated the effects of nutritional status on systemic fluoride metabolism including the proportion of ingested fluoride excreted through urine (i.e. fractional urinary fluoride excretion - FUFE) and fluoride concentration in nail clippings in children, aged 4-5 years, in Nepal. METHODS: Nutritional status was evaluated using weight-for-age (wasting) and height-for-age (stunting) indices. Total daily fluoride intake (TDFI) was estimated from diet and toothpaste ingestion and 24 -h urine collected to assess daily urinary fluoride excretion (DUFE). FUFE was calculated by dividing DUFE by TDFI. Nail clippings (finger and toe) were collected and analysed for fluoride concentration. RESULTS: Of the 100 children who participated, 89 provided information to assess FUFE and 51 children provided nail samples. Overall, 86.5 % of the 89 children were wasted and 39.3 % were stunted. When the samples were pooled into binary (affected and non-affected) categories, mean TDFI and mean DUFE were statistically significantly higher in the 77 wasted children (57.7 and 29.7 µg/kgbw/d, respectively) than the 12 non-wasted children (39.4 and 17.0 µg/kgbw/d, respectively). TDFI and DUFE were also statistically significantly higher in the 35 stunted children (65.1 and 34.5 µg/kgbw/d, respectively) than in the 54 non-stunted children (48.8 and 23.7 µg/kgbw/d, respectively). However, mean FUFE was similar in all groups. There were no statistically significant differences in fluoride concentration of either fingernails or toenails among the different categories of wasting, while mean fingernail fluoride concentration was statistically significantly higher in stunted (5.4 µg/g) than in non-stunted children (3.5 µg/g). CONCLUSION: Our study found no significant effect of nutritional status on the proportion of ingested fluoride excreted in urine (and consequently the proportion retained in the body). These findings suggest that nutritional status may be less likely to be a main risk factor for the development of dental fluorosis than children's dietary habits or total fluoride intake.

Effect of altitude on urinary, plasma and nail fluoride levels in children and adults in Nepal.

INTRODUCTION: A greater prevalence of dental fluorosis has been reported in higher- versus lower-altitude communities. This study, for the first time, examined several aspects of fluoride metabolism in children, aged 4-5 years, and their parent, living at lower altitude (<78 m) and higher altitude (>1487) areas in Nepal. METHODS: The study assessed total daily fluoride intake (TDFI), 24 h urinary fluoride excretion (UFE), and fluoride concentrations of toe- and finger-nail (FCtoenail, FCfingernail) in children and parents as well as fluoride concentration of plasma (FCplasma) in parents. Fractional urinary fluoride excretion (FUFE) was calculated as the ratio between UFE and TDFI. FCtoenail, FCfingernail and FCplasma were normalised for TDFI by dividing the variables by TDFI and the ratio was reported as the percentage. RESULTS: In total, 89 children and 80 parents took part in the study: 42 children and 41 parents from the lower altitude area; 47 children and 39 parents from the higher altitude area. Fluoride concentration of drinking water was significantly (P < 0.001) higher at lower altitude (0.395 mg F/l) than at higher altitude (0.104 mg F/l). TDFI was significantly (p < 0.001) higher in both children and parents living in lower altitude than those living at higher altitude. There was a statistically significant (p = 0.044) difference in the mean FUFE of children living at lower altitude (53%) and higher altitude (46%). However, no significant difference in FUFE was found between parents living at lower altitude (47%) compared with higher altitude (41%). In both children and parents, no statistically significant differences in normalised FCtoenail, FCfingernail were found between the two altitude areas. However, normalised FCplasma was statistically significantly (P = 0.005) higher in parents living at higher altitude (0.15%) compared with those living at lower altitude (0.11%). CONCLUSION: The results suggest that higher altitude living results in decreased urinary fluoride excretion, and consequently increased fluoride retention in children for a given dose (amount) of fluoride.

Serological study of dengue virus infection in Terai region, Nepal.

A cross-sectional study was conducted to determine dengue virus IgM-positive rate in Terai region, Nepal from August to December 2007. Serum samples were collected from 183 symptomatic cases. The samples were examined for dengue virus specific IgM using particle agglutination test. Of 183 serum samples, 55 (30.0%) had positive for dengue IgM antibody. The positive rate was highest (50.0%) in Biratnagar, and lowest (19.6%) in Chitwan male to female ratio was 2:1 in IgM-positive populations. IgM-positive rate was 29.0% at ages 21-30, 25.4% at ages 11-20 and 23.6% at ages 0-10, but 10.9% at ages 31-40, and ages over 40. There was not significant association between occupation of the patients and positive rate among farmer, labour, service, business and student.