Bottled Water Use and Associations with Permanent Tooth Dental Caries Steven M. Levy Barbara Broffitt John J. Warren 2005 NAPCRG Annual Meeting The University of Iowa, Iowa City, IA 52242 Supported in part by grants 2RO1-DE09551, 2P30-DE10126, and M01-RR00059

Background Dental caries rates have declined substantially among children and young adults. Major factor is widespread exposure to caries-preventive benefits of fluoride.

Background Benefits of water fluoridation have consistently been reaffirmed. CDC and numerous scientific, professional, and other government agencies support water fluoridation. Water fluoridation is one of the 10 most important public health achievements of the 20th century (MMWR, CDC, 1999).

Background Bottled water has become an important alternative to public water systems Public’s concern about safety (contamination vs. purity) In fact, bottled water is not necessarily safer or better.

Background Bottled waters generally do not have to list fluoride levels Most, but not all, bottled waters are low in fluoride content. Our previous study found about 85% of bottled waters were low in fluoride.

Selected Bottled Water Fluoride Levels Brand F Level (ppm) Aquafina 0.05 Buffalo Don’s 0.15 Crystal Clear 0.02 Culligan 0.07 Dasani 0.14 Evian Hinckley & Schmitt Hinckley & Schmitt Nursery F 1.04 Humboldt Springs 1.02 Ice Mountain 0.04 Poland Spring

Background Few studies have detailed bottled water usage among young children. It is hypothesized that use of low fluoride bottled water is associated with higher dental caries rates. However, no studies have been published on this. We reported on the relationships between age 5 primary tooth dental caries and bottled water use at the 2003 NAPCRG Meeting.

Purpose To assess the relationships between bottled water use and age 9 dental caries experience.

Methods Newborns were recruited from eight Iowa hospitals into the longitudinal “Iowa Fluoride Study” in 1992-95. Data on water sources, use of dietary fluoride supplements, and use of fluoride toothpaste were collected by questionnaire several times per year.

Methods Detailed questions on water sources: Home, child care, school Bottled, including brands Filtered Asked if child consumed mostly tap, mostly bottled, or about half of each

Dental Exams Trained and calibrated dental examiners Dental caries assessed at both the cavitated and pre-cavitated (no cavity) levels. Primary tooth exams at ~age 5 (mean = 5.1 years). Mixed dentition exams at ~age 9 (mean = 9.2 years) of early-erupting permanent teeth and remaining primary 2nd molars.

Statistical Analyses Descriptive statistics Cochran-Mantel-Haenszel stratified analyses by age

Dependent Variables Permanent caries prevalence (12 teeth) Primary 2nd molar caries increment (4 teeth) Net Adjusted (for reversal rate by Beck method) Total caries increment (4 primary 2nd molars and 12 permanent teeth)

Overall Bottled Water Usage (%) Age (Months) 60 72 84 96 Mostly or About Half Bottled 7 9 10 Mostly Tap 93 91 90

Overall Caries Prevalence (Age 9) Variable (Caries Type) % Any Mean Maximum SD Precavitated (D1) 23 0.42 7 0.99 Cavitated (D2) 8 0.12 5 0.45 Filled (f) 14 0.32 26 1.48 D1D2 27 0.54 1.16 D1D2F 35 0.84 1.88 D2F 20 0.43 1.54

Adjusted Caries Increment Variable % Any Mean Maximum SD 1° 2nd Molars 31 0.91 11 1.82 1° 2nd Molars and Permanent 42 1.35 32 2.64

Age ~9 Permanent Tooth Caries -Prevalence Rate (on 12 Teeth) Dental Caries Prevalence By Bottled Water Use Age (months) Yes No Cochran-Mantel-Haentzel Chi-square p-value 60 20.4 21.0 0.47 72 22.3 20.1 0.61 84 28.9 19.7 0.22 96 25.9 17.6 0.20

Primary Second Molar Caries - Incidence Rate (on 4 Teeth) Adjusted Dental Caries Incidence By Bottled Water Use Age (months) Yes No Cochran-Mantel-Haentzel Chi-square p-value 60 40.1 30.9 0.65 72 25.5 31.6 0.55 84 24.1 33.2 0.24 96 31.8 29.7 0.69

Combined Primary Second Molar and Permanent Tooth Caries - Incidence Rate (on 16 Teeth) Adjusted Dental Caries Increment By Bottled Water Use Age (months) Yes No Cochran-Mantel-Haentzel Chi-square p-value 60 52.0 42.5 0.51 72 41.0 42.0 0.96 84 44.9 43.1 0.94 96 48.1 38.6 0.11

Similar patterns and no statistically significant differences looking at distributions of dental caries outcomes (Wilcoxon tests).

Bottled Water vs. Tap Water No significant differences in caries experience by bottled water use. When considering bottled water use near the time of exam (96 months), those using bottled water tended to have greater prevalence and incidence of cavitated decay experience than those using mostly tap water, Significant finding for 96-month bottled water use reported in abstract was prior to limiting analyses to the 16 teeth (allowed variable number of teeth at risk).

Limitations Small sample size with bottled water use. Repeated analyses with cross-sectional water source information – does not constitute comprehensive analyses of exposures over time. No statistically significant differences.

Future Directions Consideration of longitudinal patterns of use of bottled water. Consideration of actual amounts of water ingested. Adjustment for diet (especially soda pop consumption). Adjustment for other factors: toothbrushing, fluoride dentifrice use, SES, and other factors.

Conclusions Bottled waters generally low in fluoride No significant differences in age 9 caries experience or age 5 to 9 incidence by bottled water status. Data suggest use of substantial bottled water (~half or mostly bottled) close to the examination time could be associated with higher dental caries experience at age 9.

Methods (Extra) Fluoride levels of public water sources provided by state health department monthly reports. Bottled waters used by our children were assayed for fluoride content with standardized procedures using ion-selective fluoride electrodes. Well water sources and individually filtered public water sources also specifically assayed.