CDA Essentials 2018 • Volume 5 • Issue 1

S upporting Y our P ractice The following is based on an Applied Research article originally published on JCDA.ca —CDA’s online, open access scholarly publication that features articles indexed in Medline, Journal Citation Reports and Science Citation Index. Research Summary Fluoridation Exposure Status Based on Location of Data Collection in the CHMS: Is it Valid? Abstract Statistics Canada’s population health surveys may be an important source of up-to-date evidence on fluoridation and population oral health. The objective of this study was to examine the validity of a geographic measure of fluoridation from a national survey (based on site of data collection), by comparing it with estimates of fluoride level from urine samples. Fluoridation status based on data collection site seems crude, but is actually reasonably accurate compared with fluoride level in urine, in the context of a large national Canadian survey of urban and rural residents. Although findings are of limited use for individual-level risk assessment, they may be of interest to dental public health researchers and to those engaged in public health surveillance, because they inform efficient and readily available options for monitoring fluoridation status in populations. Since its initiation in 1945, community water fluoridation has been credited with contributing to significant improvements in population oral health, although the quality of many studies is modest. 1 Increasingly, the impact of fluoridation is difficult to assess because of the changing epidemiology of oral disease and the increasing availability of other sources of fluoride, such as toothpaste .2,3 It is important that evidence of the effect of fluoridation on population oral health be kept current, and population health surveys can be an important source of such information. An example is Statistics Canada’s Canadian Health Measures Survey (CHMS), which in 2007–2009 (Cycle 1) collected clinical oral health data from a population-based national sample. 4 In 2012, we published a study 5 on fluoridation and oral health using data from that survey and observed a significant association between fluoridation exposure and lower decayed, extracted/missing (due to caries) or filled teeth, either deciduous or permanent (deft/DMFT), adjusting for behavioural and sociodemographic variables. We also observed that the effect of fluoridation was strongest among income and education groups with the poorest oral health. In that study, our measure of fluoridation exposure was crude: “yes” or “no” based on location of data collection (survey respondents attended one of 15 data collection sites). Classification was based on information from various Internet sources about the current and historical fluoridation status of the location. Although crude, this was the only option available for that survey at the time, and it had some face validity: the main effects of fluoridation were stronger among those who reported usually drinking tap water and having lived in their current home for at least 2 years, which would be expected if we were capturing true fluoridation exposure status to at least some extent. 5 Lindsay McLaren PhD This article has been condensed and edited. The views expressed are those of the author and do not necessarily reflect the opinions or official policies of the Canadian Dental Association. lmclaren@ ucalgary.ca Full article available at jcda.ca/g 17 More Online 33 Issue 1 | 2018 | Dr. McLaren is associate professor, Department of Community Health Sciences, University of Calgary, Calgary, Alberta.