2012 vol. 36 no. 4 AUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH 393© 2012 The Authors. ANZJPH © 2012 Public Health Association of Australia

Letters

References1. Oakes JM, et al. Recruiting participants for neighborhood effects research:

strategies and outcomes of the Twin Cities Walking Study. Environ Behav. 2009;41(6):787-805.

2. Cook D. Consultation, for a Change? Engaging Users and Communities in the Policy Process. Soc Policy Adm. 2002;36(5):516-31.

3. Jones T, Newburn T. Widening Access: Improving Police Relations with Hard to Reach Groups. London (UK): Home Office Policing and Reducing Crime Unit; 2001.

4. Duncan DV, John BW, Thomas N. Using Internet-based surveys to reach hidden populations: Case of non abusive illicit drug users. Am J Health Behav. 2003;27(3):208-18.

5. Carpiano RM. Come take a walk with me: The “Go-Along” interview as a novel method for studying the implications of place for health and well-being. Health Place. 2009;15(1):263-72.

6. Ezzy D. Qualitative Analysis: Practice and Innovation. Sydeny (AUST): Allen and Unwin; 2002.

7. Hansen KM. The Effects of Incentives, Interview Length, and Interviewer Characteristics on Response Rates in a CATI-Study. Int J Public Opin Res. 2007;19(1):112-21.

Correspondence to: Kathryn Browne-Yung, Southgate Institute for Health, Society and Equity, Health Sciences Building, Flinders University, GPO Box 2100, SA 5001; e-mail: kathryn.browneyung@flinders.edu.au

doi: 10.1111/j.1753-6405.2012.00899.x

Use of GIS to allocate water fluoridation status in the NSW Teen Dental Survey 2010John Skinner

Centre for Oral Health Strategy, New South Wales

It is New South Wales (NSW) Government policy to fluoridate public water supplies of towns with a population of 1,000 or more people.1 The population coverage in NSW was 94% in June 2010, which was above the national coverage of 89%.2

Neil states that there are two main factors affecting the increased water fluoridation coverage in Australia – connection to a reticulated water supply and funding for the construction of new water fluoridation plants. In NSW, a third factor of support from local government is important, as the responsibility for the decision to commence water fluoridation in NSW primarily rests with local councils.3 Since 2004, the NSW Ministry of Health has proactively sought council support to implement water fluoridation in communities with a population of more than 1,000 people. Capital funding of $18 million is available for this purpose between 2007/08 and 2014/15.4

As water fluoridation is a major public health measure aimed at preventing dental caries, most oral health surveys look at the fluoridation status of participants and examine the strength of the preventive benefit to various populations of interest. In the NSW Teen Dental Survey 2010 the fluoridation status and fluoride

exposure history of participants was not directly collected in the student and parent questionnaires associated with the survey. Thus it was important to accurately infer this from the town or suburb and postcode of residence of each participant in the survey by geocoding a de-identified data set.

The Centre for Oral Health Strategy NSW keeps a database of fluoridated local council areas to monitor progress towards a target of 98% coverage by 20151 and these data were mapped in MapInfo 115 (Figure 1). SAS 9.26 was used to update the NSW Teen Dental Survey 2010 clinical dataset to add a fluoridation status variable for each student. These data were then used to compare dental disease rates for 14 and 15 year olds between fluoridated and non-fluoridated parts of available for this purpose. The finding was that there was a statistically significant association between higher rates of dental disease experience and living in a non-fluoridated area (Table 1).

This finding highlights both the continued importance of water fluoridation to reduce dental disease experience and the usefulness of GIS methods to add value to epidemiological data sets quickly and accurately.

References1. Centre for Oral Health Strategy. NSW Oral Health Strategic Directions 2011

– 2020 [Internet]. North Sydney (AUST): New South Wales Department of Health; 2010 [cited 2011 May 6]. Available from: http://www.health.nsw.gov.au/resources/pdf/oral_health_strategic_dir.pdf

2. Neil A. The extent of water fluoridation coverage in Australia. Aust N Z J Public Health. 2011;35(4) 392-3.

3. Fluoridation of Public Water Supplies Act 1957. NSW Government Gazette. 111:4359. 3 September 2010.

4. Centre for Oral Health Strategy. NSW Fluoridation Project Business Case [Internet]. Sydney (AUST): New South Wales Department of Health; 2006 [cited 2011 Oct 25]. Available from; http://www.health.nsw.gov.au/resources/cohs/Fluoridation_Project_Business_Case_v2_0_pdf

5. MapInfo Professional: desktop mapping software [computer software]. Version 11. Troy (NY): Pitney Bowes Software Inc; 2011.

6. SAS: statistical software [computer software]. Version 9.2. Cary (NC): SAS Institute; 2008.

Correspondence to: John Skinner, Centre for Oral Health Strategy NSW, 1 Mons Road, Westmead, NSW 2145; e-mail: john_skinner@wsahs.nsw.gov.au

Table 1: Decay experience, by fluoridation status of place of residence, NSW Teen Dental Survey 2010.

Decay Experience

No Decay Experience

Total

Un-Fluoridated 155 (62.3%) 94 (37.8%) 249

Fluoridated 431 (42.8%) 576 (57.2%) 1007

Total 586 670 1256

Figure 1: Fluoridated and Non-Fluoridated LGAs in NSW, May 2011.