Elimination of 'the Glasgow effect' in levels of dental caries in Scotland's five-year-old children: 10 cross-sectional surveys (1994-2012).

BACKGROUND: Socioeconomic inequalities in health within Glasgow, Scotland, are among the widest in the world. This is largely attributed to socio-economic conditions. The 'Glasgow Effect' labels the finding that the high prevalence of some diseases cannot be fully explained by a conventional area-based socio-economic metric. This study aimed to investigate whether differences in dental caries between Glasgow's resident children and those in the Rest of Scotland could be explained by this metric and whether differences were of fixed magnitude, over time. METHODS: Scotland's National Dental Inspection Programme (NDIP) cross-sectional data for five-year-old children in years: 1994, 1996, 1998, 2000, 2003, 2004, 2006, 2008, 2010, and 2012 (n = 92,564) were utilised. Endpoints were calculated from the mean decayed, missing and filled teeth score (d3mft) and percentage with obvious decay experience. Socioeconomic status was measured by DepCat, a Scottish area-based index. The Glasgow Effect was estimated by the odds-ratio (OR) of decay for Glasgow versus the Rest of Scotland adjusted by age, gender and DepCat. Inequalities were also assessed by the Significant Caries Index (SIC), SIC 10, and Scottish Caries Inequality Metric (SCIM 10). RESULTS: Decay levels for deprived Glasgow children have reduced to be similar to those in the Rest of Scotland. In 1993, OR for d3mft > 0 for those living in the Glasgow area was 1.34(1.10, 1.64), p = 0.005. This reduced below unity in 2012, OR = 0.85(0.77, 0.93), p < 0.001. There were downward trends (p < 0.001) in absolute inequality measured by SIC and SIC 10 in each of the geographic areas. The SCIM 10 demonstrated further reductions in inequality across the population. The downward trends for all the inequality measures were larger for Glasgow than the Rest of Scotland. CONCLUSIONS: Over the interval, Glasgow has eliminated the earlier extra health inequalities. When comparing 'like for like' by socioeconomic status there is now no higher level of dental caries in the Greater Glasgow area.

Comparison and relative utility of inequality measurements: as applied to Scotland's child dental health.

This study compared and assessed the utility of tests of inequality on a series of very large population caries datasets. National cross-sectional caries datasets for Scotland's 5-year-olds in 1993/94 (n = 5,078); 1995/96 (n = 6,240); 1997/98 (n = 6,584); 1999/00 (n = 6,781); 2002/03 (n = 9,747); 2003/04 (n = 10,956); 2005/06 (n = 10,945) and 2007/08 (n = 12,067) were obtained. Outcomes were based on the d3mft metric (i.e. the number of decayed, missing and filled teeth). An area-based deprivation category (DepCat) measured the subjects' socioeconomic status (SES). Simple absolute and relative inequality, Odds Ratios and the Significant Caries Index (SIC) as advocated by the World Health Organization were calculated. The measures of complex inequality applied to data were: the Slope Index of Inequality (absolute) and a variety of relative inequality tests i.e. Gini coefficient; Relative Index of Inequality; concentration curve; Koolman & Doorslaer's transformed Concentration Index; Receiver Operator Curve and Population Attributable Risk (PAR). Additional tests used were plots of SIC deciles (SIC(10)) and a Scottish Caries Inequality Metric (SCIM(10)). Over the period, mean d3mft improved from 3.1(95%CI 3.0-3.2) to 1.9(95%CI 1.8-1.9) and d3mft = 0% from 41.1(95%CI 39.8-42.3) to 58.3(95%CI 57.8-59.7). Absolute simple and complex inequality decreased. Relative simple and complex inequality remained comparatively stable. Our results support the use of the SII and RII to measure complex absolute and relative SES inequalities alongside additional tests of complex relative inequality such as PAR and Koolman and Doorslaer's transformed CI. The latter two have clear interpretations which may influence policy makers. Specialised dental metrics (i.e. SIC, SIC(10) and SCIM(10)) permit the exploration of other important inequalities not determined by SES, and could be applied to many other types of disease where ranking of morbidity is possible e.g. obesity. More generally, the approaches described may be applied to study patterns of health inequality affecting worldwide populations.

Developing a new self-reported scale of oral health outcomes for 5-year-old children (SOHO-5).

BACKGROUND: Information on the impact of oral health on quality of life of children younger than 8 years is mostly based on parental reports, as methodological and conceptual challenges have hindered the development of relevant validated self-reported measures. This study aimed to develop and assess the reliability and validity of a new self-reported oral health related quality of life measure, the Scale of Oral Health Outcomes for 5-year-old children (SOHO-5), in the UK. METHODS: A cross-sectional study of two phases. First, consultation focus groups (CFGs) with parents of 5-year-olds and review by experts informed the development of the SOHO-5 questionnaire. The second phase assessed its reliability and validity on a sample of grade 1 (5-year-old) primary schoolchildren in the Greater Glasgow and Clyde area, Scotland. Data were linked to available clinical oral health information and analysis involved associations of SOHO-5 with subjective and clinical outcomes. RESULTS: CFGs identified eating, drinking, appearance, sleeping, smiling, and socialising as the key oral impacts at this age. 332 children participated in the main study and for 296 (55% girls, mean d3mft: 1.3) clinical data were available. Overall, 49.0% reported at least one oral impact on their daily life. The most prevalent impacts were difficulty eating (28.7%), difficulty sleeping (18.5%), avoiding smiling due to toothache (14.9%) and avoiding smiling due to appearance (12.5%). The questionnaire was quick to administer, with very good comprehension levels. Cronbach's alpha was 0.74 and item-total correlation coefficients ranged between 0.30 and 0.60, demonstrating the internal consistency of the new measure. For validity, SOHO-5 scores were significantly associated with different subjective oral health outcomes (current toothache, toothache lifetime experience, satisfaction with teeth, presence of oral cavities) and an aggregate measure of clinical and subjective oral health outcomes. The new measure also discriminated between different clinical groups in relation to active caries, pulp involvement, and dental sepsis. CONCLUSIONS: This is the first study to develop and validate a self-reported oral health related quality of life measure for 5-year-old children. Initial reliability and validity findings were very satisfactory. SOHO-5 can be a useful tool in clinical studies and public health programs.