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 and Doorslaer’s transformed Concentration Index; Receiver Operator Curve and Population Attributable Risk (PAR). Additional tests used were plots of SIC deciles (SIC10) and a Scottish Caries Inequality Metric (SCIM10). 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, SIC10 and SCIM10) 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

Efficient Algorithm on a Non-staggered Mesh for Simulating Rayleigh-Benard Convection in a Box

An efficient semi-implicit second-order-accurate finite-difference method is described for studying incompressible Rayleigh-Benard convection in a box, with sidewalls that are periodic, thermally insulated, or thermally conducting. Operator-splitting and a projection method reduce the algorithm at each time step to the solution of four Helmholtz equations and one Poisson equation, and these are are solved by fast direct methods. The method is numerically stable even though all field values are placed on a single non-staggered mesh commensurate with the boundaries. The efficiency and accuracy of the method are characterized for several representative convection problems.Comment: REVTeX, 30 pages, 5 figure

Toward catchment hydro-biogeochemical theories

Headwater catchments are the fundamental units that connect the land to the ocean. Hydrological flow and biogeochemical processes are intricately coupled, yet their respective sciences have progressed without much integration. Reaction kinetic theories that prescribe rate dependence on environmental variables (e.g., temperature and water content) have advanced substantially, mostly in well-mixed reactors, columns, and warming experiments without considering the characteristics of hydrological flow at the catchment scale. These theories have shown significant divergence from observations in natural systems. On the other hand, hydrological theories, including transit time theory, have progressed substantially yet have not been incorporated into understanding reactions at the catchment scale. Here we advocate for the development of integrated hydro-biogeochemical theories across gradients of climate, vegetation, and geology conditions. The lack of such theories presents barriers for understanding mechanisms and forecasting the future of the Critical Zone under human- and climate-induced perturbations. Although integration has started and co-located measurements are well under way, tremendous challenges remain. In particular, even in this era of "big data," we are still limited by data and will need to (1) intensify measurements beyond river channels and characterize the vertical connectivity and broadly the shallow and deep subsurface; (2) expand to older water dating beyond the time scales reflected in stable water isotopes; (3) combine the use of reactive solutes, nonreactive tracers, and isotopes; and (4) augment measurements in environments that are undergoing rapid changes. To develop integrated theories, it is essential to (1) engage models at all stages to develop model-informed data collection strategies and to maximize data usage; (2) adopt a "simple but not simplistic," or fit-for-purpose approach to include essential processes in process-based models; (3) blend the use of process-based and data-driven models in the framework of "theory-guided data science." Within the framework of hypothesis testing, model-data fusion can advance integrated theories that mechanistically link catchments' internal structures and external drivers to their functioning. It can not only advance the field of hydro-biogeochemistry, but also enable hind- and fore-casting and serve the society at large. Broadly, future education will need to cultivate thinkers at the intersections of traditional disciplines with hollistic approaches for understanding interacting processes in complex earth systems.This article is categorized under:Science of Water > Method

The vicious cycle of dental fear: exploring the interplay between oral health, service utilization and dental fear

BACKGROUND: Based on the hypothesis that a vicious cycle of dental fear exists, whereby the consequences of fear tend to maintain that fear, the relationship between dental fear, self-reported oral health status and the use of dental services was explored. METHODS: The study used a telephone interview survey with interviews predominantly conducted in 2002. A random sample of 6,112 Australian residents aged 16 years and over was selected from 13 strata across all States and Territories. Data were weighted across strata and by age and sex to obtain unbiased population estimates. RESULTS: People with higher dental fear visited the dentist less often and indicated a longer expected time before visiting a dentist in the future. Higher dental fear was associated with greater perceived need for dental treatment, increased social impact of oral ill-health and worse self-rated oral health. Visiting patterns associated with higher dental fear were more likely to be symptom driven with dental visits more likely to be for a problem or for the relief of pain. All the relationships assumed by a vicious cycle of dental fear were significant. In all, 29.2% of people who were very afraid of going to the dentist had delayed dental visiting, poor oral health and symptom-driven treatment seeking compared to 11.6% of people with no dental fear. CONCLUSION: Results are consistent with a hypothesised vicious cycle of dental fear whereby people with high dental fear are more likely to delay treatment, leading to more extensive dental problems and symptomatic visiting patterns which feed back into the maintenance or exacerbation of existing dental fear

Dental anxiety and dental attendance among 25-year-olds in Norway: time trends from 1997 to 2007

<p>Abstract</p> <p>Background</p> <p>So far, there are few studies considering the development of dental anxiety and dental attendance patterns across time in the general population of Norwegian adults. This study aimed to 1) determine the frequency of dental anxiety and regular dental attendance among 25-year-olds in Norway in 1997 and 2007, 2) to study the development (time trend) of dental anxiety and the socio-behavioral distribution of dental anxiety from 1997 to 2007.</p> <p>Method</p> <p>Random samples of 1,190 and 8,000 25-yr-olds were drawn from the populations of three counties in Western Norway in 1997 and 2007, respectively. The eligible participants received questionnaires by mail including questions on socio-demographics, dental anxiety (DAS) and dental attendance.</p> <p>Results</p> <p>In 1997, 11.5% males versus 23% females reported high dental anxiety (DAS ≥ 13). Corresponding figures in 2007 were 11.3% and 19.8%. The proportions who had attended yearly for a dental check-up during the past 5 years fell from 62% in 1997 (men 56.9% and women 66.4%) to 44.6% (men 38.1% and women 48.6%) in 2007. After controlling for potential confounding factors, the 25-year-olds were 1.4 times more likely to report dental anxiety in 1997 compared to 2007. The decrease was largely attributable to a lower mean DAS score among higher educated females in 2007 than in 1997. The discrepancy in dental anxiety between regular and non-regular dental attendees had decreased, largely attributable to a decline in dental anxiety among irregular dental attendees.</p> <p>Conclusion</p> <p>The study showed reduced dental anxiety and dental attendance among 25 year-olds in Norway from 1997 to 2007. This study points to the importance of controlling for possible changes in socio-demographic distributions when different cohorts are compared.</p

Dental general anaesthetic receipt among Australians aged 15+ years, 1998–1999 to 2004–2005

Background Adults receive dental general anaesthetic (DGA) care when standard dental treatment is not possible. Receipt of DGA care is resource-intensive and not without risk. This study explores DGA receipt among 15+-year-old Australians by a range of risk indicators. Methods DGA data were obtained from Australia's Hospital Morbidity Database from 1998–1999 to 2004–2005. Poisson regression modeling was used to examine DGA rates in relation to age, sex, Indigenous status, location and procedure. Results The overall DGA rate was 472.79 per 100,000 (95% CI 471.50–474.09). Treatment of impacted teeth (63.7%) was the most common reason for DGA receipt, followed by dental caries treatment (12.4%), although marked variations were seen by age-group. After adjusting for other covariates, DGA rates among 15–19-year-olds were 13.20 (95% CI 12.65–13.78) times higher than their 85+-year-old counterparts. Females had 1.46 (95% CI 1.45–1.47) times the rate of their male counterparts, while those living in rural/remote areas had 2.70 (95% CI 2.68–2.72) times the rate of metropolitan-dwellers. DGA rates for non-Indigenous persons were 4.88 (95% CI 4.73–5.03) times those of Indigenous persons. The DGA rate for 1+ extractions was 461.9 per 100,000 (95% CI 460.6–463.2), compared with a rate of 23.6 per 100,000 (95% CI 23.3–23.9) for 1+ restorations. Conclusion Nearly two-thirds of DGAs were for treatment of impacted teeth. Persons aged 15–19 years were disproportionately represented among those receiving DGA care, along with females, rural/remote-dwellers and those identifying as non-Indigenous. More research is required to better understand the public health implications of DGA care among 15+-year-olds, and how the demand for receipt of such care might be reduced.Lisa M Jamieson and Kaye F Roberts-Thomso

Additional psychometric data for the Spanish Modified Dental Anxiety Scale, and psychometric data for a Spanish version of the Revised Dental Beliefs Survey

<p>Abstract</p> <p>Background</p> <p>Hispanics comprise the largest ethnic minority group in the United States. Previous work with the Spanish Modified Dental Anxiety Scale (MDAS) yielded good validity, but lower test-retest reliability. We report the performance of the Spanish MDAS in a new sample, as well as the performance of the Spanish Revised Dental Beliefs Survey (R-DBS).</p> <p>Methods</p> <p>One hundred sixty two Spanish-speaking adults attending Spanish-language church services or an Hispanic cultural festival completed questionnaires containing the Spanish MDAS, Spanish R-DBS, and dental attendance questions, and underwent a brief oral examination. Church attendees completed the questionnaire a second time, for test-retest purposes.</p> <p>Results</p> <p>The Spanish MDAS and R-DBS were completed by 156 and 136 adults, respectively. The test-retest reliability of the Spanish MDAS was 0.83 (95% CI = 0.60-0.92). The internal reliability of the Spanish R-DBS was 0.96 (95% CI = 0.94-0.97), and the test-retest reliability was 0.86 (95% CI = 0.64-0.94). The two measures were significantly correlated (Spearman's rho = 0.38, p < 0.001). Participants who do not currently go to a dentist had significantly higher MDAS scores (t = 3.40, df = 106, p = 0.003) as well as significantly higher R-DBS scores (t = 2.21, df = 131, p = 0.029). Participants whose most recent dental visit was for pain or a problem, rather than for a check-up, scored significantly higher on both the MDAS (t = 3.00, df = 106, p = 0.003) and the R-DBS (t = 2.85, df = 92, p = 0.005). Those with high dental fear (MDAS score 19 or greater) were significantly more likely to have severe caries (Chi square = 6.644, df = 2, p = 0.036). Higher scores on the R-DBS were significantly related to having more missing teeth (Spearman's rho = 0.23, p = 0.009).</p> <p>Conclusion</p> <p>In this sample, the test-retest reliability of the Spanish MDAS was higher. The significant relationships between dental attendance and questionnaire scores, as well as the difference in caries severity seen in those with high fear, add to the evidence of this scale's construct validity in Hispanic samples. Our results also provide evidence for the internal and test-retest reliabilities, as well as the construct validity, of the Spanish R-DBS.</p

Lymphomas driven by Epstein-Barr virus nuclear antigen-1 (EBNA1) are dependant upon Mdm2

Epstein-Barr virus (EBV)-associated Burkitt's lymphoma is characterised by the deregulation of c-Myc expression and a restricted viral gene expression pattern in which the EBV nuclear antigen-1 (EBNA1) is the only viral protein to be consistently expressed. EBNA1 is required for viral genome propagation and segregation during latency. However, it has been much debated whether the protein plays a role in viral-associated tumourigenesis. We show that the lymphomas which arise in EµEBNA1 transgenic mice are unequivocally linked to EBNA1 expression and that both C-Myc and Mdm2 deregulation are central to this process. Tumour cell survival is supported by IL-2 and there is a skew towards CD8-positive T cells in the tumour environment, while the immune check-point protein PD-L1 is upregulated in the tumours. Additionally, several isoforms of Mdm2 are upregulated in the EµEBNA1 tumours, with increased phosphorylation at ser166, an expression pattern not seen in Eµc-Myc transgenic tumours. Concomitantly, E2F1, Xiap, Mta1, C-Fos and Stat1 are upregulated in the tumours. Using four independent inhibitors of Mdm2 we demonstrate that the EµEBNA1 tumour cells are dependant upon Mdm2 for survival (as they are upon c-Myc) and that Mdm2 inhibition is not accompanied by upregulation of p53, instead cell death is linked to loss of E2F1 expression, providing new insight into the underlying tumourigenic mechanism. This opens a new path to combat EBV-associated disease

Body mass index and dental caries in children and adolescents : a systematic review of literature published 2004 to 2011

The objectiveThe authors undertook an updated systematic review of the relationship between body mass index and dental caries in children and adolescents.MethodThe authors searched Medline, ISI, Cochrane, Scopus, Global Health and CINAHL databases and conducted lateral searches from reference lists for papers published from 2004 to 2011, inclusive. All empirical papers that tested associations between body mass index and dental caries in child and adolescent populations (aged 0 to 18 years) were included.ResultsDental caries is associated with both high and low body mass index.ConclusionA non-linear association between body mass index and dental caries may account for inconsistent findings in previous research. We recommend future research investigate the nature of the association between body mass index and dental caries in samples that include a full range of body mass index scores, and explore how factors such as socioeconomic status mediate the association between body mass index and dental caries.<br /

When public action undermines public health: A critical examination of antifluoridationist literature

Background: The addition of the chemical fluorine to the water supply, called water fluoridation, reduces dental caries by making teeth more resistant to demineralisation and more likely to remineralise when initially decayed. This process has been implemented in more than 30 countries around the world, is cost-effective and has been shown to be efficacious in preventing decay across a person's lifespan. However, attempts to expand this major public health achievement in line with Australia's National Oral Health Plan 2004–2013 are almost universally met with considerable resistance from opponents of water fluoridation, who engage in coordinated campaigns to portray water fluoridation as ineffective and highly dangerous. Discussion: Water fluoridation opponents employ multiple techniques to try and undermine the scientifically established effectiveness of water fluoridation. The materials they use are often based on Internet resources or published books that present a highly misleading picture of water fluoridation. These materials are used to sway public and political opinion to the detriment of public health. Despite an extensive body of literature, both studies and results within studies are often selectively reported, giving a biased portrayal of water fluoridation effectiveness. Positive findings are downplayed or trivialised and the population implications of these findings misinterpreted. Ecological comparisons are sometimes used to support spurious conclusions. Opponents of water fluoridation frequently repeat that water fluoridation is associated with adverse health effects and studies are selectively picked from the extensive literature to convey only claimed adverse findings related to water fluoridation. Techniques such as "the big lie" and innuendo are used to associate water fluoridation with health and environmental disasters, without factual support. Half-truths are presented, fallacious statements reiterated, and attempts are made to bamboozle the public with a large list of claims and quotes often with little scientific basis. Ultimately, attempts are made to discredit and slander scientists and various health organisations that support water fluoridation. Summary: Water fluoridation is an important public health initiative that has been found to be safe and effective. Nonetheless, the implementation of water fluoridation is still regularly interrupted by a relatively small group of individuals who use misinformation and rhetoric to induce doubts in the minds of the public and government officials. It is important that public health officials are aware of these tactics so that they can better counter their negative effectJason M Armfiel