Overlap of Five Chronic Pain Conditions: Temporomandibular Disorders, Headache, Back Pain, Irritable Bowel Syndrome, and Fibromyalgia

AIMS

To assess cohort retention in the OPPERA project and to compare the degree of overlap between pairs of chronic overlapping pain conditions (COPCs) using a cross-sectional analysis of data from 655 adults who completed follow-up in the OPPERA study.

METHODS

Subjects were classified for the absence or presence of each of the five COPCs. The extent of overlap beyond chance was quantified using odds ratios, which were calculated using binary logistic regression models.

RESULTS

While overlap was the norm, its magnitude varied according to COPC: 51% of people with headache had one or more overlapping COPCs, and this proportion increased to 90% for people with fibromyalgia. The degree of overlap between pairs of COPCs also varied considerably, with odds ratios being greatest for associations between musculoskeletal conditions (fibromyalgia, temporomandibular disorders, and low back pain) and less pronounced for overlap involving headache or IBS. Furthermore, univariate associations between some pairs of COPCs were nullified after adjusting for other COPCs.

CONCLUSION

There was greater overlap between fibromyalgia and either temporomandibular disorders or low back pain than between other pairs of COPCs. While musculoskeletal conditions exhibited some features that could be explained by a single functional syndrome, headache and irritable bowel syndrome did not.

Attributes Germane to Temporomandibular Disorders and Their Associations with Five Chronic Overlapping Pain Conditions

AIMS

To investigate whether TMD-related characteristics are indeed specific to TMD or whether they are also associated with other chronic overlapping pain conditions (COPCs).

METHODS

In this cross-sectional study, 22 characteristics related broadly to TMD (eg, jaw kinesiophobia, overuse behaviors, and functional limitation) were measured in 178 painful TMD cases who were also classified according to four COPCs: headache, low back pain, irritable bowel syndrome, and fibromyalgia. Differences in mean subscale scores were compared according to individual chronic pain conditions and according to number of COPCs.

RESULTS

Headache, low back pain, irritable bowel syndrome, and fibromyalgia were each associated (P < .05) with higher values of at least one TMD-relevant characteristic. In the multivariable analysis, TMD was independently associated with 20 of the 22 characteristics (P < .01), and other COPCs were associated variably. A critical threshold existed between the number of COPCs and TMD characteristics: all characteristics were elevated for subjects with ≥ 3 COPCs (P ≤ .01).

CONCLUSION

The overlap between COPCs and characteristics typically regarded as specific to painful TMD has implications for treatment targeted at both the local TMD condition and the broader pain disorder underlying the COPC(s). In TMD patients, the overall burden of pain from COPCs may create a shift in the pain-processing systems that underlie these TMD-relevant characteristics.

Prenatal smoking and the risk of early childhood caries: A prospective cohort study

Introduction

Dental caries is a chronic complex disease of multifactorial etiology that affects a quarter of U.S. children. This study evaluated the association between prenatal smoking and offspring caries experience and used a negative control exposure analysis to assess if the association is causal.

Methods

Data from 1429 mother-offspring participants of the 1991/92 Avon Longitudinal Study of Parents and Children conducted in Bristol, England were analyzed. Prenatal smoking (yes v. no) and quantity smoked (none, <half pack, ≥half pack) were self-reported while offspring caries experience was determined by clinical oral examinations at 3 time points. Discrete time hazards regression estimated hazard odds of first occurrence of offspring caries, and substituted partner smoking for prenatal smoking in a negative control exposure analysis.

Results

Overall, 22% smoked during pregnancy while 36% of partners smoked. The adjusted hazard odds of first occurrence of caries experience in the offsprings of prenatal smokers compared to the offsprings of non-smokers was 1.42 (95% CI: 1.08, 1.86). Relative to non-smoking, smoking <half pack/day and ≥half pack/day during pregnancy were associated with higher adjusted hazard odds of offspring caries experience: 1.10 (95% CI: 0.79, 1.54) and 1.38 (0.98, 1.95) respectively. Partner smoking was associated with 33% (95% CI: 1.07, 1.65) higher adjusted hazard odds of first offspring caries experience occurrence.

Conclusions

Prenatal and partner smoking appear associated with greater offspring caries experience. The positive association with partner smoking suggests either a shared genetic predisposition or unmeasured common environmental factors with the mother as opposed to a direct biological effect of the intrauterine environment.

Denture wearing and mortality risk in edentulous American adults: A propensity score analysis

OBJECTIVE

To evaluate the association between complete denture use and subsequent mortality among edentulous adults.

METHODS

Data from 1649 edentulous adults who participated in the Third National Health and Nutritional Examination Survey were linked to public-use mortality files for the period up to December 2015. Denture wearing, defined as use of complete dentures in both arches (clinically inspected) all the time or only when awake, was compared to non-wearing, defined as use of dentures occasionally or not at all. The primary outcome was all-cause mortality. Data on 27 covariates, classified as sociodemographic characteristics, behavioral factors, health insurance, laboratory tests and general health status, were used to create propensity scores for weighted and matched analyses.

RESULTS

In weighted data, the difference in mortality rate between denture and non-denture wearers was 11.1 (95 %CI: 3.6-18.6) deaths per 1000 person-years and the number needed to treat (NNT) at 10 years was 12. Denture wearers had 15 % lower risk of death (HR: 0.85; 95 % CI: 0.73-0.98) than non-denture wearers. In the matched sample, the mortality rate difference between denture and non-denture wearers was 8.8 (95 %CI: 0.2-17.4) deaths per 1000 person-years and the NNT at 10 years was 11. Risk of death was 21 % lower among denture wearers (HR: 0.79; 95 % CI: 0.68, 0.92) than non-denture wearers.

CONCLUSION

This longitudinal analysis showed that the use of complete dentures was associated with longer survival and lower all-cause mortality risk among American edentulous adults. NNT is interpreted as one death prevented after 10 years for every twelve rehabilitated dentitions with removable complete dentures.

CLINICAL SIGNIFICANCE

Edentulous adults wearing complete dentures had longer survival and lower overall mortality risk than non-denture wearers, suggesting that prosthodontic rehabilitation with removable complete dentures might have benefits beyond restoring oral functioning.

Effect of Treatment Expectation on Placebo Response and Analgesic Efficacy: A Secondary Aim in a Randomized Clinical Trial

This randomized clinical trial assessed the effect of patients’ treatment expectations on the efficacy of propranolol vs placebo among patients with temporomandibular disorder–associated myalgia.

Associations of Psychologic Factors with Multiple Chronic Overlapping Pain Conditions

AIMS

To characterize psychologic functioning across five chronic overlapping pain conditions (COPCs)-temporomandibular disorders, fibromyalgia, low back pain, headache, and irritable bowel syndrome-and their overlaps.

METHODS

Participants were 655 adults in the OPPERA study. Psychologic variables were standardized in separate logistic regression models to compare their relative strength of association with each COPC. Random forest regression was used to explore the association of all psychologic measures with COPCs simultaneously. Linear regression analyses examined whether the count of COPCs was associated with psychologic measures.

RESULTS

In univariate and multivariable analyses, measures of somatic symptom burden showed the strongest associations with individual COPCs and with the number of COPCs. Additional psychologic variables that showed significant associations with individual COPCs and their overlap included negative mood, perceived stress, and pain catastrophizing.

CONCLUSION

These findings highlight the importance of psychologic functioning in the assessment and management of these overlapping pain conditions.

Clinical Characteristics of Pain Among Five Chronic Overlapping Pain Conditions

AIMS

To describe the pain characteristics of five index chronic overlapping pain conditions (COPCs) and to assess each COPC separately in order to determine whether the presence of comorbid COPCs is associated with bodily pain distribution, pain intensity, pain interference, and high-impact pain of the index COPC.

METHODS

Data were from a convenience sample of 655 US adults, of whom 388 had one or more of the five COPCs: painful temporomandibular disorders, headache, low back pain, irritable bowel syndrome, and/or fibromyalgia. Data were collected using pain location checklists and self-report questions regarding pain attributes. The contributions of the COPCs to reported pain intensity and interference were assessed using multivariable regression models.

RESULTS/CONCLUSION

Heat maps from a pain body manikin illustrated that very little of the body was pain free within these COPCs. All pain attributes were the most severe for fibromyalgia and the least severe for irritable bowel syndrome. Within each index COPC, pain intensity, pain interference, and the proportion of participants with high-impact pain increased with each additional comorbid COPC up to four or more COPCs (including the index COPC) (P < .01). High-impact pain associated with an index COPC was influenced by type and number of comorbid COPCs, largely in a gradient-specific manner.

Associations of Sleep Disturbance, Atopy, and Other Health Measures with Chronic Overlapping Pain Conditions

AIMS

To quantify the contributions of atopic disorders, sleep disturbance, and other health conditions to five common pain conditions.

METHODS

This cross-sectional analysis used data from 655 participants in the OPPERA study. The authors investigated the individual and collective associations of five chronic overlapping pain conditions (COPCs) with medically diagnosed atopic disorders and self-reported sleep disturbance, fatigue, and symptoms of obstructive sleep apnea. Atopic disorders were allergies, allergic rhinitis, atopic dermatitis, allergic asthma, urticaria, allergic conjunctivitis, and food allergy. Logistic regression models estimated odds ratios as measures of association with temporomandibular disorders, headache, irritable bowel syndrome, low back pain, and fibromyalgia. Measures of sleep and atopy disorders were standardized to z scores to determine the relative strength of their associations with each COPC. Sociodemographic characteristics and body mass index were covariates. Random forest regression analyzed all variables simultaneously, computing importance metrics to determine which variables best differentiated pain cases from controls.

RESULTS

Fatigue and sleep disturbance were strongly associated with each COPC and with the total number of COPCs. An increase of one standard deviation in fatigue or sleep disturbance score was associated with approximately two-fold greater odds of having a COPC. In random forest models, atopic disorders contributed more than other health measures to differentiating between cases and controls of headache, whereas other COPCs were best differentiated by measures of fatigue or sleep.

CONCLUSION

Atopic disorders, previously recognized as predictors of poor sleep, are associated with COPCs after accounting for sleep problems.

Emulation of Community Water Fluoridation Coverage Across US Counties

INTRODUCTION

Expansion of community water fluoridation has stalled in the United States, leaving 115 million Americans without fluoridated drinking water.

OBJECTIVE

This study used spatial regression methods to assess contributions of supply-side factors (neighboring counties' fluoridation coverage) and demand-side factors (health literacy, education, and population density of the local county) in predicting the extent of fluoridation in US counties.

METHODS

For this cross-sectional ecological analysis, data from the 2014 Water Fluoridation Reporting System for all 3,135 US counties were merged with sociodemographic data from the 2014 American Community Survey and county-level estimates of health literacy based on the National Association of Adult Literacy Survey. We employed multilevel geographically weighted autoregressive models to predict fluoridation coverage of each county as a function of fluoridation coverage of neighboring counties and local-county covariates: either health literacy or sociodemographic characteristics. Akaike's Information Criterion was used to distinguish the better model in terms of explanatory power and parsimony.

RESULTS

In the best-fit model, an increase from the first to third quartile of neighboring counties' fluoridation coverage was associated with an increase of 27.76 percentage points (95% confidence limits [CI] = 27.71, 27.81) in a local county's fluoridation coverage, while an increase from the first to third quartile of local county's health literacy was associated with an increase of 2.8 percentage points (95% CL = 2.68, 2.89). The results are consistent with a process of emulation, in which counties implement fluoridation based upon their population's health literacy and the extent of fluoridation practiced in neighboring counties.

CONCLUSION

These results suggest that demand for community water fluoridation will increase as health literacy increases within a county. Furthermore, when considering expansion of fluoridation, non-fluoridated communities can benefit from precedents from nearby communities that are fluoridated.

KNOWLEDGE TRANSFER STATEMENT

Expanded coverage of community water fluoridation has stalled in the United States. The economic theory of diffusion describes how, over time and space, policy enacted in one community can influence public opinion in a neighboring community. This study applies geospatial analysis of county-level data and the theory of policy diffusion to demonstrate that fluoridated counties can promote the implementation of community water fluoridation in their neighboring, non-fluoridated communities.

Periodontitis and prevalence of elevated aminotransferases in the Hispanic Community Health Study/Study of Latinos

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) prevalence is greater among Hispanics/Latinos than other racial/ethnic groups and prevalence is further reported to vary among Hispanic/Latino background groups. Experimental animal and human studies demonstrate associations between periodontitis and NAFLD, not yet reported among Hispanics/Latinos. This study examined periodontitis as a novel risk factor that may contribute to the burden of NAFLD among Hispanics/Latinos.

METHODS

Data came from 11,914 participants of the Hispanic Community Health Study/Study of Latinos. Periodontitis was defined as the extent (none, < 30%, ≥30%) of periodontal sites with clinical attachment level (CAL) of ≥3 mm or probing pocket depth (PD) of ≥4 mm. Elevated serum transaminases indicative of suspected NAFLD were defined as having alanine aminotransferase levels (ALT) > 40 IU/L or aspartate aminotransferase (AST) > 37 IU/L for men and ALT > 31 IU/L or AST > 31 IU/L for women. Survey-logistic regression models estimated prevalence odds ratios (POR) and 95% confidence intervals (CI) for the association between periodontitis and suspected NAFLD.

RESULTS

The overall age-standardized percentage of study participants with < 30% of sites with CAL ≥3 mm or PD ≥4 mm was 53.5% and 58.6%, respectively, while participants with ≥30% sites with CAL ≥3 mm or PD ≥4 mm comprised 16% and 5.72%, respectively. The overall age-standardized prevalence (95% CI) of suspected NAFLD was 18.1% (17.1-19.0). For the entire cohort, we observed a dose-response (i.e. graded) association between PD ≥4 mm and the prevalence odds of suspected NAFLD, whereby participants with < 30% affected had a crude POR = 1.19 (95% CI: 1.03, 1.38) while participants with ≥30% affected had a crude POR = 1.39 (95% CI: 1.02, 1.90). These crude estimates were attenuated toward the null and rendered non-significant upon covariate adjustment. No differences were found by Hispanic/Latino background group.

CONCLUSION

Previously reported associations between periodontitis and NAFLD were marginal to null in this study of a diverse group of Hispanics/Latinos.

Premorbid and concurrent predictors of TMD onset and persistence

BACKGROUND

Multiple risk factors predict temporomandibular disorders (TMD) onset, but temporal changes in risk factors and their contribution to risk of TMD have not been evaluated. The study aims were to (a) describe changes occurring in premorbid TMD risk factors when re-measured at TMD onset and 6 months later, and (b) determine if measures of change improve accuracy in predicting TMD incidence compared to premorbid measures alone.

METHODS

In this observational prospective cohort study at four university research clinics, 3,258 community-based, 18- to 44-year-olds without TMD were enrolled. During the 3-year median follow-up, 260 incident cases of first-onset TMD were identified, and 196 TMD-free subjects were selected as matched controls. Six-months later, 147 of 260 incident cases (56.6%) were re-examined revealing 72 (49%) with 'persistent TMD' and 75 (51%) whose condition had resolved ('transient TMD'). Virtually all (126) of the 127 re-examined controls remained without TMD. Questionnaires and clinical measurements evaluated risk factors from clinical, health, psychological and behavioural and neurosensory domains.

RESULTS

Most risk factors across all four domains increased with TMD onset, remained elevated in the persistent group and declined in the transient group (i.e., significant ANOVA interactions, p < .05). Accuracy in predicting first-onset TMD, quantified as area under the receiver operating characteristic curve was 0.71 (95% CL 0.68, 0.73) using only premorbid measures of risk factors, which increased to 0.91 (95% CL 0.89, 0.94) after addition of change measures.

CONCLUSIONS

TMD pain onset and persistence appear to be determined by enduring characteristics of the person as well as mutually interactive with temporally evolving variables.

SIGNIFICANCE

TMD is known to be a complex disorder, in which onset and persistence are associated with disease-related variables in multiple domains, including environmental exposure, clinical, psychological, health status, and pain processing variables. Using a more dynamic approach in order to capture change across time, many aspects of those domains were found to worsen prior to the reporting of pain, with bidirectional influences between domains and pain emergence likely. TMD onset appears to represent the cumulative effect of multiple system dysregulation.

A functional substitution in the L-aromatic amino acid decarboxylase enzyme worsens somatic symptoms via a serotonergic pathway

OBJECTIVE

Heightened somatic symptoms are reported by a wide range of patients with chronic pain and have been associated with emotional distress and physical dysfunction. Despite their clinical significance, molecular mechanisms leading to their manifestation are not understood.

METHODS

We used an association study design based on a curated list of 3,295 single nucleotide polymorphisms mapped to 358 genes to test somatic symptoms reporting using the Pennebaker Inventory of Limbic Languidness questionnaire from a case-control cohort of orofacial pain (n = 1,607). A replication meta-analysis of 3 independent cohorts (n = 3,189) was followed by functional validation, including in silico molecular dynamics, in vitro enzyme assays, and measures of serotonin (5-HT) plasma concentration.

RESULTS

An association with the T allele of rs11575542 coding for an arginine to glutamine substitution in the L-aromatic amino acid decarboxylase (AADC) enzyme was replicated in a meta-analysis of 3 independent cohorts. In a combined meta-analysis of all cohorts, this association reached p = 6.43 × 10^-8 . In silico studies demonstrated that this substitution dramatically reduces the conformational dynamics of AADC, potentially lowering its binding capacity to a cofactor. in vitro enzymatic assays showed that this substitution reduces the maximum kinetic velocity of AADC, hence lowering 5-HT levels. Finally, plasma samples from 90 subjects showed correlation between low 5-HT levels and heightened somatic symptoms.

INTERPRETATION

Using functional genomics approaches, we identified a polymorphism in the AADC enzyme that contributes to somatic symptoms through reduced levels of 5-HT. Our findings suggest a molecular mechanism underlying the pathophysiology of somatic symptoms and opens up new treatment options targeting the serotonergic system. ANN NEUROL 2019;86:168-180.

Anatomical selectivity in overlap of chronic facial and bodily pain

Supplemental Digital Content is Available in the Text.

Background:

Chronic facial pain often overlaps with pain experienced elsewhere in the body, although previous studies have focused on a few, selected pain conditions when assessing the degree of overlap.

Aim:

To quantify the degree of overlap between facial pain and pain reported at multiple locations throughout the body.

Methods:

Data were from a case–control study of US adults participating in the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) project. They were interviewed to determine the presence of chronic facial pain (n = 424 cases) or its absence (n = 912 controls). A mailed questionnaire with a body drawing asked about pain at other locations. Odds ratios (ORs) and 95% confidence limits (95% CLs) quantified the degree of overlap between facial pain and pain at other locations. For replication, cross-sectional data were analyzed from the UK Biobank study (n = 459,604 participants) and the US National Health Interview Survey (n = 27,731 participants).

Results:

In univariate analysis, facial pain had greatest overlap with headache (OR = 14.2, 95% CL = 9.7–20.8) followed by neck pain (OR = 8.5, 95% CL = 6.5–11.0), whereas overlap decreased substantially (ORs of 4.4 or less) for pain at successively remote locations below the neck. The same anatomically based ranking of ORs persisted in multivariable analysis that adjusted for demographics and risk factors for facial pain. Findings were replicated in the UK Biobank study and the US National Health Interview Survey. The observed anatomical selectivity in the degree of overlap could be a consequence of neurosensory and/or affective processes that differentially amplify pain according to its location.

Genome-wide association reveals contribution of MRAS to painful temporomandibular disorder in males

Painful temporomandibular disorders (TMDs) are the leading cause of chronic orofacial pain, but its underlying molecular mechanisms remain obscure. Although many environmental factors have been associated with higher risk of developing painful TMD, family and twin studies support a heritable genetic component as well. We performed a genome-wide association study assuming an additive genetic model of TMD in a discovery cohort of 999 cases and 2031 TMD-free controls from the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) study. Using logistic models adjusted for sex, age, enrollment site, and race, we identified 3 distinct loci that were significant in combined or sex-segregated analyses. A single-nucleotide polymorphism on chromosome 3 (rs13078961) was significantly associated with TMD in males only (odds ratio = 2.9, 95% confidence interval: 2.02-4.27, P = 2.2 × 10). This association was nominally replicated in a meta-analysis of 7 independent orofacial pain cohorts including 160,194 participants (odds ratio = 1.16, 95% confidence interval: 1.0-1.35, P = 2.3 × 10). Functional analysis in human dorsal root ganglia and blood indicated this variant is an expression quantitative trait locus, with the minor allele associated with decreased expression of the nearby muscle RAS oncogene homolog (MRAS) gene (beta = -0.51, P = 2.43 × 10). Male mice, but not female mice, with a null mutation of Mras displayed persistent mechanical allodynia in a model of inflammatory pain. Genetic and behavioral evidence support a novel mechanism by which genetically determined MRAS expression moderates the resiliency to chronic pain. This effect is male-specific and may contribute to the lower rates of painful TMD in men.

Association Between Water Fluoridation and Income-Related Dental Caries of US Children and Adolescents

This cohort study examines the incidence of dental caries in children and adolescents of varying income levels living in areas with vs without water fluoridation.

Referendum opposition to fluoridation and health literacy: a cross-sectional analysis conducted in three large US cities

OBJECTIVE

To explore health literacy as a marker of voter confusion in order to understand the basis for public opposition to community water fluoridation.

DESIGN

A cross-sectional study.

SETTING

Conducted in three large US cities of San Antonio, Texas (602 voting precincts); Wichita, Kansas (171 voting precincts); and Portland, Oregon (132 voting precincts). Precinct-level voting data were compiled from community water fluoridation referendums conducted in San Antonio in 2002, Wichita in 2012 and Portland in 2013.

PARTICIPANTS

Voter turnout expressed as a percentage of registered voters was 38% in San Antonio (n=2 92 811), 47% in Wichita (n=129 199) and 38% in Portland (n=164 301).

MAIN OUTCOME MEASURES

The dependent variable was the percentage of votes in favour of fluoridating drinking water. Precinct-level voting data were mapped to precinct scores of health literacy, and to US Census and American Community Survey characteristics of race/ethnicity, age, income and educational attainment. Multilevel regression with post-stratification predicted the precinct mean health literacy scores, with weights generated from the National Association of Adult Literacy health literacy survey, with item response theory computed scoring for health literacy. Predictive models on voter support of community water fluoridation were compared using robust linear regression to determine how precinct-level characteristics influenced voter support in order to determine whether health literacy explained more variance in voting preference than sociodemographic characteristics.

RESULTS

Precinct-level health literacy was positively associated with voter turnout, although sociodemographic characteristics were better predictors of turnout. Approximately 60% of voters opposed community water fluoridation in Wichita and Portland, whereas in San Antonio, a small majority (53%) voted in favour of it. Models suggest that a one SD increase in health literacy scores predicted a 12 percentage point increase support for community water fluoridation.

CONCLUSION

Educational attainment and health literacy are modifiable characteristics associated with voting precincts' support for community water fluoridation.

Measurement of Early Childhood Oral Health for Research Purposes: Dental Caries Experience and Developmental Defects of the Enamel in the Primary Dentition

Epidemiological investigations of early childhood oral health rely upon the collection of high-quality clinical measures of health and disease. However, ascertainment of valid and accurate clinical measures presents unique challenges among young, preschool-age children. The paper presents a clinical research protocol for the conduct of oral epidemiological examinations among children, implemented in ZOE 2.0, a large-scale population-based genetic epidemiologic study of early childhood caries (ECC). The protocol has been developed for the collection of information on tooth surface-level dental caries experience and tooth-level developmental defects of the enamel in the primary dentition. Dental caries experience is recorded using visual criteria modified from the International Caries Detection and Assessment System (ICDAS), and measurement of developmental defects is based upon the modified Clarkson and O'Mullane Developmental Defects of the Enamel Index. After a dental prophylaxis (toothbrushing among all children and flossing as needed), children's teeth are examined by trained and calibrated examiners in community locations, using portable dental equipment, compressed air, and uniform artificial light and magnification conditions. Data are entered directly onto a computer using a custom Microsoft Access-based data entry application. The ZOE 2.0 clinical protocol has been implemented successfully for the conduct of over 6000 research examinations to date, contributing phenotype data to downstream genomics and other "omics" studies of ECC and DDE, as well as traditional clinical and epidemiologic dental research.

Characteristics Associated With High-Impact Pain in People With Temporomandibular Disorder: A Cross-Sectional Study

High-impact (disabling) pain diminishes the quality of life and increases health care costs. The purpose of this study was to identify the variables that distinguish between high- and low-impact pain among individuals with painful temporomandibular disorder (TMD). Community-dwelling adults (N = 846) with chronic TMD completed standardized questionnaires that assessed the following: 1) sociodemographic characteristics, 2) psychological distress, 3) clinical pain, and 4) experimental pain. We used high-impact pain, classified using the Graded Chronic Pain Scale, as the dependent variable in logistic regression modeling to evaluate the contribution of variables from each domain. Cross-validated area under the receiver operating characteristic curve (AUC) quantified model discrimination. One-third of the participants had high-impact pain. Sociodemographic variables discriminated weakly between low- and high-impact pain (AUC = .61, 95% confidence interval [CI] = 0.57, 0.65), with the exception of race. An 18-variable model encompassing all 4 domains had good discrimination (AUC = 0.79, 95% CI = 0.75, 0.82), as did a simplified model (sociodemographic variables plus catastrophizing, jaw limitation, and number of painful body sites) (AUC = 0.79, 95% CI = 0.76, 0.82). Duration of pain, sex, and experimental pain testing results were not associated. The characteristics that discriminated most effectively between people with low- and high-impact TMD pain included clinical pain features and the ability to cope with pain. PERSPECTIVE: This article presents the results of a multivariable model designed to discriminate between people with high- and low-impact pain in a community-based sample of people with painful chronic TMD. The findings emphasize the importance of catastrophizing, jaw limitation, and painful body sites associated with pain-related impact.

Long-chain omega-3 fatty acids and headache in the U.S. population

The objective of this study was to assess whether dietary intake of long-chain omega-3 polyunsaturated fatty acids (PUFAs) is associated with lower prevalence of headache in the U.S.

POPULATION

This cross-sectional study used data for a nationally representative sample of 12,317 men and women aged ≥ 20 years participating in the National Health and Nutrition Examination Surveys of 1999-2004. Interviewers recorded self-report of severe headache or migraine in the past three months. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were quantified from 24-hour dietary recall using the U.S. Department of Agriculture National Nutrient Database. Serum concentration of C-reactive protein, a marker of inflammation and potential mediator of PUFA's analgesic properties, was quantified by latex-enhanced nephelometry. Multivariable generalized linear models estimated prevalence ratios (PR) with 95% confidence limits (CL) for severe headache or migraine adjusting for NHANES cycle, sociodemographic characteristics, body mass index and total energy intake. The unadjusted prevalence of severe headache or migraine was 22.0% (females 28.2%, males 15.5%). In multivariable analysis, greater intake of omega-3 PUFAs was associated with lower prevalence of severe headache or migraine: PR 0.94 (95% CL: 0.88, 0.99, p = 0.035) per log unit increase in EPA, and PR 0.94 (95% CL: 0.90, 0.99, p = 0.023) per log unit increase in DHA. The strength of association was greater for non-Mexican Hispanics than for other racial/ethnic groups but was not attenuated after adjustment for C-reactive protein. In conclusion, higher dietary intakes of EPA and DHA were associated with lower prevalence of headache supporting the hypothesis that omega-3 PUFAs may prevent or reduce headache.

Water Fluoridation and Dental Caries in U.S. Children and Adolescents

Fluoridation of America's drinking water was among the great public health achievements of the 20th century. Yet there is a paucity of studies from the past 3 decades investigating its dental health benefits in the U.S.

POPULATION

This cross-sectional study sought to evaluate associations between availability of community water fluoridation (CWF) and dental caries experience in the U.S. child and adolescent population. County-level estimates of the percentage of population served by CWF (% CWF) from the Centers for Disease Control and Prevention's Water Fluoridation Reporting System were merged with dental examination data from 10 y of National Health and Nutrition Examination Surveys (1999 to 2004 and 2011 to 2014). Dental caries experience in the primary dentition (decayed and filled tooth surfaces [dfs]) was calculated for 7,000 children aged 2 to 8 y and in the permanent dentition (decayed, missing, and filled tooth surfaces [DMFS]) for 12,604 children and adolescents aged 6 to 17 y. Linear regression models estimated associations between % CWF and dental caries experience with adjustment for sociodemographic characteristics: age, sex, race/ethnicity, rural-urban location, head-of-household education, and period since last dental visit. Sensitivity analysis excluded counties fluoridated after 1998. In unadjusted analysis, caries experience in the primary dentition was lower in counties with ≥75% CWF (mean dfs = 3.3; 95% confidence limit [CL] = 2.8, 3.7) than in counties with <75% CWF (mean dfs = 4.6; 95% CL = 3.9, 5.4), a prevented fraction of 30% (95% CL = 11, 48). The difference was also statistically significant, although less pronounced, in the permanent dentition: mean DMFS (95% CL) was 2.2 (2.0, 2.4) and 1.9 (1.8, 2.1), respectively, representing a prevented fraction of 12% (95% CL = 1, 23). Statistically significant associations likewise were seen when % CWF was modeled as a continuum, and differences tended to increase in covariate-adjusted analysis and in sensitivity analysis. These findings confirm a substantial caries-preventive benefit of CWF for U.S. children and that the benefit is most pronounced in primary teeth.

Fluoridation advocacy in referenda where media coverage is balanced yet biased

BACKGROUND

Despite supporting scientific evidence, community water fluoridation (CWF) often fails in public referenda. To understand why, the authors quantitatively analyzed text from news media coverage of CWF referenda.

METHODS

The authors analyzed text from 234 articles covering 11 CWF referenda conducted in 3 US cities from 1956 through 2013. The authors used cluster analysis to identify each article's core rhetoric and classified it according to sentiment and tone. The authors used multilevel count regression models to measure the use of positive and negative words regarding CWF.

RESULTS

Media coverage more closely resembled core rhetoric used by fluoridation opponents than the rhetoric used by fluoridation proponents. Despite the scientific evidence, the media reports were balanced in tone and sentiment for and against CWF. However, in articles emphasizing children, greater negative sentiment was associated with CWF rejection.

CONCLUSIONS

Media coverage depicted an artificial balance of evidence and tone in favor of and against CWF. The focus on children was associated with more negative tone in cities where voters rejected CWF.

PRACTICAL IMPLICATIONS

When speaking to the media, advocates for CWF should emphasize benefits for children and use positive terms about dental health rather than negative terms about dental disease.

Blood Lead Levels and Dental Caries in U.S. Children Who Do Not Drink Tap Water

INTRODUCTION

This study's purpose is to determine whether nonconsumption of tap water is associated with lower prevalence of elevated blood lead levels and higher prevalence of dental caries in children and adolescents.

METHODS

Cross-sectional data from the National Health and Nutrition Examination Survey 2005-2014 recorded drinking water source (n=15,604) and blood lead levels (n=12,373) for participants aged 2-19 years, and dental caries experience for the 2011-2014 subset (n=5,677). The threshold for elevated blood lead level was ≥3 μg/dL. A binary outcome indicated presence or absence of dental caries experience. Multivariable generalized linear models estimated adjusted prevalence ratios with 95% confidence limits.

RESULTS

In analysis conducted in 2017, 15% of children and adolescents did not drink tap water, 3% had elevated blood lead levels ≥3 μg/dL, and 50% had dental caries experience. Children and adolescents who did not drink water were less likely than tap water drinkers to have an elevated blood lead level (adjusted prevalence ratios=0.62, 95% confidence limits=0.42, 0.90). Nonconsumers of tap water were more likely to have dental caries (adjusted prevalence ratios=1.13, 95% confidence limits=1.03, 1.23). Results persisted after adjustment for other covariates and using a higher threshold for elevated blood lead level.

CONCLUSIONS

In this nationally representative U.S. survey, children and adolescents who did not drink tap water had lower prevalence of elevated blood lead levels and higher prevalence of dental caries than those who drank tap water.

Periodontitis and Non-alcoholic Fatty Liver Disease, a population-based cohort investigation in the Study of Health in Pomerania

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) affects 20%-30% of adults with risk factors like obesity and insulin resistance putatively acting through chronic low-grade inflammation. Because periodontitis elicits low-grade inflammation, we hypothesized that it could contribute to NAFLD occurrence.

OBJECTIVE

To investigate epidemiologic associations between periodontitis and the incidence of NAFLD among 2,623 participants of the Study of Health in Pomerania.

METHODS

Periodontitis at baseline was defined as the percentage of sites (0%, <30%, ≥30%) with (i) clinical attachment level (CAL) ≥3 mm; (ii) probing pocket depth (PD) ≥4 mm. Incident NAFLD was defined as a significant increase in liver echogenicity on ultrasound relative to the kidneys, with the diaphragm indistinct or the echogenic walls of the portal veins invisible.

RESULTS

After a median 7.7 years of follow-up, 605 incident NAFLD cases occurred at a rate of 32.5 cases per 1,000 person-years. Relative to participants without CAL ≥3 mm, NAFLD incidence was elevated slightly in participants with <30% of sites affected and moderately in participants with ≥30% of sites affected (multivariable-adjusted incidence rate ratio = 1.28, 95% CI, 0.84, 1.95 and 1.60, 95% CI, 1.05-2.43), respectively. A similar dose-response relationship was not observed for PD.

CONCLUSION

History of periodontitis may be a risk factor for NAFLD.