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OBJECTIVES: To predict the dental caries outcomes in young adults from a set of longitudinally-obtained predictor variables and identify the most important predictors using machine learning techniques. METHODS: This study was conducted using the Iowa Fluoride Study dataset. The predictor variables - sex, mother's education, family income, composite socio-economic status (SES), caries experience at ages 9, 13, and 17, and the cumulative estimates of risk and protective factors, including fluoride, dietary, and behavioral variables from ages 5-9, 9-13, 13-17, and 17-23 were used to predict the age 23 D2+MFS count. The following machine learning models (LASSO regression, generalized boosting machines (GBM), negative binomial (NegGLM), and extreme gradient boosting models (XGBOOST)) were compared under 5-fold cross validation with nested resampling techniques. RESULTS: The prevalence of cavitated level caries experience at age 23 (mean D2+MFS count) was 4.75. The predictive analysis found LASSO to be the best performing model (compared to GBM, NegGLM, and XGBOOST), with a root mean square error (RMSE) of 0.70, and coefficient of determination (R2) of 0.44. After dichotomization of the predicted and observed values of the LASSO regression, the classification results showed accuracy, precision, recall, and ROC AUC of 83.7%, 85.9%, 93.1%, 68.2%, respectively. Previous caries experience at age 13 and age 17 and sugar-sweetened beverages intakes at age 13 and age 17 were found to be the four most important predictors of cavitated caries count at age 23. CONCLUSION: Our machine learning model showed high accuracy and precision in the prediction of caries in young adults from a longitudinally-obtained predictor variables. Our model could, in the future, after further development and validation with other diverse population data, be used by public health specialists and policy-makers as a screening tool to identify the risk of caries in young adults and apply more targeted interventions. However, data from a more diverse population are needed to improve the quality and generalizability of caries prediction.
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Caries Dental , Aprendizaje Automático , Humanos , Caries Dental/epidemiología , Caries Dental/diagnóstico , Masculino , Adulto Joven , Femenino , Adolescente , Niño , Iowa/epidemiología , Estudios Longitudinales , Factores de RiesgoRESUMEN
BACKGROUND: Associations among body composition measures have been limited to cross-sectional analyses of different subjects. We identified cross-sectional relationships between body mass index (BMI) and other body composition measures and predicted body composition measures from BMI throughout childhood and adolescence. METHODS: BMI was calculated and % body fat (%BF), fat mass index (FMI), and fat-free mass index (FFMI) were measured using dual-energy x-ray absorptiometry at ages 5, 9, 11, 13, 15, and 17 years in a birth cohort (n = 629). Sex-specific body composition measures were calculated for BMI-for-age percentiles; associations between BMI and body composition measures were characterized; and body composition measures were predicted from BMI. RESULTS: %BF, FMI, and FFMI generally increased with BMI-for-age percentiles at each age. Correlations between BMI and %BF or FMI were generally higher at BMI-for-age percentiles ≥95% than for lower BMI-for-age percentiles. Correlations between BMI and FFMI were generally higher for participants at very low and very high BMI-for-age percentiles than at moderate BMI-for-age percentiles. Age- and sex-specific predictions from BMI are provided for %BF, FM, and FFMI. CONCLUSIONS: Sex-specific body composition measures throughout childhood and adolescence are presented. BMI is a better indicator of adiposity at higher than at lower BMI values. IMPACT: Sex-specific body composition measures throughout childhood and adolescence are described. % BF, FMI, and FFMI generally increased with BMI-for-age percentiles for both sexes throughout childhood and adolescence. BMI is a better indicator of adiposity at higher BMI levels than at lower BMI values throughout childhood and adolescence.
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Cohorte de Nacimiento , Composición Corporal , Adiposidad , Adolescente , Índice de Masa Corporal , Niño , Femenino , Humanos , Masculino , ObesidadRESUMEN
We propose a Bayesian hurdle mixed-effects model to analyze longitudinal ordinal data under a complex multilevel structure. This research was motivated by the dataset gathered from the Iowa Fluoride Study (IFS) in order to establish the relationships between fluorosis status and potential risk/protective factors. Dental fluorosis is characterized by spots on tooth enamel and is due to ingestion of excessive fluoride intake during enamel formation. Observations are collected from multiple surface zones on each tooth and on all available teeth of children from the studied cohort, which are longitudinally observed at ages 9, 13, and 17. The data not only exhibit a complex hierarchical structure, but also have a large proportion of zero values that are likely to follow different statistical patterns from non-zero categories. Therefore, we develop a hurdle model to consider the zero category separately, while a proportional odds model is used for the positive categories. The estimated parameters are obtained from a Gibbs sampler implemented by the OpenBUGS software. Our model is compared with two popular methods for ordinal data: the proportional odds model and the partial proportional odds model. We perform a comprehensive analysis of the IFS data and evaluate the accuracy and effectiveness of our methodology through simulation studies. Our discoveries provide novel insights to statisticians and dental practitioners about the associations between patient and clinical characteristics and dental fluorosis.
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Dental caries (i.e., cavities) is one of the most common chronic childhood diseases and may continue to progress throughout a person's lifetime. The Iowa Fluoride Study (IFS) was designed to investigate the effects of various fluoride, dietary and nondietary factors on the progression of dental caries among a cohort of Iowa school children. We develop a mixed effects model to perform a comprehensive analysis of the longitudinal clustered data of IFS at ages 5, 9, 13, and 17. We combine a Bayesian hurdle framework with the Conway-Maxwell-Poisson regression model, which can account for both excessive zeros and various levels of dispersion. A hierarchical shrinkage prior distribution is used to share the temporal information for predictors in the fixed-effects model. The dependence among teeth of each individual child is modeled through a sparse covariance structure of the random effects across time. Moreover, we obtain the parameter estimates and credible intervals from a Gibbs sampler. Simulation studies are conducted to assess the accuracy and effectiveness of our statistical methodology. The results of this article provide novel tools to statistical practitioners and offer fresh insights to dental researchers on effects of various risk and protective factors on caries progression.
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Caries Dental , Adolescente , Teorema de Bayes , Niño , Preescolar , Simulación por Computador , Caries Dental/epidemiología , Humanos , Iowa/epidemiología , Distribución de PoissonRESUMEN
The foundation for osteoporosis risk is, in part, established during childhood, adolescence, and young adulthood, all periods of development when bone mass is acquired rapidly. The relative quantity of bone mass accrued is influenced by both lifestyle and genetic factors, although the genetic component is not yet well understood. The purpose of this study was to use a genome-wide association (GWA) analysis to discover single nucleotide polymorphisms (SNPs) associated with: (1) the sex-specific hip bone mineral content at approximately the age of 19 when the amount of bone accrued is near its peak; and (2) the sex-specific rate of hip bone mineral content accrual during the adolescent growth spurt. The Iowa Bone Development Study, a longitudinal cohort study exploring bone health in children, adolescents, and young adults was the source of data. From this cohort, nâ¯=â¯364 (190 females, 174 males) participants were included in GWA analyses to address (1) and nâ¯=â¯258 participants (125 females and 133 males) were included in GWA analyses to address (2). Twenty SNPS were detected having p < 1.0â¯×â¯10-5. Of most biologic relevance were 2 suggestive SNPs (rs2051756 and rs2866908) detected in an intron of the DKK2 gene through the GWA analysis that explored peak bone mass in females.
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Densidad Ósea , Estudio de Asociación del Genoma Completo , Adolescente , Adulto , Densidad Ósea/genética , Desarrollo Óseo/genética , Huesos , Niño , Femenino , Humanos , Estudios Longitudinales , Masculino , Adulto JovenRESUMEN
This study examined the associations of moderate-to-vigorous intensity physical activity (MVPA) trajectories in adolescence through young adulthood with adiposity in young adults. Participants from The Iowa Bone Development Study cohort were longitudinally assessed (N = 297; 57% female). Accelerometry-measured MVPA (min/day) at ages 15 through 23 years, and fat mass and visceral adipose tissue mass indices (kg/m2, g/m2) derived from dual-energy X-ray absorptiometry scans at age 23 years were analyzed. Latent trajectory analyses classified MVPA into two patterns. Multivariable linear regression analyses showed that being in the high MVPA trajectory group was associated with lower fat mass index z-scores. Individuals who were consistently active with high MVPA (vs. moderately active with decreasing MVPA) during adolescence up until early young adulthood had less accumulation of total body adiposity in young adulthood. This study suggests that adopting a consistently active lifestyle throughout adolescence can result in healthier body composition in young adulthood.
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Adiposidad , Ejercicio Físico , Acelerometría , Adolescente , Adulto , Índice de Masa Corporal , Desarrollo Óseo , Femenino , Humanos , Masculino , Obesidad , Adulto JovenRESUMEN
Biological and medical researchers often collect count data in clusters at multiple time points. The data can exhibit excessive zeros and a wide range of dispersion levels. In particular, our research was motivated by a dental dataset with such complex data features: the Iowa Fluoride Study (IFS). The study was designed to investigate the effects of various dietary and nondietary factors on the caries development of a cohort of Iowa school children at the ages of 5, 9, and 13. To analyze the multiyear IFS data, we propose a novel longitudinal method of a generalized estimating equations based marginal regression model. We use a zero-inflated model with a Conway-Maxwell-Poisson (CMP) distribution, which has the flexibility to account for all levels of dispersion. The parameters of interest are estimated through a modified expectation-solution algorithm to account for the clustered and temporal correlation structure. We fit the proposed zero-inflated CMP model and perform a comprehensive secondary analysis of the IFS dataset. It resulted in a number of notable conclusions that also make clinical sense. Additionally, we demonstrated the superiority of this modeling approach over two other popular competing models: the zero-inflated Poisson and negative binomial models. In the simulation studies, we further evaluate the performance of our point estimators, the variance estimators, and that of the large sample confidence intervals for the parameters of interest. It is also demonstrated that our longitudinal CMP model can correctly identify the time-varying dispersion patterns.
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Fluoruros , Modelos Estadísticos , Niño , Simulación por Computador , Humanos , Iowa , Distribución de PoissonRESUMEN
Prior studies suggest dental caries traits in children and adolescents are partially heritable, but there has been no large-scale consortium genome-wide association study (GWAS) to date. We therefore performed GWAS for caries in participants aged 2.5-18.0 years from nine contributing centres. Phenotype definitions were created for the presence or absence of treated or untreated caries, stratified by primary and permanent dentition. All studies tested for association between caries and genotype dosage and the results were combined using fixed-effects meta-analysis. Analysis included up to 19 003 individuals (7530 affected) for primary teeth and 13 353 individuals (5875 affected) for permanent teeth. Evidence for association with caries status was observed at rs1594318-C for primary teeth [intronic within ALLC, odds ratio (OR) 0.85, effect allele frequency (EAF) 0.60, P 4.13e-8] and rs7738851-A (intronic within NEDD9, OR 1.28, EAF 0.85, P 1.63e-8) for permanent teeth. Consortium-wide estimated heritability of caries was low [h2 of 1% (95% CI: 0%: 7%) and 6% (95% CI 0%: 13%) for primary and permanent dentitions, respectively] compared with corresponding within-study estimates [h2 of 28% (95% CI: 9%: 48%) and 17% (95% CI: 2%: 31%)] or previously published estimates. This study was designed to identify common genetic variants with modest effects which are consistent across different populations. We found few single variants associated with caries status under these assumptions. Phenotypic heterogeneity between cohorts and limited statistical power will have contributed; these findings could also reflect complexity not captured by our study design, such as genetic effects which are conditional on environmental exposure.
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Proteínas Adaptadoras Transductoras de Señales/genética , Biomarcadores/análisis , Caries Dental/genética , Dentición Permanente , Estudio de Asociación del Genoma Completo/métodos , Fosfoproteínas/genética , Polimorfismo de Nucleótido Simple , Sitios de Carácter Cuantitativo , Adolescente , Estudios de Casos y Controles , Niño , Preescolar , Femenino , Humanos , Masculino , FenotipoRESUMEN
PURPOSE: Most pediatric physical activity and bone health research has focused on the period immediately around puberty; few have addressed bone structural strength outcomes. This study assessed the magnitude and consistency of the longitudinal relationships between device-measured vigorous-intensity physical activity (VPA) and structural bone strength outcomes across adolescence to emerging adulthood. METHODS: Participants with 3 to 5 bone scans between the age of 11 and 19 years were studied (N = 439, 220 females, 1838 records). Dual-energy X-ray absorptiometry scans of the hip (hip structural analysis) and peripheral quantitative computed tomography scans of the tibia were obtained. Outcomes included femoral neck section modulus, femoral neck cross-sectional area, tibial Bone Strength Index, and tibial torsion strength (polar Strength Strain Index). Sex-specific bone mixed growth models were developed using biological age (chronological age - age at peak height velocity) as the time variable, and height, weight, and device-measured VPA as time-varying covariates. Models also included the VPA-biological age interaction. RESULTS: Individual-centered VPA and the VPA-biological age interaction were significantly, positively associated (P < .05) with Bone Strength Index, polar Strength Strain Index, section modulus, and cross-sectional area in males and females, indicating accumulative effects of VPA throughout maturation and beyond. CONCLUSION: Bone remains responsive to the mechanical loading of physical activity throughout adolescence and into emerging adulthood. Attention should be placed on promoting bone-strengthening physical activity after the prepubertal years when adult exercise patterns are likely formed.
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Densidad Ósea , Desarrollo Óseo , Ejercicio Físico , Absorciometría de Fotón , Adolescente , Niño , Femenino , Cuello Femoral/diagnóstico por imagen , Humanos , Iowa , Estudios Longitudinales , Masculino , Valores de Referencia , Adulto JovenRESUMEN
Background: Height is an indicator of nutritional status; linear growth faltering has recognized consequences for cognitive, emotional, and chronic disease risk. Although height is routinely studied in developing countries, less attention is given to height in the United States. Objective: The objective of this study was to identify longitudinal associations between childhood and adolescent beverage intakes, nutrient adequacy, or energy intake and height in a birth cohort. Methods: Data for participants through ages 2-17 y (n = 717; 353 males, 364 females) recruited at birth for the longitudinal Iowa Fluoride Study (IFS) were used in the current cohort analyses. Beverage intakes (n = 708) were collected by beverage-frequency questionnaires at 3- to 6-mo intervals, whereas nutrient data (n = 652) were obtained from 3-d food diaries completed at 3- to 6-mo intervals through age 8.5 y and from Block Kids' food-frequency questionnaires at 2-y intervals after age 8.5 y. Nutrient adequacy ratios were calculated with the use of age- and sex-specific Estimated Average Requirements. Height was measured at clinic visits when the participants were approximately ages 5, 9, 11, 13, 15, and 17 y. Linear mixed models were used to identify longitudinal associations between dietary variables and height. A baseline model that adjusted for changing growth patterns during adolescence was established. Dietary and potential confounding variables were added to this baseline model. Results: Milk intake adjusted for mean adequacy ratio, energy intake, and baseline socioeconomic status was associated with height; for each additional 8 ounces (236 mL) of milk consumed per day throughout childhood and adolescence, height increased, on average, by 0.39 cm (95% CI: 0.18, 0.60 cm; P < 0.001). Conclusions: IFS participants' height increased by 0.39 cm for each additional 8 ounces (236 mL) of milk consumed throughout childhood and adolescence. The clinical implications of the mild linear growth faltering observed in healthy youth are unknown. This trial was registered at www.clinicaltrials.gov as 199112665.
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Estatura , Fenómenos Fisiológicos Nutricionales Infantiles , Encuestas sobre Dietas , Leche , Adolescente , Animales , Niño , Preescolar , Estudios de Cohortes , Dieta , Registros de Dieta , Ingestión de Energía , Femenino , Humanos , MasculinoRESUMEN
In practice, count data may exhibit varying dispersion patterns and excessive zero values; additionally, they may appear in groups or clusters sharing a common source of variation. We present a novel Bayesian approach for analyzing such data. To model these features, we combine the Conway-Maxwell-Poisson distribution, which allows both overdispersion and underdispersion, with a hurdle component for the zeros and random effects for clustering. We propose an efficient Markov chain Monte Carlo sampling scheme to obtain posterior inference from our model. Through simulation studies, we compare our hurdle Conway-Maxwell-Poisson model with a hurdle Poisson model to demonstrate the effectiveness of our Conway-Maxwell-Poisson approach. Furthermore, we apply our model to analyze an illustrative dataset containing information on the number and types of carious lesions on each tooth in a population of 9-year-olds from the Iowa Fluoride Study, which is an ongoing longitudinal study on a cohort of Iowa children that began in 1991.
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Teorema de Bayes , Análisis por Conglomerados , Distribución de Poisson , Niño , Simulación por Computador , Interpretación Estadística de Datos , Caries Dental/prevención & control , Fluoruros/uso terapéutico , Humanos , Iowa , Estudios Longitudinales , Cadenas de Markov , Método de MontecarloRESUMEN
Survival analyses have been used to overcome some of the limitations encountered with other statistical analyses. Although extended Cox hazard modeling with time-dependent variables has been utilized in several medical studies, it has never been utilized in assessing the complex relationship between mutans streptococci (MS) acquisition (time-dependent covariate) and time to having dental caries (outcome). This study involved secondary analyses of data from a prospective study conducted at the University of Alabama at Birmingham. Low socioeconomic status, African-American preschool children from Perry County, AL, USA (n = 95) had dental examinations at age 1 year and annually thereafter until age 6 years by three calibrated dentists. Salivary MS tests were done at ages 1, 1.5, 2, 2.5, 3, and 4 years. The patterns of and relationship between initial MS detection (time-dependent covariate) and dental caries experience occurrence were assessed, using extended Cox hazard modeling. The median time without MS acquisition (50% of the children not having positive MS test) was 2 years. Approximately 79% of the children had positive salivary MS tests by the age of 4 years. The median caries experience survival (50% of the children not having dental caries) was 4 years. During the follow-up period, 65 of the children (68.4%) had their initial primary caries experience. Results of the extended Cox hazard modeling showed a significant overall/global relationship between initial caries experience event at any given time during the follow-up period and having a positive salivary MS test at any time during the follow-up period (hazard ratio = 2.25, 95% CI 1.06-4.75). In conclusion, the extended Cox modeling was used for the first time and its results showed a significant global/overall relationship between MS acquisition and dental caries. Further research using causal mediation analysis with survival data is necessary, where the mediator "presence of MS" is treated as a time-dependent variable.
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Caries Dental/microbiología , Modelos Estadísticos , Streptococcus mutans , Factores de Edad , Niño , Preescolar , Caries Dental/etiología , Humanos , Lactante , Estimación de Kaplan-Meier , Estudios Longitudinales , Modelos de Riesgos Proporcionales , Saliva/microbiologíaRESUMEN
OBJECTIVE: A genetic component in early childhood caries (ECC) is theorized, but no genome-wide investigations of ECC have been conducted. This pilot study is part of a long-term research program aimed to: (1) determine the proportion of ECC variance attributable to the human genome and (2) identify ECC-associated genetic loci. METHODS: The study's community-based sample comprised 212 children (mean age=39 months; range = 30-52 months; males = 55%; Hispanic/Latino = 35%, African-American = 32%; American Academy of Pediatric Dentistry definition of ECC prevalence = 38%). Approximately 2.4 million single nucleotide polymorphisms (SNPs) were genotyped using DNA purified from saliva. A P < 5 × 10-8 criterion was used for genome-wide significance. SNPs with P < 5 × 10-5 were followed-up in three independent cohorts of 921 preschool-age children with similar ECC prevalence. RESULTS: SNPs with minor allele frequency ≥5% explained 52% (standard error = 54%) of ECC variance (one-sided P = 0.03). Unsurprisingly, given the pilot's small sample size, no genome-wide significant associations were found. An intergenic locus on 4q32 (rs4690994) displayed the strongest association with ECC [P = 2.3 × 10-6 ; odds ratio (OR) = 3.5; 95% confidence interval (CI) = 2.1-5.9]. Thirteen loci with suggestive associations were followed-up - none showed evidence of association in the replication samples. CONCLUSION: This study's findings support a heritable component of ECC and demonstrate the feasibility of conducting genomics studies among preschool-age children.
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Caries Dental/genética , Preescolar , Caries Dental/epidemiología , Femenino , Frecuencia de los Genes/genética , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad/genética , Humanos , Masculino , North Carolina/epidemiología , Proyectos Piloto , Polimorfismo de Nucleótido Simple/genética , PrevalenciaRESUMEN
BACKGROUND: Dental caries is a common chronic disease among children and adults alike, posing a substantial health burden. Caries is affected by multiple genetic and environmental factors, and prior studies have found that a substantial proportion of caries susceptibility is genetically inherited. METHODS: To identify such genetic factors, we conducted a genome-wide linkage scan in 464 extended families with 2616 individuals from Iowa, Pennsylvania and West Virginia for three dental caries phenotypes: (1) PRIM: dichotomized as zero versus one or more affected primary teeth, (2) QTOT1: age-adjusted quantitative caries measure for both primary and permanent dentitions including pre-cavitated lesions, and (3) QTOT2: age-adjusted quantitative caries excluding pre-cavitated lesions. Genotyping was conducted for approximately 600,000 SNPs on an Illumina platform, pruned to 127,511 uncorrelated SNPs for the analyses reported here. RESULTS: Multipoint non-parametric linkage analyses generated peak LOD scores exceeding 2.0 for eight genomic regions, but no LOD scores above 3.0 were observed. The maximum LOD score for each of the three traits was 2.90 at 1q25.3 for PRIM, 2.38 at 6q25.3 for QTOT1, and 2.76 at 5q23.3 for QTOT2. Some overlap in linkage regions was observed among the phenotypes. Genes with a potential role in dental caries in the eight chromosomal regions include CACNA1E, LAMC2, ALMS1, STAMBP, GXYLT2, SLC12A2, MEGF10, TMEM181, ARID1B, and, as well as genes in several immune gene families. Our results are also concordant with previous findings from association analyses on chromosomes 11 and 19. CONCLUSIONS: These multipoint linkage results provide evidence in favor of novel chromosomal regions, while also supporting earlier association findings for these data. Understanding the genetic etiology of dental caries will allow designing personalized treatment plans based on an individual's genetic risk of disease.
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Susceptibilidad a Caries Dentarias/genética , Caries Dental/genética , Adolescente , Adulto , Niño , Preescolar , Cromosomas Humanos/genética , Estudio de Asociación del Genoma Completo , Humanos , Iowa , Escala de Lod , Persona de Mediana Edad , Pennsylvania , Fenotipo , Polimorfismo de Nucleótido Simple , West Virginia , Adulto JovenRESUMEN
A recent genome-wide association study (GWAS) for dental caries nominated the chromosomal region 4q21 near ABCG2, PKD2 and the SIBLING (small integrin-binding ligand N-linked glycoprotein) gene family. In this investigation, we followed up and fine-mapped this region using a tag-SNP (single-nucleotide polymorphism) approach in 13 age- and race-stratified samples from 6 independent studies (N=4089). Participants were assessed for dental caries via intraoral examination and 49 tag-SNPs were genotyped capturing much of the variation in the 4q21 locus. Linear models were used to test for genetic association, while adjusting for sex, age and components of ancestry. SNPs in and near PKD2 showed significant evidence of association in individual samples of black adults (rs17013735, P-value=0.0009) and white adults (rs11938025; P-value=0.0005; rs2725270, P-value=0.003). Meta-analyses across black adult samples recapitulated the association with rs17013735 (P-value=0.003), which occurs at low frequency in non-African populations, possibly explaining the race specificity of the effect. In addition to race-specific associations, we also observed evidence of gene-by-fluoride exposure interaction effects in white adults for SNP rs2725233 upstream of PKD2 (P=0.002). Our results show evidence of regional replication, though no single variant clearly accounted for the original GWAS signal. Therefore, while we interpret our results as strengthening the hypothesis that chromosome 4q21 may impact dental caries, additional work is needed.
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Caries Dental/genética , Estudios de Asociación Genética , Proteínas Quinasas/genética , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/genética , Adulto , Negro o Afroamericano/genética , Mapeo Cromosómico , Cromosomas Humanos Par 4/genética , Caries Dental/patología , Femenino , Predisposición Genética a la Enfermedad , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Proteínas de Neoplasias/genética , Polimorfismo de Nucleótido Simple , Proteína Quinasa D2 , Población Blanca/genéticaRESUMEN
Community water fluoridation is an important public health measure to prevent dental caries, but it continues to be somewhat controversial. The Iowa Fluoride Study (IFS) is a longitudinal study on a cohort of Iowa children that began in 1991. The main purposes of this study (http://www.dentistry.uiowa.edu/preventive-fluoride-study) were to quantify fluoride exposures from both dietary and nondietary sources and to associate longitudinal fluoride exposures with dental fluorosis (spots on teeth) and dental caries (cavities). We analyze a subset of the IFS data by a marginal regression model with a zero-inflated version of the Conway-Maxwell-Poisson distribution for count data exhibiting excessive zeros and a wide range of dispersion patterns. In general, we introduce two estimation methods for fitting a ZICMP marginal regression model. Finite sample behaviors of the estimators and the resulting confidence intervals are studied using extensive simulation studies. We apply our methodologies to the dental caries data. Our novel modeling incorporating zero inflation, clustering, and overdispersion sheds some new light on the effect of community water fluoridation and other factors. We also include a second application of our methodology to a genomic (next-generation sequencing) dataset that exhibits underdispersion.
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Interpretación Estadística de Datos , Modelos Estadísticos , Análisis de Regresión , Biometría/métodos , Análisis por Conglomerados , Simulación por Computador , Intervalos de Confianza , Agua Potable , Fluoruración , Genómica , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Distribución de PoissonRESUMEN
BACKGROUND: Parental characteristics that influence child physical activity (PA) behavior often co-occur. An analytic approach that considers these co-occurring patterns can help researchers better understand the overall context of parental influence. The study aims were to: (1) identify diverse patterns of the relationships among parental characteristics, (2) examine the influence of these parental patterns on child sport participation and moderate-to vigorous-intensity PA (MVPA) trajectories during childhood and adolescence, and (3) examine whether family support mediates the influence of the parental patterns on child sport participation and MVPA trajectories. METHODS: We used data from 408 Iowa Bone Development Study cohort families (97% Caucasians; 65 % mothers with a 4-year college degree). From ages 5 to 19 years, the cohort participated in seven accelerometry assessments, reported sports participation every 6 months, and reported perceived family support for PA at age 15. Parents reported family income, education level, and regular PA participation in high school and adulthood. Structural equation modeling was conducted to identify the latent classes represented among these parental characteristics. Sex-adjusted multivariable logistic regression analyses were conducted to predict sports participation trajectories and MVPA trajectories by latent class and family support. RESULTS: Three parent latent classes were identified: higher family socioeconomic status (SES) and regular PA in both high school and adulthood by both the father and mother (Group 1); lower family SES and regular PA in high school by the father (Group 2); and lower family SES and no regular PA in high school by the father (Group 3). Sex-adjusted ORs of the "drop-out from sports participation" pattern for the children in Groups 1 and 2, compared to Group 3, were 0.38 (95% CI = 0.20, 0.72) and 0.51 (95% CI = 0.26, 1.00), respectively. Sex-adjusted ORs of the "decreasing from moderate MVPA" pattern for the children in Groups 1 and 2, compared to Group 3, were 0.29 (95% CI = 0.11, 0.75) and 1.16 (95% CI = 0.40, 3.37), respectively. Adding family support to the logistic regression model only slightly changed the ORs. CONCLUSIONS: The findings from this study suggest that among lower SES families, the father's role may be important to promote youth to sustain sports participation.
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Conducta del Adolescente , Conducta Infantil , Ejercicio Físico , Padre , Relaciones Padres-Hijo , Clase Social , Deportes , Acelerometría , Adolescente , Niño , Preescolar , Estudios de Cohortes , Relaciones Familiares , Femenino , Conductas Relacionadas con la Salud , Humanos , Iowa , Modelos Logísticos , Masculino , Madres , Oportunidad Relativa , Padres , Apoyo SocialRESUMEN
BACKGROUND/AIMS: Recruitment of parent/infant pairs can be more difficult and challenging than recruitment of adult subjects alone as the parent has to consider themselves along with the infant to be study participants. In order to determine which recruitment methods most effectively resulted in accrual of subjects, recruitment efforts at the University of Iowa were evaluated, one of three clinical sites involved in a longitudinal prospective study of dental caries. METHODS: Enrollment goals were 300 parent/infant pairs within a year. Recruitment strategies included (1) a direct mailing to potential subjects who were University of Iowa Hospitals and Clinics patients and potentially met inclusion criteria; (2) face-to-face recruitment visits at medical offices; (3) provision of recruitment materials to staff at off-campus agencies and medical offices serving low-income individuals; (4) a campus-wide mass e-mail; (5) recruitment materials to daycare centers and neighborhood centers; and (6) recruitment at a children's museum. RESULTS: From these recruitment efforts, 515 potential participants expressed interest and were screened for this study and 348 (68%) were enrolled during an 11-month time period. The face-to-face strategy had the highest recruitment rate of 25%, followed by direct individual mailings at 9% and follow-up telephone calls at 7%. For the face-to-face strategy, the contact at the children's museum was most successful compared to the other office settings. The lowest rate of recruitment of 0.09% was attained with the mass e-mail. However, in terms of actual numbers recruited, the mass e-mail remained an important modality since it yielded 21 recruits and was much less time-intensive. CONCLUSION: An intensive, multi-pronged recruitment strategy proved successful in meeting enrollment goals and resulted in finishing the enrollment prior to the projected study deadline. Effective recruitment approaches are imperative for a study's success and each recruitment strategy needs to be budgeted and planned for in a study. Investigators may need to adapt their approach to attain the needed number of subjects. Planning needs to include the numbers needed to be approached to attain your recruitment goal, how you will recruit, who will be responsible, and the costs and time commitment for various strategies.
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Caries Dental , Padres , Selección de Paciente , Humanos , Lactante , Iowa , Estudios Longitudinales , Estudios ProspectivosRESUMEN
OBJECTIVES: In humans, there is a large range of variation in the form of the maxillary and mandibular dental arches. This variation can manifest as either prognathism or retrognathism in either or both arches, which can cause malocclusion and lead to abnormal masticatory function. This study aims to identify aspects of variation and morphological integration existing in the dental arches of individuals with different types of malocclusion. METHODS: Coordinate landmark data were collected along the gingival margins of 397 scanned dental casts and then analyzed using geometric morphometric techniques to explore arch form variation and patterns of morphological integration within each malocclusion type. RESULTS: Significant differences were identified between Class II forms (increased projection of upper arch relative to the lower arch) and Class III forms (lower arch projection beyond the upper arch) in symmetrical shape variation, including anteroposterior arch discrepancies and abnormal anterior arch divergence or convergence. Partial least squares analysis demonstrated that Class III dental arches have higher levels of covariance between upper and lower arches (RV = 0.91) compared to the dental arches of Class II (RV = 0.78) and Class I (RV = 0.73). These high levels of covariance, however, are on the lower end of the overall range of possible masticatory blocks, indicating weaker than expected levels of integration. CONCLUSIONS: This study provides evidence for patterns of variation in dental arch shape found in individuals with Class II and Class III malocclusions. Moreover, differences in integration found between malocclusion types have ramifications for how such conditions should be studied and treated. Am. J. Hum. Biol. 28:879-889, 2016. © 2016Wiley Periodicals, Inc.
Asunto(s)
Arco Dental/anatomía & histología , Maloclusión/patología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Arco Dental/patología , Femenino , Humanos , Iowa , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Adulto JovenRESUMEN
PURPOSE: Little is known about use or acceptance of minimally invasive dentistry (MID) in the USA, particularly in public health settings. The purpose of this study was to assess opinions concerning MID among dentists in public-health practices. MATERIALS AND METHODS: A cross-sectional study was conducted to assess the views of dentists in public-health practices concerning MID using an online survey instrument among National Network for Oral Health Access (NNOHA) and American Association of Community Dental Programs (AACDP) members. Specific questions focused on diagnostic and preventive techniques, and whether MID was considered to meet the standard of care in the US Results: Overall, 86% believed that MID met the standard of care for primary teeth, and 77% did so for permanent teeth. The majority of respondents also agreed that fluoride varnish prevents caries and atraumatic restorative techniques (ART) are an effective caries treatment for children and adults. According to logistic regression results, dentists who had continuing education courses in MID and agreed that ART was an effective treatment for adults were more likely to report that MID met the standard of care for permanent teeth. Subjects who believed that fluoride varnish was effective as caries prevention for children were more likely to view MID as meeting the standard of care for primary teeth. CONCLUSIONS: There appears to be a paradigm shift toward a MID philosophy, and most responding public health dentists believed that MID meets the standard of care for primary and permanent teeth in the US.