Objectives
To assess long‐term attachment and periodontitis‐related tooth loss (PTL) in untreated periodontal disease over 40 years.
Material and Methods
Data originated from the natural history of ...periodontitis study in Sri Lankan tea labourers first examined in 1970. In 2010, 75 subjects (15.6%) of the original cohort were re‐examined.
Results
PTL over 40 years varied between 0 and 28 teeth (mean 13.1). Four subjects presented with no PTL, while 12 were edentulous. Logistic regression revealed attachment loss as a statistically significant covariate for PTL (p < .004). Markov chain analysis showed that smoking and calculus were associated with disease initiation and that calculus, plaque, and gingivitis were associated with loss of attachment and progression to advanced disease. Mean attachment loss <1.81 mm at the age of 30 yielded highest sensitivity and specificity (0.71) to allocate subjects into a cohort with a dentition of at least 20 teeth at 60 years of age.
Conclusions
These results highlight the importance of treating early periodontitis along with smoking cessation, in those under 30 years of age. They further show that calculus removal, plaque control, and the control of gingivitis are essential in preventing disease progression, further loss of attachment and ultimately tooth loss.
Enormous unmet needs for infertility treatment exist because access to assisted reproductive technologies is demographically skewed. Since the first IVF baby in 1978, the number of people conceived ...by reproductive technology has grown much faster than expected, reaching several million today and rapidly approaching 0.1% of the total world population. As more patients build families, and their children in turn become parents, the number owing their existence to assisted reproductive technologies, either directly or indirectly, will expand tremendously in future decades, but no attempts have been made hitherto to project the magnitude. We have projected growth to the year 2100, along with the fractional contribution to world population. The chief variable driving growth is access to fertility services. If it stagnates at current levels of about 400,000 babies per year, an estimated 157 million people alive at the end of the century will owe their lives to assisted reproductive technologies (1.4% of global population), but at an arbitrary upper limit of 30,000 extra births annually there will be 394 million additional people alive (3.5%). As the conquest of infertility continues, individuals who owe their lives to assisted reproductive technologies will quietly make a significant contribution to demographic growth as well as social progress.
Menopause is the consequence of exhaustion of the ovarian follicular pool. AMH, an indirect hormonal marker of ovarian reserve, has been recently proposed as a predictor for age at menopause. Since ...BMI and smoking status are relevant independent factors associated with age at menopause we evaluated whether a model including all three of these variables could improve AMH-based prediction of age at menopause.
In the present cohort study, participants were 375 eumenorrheic women aged 19-44 years and a sample of 2,635 Italian menopausal women. AMH values were obtained from the eumenorrheic women.
Regression analysis of the AMH data showed that a quadratic function of age provided a good description of these data plotted on a logarithmic scale, with a distribution of residual deviates that was not normal but showed significant left-skewness. Under the hypothesis that menopause can be predicted by AMH dropping below a critical threshold, a model predicting menopausal age was constructed from the AMH regression model and applied to the data on menopause. With the AMH threshold dependent on the covariates BMI and smoking status, the effects of these covariates were shown to be highly significant.
In the present study we confirmed the good level of conformity between the distributions of observed and AMH-predicted ages at menopause, and showed that using BMI and smoking status as additional variables improves AMH-based prediction of age at menopause.
This article describes the R package BinaryEPPM and its use in determining maximum likelihood estimates of the parameters of extended Poisson process models for grouped binary data. These provide a ...Poisson process family of flexible models that can handle unlimited under-dispersion but limited over-dispersion in such data, with the binomial distribution being a special case. Within BinaryEPPM, models with the mean and variance related to covariates are constructed to match a generalized linear model formulation. Combining such under-dispersed models with standard over-dispersed models such as the beta binomial distribution provides a very general form of residual distribution for modeling grouped binary data. Use of the package is illustrated by application to several data-sets.
This article describes the R package CountsEPPM and its use in determining maximum likelihood estimates of the parameters of extended Poisson process models. These provide a Poisson process based ...family of flexible models that can handle both underdispersion and overdispersion in observed count data, with the negative binomial and Poisson distributions being special cases. Within CountsEPPM models with mean and variance related to covariates are constructed to match a generalized linear model formulation. Use of the package is illustrated by application to several published datasets.
Background: Triclosan toothpaste is effective in controlling plaque and gingivitis and slowing progression of periodontitis; however, its influence on inflammatory biomarkers of cardiovascular ...disease (CVD), as well as on kidney and liver function, is unknown.
Methods: Patients recruited from the Cardiovascular Unit at Prince Charles Hospital, Brisbane, Australia, were randomized to triclosan (n = 193) or placebo (n = 190) groups and assessed for total cholesterol (TC), high density lipoprotein (HDL) and low density lipoprotein (LDL) cholesterol, triglycerides, C‐reactive protein, erythrocyte sedimentation rate (ESR), hemoglobin, total white cell count (WCC), estimated glomerular filtration rate (eGFR), and liver function enzymes, annually for 5 years. A standard mixed model for each marker included group, sex, age, hypertension, diabetes, periodontal status, statin and anti‐inflammatory drug use, and smoking as covariates. Changes in eGFR, WCC, and ESR were further analyzed using transition modeling.
Results: Triclosan toothpaste led to a greater decrease in TC (P = 0.03), LDL cholesterol (P = 0.04), and HDL cholesterol (P = 0.05) than placebo toothpaste. ESR increased at a slower rate in the triclosan group (P ≈ 0.06) and was less likely to increase and more likely to improve in males on statins but not anti‐inflammatory drugs in the triclosan group versus the placebo group. Markov modeling of the binary response for eGFR (greater than or less than/equal to the baseline median value) showed that patients with diabetes in the placebo group were significantly (P ≈ 0.05) more likely to deteriorate than either patients with diabetes in the triclosan group or patients without diabetes in each group.
Conclusions: These data suggest that triclosan toothpaste may influence some inflammatory biomarkers of CVD, but not kidney or liver function. However, it is unclear if this influence is clinically significant.
We present a novel approach for developing summary statistics for use in approximate Bayesian computation (ABC) algorithms by using indirect inference. ABC methods are useful for posterior inference ...in the presence of an intractable likelihood function. In the indirect inference approach to ABC the parameters of an auxiliary model fitted to the data become the summary statistics. Although applicable to any ABC technique, we embed this approach within a sequential Monte Carlo algorithm that is completely adaptive and requires very little tuning. This methodological development was motivated by an application involving data on macroparasite population evolution modelled by a trivariate stochastic process for which there is no tractable likelihood function. The auxiliary model here is based on a beta-binomial distribution. The main objective of the analysis is to determine which parameters of the stochastic model are estimable from the observed data on mature parasite worms.
The variability in ultrasound-based antral follicle counts sized 2-10 mm after allowing for age-related decline is considerable. This may represent differences in actual reproductive age among women. ...This hypothesis was tested by cohort comparison for distribution of age at occurrence of reproductive events.
A model with a nonlinear mean decline with age was fitted to antral follicle counts (AFC) obtained in 163 regularly cycling fertile volunteers. Ages at last child birth and menopause were predicted from the individual AFC by using thresholds to represent these events and the model for decline with age. Distributions of the observed ages at last childbirth (proxy variable for loss of natural fertility) and ages at menopause were obtained from the BALSAC demographic database and the Prospect-EPIC study, respectively. The observed distributions were compared with the predicted distributions by using visual comparison and quantile-quantile plots. Predictions of age at last child and age at menopause were done using percentiles of the modeled AFC distribution for given age, and corresponding percentiles of the predicted distributions of age at these reproductive events, with predictions following from the position of a woman's AFC relative to these percentiles.
The predicted distributions of age at last child and age at menopause showed good agreement with the observed distributions in the BALSAC and EPIC cohort. Compared with age alone, antral follicle counts gave some additional information for individual prediction of age at last child and menopause.
The link between declining antral follicle counts and reproductively significant events like loss of natural fertility and menopause is strengthened by the high degree of similarity among the predicted and observed age distributions. Predictive usefulness of this relationship in a clinical setting may be more marginal, except in the case of women who have low AFCs for their age.
Eggs forever? Byskov, Anne Grete; Faddy, Malcolm J.; Lemmen, Josephine G. ...
Differentiation (London),
December 2005, Letnik:
73, Številka:
9
Journal Article
Recenzirano
A group of scientists from Harvard Medical School (Johnson et al., 2004) claims to have “established the existence of proliferative germ cells that sustain oocyte and follicle production in the ...postnatal mammalian ovary,” expressing no doubts about their methods, results and conclusion. Johnson et al. based their conclusions of oocyte and follicular renewal from existing germline stem cells (GSC) in the postnatal mouse ovary on three types of observations: (1) A claimed discordance in follicle loss versus follicle atresia in the neonatal period and in the following pubertal and adult period; (2) immunohistochemical detection of proliferating GSC with meiotic capacity using combined markers for meiosis, germline, and mitosis; and (3) neo-folliculogenesis in ovarian chimeric grafting experiments with adult mice.
Oogenesis is the process that transforms the proliferative oogonium into an oocyte through meiosis, followed by folliculogenesis and follicular and oocyte maturation. The most crucial part in producing a functional oocyte is firstly, initiation and completion of the first meiotic prophase, and secondly, enclosure of the resulting diplotene oocyte in a follicle. Neither of these two events has been shown to take place in Johnson et al.'s study of the postnatal mouse ovary. We hereby address the observations underpinning their hypothesis and conclude that it is premature to replace the paradigm that adult mammalian neo-oogenesis/folliculogenesis does not take place.
Background: The factors associated with initial periodontitis are not well understood and cannot be identified by cross‐sectional studies.
Aim: To identify the factors associated with the initiation ...of chronic periodontitis using ante‐dependence modelling.
Material and Methods: A 26‐year longitudinal study of the natural history of periodontitis served as the basis for the study. In 1969, 565 Norwegian men aged 16–34 years were surveyed. Subsequent surveys were performed in 1971, 1973, 1975, 1981, 1988 and finally in 1995, with 223 remaining subjects. Plaque (PlI), gingival (GI) and calculus indices (CI) and loss of attachment (LoA) were recorded. Ante‐dependence modelling using a Markov chain enabled the results of this sequence of examinations to be analysed longitudinally, taking into account serial dependence, describing temporal changes in patients' levels of disease and allowing for both progression and regression between disease categories.
Results: With age, the rate of disease regression decreased. Increasing calculus accumulation and smoking increased the rate of disease progression, while increasing GI increased the rate of regression.
Conclusions: Increased mean CI and smoking were significant predictive covariates for progression, while increased mean GI and younger age predicted regression of initial periodontitis.
PDF
