Subclinical thyroid dysfunction and cognitive decline in old age

<p>Background: Subclinical thyroid dysfunction has been implicated as a risk factor for cognitive decline in old age, but results are inconsistent. We investigated the association between subclinical thyroid dysfunction and cognitive decline in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER).</p> <p>Methods: Prospective longitudinal study of men and women aged 70–82 years with pre-existing vascular disease or more than one risk factor to develop this condition (N = 5,154). Participants taking antithyroid medications, thyroid hormone supplementation and/or amiodarone were excluded. Thyroid function was measured at baseline: subclinical hyper- and hypothyroidism were defined as thyroid stimulating hormones (TSH) <0.45 mU/L or >4.50 mU/L respectively, with normal levels of free thyroxine (FT4). Cognitive performance was tested at baseline and at four subsequent time points during a mean follow-up of 3 years, using five neuropsychological performance tests.</p> <p>Results: Subclinical hyperthyroidism and hypothyroidism were found in 65 and 161 participants, respectively. We found no consistent association of subclinical hyper- or hypothyroidism with altered cognitive performance compared to euthyroid participants on the individual cognitive tests. Similarly, there was no association with rate of cognitive decline during follow-up.</p> <p>Conclusion: We found no consistent evidence that subclinical hyper- or hypothyroidism contribute to cognitive impairment or decline in old age. Although our data are not in support of treatment of subclinical thyroid dysfunction to prevent cognitive dysfunction in later life, only large randomized controlled trials can provide definitive evidence.</p&gt

Subclinical thyroid dysfunction and cognitive decline in old age

<p>Background: Subclinical thyroid dysfunction has been implicated as a risk factor for cognitive decline in old age, but results are inconsistent. We investigated the association between subclinical thyroid dysfunction and cognitive decline in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER).</p> <p>Methods: Prospective longitudinal study of men and women aged 70–82 years with pre-existing vascular disease or more than one risk factor to develop this condition (N = 5,154). Participants taking antithyroid medications, thyroid hormone supplementation and/or amiodarone were excluded. Thyroid function was measured at baseline: subclinical hyper- and hypothyroidism were defined as thyroid stimulating hormones (TSH) <0.45 mU/L or >4.50 mU/L respectively, with normal levels of free thyroxine (FT4). Cognitive performance was tested at baseline and at four subsequent time points during a mean follow-up of 3 years, using five neuropsychological performance tests.</p> <p>Results: Subclinical hyperthyroidism and hypothyroidism were found in 65 and 161 participants, respectively. We found no consistent association of subclinical hyper- or hypothyroidism with altered cognitive performance compared to euthyroid participants on the individual cognitive tests. Similarly, there was no association with rate of cognitive decline during follow-up.</p> <p>Conclusion: We found no consistent evidence that subclinical hyper- or hypothyroidism contribute to cognitive impairment or decline in old age. Although our data are not in support of treatment of subclinical thyroid dysfunction to prevent cognitive dysfunction in later life, only large randomized controlled trials can provide definitive evidence.</p&gt

Evidence of a high incidence of subclinically affected calves in a herd of cattle with fatal cases of Bovine Neonatal Pancytopenia (BNP).

BACKGROUND: Bovine Neonatal Pancytopenia (BNP) is a disease of calves characterised by bone marrow trilineage hypoplasia, mediated by ingestion of alloantibodies in colostrum. Suspected subclinical forms of BNP have been reported, suggesting that observed clinical cases may not represent the full extent of the disease. However to date there are no objective data available on the incidence of subclinical disease or its temporal distribution. This study aimed to 1) ascertain whether subclinical BNP occurs and, if so, to determine the incidence on an affected farm and 2) determine whether there is evidence of temporal clustering of BNP cases on this farm. To achieve these aims, haematological screening of calves born on the farm during one calving season was carried out, utilising blood samples collected at defined ages. These data were then analysed in comparison to data from both known BNP-free control animals and histopathologically confirmed BNP cases. An ordinal logistic regression model was used to create a composite haematology score to predict the probabilities of calves being normal, based on their haematology measurements at 10–14 days old. RESULTS: This study revealed that 15% (21 of 139) of the clinically normal calves on this farm had profoundly abnormal haematology (<5% chance of being normal) and could be defined as affected by subclinical BNP. Together with clinical BNP cases, this gave the study farm a BNP incidence of 18%. Calves with BNP were found to be distributed throughout the calving period, with no clustering, and no significant differences in the date of birth of cases or subclinical cases were found compared to the rest of the calves. This study did not find any evidence of increased mortality or increased time from birth to sale in subclinical BNP calves but, as the study only involved a single farm and adverse effects may be determined by other inter-current diseases it remains possible that subclinical BNP has a detrimental impact on the health and productivity of calves under certain circumstances. CONCLUSIONS: Subclinical BNP was found to occur at a high incidence in a herd of cattle with fatal cases of BNP

Relationship of herd average somatic cell count and spontaneous recovery from subclinical mastitis

The rate of spontaneous recovery from subclinical mastitis was evaluated in 56 Kansas. DHI herds participating in the Somatic Cell Count (SCC) program. Herds were classified as low (>300,000) or high (>600,000) based on herd sec average. Comparisons between low and high SCC-herds were made for each cow's ability to recover from a subclinical case of mastitis (>600,000 SCC). Low-SCC herds had a rate of spontaneous recovery that was more than three times greater than that of high-SCC herds. Average SCC of cows with subclinical mastitis was similar in low and high herds J as well as the average sec of cows following spontaneous recovery. Results illustrate the importance of monitoring monthly sec reports. Proper attention to good procedures of milking management includes: attention to milking techniques, proper function of milking equipment, and attention to sanitation and housing conditions. As a result, herds with low SCC tests will have higher production and fewer subclinical cases of mastitis

Abnormal Perceptual Sensitivity in Body-Focused Repetitive Behaviors

Objective Several compulsive grooming habits such as hair pulling, skin picking, and nail biting are collectively known as body-focused repetitive behaviors (BFRBs). Although subclinical BFRBs are common and benign, more severe and damaging manifestations exist that are difficult to manage. Researchers have suggested that BFRBs are maintained by various cognitive, affective, and sensory contingencies. Although the involvement of cognitive and affective processes in BFRBs has been studied, there is a paucity of research on sensory processes. Methods The current study tested whether adults with subclinical or clinical BFRBs would report abnormal patterns of sensory processing as compared to a healthy control sample. Results Adults with clinical BFRBs (n = 26) reported increased sensory sensitivity as compared to persons with subclinical BFRBs (n = 48) and healthy individuals (n = 33). Elevations in sensation avoidance differentiated persons with clinical versus subclinical BFRBs. Sensation seeking patterns were not different between groups. Unexpectedly, BFRB severity was associated with lower registration of sensory stimuli, but this finding may be due to high psychiatric comorbidity rates in the BFRB groups. Conclusions These findings suggest that several sensory abnormalities may underlie BFRBs. Implications for the etiology and treatment of BFRBs are discussed

Emotion Regulation Deficits in Persons with Body-Focused Repetitive Behavior Disorders

Background Conceptualizations of emotion dysregulation (ED) and body-focused repetitive behavior disorders (BFRBDs) imply that ED may be a central component of BFRBDs as well as a factor that distinguishes BFRBDs from non-impairing, subclinical body-focused repetitive behaviors (BFRBs). The current study empirically tested these observations. Methods One hundred thirty-eight undergraduates (of 1900 who completed a screening survey) completed self-report measures assessing four emotion regulation (ER) deficits hypothesized to underlie ED (alexithymia, maladaptive emotional reactivity, experiential avoidance, and response inhibition when distressed); 34 of these participants had BFRBDs, 64 had subclinical BFRBs, and 42 were unaffected by BFRBs. Results Results indicated that participants with BFRBDs reported higher levels of maladaptive emotional reactivity, experiential avoidance, and response inhibition when distressed than participants with subclinical BFRBs and participants unaffected by BFRBs. These results held even when controlling for comorbidity and total number of reported BFRBs. Participants did not differ on alexithymia. Limitations Limitations of the current study include the BFRB groups’ different distributions of BFRB types (e.g., hair pulling versus skin picking), the sample\u27s demographic uniformity, and the fact that negative affectivity was not controlled when exploring BFRB group differences on ER deficits. Future research should improve on these limitations. Conclusions The current results suggest that ED is a factor that differentiates BFRBDs from subclinical BFRBs. Such results may be useful for generating hypotheses regarding mechanisms responsible for BFRBs’ development into BFRBDs. Furthermore, these results may provide insight into factors that explain the efficacy of more contemporary behavioral treatments for BFRBDs

Possible Subclinical Leaflet Thrombosis in Bioprosthetic Aortic Valves

To the Editor: Makkar et al. (Nov. 19 issue)(1) report possible subclinical leaflet thrombosis in up to 40% of patients involved in a clinical trial of transcatheter aortic-valve replacement (TAVR). In contrast, we found a relatively low incidence (7%) of possible subclinical valve leaflet thrombosis among patients in our series in which 255 patients underwent TAVR with the use of a CoreValve prosthesis. A retrospective review of our series (unpublished data) showed that in 104 patients, cardiac computed tomography (CT) at a median of 7 days after implantation (range, 3 to 87) (in 51 patients), transesophageal echocardiography at a median . . 

Helminth infections: do they affect the productive efficiency of speacialised dairy farms?

Subclinical infections with gastrointestinal (GI) nematodes and liver fluke are an important cause of production losses in grazing dairy cattle

The Clinical Significance of Subclinical Thyroid Dysfunction.

Subclinical thyroid disease (SCTD) is defined as serum free T(4) and free T(3) levels within their respective reference ranges in the presence of abnormal serum TSH levels. SCTD is being diagnosed more frequently in clinical practice in young and middle-aged people as well as in the elderly. However, the clinical significance of subclinical thyroid dysfunction is much debated. Subclinical hyper- and hypothyroidism can have repercussions on the cardiovascular system and bone, as well as on other organs and systems. However, the treatment and management of SCTD and population screening are controversial despite the potential risk of progression to overt disease, and there is no consensus on the thyroid hormone and thyrotropin cutoff values at which treatment should be contemplated. Opinions differ regarding tissue effects, symptoms, signs, and cardiovascular risk. Here, we critically review the data on the prevalence and progression of SCTD, its tissue effects, and its prognostic implications. We also examine the mechanisms underlying tissue alterations in SCTD and the effects of replacement therapy on progression and tissue parameters. Lastly, we address the issue of the need to treat slight thyroid hormone deficiency or excess in relation to the patient's ag

Review of the risks and/or benefits of thyroxine treatment in ‘mild’ subclinical hypothyroidism

Subclinical hypothyroidism (SCH) is a form of mild thyroid failure and is a commonly encountered condition in clinical practice. It denotes the presence of a raised serum thyroid stimulating hormone (TSH) and normal serum free thyroid hormone concentrations (tri-iodothyronine [T3] and thyroxine [T4]). ‘Mild’ subclinical hypothyroidism is associated with a TSH level between 4.5-9mIU/L (0.4-4.2) whereas patients with a serum TSH level ?10mIU/L are classified as having the ‘severe’ form. The clinical significance of this condition has aroused a lot of interest over the last decade, especially its effects on various health outcomes (namely cardiovascular disease, lipid metabolism, fertility, pregnancy outcomes and fetal neurocognitive function). Unfortunately the unavailability of adequately powered, double-blind randomised controlled studies precludes the availability of clear cut guidelines as to how one should treat subclinical hypothyroidism. This review looks at the available evidence for and against treatment of SCH with levothyroixine. Most authors agree on the use of clinical judgement as well as individualising management based on the underlying unique patient characteristics when it comes to formulating a management plan for this condition.peer-reviewe