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PubMedDate not supplied

Community health indicators predicting adolescent academic achievement.

Throughout the literature investigating adolescent academic achievement, little or no attention has been focused on indicators of community health as factors that share variance with academic achievement. The purpose of this study was to conduct exploratory analyses using indicators of community health to investigate adolescent academic achievement. This study employed hierarchical linear multiple regression to explain variations in adolescent academic achievement as measured by standardized tests for two different school years. The unit of analyses was the school district with the standardized test results of 8th grade students as academic achievement. The first model of the school district for school year 1997-98 accounted for almost 58% of the variance in adolescent academic achievement. This model was replicated on a different school year and it accounted for almost 63% of the variance in adolescent academic achievement. These strong models hold great promise for future investigations of adolescent academic achievement using indicators of community health and other community contextual variables.

Adolescent↗

PubMed1995

Determinants of fetal haemoglobin in newborn infants.

Percentage fetal haemoglobins (% HbF) were measured in 7081 newborns at the University Hospital, Nottingham, between 1990 and 1992 to assess the effects of a range of factors, and to determine if there was an association between % HbF at birth and risk of SIDS (sudden infant death syndrome). Data from the obstetric clinical records were analysed by multiple linear regression to establish the major determinants of % HbF. New findings were the identification of maternal smoking, twin pregnancy, ethnic origin, and season of birth as significant determinants. Alcohol use, drug and vitamin intake, and duration of labour were not found to be important. The previously reported correlations between % HbF and sex, gestational age, and birthweight were confirmed, and the relative effects quantified. Overall, the major determinants of an increase in % HbF in neonates are similar to the known antenatal risk factors for sudden infant death syndrome (SIDS).

Birth Weight↗

PubMed2000

A prospective investigation of dispositional optimism as a predictor of health-related quality of life in head and neck cancer patients.

The aim of this study was to investigate the role of dispositional optimism (DO) as a predictor of health-related quality of life (HRQL) in a sample of upper aerodigestive tract cancer (UADT) patients. A prospective observational study design was used with a cohort of patients from one centre. DO was evaluated using a French version of the Life Orientation Test (the FLOT) translated and validated for this study. HRQL was evaluated using the EORTC QLQ-C30 prior to and 3 months following treatment. The association between FLOT ratings and HRQL was evaluated using linear multiple regression analysis and a two-way ANOVA with repeated measures. Baseline data were gathered on 101 subjects and follow-up data on 88 of these. The sample was dichotomized around the median FLOT score creating 'optimist' and 'pessimist' groups. Before treatment, optimists reported better role, cognitive and emotional function, less pain and fatigue and a better global rating of HRQL than did pessimists. Following treatment, optimists reported better role and cognitive functioning, less pain and better global HRQL than did pessimists. Pessimists reported a greater deterioration in the role domain following treatment than did optimists. At no point did pessimists rate HRQL better than optimists. The results suggest that optimism is associated with better HRQL in French UADT cancer patients.

Analysis of Variance↗

PubMed1992

Is age an independent predictor of early and late mortality in patients with acute myocardial infarction?

PURPOSE: To determine whether advancing age is an independent predictor of increased mortality following acute myocardial infarction or simply a marker for more extensive cardiac disease, a higher prevalence of comorbid conditions, and/or differences in therapeutic approach. PATIENTS: A total of 261 consecutive patients with documented acute myocardial infarction admitted to a university teaching hospital during a 1-year interval. METHODS: Seventy-four variables were analyzed to determine univariate predictors of inhospital and 1-year post-discharge mortality. Multiple linear regression models were constructed to determine independent predictors of early and late mortality after adjusting for baseline and therapeutic differences between younger and older patients. RESULTS: Compared with patients less than 70 years (n = 124), patients greater than or equal to 70 years (n = 137) were more likely (all p less than 0.05) to be female and have a prior history of ischemic heart disease. New York Heart Association functional class and Killip class on admission were higher in older patients, as were the admission serum creatinine and blood urea nitrogen levels. Serum albumin and peak creatine kinase levels were lower in older patients, but older patients were more likely to exhibit left ventricular hypertrophy or atrioventricular block on the initial electrocardiogram. Finally, younger patients were three times as likely to receive a thrombolytic agent and 66% more likely to receive intravenous beta-blockade than older patients, and younger patients were also more likely to receive heparin and intravenous nitroglycerin. Hospital mortality was 5.6% in patients less than 70 years versus 16.1% in patients greater than or equal to 70 years (p = 0.013). After adjusting for baseline and therapeutic differences, independent predictors of hospital mortality were systolic blood pressure on admission (inverse correlation, p = 0.0095), beta-blocker therapy (inverse correlation, p = 0.01), age (p = 0.014), peak creatine kinase level (p = 0.015), and Killip class (p = 0.035). Among hospital survivors, 1-year post discharge mortality was 6.8% in patients less than 70 years versus 19.1% in those greater than or equal to 70 years (p = 0.001). Independent predictors of post-discharge mortality after adjusting for age-related baseline and therapeutic differences were admission heart rate (p = 0.0004), age (p = 0.011), left ventricular ejection fraction (inverse correlation, p = 0.012), initial non-Q-wave myocardial infarction (p = 0.026), and the blood urea nitrogen level (p = 0.036). CONCLUSION: After adjusting for multiple baseline and therapeutic differences between older and younger patients, age per se remains a strong independent predictor of both inhospital and 1-year post-discharge mortality rates in patients with acute myocardial infarction.

Age Factors↗

PubMed1999

Hormone replacement therapy affects body composition and leptin differently in obese and non-obese postmenopausal women.

Leptin and oestrogen are both involved in the regulation of adipose tissue deposition and feeding behaviour. We investigated whether 5 years of hormone replacement therapy (HRT) affected serum leptin and body composition differently in 89 postmenopausal women treated with HRT compared with 178 controls. At baseline, leptin was significantly correlated with oestradiol (r=0.13, P<0.05) and in multiple backward regression analysis including oestradiol and any estimate of body fat, oestradiol remained a significant determinant of leptin levels. In the control group, all estimates of body fat determined by dual energy X-ray absorptiometry (DEXA) or anthropometry were increased (3.6-16.9%) and leptin increased 31.3% (16.03+/-1.02 to 20.84+/-1.2 ng/ml (s.e.m.), P<0.001). In the HRT group all estimates of body composition also increased during the 5-year observation but to a lesser extent than observed in the control group (1.0-8.5%). Leptin was raised by 19.7% (17.81+/-1.32 to 20.57+/-1.65 ng/ml, P<0.001). However, the DEXA scans revealed that the control group gained 2.4-fold more fat during the 5-year observation (1.9+/-0.3 vs 0.8+/-0.4 kg, P<0.05), and especially the trunk fat increased (1.4+/-0.2 vs 0.7+/-0.3 kg, P<0.05). This was reflected in the increase in leptin levels, which were increased by 7.4% in the control group compared with the HRT group (4.81+/-0.60 vs 2.76+/-0.87 ng/ml, P<0.05). Adjusting for the difference in adipose tissue revealed that HRT had no independent effect on leptin levels. Comparisons between obese (body mass index>25 kg/m(2)) and non-obese (<25 kg/m(2)) subjects by stratifying for HRT treatment using multiple linear regression revealed that the change in fat mass was significantly less among treated subjects (P=0.038) and especially in the non-obese subjects (P=0.001). The change in trunk fat was similarly correlated with treatment status (P=0.029) and with the degree of obesity (P=0.006). In conclusion, 5 years of HRT treatment significantly reduced fat mass accumulation, especially in the trunk region. This effect of HRT was more pronounced in non-obese as compared with obese subjects. The HRT-induced reduction in fat mass seems not to be mediated by leptin.

Body Composition↗

PubMed2000

Variation in caries and treatment experience in 35-44-year-old Lithuanians.

Data summarising caries levels differ between countries and often conceal large variations. These differences may reflect variations at individual, group, social and other levels. Caries and treatment experience differences are found to be significantly related to a variety of clinical and non-clinical factors. Variation in caries within Lithuanian children has been reported and related to background-, behavior-, dental care- and other factors. Variation in general or related to any factors in adult Lithuanian population has not been studied. The aim of the present study was to estimate variation in caries and treatment experience and relate them to biological-, psychosocial-, health-related, behavioral- and dental care related aspects. The existing knowledge from other oral health studies was used to select the factors found of importance in relation to variations in caries scores. The study consisted of clinical and self-reported data collected from a stratified random sample of 382 individuals (attendance rate 50%). Two statistical approaches, a bivariate and a multivariate, were applied. The two dependent variables DMFT and DS were tested with a set of independent variables. The bivariate analysis revealed significant associations for approximately one half of all variables studied. For multivariate testing, a backward linear multiple regression was used. Forty-one percent of the variation in DS was explained and 48% in DMFT scores. Differences in scores were related to various factors in the two analyses. The strength and significance of a few relationships differed in both of the analyses. The multivariate testing revealed some strong and significant associations with independent variables which were found to be weak and non-significant (P>0.05) when tested bivariately and vice versa. Less than half of the variation could be explained in dental caries scores in 35-44-year-olds and not only dental care related factors were important. In both of the analyses, the varying degrees of strength (significance levels) give rise to a hypothesis that this incomplete explanation of the variation can be due to interrelated effects of different estimates.

Adult↗

PubMed2004

Health-related quality of life (HRQoL) in patients with cancer and other concurrent illnesses.

This study analyzed the impact of eight common chronic medical conditions on cancer patients' health-related quality of life (HRQoL) as measured by the functional living index-cancer (FLIC). The FLIC was administered to a population of 405 people in 14 communities in the North Central US within 4-8 weeks of diagnosis with breast or colorectal cancer. At that time, patients also self-reported any other health conditions for which they had been receiving medical treatment. The impact of the selected chronic conditions on the FLIC scores was analyzed using Student's t-tests and linear multiple regression. In the bivariate analysis, patients with heart/circulation problems had lower FLIC total scores (p < 0.05), physical well-being subscale scores (p < 0.05), and nausea subscale scores (p < 0.01). Patients with diabetes had lower nausea subscale scores (p < 0.05). The social well-being subscale score was higher with the report of arthritis/joint problems (p = 0.001). In multivariate analysis adjusted for age, arthritis/joint problems were predictive of the social well-being (p < 0.01) and hardship due to cancer (p < 0.05) subscale scores; heart/circulation problems (p < 0.001) and diabetes were predictive of the nausea subscale scores. ECOG performance status was significant predictor for the FLIC total and all of the subscale scores. HRQoL as measured with the FLIC scores in patients with cancer is impacted by the presence of other concurrent health conditions; this finding has implications for HRQoL theory and application.

Aged↗

PubMed1996

US childhood mortality, 1950 through 1993: Trends and socioeconomic diffferentials.

OBJECTIVES: This study examined trends and differentials in US childhood mortality from 1950 through 1993 according to sex, race/ethnicity, education, family income, and cause of death. METHODS: Log-linear, multiple regression, and Cox proportional hazards regression models were applied to the data from the National Vital Statistics System, the National Longitudinal Mortality Study, and the Area Resource File. RESULTS: Substantial declines in US childhood mortality have occurred in the past 4 decades, primarily due to decreases in mortality from unintentional injuries, cancer, pneumonia and influenza, and congenital anomalies. The overall declining trend, however, has been dampened by a twofold to threefold increase in the suicide and homicide rates among children since 1968. Male, Black, American Indian, Hawaiian, and Puerto Rican children and those in the lower socioeconomic strata were at an increased risk of death. CONCLUSIONS: Increasing trends in mortality from violence, firearm injuries, and human immunodeficiency virus/acquired immunodeficiency syndrome pose a major obstacle to continued declines in US childhood mortality. Reducing socioeconomic disparities and improving access to and use of health care may bring about further declines in overall and injury-related childhood mortality.

Adolescent↗

PubMed2002

Brain atrophy in multiple sclerosis: impact of lesions and of damage of whole brain tissue.

INTRODUCTION: In multiple sclerosis (MS), brain atrophy measurement on magnetic resonance imaging (MRI) reflects overall tissue loss, especially demyelination and axonal loss. We studied which factor contributes most to the development of brain atrophy extent and severity of lesions or damage of whole brain issue (WBT). METHODS: Eighty-six patients with MS [32 primary progressive (PP), 32 secondary progressive (SP)] and 22 relapsing-remitting (RR) were studied MRI included T1- and T2-weighted imaging to obtain hypointense T1 lesion volume (T1LV) and two brain volume measurements: 1) the parenchymal fraction (PF; whole brain parenchymal volume/intracranial volume) as a marker of overall brain volume, and 2) the ventricular fraction (VF; ventricular volume/intracranial volume) as a marker of central atrophy. From magnetization transfer ratio (MTR) histograms, the relative peak height (rHp) was derived as an index of damage of WBT (a lower peak height reflects damage of WBT). RESULTS: Multiple linear regression analysis revealed that damage of WBT explains most of the variance of PF (standardized coeffcient beta = 0.59, p < 0.001 for WBT and beta = -0.19, p < 0.05 for T1LV). These findings are independent of disease phase; even in RR patients, damage of WBT plays a dominant role in explaining the variance in overall brain volume. By contrast the variance in VF is explained by both T1LV and damage of WBT (standardized coefficient beta = 0.43, p < 0.001 for T1LV and beta =-0.38, p < 0.001 for WBT). CONCLUSION: This study shows that overall brain volume (PF) is best explained by damage of WBT, supporting the significance of nonfocal pathology in MS in producing tissue loss. Central atrophy (VP) is determined by both lesion volume and damage of WBT. Our results underline the importance of nonfocal pathology even in the early (RR) phase of the disease.

Adult↗

PubMed2001

The predictive parameters of erythropoietin hyporesponsiveness in patients on continuous ambulatory peritoneal dialysis.

BACKGROUND: The present study was aimed at investigating the predictive parameters of erythropoietin (epoetin) hyporesponsiveness in patients on continuous ambulatory peritoneal dialysis (CAPD). METHODS: We studied 40 patients with end-stage renal disease who had been receiving CAPD for at least 6 months and epoetin therapy for at least more than 2 months. Pearson's simple correlation and multiple stepwise linear regression analysis was used to discover what parameter can predict epoetin resistance. We expressed epoetin resistance index (ERI) as weekly epoetin dose/hematocrit/body weight'. The dose of epoetin is titrated by about 25% every 2 to 4 weeks to maintain a target hematocrit level between 33% and 36%. RESULTS: We analyzed the relationship between ERI and other predictive parameters by Pearson's correlation. These results showed ERI has a statistically significant correlation with transferrin saturation (TS) (r = -0.327, p = 0.042), total weekly Kt/Vurea (r = -0.423, p = 0.018), serum albumin level (r = -0.458, p = 0.003), normalized protein catabolic rate (nPCR) (r = -0.479, p = 0.006), normalized protein equivalent of total nitrogen appearance (nPNA) (r = -0.488, p = 0.005) and serum C-reactive protein (CRP) (r = 0.332, p = 0.036). Regression analysis was performed using stepwise linear regression for multiple variables to discover the most independent variable which is correlated with ERI. ERI was entered as a dependent variable, whereas the other parameters (age, duration of peritoneal dialysis, serum albumin level, CRP, serum ferritin, total weekly Kt/Vurea, nPCR, nPNA, serum iPTH, serum aluminium, TS) were entered as independent variables. This analysis showed CRP is the most significant variable and, if CRP is excluded, nPNA is the significant variable. CRP has a statistically significant correlation with serum albumin level (r = -0.418, p = 0.007) and total weekly Kt/Vurea (r = -0.366, p = 0.043). High CRP group has more increased level of ERI (p < 0.05), age (p < 0.05) and serum creatinine level (p < 0.05) than normal control, but more decreased level of serum albumin (p < 0.01) and serum iron levels (p < 0.05). CONCLUSION: These results indicate that CRP is the most important predictor of epoetin hyporesponsiveness.

Adult↗

PubMed1991

Effects of intoxication on the catecholamine response to multisystem injury.

In patients suffering isolated head trauma, we have previously shown that levels of circulating catecholamines obtained within 48 hours of trauma correlate with the severity of brain injury and predict outcome and that intoxication blunts this response. The effects of alcohol on the increase in catecholamines in systematically injured patients, however, have not been well defined. From 1983 to 1990, 78 patients (74% male; median age 30 years) with blunt head and multisystem injury, who also had alcohol levels measured within 5 hours of injury, were studied. Norepinephrine and epinephrine levels were assayed by a radioenzymatic technique. Injury severity was assessed by the admission Glasgow Coma Scale (GCS) score (4-15; median, 12), the Injury Severity Score (ISS) (13-50; median, 25) and the volume of blood products administered within the first 24 hours (0-14.4 L; median, 0.5 L). The impact of alcohol on the norepinephrine response to injury was analyzed using multiple linear regression models, including polynomial interaction terms. Norepinephrine levels significantly (p less than 0.0001) correlated with the GCS score and ISS. However, alcohol significantly lowered the norepinephrine response to decreasing GCS score (R = 0.49, p less than 0.002) and to increasing ISS (R = 0.51, p less than 0.0006). The blunting of the catecholamine response was most marked in those severely injured. The rise in norepinephrine concentrations seen with increasing volume of blood replacement was not affected by intoxication. An association between injury severity and epinephrine levels was also present, but not as consistently. Epinephrine concentrations rose with falling GCS score and with increasing ISS values, but unlike norepinephrine, there were no apparent effects of alcohol on changes in epinephrine levels. Thus, in patients suffering head and multisystem injury, catecholamine changes reflect the severity of injury using three different scalers. Furthermore, intoxication blunts only the norepinephrine component of this important biologic response.

Adolescent↗

PubMed2003

Mortality after reamed intramedullary nailing of bilateral femur fractures.

We performed retrospective review of 743 patients treated with reamed intramedullary nailing of a femoral shaft fracture was done to assess the clinical impact of bilateral femur fractures on the mortality, hospital stay, and length of intensive care treatment in patients with blunt trauma. Unilateral injuries occurred in 689 patients and bilateral injuries occurred in 54 patients. Mortality in patients with bilateral femur fractures was 5.6% compared with 1.5% in patients with unilateral femur fractures. The two groups were analyzed using multiple linear regression and logistic regression with age and Injury Severity Scores as covariants to allow for comparison of similarly injured groups as predicted by the Injury Severity Scores. Bilateral femur fractures still were associated with a significantly higher mortality, longer length of stay in the hospital, and longer length of stay in the intensive care unit. As expected, when analyzed separately, patients with bilateral femur fractures had significantly higher Injury Severity Scores, longer lengths of stay in the intensive care unit, and longer lengths of stay in the hospital. Patients with bilateral femur fractures have an increased mortality when compared with patients with unilateral femur fractures after controlling for Injury Severity Score and age. When used alone, the Injury Severity Score underestimates the contribution of a second femur fracture.

Adolescent↗

PubMedDate not supplied

[Health Search--Research Institute of the Italian Society of General Practice: the creation of a research database in general practice].

OBJECTIVE: To describe a database used in general practice by analysing the characteristics of the physicians providing the data and the completeness of the data recording on the basis of the indicators of interest (smoking habits, weight, height, and the prevalence of hypertension). DESIGN: Descriptive study and multiple linear regression analysis of the relationships between structural variables and outcomes. SETTING: General practitioners (GPs) belonging to the Italian Society of General Medicine (SIMG), and enrolled in Health Search (HS). POPULATION: Six hundred and ninety-five voluntarily enrolled GPs and their patients. PRINCIPAL OUTCOMES: Descriptive statistics (mean and median values, standard deviation, frequencies) concerning the general characteristics of the GPs, the ways in which they connect to the network and their use of the clinical data management software, and epidemiological measures concerning the prevalence of hypertension among their patients, and the recording of weight, height and tobacco smoking habits. RESULTS: The geographic distribution of the GPs is homogeneous: 317 in Northern Italy (12.52 physicians per 10(6) patients), 134 in Central Italy (12.30 physicians per 10(6) patients) and 244 in Southern Italy and the Islands (11.89 physicians per 10(6) patients). Five hundred and ninety-five (85.6%) are males; their mean age is 46.7 years (SD +/- 3.8); the mean number of patients per physician is 1128; 69% have at least one post-graduate specialisation; 49% practise alone; and they work for a mean of 30 hours per week (SD +/- 13). Five hundred and fifty-three GPs were actually connected to the network as of January 2003. The data relating to the years 2000-2001 show an increase in the number of connected physicians (34 in 2000 and 261 in 2001) and in the number of connections (a median of 12 in 2000 and 17 in 2001). The GPs contact more than 80% of their patients every year. The frequency of the recording of data concerning smoking habits, weight and height increases in proportion with the frequency of connections. The prevalence of hypertension among the patients included in the survey is 5.4%. Multiple regression analysis showed that the variability in the prevalence of hypertension was not influenced by the frequency of PC use but by the different structure of the age classes of the patients. CONCLUSIONS: This study of the variables relating to GPs, their clinical practices, and their use of computerised records (examined by means of the chosen indicators) shows that the regular and complete recording of the principal data of health interest is feasible insofar as it is not biased by the characteristics of the GPs, and advantageous. The construction of the database therefore represents a first step towards the initiation of routine research into general practice in Italy.

Biomedical Research↗

PubMed2005

Quantitative structure-activity relationship and quantitative structure-pharmacokinetics relationship of 1,4-dihydropyridines and pyridines as multidrug resistance modulators.

PURPOSE: The aim of this study was to develop quantitative structure-activity/pharmacokinetic relationships (QSAR/QSPKR) for a series of synthesized 1,4-dihydropyridines (DHPs) and pyridines as P-glycoprotein (P-gp) inhibitors. METHODS: Molecular descriptors of test compounds were generated by 3D molecular modeling using SYBYL and KowWin programs. Forward inclusion coupled with multiple linear regression (MLR) was used to derive a QSAR equation for Ca2+ channel binding. A multivariate statistical technique, partial least square (PLS) regression, was applied to derive a QSAR model for P-gp inhibition and QSPKR models. Cross-validation using the "leave-one-out" method was performed to evaluate the predictive performance of models. RESULTS: For Ca2+ channel binding, the MLR equation indicated a good correlation between observed and predicted values (R2 = 0.90), and cross-validation confirmed the predictive ability of the model (Q2 = 0.67). For P-gp reversal, the model obtained by PLS could account for most of the variation in P-gp inhibition (R2 = 0.76) with fair predictive performance (Q2 = 0.62). Nine structurally related 1,4-DHP drugs were used for QSPKR analysis. The models could explain the majority of the variation in clearance (R2 = 0.90), and cross-validation confirmed the prediction ability (Q2 = 0.69). CONCLUSION: QSAR/QSPKR models were developed, and the QSAR models were capable of identifying synthesized 1,4-DHPs and pyridines with potent P-gp inhibition and reduced Ca2+ channel binding. The QSPKR models provide insight into the contribution of electronic, steric, and lipophilic factors to the clearance of DHPs.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2006

Whole-brain T1 mapping in multiple sclerosis: global changes of normal-appearing gray and white matter.

PURPOSE: To prospectively investigate whether T1 changes in normal-appearing white matter (WM) and normal-appearing gray matter (GM) in multiple sclerosis (MS) are global or regional and their relationship to disease type. MATERIALS AND METHODS: The institutional ethics review board approved study; written informed consent was obtained. Whole-brain T1 maps were obtained in 67 patients with MS and 24 healthy control subjects with three-dimensional fast low-angle shot flip angle-array method, with correction for B(1) imperfections. Analysis of variance was performed on T1 histogram parameters of global normal-appearing WM and GM. Regional mean T1 values were analyzed with a multilevel approach. Multiple linear regression analysis was performed to investigate associations with clinical disability and overall atrophy. For patients, T2 lesion load was determined. RESULTS: T1 histograms of normal-appearing WM had significantly higher peak positions for patients with MS (792 msec +/- 36 in secondary progressive [SP] MS) than for control subjects (746 msec +/- 23) and were significantly broader and lower (all P < .001). Histograms for cortical normal-appearing GM were significantly shifted (peak positions, 1263 msec +/- 44 in control subjects and 1355 msec +/- 62 in patients with SP MS) (P < .001). Histogram peak positions were significantly higher in SP MS than in relapsing-remitting (RR) and primary progressive MS (P < .05). In SP disease, at least 31% of normal-appearing WM and 20% of cortical normal-appearing GM were affected. In MS, T1 was significantly elevated in all normal-appearing WM and cortical normal-appearing GM regions (all P < .01) but was elevated only in the thalamus in deep GM (P < .05). Cortical T1 histogram peak position was associated with clinical disability; T2 lesion load was not. CONCLUSION: Results suggest that a global disease process affects large parts of both normal-appearing WM and GM in MS and effects are worse for SP MS than for RR MS.

Adult↗

PubMed1998

Serum ferritin as a component of the insulin resistance syndrome.

OBJECTIVE: In epidemiological studies, serum ferritin was the second-strongest determinant of blood glucose (after BMI) in regression models and the third-strongest determinant of serum insulin (after BMI and age). Its concentration also correlated positively with plasma triglycerides and apolipoprotein B concentrations, and negatively with HDL2 cholesterol. We hypothesized that serum ferritin could be a marker of insulin resistance. RESEARCH DESIGN AND METHODS: Oral glucose tolerance and insulin sensitivity (SI, minimal model method) were prospectively evaluated in 36 healthy subjects. The relationship between serum ferritin and metabolic control (as measured by HbA1c levels) was also studied in 76 consecutive NIDDM patients. RESULTS: In healthy subjects, log-transformed serum ferritin (LOGFER) correlated with basal serum glucose (r = 0.44, P = 0.007), but not with BMI, age, systolic or diastolic blood pressure, total cholesterol, VLDL cholesterol, HDL cholesterol, total triglycerides, VLDL triglycerides, serum insulin, or HbA1c (all P = NS). Identical results were obtained when the two lowest quartiles of serum ferritin were evaluated separately. However, in the two highest quartiles, LOGFER correlated with BMI (0.50, P = 0.02), diastolic blood pressure (r = 0.8, P < 0.0001), serum LDL cholesterol (r = 0.57, P = 0.01), VLDL cholesterol (r = 0.48, P = 0.03), total cholesterol and HDL2 and HDL3 subtractions of HDL cholesterol (r = -0.68, -0.76, -0.55, P = 0.001. < 0.0001, and 0.01, respectively), total triglycerides (r = 0.60, P = 0.006), HDL2/HDL3 quotient (P = -0.71, P = 0.001), VLDL triglycerides (r = 0.65, P = 0.004), and serum uric acid (r = 0.51, P = 0.03), but not with systolic blood pressure (r = 0.38, P = 0.15). After adjusting for BMI, only the correlations between LOGFER and diastolic blood pressure (r = 0.7, P = 0.002) and HDL2/HDL3 quotient (r = -0.63, P = 0.01) remained significant. Strong correlations between LOGFER and glucose area under the curve during oral glucose tolerance test (Pearson's r = 0.73, P = 0.001) and SI (r = -0.68, P = 0.001), which remained significant after controlling for BMI, were observed. LOGFER (beta = -0.44, P = 0.01) and BMI (beta = -0.52, P = 0.004) constituted independent predictors of insulin sensitivity in a multivariate analysis (R2 = 0.68). In 76 consecutive NIDDM outpatients, serum glucose (P < 0.00001) and LOGFER (P = 0.03) independently predicted the value of HbA1c (R2 = 0.40) in a multiple linear regression analysis. CONCLUSIONS: The correlations among serum ferritin and diastolic blood pressure, HDL quotient, glucose area under the curve, and SI suggest that serum ferritin could be a marker of the insulin resistance syndrome. Serum ferritin may also be an independent determinant of poor metabolic control in the diabetic patient.

Adult↗

PubMed2006

The effect of conformation on orthopaedic health and performance in a cohort of National Hunt racehorses: preliminary results.

REASONS FOR PERFORMING STUDY: There is a lack of scientific data and studies on the effect of conformation on performance or on orthopaedic health. OBJECTIVES: To investigate the relationship between conformation, injury and performance in racehorses used for racing over fences. METHODS: Over 2 years, 108 National Hunt racehorses were followed and their medical and performance data recorded. Conformation was measured in 3D with a computerised motion analysis system. Linear multiple regression models were used to evaluate the effect of conformation on measures of race performance and stepwise forward logistic regression models to assess the effect on risk of injury. RESULTS: An increase in intermandibular width, flexor angle of the shoulder joint and coxal angle (the angle between the ilium and ischium) was demonstrated to have a positive effect on performance. Performance decreased with increasing girth, length of the hind digit and valgus conformation of the metacarpophalangeal joint. The risk of suffering from superficial digital flexor tendon injury increased with increasing metacarpophalangeal joint angle and with carpus valgus conformation. The risk of pelvic fracture increased with valgus conformation of the tarsus and decreased with an increasing coxal angle. CONCLUSION: Valgus deformation was demonstrated to be detrimental to performance or increased risk of injury, perhaps resulting in higher loads on musculoskeletal structures. The coxal angle was the only parameter to have an effect on both risk of injury and performance. An alignment of the muscles with the axis of the pelvis may be beneficial for force transmission and decrease the bending moment of the muscles on the bones. The statistical power of this study is limited, however it provides preliminary data necessary for the planning of a larger scale study on the effect of conformation on performance and risk of injury. CLINICAL RELEVANCE: Studies of the effects of conformation on performance and risk of injury may aid in identifying individuals likely to perform well on the racecourse and avoid risks of injury.

Animals↗

PubMed2006

Citation advantage of open access articles.

Open access (OA) to the research literature has the potential to accelerate recognition and dissemination of research findings, but its actual effects are controversial. This was a longitudinal bibliometric analysis of a cohort of OA and non-OA articles published between June 8, 2004, and December 20, 2004, in the same journal (PNAS: Proceedings of the National Academy of Sciences). Article characteristics were extracted, and citation data were compared between the two groups at three different points in time: at "quasi-baseline" (December 2004, 0-6 mo after publication), in April 2005 (4-10 mo after publication), and in October 2005 (10-16 mo after publication). Potentially confounding variables, including number of authors, authors' lifetime publication count and impact, submission track, country of corresponding author, funding organization, and discipline, were adjusted for in logistic and linear multiple regression models. A total of 1,492 original research articles were analyzed: 212 (14.2% of all articles) were OA articles paid by the author, and 1,280 (85.8%) were non-OA articles. In April 2005 (mean 206 d after publication), 627 (49.0%) of the non-OA articles versus 78 (36.8%) of the OA articles were not cited (relative risk = 1.3 [95% Confidence Interval: 1.1-1.6]; p = 0.001). 6 mo later (mean 288 d after publication), non-OA articles were still more likely to be uncited (non-OA: 172 [13.6%], OA: 11 [5.2%]; relative risk = 2.6 [1.4-4.7]; p < 0.001). The average number of citations of OA articles was higher compared to non-OA articles (April 2005: 1.5 [SD = 2.5] versus 1.2 [SD = 2.0]; Z = 3.123; p = 0.002; October 2005: 6.4 [SD = 10.4] versus 4.5 [SD = 4.9]; Z = 4.058; p < 0.001). In a logistic regression model, controlling for potential confounders, OA articles compared to non-OA articles remained twice as likely to be cited (odds ratio = 2.1 [1.5-2.9]) in the first 4-10 mo after publication (April 2005), with the odds ratio increasing to 2.9 (1.5-5.5) 10-16 mo after publication (October 2005). Articles published as an immediate OA article on the journal site have higher impact than self-archived or otherwise openly accessible OA articles. We found strong evidence that, even in a journal that is widely available in research libraries, OA articles are more immediately recognized and cited by peers than non-OA articles published in the same journal. OA is likely to benefit science by accelerating dissemination and uptake of research findings.

Bibliometrics↗