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PubMedDate not supplied

Lung volumes in healthy nonsmoking adults.

Total lung capacity (TLC), functional residual capacity, residual volume, and corresponding 95% confidence intervals were measured in 245 healthy nonsmoking person (122 women, 123 men) using a single-breath helium technique. Prediction equations for lung volumes were generated by multiple linear regression. The resultant equations are similar to previously published equations using multiple-breath gas equilibration techniques. Measured 95% confidence intervals can be closely approximated by using two times the standard error of the estimate for each equation, but cannot be approximated by using +/- 20% of the predicted value. Radiographic TLC was not significantly different from the helium dilution TLC.

Adult↗

PubMed2006

Quantitative structure spectroscopy relationships of carbon-13 nuclear magnetic resonance chemical shifts of steroids.

Quantitative structure spectroscopy relationships (QSSRs) are systematically studied for carbon-13 nuclear magnetic resonance ((13)C NMR) spectroscopic simulation of steroid compounds. Both the atomic electronegativity interaction vector (AEIV) and the atomic hybridization state index (AHSI) are used for the expression of local chemical microenvironment and atomic hybridization state of 4434 resonance carbon atoms in 203 steroid molecules. A multiple linear regression (MLR) model is built after screening some insignificant parameters with the stepwise multiple regression (SMR) technique. Correlation coefficients of the developed model are R(cum)(2)=0.9341 and Q(LOO)(2)=0.9336 for classical estimation of molecular modeling and the cross-validation with leave-one-out (LOO) procedures, respectively, primarily indicating that the MLR model has good modeling stability and prediction ability. Furthermore, the superior performance of the MLR model is tested by the leave-33%-out (L33%O) cross-validation method, where the mean correlation coefficients of three test sets are Q(2)=0.9310 and Q(ext)(2)=0.9196 for both internal and external sets. In conclusion, AEIV and AHSI descriptors can be used for estimating and predicting (13)C NMR chemical shifts of steroids.

Carbon Isotopes↗

PubMed2003

[Age determination by radiographic feature of thyroid cartilage in female Han population].

OBJECTIVE: To seek a method of age determination. METHODS: This sample consists of 69 female Chinese han individuals whose ages been known. Five positions were selected from their radiograms which have been divided into three or six grade and then set up a mathematical model to deduce age by multiple linear regression analysis. RESULTS: The standard deviation of female thyroid cartilage is 1.969 and the multiple correctation coefficient is 0.984. CONCLUSION: The observation proved that age determination by radiographic feature of thyroid cartilage can be used for female Chinese han population from 18 to 60 years old.

Adolescent↗

PubMed2006

A new formula for correction of total calcium level into ionized serum calcium values in very elderly hospitalized patients.

Ionized calcium (Ca(2+)) seems to be the best measure of active serum calcium but, in France, numerous laboratories do not have Ca(2+) analyzers so that numerous clinicians use Payne's formula to obtain adjusted calcium (Ca(Ad)) values. In frail very elderly patients with protein/energetic malnutrition and very low concentrations of albumin, "correction" with Payne's formula usually gives false hypercalcemic results, so that hypocalcemia may be seriously underdiagnosed. Two hundred and ninety-four patients of 80 years and older with serum albumin level < 35 g/l were included in four French hospitals for elderly people. Biological measurements were standardized in order to determine Ca(2+) and total calcium (Ca(T)) in accordance with approved guidelines. Ca(Ad) was calculated with Payne's formula whereas the dependence of Ca(2+) with serum protein, albumin and Ca(Ad) was investigated by linear regression, the goodness-of-fit of each equation with the measure of Ca(2+) being studied. Taking into account serum protein and albumin levels, multiple linear regression gave the equation: Ca(2+) (mmol/l)=0.188-0.00469 protein (g/l)+0.0110 albumin (g/l)+0.401 Ca(Ad) with r(2)=0.442. The relative difference between the measure and the value given by the equation did not depend upon the center, and the correlation between measured and computed values of Ca(2+) was better, for any group, with our formula than with Payne's formula. When Ca(2+) was expressed with Ca(T) instead of Ca(Ad), albumin term was no longer significant and the new equation was: Ca(2+) (mmol/l)=0.592-0.00449 protein (g/l)+0.410 total calcium (mmol/l) with r(2)=0.438. We propose an alternative to direct measurement of Ca(2+) with a simple formula usable in geriatric units, which are often deprived of high-performance equipment.

Aged, 80 and over↗

PubMed2000

Invisible nursing: exploring health outcomes at a global level. Relationships between infant and under-5 mortality rates and the distribution of health professionals, GNP per capita, and female literacy.

AIMS: To explore the relationship between the global distribution of health professionals (physicians and nurses), gross national product per capita (GNP), female literacy and the health outcome indicators of infant, and under-5 mortality rates using available data from United Nations' (UN) sources. To consider the reliability and validity of the variables included, and the implications of the findings for health policy and practice, and for further research. DESIGN: Using a database on 155 countries, regression analyses were performed using GNP, female literacy, numbers of physicians per 1000 population and numbers of nurses per 1000 population as independent variables, and infant mortality (IMR) and under-5 mortality rates (u5MR) as dependent variables. RESULTS: Linear regression analyses give R2 values for the two mortality indicators (IMR and u5MR) of 63% and 66% for physicians and 51% and 52% for nurses. Multiple linear regression analyses reveal a more complex picture. Countries with high ratios of physicians and nurses to population relative to their GNP also tend to show low IMRs and u5MRs. However, when female literacy is included in the model, the majority of these outlying countries move back towards the regression line. Nurses disappear from the model altogether when regressed with physicians, GNP per capita and female literacy for both outcome indicators. CONCLUSIONS: Despite the acknowledged need for caution in the validity and reliability of the UN data sources used in the analyses, interesting positive relationships are identified between the input variables and mortality outputs. The implications for future health policy, practice and research are considered. These include the need for more reliable, comprehensive and up-to-date data sets.

Child, Preschool↗

PubMed2001

Relation between initial blood distribution volume and propofol induction dose requirement.

BACKGROUND: Propofol induction dose is variable and depends on many factors, including initial volume of distribution and early disposition. The authors hypothesized that preadministration blood distribution volumes, cardiac output (CO), and hepatic blood flow (HBF) could be examined to establish a propofol induction dose. METHODS: Propofol dose required to reach loss of consciousness, when infused at infusion rate per lean body mass (LBM) of 40 mg x kg(-1) x h(-1), was determined in 75 patients aged 11-85 yr. CO, blood volume (BV), central blood volume (CBV), and HBF were measured with indocyanine green pulse spectrophotometry. Univariate least squares linear regression analysis was used to individually analyze the relation between propofol induction dose and patient characteristics, including LBM, baseline distribution volumes, CO, and HBF. Stepwise multiple linear regression models were used to select important predictors of induction dose. RESULTS: Although there was a significant correlation between the induction dose and each of the eight variables of age, sex, LBM, hemoglobin, CO, BV, CBV, and HBF, only factors of age (partial r = -0.655), LBM (partial r = 0.325), CBV (partial r = 0.540), and HBF (partial r = 0.357) were independently associated with the induction dose (R2 = 0.85) when all variables were included in a multivariate model. CONCLUSIONS: At a constant propofol infusion rate of 40 mg x kg(-1) x h(-1) as a function of LBM in patients with American Society of Anesthesiologists physical status I or II, the induction dose can be determined from four variables: age, LBM, CBV, and HBF.

Adolescent↗

PubMed2006

Exploration of linear modelling techniques and their combination with multivariate adaptive regression splines to predict gastro-intestinal absorption of drugs.

In general, linear modelling techniques such as multiple linear regression (MLR), principal component regression (PCR) and partial least squares (PLS), are used to model QSAR data. This type of data can be very complex and linear modelling techniques often model only a limited part of the information captured in the data. In this study, it was tried to combine linear techniques with the flexible non-linear technique multivariate adaptive regression splines (MARS). Models were built using an MLR model, combined with either a stepwise procedure or a genetic algorithm for variable selection, a PCR model or a PLS model as starting points for the MARS algorithm. The descriptive and predictive power of the models was evaluated in a QSAR context and compared to the performances of the individual linear models and the single MARS model. In general, the combined methods resulted in significant improvements compared to the linear models and can be considered valuable techniques in modelling complex QSAR data. For the used data set the best model was obtained using a combination of PLS and MARS. This combination resulted in a model with a Pearson correlation coefficient of 0.90 and a cross-validation error, evaluated with 10-fold cross-validation of 9.9%, pointing at good descriptive and high predictive properties.

Algorithms↗

PubMed1999

The relationship between hospital volume and outcomes of hepatic resection for hepatocellular carcinoma.

BACKGROUND: Volume-outcome relations have been established for several complex therapies. However, few studies have examined volume-outcome relations for high-risk procedures in general surgery, such as hepatectomy for hepatocellular carcinoma (HCC). OBJECTIVE: To evaluate the relation between hospital volume and outcome for patients undergoing hepatectomy for HCC. DESIGN: Retrospective cohort study. SETTING: All acute-care hospitals in California. PATIENTS: Hospital discharge data were analyzed for each patient in California who underwent major hepatic resection for HCC from January 1, 1990, through December 31, 1994. Hospitals were grouped according to number of hepatectomies performed at each center during the 5-year study. MAIN OUTCOME MEASURES: Outcome measures included operative mortality and length of hospital stay. Regression analyses were used to adjust for differences in patient mix. RESULTS: Five hundred seven patients underwent hepatectomy for HCC during the study. Hepatic resections were performed in 138 hospitals, with an overall in-hospital mortality rate of 14.8%. Three quarters of patients were treated at hospitals that average 3 or fewer hepatic resections for HCC per year. These low-volume providers represent 97.1% of all hospitals treating patients with HCC statewide. Significant reductions in risk-adjusted operative mortality rates (22.7%-9.4%; P = .002, multiple logistic regression) and risk-adjusted length of stay (14.3-11.3 days; P = .03, multiple linear regression) were observed as hospital volume increased. CONCLUSIONS: Low operative mortality and length of stay were associated with high-volume centers. These data support regionalization of high-risk procedures in general surgery, such as hepatectomy for HCC.

Adult↗

PubMed1994

Dehydroepiandrosterone sulphate and bone mineral density.

Several series of data suggest that alterations in adrenal androgen output might be a contributing factor to changes in bone mass. To study the possible relationship between bone density and serum levels of dehydroepiandrosterone sulphate (DHEAS) we investigated 105 women (aged 45-69 years; 76 postmenopausal, 29 perimenopausal). The patients were divided into two groups according to the bone mineral density (BMD) measurement (normal density n = 50, low density n = 55). BMD was measured by dual-energy X-ray absorptiometry of the lumbar spine and femoral neck. Bone mineral content (BMC) of the radius midshaft was measured by single photon absorptiometry. Serum DHEAS level was significantly lower in the 'low density' group than in the 'normal' one (1.91 +/- 1.04 v 4.77 +/- 2.03 mumol/l, p < 0.001). The serum DHEAS level decreased significantly with age in both groups (r = 0.43, p < 0.001 in the 'normal' group; r = 0.35, p < 0.01 in the 'low density' group). Unlike the slopes, the positions of the regression lines differed significantly (difference 2.85 mumol/l, p < 0.001). Correcting for age by multiple linear regression we established a significant positive relationship between DHEAS and BMD of the lumbar spine and femoral neck, and BMC of radius midshaft as well. Since there was no significant difference between the two groups regarding oestrogens, we suggest that DHEAS may have a non-oestrogenic effect on bone. The odds ratio of a subject with a low (< 3.3 mumol/l) serum DHEAS level having low BMD was 40 (confidence interval 13-126).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

PubMed1987

Pharmacodynamics of 3-hydroxyquinidine alone and in combination with quinidine in healthy persons.

The relation between serum concentration of 3-hydroxyquinidine (3-OHQ), a major metabolite of quinidine in humans, and the pharmacologic effect alone and in combination with the parent drug was studied. The heart rate-corrected, computer-averaged QT interval (QTc) was used as the pharmacologic endpoint. In a randomized, double-blind study, 5 healthy subjects received, on 3 separate days 1 week apart, either (1) 300 to 400 mg 3-OHQ orally or (2) 150 mg quinidine base intravenously or (3) a combination in the same doses. Blood samples and electrocardiographic recordings were obtained over the following 10 hours. Serum concentrations of 3-OHQ and quinidine were determined by high-pressure liquid chromatography and the free fraction by ultrafiltration. Peak concentrations of 3-OHQ varied between 1,362 and 3,480 ng/ml after oral 3-OHQ ingestion, but were negligible after intravenous quinidine infusion. The free fraction was 49% +/- 4.8 (mean +/- standard deviation) for 3-OHQ and 20% +/- 4.3 for quinidine. In all 5 subjects a statistically significant correlation was found between serum concentration and QTc prolongation for both quinidine and 3-OHQ (largest p value less than 0.025). The mean slope of the regression line was 0.0184 +/- 0.0128 for 3-OHQ and 0.0297 +/- 0.0111 for quinidine. Multiple linear regression revealed in each subject a significant additive effect of 3-OHQ when administered together with quinidine (largest p value less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2004

Remnant-like lipoproteins, hormone therapy, and angiographic and clinical outcomes: the Women's Angiographic Vitamin & Estrogen Trial.

BACKGROUND: Little is known about the impact of post-menopausal hormone therapy on remnant-like particle (RLP) concentrations and about the relationship between RLP concentration and angiographic progression of coronary artery disease and clinical events in women. METHODS: RLP cholesterol and triglyceride levels were measured at baseline and 3 months after randomization in 397 post-menopausal women enrolled in The Women's Angiographic Vitamin & Estrogen (WAVE) trial. Correlates of baseline RLP levels and changes in levels with post-menopausal hormone therapy were determined with multiple linear regression. Coronary angiography was performed at baseline and after a mean of 2.9 years. Changes in minimal and average luminal diameter were modeled with multivariate linear regression, clinical outcomes (non-fatal myocardial infarction, stroke, or cardiovascular death) with multiple logistic regression. RESULTS: The mean subject age was 65 years, 66% of subjects were white, 18% of subjects smoked, most subjects were overweight or obese, and 35% of subjects had diabetes mellitus. RLP cholesterol (0.277 +/- 0.254 mmol/L) and triglyceride (0.386 +/- 0.552 mmol/L) levels corresponded approximately to the 90th percentile in women in the Framingham study. RLP levels did not change significantly with hormone therapy. RLP levels at baseline, changes in RLP levels, and on treatment RLP levels did not relate to angiographic changes or clinical outcomes (non-fatal myocardial infarction, stroke, or cardiovascular death). CONCLUSIONS: RLP levels were high among post-menopausal women enrolled in the WAVE study, were not affected by hormone therapy, and did not relate to angiographic progression of coronary artery disease or clinical outcomes.

Aged↗

PubMed2002

Higher dietary variety is associated with better nutritional status in frail elderly people.

OBJECTIVE: A narrow range of food choices may lead to dietary inadequacies, a particular concern in elderly people. We hypothesized that consumption of a more diverse diet would predict better nutritional status in frail elderly persons. SUBJECTS: Subjects included 98 frail nursing home residents (36 men, 62 women), mean age 87.1+/-5.5 (72 to 98) years. METHODS: 3-day dietary variety scores ranging from 23 to 48 and fruit and vegetable variety scores ranging from 5 to 20 were calculated from weighed 3-day food records as the number of different food or fruit and vegetable choices consumed. A higher score indicates a more varied diet. Nutritional status was assessed by weight, height, body mass index (BMI), skinfold thickness, circumference measures, calculated mean arm muscle area, total body water, computerized tomography of the thigh, and total body potassium, as well as nutritional analysis, biochemical measures, and subject medical history. STATISTICAL METHODS: Univariate regression analyses were performed to investigate the relationship between clinical and nutrition variables. Multiple linear regressions were used to develop models relating dietary variety scores to possible etiologic factors as well as indicators of nutritional status. Models were controlled for age, BMI, and energy intake when appropriate. RESULTS: Mean dietary variety score was 35.2+/-4.5, and mean fruit and vegetable variety score was 11.3+/-3.0. Higher dietary variety score was associated with higher energy intake (beta = 20.5, P < .001) and both high dietary variety score and fruit and vegetable variety score were positively associated with intake for many nutrients (P < or = .05). High dietary variety score was related to high fruit and vegetable variety score and total intake of fruits and vegetables. In men, higher dietary variety score and fruit and vegetable variety score were associated with higher high-density lipoprotein (beta = 1.02), lower very-low-density lipoprotein (beta = -3.58) and triglycerol (beta = -3.51), and higher blood folate (beta = 4.72) concentrations in women (P < or = .05). In women, high dietary variety score was associated with higher BMI (beta = 0.34, P < .001) and higher total body potassium (beta = 1.30, P = .02); high fruit and vegetable variety score was associated with higher BMI (beta = 0.41), mid-arm circumference (beta = 0.34), and mid-arm muscle area (beta = 2.94) (P < or = .03). Dietary variety score was higher (mean 37.6+/-5.38 vs 34.6+/-4.14) in those who received assistance with feeding (beta = 2 .67, P = .01). History of cancer (beta = -2.04) and gastrointenstinal cancer (beta = -3.54) were associated with low dietary variety score (P < or = .05). CONCLUSIONS: The results of this study suggest that a highly varied diet in elderly nursing home residents is associated with better nutritional status as assessed by nutrient intake, biochemical measures, and body composition measures. Dietary variety score is a straightforward tool for screening and identifying people at nutritional risk, as well as a mechanism for monitoring response to nutritional, medical, and environmental interventions. Preventive measures to improve dietary variety, as measured by the dietary variety score, should be evaluated and introduced before nutrition and health complications arise.

Aged↗

PubMed1991

Prediction of gas chromatographic relative retention times of stimulants and narcotics.

The ADAPT software system was used to create models for the prediction of gas chromatographic relative retention times (RRTs) of stimulants and narcotics that are analyzed in doping control of athletes. The two main methods that were followed for building the models were the quantitative structure-retention relationship (QSRR) and multiple linear regression analysis. The main proposed model for the entire data set had a multiple correlation coefficient R = 0.991 and standard error s = 0.046 or approximately 4.5%. Because of the relatively high standard error of the main model, a second model was built on a subset of compounds with R = 0.982 and s = 0.027 or approximately 2.5%.

Central Nervous System Stimulants↗

PubMed1997

Comparison between estimates of hand volume and hand strengths with sex and age with and without anthropometric data in healthy working people.

Edema and hand strength measurements are useful for the recovery assessment of patients with a hand lesion. This work determined and compared estimates of hand volume, grip strengths (measured with a Jamar and a Collins dynamometer), and pinch strength (with a Jamar pinch gauge) in terms of sex and age with or without anthropometric indices in healthy working people. The sample included 100 subjects from within the staffs of two rehabilitation centres. For both grip strengths, multiple linear regression models including body height, weight, and arm muscle area were very good (multiple correlation coefficient R of about 0.84) and clearly better than those obtained with sex and age only. For pinch strength, the best estimate was obtained with sex and arm muscle area (R of 0.76); for hand volume, the model with sex, body height, and weight provided the best result (R of 0.93). These findings suggested that anthropometric indices easy to measure must be taken into account to estimate hand volume and hand strengths.

Adult↗

PubMed1996

Genetic susceptibility to head and neck squamous cell carcinoma.

BACKGROUND: In addition to influences of exposure to carcinogenic compounds, the development of cancer may depend on an individual intrinsic cancer susceptibility. Biomarkers for cancer susceptibility can be powerful additions to epidemiologic analyses. PURPOSE: This multicenter, case-control analysis combines previously published data and new data to substantiate the value of mutagen sensitivity as a biomarker of susceptibility to head and neck squamous cell carcinoma and, more importantly, to gain insight into the interaction between susceptibility and exposure to carcinogens. METHODS: Mutagen sensitivity (mean number of chromatid breaks per cell of cultured lymphocytes treated with bleomycin in the late S-G2 phase of the cell cycle) was determined in 313 patients with head and neck cancer and in 334 control subjects at two major U.S. medical institutions and one European institution, yielding a unique study population. The ages of the case and control subjects, as well as their history of use of tobacco and alcohol, were also recorded. The relationships between variables were analyzed by use of Student's t tests, Spearman's rank correlations, and multiple linear regression. For estimation of cancer risk, crude odds rations (ORs) were measured and multiple logistic regression was performed. All P values were based on two-sided tests. RESULTS: There were no differences across institutions in the distribution of mutagen sensitivity (Kruskal-Wallis test) for both case subjects and control subjects. Values for case subjects were consistently and significantly (P<.0001) higher than values for control subjects in the overall analyses. Age and tobacco or alcohol use did not influence the outcome in terms of mutagen-sensitivity values for either the case or the control subjects. A mean number of breaks per cell dichotomized at 1.0 was found to be the best predictor of a hypersensitive phenotype. For nonsensitive, heavy smokers, the OR was 11.5 (95% confidence interval [CI] = 5.0-26.6). This risk increased dramatically in mutagen-hypersensitive, heavy smokers to 44.5 (95% CI = 17.4-114.0). Multiple logistic regression analysis confirmed these results, and a significant trend was found (P<.01) for the dose-dependent increase in cancer risk by smoking. The consumption of alcohol potentiated the effects of smoking, resulting in an OR of 57.5 (95% CI = 17.5-188.0) in hypersensitive persons. CONCLUSIONS: Mutagen sensitivity was found to be a biomarker of cancer susceptibility. This study underscores the importance of utilizing both susceptibility markers and the exposure data for the identification of persons at high risk of developing cancer. IMPLICATIONS: More accurate risk estimation can define susceptible subgroups who might be targeted for intensive behavioral interventions, surveillance through screening, and enrollment in chemoprevention programs.

Adult↗

PubMed2005

Nearest-neighbor thermodynamics of deoxyinosine pairs in DNA duplexes.

Nearest-neighbor thermodynamic parameters of the 'universal pairing base' deoxyinosine were determined for the pairs I.C, I.A, I.T, I.G and I.I adjacent to G.C and A.T pairs. Ultraviolet absorbance melting curves were measured and non-linear regression performed on 84 oligonucleotide duplexes with 9 or 12 bp lengths. These data were combined with data for 13 inosine containing duplexes from the literature. Multiple linear regression was used to solve for the 32 nearest-neighbor unknowns. The parameters predict the T(m) for all sequences within 1.2 degrees C on average. The general trend in decreasing stability is I.C > I.A > I.T approximately I. G > I.I. The stability trend for the base pair 5' of the I.X pair is G.C > C.G > A.T > T.A. The stability trend for the base pair 3' of I.X is the same. These trends indicate a complex interplay between H-bonding, nearest-neighbor stacking, and mismatch geometry. A survey of 14 tandem inosine pairs and 8 tandem self-complementary inosine pairs is also provided. These results may be used in the design of degenerate PCR primers and for degenerate microarray probes.

Base Pair Mismatch↗

PubMed1983

Factors contributing to the variability in serum lipid levels and blood pressure in a large kindred.

A 267-member, five-generation Caucasian kindred, that was originally from Evans County, Georgia, and that had a high incidence of cardiovascular disease, was chosen for a study of factors that may make significant contributions to the observed variability in serum lipid levels and blood pressure. A total of 234 of the 240 living members of the family agreed to participate and were examined in the summer of 1978 either at a clinic in Claxton, Georgia, or in their homes. Total serum cholesterol, triglycerides, high density lipoprotein cholesterol, systolic and diastolic blood pressures, height, weight, and two skinfold thicknesses were transformed to natural logarithms, and then adjusted for significant age effects by polynomial regressions on age, separately for each sex. These adjusted variables were then regressed on behavioral traits such as cigarette smoking using a step-wise, multiple linear regression procedure to determine the best fitting linear models. For males, behavioral traits accounted for 41.39% (R2) of the variance in height, 15.01% in weight, 19.51% in subscapular skinfold, 30.28% in triceps skinfold, 10.19% in triglycerides, 8.25% in total cholesterol, 15.81% in high density lipoprotein cholesterol, 21.32% in systolic blood pressure, and 28.23% in diastolic blood pressure. For females, the behavioral traits accounted for 31.40% of the variance in height, 25.99% in weight, 15.80% in subscapular skinfold, 9.84% in triceps skinfold, 7.20% in triglycerides, 21.08% in total cholesterol, 16.69% in high density lipoprotein cholesterol, 9.91% in systolic blood pressure, and 1.55% in diastolic blood pressure.

Age Factors↗

PubMed2002

Tumor necrosis factor receptor levels are associated with carotid atherosclerosis.

BACKGROUND AND PURPOSE: Recent evidence suggests that atherosclerosis is an inflammatory condition. Serum levels of inflammatory markers may serve as measures of the severity of atherosclerosis and risk of stroke. We sought to determine whether tumor necrosis factor-alpha (TNF-alpha) and TNF receptor levels are associated with carotid plaque thickness. METHODS: The Northern Manhattan Stroke Study is a community-based study of stroke risk factors. For this cross-sectional analysis, inflammatory marker levels, including TNF-alpha and TNF receptors 1 and 2, were measured by immunoassay in stroke-free community subjects undergoing carotid duplex Doppler ultrasound. Maximal carotid plaque thickness (MCPT) was measured for each subject. Analyses were stratified by age < 70 and > or =70 years. Simple and multiple linear regression analyses were used to calculate the association between marker levels and MCPT. Multiple logistic regression was used to calculate odds ratios and 95% CIs for the association of inflammatory markers with MCPT > or =1.5 mm (>75th percentile), after adjustment for demographic and potential medical confounding factors. RESULTS: The mean age of the 279 subjects was 67.6+/-8.5 years; 49% were men; 63% were Hispanic, 17% black, and 17% white. Mean values for TNF-alpha and its receptors were as follows: TNF-alpha, 1.88+/-3.97 ng/mL; TNF receptor 1, 2.21+/-0.99 ng/mL; and TNF receptor 2, 4.85+/-2.23 ng/mL. Mean MCPT was elevated in those in the highest quartiles compared with lowest quartiles of TNF receptor 1 and 2 (1.24 versus 0.79 mm and 1.23 versus 0.80 mm, respectively). Among those aged < 70 years, TNF receptor 1 and 2 were associated with an increase in MCPT (mean difference=0.36 mm, P=0.01 for TNF receptor 1 and mean difference=0.10 mm, P=0.04 for TNF receptor 2). After adjustment for sex, race-ethnicity, hypertension, diabetes mellitus, LDL cholesterol, smoking, and body mass index, associations remained (mean difference=0.36 mm, P=0.001 for TNF receptor 1 and mean difference=0.09 mm, P=0.051 for TNF receptor 2). There was no association for TNF receptors in those aged > or = 70 years old and no association for TNF-alpha in either age group. Among those aged < 70 years, each unit increase in TNF receptor level increased the odds of the participant's having MCPT > or =1.5 mm (adjusted odds ratio=4.7; 95% CI, 1.7 to 15.4 for TNF receptor 1; odds ratio=1.9; 95% CI, 1.3 to 2.9 for TNF receptor 2). CONCLUSIONS: Relative elevation in TNF receptor levels, but not TNF-alpha, is associated with carotid atherosclerosis among individuals aged < 70 years in this multiethnic, urban population. Chronic subclinical infection or inflammation may account for this association, and modification of these inflammatory pathways may provide a novel approach to stroke prevention.

Age Factors↗