PubMed Health⌕ Search

Biomedical subjects

R C Ellison

Publications and source records attributed to R C Ellison.

At least 19 recordsLinked to original sources
PubMed2006

Adrenergic receptor polymorphisms associated with resting heart rate: the HyperGEN Study.

The association between polymorphisms in the beta1, beta2 and alpha2B adrenergic receptor (ADR) genes (ADRB1, ADRB2 and ADRA2B) and resting heart rate was examined in white and African-American participants of the HyperGEN Study. All analyses were adjusted for age, sex, body mass index, alcohol use, smoking status and daily exercise within strata of race, hypertension status and beta-blocker use. The Ser49Gly polymorphism of the beta1 ADR was associated with resting heart rate in hypertensive African-Americans and hypertensive whites taking beta-blockers, with carriers of the Gly allele having a higher mean resting heart rate by 2.7 and 4.4 beats per minute (bpm), respectively. The Arg389Gly polymorphism of the beta1 ADR was associated with lower heart rate in the normotensive African-American sample. A beta1 haplotype (Ser49Gly-Arg389Gly) was modestly associated with resting heart rate in the hypertensive African-Americans. The alpha2B C/A polymorphism was associated with heart rate in hypertensive whites, and both whites and African-Americans taking beta-blockers, with carriers of the A allele having a higher mean resting heart rate. In summary, each of the ADR gene polymorphisms was associated with heart rate in at least one stratum studied, but there was no consistent association from which one would infer a large genetic contribution to heart rate.

Adrenergic beta-Antagonists↗
PubMed2005

Sex-specific findings from a genome-wide linkage analysis of human fatness in non-Hispanic whites and African Americans: the HyperGEN study.

OBJECTIVE: To conduct a full genome search for genes potentially influencing two related phenotypes: body mass index (BMI, kg/m2) and percent body fat (PBF) from bioelectric impedance in men and women. DESIGN: A total of 3383 participants, 1348 men and 2035 women; recruitment was initiated with hypertensive sibpairs and expanded to first-degree relatives in a multicenter study of hypertension genetics. MEASUREMENTS: Genotypes for 387 highly polymorphic markers spaced to provide a 10 cM map (CHLC-8) were generated by the NHLBI Mammalian Genotyping Service (Marshfield, WI, USA). Quantitative trait loci for obesity phenotypes, BMI and PBF, were examined with a variance components method using SOLAR, adjusting for hypertensive status, ethnicity, center, age, age2, sex, and age2 x sex. As we detected a significant genotype-by-sex interaction in initial models and because of the importance of sex effects in the expression of these phenotypes, models thereafter were stratified by sex. No genotype-by-ethnicity interactions were found. RESULTS: A QTL influencing PBF in women was detected on chromosome12q (12q24.3-12q24.32, maximum empirical LOD score=3.8); a QTL influencing this phenotype in men was found on chromosome 15q (15q25.3, maximum empirical LOD score=3.0). These QTLs were detected in African-American and white women (12q) and men (15q). QTLs influencing both BMI and PBF were found over a broad region on chromosome 3 in men. QTLs on chromosomes 3 and 12 were found in the combined sample of men and women, but with weaker significance. CONCLUSION: The locations with highest LOD scores have been previously reported for obesity phenotypes, indicating that at least two genomic regions influence obesity-related traits. Furthermore, our results indicate the importance of considering context-dependent effects in the search for obesity QTLs.

Adult↗
PubMed2004

Common variants in the 5' region of the leptin gene are associated with body mass index in men from the National Heart, Lung, and Blood Institute Family Heart Study.

Linkage of body mass index (BMI) to a broad region of chromosome 7q22-35 has been reported in multiple studies. We previously published a multipoint LOD score of 4.9 at D7S1804 for BMI from the National Heart, Lung, and Blood Institute Family Heart Study. Leptin (LEP), the human homolog of the mouse obesity (ob) gene, is positioned near the linkage peak and is the most prominent candidate gene in this region. Interest in LEP as a susceptibility gene for human obesity has led to numerous linkage and association studies, but the results of these studies are still controversial. In the present study, we employed family-based tests of association with both a quantitative measure of BMI adjusted for age and sex and a dichotomously defined obesity trait. We genotyped 29 single-nucleotide polymorphisms (SNPs) spanning 240 kb around the LEP gene in the 82 extended pedigrees with the strongest evidence for linkage. When the programs TRANSMIT and FBAT were used, a number of SNPs showed association in men but not women, for both the quantitative and qualitative trait definitions (P<.05). Five SNPs (H1328084, H1328083, H1328082, H1328081, and H1328080) positioned 2 kb beyond the previously defined promoter region showed strong association in single-marker and multiple-marker haplotype analysis. This five-marker haplotype (frequency 49% in this sample) is overtransmitted to obese offspring (P=.00005). All five of these SNPs are predicted to modify transcription-factor binding sites. This may indicate new functional variants in an extended promoter region of LEP.

Body Mass Index↗
PubMed2004

BMI and waist circumference as predictors of lifetime colon cancer risk in Framingham Study adults.

BACKGROUND: It is unclear whether the increased risk of colon cancer associated with obesity differs for men and women, by distribution of body fat, or by location of the tumor. The primary goal of this study was to address these questions. METHODS: Eligible subjects from the Framingham Study cohort were classified according to body mass index (BMI) and waist size during two age periods: 30-54 y (n=3764) and 55-79 y (n=3802). All eligible men and women were cancer-free at baseline and had complete information on the following potential confounders: age, sex, education, height, activity, smoking, and alcohol. There were 157 incident lifetime cases of colon cancer among those followed beginning at 30-54 y of age and 149 lifetime cases among those whose follow up began at 55-79 y. Subjects were stratified further by gender, activity, and tumor location. The Cox Proportional Hazards Models were used to adjust for possible confounding by the above-described factors. RESULTS: A BMI >/=30 led to a 50% increased risk (95% CI: 0.92-2.5) of colon cancer among middle-aged (30-54 y) and a 2.4-fold increased risk (95% CI: 1.5-3.9) among older (55-79 y) adults. The BMI effect was stronger for men than for women and for cases occurring in the proximal colon. These adverse effects generally diminished when waist was added to the multivariable models. A larger waist size (>/=99.1 cm (39 in) and 101.6 cm (40 in) for women and men, respectively) was associated with a two-fold increased risk of colon cancer; this risk increased linearly with increasing waist size and was evident for both proximal and distal colon cancer. There was no attenuation of these effects when BMI was added to the multivariable models. A larger waist had a particularly adverse effect among sedentary subjects (relative risk (RR)=4.4 for middle-aged adults; RR=3.0 for older adults). CONCLUSION: These findings suggest that waist circumference is a stronger predictor of colon cancer risk than is BMI, and that central obesity is responsible for an increased risk of cancer of both the proximal and distal colon.

Adult↗
PubMed2004

Blood pressure and pulse responses to three stressors: associations with sociodemographic characteristics and cardiovascular risk factors.

Cardiovascular reactivity is hypothesized to increase the risk of hypertension and other CVD-related conditions. However, studies to date are inconclusive. We compared the association of blood pressure and pulse responses to three stressors (postural challenge, handgrip test, mental arithmetic) with sociodemographic characteristics and CVD risk factors. We included 782 participants from the Hypertension Genetic Epidemiology Study. Blood pressure and pulse responses to stressors were defined as the difference between post- and pre-stress measurements. Stepwise regression analyses examined change in SBP and pulse in response to stressors as a function of sociodemographic and CVD risk factors. Age, race, and gender were forced into models and other variables (education, BMI, waist circumference, resting SBP and DBP, cigarette smoking, LDL and HDL cholesterol, glucose, and antihypertensive medications (beta-blockers, calcium channel blockers, diuretics, ace inhibitors)) were retained if P<0.10. Age was a significant predictor of SBP response to all stressors. The SBP response to a change in posture was not related to other variables. The SBP response to mental arithmetic was significantly higher among men, those with larger waists, higher SBP, beta-blocker users, and lower among smokers. SBP response to the handgrip was significantly higher among those with higher SBP and beta-blocker users. Similarly, the association of the pulse response to the risk factors varied considerably across the stressors. Overall, the socio-demographic and CVD risk factors accounted for between 9 and 14% of the variance in the SBP response to the stressors and from between 4 and 12% of the variance in the pulse response to the three stressors. The associations between sociodemographic and CVD risk factors and the SBP and pulse response to stress were modest and inconsistent across stressors. The findings suggest that cardiovascular reactivity is a concept that needs to be defined in reference to specific stressors so that mechanisms leading to responses can be better understood.

Adult↗
PubMed2003

Television viewing and change in body fat from preschool to early adolescence: The Framingham Children's Study.

OBJECTIVE: To prospectively examine the relation between television watching and body fat change in children from preschool to early adolescence. METHODS: In a longitudinal study, 106 children were enrolled during preschool years (mean age 4.0 y) and followed into early adolescence (mean age 11.1 y). Parents completed an annual questionnaire on the child's television and video habits. Body mass index (BMI), triceps skinfolds, and sum of five skinfolds were recorded yearly at annual clinic visits. Longitudinal statistical analyses were carried out using mixed modeling procedures to control for potential confounding by a number of factors. RESULTS: Television watching was an independent predictor of the change in the child's BMI, triceps, and sum of five skinfolds throughout childhood. Its effect was only slightly attenuated by controlling for the baseline body fat, level of physical activity (as measured repeatedly by Caltrac accelerometer), percent of calories from fat, total calorie intake, or the parents' BMI or education. By age 11, children who watched 3.0 h or more of television per day had a mean sum of skinfolds of 106.2 mm, compared with a mean sum of skinfolds of 76.5 mm for those who watched less than 1.75 h per day (P=0.007). Furthermore, the adverse effect of television viewing was worse for those children who were also sedentary or had a higher-fat diet. CONCLUSIONS: Children who watched the most television during childhood had the greatest increase in body fat over time. Healthy lifestyle education designed to prevent obesity and its consequences should target television-watching habits of children.

Adolescent↗
PubMed2001

Bone mineral density and verbal memory impairment: Third National Health and Nutrition Examination Survey.

Previous studies have examined the relation of endogenous estrogen levels or estrogen replacement therapy to the risk of poor cognitive function, but results have been inconclusive. Bone mineral density has been proposed as a marker for cumulative estrogen exposure. The authors studied the relation of bone mineral density to the prevalence of verbal memory impairment among 4,304 elderly subjects in the Third National Health and Nutrition Examination Survey (1988-1994). Bone mineral density was measured in five regions of the proximal femur with dual-energy x-ray absorptiometry. Verbal memory was assessed using delayed recall of a three-item word list and a six-item story. Verbal memory impairment was defined as a combined score of <4. The prevalence of verbal memory impairment for each increasing bone mineral density quintile at the femoral neck was 8.35, 5.74, 5.22, 5.00, and 3.38% in women and 11.54, 7.27, 8.47, 6.29, and 5.89% in men, respectively. With adjustment for age, sex, and other covariates, the prevalence ratios of verbal memory impairment for each increased bone mineral density quintile were 1.00, 0.64, 0.65, 0.55, and 0.44, respectively (p for trend < 0.001). These results suggest that bone mineral density in the elderly is associated with verbal memory impairment. The mechanisms underlying this relation are not understood, but cumulative exposure to estrogen may play a role.

Absorptiometry, Photon↗
PubMed2001

Exploring the relation of alcohol consumption to risk of breast cancer.

There are lingering questions regarding the relation between alcohol consumption and breast cancer risk in women. The authors performed a meta-analysis of epidemiologic studies carried out through 1999 to examine the dose-response relation and to assess whether effect estimates differed according to various study characteristics. Overall, there was a monotonic increase in the relative risk of breast cancer with alcohol consumption, but the magnitude of the effect was small; in comparison with nondrinkers, women averaging 12 g/day of alcohol consumption (approximately one typical drink) had a relative risk of 1.10 (95% confidence interval (CI): 1.06, 1.14). Estimates of relative risk were 7% greater in hospital-based case-control studies than in cohort studies or community-based case-control studies, 3% greater in studies published before 1990 than in studies published later, and 5% greater in studies conducted outside of the United States than in US studies. The findings of five US cohort studies published since 1990 yielded a relative risk of 1.06 (95% CI: 1.00, 1.11) for consumers of 12 g/day, as compared with nondrinkers. Cohort studies with less than 10 years of follow-up gave estimates 11% higher than cohort studies with longer follow-up periods. No meaningful difference was seen by menopausal status or type of beverage consumed.

Alcohol Drinking↗
PubMed2001

Alcohol consumption and hemostatic factors: analysis of the Framingham Offspring cohort.

BACKGROUND: Moderate alcohol consumers have lower rates of cardiovascular disease than abstainers. One proposed mechanism is a beneficial effect on hemostatic parameters, but previous studies have provided conflicting results. METHODS AND RESULTS: We measured levels of fibrinogen, plasma viscosity, von Willebrand factor, factor VII, plasminogen activator inhibitor antigen-1, and tissue plasminogen activator antigen in a cross-sectional analysis of 3223 adults free of cardiovascular disease enrolled in the Framingham Offspring Study. We assessed their alcohol consumption with a standardized questionnaire. Light-to-moderate alcohol consumption was associated with lower levels of fibrinogen, plasma viscosity, von Willebrand factor, and factor VII. This association was most pronounced for consumers of 3 to 7 drinks weekly for viscosity and 7 to 21 drinks weekly for the other hemostatic measures. Alcohol intake of 7 to 21 drinks weekly or more was associated with impaired fibrinolytic potential, reflected by higher levels of plasminogen activator inhibitor antigen-1 and tissue plasminogen activator antigen. Wine drinkers had lower plasminogen activator inhibitor antigen-1 levels than other drinkers, particularly at 3 to 21 drinks weekly, but beverage type did not otherwise consistently affect the results. CONCLUSIONS: Light-to-moderate alcohol consumption is associated with lower levels of coagulatory factors, but higher intake is associated with impaired fibrinolytic potential. These findings are consistent with the hypothesis that a balance between hemostatic and fibrinolytic activity may contribute to the complex relation of alcohol use with coronary heart disease.

Alcohol Drinking↗
PubMed2001

Bone mass and the risk of colon cancer among postmenopausal women: the Framingham study.

Although postmenopausal estrogen use has been associated with a lower risk of colon cancer in women, some studies do not confirm such findings. No known study has examined the effect of cumulative estrogen exposure on colon cancer risk. Bone mass has been proposed as a marker of cumulative exposure to endogenous and exogenous estrogens. By using data on 1,394 Massachusetts women in the Framingham Study who underwent hand radiography in 1967-1970, the authors examined the association between bone mass (from relative areas of the second metacarpal) and colon cancer incidence. Over 27 years of follow-up, 44 incident colon cancer cases occurred. Colon cancer incidence decreased from 2.19 per 1,000 person-years among the women in the lowest age-specific tertile of bone mass to 1.59 and 1.08 among women in the middle and the highest tertiles, respectively. After adjustment for age and other potential confounding factors, the rate ratios of colon cancer were 1.0, 0.7 (95% confidence interval: 0.3, 1.3), and 0.4 (95% confidence interval: 0.2, 0.9) from the lowest to the highest tertile (p for trend = 0.033). No association was found between bone mass and rectal cancer. The findings suggest that women with higher bone mass, perhaps reflecting greater cumulative estrogen exposure, have a decreased risk of colon cancer.

Adult↗
PubMed2001

Relation between dietary linolenic acid and coronary artery disease in the National Heart, Lung, and Blood Institute Family Heart Study.

BACKGROUND: Epidemiologic studies suggest that a higher consumption of eicosapentaenoic acid and docosahexaenoic acid is associated with a reduced risk of cardiovascular disease. Studies in humans and animals also reported an inverse association between alpha-linolenic acid and cardiovascular disease morbidity and mortality. OBJECTIVE: We examined the relation between dietary linolenic acid and prevalent coronary artery disease (CAD). DESIGN: We studied 4584 participants with a mean (+/-SD) age of 52.1 +/- 13.7 y in the National Heart, Lung, and Blood Institute Family Heart Study in a cross-sectional design. Participants' diets were assessed with a semiquantitative food-frequency questionnaire. For each sex, we created age- and energy-adjusted quintiles of linolenic acid, and we used logistic regression to estimate prevalent odds ratios for CAD. RESULTS: From the lowest to the highest quintile of linolenic acid, the prevalence odds ratios of CAD were 1.0, 0.77, 0.61, 0.58, and 0.60 for the men (P for trend = 0.012) and 1.0, 0.57, 0.52, 0.30, and 0.42 for the women (P for trend = 0.014) after adjustment for age, linoleic acid, and anthropometric, lifestyle, and metabolic factors. Linoleic acid was also inversely related to the prevalence odds ratios of CAD in the multivariate model (0.60 and 0.61 in the second and third tertiles, respectively) after adjustment for linolenic acid. The combined effect of linoleic and linolenic acids was stronger than the individual effects of either fatty acid. CONCLUSIONS: A higher intake of either linolenic or linoleic acid was inversely related to the prevalence odds ratio of CAD. The 2 fatty acids had synergistic effects on the prevalence odds ratio of CAD.

Coronary Artery Disease↗
PubMed2001

The feasibility of using rural health workers to determine cause of death in remote regions of Cameroon, West Africa.

The validity of the recent Global Burden of Disease Study (GBDS) was compromised by the lack of adult mortality data in developing countries, particularly in Sub-Saharan Africa. Verbal autopsies, in which health workers (HW), using questionnaires and algorithms, interview surviving family members to determine the cause of death, have proven useful in establishing priorities for the allocation of limited health care resources. Most reports, however, have come from large population centers. The feasibility of using health workers trained in verbal autopsy methodology to operate in remote rural areas of Africa has had limited testing. The records of 40 villagers who died in a Mission Hospital of the Northwest Province of Cameroon were reviewed, and the hospital discharge diagnosis, made by the attending physician, compared with that obtained by HW who administered a verbal autopsy to the family. In 70% of the cases the physician and HW were in exact agreement. Such a method, if confirmed in other studies among rural populations, may be an important approach to determining cause of death in many developing countries.

Cameroon↗
PubMed2000

Alcohol consumption and risk of intermittent claudication in the Framingham Heart Study.

BACKGROUND: Intermittent claudication (IC) is associated with an increased risk of cardiovascular disease morbidity and mortality. The relation of alcohol consumption to the risk of IC remains controversial. The purpose of this study was to assess the relation of alcohol consumption and type of beverage to the development of IC among participants in the Framingham Heart Study. METHODS AND RESULTS: Alcohol consumption was categorized as 0, 1 to 6, 7 to 12, 13 to 24, and >/=25 g/d. During a mean follow-up of 6.8 years, 414 subjects developed IC. From the lowest to the highest category of alcohol intake, the age-standardized incidence rates of IC were 5.3, 4.1, 4.2, 3.2, and 4.6 cases/1000 person-years for men and 3.4, 2.5, 1.5, 1.9, and 2.5, respectively, for women. A multivariate Cox regression model demonstrated an inverse relation, with the lowest IC risk at levels of 13 to 24 g/d for men and 7 to 12 g/d for women compared with nondrinkers; the hazard ratio (95% CI) was 0.67 (0.42 to 0.99) for men and 0.44 (0.23 to 0.80) for women. This protective effect was seen mostly with wine and beer consumption. CONCLUSIONS: Our data are consistent with a protective effect of moderate alcohol consumption on IC risk, with lowest risk observed in men consuming 13 to 24 g/d (1 to 2 drinks/d) and in women consuming 7 to 12 g/d (0.5 to 1 drink/d).

Adult↗
PubMed2000

Hostility, social support, and carotid artery atherosclerosis in the National Heart, Lung, and Blood Institute Family Heart Study.

This cross-sectional study investigates the association of hostility and social support (measured by standardized instruments) to carotid artery atherosclerosis in men and women with a high familial risk for coronary heart disease (CHD) and those with low to medium risk. The hypothesis was that high hostility and low social support would have a stronger association in subjects with a familial predisposition to CHD. There were 535 low- to medium-risk women, 491 low- to medium-risk men, 1,950 high-risk women, and 1,667 high-risk men in the study. The extent of carotid artery atherosclerosis was assessed by B-mode ultrasound imaging. A lesion was defined as an intimal-medial far wall thickness of 1 mm in the common, internal, or carotid bifurcation, or identification of plaque at any site. Odds ratios and their 95% confidence intervals were calculated using generalized estimating equations (GEE) for logistic regression. Family was specified as the clustering variable, and robust SEEs were obtained that account for dependence of the data within families. After controlling for age, education, body mass index, ever having smoked, ever drinking > 5 drinks a day, and metabolic index, hostility was significantly associated with increased odds of carotid lesions in only high-risk women. High-risk women showed a significantly reduced odds of carotid lesions with high social support, but the extent of this protection was reduced when age and education were included in the equation. A combination of high hostility and low social support was associated with higher odds than hostility alone in both high-risk men and women. These results suggest that women with a high familial predisposition for CHD may be more vulnerable to cardiovascular influences from hostility and social support than high-risk men or men and women with low to medium risk.

Adult↗
PubMed2000

Smoking influences the association between apolipoprotein E and lipids: the National Heart, Lung, and Blood Institute Family Heart Study.

Apolipoprotein E allele 4 (apo epsilon4) and smoking each have been associated with an unfavorable lipid profile. We used data collected on 1,472 subjects in the National Heart, Lung, and Blood Institute Family Heart Study to assess whether smoking interacts with apo epsilon4 to influence the levels of plasma lipids. We dichotomized smoking and apo epsilon4 and used analysis of covariance to estimate the means of lipids. Smokers had lower body mass index, were younger, and consumed less fruits and vegetables. Among individuals without apo epsilon4, comparing nonsmokers with smokers, mean low density lipoprotein cholesterol (LDL) was 129.3 and 134.4 mg/dL, respectively, for women and 126.1 and 127.6 mg/dL, respectively, for men. Among subjects with an apo epsilon4 allele, corresponding means were 132.0, and 152.9 mg/dL, respectively, for women and 131.3 and 137.3 mg/dL, respectively, for men (Pfor interaction <0.001 for women and 0.11 for men). A similar interaction was observed for total cholesterol among women (P = 0.02). This study shows a statistically significant effect modification of the relation of apo epsilon4 to LDL and total cholesterol by smoking among women. Smoking may enhance genetic susceptibility to an unfavorable lipid profile among subjects with apo epsilon4.

Adult↗